LA PHYSIQUE AU CANADA
Transcription
LA PHYSIQUE AU CANADA
7 11 VOL. 5 4 , No. 4 I M L ^ J LA PHYSIQUE AU CANADA FEATU Editorial: Communicating Science Opinionr^Anti-Science Attitudes byA Vijh 1998 ( ^ M e d a l l i s t s / Lauréats de l'ACP pour 1998 ND IN THE PHYSICS EDUCATION SECTION Stratospheric Ozone Science and the Internet by A. Fergusson An Instructional Strategy: The Physics of Wave Pools by D. Mathewson " 197 University Prize Exam • 1997 CAP Income Survey / Sondage de l'ACP sur les revenus de 1997 S V > t j f >yR.E.Gree FEATURE ARTICLES Stonehenge I by k. mcnoîii • Archaeological Problems: Scientific Solutions b y D . c . Baird fc, - A History of the Department of Physics and Astronomy at the University of Victoria by G.R. Mason and H.W. Dosso • A Silicon Microtips Field-Emission Display Prototype by C. Py, P. Granl, and M. Gao 1998 Award Winning Lumonics Papers it! SERIE: PK W h e n it c o m e s t o h i g h v o l t a g e p o w e r , o n e c o m p a n y s e t s the the air- i n s u l a t e d h i g h v o l t a g e c o m p o n e n t s are standard. G l a s s m a n . e n c l o s e d . M o d e l s 1 5 0 k V - 5 0 0 k V e m p l o y a n o p e n stack. chassis Because w h e n y o u specify a Glassman product, y o u get more Safety f e a t u r e s i n c l u d e an i n t e l l i g e n t i n t e r l o c k , 'external trip' than a high performance HV D C supply. You invest in world- i n p u t circuit a n d u s e r c o n f i g u r a b l e c u r r e n t r e g u l a t i o n or cur- w i d e r e s o u r c e s o f e x p e r t i s e a n d factory level service. T h e m o s t rent trip m o d e s . c o m p r e h e n s i v e range of c o m p a c t , l i g h t w e i g h t s u p p l i e s i n the i n d u s t r y o f f e r s the p e r f o r m a n c e a n d safety f e a t u r e s y o u n e e d . T h e L T S e r i e s p r o v i d e s 2 0 0 0 W of o u t p u t p o w e r w i t h v o l t a g e r a n g e s f r o m 0 - l k V to an i n c r e d i b l e 0 - 1 5 0 k V , all e n c l o s e d in It a d d s u p to total reliability - in the p r o d u c t , i n d e l i v e r y a n d in support. a 19" r a c k c h a s s i s j u s t 8 . 7 5 " h i g h . T h e u s e r c a n c o n f i g u r e o p e r a t i o n for local or r e m o t e c o n t r o l , a n d l i k e all G l a s s m a n T h e PK S e r i e s h i g h p o w e r h i g h v o l t a g e s u p p l i e s offer a u n i q u e s u p p l i e s is w a r r a n t e d for three years. c o m b i n a t i o n of c o m p a c t c o n s t r u c t i o n a n d r e m o t e c o n t r o l flexibility. Hffjl » " esBcp ] Glassman. From concept to O u t p u t p o w e r is 4 t o 1 5 k W . W i t h c u s t o m e r , the d r i v i n g force in m o d e l s from 0 - 3kV to 0 - 125kV, high voltage power supplies. Series LT Series PK Innovations in high voltage power supply technology. GLASSMAN HIGH VOLTAGE INC. Glassman High Voltage Inc., PO Box 551, Whitehouse Station, NJ 08889, telephone (908) 534-9007, FAX (908) 534-5672. In Canada: (514) 455-7408, FAX (514) 455-7387. Also Glassman Europe, in the UK call (1256) 883007, FAX (1256) 883017 and in Asia, Glassman |apan (044) 877-4546, FAX (044) 877-3395. ft , L™,4» PHYSICS IN CANADA IULY/AUC,UST . 1998 JUILLET/ A O Û T 1 9 9 8 LA PHYSIQUE AU CANADA Index Editorial - C o m m u n i c a t i n g Science, by J.S.C. McKee 1 70 Letters / Lettres In Memoriam: P. Gaunt, O. Hausser, E. Kanasewich Opinion: Anti-Science Attitudes, by A. Vijh 172 183 186 FEATURE ARTICLES / ARTICLES DE FOND 189 S t o n e h e n g e 1, 194 A r c h a e o l o g i c a l P r o b l e m s : S c i e n t i f i c S o l u t i o n s , byD.c. Baird 208 A H i s t o r y o f t h e D e p a r t m e n t o f P h y s i c s a n d A s t r o n o m y at t h e U n i v e r s i t y o f V i c t o r i a , BY K. MCNEILL by G.R. Mason & H . W . D o s s o 217 A S i l i c o n M i c r o t i p s F i e l d - E m i s s i o n D i s p l a y P r o t o t y p e , byc. Py, P. G r a n t , a n d M . Gao LUMONICS BEST STUDENT PAPER COMPETITION WINNERS AT 1998 CAP CONGRESS: 222 226 230 C o h e r e n t G e n e r a t i o n a n d C o n t r o l of Photocurrents in GaAs Using Three C o l o u r Beams b y j . M . Fraser et ai. Coefficient de d i f f u s i o n exact p o u r des systèmes avec des c o n d i t i o n s aux frontières p é r i o d i q u e parj.-F. Mercier A t o m i c O r d e r i n g a n d Surface Instabilities in T h i n Films b y F . Léonard et al. PHYSICS A N D EDUCATION / LA PHYSIQUE ET L'ÉDUCATION 249 Stratospheric O z o n e Science a n d the Internet, 253 A n I n s t r u c t i o n a l Strategy: T h e Physics of W a v e Pools, 254 1997 CAP Undergraduate Prize Examination / Concours du prix universitaire de l'ACP 1997 258 1997 CAP Income Survey / Sondage de l'ACP sur les revenus de 1997, by R.E. Green b y A. Fergusson by D. Mathewson DEPARTMENTS / RUBRIQUES CAP Office / Bureau de l'ACP Calendar / Calendrier Science Policy / La politique scientifique . . . Sustaining Members / Membres de soutien . 1998 CAP Awards News / Nouvelles Corporate Profiles 174 180 181 185 233 242 243 Single Issue Jan., Mar.. July., Sept., Nov. Congress Issue (May) One-Year Contract (6 issues) Full Page $560.00 $610.00 $460.00 Half Page $420.00 $460.00 $360.00 Quarter Page $245.00 $270.00 $210.00 $35.00 $40.00 $30.00 Fourth Cover $705.00 $775.00 $600.00 Second & Third Cover $610.00 $705.00 $510.00 Lines (each 1/2 inch) Colour. $225.00 each additional colour; Bleed $140.00 Typesetting and art time extra Deadline for Booking Space - 2 months prior to issue date Deadline for Co(w - 15th of month prior to issue date Published - Jan/Feb., March/Apr., May/June. July/Aug., Sept/Oct.. Nov/Dec. 246 248 248 261 262 F R O N T C O V E R / PAGE COUVERTURE: "Busy Spiders on a MistyMorning" by/par R.L.Brooks, Univ. of/de Guelph. Printed by M.O.M. Printing Advertising Rates Effective January 1998 News from Corporate Members Corporate Members / Membres corporatifs Institutional Members / Membres institutionels Books Received / Livres reçus Book Reviews / Critiques des livres This 1996 Art of Physics competition entry, which received an honourable mention, is now part of the CAP'S Art of Physics exhibition that is available to any group interested in hosting the display. Visit the CAP's website (http://www.cap.ca/events) for booking information. The full caption for this photograph can be found on page 232. Cette photo a été inscrite au Concours l'Art de la Physique en 1996 et a reçu une mention honorable. Elle fait maintenant partie de l'exposition l'Art de la Physique qui est disponible aux groupes intéressés à la présenter. Visitez le site Web de l'ACP (http://www.cap.ca/events) pour en savoir plus long sur la manière de réserver l'exposition. La description complète de cette photo se trouve à la page 232. EDITORIAL The Journal of the Canadian Association of Physicists La revue de l'Association canadienne des physiciens et physiciennes EDITORIAL BOARD / COMITÉ DE RÉDACTION Editor / Rédacteur en chef Jasper S. McKee Accelerator Centre. Physics Department University of Manitoba Winnipeg, Manitoba R3T 2N2 (204) 474-9874; Fax: (204) 474-7622 e-mail: [email protected] Associate Editor / Rédactrice associée Managing / Administration Francine M. Ford c/o CAP/ACP Honorary Associate Editor / Rédacteur associé honoraire Béla Joôs Physics Department, University of Ottawa 150 Louis Pasteur Avenue Ottawa, Ontario K1N 6N5 (613) 562-5800x6755; Fax:(613) 562-5190 e-mail: [email protected] Book Review Editor / Rédacteur à la critique des livres André Roberge Department of Physics and Astronomy Laurentian University Sudbury, Ontario P3E 2C1 (705) 675-1151x2234; Fax: (705) 675-4868 e-mail: [email protected] Advertising Manager / Directeur de la publicité Michael Steinitz Department of Physics st. Francis Xavier University. P.O. Box 5000 Antigonish, Nova Scotia B2G 2W5 (902) 867-3909; Fax: (902) 867-2414 e-mail: [email protected] Recording Secretary / Secrétaire d'assemblée Rod H. Packwood Metals Technology Laboratories E-M-R. 568 Booth Street Ottawa. Ontano K1A 0G1 (613) 992-2288; Fax: (613) 992-8735 e-mail: [email protected] John G. Cook Institute for Microstructural Sciences National Research Council (M-50) Montreal Rd„ Ottawa. Ontano K1A 0R6 (613) 993-9407; Fax; (613) 990-0202 e-mail: [email protected] Caria C. Miner Sen Manager. Advanced Materials & Processes Bell Northern Research Ottawa. Ontano K1Y4H7 (613) 763-3548; Fax: (613) 763-2404 e-mail: [email protected] René Roy Département de physique. Université Laval Cité Universitaire. Québec G1K 7P4 (418) 656-2655; Fax: (418) 656-2040 e-mail: [email protected] David J. Lockwood Institute for Microstructural Sciences National Research Council (M-36) Montreal Rd.. Ottawa. Ontario K1A 0R6 (613) 993-9614; Fax: (613) 993-6486 e-mail: [email protected] ANNUAL SUBSCRIPTION RATE / ABONNEMENT ANNUEL: $40 00 Cdn + GST or HST (Cdn addresses). $40.00 US (US addresses) $45.00 US (other/foreign addresses) Advertising, Subscriptions, Change of Address/ Publicité, abonnement, changement d'adresse: Canadian Association of Physicists / Association canadienne des physiciens et physiciennes, Suite 112, McDonald Bldg.. 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 Phone: (613) 562-5614; Fax: (613) 562-5615 e-mail: [email protected] Website: http://www.cap.ca Canadian Publication Product Sales Agreement No. 0484202/Envois de publications canadiennes numéro de convention 0484202 ©1998 CAP/ACP All rights reserved. 170 ISSN 0031-9147 PHYSICS IN CANADA EDITORIAL - Communicating Science Looking back in history, it is not long since the presentation of scientific facts and figures to the public was often regarded as an activity neither advisable nor appropriate When I was a young tenured lecturer at Birmingham University in England, it was considered highly inappropriate to attempt to inform the public of recent advances in scientific discovery. The reasons for this were twofold. Firstly, the detailed understanding of new phenomena was the forté of a few people in a given field, and to try and communicate at a low intellectual level the significance of new work was not only to undervalue the effort that many scientists had invested over a long period of time but to trivialize the essential complexity of what had been accomplished. It was also regarded as totally unreasonable to expect a listener or member of the public having neither an undergraduate science degree or even a high school diploma behind them, to appreciate, at any level, the import or significance of a new discovery. Things are different now, but the transition to wholehearted communication of science to the public has been a difficult one and is an activity in which too few of us participate with any enthusiasm. While reflecting on this problem recently, I recalled to mind an interesting column in the San Francisco Examiner of 1967, in which an apocryphal tale of two assistant professors seeking tenure at the University of California at Berkeley was presented. The article announced that a tenured position at the University had become open for competition and that the short list for the appointment comprised two scholars with widely different backgrounds. The first, an expert in Sanskrit, had been employed on a continuing appointment for several years. His work was highly esoteric and when he gave an annual public lecture, as he was obliged to do by the by-laws of the university, it was given in his own rooms and attended by an audience of one, namely his graduate student w h o had worked with him for several years. The second candidate, on the other hand, gave a first year lecture course in Comparative Religions which was among the most popular in the whole university. His enrolment of 2,000 students was limited only by the capacity of the auditorium in which he presented his material. This class was enthusiastic both about his presentation and his content and eager students were known to form a line two hours in advance of each presentation. When the Board of Regents finally came u p with its decision, it was that the professor of Sanskrit be confirmed in a tenured appointment. On being questioned by the press and public as to the nature of this bizarre decision, the Chair of the Board of Regents commented, in relation to the qualifications of the loser, that 'the University of California at Berkeley is one of the great storehouses of knowledge in the western world and this young whipper-snapper is continually giving the stuff away'. July/August 1998 EDITORIAL As w e approach the end of the 20th century, one fact of life that has become crystal clear is that all able and practising scientists are in the business of "giving the stuff away". The "stuff" being scientific knowledge and the ability to apply it to a myriad of both academic and technical situations. The research scientist is now only too well aware of his or her need to inform and woo the taxpaying public, if f u n d i n g for fundamental and applied research is to be forthcoming. In fact, if the scientist is unable to persuade others of the value of the work proposed, then chances of gaining the opportunity to proceed with it will be minuscule at best. It is not only enlightened self-interest, however, that necessitates the communication between the scientist and non-scientist. There exists in the community at large a hunger for increased scientific knowledge and the ability to function in an increasingly technological environment. Some 12 years ago, a study carried out in Europe by OECD indicated that over 60% of the community would welcome or needed further scientific education than they h a d acquired and more scientific information than was readily available to them. In Canada, w e find a burgeoning of scientific journals aimed at the non-scientist or layperson, which partly meet the need for scientific information and illustrate effectively the significance of new discoveries as they come along. The fact that such journals sell with alacrity on most newsstands indicates that the need is there. The continuing popularity of television programs such as The Nature of Things in Canada and Nova in the United States, plus the initial acceptance of the new Discovery Channel, also serve to indicate that there is a healthy hunger in Canadian society for n e w knowledge and new skills. The advent of new-style museums, where interactive exhibits dominate the scene, n o w enables people w h o are otherwise uncomfortable in a scientific or technological environment to educate themselves through button-pressing response mechanisms that enable them to perform more effectively at their workplace or in the home. The reasons as to why a need for science in society has suddenly arisen are many and varied. Clearly, the thirst for scientific knowledge was not confined to the ancient Greeks and there are many today who find areas of scientific endeavour, such as space research, of continuing fascination. There are also people with a modest background in scientific knowledge who continually educate themselves through literature of varying degrees of factual correctness and difficulty. There are housepersons w h o find the home environment a more challenging place than it has ever been in the past. The advent of the home computer, the microwave oven, the garburetor, the television set with its VCR attachment, the electronic dust precipitator, and the year-round air conditioning system all require new, if modest, technical skills on behalf of the user if they are to be operated effectively. In addition, there are always a number of people in the community w h o do not trust scientists further than they could throw them, and eagerly acquire such scientific information as is available in order to keep, as it were, a check on the scientists and what they are doing. The evolution of a scientific culture in Canada is becoming essential to the generation of a highly skilled work force and a vibrant economy. The traditional idea that there exist two separate cultures within society - a scientific culture and a humanistic culture - is becoming passé. If a culture is indeed the sum total of the beliefs and experiences of a society, then the interaction between science and the society it serves has to be ongoing and develop to the benefit of all. The ubiquitous nature of science requires that scientific knowledge and training be made available to any and all that wish it. Public awareness is but one side of the coin. Science education and technical training is the other. Effective communication is essential to both. J.S.C. McKee E d i t o r , Physics in Canada LA PHYSIQUE AU CANADA juillet à août, 1998 171 LETTERS LETTERS / LETTRES MINIMUM AND MAXIMUM GRANTS Reading the Review of Canadian Academic Physics (published by CAP, April 1998), I found Recommendations 7 and 8 (page 12) particularly odd. The first one tells us that there is a "minimum useful grant" and even puts its value around $20,000 for experimentalists and $10,000 for theorists. The second recommendation rejects the idea there should be an upper limit (cap) on the grant. As a theorist, let me start with the alleged "minimum useful theoretical grant". There are many research-active professors in theoretical (and computational) research at Canadian universities who are systematically denied ANY operating grants ("NIL awards"). For many of them the only source of research funding is their annual faculty allowance, which is normally about $1,000 to $1,200 per year. Not much, but $3 per day is better than nothing. Many manage to get a reasonably good mileage from it. This is evident from sustained output of peer reviewed papers (and if peer review is worthy its name, this means their work is recognized as meritorious by a professional community). For such academics, an NSERC grant of just $1,000 per year almost doubles the amount of their research budget. It, for example, can be used to offset costs of computer updates, conference attendance, etc. A grant of $3,000 to $5,000 per year allows the offsetting of some other research expenses, e.g. accommodation of short term visitors to enhance possibilities of research cooperation, etc. This is not to suggest, that all theoretical grants should be at $1,000 to $3,000 level, but to call $10,000 a "minimal useful grant" is a sheer nonsense. No amount of research cash is useless. Hence the NSERC component for such research should be reduced (not increased), perhaps even below the average grant level for a given research area. For all practical purposes, cap for a maximum grant in a given area should likely be about 2 to 3 times the size of the average grant for this (sub)discipline. The Review essentially ignores numerous studies showing that draconian "competition" and "selectivity1 leads to proliferation of conformism and mediocrity and suppresses (rather than encourages) true originality (see, e.g., R. Gordon, "Accountability in Research", Vol. 2,1993, p. 297). Contrary to Review's endorsements of continuation of "selectivity" policy, we need a much more uniform funding system, such that only clearly incompetent work is denied any funding. Such a system should be based on a continuous ranking of grant amounts rather than on sharp cut-offs. A system of "Stars and Celebrities" in science has never worked and never will. Its promotion is wrong socially and wasteful economically, no matter how appealing such a system looks for presently dominant corporate ideology. We do not need casts of rich and destitute professors at our universities. We need all of them having at least base means to contribute to creative teaching and research. And if NSERC is unable (or unwilling) to offer a less stressful research environment, it is time to abolish it and replace it with less complicated funding system which will assure some funding for all productive academic researchers. Alexander A. Berezin Department of Engineering Physics McMaster University Hamilton, Ontario L8S 4L7 The recommendation that there should be no upper limit is even more bizarre. Even in a hypothetical limit that all NSERC budget is used to fund a sole ("greatest") Canadian scientist, it still will be capped by the total NSERC budget. But even such an extreme aside, the assumption that "top quality grantees should get top grants" simply does not hold water. By definition, the work which claims to be of top quality (and hence exceptionally "important") should have no difficulty in attracting funding from other sources. 172 PHYSICS IN CANADA J u l y / A u g u s t 1998 A LOOK TOWARDS THE THIRD MILLENIUM: MEDICAL PHYSICS Physicists can look back over their outstanding achievements in the 20th century with a sense of pride. The first half of this century has seen the development of LETTRES relativity theory, quantum mechanics and the theory of atomic structure. The second half of this century has seen outstanding achievements in nuclear physics and in quantum electronics (lasers and masers), solid state physics has led to important applications of transistors and integrated circuits in the computer industry, fiber optics has introduced new developments in the communication industry. The conquest of space is without doubt a fascinating application of the laws of gravitation. It has been said that the challenge of the 21th century will be the application of science to medicine and to environmental problems. As a theoretical physicist who has worked for 6 years in hospitals and who has done extensive work in the modeling of the mechanics of cardiac contraction [1,2], it is my opinion that theoretical physics will have the same impact on the advancement of medicine that it had on the advancement of physics. It is unfortunate that not many physicists seem to realize this evolution that is taking place and will have a far reaching impact on our knowledge in biology and in physiology. An increasing number of areas in medicine are using instrumentation that relies heavily on our knowledge in physics like X-rays, magnetic resonance imaging (MRI), positron emission tomography (PET), computerized axial tomography (CAT), ultrasound imaging and doppler ultrasound. These techniques are used to detect tumors and other abnormalties in brain, lungs, kidneys, heart and other parts of the body. The Nobel committee recognized this important contribution of physics to medicine by awarding the 1979 prize for medicine to U.S. physicist Allan Cormack and British researcher Godfrey Hounsfield, who worked out independently the mathematics of what we call now CAT scanning. The application of electromagnetism to medicine has allowed the development of electrocardiograms (ECG) and made possible the easy detection of cardiac abnormalities. The same thing can be said about electroencephalograms (EEG) and electromyograms (EMG). Neurophysiology and the propagation of nerve impulses as well as the study of the bioelectricity of cells are more examples of the application of electromagnetic theory to medicine. Fluid dynamics plays a fundamental role in modeling blood flow in arteries and in the study of the pump function of the heart. Transport phenomena are extremely important in the study of the way the blood carries oxygen and other nutrients to tissues, as well as in the study of the effect of drugs on the body. Diffusion processes are important in the study of the exchange of gases in the lungs as well as the diffusion of nutrients through membranes and to the foetus in the womb of the mother. Studies of DNA molecules rely heavily on forces between atoms and molecules that are studied essentially by means of quantum mechanics. The physical concepts behind the way a person thinks, sees, hears, speaks, tastes, feels, walks, the birth of a baby (the greatest miracle of nature !!), are all marvellous and fascinating. They reflect the most ingenious physical design that has ever been created in our world and probably in the universe. It is my opinion that there is a need to reorient the teaching of physics in our universities in a way to add to the traditional study of inert matter the study of the physics of living matter. I suggest that courses in mathematical physiology and/or theoretical biology (like mathematical physics) can be introduced at the undergraduate level in physics departments in such a way as to draw the curiosity of young physicists and to awake their interest in medical physics. The traditional teaching of physics seems to have succeeded in forming graduates who have excelled in research and in laboratory work. There is a need nowadays to put more emphasis on the education of our young physicists so that they can meet the growing challenges of industry and of hospital work. All these ideas were in my head when I wrote a letter to Dr. Bev Robertson in 1997 to suggest the reactivation of the Division of Medical and Biological Physics (DMBP) which existed only on paper, idle for over 10 years. The letter found its way to the hands of his successor as President of the CAP, Dr Eric Svensson. He took, together with the executive of the CAP, the far-sighted decision to encourage this initiative. This explains the announcement concerning the reactivation of the DMBP that appeared in Physics in Canada [3]. The author would like to express his gratitude to all those who encouraged this initiative, and in particular Dr. Eric Svensson. It is my hope that the new president of the CAP, Dr. Michael Steinitz, will continue efforts to make the reactivation of the DMBP a permanent reality in the activities of our association. References: [1] R. M. Shoucri, Am. ]. Physiol. 260, H282-H291 (1991) [2] R. M. Shoucri, IEEE Eng. Med. Biol. 17, 95-104 (1998) [3] Physics in Canada ( M a y / J u n e 1998) LA PHYSIQUE AU CANADA Rachad M. Shoucri Royal Military College of Canada Kingston, Ontario, e-mail: [email protected] juillet à août, 1998 173 C A P OFFICE C A P O F F I C E / BUREAU DE L'ACP CAP OFFICE STAFF PERSONNEL D U BUREAU DE L'ACP During the past year, the CAP Office has undergone a number of staffing changes. We took this opportunity to restructure the office in an effort to better meet the needs of the membership. To this end, we are pleased to report that the current complement of staff include: Au cours de la dernière année, le bureau de l'ACP a subi de nombreux changements de personnel. Nous en avons profité pour restructurer le bureau afin de mieux répondre aux besoins de nos membres. À cette fin, nous sommes heureux de vous annoncer les noms du personnel actuel qui comprend : Francine Ford, CAP Executive Director. Francine has been with the Association since September of 1991. In addition to being responsible for the overall management of the CAP Office, Francine also holds the positions of Managing Editor of Physics in Canada and Science Policy Officer for the CAP. Francine Ford, Directrice exécutive de l'ACP. Francine travaille à l'Association depuis le mois de septembre 1991. En plus d'être responsable de l'ensemble de la gestion du bureau de l'ACP, Francine occupe les postes de rédactrice associée de La Physique au Canada et d'agent de politique scientifique de l'ACP. Carmen Harvey, w h o has been with the Association since November 1995, is n o w the CAP's Receptionist/ Administrative Assistant, working five days per week. In addition to being the first voice you normally hear w h e n you call the CAP Office, Carmen is the staff member responsible for membership matters and Physics in Canada subscriptions. Carmen Harvey travaille à l'Association depuis le mois de novembre 1995. Elle occupe maintenant le poste de réceptionniste/ assistante administrative de l'ACP à temps plein. Carmen est normalement la première personne à qui vous parlez lorsque vous appelez le bureau de l'ACP et elle est responsable des questions relatives aux membres et des abonnements à La Physique au Canada. The newest member of the office staff is Tony Bove w h o was hired on contract starting April 6 th of this year. Tony currently works four days per week (Monday to Thursday) as the C A P s Special Projects Officer. His primary responsibilities include the typesetting of Physics in Canada and the upgrading and maintenance of the C A P s website. Le tout nouveau membre du personnel est Tony Bove qui a été engagé à contrat le 6 avril 1998. Tony tra vaille en ce moment quatre jours par semaine (du lundi au jeudi) en tant qu'agent des projets spéciaux de l'ACP. Son travail consiste principalement à faire la composition de La Physique au Canada et à améliorer et maintenir à jour le site Web de l'ACP. Contact information: Suite 112, McDonald Building Ottawa, Ontario K I N 6N5 Tel: (613) 562-5614; Fax: (613) 562-5615 E-mail: [email protected] (general) [email protected] (Francine Ford) [email protected] (Carmen Harvey) [email protected] (Tony Bove) Renseignements : Bur. 112, Imm. McDonald Ottawa (Ontario) KIN 6N5 Tél: (613) 562-5614; Fax: (613) 562-5615 Couriel: [email protected] (général) [email protected] (Francine Ford) [email protected] (Carmen Harvey) [email protected] (Tony Bove) Please feel free to contact our office with any comments or suggestions on h o w the services to members can be improved. Notre bureau sera heureux d'accepter tout commentaire ou suggestion sur la façon d'améliorer le service aux membres. 174 PHYSICS IN CANADA July/August 1998 BUREAU DE L ' A C P L'EXECUTIVE DE L'ACP POUR 1998-99 MEET YOUR 1998-99 EXECUTIVE Dr. Michael Steinitz - CAP President Dr. Marie D'lorio - CAP Vice-President Dr. Gordon W.F. Drake-CAP Vice-President Elect Marie D'lorio est un agent de recherche sénior au Conseil national de recherches du Canada. Originaire de Montréal, elle a été éduquée à O t t a w a où l'apprentissage de l'anglais f u t assez ardu. Elle a reçu son B.Sc. spécialisation physique à l'université d ' O t t a w a . Elle a entrepris des études supérieures en physique de la matière condensée sous la direction de Robin A r m s t r o n g à l'université de Toronto pour obtenir une Maîtrise et un Doctorat ( 1 9 8 2 ) . Après un stage post-doctoral d ' u n an avec Alex Muller à IBM Zurich, elle est revenue à O t t a w a pour mettre sur pied au CNRC un programme de recherche sur les propriétés de transport électronique dans les structures quantiques semiconductrices à très basse température. Elle s'intéresse maintenant aux couches minces moléculaires et polymériques pour les applications photoniques et électroniques. Elle est également professeur auxiliaire à l'université d ' O t t a w a , membre du comité du sélection pour le programme chercheur-boursier industriel du CFISNG et membre du Comité consultatif de la Revue canadienne de physique. Elle s'intéresse aussi à son mari (physicien, bien sûr), ses deux enfants, sa jumelle identique (non-physicienne) et beaucoup de parenté. Gordon Drake is currently Professor and Chair of the Department of Physics at the University of Windsor. He received his B.Sc. degree from McGill University in 1 9 6 5 , M.Sc degree f r o m the University of Western Ontario in 1966, and Ph.D degree f r o m York University in 1967. Prestigious awards include the CAP Herzberg Medal, 1 9 7 9 ; Steacie Prize, 1 9 8 1 ; Killam Fellowship, 1 9 9 0 - 9 2 , and the CAP Medal for Achievement in Physics, 1995. He became a Fellow of the Royal Society of Canada in 1986, and is currently serving as Director of the Mathematical and Physical Sciences Division of the RSC. V Michael Steinitz w a s born in N e w Y o r k City in 1 9 4 4 to refugee parents. He received his Bachelor of Engineering Physics in a co-op program f r o m Cornell University in 1 9 6 5 , having attended Columbia University, t h e University of Pennsylvania (for studies in history, philosophy and international relations) and the University of Goettingen, Germany (on a Cornell scholarship) along the w a y . He received his Ph.D. in Materials Science f r o m N o r t h w e s t e r n University in 1970. A f t e r t w o years as a post-doc in the physics department and a year as a research associate in the metallurgy department at t h e University of Toronto, he accepted a position as assistant professor at St. Francis Xavier University, where he became full professor in 1 9 8 3 . Since 1 9 7 4 he has been adjunct professor at the Technical University of Nova Scotia and since 1 9 9 3 he has been adjunct professor in the school of graduate studies of Dalhousie University. He has t w i c e been Lady Davis visiting professor for a year at the Technion in Haifa, Israel. Contact information: Prof. M.O. Steinitz Department of Physics St. Francis Xavier University P.O. Box 5 0 0 0 ANTIGONISH NS B2G 2 W 5 Tel: (902) 8 6 7 - 3 9 0 9 Fax: (902) 8 6 7 - 2 4 1 4 E-mail: m s t e i n i t @ j u l i e t . s t f x . c a Contact information: Dr. M. D'lorio Institut des sciences des microstructures Conseil national de recherches du Canada 1 5 0 0 Montreal Rd., M - 5 0 , Rm. 178 O t t a w a , ON K1A 0R6 Tel: (613) 9 9 3 - 4 5 9 7 Fax: (613) 9 9 0 - 0 2 0 2 E-mail: marie.d'[email protected] Recent services to the academic community include Chair of the A t o m i c , Molecular and Optical Physics Division of the American Physical Society, 1 9 9 6 - 9 7 , Chair of the CAP/ NSERC Committee to review General/Space Physics in Canada, 1 9 9 6 - 9 7 ; Chair of the Task Force to review Physical Review A, 1 9 9 6 - 9 7 ; Chair of the General Physics Steering Committee for NSERC Reallocations, 1 9 9 7 ; Chair of the Local Organizing Committee for the XVI International Conference on A t o m i c Physics, 1 9 9 8 ; Chair of IUPAP Commission C 1 5 , 1 9 9 3 - 9 6 , 1 9 9 6 - 9 9 ; Divisional Associate Editor, Physical Review Letters, 1 9 8 5 - 9 4 ; and Co-Editor, Canadian Journal of Physics, 1 9 9 7 - 2 0 0 2 . He has also served on the NSERC Grant Selection C o m m i t t e e for Physics, 1 9 8 1 - 8 4 ; Killam Fellowship Selection Committee, 1 9 9 2 - 9 5 ; APS Davisson-Germer Prize Committee, 1 9 9 1 - 9 3 ; Polanyi Prize Committee 1 9 9 3 - 9 6 ; and Chair of the CAP/CRM Prize Committee, 1998. His main area of research involves high precision calculations for the energies, relativistic and q u a n t u m electrodynamic effects in f e w - b o d y atomic systems such as helium and lithium, and the interpretation of high precision measurements o f transition frequencies and other atomic properties. A recent major publication is the A t o m i c , Molecular and Optical Physics Handbook (AIP Press, New York, 1996). THE OTHER MEMBERS of the 1998-99 CAP Executive include: Past President Dr. Eric Svensson National Research Council of Canada Steacie Institute, Neutron Program Chalk River Laboratories, Stn 18 Chalk River, ON KOJ 1J0 Secretary-Treasurer Dr. Gary Enright Steacie Institute National Research Council 100 Sussex Drive, Rm 126 O T T A W A ON K 1 A 0 R 6 Tel: (613) 5 8 4 - 3 3 1 1 x 3 9 9 2 Fax: (613) 5 8 4 - 4 0 4 0 Tel: (613) 9 9 3 - 7 3 9 3 Tel: (613) 9 5 4 - 5 2 4 2 E-mail: [email protected] E-mail: [email protected] LA PHYSIQUE AU CANADA Contact information: Dr. G.W.F. Drake Department of Physics University of Windsor Windsor, Ontario N9B 3P4 Tel: (519) 2 5 3 - 4 2 3 2 Ext. 5 0 4 1 Fax: (519) 9 7 3 - 7 0 7 5 e-mail: A 3 6 @ s e r v e r . u w i n d s o r . c a juillet à août, 1998 175 C A P OFFICE 1998/99 CAP COUNCIL MEMBERS SELECTED At the 1998 June 16 Annual General Meeting, the slate of nominations for the 1998/99 CAP Council was confirmed. The following is the list of your executive and Council members, with contact information. Please feel free to send any suggestions or comments regarding the operations of the CAP to any of these listed representatives. SÉLECTION DES MEMBRES DU CONSEIL DE L ACP 1998-1999 Lors de l'Assemblée générale annuelle le 16 juin 1998, les membres ont approuvé la liste des candidats au Conseil de l'ACP pour l'année 1998-1999. Vous trouverez ci-dessous la liste de vos membres siégeant à l'Exécutif et au Conseil ainsi que l'information pour les contacter. Vous pouvez contacter les représentants sur cette liste concernant tout commentaire ou suggestion sur le fonctionnement de l'ACP. Executive Members / Membres de l'éxecutive: Presiden t/Présiden t: Dr. Michael Steinitz, St. Francis Xavier Univ. Tel: (902) 867-3909; Fax: (902) 867-2414 E-mail: [email protected]. ca Atomic & Molecular/Atomique et moléculaire: Dr. S. David Rosner, Univ. of Western Ontario Tel: (519) 661-3324 ; Fax: (519) 661-2033 E-mail: rosner@julian. uwo. ca Vice-President/Vice-présidente: Dr. Marie D'lorio, National Research Council Tel: (613) 993-4597; Fax: (613) 952-8701 E-mail: [email protected]. nrc. ca Canadian Geophysical Union/Union géophysique canadienne: Dr. Roy Hyndman, Geological Survey of Can. Tel: (604) 363-6428 ; Fax: (604) 363-6565 E-mail: [email protected] Vice-President Elect/Vice-président élu: Dr. Gordon W.F. Drake, University of Windsor Tel: (519) 253-4232x2656; Fax: (519) 973-7075 E-mail: A36@server. uWindsor.ca Condensed Matter & Materials/Matière condensée et matériaux: Dr. John H. Page, University of Manitoba Tel: (204) 474-9852 ; Fax: (204) 269-8489 E-mail: jhpage@physics. umanitoba. ca Past President/Ancien président: Dr. Eric Svensson, National Research Council Tel: (613) 584-3311x3992; Fax: (613) 584-4040 E-mail: [email protected] Industrial & Applied/Industrielle et appliquée: Prof. Xiaoyi Bao, Univ. of New Brunswick Tel: (506)458-7297; Fax: (506)453-4581 E-mail: xb@unb. ca Sec re tary- Treasurer/Sécre taire/trésorier: Dr. Gary Enright, National Research Council Tel: (613) 993-7393 ; Fax: (613) 954-5242 E-mail: enrig h t@ned1. sims. nrc. ca Medical and Biological/médicale et biologique: Dr. David Chettle, McMaster University Tel: (905) 525-9140 x27340; Fax: (905) E-mail: chettle@mcmail. cis. mcmaster. ca Directors/Directeurs: Nuclear/Nucléaire: Dr. W. T. H. van Oers, University of Manitoba Tel: (604) 222-1047; Fax: (604) 222-1074 E-mail: vanoers@reg. triumf. ca Full Members/Membres titulaires: Dr. Robert C. Barber, Univ. of Manitoba Tel: (204) 474-9817 ; Fax: (204) 269-8489 E-mail: barber@physics. umanitoba. ca Optics & Photonics/Optique et photonique: Dr. Michel Tetu, Laval University Tel: (418) 656-2146 ; Fax: (418) E-mail: michel. tetu@gel. ulaval. ca Affiliate Members/Membres affiliés: Mr. Donald Mathewson, Vancouver,B.C. Tel: (604) 221-4320 Physics Education/Enseignement de la physique: Dr. Derek Lawther, University of P.E.I. Tel: (902) 566-0338; Fax: (902) 566-0420 E-mail: [email protected] Student Members/Membres étudiant(e)s: Mr. Michael Levi, Queen's University Tel: (613) 531-4071 E-mail: 4mal2@qlink. queensu. ca Plasma/Plasmas: Dr. Robin Marjoribanks, University of Toronto Tel: (416) 978-6769; Fax: (416) 971-2068 E-mail: marjoribanks @ph ysics. u toron to. ca Professional Affairs/Affaires professionelle: Dr. Don McDiarmid, National Research Council Tel: (613) 990-0713 ; Fax: (613) 952-6605 E-mail: [email protected] Academic Affairs/Affaires academique: Dr. Catherin Kallin, McMaster University Tel: (905) 525-9140 x23176 ; Fax: (905) E-mail: [email protected] 521-2773 des divisions: Atmospheric & Space/Atmosphérique et l'espace: Dr. D.J. Knudsen, University of Calgary Tel: (403) 220-8651; Fax: (403) 282-5016 E-mail: [email protected]. ca 176 PHYSICS IN CANADA 656-3159 Particle/Particules: Dr. J. Michael Roney, University of Victoria Tel: (250) 721-7746; Fax: (250) 721-7752 E-mail: [email protected] Corporate Members/Membres corporatifs: Mr. Sean Duffin, Varian Canada Tel: (905) 819-8181 ; Fax: (905) 819-8348 E-mail: sean. duffin @sco. varian. com Division Chairs/Chefs 548-1252 July/August 1998 Surface Science/Science des surfaces: Dr. Alastair McLean, Queen's University Tel: (613) 545-2709; Fax: (613) 545-6463 E-mail: [email protected]. queensu. ca Theoretical/Théorique: Dr. William Bay Us, University of Windsor Tel: (519) 253-4232 x5041 ; Fax: (519) E-mail: [email protected] 973-7075 B U R E A U DE L ' A C P Senior Councillors/Conseillers supérieur (term ends June 1999): B. C.: Dr. Ahmed Hussein, Univ. of Northern B.C. Tel: (250) 960-6622; Fax: (250) 960-5545 E-mail: [email protected] Alberta: Dr. Helmy S. Sherif, University of Alberta Tel: (403) 492-3523; Fax: (403) 492-0714 E-mail: Sherif@phys. ualberta. ca Saskatchewan & Manitoba: Dr. Robert Pywell, University of Saskatchewan Tel: (306) 966-8526; Fax: (306) 966-6058 E-mail: [email protected] Ontario - Southwest: Dr. Martin Zinke-Allmang, Univ. of Western On. Tel:(519) 661-3986; Fax:(519)661-2033 E-mail: [email protected] Ontario - Central & North: Dr. André Roberge, Laurentian University Tel: (705)675-1151x2234; Fax:(705)675-4868 E-mail: [email protected]. laurentian. ca Ontario - East: Dr. David Lockwood, National Research Council Tel: (613) 993-9614; Fax: (613) 993-6486 E-mail: david. lockwood@nrc. ca Québec - Nord et Ouest: Prof. Sjoerd Roorda, Université de Montréal Tel: (514) 343-2076; Fax: (514) 343-6215 E-mail: [email protected] Québec - Sud et Est: Dr. Alain Villeneuve, Université Laval Tel: (418) 656-3568; Fax: (418) E-mail: a villene @ph y. ula val. ca 656-2623 New Brunswick & Nfld: Dr. Mark Whitmore, Memorial Univ. of Nfld. Tel: (709) 737-8832; Fax: (709) 737-8739 E-mail: [email protected]. ca Nova Scotia & P.E.I.: Dr. Malcolm Butler, St. Mary's University Tel: (902) 420-5827; Fax: (902) 420-5141 E-mail: [email protected]. ca Junior Councillors/Conseillers: (term ends June 2000) B.C.: Dr. Janis McKenna, Univ. of British Columbia Tel: (604) 822-4337; Fax: (604) 822-5324 E-mail: [email protected] Alberta: Mr. Vlad Pasek, Archbishop O 'Leary H. S. Tel: (403) 476-6251; Fax: (403) 472-2579 E-mail: [email protected] Saskatchewan & Manitoba: Dr. Edward Mathie, University of Regina Tel: (306) 585-4576; Fax: (306) 585-4894 E-mail: mathie@meena. cc. uregina. ca Ontario - Central & North: Prof. Aephraim Steinberg, University of Toronto Tel: (416) 978-0713; Fax: (416) 978-2537 E-mail: aephraim@physics. utoronto. ca Ontario - East: Dr. Vernon Koslowsky, Deep River Tel: (613) 584-3760; Fax: (613) E-mail: not available Québec - Nord et Ouest: Dr. Kenneth Ragan, McGill University Tel: (514) 398-6518; Fax: (514) E-mail: ragan@physics. meg ill. ca 584- 1800 398-3733 Québec - Sud et Est: Dr. Denis Morris, Université de Sherbrooke Tel: (819) 821-7073; Fax: (819) 821-8046 E-mail: dmorris@galilee. physique, usherb. ca New Brunswick 8t Nfld: Dr. Abdelhaq Hamza, Univ. of New Brunswick Tel: (506) 458-7923; Fax: (506) 458-4581 E-mail: [email protected] Nova Scotia & P.E.I.: Dr. Derek Lawther, University of P.E.l. Tel: (902) 566-0338; Fax: (902) 566-0420 E-mail: [email protected] Councillors at Large/Conseillers générale: Graduate Students: Ms. Jennifer Lam, University of Ottawa Tel: (613) 993-5765 E-mail: jlam @joule, ph ysics. uo tta wa. ca A t Large: Mr. Mick Lord, Science Applications Int'l Corp. Tel: (613) 563-7242 ; Fax: (613) 563-3399 E-mail: michel.p.lord@cpmx. saic. com Others/Autres: Co-Editors, CJP/Rédacteurs de RCP: Dr. Gordon Drake, University of Windsor Tel: (519) 253-4232 x2656 ; Fax: (519) 973-7075 ; E-mail: [email protected] Dr. Mordechay Schlesinger, Univ. of Windsor Tel: (519) 253-4232 x5041 ; Fax: (519) 973-7075 ; E-mail: [email protected] Editor, PiC/Rédacteur de la Physique au Canada: Dr. Jasper McKee, Univ. of Manitoba Tel: (204) 474-9874 ; Fax: (204) 269-8489 E-mail: mckee@physics. umanitoba. ca Chair,Science Policy Cttee/Chef, Comité de la politique scientifique: Dr. J.C.D. (Douglas) Milton, Deep River, Ontario Tel: (613) 584-2751 E-mail: [email protected] Ontario - Southwest: Dr. Eric Poisson, University of Guelph Tel: (519)824-4120x3949;Fax: (519)836-9967 E-mail: [email protected], uoguelph. ca LA PHYSIQUE AU CANADA juillet à août, 1998 177 C A P OFFICE CAP L A N G U A G E POLICY P O L I T I Q U E D E L ' A C P S U R LA L A N G U E by M. D'Iorio, E.C. Svensson, M.O. Steinitz, and F.M. Ford par M. D'Iorio, E.C. Svensson, M.O. Steinitz, et F.M. Ford As part of the CAP's ongoing efforts to provide better service to all of its members, the CAP has developed and adopted a Language Policy which is given below. Dans le cadre des efforts continuels de l'ACP à offrir de meilleurs services à ses membres, l'ACP amis sur pied et adopté une politique sur la langue que vous trouverez ci-dessous. To help minimize both the increased translation expenses entailed by the adoption of this Language Policy and the number of instances in which messages cannot be transmitted simultaneously in French and English, we are in the process of assembling a list of CAP members who have the necessary language skills and are willing to occasionally produce translations and/or check commercially produced translations. (Because of the scientific and/or political nature of the material normally being translated, commercial translations must be checked and, if necessary, revised by knowledgeable bilingual scientists.) Please inform the CAP Office (tel: (613) 562-5614; e-mail: [email protected]) if you are willing to volunteer to assist the CAP by providing short (up to 200 words) or long translations from English to French or French to English, or if you are willing to check commercially produced English to French or French to English translations. We will make every effort not to overload you with requests. Afin de réduire les coûts croissants de traduction associés à l'adoption de cette politique et le nombre de fois où les messages ne peuvent être transmis simultanément en français et en anglais, nous sommes à assembler une liste de membres de l'ACP qui ont les connaissances linguistiques nécessaires pour traduire ou réviser à l'occasion des traductions professionnelles. (En raison de la nature scientifique et/ou politique des documents normalement traduits, les traductions professionnelles devraient être révisées et, si possible, par des scientifiques bilingues d'expérience.) Veuillez entrer en contact avec le bureau de l'ACP (tél. : (613) 562-5614; cour. élec. : [email protected]) si vous êtes intéressé à aider l'ACP en traduisant de courts (au plus 200 mots) ou longs textes de l'anglais vers le français ou du français vers l'anglais, ou si vous voulez réviser des traductions professionnelles de l'anglais au français ou du français vers l'anglais. Nous nous efforcerons de ne pas vous submerger de demandes. LANGUAGE POLICY POLITIQUE SUR LA LANGUE The Canadian Association of Physicists aspires to communicate with its members in whichever of Canada's two official languages the member prefers. We set out here the language policy that will guide us in the communications with our members as regards: L'Association canadienne des physiciens et physiciennes aspire à communiquer avec ses membres dans les deux lar gues officielles du Canada, au choix du membre. Nous vous présentons cidessous la politique sur la langue qui nous guidera lors de nos contacts avec nos membres en ce qui concerne les : 1. 2. 3. 1. 4. 5. 6. General messages sent by e-mail to the membership. General mailings to members from the CAP Office. News items from the CAP Executive or the CAP Office published in Physics in Canada. The Annual 'Report on Activities'. Items posted on the CAP website. Posters General Messages Sent by E-mail to the Membership 2. 3. 4. 5. 6. Messages généraux expédiés aux membres par courrier électronique. Envois généraux postés aux membres par le bureau de l'ACP. Nouvelles de l'exécutif ou du bureau de l'ACP publiées dans La Physique au Canada. Rapport annuel des activités. Informations affichées sur le site Web de l'ACP Affiches Messages généraux expédiés par courrier électronique Ideally, messages sent by the CAP office will be sent simultaneously in both official languages. Short messages will normally be sent in both languages to the entire e-mail list. Long messages will normally be sent separately in English and French, to e-mail lists constructed using the language preference stated by the individual members. Attachments to the message (e.g., information items from sources other than the CAP, letters that have been sent to politicians, etc.) will normally be provided in the language in which they were produced. Idéalement, les messages envoyés par le bureau de l'ACP le seront simultanément dans les deux langues officielles. Les courts messages seront normalement envoyés à toute la liste électronique dans les deux langues. Les messages plus longs seront normalement envoyés séparément en anglais et eri français aux listes électroniques montées d'après la préférence de langue inscrite sur le formulaire de renouvellement. Les documents attachés aux messages (p. ex. les nouvelles provenant d'une source autre que l'ACP, les lettres envoyées aux politiciens, etc.) seront normalement envoyés dans la langue originale. In practice, it will not always be possible to send messages simultaneously in both languages. Often the material to be transmitted is of a time-sensitive nature and the CAP Executive deems that it needs to go out as soon as it becomes available. In such cases, the message will be sent in the first-available language, with a brief up-front message in the other language to explain that it will follow in that language as soon as the translation is completed. We will normally send the initial message to the entire En pratique, il n'est pas toujours possible d'envoyer simultanément des messages dans les deux langues. Il arrive parfois que l'information à transmettre est d'une certaine urgence et l'exécutif de l'ACP préfère qu'elle soit envoyée aussitôt que possible. Dans de tels cas, le message sera envoyé dans la première langue disponible avec un bref message d'ouverture dans l'autre langue expliquant que le message sera envoyé dans l'autre langue aussitôt la traduction terminée. Nous enverrons normalement le message initial à toute la liste électronique et la 178 PHYSICS IN CANADA July/August 1998 BUREAU DE L ' A C P e-mail list and the follow-up translation only to the e-mail list corresponding to that language preference. traduction à suivre qu'à la liste correspondant à cette préférence de langue. General Mailings f r o m the CAP O f f i c e Envois généraux postés par le bureau de l'ACP These include things like the membership-renewal package and the slate of nominations for new Council members. In general, everything will be provided in both French and English though, to save costs, the material may be partially or completely sorted by language and sent to members in accordance with their stated language preference. Ces envois comprennent la trousse de renouvellement d'adhésion et la liste des candidatures pour les nouveaux membres du Conseil. En général, tout sera fourni en anglais et en français quoi que, pour des raisons économiques, le matériel sera partiellement ou complètement trié par langue et envoyé aux membres suivant la préférence de langue indiquée. N e w s Items f r o m the CAP Executive/Office in 'Physics in Canada' N o u v e l l e s de l'exécutif et du bureau de l'ACP publiées dans 'La Physique au Canada' Except under the most extenuating of circumstances, these will appear together in both French and English. Sauf exception, toutes les nouvelles seront publiées en anglais et en français. The Annual 'Report o n Activities' Le rapport annuel des activités Traditionally, only the 'President's Report' at the front has been provided in both languages. The different Divisions, Committees, etc. may provide their reports in either English or French, but have not been required to provide translations. To provide the entire document in both languages could represent a major expense for the CAP, though we ultimately hope to do so since this document is now being posted on the CAP website, which we plan to make fully bilingual (see below). In future, we will ask the Divisions, Committees, etc. to provide their reports in both languages, since there will usually be a member of the Division, Committee, etc. who can provide the translation. If a translation cannot be provided, and it is decided that the 'Report on Activities' must be available in both languages, translation costs will be borne by the Association. Selon la tradition, seul le rapport du président au début du document est produit dans les deux langues. Les différents Comités, Divisions, etc. peuvent fournir leur rapport en français ou en anglais, mais ne sont pas requis de le traduire. La production du document entier dans les deux langues représenterait un coût énorme pour l'ACP, quoi que nous espérons le faire puisque ce document est maintenant affiché sur le site Web de l'ACP, qui éventuellement deviendra complètement bilingue (voir ci-dessous). À l'avenir, nous demanderons aux Divisions, Comités, etc. de présenter leur rapport dans les deux langues puisqu'il y a d'habitude un membre du Comité, de la Division, etc. qui peut le traduire. Si une traduction n'est pas fournie et qu'il est décidé que le rapport des activités doit être offert dans les deux langues, l'Association assumera les coûts de traduction. Items Posted on the CAP Website Informations affichées sur le site W e b de l'ACP Ultimately, we plan to have French and English in parallel, i.e., you will be able to click on either English or French as you enter the CAP website. Again, we will not necessarily provide translations of attachments (see 1. above). Nous planifions éventuellement avoir le français et l'anglais en parallèle, p. ex. en entrant dans le site Web de l'ACP, vous pourrez cliquer soit sur l'anglais soit sur le français. Nous vous rappelons que nous ne fournirons pas nécessairement la traduction des documents attachés (voir point 1. ci-haut). We hope to achieve English and French CAP websites by the end of 1998, but this will depend somewhat on the cost involved and on our ability to recruit someone to do the necessary work. In the meantime, we will post as much material as possible in both languages. Sometimes material deemed to be time sensitive will be posted in one language even though there is a delay with the translation. Notre objectif est que le site Web de l'ACP soit en français et en anglais avant la fin de 1998, mais cela dépendra du coût et de notre capacité à embaucher quelqu'un pour accomplir le travail. En attendant, nous afficherons le plus d'informations possibles dans les deux langues, quelques fois avec un délai de traduction si l'information est jugée pressante. Posters Affiches Items from the CAP that are meant to be posted in public places, like the Congress Poster and the poster advertising free student memberships, will either be bilingual (most desirable) or available in both French and English versions. In the latter case, there may again sometimes be a delay in availability for time-sensitive items like the Congress Poster, which is traditionally produced by the Local Organizing Committee and so is not under the direct control of the CAP Office. Les informations de l'ACP qui doivent être affichées dans des endroits publics, telles que l'affiche du congrès et l'affiche sur les adhésions gratuites pour les étudiants, seront soit bilingue (préférablement) soit en versions anglaise et française. Ces dernières pourraient également être retardées en raison de l'urgence de l'information, comme l'affiche du Congrès qui est normalement produite par le comité organisateur local et donc n'est pas directement contrôlée par le bureau de l'ACP. Additional Remarks Commentaires supplémentaires The CAP does not intend to require that its Divisions, Committees, etc. communicate with their members in both languages. L'ACP ne requiert pas ses Divisions, Comités, etc. à communiquer avec ses membres dans les deux langues. LA AU CANADA juillet à août, 1998 179 C A P OFFICE / CALENDAR As especially concerns 1. above, there are two main reasons that messages cannot always be transmitted simultaneously in both French and English. The first is that the members of the CAP Executive who produce the messages are normally volunteers, with demanding other jobs, who simply may not be able to produce the message in time to have it translated before it must go to the membership. The second reason is that the translation often takes considerably longer than anticipated. Some of the (scientific, political...) material that must be translated is quite tricky to translate, and commercial translators of sufficient skill are not always available on short notice. We always try to have the translation checked by a bilingual physicist, and often she/he disagrees strongly with the translator. We have, in the past, frequently been criticized for sending out 'sloppy' translations, and we are trying hard to avoid this. We hope that our members will appreciate these constraints, and be sympathetic when the English and French versions are not available simultaneously. 1998 April 15 Endorsed by the CAP Council by e-mail in 1998 April, following approval in principle at the 1998 March 28 Council meeting. En ce qui concerne le point 1. ci-dessus, il existe deux raisons importantes pour lesquelles les messages ne peuvent pas toujours être envoyés simultanément en français et en anglais. La première raison est que les membres de l'exécutif de l'ACP qui produisent ces messages sont normalement des bénévoles, occupant d'autres emplois exigeants, et ne peuvent parfois produire le message assez rapidement pour qu'il soit traduit avant d'être envoyé aux membres. La seconde raison est que la traduction est beaucoup plus longue à produire qu'anticipé. Certaines des traductions (scientifiques, politiques...) sont quelque peu épineuses et les traducteurs de talent ne sont pas toujours disponibles à la dernière minute. Nous essayons toujours de faire réviser la traduction par un physicien ou une physicienne bilingue et il arrive souvent qu'il ou elle soit en total désaccord avec le traducteur ou la traductrice. Nous avons souvent été critiqué dans la passé d'avoir émis de mauvaises traductions et nous nous efforçons de les éviter. Nous espérons que nos membres seront sensibles à ces contraintes et compréhensifs lorsque les versions française et anglaise ne seront pas prêtes simultanément. Le 15 avril 1998 Approuvée par le Conseil de l'ACP par courrier électronique en avril 1998, à la suite de l'approbation en principe à la réunion du Conseil le 28 mars 1998. CALENDAR / CALENDRIER 1998 AUGUST 3-7 16th International Conference on Atomic Physics, Windsor, Ontario. Contact: G.W.F. Drake, Department of Physics, University of Windsor, Windsor, Ont N9B 3P4. Tel: (519) 253-4232 x2647; Fax: (519) 9737075; e-mail: A36@server. uwindsor.ca. 1999 JUNE Canada V6T 1Z1; Fax: (604) 822-2847. 2000 JULY 23-28 World Congress (WC 2000) on Medical Physics and Bioengineering, Chicago, Illinois, USA. For more information please contact: William Hendee by email at whendee@post. its.mcw.edu 6-9 1999 CAP Conference, Univ. of New Brunswick, Fredericton, NB; email: CAP@physics. Ottawa.ca 1999 JULY 3-7 IV Liquid Matter Conference (IV LMC), Granada, Spain. For more information contact Prof. Pedro Tarazona, Departamento de Fisica Teôrica de la Materia Condensada, Universidad Autônoma de Madrid, E28049 MADRID (Spain), E-mail: [email protected]; Fax: + + 3 4 1 3974950 26-30 180 6th International Conference on the Structure of Surfaces (ICSOS-6), Vancouver, British Columbia, Canada. Contact: K.A.R. Mitchell, Department of Chemistry, University of British Columbia, Vancouver, BC, PHYSICS IN CANADA FUTURE CAP CONFERENCES CAP 1 9 9 9 Annual Congress, 1 9 9 9 J u n e 6 - 9 . U n i v e r s i t y of New Brunswick. CAP 2 0 0 0 Annual Congress, 2 0 0 0 June 4 - 7 , York University. CAP 2 0 0 1 Annual Congress, 2 0 0 1 J u n e 1 7 - 2 0 , U n i v e r s i t y of V i c t o r i a . July/August 1998 APS MEETINGS - 1998 and Beyond The APS Calendar of Meetings can be found on the APS Home Page under Meetings Information, address: http://www.aps.org. Gaseous Electronics Conference, October 19-22, 1998, Maui, Hawaii Division of Nuclear Physics, October 28-31, 1998, Santa Fe, New Mexico Division of Plasma Physics, November 16-20, 1998, Miami, Florida Division of Fluid Dynamics, November 22-24, 1998, Philadelphia, PA Division of Particles and Fields, January 6-9, 1999, Log Angeles, CA, e-mail: [email protected] APS CENTENNIAL MEETING, March 20-26, 1999, Atlanta, Georgia 2000 March Meeting, March 20-24, 2000, Minneapolis, MN 2001 March Meeting, March 12-16, 2001, Seattle, WA 2002 March Meeting, March 19-22, 2002, Indianapolis, IN L A P O L I T I Q U E SCIENTIFIQUE SCIENCE P O L I C Y / L A POLITIQUE SCIENTIFIQUE 1998 NSERC REALLOCATION PROCESSUS EXERCISE (Reprint of a letter sent to CAP members by e-mail on 1998 July 7) DE RÉALLOCATION 1998 (Reproduction d'une communiqué envoyé aux membres de l'ACP par courrier électronique le 7 juillet, 1998) C h e r s / c h è r e s collègues et amis, Dear Colleagues a n d Friends, I h o p e that y o u have h a d a chance to visit the NSERC website ( h t t p : / / w w w . n s e r c . c a ) to h a v e a look at the results of the 1998 reallocation exercise. J'espère que vous avez tous eu l'occasion d'étudier lea résultats d u processus de réallocation 1998 sur le site WEB d u CRSNG (http:www.nserc.ca). I believe that w e can take a great deal of satisfaction f r o m the results. Je crois q u e n o u s p o u v o n s trouver u n e grande mesure de satisfaction d a n s ces résultats. In contrast to the previous reallocation exercise, w e have received essentially u n a n i m o u s positive feedback. This m a y be seen in the general c o m m e n t s f r o m T o m Brzustowski in the "Message f r o m the President" at the head of the NSERC Report o n the 1998 Reallocations Exercise, to b e f o u n d o n the website, in the specific c o m m e n t s m a d e by Liz Boston a n d Jean Lengelle in their m e m o to CORG on "Response to the r e c o m m e n d a t i o n s of the Review of C a n a d i a n Academic Physics", in the international assessors' evaluations of C a n a d i a n physics in the Review, a n d in the financial results of the reallocation exercise for o u r c o m m u n i t y . En comparaison avec la dernière réallocation, n o u s avons reçu des compliments d e toute part. Ceci est bien clair dans le "Message d u Président", T o m Bruzustowski à l'entête du r a p p o r t d u CRSNG s u r la réallocation de 1998, les commentaires d e Liz Boston et Jean Lengelle dans leur m é m o au CORG ("Réponse au r e c o m m a n d a t i o n s de la Revue de la Physique A c a d é m i q u e Canadienne"), les évaluations des arbitres internationaux d a n s la Revue, et les résultats financiers de la réallocation p o u r notre communauté. We can be justly p r o u d of the w a y in w h i c h the Review w a s conducted, the assessments it contains f r o m the International Assessors, a n d the w o r k of the physics Reallocation Steering C o m m i t t e e s in p r e p a r i n g their submissions to NSERC. N o u s p o u v o n s être très fiers de la façon dont a été menée la Revue, des évaluations des arbitres internationaux et d u travail acharné de nos comités de direction p o u r la réaffectation au cours de la préparation de leurs soumissions au CRSNG . We o w e a great debt of gratitude to the m e m b e r s of the Main Committee, the Discipline Subcommittees, a n d the International Assessors w h o u n d e r t o o k the Review of C a n a d i a n Academic Physics. In particular, the efforts of Paul Vincett, as NSERC physics g r o u p chair a n d as a u t h o r of the s t u d y on Economic Impact, w e r e especially important. I w o u l d also like to individually t h a n k Bill Halperin, the chair of the Main Committee, as well as G o r d o n Drake, Faqir K h a n n a , Bev Robertson, Pekka Sinervo, Mike Thewalt a n d Ted Llewellyn. I h o p e that they will convey o u r g r a t i t u d e to the other m e m b e r s of their committees a n d to the assessors. N o u s devons u n e fière chandelle aux m e m b r e s d u comité principal, sous-comités disciplinaires, et arbitres internationaux qui ont a s s u m é la revue de la physique universitaire canadienne. En particulier, les efforts de Paul Vincett, c o m m e chef de g r o u p e des comités d e physique du CRSNG et c o m m e auteur de l'étude de l'impact économique, sont particulièrement dignes de notre reconnaissance. Je voudrais, aussi remercier individuellement Bill Halperin, chef d u comité principal, ainsi q u e G o r d o n Drake, Faqir Khanna, Bev Robertson, Pekka Sinervo, Mike Thewalt et Ted Llewellyn. J'espère qu'ils transmettront notre gratitude aux autres m e m b r e s de leurs comités et aux arbitres. We also extend o u r w a r m e s t t h a n k s to the m e m b e r s of the physics Reallocation Steering C o m m i t t e e s chaired by: Ray Carlberg - Space, A s t r o n o m y a n d General Relativity (GSC 17) Pekka Sinervo (co-chair Shelley Page) - Subatomic Physics (GSC 19) Jeff Y o u n g - C o n d e n s e d Matter Physics (GSC 28) G o r d o n D r a k e - General Physics (GSC 29) N o u s remercions de tout coeur les m e m b r e s des comités de direction p o u r la réaffectation qui ont été présidés par: Ray Carlberg - recherche spatiale et astronomie (CSS17) Pekka Sinervo et Shelley Page - physique subatomique (CSS19) Jeff Young - physique de la matière condensée (CSS 28) G o r d o n Drake - p h y s i q u e générale (CSS 29) LA PHYSIQUE AU CANADA juillet à août, 1998 181 S C I E N C E POLICY for all of their hard work in preparing the submissions which were, of course, the input to the Reallocation Exercise and the basis on which physics was evaluated. (The full memberships of the Steering Committees, as well as the complete Reallocation Submissions, can be found on the NSERC website (http://www.nserc.ca)). Ils ont travaillé avec acharnement pour préparer leurs soumissions à partir desquelles la physique a été évaluée et les fonds du CRSNG ont été réaffectés. Vous trouverez une liste complète des membres des comités de direction ainsi que les soumissions pour la réaffectation en consultant le site Internet du CRSNG (http://www.nserc.ca). You can do your own calculations on the data presented on the NSERC website, but the simplest one is to just take the ratio of the new budget to the 1998-99 budget. A rank ordering of the 19 committees (with institutes lumped into the appropriate committees)is shown below. Other orderings and calculations are possible, but the results for physics are not very different. On the basis of the original 'zero-sum' reallocation plan, physics, as a whole, got out roughly what it put in. On the basis of the increased NSERC budget, physics, as a whole, is roughly in the middle of the pack. We did not lose money and some of the physics committees made some gains. Vous pouvez, vous-même, faire les calculs sur les données présentées sur le site WEB du CRSNG, et le plus simple calcul est de prendre le rapport du nouveau budget, au budget de 1998-99. Un tableau des 19 comités (incluant les instituts dans les comités appropriés) est dressé ci-dessous. D'autres tableaux et calculs sont possibles, mais les résultats pour la physique ne sont pas très différents. D'après le plan original de la réallocation (somme = zéro), la physique a reçu à peu près ce qu'elle a mis dans la caisse. Par rapport au budget augmenté du CRSNG, la physique se situe au milieu du groupe de comités. Nous n'avons pas perdu beaucoup d'argent, et quelques comités en ont gagné un peu. Within the parameters set for the reallocation process, I believe that our community presented an excellent case in the Review document, that the assessors gave a very positive and complimentary assessment of Canadian physics and physicists, and that we succeeded in having a fair reallocation of funds to our community. Compte tenu des paramètres régissant le processus de réallocation, je crois que notre communauté a présenté un cas excellent dans la Revue, que les arbitres ont donné une évaluation très positive et élogieuse de la physique au Canada, des physiciens et physiciennes canadiennes, et que nous avons réussi à obtenir une juste réallocation pour notre communauté. Congratulations to all, and thanks again to all who worked so hard on this important project. Félicitations à tous, et encore merci de l'effort remarquable fourni par tous ceux qui ont oeuvré pour le succès de cet exercice de réallocation. Sincerely, Michael Steinitz, President, CAP Sincèrement, Michael Steinitz, président, ACP Steering Committee 182 New Budget/ 98-99 Budget Steering Committee New Budget/ 98-99 Budget 1. Electrical/Computer Engineering 1.22 11. Chemistry 1.16 2. Cell Biology/Mol. & Dev. Gen 1.22 12. General Physics 1.15 Physics 3. Comp/lnformation Sciences 1.21 13. Subatomic Physics 1.15 Physics 4. Statistical Sciences 1.19 14. Plant Biology & Food Science 1.15 5. Psychology 1.19 15. Animal Biology & Physiology 1.10 6. Mathematics 1.18 16. Solid & Environmental Earth Sciences 1.08 7. Evolution and Ecology 1.17 17. Industrial Engineering 1.08 8. Condensed Matter Physics 1.17 Physics 18. Mechanical Engineering 1.07 9. Chemical & Metallurgical Engineering 1.16 19. Civil Engineering 1.04 10. Space and Astronomy 1.16 Physics PHYSICS IN CANADA J u l y / A u g u s t 1998 IN MEMORIAM I N MEMORIAM PAUL GAUNT> 1 9 3 2 - 1 9 9 8 Paul G a u n t , a Professor in the D e p a r t m e n t of Physics a n d A s t r o n o m y at the University of Manitoba, died in January of this year, h a v i n g f o u g h t the progressive effects of multiple sclerosis for m o r e than a decade. A celebration of his life w a s held s u b s e q u e n t l y in St. John's College on the University of Manitoba c a m p u s w h i c h w a s a t t e n d e d by Margaret, his wife of m a n y years, his family a n d m a n y f r i e n d s a n d colleagues. Paul joined the University in 1968 as an Associate Professor, having already entered the academic ranks at the University of Sheffield. Prior to his going on long term disability in 1988, Paul established a n active research g r o u p w o r k i n g in the OTTO HAUSSER, area of hard magnetic materials publishing both experimental a n d theoretical p a p e r s on the influence of d o m a i n wall pinning on such properties. As a result of a recent resurgence of interest in this area, this work has been well referenced over the past five or so years. In the area of teaching, he introduced a pair of g r a d u a t e courses which were a m o n g s t the first in this d e p a r t m e n t to have an interdisciplinary structure; the courses, entitled "Diffraction Theory a n d Techniques" stressed the c o m m o n themes that existed in this area between physics, metallurgy and mineral crystallography. Paul will be r e m e m b e r e d for his w a r m and gentle personality; he will be missed as a valued colleague and for his generous dispensation of friendship in the broadest terms. G w y n Williams 1937-1998 Otto H a u s s e r died in Vancouver, o n March 5,1998, after a lengthy a n d c o u r a g e o u s battle with m y e l o m a . His death is an e n o r m o u s loss to TRIUMF, to C a n a d i a n physics a n d to his m a n y friends a n d a d m i r e r s a r o u n d the globe. H a u s s e r w a s b o r n in Schwabach, G e r m a n y , on December 9,1937 a n d received his university training at Erlangen a n d at Heidelberg before s p e n d i n g t w o postdoctoral years at Oxford. H e came to Chalk River in 1966. In 1983 he accepted a joint a p p o i n t m e n t at Simon Fraser University a n d TRIUMF. His o u t s t a n d i n g achievements in m o r e than three decades of research in C a n a d a have h a d few equals. It w a s H a u s s e r ' s strong personal characteristics w h i c h d r o v e his science a n d m a d e a n indelible impression on the m a n y physicists w h o interacted w i t h him. H e w a s extraordinarily intense a b o u t physics, he h a d e n o r m o u s creative impulses a n d the highest s t a n d a r d s w h i c h he i m p o s e d relentlessly o n himself a n d on his collaborators. For him, each n e w experiment presented a personal challenge to u n d e r s t a n d every aspect of the physics in complete detail. This extraordinary attention to detail w a s combined with a u n i q u e flair for elegant presentation of the essential experimental results. Wherever Hausser headed great science followed. Otto H a u s s e r led. In his earliest days in Franconia he could not u n d e r s t a n d w h y his parents w e r e worried w h e n he led a friend into the deepest recesses of a cave, and became temporarily lost. H e mastered theoretical ideas and experimental techniques w i t h equal ease. At Chalk River Nuclear laboratories he w a s the intellectual leader of a g r o u p which exploited the Chalk River t a n d e m accelerator(now sadly departed) to explore mesonic effects on the magnetic m o m e n t s a n d other m o m e n t s of heavy nuclei. A series of brilliant p a p e r s emerged, with David W a r d , Ian T o w n e r a n d other Chalk River colleagues, which helped to clarify the limits of the nuclear shell model. T h r o u g h o u t his career Otto c h a n g e d fields easily to a c c o m m o d a t e n e w science opportunities. O n his move to Vancouver he seized the o p p o r t u n i t y to probe the collective m o d e s of nuclear excitation using the m e d i u m energy proton a n d n e u t r o n b e a m s of TRIUMF. Otto understood that polarization observables w e r e crucial to achieve LA PHYSIQUE AU CANADA juillet à août, 1998 183 IN M E M O R I A M understanding of the hadronic interactions in terms of nucléon response functions. He developed a focal plane polarimeter for the TRIUMF MRS proton spectrometer, as well as a superb polarized 3He target using the latest laser technology available. He then exploited these significant technical achievemnts and combined them with other laboratory developments - such as high quality proton beams and a unique facility for charge exchange reactions to attack a wide range of ideas generally involving the nuclear spin and isospin response. This response was expected to reveal quark degrees of freedom and thus go beyond the nuclear shell model. However, the shell model continued to triumph. The 3He target, as the next best thing to a pure neutron target, was exploited not only for studies of the nuclear few-body system but also for work with pions and muons. These pioneering efforts also led Otto to initiate TRIUMF's involvement in the HERMES experiment at HERA in Hamburg. More recently as TRIUMF changed directions, in the post-KAON era, toward facilities for radioactive beams, ERNEST R. KANASEWICH, 1931 He returned as faculty to the Department of Physics at the University of Alberta in 1963 as an Assistant Professor rising to full Professor of Physics in 1971. Aside from a one year sabbatical as a Research Associate Professor at the Seismological Laboratory at the California Institute of Technology, he remained at the University of Alberta until his retirement in 1996. Despite a severe pulmonary illness, PHYSICS IN CANADA Hausser's other great lifelong intellectual passion was his music. He was an excellent cellist, one of the best in Vancouver, and had warm interactions with many through chamber music. For those of us who knew him it will not be possible to forget Hausser or his accomplishments and especially his driving force for excellence. In some sense he will always be towering over us. Peter Jackson, Jean-Michel Poutissou, Erich Vogt -1998 Ernest R. Kanasewich, a pioneer in the development of active source seismology as a tool in the exploration of the earth's crust and uppermost mantle, died in Edmonton, Alberta on June 19, 1998 at the age of 67. Born in rural Saskatchewan, Ernie received his B.Sc. in Physics at the University of Alberta in 1952. He was introduced to Geophysics when hired as a seismologist at Geophysical Services Incorporated, a subsidiary of Texas Instruments. He worked in both Canada and the Middle East for six formative years gaining considerable practical knowledge of the capabilities of seismic methods. He returned to the University of Alberta to complete a M.Sc. in Physics in 1960 on magnetic methods in the nascent Geophysics program begun under Professor George Garland. He obtained his Ph.D. with Professor Bill Russell in 1962 on newly developed methods of isotopic lead age dating. 184 Otto had another complete change of fields and headed a very interesting effort using laser techniques to trap radioactive neutral atoms for fundamental studies of weak interactions. This TRINAT project continues to show great promise. It was conceived by Otto and his ide as remain important in its present development. All of his TRIUMF colleagues marvelled at how Otto drove himself for TRINAT physics, in late 1997, when he was racked and bent by his terminal illness. J u l y / A u g u s t 1998 Ernie continued his research and writing unt il the end, he was scheduled to present a scientific paper ai the Canadian Society of Exploration Geophysicists the day before his passing. He was heavily involved in the Department having served as the associate Chair during the period from 1967 to 1973 and as acting Chair from 1973 to 1974. He served as Chair over the very difficult period of severe funding cutbacks from 1991 to 1996. He was also Director of the Institute of Earth and Planetary Physics from 1991 to 1993 instigating its name change to the more accurately descriptive Institute of Geophysics, Meteorology, and Space Physics. Of his many awards, perhaps the most notable are his election to the Royal Society of Canada in 1975, his honorary memberships in both the Canadian Society of Exploration Geophysicists (1983) and the Society of Exploration Geophysicists (1994), the J. Tuzo Wilson medal from the Canadian Geophysical Union (1989), and most recently the Canadian Association of Physicists Gold Medal (1998) officially awarded during this year's CAP Congress in Waterloo. Ernie's career spanned a time of great upheaval in our understanding of the earth as a planet including the grudging acceptance of plate tectonics as a working paradigm in the early 1970's. The tools of the experimental seismologist grew dramatically at the same time. Ernie's healthy skepticism of nay-sayers based soundly on his IN M E M O R I A M years of industrial field experience p u s h e d him to take risks such as the first d e v e l o p m e n t of a set of portable, b r o a d b a n d digital s e i s m o g r a p h s in 1970. Efforts at the University of Alberta to p u s h the technology of the d a y resulted in the first observations of d e e p crustal a n d u p p e r mantle reflections u s i n g explosive sources as early as 1965. Such observations w e r e theoretically t h o u g h t impossible but Ernie u n d e r s t o o d the p r o b l e m to be one of signal versus noise d u r i n g acquisition. Intellectually, these crucial observations p r o v i d e d the impetus for m a n y of the present d a y d e e p crustal seismic investigations. The most notable of s u c h projects is the C a n a d i a n LITHOPROBE transects of w h i c h Ernie w a s an early, a n d key, p r o p o n e n t . Ernie u n d e r s t o o d the importance of collaboration b e t w e e n institutions, especially in the context of the limited f u n d i n g available for research in C a n a d a , w a s a p r i m a r y instigator of a n u m b e r of the transects, a n d p r o v i d e d substantial resources to field p r o g r a m s of other transects. Technically, this w o r k led to Ernie's writing of his p o p u l a r text 'Time Sequence Analysis in Geophysics' the first edition of w h i c h a p p e a r e d in 1973. In the geophysics c o m m u n i t y , this w a s the right book written at precisely the right time. It presented an overview of digital m e t h o d s in signal analysis just as u s e f u l c o m p u t a t i o n a l p o w e r w a s becoming available to researchers in academia and industry. This book w a s a necessary part of every geophysicist's library a n d w e n t t h r o u g h three editions with translation into Russian. The book helped s p u r the revolution in seismic reflection imaging of the earth which is today a multi-billion dollar w o r l d w i d e industry. Ernie m a d e important contributions in n u m e r o u s other are as of seismology and geodynamics. Of note, is his 1972 study, described in N a t u r e , of a n o m a l o u s seismic arrivals related to the core-mantle b o u n d a r y beneath Hawaii. This problem is today being revisited in attempts to better u n d e r s t a n d the sources of mantle plumes. His initial ideas on the scale of convective cells within the mantle (1976) w e r e prescient of the results provided by m o d e r n global tomographic images. H e also carried out some of the first field tests of seismic t o m o g r a p h y which w a s used to image a steam-heated heavy oil reservoir. He u n d e r s t o o d well the importance of ever increasing p o w e r f u l computational resources a n d u s e d these to full a d v a n t a g e in modelling a n d inversion of complex seismic w a v e responses through heterogenous structures long before the elevation of computational physics to its postion between experiment and theory. He published over 100 p a p e r s and authored two additional books: Seismic Noise Attenuation (1990) and Seismic Imaging of In Situ Bitumen Reservoirs and the Properties of Porous Media (1998) which, sadly, he will not see. Ernie supervised 20 Ph.D. a n d 15 M.Sc. theses. His students, w h o s e careers have taken them to at least four continents, have attained high individual recognition at a n u m b e r of Universities a n d as scientific and business leaders within the petroleum exploration industry. His counsel and fresh a p p r o a c h e s to geophysical observations will be sorely missed by his f o r m e r students and colleagues at the University of Alberta. H e is survived by his wife, Elaine, their children A n t h o n y a n d Patricia, his father Max, a brother, a n d t w o sisters. Douglas R. Schmitt and Helmy S. Sherif 1998 SUSTAINING MEMBRES / MEMBRES DE SOUTIEN 1998 as at 1998 June 30 / jusqu'à le 30 juin 1998 A. John Alcock J. Brian Atkinson Pierre André Bélanger C. Bruce Bigham Bertram N. Brockhouse Laurent G. Caron Allan I. Carswell Robert L. Clarke Walter G. Davies Gerald Dolling Gordon W.F. Drake Earl J. Fjarlie Brian C. Gregory Elmer H. Hara Akira Hirose Betty Howard Roger Howard Allan E. Jacobs J. Larkin Kerwin James D. King Peter Richard Kry Ron M. Lees Roger A. Lessard A. David May J.S.C. (Jasper) McKee Ann C. McMillan Jean-Louis Meunier J.C. Douglas Milton LA PHYSIQUE AU CANADA Allan A. Offenberger Roger Phillips Satti Paddi Reddy Beverly E. Robertson John M. Robson Alec T. Stewart G.M. Stinson Boris P. Stoicheff Eric C. Svensson John G.V. Taylor Henry M. van Driel Paul S. Vincett Erich Vogt juillet à août, 1998 185 OPINION (ANTI-SCIENCE ATTITUDES...) ANTI-SCIENCE ATTITUDES, CONSTRUCTION O F KNOWLEDGE A N D OBJECTIVITY I N SCIENCE by: Ashok K. Vijh, O.C., F.R.S.C. epistemology". A basic tenet of all these labels is that all knowledge is socially constructed and culturally n a recent excellent essay, Bard has raised the biased and serves the ideology and hidden agenda of timely issue of anti-science attitudes in our the dominant group. The main thrust of these society [1]. In fact, the problem is so pervasive movements is to mount an attack on the notion of that, many books, symposia and scholarly collections objective knowledge in general and on the methods of essays appear every year giving rise to a "post modernist" industry devoted and approaches of science in to the demolition of the particular. The icons of this concept of objective subversion of science are, A variety of anti-science attitudes knowledge in science 12,3 '. among others, Foucault, prevalent in our society and in the Scientists have, in general, Derrida and Feyerabend: they academe are analyzed with a focus to not paid much attention to proclaim that all knowledge delineate the nature of valid objective this nefarious attack on the is culturally constructed and knowledge in science. validity of scientific that such constructions, knowledge, with the including superstitious beliefs of different cultures, have equal value. consequent result that our society in general has become saturated with a large variety of anti-science practices and ideas. Drawing u p o n our previous The debate on this issue has polarized into two essay' 4 ' and inspired by the exposition of Bard' 1 ', w e extreme camps: scientific positivism, and, propose to elucidate here the various strands of this constructivist epistemology. Let us define these two anti-science attitude, and, comment u p o n the nature approaches to the nature of knowledge and examine of objective knowledge. their implications, limitations and validity; also the focus here is explore what each of the approaches has to offer to the attainment of objective knowledge. ATTACKS O N SCIENCE I The most obvious attacks on science arise from a variety of anti-science clap-trap embedded in the "beliefs" and "world-views" of the lay public and the media w h o propagate it: some examples are para-psychology, faith-healing, water-divining, astrology, aliens and UFOs, all kinds of paranormal and super-natural "phenomena", myths about the origin of the universe and much else in the religious fundamentalism of m a n y varieties, both in the Eastern and Western cultures. A more insidious form of anti-science attitude arises from "serious scholarship" as practised on our major university campuses u n d e r a variety of "respectable" "Philosophical" movements: "deconstruction" (started by Michel Foucault); "relativism"; "feminine epistemology"; "post-modernism"; "constructivist 186 PHYSICS IN CANADA July/August 1 9 9 8 SCIENTIFIC POSITIVISM A N D CONSTRUCTIVIST EPISTEMOLOGY Scientific positivism is the ideology that claims that scientists discover the truths of nature by the "scientific method". At the very least this is an extremely simplistic approach since all scientific experiments (and their interpretation) are theory-laden: there are no facts independent of theory. As argued previously' 5 ' there is no such thing as experimental facts: one has only experimental observations whose validity is partial, contextual and temporary since its value is limited by the currently Ashok Vijh is located at the Institut de recherche d'Hydro-Québec, in Varennes, Quebec: OPINION available experimental methods and by the bias of the theoretical framework used to design the experiments and interpret the data. In other words, experiments yield data and not facts; and all data are of provisional validity till sharper theoretical frame-works and more sophisticated experimental methods give rise to more penetrating studies. To take an analogy, Nature is like an onion and successively more sophisticated means of investigating Nature only result in peeling off another layer: one never reaches the centre of the onion. To take a concrete example, let us consider gravitation. Newton's interpretation of gravitation did not become "invalid" with the availability of Einstein's theory of relativity. Newton's law of gravitation is still valid in all contexts except those in which the objects are travelling at or near the speed of light. So, science does not really discover "objective truths" but rather successively closer approximations of the descriptions of natural phenomena allowed by the context (e.g., objects travelling near or much below the speed of light), currently available experimental methods and the theoretical f r a m e w o r k under-pinning those experiments. Also, scientists are assumed to be objective seekers after truth etc.161. This must be interpreted to mean that scientists, by and large, tend to explore natural phenomena by avoiding the vitiation of their pursuit by commercial motivation, self-interest or ambition, although this would appear to be an idealized version. This "seeking of objective truth" should not, however, be interpreted as the claim that scientists have a monopoly route to truth - whatever that truth may mean; however, they do get as close to the objective knowledge of the real world as one can get, as will be shown below. Also the so-called "scientific method" in which the requirement that a scientist actively seeks to disprove an idea before presenting it as a possible new truth is also simplistic. With this narrow definition, it would appear that P.A.M. Dirac, one of the towering figures of science in this century, was not practising the scientific method w h e n he claimed, "it is more important to have beauty in one's equations than to have them fit experiment" 17 '. Science is not just setting-up experiments and checking data against theories and hypotheses one may be currently ( A N T I - S C I E N C E ATTITUDES...) clinging to: it involves intuition, imagination, bold "leaps of thought" experiments and much else; the so-called scientific method changes with the style of the scientist. The application 181 of constructivist epistemology to science in which all knowledge is socially constructed to make sense of experience has some validity in the sense that the "objectivity" of scientific knowledge is really "inter-subjectivity" in which people (i.e., scientists) trained in a given area or discipline agree as to what constitutes valid knowledge; this knowledge is based, however, on the rather rigorous criteria of verification, replication, lack-of-falsification, logical and mathematical coherence etc. This scientific knowledge, although not "the objective truth", is as close to a description of the natural phenomena as one can get. The examples of such knowledge would be laws of thermodynamics, force-flux relations, quantum mechanics and its myriad experimental verifications. It is difficult to see how "People with different cultures, different gender, different world views may well understand the data differently . . "'8| say in quantum mechanics and still claim a degree of intellectual validity in their interpretation. Thus for all practical purposes, the laws of physics are "objective truths" although their validity may be limited to a given context, e.g., q u a n t u m mechanics must be applied to sub-atomic particles and is not needed in our day-to-day world where classical Newtonian mechanics (which, it can be shown, is a limiting case of quantum mechanics) would do. The concept of "constructed knowledge" becomes vital, however, when science attacks problems with under-currents (however hidden and subtle) of sexism, racism and ethnic bias etc. In such cases, the ideology and hidden agenda of the dominant group can be promoted under the pretext of "objective seeking of scientific truth" etc. This usually arises in the applied areas of science where the goal is not to discover new laws or phenomena but to harness them towards a societal goal. Take the case of mathematics. In pure mathematics, e.g., in the recent attack on Fermat's last theorem, it is difficult to see a gender or race bias etc. In applied mathematics, however, society must make a choice, for example, between devoting research f u n d s to the development of new missile systems or to some deeper analysis of the epidemiology of breast cancer. Here the developments LA PHYSIQUE AU CANADA juillet à août, 1 9 9 8 187 OPINION (ANTI-SCIENCE ATTITUDES...) in applied mathematics can mask a h i d d e n agenda under the guise of "objective" scientific knowledge. Constructivist epistemology finds its most extreme expression in the w o r k of the philosopher Feyerabend' 9 '. H e maintains that the rules of the so-called "scientific method", namely, (i) a new theory should be consistent with its predecessors; (ii) it should be consistent with available evidence; (iii) it should avoid ad hoc hypotheses; (iv) it should not be self-contradictory, have all been broken in those historical episodes which philosophers themselves regard as models of science at its best: Copernican revolution, kinetic theory, and q u a n t u m mechanics. H e further makes the point that data are never independent of theory and that the competing theories m a y be logically incommensurable. H e then argues that a scientific theory cannot be evaluated by testing it against experiment but only by confronting it with radical alternatives. This leads to the case for scientific pluralism, thus opening the door for confronting scientific theories with all sorts of world views, however "non-scientific" and bizarre. H e does not imply that the conventional science ought to win out in the end in this confrontation of world views. To quote Feyerabend: "The only principle that does not inhibit progress is: anything goes". In other w o r d s voodoo is as logical as mathematics; perpetual motion machines are as m u c h of a valid "socially-constructed knowledge" as laws of thermodynamics. One realizes that most scholars w h o support this position do not w a n t to take the valuable notion of constructed knowledge to the philosophical extremes advocated by Feyerabend' 91 . From the foregoing c o m m e n t s it is clear that the posture that "scientific positivism" has the key to truth cannot be sustained. It is also true that the notion of "constructed knowledge" w h e n applied to science and taken to its logical extreme can lead to absurdities and intellectual anarchy in which "anything goes". CONCLUSION Although it is stylish a m o n g social scientists to deny that science has any particular merit as a w a y of gaining knowledge about the world, it would still appear to be the best device for getting at reality (or rather some approximation of it) but without 188 PHYSICS IN CANADA July/August 1 9 9 8 pretending to be the key to gaining "objec tive truth". The notion of "constructed knowledge", on the other hand, is useful in elucidating the complex matrix of social interactions which determine our perceptions of the universe around us and thus our own conceptions of reality: one must guard against taking this notion, however, to extremes in which, for example, the laws of thermodynamics are defined in terms of your gender, race and ethnicity etc. Constructivist epistemology is undoubtedly a valuable tool in the social sciences or in the investigation of the interaction between natural science and society. Also, the learning of natural science, i.e., the assimilation of scientific knowledge, can be influenced by one's world-view. The laws of natural science, however, represent "objective" knowledge whose validity cannot be influenced by one's world-view. In this context, Richard Dawkins' 10 ' has been quoted as insisting that "there are no social constructivists at 30 000 feet w h o aren't hypocrites" the laws of aerodynamics are not subject to constructivist epistemology! In other words, one has the clear evidence of the objective validity of scientific knowledge every time one gets into an aeroplane or an elevator or when one switches on the lights or television or computer etc. It is absurd to think that the laws of electromagnetism change with one's world-view or culture or gender or ethnicity: electrons behave exactly the same u n d e r all cultures and this is an example of objective scientific knowledge' 11 '. REFERENCES A N D N O T E S 1. A.J. Bard, Chemical and Engineering News, 1996, 74 (#17), 5. 2. B.E. Babich, C.B. Bergoffen and S.V. Glynn (Eds), Continental and Postmodern Perspectives in the Philosophy of Science, 1995, Aldershot and Brookfield, Vermont, Avebury. 3. A. Belsey, Brit. I. Phil. Sci.. 1997,48, 281. 4. A.K. Vijh, Sci. & Engg. Ethics, 1996, 2 (#1), 5. 5. A.K. Vijh, Physics in Canada, 1993,49 (#1), 25. 6. H. Hillman, Sci. & Engg. Ethics, 1995,1,49. 7. P.A.M. Dirac, Sci. Amer., 1963, 208 (May), 45. 8. P.J. Gilmer, Sci. & Engg. Ethics, 1995,1,71. 9. P.J. Feyerabend, Killing Time: The Autobiography of Paul Feyerabend, 1995, University of Chicago Press, Chicago. 10. R. Dawkins as quoted by H.M. Collins, Nature, 1995, 376,131. 11. This text is also being simultaneously published in Canadian Chemical News, 50(#6), 21 (June 1998). ARTICLE D E F O N D ( S T O N E H E N G E I) STONEHENGE I by K.G. McNeill S tonehenge I - consisting of a Bank, Ditch and 56 "Aubrey Holes" - has been thought of as an eclipse-predicting computer. In this model, simple questions arise - w h a t defined the centre of Stonehenge I, w h y are there 56 Aubrey Holes, w h y are these holes the size they are. Suggestions are made to answer these questions. INTRODUCTION "the centre", nor how it should be or was defined. The architects of Stonehenge I could not have used the centre of the Sarsen Circle nor of the ditch or of the Aubrey Holes themselves. The builders must have decided on a centre and worked from that. How did they define it? A point on a surface may be defined by the intersection of two lines. There would be little argument that one relevant It has been suggested that the earliest line is that defined by the structure at Stonehenge - Stonehenge I, midsummer sunrise (first consisting of a Bank, Ditch and 56 "Aubrey light) (bearing 49.3°) and hole 97, or off-centre from the Holes" - was used as a computer for Heelstone as shown by the predicting the occurrence of eclipses ... "axis" in Figure 1. The origins and purposes of Stonehenge have long excited interest. It has been suggested that the earliest constructions there - the Bank and Ditch, and in particular the 56 Holes which were d u g just inside the circular Bank - were used as a computer for predicting the occurrence of eclipses.(1,2' These early (3000 BC) structures are generally known as Stonehenge I and are indicated in Figure 1. The 56 Holes are usually called the Aubrey Holes after their seventeenth century describer, John Aubrey. Despite the great interest, including suggestions as to how such a computer worked, there are a number of simple questions to which no completely satisfactory answers have been given. For instance, how was the centre of the circular bank ( a n d / o r of the Aubrey Hole circle) determined? Why are the Holes so big - 1 or 2 metres diameter and about 1 m in depth - when digging them with deer antlers or shoulder blades was a labourious task? Why were they back filled? Why are there 56, not 57 or 67 Aubrey Holes? North' 31 has given an answer to this last question, but in terms of geometry. Possible answers related to the computer model are discussed here. THE CENTRE OF S T O N E H E N G E Many astronomical directions at Stonehenge are measured with respect to North from "the centre" of the structures. However it is not clear which point is I suggest that the other line was based on the direction of the summer solstice sunset. This at Stonehenge will be 99° anti-clockwise from the direction of sun rise; but to define the particular line requires a point through which the line passes. The surface of the Stonehenge area 4 is not quite flat, but has variations on top of a general east-to-west slope of about 1.5 metres over the 100 m or so of the general area. In particular there is a "cup" of about two feet depth near what is now termed stone 93. I further suggest that the "centre" was defined to be the line defined by the summer solstice setting sun and this "cup", so that "the centre" is the place where, standing on the sunrise - 97 line, the sun appeared to set into the "cup". This point of intersection of the sunrise line and the sunset line is in fact O a , now termed the centre of the Aubrey holes circle: but on this suggestion the centre was the basis of the Aubrey circle, rather than the circle defining the centre. Dr. Kenneth McNeill is a Professor in the Physics D e p a r t m e n t at the University of Toronto LA PHYSIQUE AU CANADA juillet à août, 1998 189 FEATURE ARTICLE (STONEHENGE) Heel Stone Suggested line Slaughter Stone (prone) OUTER BANK Station Stone 91 I I I 10 Fig. 1 20m A schematic d r a w i n g of Stonehenge I (-3000 BC) s h o w i n g (a) the Ditch (with gap to the s u m m e r solstice sunrise direction) (b) the inner Bank set on an approximate circle 86.6 m in diameter, (c) a lower "counter scarp" or outer b a n k (d) the positions of the 56 A u b r e y Holes just inside the inner Bank (e) the "axis", based on the direction of s u m m e r solstice sunrise as seen over hole 97 and on the line of the " A v e n u e " (f) the suggested line based on the observing of the s u m m e r solstice s u n setting into the " c u p " near to station stone 93; the intersection of (e) and (f) could h a v e defined the center of Stonehenge; this point is indeed the centre of the circle of Aubrey Holes. Also s h o w n , in solid black, are the positions of currently standing stones, probably all of which were set-up much after Stonehenge I, b u t w h i c h n o w are the most obvious features of Stonehenge. The edge of the present-day road is indicated. The latitude of Stonehenge is 51° 11'. W H Y T H E R E A R E 56 A U B R E Y H O L E S A T STONEHENGE? R e l a t i v e m o t i o n s of t h e e a r t h , m o o n a n d s u n c a n b e r o u g h l y s i m u l a t e d b y a m o d e l in w h i c h the s u n a n d m o o n m o v e in orbits a r o u n d the earth, orbits w h i c h 190 L. PHYSICS IN CANADA July/August 1998 a r e tilted a t 5° t o o n e a n o t h e r . T h e p o i n t s of i n t e r s e c t i o n of t h e o r b i t s , t h e n o d e s , t h e m s e l v e s circle w i t h a p e r i o d of 18.61 y e a r s . A l u n a r e c l i p s e t a k e s p l a c e w h e n t h e s u n , e a r t h a n d m o o n a r e m o r e or less c o l l i n e a r — ±12° of e x a c t l i n e a r i t y g i v e s t h e L u n a r ARTICLE D E F O N D Ecliptic Limit. For this to be true there must be a full moon at the time at which both the sun and the moon are respectively at the two intersections of their respective orbits. For a solar eclipse, the sun and the moon must be at the same node. Again there is a possible variation: the solar ecliptic limit is ±18°. 121 As others have suggested' the changes in the relative positions of the sun, moon and nodes can be represented on a plane by markers moving at different rates round a circle - the moon marker progressing so that it completes the circle in one month, the sun marker in one year. Clearly, as the sun and the moon move continuously, a proper representation would require continuous motion of the markers; as with most clocks, in a practical representation movement must take place discontinuously, at second intervals or at some other fixed rate. We then can think of the circle having a number of holes or positions on it, with markers being moved from one to the next at the appropriate time interval. The larger the number of holes the better the spatial (angular) definition and the temporal resolution; that is, if w e had only ten holes round the circle, a lunar marker at 0° to some reference direction at position 1 would only tell us that the moon was somewhere between 0° and 36° (as position 2 would be at 36°). Such a large uncertainty in position is not acceptable as the lunar ecliptic limit is 24°; and to predict lunar total eclipses the allowed uncertainty is about a half of this (12° or so). 12° between adjacent positions implies 30 positions round the circle, a number which is temptingly near 28, the number of days in a month rounded u p to the nearest whole number. Taking for the sake of discussion a circle with 28 positions round it w e can consider how such a system could be used to predict the relative motions of the sun, moon and nodes. Let us start on the day of a total lunar eclipse, with the sun and a node in position 1 and the moon (and the other node) opposite on the circle in position 15. For the moon marker to represent the monthly cycling of the moon it has to be moved once a day. It will then be back at position 15 after 28 days. The moon however cycles in 27.3 days, so an error of 0.68 days, or 2.4%, is present. ( S T O N E H E N G E I) The sun marker has to take 1 year to cycle, so it can only be moved once every 365.25/28 days, or 13.04 days. Approximating this by 13 days introduces a further error of 0.3%. The node marker(s) should take 18.61 years to cycle,and so gets moved every 243 days. An interesting event is predicted 14 or 15 days after the lunar eclipse which occurred at the above initiation of the programme of the markers. At 14 days the moon marker will be in position 1, as will be the node marker, and the sun marker will be in position 2 (on day 15, node marker is in 1, and both the moon and the sun markers are in 2). As the angle between 1 and 2 is 12° and the solar ecliptic limit is ±18°, the close proximity of the markers predicts a sufficiently close collinearity of the actual earth, moon and sun to produce a solar eclipse. However, the small number of positions and the corresponding poor time resolution is a disadvantage. All the conjunction tells is that sometime around day 14 or 15 a solar eclipse will somewhere be visible; common sense says that approximately half the time, during the night, this eclipse cannot be visible. It would be helpful if instead of one position per day there were two, a night position and a daylight position, the change of markers taking place at 6 am and 6 p.m. or thereabouts. Then one could better predict if an eclipse were to be visible. This suggests 56 positions; but would not 55 be better, as it is the closer whole number to 27.32 days x 2 = 54.64 days? Indeed, any number of positions is usable with a sufficiently complicated programme of movement. We will consider not only 55 and 56, but indeed nine possible numbers of positions around 56. Above 60 the angular separation between adjacent positions, <6°, is unnecessarily fine, bearing in mind the ecliptic limits, and the effort required to make additional positions would be wasteful. With 55 positions, the moon marker would be moved twice a day (at 6 am and 6 p.m.). After 27.5 days it would have completed the circle, while the moon would actually complete its course in 27.32 days, a difference (error) of 0.67%. For the sun marker, if started in position 1 and if it were moved two positions every 13 days, it would be in position 55 after 351 days and in position 2 (having skipped position 1) after 364 days. Clearly it would be better to move by LA PH YSIQUE AU CANADA juillet à août, 1998 191 FEATURE ARTICLE (STONEHENGE) one position after 7 days and then after another 6 days; with this new regimen again position 55 would be reached in 351 days and position 1 in 358 days. As the sun would not regain its initial position until after 365.25 days, there is a 7.25 day, or 2.0% error; the next year, starting with a 6 day move, would produce a 2.2% error, so an average w e may take a solar marker error of 2.1%. For the nodal marker, the node marker would be moved (in fact in the opposite direction to the sun and moon markers) once every 18.61 x 365.25/ 55 days = 123.587 days. Approximating this by 124 days gives an error of 0.3%. The total (linear sum of moduli) error is then 0.7% + 2.1% + 0.3% = 3.1%. For 54 positions moon markers would be moved twice a day, sun markers after 7 and 6 days, and the node markers after 126 (125.89) days. The corresponding moon, sun and nodes errors for 54 positions are 1.2% + 3.9% + 0.1% = 5.2%. For 56 positions, the corresponding errors are 2.5% + 0.3% + 0.3% = 3.1% and for these and other configurations No. of Positions % Error 52 5.3 53 4.8 54 5.2 55 3.1 56 3.1 57 5.9 58 9.5 59 11.2 60 11.5 where, in all cases, the best simple regimen has been applied, that is, the simple regimen which gives the smallest error; this means in every case changing the rule for moving the node marker; for 52 and 53 positions moving the sun marker every 7 days, for 59 and 60 positions every 6 days and for the rest 7 then 6 days; the moon marker in all cases is moved twice a day. 192 PHYSICS IN CANADA July/August 1 9 9 8 It will be seen that 55 and 56 positions give equally the lowest error. An arrangement with 56 positions has however certain advantages over one with 55; 56 is not only even, but it has 4 and 8 as factors, while 55 is odd and has but two factors, 5 and 11. This ability to break the year (or month) into quarters and eighths, as we do into quarters and twelfths, may well tip the balance towards the use of 56 positions. 56 could then be the "good number" to use in making a predictor of solar and lunar phenomena. It is clearly of interest that at Stonehenge there are 56 Aubrey Holes. As noted earlier, North' 3 ' also, but from a different viewpoint, concluded that 56 was a "good" number of Holes. He assumed that each held a massive post, of diameter 30 or 40 cm, and that these could be used to define angles. He considered three angles of interest - for example the difference, 81°, between the directions of setting of the sun in winter and summer. The actual angle subtended at the centre by 14 of 56 posts is 83.5° , but by taking into account the thickness of the posts ("Taking the line to graze the adjacent post") he considers he gets reasonable agreement and that 56 posts give a better agreement than do either 55 or 57. The o ther tv/o angles considered again do not give complete agreements, but support his conclusion. Further study should be made of these hypotheses. THE STONEHENGE AUBREY HOLES The Aubrey Holes have been suggested to have been a computer for predicting eclipses'1-2'. Some corroborative evidence for this comes from the fact that, as discussed earlier, 56 is a "good" number for such a device, and that there are 56 Aubrey holes. Hoyle' 2 ' suggested that stones might have been used as markers in the Aubrey holes, moving a moon marker twice a day and a sun stone every 6 or 7 days. However the holes were so big (perhaps' 5 ' 2 meters across, 1 meter deep), that the stones would presumably have been correspondingly large and heavy (more than 10 kg) and heaving them from the bottom of a pit twice a day would be a poorly designed task. Robert Wilkinson' 6 ' has suggested that the pits were d u g one year into the chalky clay then overwintered to break it d o w n somewhat before the holes were ARTICLE D E F O N D back-filled with the now more friable soil. This soil would be receptive of w o o d e n stakes acting as markers, and make the task of moving markers much simpler. This idea makes reasonable the deduction' 7 ' that the holes were back-filled within a year or so of digging. The size of the holes will be discussed later. On the Wilkinson model the sun stake must be moved every 6 or 7 days, which implies two more staves, one to show whether the previous move took place after 7 or 6 days, and another to count off the 6 or 7. As an error of 0.3% is introduced (as discussed above) by approximating 365.25 days by 6.5 x 56 (=364.00), a correction has to be m a d e of 1 hole every 300 holes, that is 1 hole every 5 years; some record has to be kept when this corrections to be made, perhaps by 2 stakes, one fixed and one moved every year. Thus instead of just a single sun marker there have to be perhaps halfa-dozen. Similarly with the moon markers. Clearly one starts with one main stake moved twice a day. The "error" caused by approximating 27.32 by 52.2 is 2.5% or 1.4 holes in 56; so every two months the moon marker has to be corrected by 3 positions, or, better, one each month and an extra one every two months (this overcompensation will leave an error of 0.1 holes in 56, or 1 hole in 10 months - so every year one might start the year off by giving a zero move rather than a one-hole one). To denote whether a month is in an " o d d " month rather than an "even" one requires at least one marker. It may be helpful to have a marker to indicate whether the moon marker was last moved at sunrise or at sunset, giving three or so moon stakes required. For the two nodes, two main markers are required, and then also markers to count 121 days. This would need one circulating marker, moved each day, plus two others to show that 56, then 112 days, had elapsed. Movement of the 2 main markers could follow 2 revolutions (112 positions, 2 markers to indicate this) and nine further movements of the circulating marker. The 0.3% error introduced by approximation means a 0.003 x 56 = 0.176 position error per 18.61 cycles or 1 position every 5.7 cycles or 1 position per century. Can one say that it is unlikely that a marker would be dedicated to count a century? ( S T O N E H E N G E I) In total then, and even without the "back-up" markers which any computer work needs, u p to 15 markers are required, with the possibility of many being, at one time or another, in the same position. It is not unreasonable to allocate a tenth of a square metre (or a square foot in those days) for each marker - perhaps in total 1 metre square of deep friable earth would be ample. A circle of area 1 metre square has a diameter of just over a meter; the 1 or 2 meter diameter of the actual Aubrey holes is not unreasonable when one realizes that the stakes require a depth of soil which might not be available at the edges of back-filled hole. These considerations of hole size are then consistent with the Wilkinson hypothesis of back-filled holes with stake markers. Of course such stakes would be at more risk of being moved by sheep than would Hoyle's stones; consistent with this, the Bank and Ditch seem to be arranged to keep animals out rather than acting to keep them in. The discussion above on the size of the Aubrey Holes is based on the "computer model" - for North's geometric model the arguments run differently. The computer model requires that the Holes are consistent in size and number with the need to plant a dozen or so staves in 56 positions. North argues from the size of the holes that in each a large post has been planted, and that from the sizes of these posts further conclusions could be drawn. Again further study should be made. REFERENCES 1. G.S. H a w k i n s , "Stonehenge Decoded", Dell Publishing Co., NY 1965. 2. F. Hoyle, "From Stonehenge to Modern Cosmology", W H Freeman & Co., San Francisco 1972. 3. John North, "Stonehenge", The Free Press, N e w York, 1996. 4. G. S. H a w k i n s , "Beyond Stonehenge", H a r p e r a n d Row N e w York 1973. 5. R.J.C. Atkinson, S. Piggott and J.F.S. Stone, " The Antiquaries Journal XXXII", 1, 214-20,1950. 6. R.H. Wilkinson, private communication, 1987. Robert Wilkinson w a s a m e m b e r of the School of Physics at the University of Melbourne, lecturing in Astronomy. At the time of his death in 1988 he w a s working on the draft of a m o n o g r a p h on Stonehenge, but this did not reach the stage of publication. 7. Letter f r o m R.J.C. Atkinson to R.H. Wilkinson quoted in above draft m o n o g r a p h (ref. 6). LA PHYSIQUE AU CANADA juillet à août, 1998 193 FEATURE A R T I C L E ( A R C H A E O L O G I C A L PROBLEMS. ..) ARCHAEOLOGICAL PROBLEMS: SCIENTIFIC SOLUTIONS by D.C. Baird own experience (mostly at the Laboratory for Archaeological Science and the History of Art in s soon as systematic excavation replaced Oxford, England) and use examples that come mostly treasure hunting in archaeological from European and Middle Eastern archaeology. Let exploration, scientific laboratory methods us start with one of the oldest of archaeological came into use to supplement a n d / o r replace the conundrums, the identification of sources of cultural stylistic judgements that had formed the basis of most influence. earlier analysis of archaeological material such as This article is based on lectures given THE MEGALITHIC pottery, tools, sculpture, etc. during CAP Lecture tours in Ontario and M O N U M E N T S OF As early as the 1880's the WESTERN EUROPE, Or Konigliche Museum in Berlin British Columbia in 1994 and 1995. To Where did the ideas come was operating a permanently illustrate the contributions of science to f r o m to build Stonehenge? staffed laboratory to study archaeology, the lecture concentrated on artefacts. The Museum did a few particular examples in which not survive World War I, but For hundreds of years people scientific methods have had a significant from 1920 onwards the British have marvelled at the impact on archaeological thinking. Museum in London, England, well-known megalithic: employed Dr. Scott, a monuments of the British Isles and Western Europe. The famous Stonehenge in chemist, to initiate the chemical analysis of material in Southern England is only one of many hundreds of its collection. Since then, archaeological science has megalithic monuments, stone circles, stone alignments developed to the point that hardly any procedure or and burial tombs. Fig. 1 shows the familiar technique exists in scientific laboratories that has not Stonehenge, and also Maeshowe, a Neolithic burial been applied to archaeological material. The impact cairn remotely located in the Orkney Islands off the has been little short of revolutionary. North coast of Scotland. In a short article there is no hope of providing even a These wonderful structures, with their sophisticated sketchy outline of the whole range of scientific techstone construction and clear indications of the niques used in archaeology. Instead, I have chosen a builders' astronomical expertise, have long raised one few significant examples to illustrate ways in which simple and obvious question. How could the scientific methods have brought about major changes supposedly primitive agricultural peasants of the in thinking or understanding in a particular field of region have constructed such sophisticated archaeology. For a more complete description of the structures? whole range of archaeological science the reader is 6 81 5) referred to the many excellent texts in the area' " . In order to avoid belabouring familiar physics, I shall mention the physical principles and their associated instrumental methods only briefly, and concentrate Dr. Baird is a Professor Emeritus with the instead on the nature of the archaeological problems D e p a r t m e n t of Physics, Royal Military College,. Kingston, Ontario K7K 7B4. Tel: 613 548 4338, and the archaeological significance of the results. Fax: 613 548 4338, e-mail: [email protected]. Much as I would like to include examples drawn from American archaeology, I have chosen to draw on my A 194 PHYSICS IN CANADA J u l y / A u g u s t 1998 ARTICLE D E F O N D To most observers in the past the answer was obvious. The expertise must have come from other, more highly developed centres of technology and civilization, and there was one obvious choice for a such a source. The established civilizations of Mesopotamia and Egypt had m a d e an early start both in astronomical knowledge and in sophisticated architecture, and had left m a n y examples of early stone structures. Outstanding amongst these is the Pyramid of Djoser (Fig. 2), dated by historical records to about 2700 BC. It is our earliest example of major stone architecture, a landmark of architectural genius in itself. Fig. 1. Examples of megalithic ( A R C H A E O L O G I C A L PROBLEMS...) across the Mediterranean towards the Iberian Peninsula, which acts as a gateway to NW Europe and the offshore islands. All European dates for megalithic architecture, therefore, were held to post-date the Egyptian originals by a time interval sufficiently long to allow for the spread of the expertise. So convincingly obvious was this idea (first articulated by Sir John Evans in the 1870's) that it formed virtually the sole basis for the development, largely by the celebrated Vere Gordon Childe, of archaeological chronologies in Western Europe for the next 75 years. Stonehenge (left) a n d M a e s h o w e (right). Egypt, it was thought therefore, must have provided the expertise underlying the megalithic monuments of Western Europe. To add plausibility to such a belief, megalithic m o n u m e n t s can be found in a path leading At that point Dr. Wilfred Libby'61 appeared on the scene in Chicago. It is unnecessary to repeat in detail the familiar story of the development of radiocarbon dating or to describe the current methods. Ample reference material will be found in the Bibliography. Suffice it to say that the decay of C14, formed by cosmic ray bombardment in the upper atmosphere and decaying subsequently with a half life of -5730 years, can provide a measure of the time interval since the removal of a living organism from the life cycle within which it had contained the equilibrium value for the C14:C12 ratio. This gross oversimplification of the description masks the immensely sophisticated techniques that must be observed all the way from initial excavation of the material through handling and specimen preparation to the actual counting of the feeble radioactivity that remains in the sample, particularly in small or ancient specimens. Even the most scrupulous attention to such detail, however, cannot protect us from error that arises from LA PHYSIQUE AU CANADA juillet à août, 1998 195 FEATURE ARTICLE ( A R C H A E O L O G I C A L PROBLEMS. ..) possible variation in the original rate at which the C14 was produced during the time when the specimen was still alive. Since this is unknown, w e are dependent on calibration using material of known date. Libby's original work used material from Egypt that was of established historical age, but the most important calibration has later been supplied by the Bristlecone Pine trees (Fig. 3) that live high in the arid, cool air of the Sierra Nevada of California' 71 . the dates in general not post-date the supposed Egyptian originals, they emerged consistently hundreds of years earlier. The supposedly barbaric agricultural peasants could not possibly have learned from their Middle Eastern betters, and must have found out for themselves how to build these marvellous structures. Profound dismay in the British archaeological community resulted from this overturning of the traditional chronology One of the leading prehistorians of the day, Stuart Piggott, Professor of Prehistoric Archaeology at the University of Edinburgh and author of the encyclopaedic Neolithic Cultures of the British Isles d e c l a r e d t h e n e w dates for one site as "archaeologically unacceptable". conventional radiocarbon dales in radiocarbon yean before posent Because of the deprived nature of their environment, these trees grow very slowly and live for thousands of years, placing them amongst the oldest living organisms. Analysis of their growth rings and sampling of the interior wood, therefore, provides accurately dated organic material that can date back over 7000 years. The resulting calibration curves constructed by Suess (Fig. 4) have enabled radiocarbon dating to provide (within the limits of the ambiguity introduced by the kinks in the curve - at the most one or two h u n d r e d years) accurate dating over a large part of the age scale that is important in archaeology 181 . The resulting radiocarbon dates for the megalithic structures in Western Europe hit the archaeological scene in the 1950's like a bombshell 19 '. Not only did 196 PHYSICS IN CANADA J u l y / A u g u s t 1998 bmtlecone pine d a t a in calendar yean Fig. 4 The Suess radiocarbon calibration curve for recent (upper) and ancient (lower) dates (age increasing f r o m right to left). The gap between the horizontal line and the calibration curve s h o w s the progressive difference between calendar dates a n d radiocarbon dates as age increases. So, what is the point? Does it really matter that the Neolithic farmers in the UK and Western Europe turned out to be smarter than they had been given credit for? It actually did matter a great deal, because what was at issue was the whole pattern of thinking in European archaeology. Stuart Piggott s phrase ARTICLE D E F O N D reveals that he, like all the other archaeologists of the time, were not clearly aware of the distinction between their ideas about the past and the actual events. To us in present-day science, the obvious distinction between, on the one hand, our humanly-produced models of systems and, on the other hand, our observations on the actual behaviour of the systems is familiar and natural, but it was a revelation to the European archaeologists of the 1950's. To his credit, it did not take long for Stuart Piggott to realize that he was dealing with a revolution, and a whole new generation of archaeologists has been liberated by the awareness of the role played by models. As a consequence, radically new concepts are n o w being proposed for many of the old, familiar problems. ( A R C H A E O L O G I C A L PROBLEMS...) thinking is clear - w e are discussing provisional models, not archaeological "certainty". Incidentally, one would think that it would be very difficult to obtain archaeological evidence relating to the ethnic continuity postulated by Renfrew. The recent discovery, however, that "Cheddar Man", a skeleton derived from Palaeolithic deposits in a cave in Cheddar Gorge in SW England, is closely connected by DNA evidence to a present-day resident of the area provides intriguing encouragement for speculation. RADIOCARBON D A T I N G W I T H SMALL SAMPLES For example, consider the old problem of the spread of the Indo-European languages. Although a common origin for most of the European languages had long been supposed, it was a surprising novelty when a British judge in the late 18th century in India noticed that the ancient liturgical language of the region, Sanskrit, is very similar to Latin and Greek. If one supposes a common linguistic ancestor, therefore, it was natural to imagine a common starting point from which the Indo-European "people" spread out to conquer and displace earlier people, thus spreading the Indo-European family of languages over a vast area from the Western Isles of Scotland to the plains of Northern India. The only trouble with that idea was that, although the linguistic analysis of the various languages was sound and consistent, it was never possible to find an identifiable archaeological "signature' (architecture, pottery, weapons, burial practices, or whatever) for this supposed people. Liberated by new awareness of the actual dates for the megalithic structures, Colin Renfrew 110 ' has proposed a model for the spread of the Indo-European languages that does not rely on the traditional "invade-conquer-and- displace" model of cultural change. Rather, he imagines the language group to have spread amongst the existing people in a region borne on, as a carrier, the new technology of agriculture. A process such as this could result in a peaceful spread of the language without obvious archaeological markers on the cultures. Renfrew's model may not stand the test of time without modification, but it is an original and innovative departure from earlier ideas, and at least now the Radiocarbon dating of the traditional variety has, as we have indicated, been responsible for remarkable progress in archaeology, but it has one significant defect - the concentration of C14 in living matter is not high to begin with. Only a few kilograms of C14 are produced each year over the whole earth, and as a result the equilibrium concentration in living material is only of the order of 10"12. This low initial concentration, when coupled with the low decay rate of C14, results in such low counting rates, especially in small or old specimens, that long periods of counting may be required to provide adequate precision. It would clearly be more effective if we could measure the C14:C12 ratio directly using, for example, a mass spectrometer. The problem in such direct measurements arises from the obvious possibility of confusion between C14 and the enormously more abundant N14. The answer to the difficulty was based on work done at Chalk River. There, experiments using the tandem Van de Graaff accelerator had shown that nitrogen does not form stable negative ions. As a consequence, discrimination between C14 and N 14 becomes possible if one uses negative instead of positive ions in the acceleration stage of the mass spectrometer. The feasibility of the method was demonstrated simultaneously by one group at McMaster University' 11 ' and one from Rochester and Toronto' 12 '. The first accelerator dedicated to radiocarbon dating was constructed at Oxford University (see diagram in Fig. 5), and has been supplying dates on a routine basis for over 15 years'" 1 . Several other accelerators are now also in use around the world. LA PHYSIQUE AU CANADA juillet à août, 1998 197 FEATURE ARTICLE ( A R C H A E O L O G I C A L PROBLEMS. ..) DETECT OU SLITS W1EH FILTER SLITS ANALYSER MAGNET SLITS »l ripper foil al 1 5 MV ^ C 3 * Fig. 5. D i a g r a m of the radiocarbon dating accelerator in Oxford. Apart from their obvious application to very ancient specimens, the major contribution of the accelerators has come from their ability to make accurate measurements on very small specimens. To illustrate, I shall mention only two examples in which only tiny amounts of material were available. The famous Shroud of Turin first came to light in France in the 1350's in the form of a linen cloth bearing marks that were claimed to represent the crucified Christ (Fig. 6). As a consequence, it was venerated as the actual burial shroud used after the Crucifixion. The Shroud found its way to the Cathedral In Turin where it is preserved and periodically exhibited. In 198 PHYSICS IN CANADA July/August 1998 view of the widespread interest in its authenticity, the Shroud attracted the attention of scientific investigators from time to time, using such techniques as various forms of photography, but the results were inconclusive. The obvious possibility, radiocarbon dating, was never attempted on account of the unacceptably large amount of material that was required using the traditional techniques The Shroud, therefore, was an obvious candidate for accelerator-based radiocarbon dating, and in 1988 samples of the Shroud, along with control samples of material of varying date, were submitted to laboratories in Tucson, Arizona, Oxford and Zlirich. The result was conclusive. The three laboratories agreed in placing the Shroud with 95% confidence in the date range 1260-1390 AD[14]. Even this clear-cut answer, however, has not been sufficient to satisfy those for w h o m authenticity of the Shroud is important, and who are still writing books to suggest that, for one reason or another, all three laboratories are mistaken and the Shroud is genuine. A second case has more recently appeared in which a highly significant dating problem was associated with severe limits on the amount of available material. In September, 1991, two hikers in the Tyrolean Alps discovered a h u m a n body high in the permanent ice of a glacier' 15-16,17). Discoveries of bodies in glaciers are not uncommon, and little interest was evoked until it gradually became clear that this one belonged to no unfortunate tourist who had recently ARTICLE D E F O N D fallen into a crevasse in the glacier. By the time the significance of the find had been recognized, much damage had been done by clumsy attempts at recovery of the body. Even so, this has been a find of absolutely unique significance. The virtually complete body seemed to belong to the Early Bronze Age, and had been perfectly preserved by the ice (see Fig. 7). No other intact body of the period exists in Europe, but, in addition, he had with him his complete stock ( A R C H A E O L O G I C A L PROBLEMS...) of tools and equipment. They included a bow and arrows, flint knife complete with wooden handle, an axe, still bound into its wooden handle, a purse, and a full set of clothing. Some of these artefacts are illustrated in Fig. 8. Nothing remotely like this had ever been found before. On the basis of the typology of the axe, the archaeologist in charge of the find confidently placed the date of the Iceman at about 2000 BC. This would have been exciting enough, since, as we have mentioned, nothing remotely comparable from the Early Bronze Age exists, but the obvious desire for more accurate dating, coupled with the impossibilty of using anything other than tiny specimens, made the use of accelerator-based radiocarbon dating mandatory. The date, from the Oxford lab, turned out to be not 2000 BC, but around 3200 BC|18]. The Iceman is not Early Bronze Age, as had been supposed; he is Chalcolithic, i.e., from the age of copper, which predates the Bronze Age. This is confirmed by elemental analysis of the axe, which turns out to be pure copper and not bronze. Not only is our Iceman an incredible and unique relic of the past, but he comes right at the beginning of metal-using culture in Europe. He will be the source of stimulating speculation for many years to come. LA PHYSIQUE AU CANADA juillet à août, 1998 199 FEATURE ARTICLE ( A R C H A E O L O G I C A L P R O B L E M S . ..) DATING W I T H O U T C14 Let us now turn our attention to other methods of dating. Radiocarbon dating is limited, generally, to organic, i.e. once-living, material, but much significant archaeological material is non-organic. Consider for a moment crystalline, insulating material. This might appear in, for example, pottery, in which the original clay can contain crystals such as quartz, feldspar, zircon, etc. It turns out, too, that material in living organisms can be crystalline; the dentine of tooth enamel, for example, contains the mineral hydroxyapatite. Whatever the origin, then, of such insulating crystals, consider their fate in an archaeological environment. N o such crystal can be free from radioactive contamination. Uranium, thorium and other long-lived radioactive species are present everywhere as low-level impurities, whether in the crystals themselves or in the surrounding soil, and the resulting radioactivity produces radiation damage in the crystal. As illustrated in Fig. 9, electrons from the valence band of the insulating crystal can be excited to the conduction band, from which, after a brief period of mobile freedom, they can make a transition downwards. ,•'/ ' [anductmn ban .////. If the electrons fall back to fill a hole in the valence band, a photon will be emitted and the process is complete. In a certain fraction of cases, however, electrons can fall into trapping centres, in which, depending on the energy intervals involved and the ambient temperature, the lifetime of occupation can be very long. If one starts, then, with a crystal in which there is zero occupation of trapping centres, the number of trapped electrons at a subsequent time will provicie a measure of the length of time during which radiation damage was accumulating. An actual measurement of the time since the trapping centres were empty requires us to know two things, the sensitivity of the crystal to radiation damage and the dose rate to which the crystal was subjected. Both of these can be measured, or accurately enough estimated. The particular technology of the dating process depends on the method by which one interrogates the trapping centres to find out the number of trapped electrons. There are a number of possible methods, of which we shall describe only two that are particularly significant for archaeological purposes. A third method of detecting the trapped electrons was developed by David Huntley and co-workers at Simon Fraser University 119 '. It uses light to detect the trapped electrons, and consequently has been most significant in dating lake bottom sediments that have been preserved in darkness. / / / / A / / / / . trap-^- -lumtonnm ctntrt Fig. 9 200 light Excitation a n d de-excitation of electrons between the valence b a n d , the conduction b a n d a n d t r a p p i n g centres in an insulating crystal. PHYSICS IN CANADA July/August 1998 The first method to be used historically depends on the phenomenon of thermoluminescence. It had been known at least since the 17th century that certain insulating crystals have the property of emitting light when heated. Sir Robert Boyle reported in 1664 that a diamond that he had taken to bed with him (for unspecified purposes) glowed visibly when warm. As an archaeometric tool the phenomenon was developed largely by Stuart Fleming and Martin Aitken120'51 in Oxford during the 60's and 70's to the point that, given sufficient care and skilled attention, thermoluminescence dating is today a tool of the greatest importance. Its great advantage lies, of course, in the fact that it applies, amongst others, to ceramic materials that are abundant in the archaeological context and for which radiocarbon dating is inapplicable. ARTICLE D E F O N D In principle, the method is simple; one obtains a measure of the number of trapped electrons by heating the specimen and measuring the light thereby liberated. This will give a measure of the time during which radiation damage has accumulated since the last time at which the traps were emptied by heating. In the case of pottery, this is usually the date at which the pottery was fired. As mentioned earlier, the only other quantities for which one requires values are the dose rate to which the crystal was exposed and its sensitivity to radiation damage. The age will then be obtained from the equation AGE = Thermoluminescence Sensitivity x Dose Rate Of the three quantities in the equation, the numerator is relatively easy to measure. On a heatable platform (see Fig. 10) the prepared specimen is heated in a light-tight enclosure and, as a function of temperature, the light emitted is measured by an electron multiplier tube to produce a glow curve, also shown in Fig. 10 for specimens of varying ages. The sensitivity of the crystal to radiation damage can be measured by irradiating the sample material in the laboratory using a suitable, calibrated radioisotope source and measuring the resulting thermoluminescence. The dose rate to which the specimen was exposed ( A R C H A E O L O G I C A L PROBLEMS...) since firing may be more difficult to determine. The contributions may arise from radioactive impurities in the specimen material itself, or from radioactivity in the surrounding soil if the pottery had been buried. Fortunately, much of the radiation damage that is measured in thermoluminescence dating arises from short-range radiation ( a and P rays) from a variety of radioactive impurities (mostly U, Th and K40), and so, frequently, most of the accumulated damage results from internal impurities whose concentration can be measured in the laboratory. If a substantial part of the radiation damage has arisen from sources external to the specimen, more difficulty, and consequent uncertainty, will arise unless measurements of the dose rate can be made on-site at the time of excavation. In addition to these obvious requirements, further examination of the specimen must be made to study the range of trap depths involved in the thermoluminescent measurements. In addition, none of the above conveys an impression of the enormous amount of care that must be taken during the whole process from the primary collection of the specimen (for example, complete darkness may be required to prevent premature emptying of traps) and its preparation (it may be necessary to isolate individual minute crystals under a microscope) to the final measurements. Thermoluminescence dating requires such care that 300 - 200 H 100 100 200 300 Temperature (°C) 400 Fig. 10 The electrically heated platform for thermoluminescence m e a s u r e m e n t s (left) and the resulting glow curves for a variety of specimens (right). LA PHYSIQUE AU CANADA juillet à août, 1998 201 FEATURE A R T I C L E ( A R C H A E O L O G I C A L PROBLEMS. ..) only highly skilled and experienced workers can provide dates with accuracy and reliability. OTHER M E T H O D S OF DETECTING TRAPPED ELECTRONS: The Problem Of The Neanderthals Because of the types of material for which thermoluminescence dating is effective, the method is commonly used in authenticity testing. As just one example among the many that could be described, the Bronze Horse in the Metropolitan Museum of Art in New York (Fig 11), acquired in 1923, was long hailed as an unusually fine example of bronze sculpture from the time of classical Greece, but was accused in 1967 by a member of the Museum staff of being a modern forgery. We started our discussion of thermoluminescence dating by noting that radiation damage in crystals could provide a measure of the interval of time during which the radiation damage had been accumulating, irrespective of the method used to determine the magnitude of the accumulated radiation damage. Furthermore, if the sample has been preserved from heating or other perturbation that could accelerate the emptying of the electron traps, the radiation damage will increase steadily with time, and the agemeasuring process will become progressively more effective as the age of the sample increases (in contrast to radiocarbon dating in which the difficulties increase with age). To resolve the matter, the bronze material itself would be very difficult to date accurately, but, fortunately, the horse had been cast (using the "cire perdu" method) with its interior filled with sand. On the assumption that the high temperature reached during the casting process would have emptied all the traps in the sand crystals and set the thermoluminescence clock to zero, thermoluminescence dating became possible. After painstaking selection under a microscope, the initial measurements' 211 were made using no more than six grains of the sand (zircon crystals). On the basis of these and later measurements, the age of the horse was established to be 2250 ± 210 years, thus establishing it clearly as genuine. 202 PHYSICS IN CANADA J u l y / A u g u s t 1998 This is a fortunate circumstance for the problem of h u m a n origins. For the archaeologists of the late 19th century the only available evidence about human origins lay in caves in France and Germany, in which long occupation by early people had left stratified deposits containing skeletons. One of these skeletons, found in a cave in the valley of the Neander River in Germany in 1856, aroused intense astonishment and curiosity. The large size and apparently "brutish" characteristics of the bones (since reappraised as a consequence of more recent examination) confounded those for whom the Biblical description of the Creation provided a sufficient account of human origins. Such Neanderthal remains then started appearing over much of Europe, notably in France. In the many stratified cave deposits in France the Neanderthal remains lay below (thus pre-dating) the skeletons of people like us, to w h o m were given the name Cro-Magnon. In Western Europe the replacement of the Neanderthal people by the CroMagnon people seemed complete and relatively instantaneous somewhere between 30,000 and 40,000 years ago, thereby raising obvious questions about the relationships between the two types of people. They are very similar - both qualify as Homo sapiens, one being H o m o sapiens neanderthalensis, while we are Homo sapiens sapiens. But did w e evolve out of Neanderthal people? Or did the two strains of Homo sapiens evolve separately, only to have Cro-Magnon people ultimately outlive Neanderthal people because of some evolutionary advantage? ARTICLE D E F O N D Much depended on the apparent evidence from the stratified deposits in the Western European caves that the Neanderthal people antedated the Cro-Magnon people and were apparently replaced by them. If, however, one could obtain absolute dates for a wide variety of Neanderthal and Cro-Magnon remains, the situation would be greatly clarified. Fortunately, a technique for such dating is available. Tooth enamel contains a crystalline material, hydroxyapatite. As an insulating crystal, hydroxyapatite stores radiation damage over prolonged periods, and the accumulation of trapped electrons can be detected by the very convenient technique of electron spin resonance. This technique measures directly the number of trapped electrons in the crystal without the requirement to empty the traps through heating or other perturbation. The application of esr to dating was first developed by Ikewa at Yamaguchi University' 221 , and has now become common for archaeological purposes. Fig. 12 shows the esr signal from a recent specimen in comparison with that from an ancient specimen, illustrating clearly the increase in the esr signal with specimen age. 2.013 2.0W 2005 2.000 (995 Fig. 12 Esr signals (on the s a m e vertical scale) f r o m an ancient specimen (below) and a m o d e r n specimen (above). To apply this method to the N e a n d e r t h a l / Cro-Magnon problem, R. Grtin (Cambridge University) and C.B. Stringer (Natural History Museum, London) measured the ages of a large ( A R C H A E O L O G I C A L PROBLEMS...) number of teeth from Cro-Magnon and Neanderthal skulls that came from a wide variety of locations in Europe, the Middle East and North Africa1231. The results were astonishing and illuminating. Not only did the ages of the two groups overlap, they did so right back to the earliest dates obtained. In fact, the earliest skull (~130,000BP) belonged to the Cro-Magnon, not the Neanderthal group. It is now apparent that, whatever the relationship was between the two groups, the old concepts of the cultural sequence must be abandoned. It is clear that the two groups co-existed. Whether one group arose out of the other or whether the two were the outcomes of separate evolutionary lines remains a topic for debate, but at least the dating measurements have made clear the requirements for future models. WHERE D O T H I N G S COME FROM? Not all problems in the study of the past relate to chronology. For the purpose of determining cultural influences or connections between different peoples, it is sometimes just as important to know the source of materials or artefacts. Often such origins can be determined from elemental analysis of the materials involved, and many techniques have been used. For example, isotopic analysis has been used to track metals from their original ores, and many forms of spectral or chemical analysis have been used to characterise materials as diverse as Palaeolithic flint tools and Impressionist paintings. To illustrate the archaeological application, we shall describe just one example out of the countless numbers that are available. In the early centuries of the third millenium BC there arose in SW England a group of Early Bronze Age tribal chieftains who gained such wealth and power that, to the present day, their burial mounds are a prominent feature of the landscape in Wiltshire and Hampshire. Stuart Piggott styled them the "Wessex Chieftains" on the basis of the richly equipped graves in which they were buried. Apart from the magnificent gold objects in the graves, these Wessex Chieftains had a taste for jet jewelry that included buttons, buckles, belt-loops and other objects. Now, although there are adjacent sources of other jet-like materials such as shale or cannel coal that are visually very similar to jet, the only significant source of true LA PHYSIQUE AU CANADA juillet à août, 1998 203 FEATURE ARTICLE ( A R C H A E O L O G I C A L PROBLEMS. ..) jet is located several h u n d r e d miles away, on the coast of Yorkshire near Whitby. True jet, valued for its uniform, fine structure, is scarce because it is formed only when a trunk of the Carboniferous tree fern falls, waterlogged, on to clean, pure sand to become carbonized, instead of into the swampy, m u d d y environment that formed the less-pure coal seams. Consequently, if an item is found in a grave on Salisbury Plain and is identified as jet, the implication is automatically created that it was imported from 300 miles away, an assertion of some significance for the consideration of Early Bronze Age trade. To distinguish between true jet and other jet-like materials, it is natural to turn to elemental analysis, for which many techniques are available. Of these, by far the most convenient for archaeological purposes is X-ray Fluorescence Spectrometry, since it is completely non-destructive and non-invasive. The physical principles are simple and are illustrated in the familiar diagram for X-ray emission shown in Fig. 13. determination of the atomic composition of the sample is easy. This has provided a tool of immense usefulness in the examination of archaeogical and artistic objects, providing invaluable information about the origin of materials, and also very frequently providing definitive information about authenticity. The actual apparatus used in the Oxford laboratory is shown in Fig. 14. A primary X-ray beam is directed through a collimator on to the surface of the specimen. The resulting fluorescent X-rays are received by a lithium-drifted silicon detector and analysed using a standard pulse height analyser to obtain the fluorescent spectrum. o M. K. Fig. 13 Atomic energy level d i a g r a m s h o w i n g the transitions involved in X-ray production. Excitation of an electron in the K-shell or the L-shell of an atom will result in the emission of one or more of the lines of the K-series or L-series of the X-ray spectra of the atom, and since the wavelengths of these emitted lines are characteristic of the atom, 204 PHYSICS IN CANADA J u l y / A u g u s t 1998 When XRF analysis was applied to calibration specimens of known origin, it was apparent immediately that complete discrimination between true jet and other jet-like materials was provided by the element iron. No true jet contained iron, but all other jet- like materials did contain iron, as illustrated in the spectra shown in Fig. 15. In this way, it was possible to examine all the material from the Wessex Chieftain graves and discriminate immediately between material that had been imported and material that was made of less costly local substitutes' 241 . More recently, it has been found ARTICLE D E F O N D that other, smaller deposits of true jet do appear elsewhere than Whitby, but more refined analysis has been able to distinguish between these products and the Whitby jet so that valid statements about trade routes can still be made. Matchbox ' 1 2 9 4 5 Il II B 7 I • i i F» Zn 10 11 13 13 U 15 H 17 1 * W 20 reminder to all others w h o might believe they had a claim on the territory. Time passed, title to the property fell into other hands, and in 1936 a modern Californian d u g u p in her garden a brass plate engraved with exactly the text described in the biography. To no one's surprise, the authenticity of the plate has frequently been questioned and, as soon as XRF techniques had been developed adequately, examination of the plate was undertaken by two laboratories, the Lawrence Berkeley Laboratory in California' 251 and the Laboratory for Archaeological Science in Oxford' 26 '. The results were unequivocal. The following Table shows the composition of three samples from the Drake Plate in comparison with the composition of samples of dated brass from the sixteenth century. The concentrations of the major components (copper and zinc) are not particularly significant because they are variable and not characteristic of particular historical periods. The concentrations of the trace impurities such as lead and tin, on the other hand, make the situation clear. In the Drake Plate, these concentrations are below the limit of detectability, while in all historical material the concentrations are appreciable. Modern brass, obviously, is made from highly-refined raw materials, while mediaeval brass, impure to begin with, was frequently recycled and acquired substantial concentrations of impurities. J«t K C*Tiv ( A R C H A E O L O G I C A L PROBLEMS...) KeV i l l y—'. • Rt) 5r Zr "l^ I Mo (Tubal Inelastic Scatter To anyone who still wishes to believe in the authenticity of the Drake Plate, the further point that its thickness corresponds exactly with that of No. 8 gauge brass of the American Wire Gauge standard is presumably only a matter of coincidence. Fig. 15 X-ray fluorescence spectra of jet (bottom curve) a n d other jet-like materials s h o w i n g the effectiveness of iron as a discriminator. We shall close with two quick examples of the effectiveness of XRF in examining historical material. In the 1570's Sir Francis Drake was sailing around the world to provide an English response to the extensive Spanish occupation of Central and South America. He was sailing u p the Western coast of what is now California w h e n he landed near the present-day San Francisco. In front of the doubtless bemused native inhabitants he proclaimed sovereignty over the territory for Queen Elizabeth. His ship's artificers were so impressed with this achievement that, as narrated by his biographer, they formed a plate out of brass, engraved on it the text of Sir Francis' proclamation and mounted it on land to serve as a Finally, Fig. 16 shows the well-established historical variation of silver content in Roman coins of the imperial period. From a high value in the prosperous early days of the Empire, the decline during the second and third centuries reflects the political and military turmoil of the period and the increasing disorder in imperial management. Fig. 16 also shows the front and back faces of a silver coin minted during the time when Gordianus III was emperor. Gordianus became emperor at the young age of 13 in the year 238AD and was killed by his troops while on campaign against the Persians in the year 244. LA PHYSIQUE AU CANADA juillet à août, 1998 205 FEATURE ARTICLE ( A R C H A E O L O G I C A L PROBLEMS. ..) TABLE 1 Composition of Three Samples f r o m the Drake Plate in Comparison with the Composition of Samples of Dated Brass from the Sixteenth Century Zinc % Copper % Lead % Tin % Sample 1 35.8 64.2 <0.05 <0.01 Sample 2 34.5 65.5 <0.05 <0.01 Sample 3 35.0 65.0 <0.05 <0.01 1520 23 74.5 0.8 0.16 1559 28 70.5 1 0.4 1560 21.5 74 1.3 3.0 1567 29 69 1.5 0.5 1575 31.5 67.5 0.7 0.3 1584 17 81 0.3 1.5 1586 22 74 1.8 2.0 1586 21 78.5 0.4 0.1 1593 21 78.5 0.4 0.1 1598 23 73.5 0.7 2.8 Drake Plate Comparison Material 206 PHYSICS IN CANADA Dates July/August 1998 ARTICLE D E F O N D A l t h o u g h not m a r k e d , as are o u r coins, w i t h actual dates, t h e inscriptions o n R o m a n coins are specific, a n d this inscription enables u s to k n o w that the coin w a s m i n t e d d u r i n g t h e f i r s t t h r e e m o n t h s of t h e y e a r 2 4 0 A D . N o p r o b l e m of d a t i n g e x i s t s , o b v i o u s l y , b u t t h e c o i n o f f e r s a g r a p h i c i l l u s t r a t i o n . E x p o s u r e of t h e c o i n to o n e ' s X R F set f o r o n l y a f e w s e c o n d s is s u f f i c i e n t t o tell u s t h a t t h e c o m p o s i t i o n of t h e c o i n is a p p r o x i m a t e l y 50:50 s i l v e r a n d c o p p e r , i n c o n f o r m i t y w i t h t h e v a l u e s h o w n i n Fig. 16 f o r t h a t d a t e . S u c h a m e a s u r e m e n t , t h e r e f o r e , a l l o w s u s t o h o l d in o u r h a n d s d i r e c t e v i d e n c e of t h e d e c l i n i n g f o r t u n e s of t h e R o m a n E m p i r e in t h e t h i r d c e n t u r y A D , a n d r e m i n d s u s t h e r e b y of t h e e n o r m o u s e n h a n c e m e n t of o u r historical a w a r e n e s s that the sciences can offer. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. REFERENCES 1. B o w m a n , S. (ed), Science and the Past, University of Toronto Press (1991) 2. H e n d e r s o n , J. (ed), Scientific Analysis in Archaeology and its Interpretation, O x f o r d University Committee for Archaeology (1989) 3. Leute, U., Archaeometry, V C H Verlagsgesellschaft (1987) 4. Aitken, M.J., Science-Based Dating in Archaeology, L o n g m a n (1990) 5. Aitken, M.J., Thermoluminescence Dating, Academic Press (1985) C O M I N G IN SEPTEMBER. 19. 20. 21. 22. 23. 24. 25. 26. ( A R C H A E O L O G I C A L PROBLEMS...) Libby, W.F., Science, 133, 621 (1961) Ferguson, C.W., Science, 159, 839 (1968) Berger, R., Suess, H.E., Radiocarbon Dating, University of California Press (1970) Renfrew, C., British Prehistory, A New Outline, D u c k w o r t h (1974) Renfrew, C., Archaeology and Language, The Puzzle of Indo-European Origins, Penguin Books (1989) Nelson, D.E., Korteling, R.G., Stott, W.R., Science, 198, 507 (1977) Bennett, C.L., Beukens, R.P., Clover, M.R., Gove, H E., Liebert, R.B., Litherland, A.E., Purser, K.H., Sondheim, W.E., Science, 198, 508 (1977) Hedges, R.E.M., Archaeometry, 23, 3 (1981) D a m o n , P.E., et al., Nature, 337, 611 (1989) Eijgenraam, F., A n d e r s o n , A., Science, 254,187 (1991) Roberts, D., National Geographic, 183, 36, (June 1993) Spindler, K., The Man in the Ice, H a r m o n y Books (1993) Hedges, R.E.M., Housley, R.A., Bronk, C.R., van Klinken, G.J., Archaeometry, 34, 346 (1992) Huntley, D.J., Godfrey-Smith, D.I., Thewalt, M.L.W., Nature, 313,105 (1985) Aitken, M.J. Archaeometry, 31, 2 (1989) Z i m m e r m a n , D.W., Yuhas, M.P., Meyers, P., Archaeometry, 16,19 (1974) Ikewa, M „ Archaeometry, 20,147 (1978) G r û n , R„ Stringer, C.B., Archaeometry, 33,153 (1991) Pollard, A.M., Bussell, G.D., Baird, D.C., Archaeometry, 23,139 (1981) Michel, H.V., Asaro, F„ Archaeometry, 21, 3 (1979) Hedges, R.E.M., Archaeometry, 21, 21 (1979) A VENIR E N SEPTEMBRE.... LA PHYSIQUE SPACE, WEATHER, AND THE ENVIRONMENT T h e m e I s s u e of PHYSICS CANADA avec L'ESPACE, LE TEMPS ET L'ENVIRONNEMENT IN S e e i n s i d e b a c k c o v e r of t h i s i s s u e f o r m o r e d e t a i l s a n d an order f o r m for extra copies. AU CANADA la t h è m e d e : V o u s t r o u v e r e z d e p l u s a m p l e s r e n s e i g n e m e n t s et un bon de c o m m a n d e pour des revues s u p p l é m e n t a i r e s à la t r o i s i è m e c o u v e r t u r e d e c e t t e revue. LA PHYSIQUE AU CANADA juillet à août, 1998 207 F E A T U R E A R T I C L E ( A HISTORY O F T H E DEPARTMENT. ..) A HISTORY OF THE DEPARTMENT OF PHYSICS A N D ASTRONOMY AT THE UNIVERSITY OF VICTORIA by G.R. Mason and H.W. Dosso T Physics has been taught as a first-year subject since he Department of Physics and Astronomy at the earliest days of Victoria College; but a Department the University of Victoria is perhaps best of Physics as such was not formed until the 1950s. known at present for its strengths in W.H.(Bill) Hughes was in charge of Physics courses subatomic physics research at TRIUMF and CERN, from 1944 until his retirement and in astrophysics through in 1953. He hired John research programs at various Climenhaga (PhD, Michigan), observatories around the Undergraduate program options fresh with his MSc from the world. During its 35 years, currently include General, Major, University of Saskatchewan however, the Department in 1949, and, together with has also enjoyed a reputation and Honours degrees in Physics, part-time lab instructor, for excellence in research in and in Astronomy; and in Cecily Girvan, they taught geophysics, plasmas, and combined programs of physics the first two years of Physics. shock wave studies. The with astronomy, mathematics, When John Climenhaga took major research areas develtwo years leave-of-absence oped in the department in computer science, earth sciences, from 1954 to 1956 to get his part because of close collaand ocean sciences. PhD (in astronomy) courses boration with world-class were taught by temporary research establishments in instructors Andy Hill and David McLay and near Victoria. These include the Dominion Astrophysical Observatory (DAO), TRIUMF in Vancouver, the Defence Research Establishment The next few years, from 1957 to 1963, saw the Pacific (DREP, n o w closed down; formerly the Pacific transition from a two-year college to an independent Naval Laboratory, PNL), the Pacific Geoscience undergraduate university. John Climenhaga served as Centre (PGC), and the Institute of Ocean Sciences Head of the Department of Physics from this time (IOS). until 1969, when he became Dean of the Faculty of Arts and Science. The planning of the four-year THE EARLY DAYS physics programs was carried out largely by Harry Dosso (PhD, Brit. Col.), hired in 1957 upon completing Although the University of Victoria was established BEd and MSc degrees at UBC, and Gerhart Friedmann as an independent university in 1963 the institution (PhD, Brit. Col.), hired in 1958. Also hired during had existed prior to that date as Victoria College, these interim years were Harbhajan Sandhu (PhD, which was founded in 1903 as an affiliate of McGill Brit. Col.), David Rankin (PhD, Alta), Gren Mason University. Victoria College became associated with (PhD, Alta), and Michael Pearce (PhD, Brit. Col.), in the University of British Columbia in 1920, five years 1961,1961,1962, and 1963, respectively. after that institution had become established in With the emergence of the University of Victoria in Vancouver, and over the years, earned a solid reputation for excellence in teaching. Many of its graduates have gone on to do well at various G.R. M a s o n a n d H.W. Dosso are Professors in the Physics Department of the University of Victoria, British universities and other establishments, and have had Columbia subsequent illustrious careers. 208 PHYSICS IN CANADA July/August 1 9 9 8 ARTICLE DE F O N D ( A HISTORY O F THE DEPARTMENT...) 1963, the institution moved to a new campus formerly occupied in part during the second world war by a small armed services camp. Although the land for the new campus was largely undeveloped with some farm use, there were several old wooden military buildings. An old airplane hangar was renovated and used for many years as the gymnasium for the university; wooden military huts served as temporary offices and physics lab laboratory space;, and, an old officers' mess was used as the Faculty Club for some twenty years. The first permanent structure on the Gordon Head campus was the Clearihue building, completed in October of 1962; this building was named after Judge J. B. Clearihue, one of the students in the first, 1903, class of Victoria College, and one of the strong advocates for an independent University of Victoria. The Clearihue building was built as a classroom block, and retains that use, but it now stands as just one side of a much larger building q u a d quadrangle containing faculty offices and the university's Computing Centre. The second permanent building for the new campus was the Elliott building, which was occupied for the first time in December 1963. The building initially housed the Departments of Physics, Chemistry, and Biology, each with a full floor to itself, and with some sharing of the basement level for research space. A partial fourth floor was included in the building due to the foresight and persistence of John Climenhaga. Initially it had no officially designated use; but, as anticipated by Climenhaga, it eventually became the laboratory space and offices for the nucleus of an astronomy group within the department. It now also serves as the base for the Climenhaga Observatory, utilizing a 20-inch reflector telescope. The Biology Department moved into a new building of its own in 1974, and the Elliott building has since been shared between the Departments of Physics and Astronomy and of Chemistry. G R O W T H OF THE DEPARTMENT The 1960s were years of rapid growth; the numbers of students in the university increased from 800 in 1963 to some 5000 in 1970 (and, the "head count" for 1997/98 was 15000). The number of full-time faculty in the department rose from 5 in 1963 to 23 in 1970, to 25 in the 1980s, and now seems to have settled in at about 20. A list of regular faculty members is shown in Table I together with the years of service in the Department. Figure 1 shows the Department Chairs (formerly called "Heads"), and a few other prominent members of the Department. Undergraduate program options currently include General, Major, and Honours degrees in Physics, and in Astronomy; and in combined programs of physics with astronomy, mathematics, computer science, earth sciences, and ocean sciences. In 1998, a new option, that of Physics, was introduced to the Electrical Engineering program. The total numbers of graduates of the Department, in five-year groups, are shown in Table II. Those university medal winners who graduated from the department are shown in Table III. And, since the reputation of a department is often seen through its graduates, a group photo of one of our memorable graduating classes is shown in Figure 2; there are many more. (NRC physicists, in particular, will recognize Bob McKellar, who won the CAP Herzberg Medal in 1982.) The Department takes particular pride in its Co-operative education program which became an option at UVic for the first time in 1976, when the Departments of Physics and of Chemistry started their respective co-op programs. These programs were strongly supported by the then (1975) new university President, Dr Howard Petch (PhD, UBC), a solid state physicist who came to UVic from the University of Waterloo. Physics Co-op has proven to be very popular and is chosen by more than 50 percent of our physics undergraduates. Students are placed on work terms throughout Canada and in many other countries, including the USA (e.g. Hawaii and California), Switzerland, Germany, and Japan. The Physics Co-op program was initially managed by a group of Physics faculty members with Harry Dosso as the Physics Co-op Director. In 1979 Roel Hurkens (MSc, Tor) joined the department as Physics Co-op Coordinator, followed by Peter Cross (BSc, UVic) in 1988, u p to the present. Faculty members continue to have a significant involvement through site visits, assessments of students, and the marking of students' work-term reports. LA PHYSIQUE AU CANADA juillet à août, 1 9 9 8 209 F E A T U R E A R T I C L E ( A HISTORY O F T H E DEPARTMENT. ..) ' TABLE I: LIST OF FACULTY MEMBERS with years of service in the department | William H. Hughes 1944-1953 John T. Weaver 1966-1998 Chris J. Pritchet 1982- John L. Climenhaga 1949-1982 Chi-Shiang Wu 1967-1994 Alan Astbury 1983- Harry W. Dosso 1957-1997 Fred I. Cooperstock 1967- Richard K. Keeler 1983- Gerhardt B.Friedmann 1958-1990 Donald E. Lobb 1967-1998 Don A. VandenBerg 1986- David Rankin 1961 - 1 9 6 3 J. Anthony Burke 1968- Dale B. Pitman 1990-1996 Harbhajan S. Sandhu 1961 - 1 9 9 7 Reginald M. Clements 1968-1996 Christopher J.R.Garrett 1991 - Grenville R. Mason 1962- F. David A. Hartwick 1968- Michel Lefebvre 1991 - R. Michael Pearce 1963 -1980 Charles E. Picciotto 1968- Ann C. Gower 1993- Walter M. Barss 1964-1982 George A. Beer 1969- J. Michael Roney 1996- Harry M. Sullivan 1964-1986 James P. Elliott 1969-1978 Arif Babul 1997- John M. Dewey 1965-1995 Jeremy B. Tatum 1969- Robert V. Kowalewski 1997- Colin D. Scarfe 1965- Robert E. Horita 1970- Julio Navarro •998- Judith Robinson 1966-1967 Howard E. Petch 1975-1990 Lyle P. Robertson 1966-1997 Arthur Watton 1975- TABLE II: NUMBERS of GRADUATES per five-year interval Years PhD MSc BSc (Total) (Honours) (Major) (General) 1964-1968 - 4 114 23 27 64 1969-1973 5 29 122 31 91 - 1974-1978 11 20 70 31 39 - 1979-1983 10 15 89 40 49 - 1984-1988 5 32 139 45 94 - 1989-1993 17 28 84 22 62 - 1994-1998 24 14 110 38 64 a TABLE III: GOVERNOR-GENERAL and JUBILEE MEDAL WINNERS at the University of Victoria from the Department of Physics and Astronomy At the Bachelor level: 1965 GOUGH, Richard Arthur (GG) 1979 FAWCETT, John (GG) 1988 CHARLESWORTH, Brian Douglas (GG) 1966 MATTHEWS, John Albert (GG) 1982 DOSSO, Stan (Jubilee) 1989 ZIBIN. James P. (Jubilee) 1973 DAVIS, Kenneth George (GG) 1983 WEAVER. Andrew (GG) 1990 MacFARLANE, W. Andrew (GG) 1975 LAUKANEN, Ethan (GG) 1985 SPENCER, Philip (GG) 1994 HUNTER, Chris (GG) 1976 McCALL, Marshall Lester (GG) 1986 JENSEN, Erik (Jubilee) 1996 ANDERSON, Jared (GG) 1977 BERNARD, John (GG) 1987 VERRALL, Jane Andrea (GG) 1997 Luc Simard (Supervisor: C.J.Pritchet) Gold Medals for Ph D thesis: 1992 210 Ben Dorman (Supervisor: D.A.VandenBerg) PHYSICS IN CANADA J u l y / A u g u s t 1998 A R T I C L E DE F O N D ( A H I S T O R Y OF THE DEPARTMENT...) Fig. 1 D e p a r t m e n t H e a d s , Chairs, and a Few Others - Left to right, f r o m the top: J.L.Ciimenhaga (Head 1957-69), H.W.Dosso (Head 1969-75), R.M.Pearce (Chair 1975-80), J.T.Weaver (Chair 1980-1988), L.P.Robertson (Chair 1988-93), J.M.Dewey (Chair 1993-95), C.J.Pritchet (Chair 1995-98), .E.Picciotto (Chair 1998- ), D.A.VandenBerg (B.C. Science Gold Medal winner, 1988), A. Astbury (FRS, FRSC, TRIUMF, Director 1994-, R.M.Pearce Professor), H.E.Petch (UVic President 1975-90), C.J.R.Garrett (FRS, FRSC, L a n s d o w n e Professor). LA PHYSIQUE AU CANADA juillet à août, 1998 211 FEATURE A R T I C L E ( A HISTORY O F T H E DEPARTMENT. ..) Fig. 2 The Honours Physics Class of 1966 - Left to right: Hugh Pite, Sydney Bulman-Fleming, Glen Vickers, John Matthews, Bob McKellar, Bob Johns, John Tippett, and Robin Louis. Department members continue to enjoy the support services provided within the department by an electronics shop, a machine shop, demonstration preparation room, a departmental research computer, and a computer terminal room. Undergraduate physics and astronomy laboratories have been developed and managed through the excellent service provided respectively by Don Stenton (BSc, Brit.Col.-Vic.Coll.), w h o joined the department in 1963, and Russ Robb (BSc, Calg.), w h o joined in 1982. In the early years of the department Stenton also processed the financial statements for the department, set u p and developed lecture demonstrations, and provided photographic services for faculty research. Astronomy courses have been taught in the university since 1958 when astronomers from the near-by Dominion Astrophysical Observatory (DAO) gave courses on a part-time basis. When Colin Scarfe (PhD, Cantab.) arrived in January, 1965, he taught the second halves of first and third-year astronomy courses that had been started in the first (fall) term by Drs Jean Petrie and Alan Batten, respectively, of the DAO. To facilitate the development of astronomy programs, the one-person department of Colin Scarfe was incorporated with the Physics department in 1967. Within two years, Tony Burke (PhD,Harvard), David Hartwick (PhD, Tor), and Jeremy Tatum (PhD,London) joined John Climenhaga and Colin Scarfe to form an astronomy group within the Physics 212 PHYSICS IN CANADA J u l y / A u g u s t 1998 department. Undergraduate and graduate programs in astronomy were soon developed. Fred Cooperstock (PhD, Brown) joined the Department in 1967 with expertise in general relativity and cosmology; he has continued research in his field, and also has maintained a close association with the astronomy group. When Arthur Watton (PhD, McMaster) joined the Department in 1975, he and Harb Sandhu used NMR to study the molecular properties of solids and liquids. Harb Saridhu had been studying the effects of radiation on salamanders with Gerhart Friedmann who, at the time, worked half-time as a medical physicist at the Victoria Jubilee Hospital. It is interesting to note that John Scrimger (PhD, Tor.), who worked as Head of the Physics Department at the Victoria Cancer Clinic from 1993 until 1997, had also worked as a physics lab instructor at Victoria College for the fiscal year 1959/60. The Physics Department was one of the first in the university to offer a graduate program, starting in 1966. One of the first graduates was Janet Ng, who received her MSc in Physics in 1967 under the supervision of Gren Mason and Mike Pearce for analysis of cosmic-ray neutron data. The first PhD degree in the Department was awarded to Dexter Booth, who graduated in 1970 under the supervision of Fred Cooperstock with a thesis entitled "Gravitational Radiation, Gravitational Induction and the Two-body Problem". Since 1966, the Department ARTICLE DE F O N D ( A HISTORY O F THE DEPARTMENT...) has graduated 72 PhD and 142 MSc students. in 1969, but left the Department in 1978 to take a position with an engineering firm in California. RESEARCH IN GEOPHYSICS A N D THE PHYSICS OF FLUIDS Geophysics and the physics of fluids were among the first research areas to develop in the Department. In fact, one of the large labs in the basement of the Elliott building was designed to accommodate an electromagnetic modelling facility planned for use by David Rankin and Harry Dosso. Shortly after the Department moved into the new Elliott building, however, David Rankin moved to the University of Alberta. Harry Dosso then took over the laboratory, and developed a unique analogue modelling technique for studying electromagnetic induction in the earth and oceans, contributing significantly to the understanding of the geomagnetic coast effects in many regions of the world. John Weaver (PhD, Sask), came in 1966 from research in electromagnetic induction at the Pacific Naval Laboratory studying the highly mathematical aspects of electromagnetic induction in the earths and oceans, and has made major contributions in developing analytical and numerical techniques used world-wide. Other areas of geophysics were added in 1964 when Harry Sullivan (PhD, Sask) arrived and set u p a station to monitor the presence of K, Na, and Li ions in the upper atmosphere; and in 1968 when Monty Clements (PhD, Sask) arrived and researched plasmas in space physics and in spark plugs for internal combustion engines. Bob Horita (PhD, Brit Col) joined the Department in 1970 and continued his earlier studies of plasma wave phenomena in the ionosphere and magnetosphere, as observed by satellites, rockets and ground stations. Walter Barss (PhD, Purdue), John Dewey (PhD, London), and Jim Elliott (PhD, Stanford) joined the Department in 1964,1965, and 1969, respectively. Walter Barss designed and developed an underwater acoustics modelling laboratory based upon a large water tank situated in the basement of the Elliott building. John Dewey, coming from the Defence Research Laboratory at Suffield with considerable experience in shock w a v e studies, developed a laboratory to study the gas dynamics of shock and blast waves using photographic and holographic techniques. Jim Elliott (PhD, Calif) began a research program in theoretical gas dynamics when he arrived A very significant development at UVic occurred in the latter part of the 1980s when the Department Chair, John Weaver, motivated the Department and the senior University administration to explore the possible establishment of a research centre to formalize and enhance the collaboration between scientists at the university and those in local government laboratories in the fields of earth and ocean physics. A steering committee was appointed consisting mainly of scientists from local federal and provincial laboratories, but chaired by Harry Dosso from the Physics Department. This lead to the formation of CEOR (Centre for Earth and Ocean Research) in 1987 with R.E. (Bob) Stewart (PhD, Cantab.) as the first (interim) Director. The second (and current) Director, Chris Barnes (PhD, Ott.), with the goal of providing new programs in the fields of earth and ocean sciences and also of obtaining adequate f u n d i n g for research, initiated SEOS (The School of Earth and Ocean Sciences). Both CEOR and SEOS, with Chris Barnes as Director of each, are well established and, indeed, the undergraduate programs in SEOS are popular with students. Provision was made for joint appointments between SEOS and Physics, and Chris Garrett (PhD, Cantab.) was appointed in 1990 as Lansdowne Professor in Ocean Physics. George Spence (PhD, UBC), a seismologist who had joined the department under the NSERC University Research Fellow program in 1988, transferred in 1992 to SEOS where the research efforts in geophysics are expanding. RESEARCH IN SUB-ATOMIC PHYSICS Nuclear and particle physics research began in the Department with the construction by Pearce and Mason in 1964 of a Cosmic Ray Neutron "Super Monitor" on the roof of the Elliott building. The monitor had been designed by Hugh Carmichael and Mike Bercovitch of the Chalk River Nuclear Laboratories where Mike Pearce had a distinguished career in reactor physics before coming to UVic. The monitor was one of a world-wide network and was operated by Pearce and Mason for ten years. In the mid 1960's, under the leadership of Mike Pearce the nuclear physics group became committed to the TRIUMF project on the UBC endowment lands in LA PH YSIQUE AU CANADA juillet à août, 1998 213 F E A T U R E A R T I C L E ( A HISTORY O F T H E DEPARTMENT. ..) Vancouver. UVic is one of the four founding universities, and provides three of the twelve members of the TRIUMF Board of Management and two members of the Operating Committee. Mainly because of the TRIUMF project, Lyle Robertson (PhD, Brit.Col.), George Beer (PhD, Sask), and Don Lobb (PhD, Sask) joined the department in the latter half of the 1960s. Theoreticians, Charles Picciotto (PhD, Calif.) and Chi-Shiang Wu (PhD, West. Res.), also joined the Department at that time. These five physicists plus Gren Mason and Mike Pearce, both of w h o m had been hired a few years earlier, comprised the TRIUMF group at the University of Victoria in 1970. Because distance and the intervening Strait of Georgia made access to TRIUMF relatively difficult for the UVic group, they chose to work on projects that could proceed independently of the main construction of the cyclotron and associated buildings; they chose to work on beamlines and magnets, and on targets for the production of secondary beams of pions and muons. Much of this work took place in the basement of the Elliott building at UVic, and in two modular trailers which were brought in specifically to accommodate the quickly expanding group of physicists, engineers, and technicians. This group included Paul Reeve and Terry Hodges from the Rutherford Laboratory in Oxfordshire, England, Roland Cobb (PhD, Rochester) w h o is now a professor at the University College of the Cariboo in Kamloops, and Douglas Bryman (PhD, Virginia Poli. Inst.), John Vincent (MSc, W m & Mary), and Art Olin (PhD, Harvard), all of w h o m are n o w Senior Research Scientists at TRIUMF. When TRIUMF became operational in 1974 experiments by members of the Victoria group included measurements of pion-production cross-sections, branching ratios for the decay of the pion, measurements of energy shifts and widths of pionic x-rays, and n-p scattering measurements with the BASQUE group. When the TRIUMF proton beam intensity w a s increased over the years, measurements were also m a d e on muonic atoms, of limits for the possible conversion of m u o n i u m to anti-muonium, and of rates of processes involving muons in targets of solid hydrogen. A time-projection chamber was built at TRIUMF in the 1980s, largely through the efforts of Doug Bryman, to measure rare decays of the muon. 214 PHYSICS IN CANADA J u l y / A u g u s t 1998 This research was extended to BNL Brookhaven National Laboratory, USA, in the 1990s, and resulted in the discovery of a rare kaon decay in 1997. Beer, Mason, and Olin also extended their research to KEK, Japan, for measurements of X rays from kaonic-hydrogen; and Beer and Robertson participated in the ASTERISK experiment at LEAR, CERN, Geneva, Switzerland measuring X rays from pbar print as p -p atoms. The theoretical efforts of Charles Picciotto have focused on rare decays and CP violation. The year 1980 was a turning point for the group and for the Department; that year, Mike Pearce, who was the UVic TRIUMF group leader and Physics Department Chair, died after battling amyloidosis for a year. In recognition of his very substantial contributions to the Department, to the University, and to TRIUMF, a Professorship was set u p in his honour; Alan Astbury (PhD, Liverpool) became the R M Pearce Professor of Physics in 1983. Alan had been co-spokesman for the UA1 experiment at CERN which discovered the Z0 particle, and for which Carlo Rubbia received the 1983 Nobel prize in Physics; Alan has been the Director of TRIUMF since 1994. When Alan Astbury came to UVic, he brought with him a colleague from the UA1 experiment, Richard Keeler (PhD, Brit Col UBC), and several graduate students. Together they have built u p a strong high energy physics group whose members now work on OPAL at CERN, on BABAR at SLAC in California, and on building hadronic calorimeters for the ATLAS detector to be used at the LHC (Large Hadron Collider) when it becomes operational at CERN, Switzerland. In the latter 1980s the group worked on SLD at SLAC, but switched to the OPAL group at LEP when the physics advantages at CERN became so overwhelmingly clear. Canadian participation in ATLAS is being spearheaded by Michel Lefebvre (PhD, Cantab.), and a very substantial construction project is underway in the basement of the Elliott building to construct large feedthroughs for the ATLAS endcap calorimeter cryostats. Two of the newer faculty, Mike Roney (PhD, Carleton) and Bob Kowalewski (PhD, Cornell), are working on BABAR at SLAC, as well as continuing their participation in OPAL at CERN. Thus, over the years, the subatomic physics group has shifted the focus of its research from intermediate energy physics at TRIUMF to high A R T I C L E DE F O N D ( A H I S T O R Y O F THE DEPARTMENT...) energy, elementary particle physics at CERN, Geneva, and at SLAC, California. The success of the group has been enhanced greatly through the work of Randy Sobie (PhD, Tor), an IPP Scientist working at UVic, Alan Honma (PhD, Stanford), an internationallyrecognized UVic TRIUMF Research Scientist, Janis McKenna (PhD, Tor), an IPP Scientist w h o worked at UVic from 1992 to 1994, and w h o is now an Associate Professor at UBC, and Rob McPherson (PhD, Princeton), an IPP Scientist working for the UVic group at CERN. Those interested in learning more about the details of particle experiments, high energy accelerators, and the many associated acronyms may wish to refer to the March/April 1994 issue of Physics in Canada, which contains many articles describing Canadian Particle Physics. A S T R O N O M Y RESEARCH Just as the subatomic physics group has strengthened in the 1980s and 90s, so also has the astronomy group. Both Chris Pritchet (PhD, Tor.) and Don Vandenberg (PhD, ANU) joined the department in 1982, and Ann Gower (PhD, Cantab.) formally became a regular faculty member in 1993, although she had taught on a sessional basis for many years before that. Arif Babul (PhD, Princeton) joined the department in July 1997; and, Julio Navarro (PhD, Cordoba) arrived in 1998. The department now has one of the strongest astrophysics groups in Canada, with research strengths in the areas of observational cosmology, evolution of galaxies and modelling of the evolution of stars. However, as was stated earlier, astronomy has been an important part of the Department right from the early days of the university. John Climenhaga pioneered research into the carbon 12/13 ratios in cool giant stars; Colin Scarfe has been studying radial velocities of binary stars using telescopes at the nearby DAO. Ann Gower has been studying the structure of radio galaxies using the radio-telescope near Penticton, B.C. A vigorous program of astrometry of comets and asteroids w a s started at the Climenhaga Observatory in the early 1970s, which soon developed into one of the leading programs of its kind in the world. Although the increasing level of light pollution on campus has meant the cessation of research observations with the University's telescopes, the astrometry program is continued by Balam using the Plaskett telescope of the DAO. The program concentrates on observations of newly-discovered Earth-approaching asteroids, and it currently produces follow-up observations of more of these objects than any other observatory in the world. As a result of the renown of this work, the International Astronomical Union has bestowed immortality on four members of the Department by officially naming asteroids (3034), (3748), (3749) and (6532) Climenhaga, Tatum, Balam and Scarfe respectively. It has also, at the suggestion of its discoverer David Balam, named asteroid (4789) Sprattia in honour of Christopher Spratt, a well-known amateur astronomer and member of the University's gardening staff. The stellar models developed by Don VandenBerg, and his studies of stellar structure and evolution, are recognized as being among the best in the world; he received the B.C. Science Gold Medal in 1987. In recognition of the strengths of the research and undergraduate programs in astronomy, the name of the department was formally changed in 1987 to "The Department of Physics and Astronomy." A very recent development has been the establishment within the department of the editorial office of Publications of the Astronomical Society of the Pacific. The new editors of the Journal of this 122-year old society are Anne Cowley (PhD, Michigan), a professor of Astronomy at Arizona State University, and David Hartwick. An indication of the stature of work done in the Department is provided by a Globe and Mail article (October 27,1995) which refers to an independent study of citations in Canadian research. Our astronomy group ranked number one in Canada in terms of citations per refereed paper, and number three in terms of total number of citations (remarkable considering the very small size of the astronomy group). The astronomy group was the only group or department at the University of Victoria to receive mention in the Globe and Mail article. Also, Ann Gower was cited in the recent Maclean's university issue for excellence in teaching at UVic. LA PHYSIQUE AU CANADA juillet à août, 1998 215 FEATURE A R T I C L E ( A HISTORY O F T H E DEPARTMENT. ..) AWARDS, A D M I N I S T R A T I O N , A N D THE FUTURE Two of our faculty (Alan Astbury and Chris Garrett) are Fellows of the Royal Society (London), as are two of our adjunct faculty (Werner Israel and Sidney van den Bergh). Astbury, Garrett, Israel, van den Bergh, and adjunct professor Roy H y n d m a n are also Fellows of the Royal Society of Canada. Three of our faculty members have held NSERC E.W.R. Steacie Memorial Fellowships (C.J.R.Garrett, F.D.A.Hartwick, and D.A.Vandenberg). Garrett has also held a Guggenheim Fellowship, and Vandenberg is currently on a two year Killam Award. In 1990 John Dewey was awarded the Ernst Mach Gold Medal of the German Fraunhofer Gesellschaft for his contributions to the understanding of shock wave reflection phenomena. Our faculty collaborate with other researchers at many centres in Canada and abroad which are renowned for their outstanding research; and many of our faculty have served on NSERC Grant Selection and other important advisory committees. A number of our faculty have been active in administrative positions within the university; most notably, Howard Petch, w h o served as President of the University from 1975 until 1990. Also, however, John Climenhaga was Dean of the Faculty of Arts and Science from 1969 to 1972; and John Weaver has been Dean from 1993 to 1998, first of the Faculty of Arts and Science and then, w h e n the Faculty had been split (after his own initiative), of the Faculty of Science. John Dewey served the university in administrative positions for many years, first as Dean of Academic Affairs, and then as Dean of Graduate Studies, and Associate Vice-President Research. In 1985 and 1986, he was seconded to the Provincial Government as Deputy Minister of Universities, Science and Communication. The Department is now well established on the Canadian scene, with very substantial research strengths in astronomy and sub-atomic physics, and with both graduate and a variety of co-op and regular undergraduate programs. It is possible that further joint appointments with SEOS may be made in the areas of ocean and atmospheric physics. However, the department is also seeking to establish a new area of strength, possibly quantum optics; and has been exploring possibilities in the area of medical physics, largely through the efforts of Lyle Robertson. The department has hosted numerous conferences in Physics, Astronomy, and Geophysics over the years; but, notably the 1983 CAP Congress, held jointly with a meeting of the Canadian Astronomical Society; and the 1982 and 1991 Canadian Undergraduate Physics Conferences. It plans to host the CAP Congress in June 2001, and all Canadian physicists are invited to come at that time, in part to enjoy beautiful sunny Victoria. ACKNOWLEDGEMENTS The authors are grateful for comments and suggestions received from many members of the department. Further information about Ihe current activities of the department and its members can be obtained from the department web-site, http://www.phys.uvic.ca. INVITATION The Editorial Board welcomes articles from readers suitable for, and understandable to, any practising or student physicist. Review papers and contributions of general interest are particularly welcome. 216 PHYSICS IN CANADA J u l y / A u g u s t 1998 Le comité de rédaction invite les lecteurs à soumettre des articles qui interessaient et seraient compris par tout physicien, ou physicienne, et étudiant ou étudiante en physique. Les articles de synthèse et d'intérêt général sont en particulier bienvenus. A R T I C L E DE F O N D ( S I L I C O N M I C R O T I P S . . . ) A SILICON MICROTIPS FIELD-EMISSION DISPLAY PROTOTYPE by C. Py, P. Grant and M. Gao shortcomings of this device are used as the basis for discussion for which direction should be taken to ield-Emission Displays are flat-panel displays bring this prototype closer to a viable product. that retain the intrinsic visual properties of CRTs. For this reason, they are trying to enter PRINCIPLE OF OPERATION the market through applications where the limitations of liquid crystal displays are unacceptable Images in a FED are obtained (see Figure 1), like in a In the long term, FEDs are expected to also become Cathode Ray Tube, by bombarding a phosphor screen cheaper and more power-efficient, though the with an electron beam. technology is now facing However, in a FED each pixel problems such as phosphor of the screen receives A Field-Emission Display prototype lifetime and efficiency as well electrons produced by microas the high cost of drivers. based on arrays of silicon microtips emitters integrated on a plate has been fabricated in NRC; the and directly facing the pixel, The first part of this paper whereas in a CRT the beam of characteristics of the device are deals with the principle of a single electron gun is rasused as the basis of a discussion operation of FEDs. Then, the tered through all the screen fabrication process flow is on what steps are taken to make it pixel by pixel. Micro-emitters detailed and the results a viable product. are addressed by an XY maobtained are presented. The trix and there is no need for performance and deflection optics. The plate on which the emitters are integrated is usually referred to as the cathode, and the screen as the anode. F Anode CRT Rastering optics Electron gun Emitters Column addressing Fig. 1 | Field-Emission Display principle of operation compared to a Cathode Ray Tube. In a CRT the beam of a single electron gun illuminates the anode pixel by pixel. In a FED micro-emitters are integrated on a plate facing the anode and illuminate the pixel they face when addressed by an XY matrix. The micro-emitters are microtips surrounded by an extraction gate lying on a thick insulator (Figure 2). When biased at a voltage higher than that of the microtip, the extraction gate produces a very intense field at the apex of the microtip to thin down the Fermi barrier (from the emitter material to vacuum) and permit electrons to tunnel through it. Electrons are then accelerated towards the anode. To form the XY matrix, microtips are grouped in columns and the extraction gate is etched in rows. The display is addressed row by row, which means that all the pixels of a same row can be illuminated at the same time. Assuming that microtips emit for a gate to microtip voltage of 80V, the active row is biased at +50V and pixels will be illuminated at the intersection of that row and columns biased at -30V. Drs. Py, Grant and Gao work at the Institute for Microstructural Sciences of the National Research Council of Canada, in Ottawa Ontario LA PHYSIQUE AU CANADA juillet à août, 1998 217 FEATURE ARTICLE (SILICON MICROTIPS...) Boron Diffusion n Dot lithography Silicon etch Thermal Oxidation Extraction gate Evaporation Fig. 2 Micro-emitters in a FED are c o m p o s e d of a microtip a n d an extraction gate lying on a thick insulator. 1/um emitters will typically emit current w h e n the extraction gate to microtip voltage is about 80V. Pixels are illuminated at the intersection of the active row, biased at +50V and active columns, biased at -30V. SiO, lift-off Column vias WARN M • < -•'V-K.' Microtips are usually made of an evaporated metal'11 or etched from silicon'21, though some other materials like GaAs are being evaluated for other applications' 3 '. IMS chose silicon because the compatibility of the fabrication process with traditional Integrated Circuit processes offers at least two significant advantages: being able to use existing IC production lines, and thus limit capital investment; - being able to integrate addressing electronics on the same plate as the emitters. This would solve the problem of connecting the matrix to discrete drivers, which can be a limiting factor in the small and high resolution display market that FEDs are targeting. PROCESS FLOW In the past two years, IMS developed a fabrication process for a proof-of-concept prototype cathode based on silicon microtips. As seen in Figure 3, the conical aspect of the microtip is obtained by undercutting silicon under a Si0 2 round dot mask. In order to obtain a microtip with a high aspect ratio, Reactive Ion Etching is preferred to wet etching. Increasing the aspect ratio of microtips enables extracting electrons for a lower gate voltage while reducing the capacitive coupling and chances of breakdown between the base of the microtips and the gate. The RIE is stopped before the dot falls off and 218 P H Y S I C S IN CANADA July/August 1998 Fig.3 Bonding pa< pads M ™ Matrix Connections pads IMS's silicon microtip fabrication process. The microtip is obtained by under-cutting silicon u n d e r a S i 0 2 dot m a s k and consuming the rest of the silicon by thermal oxidation. The dot is kept as a self-aligned mask to deposit the thick insulator and the extraction gate; it is then etched-off. C o l u m n s are obtained by thermal diffusion of p type impurities in a n type substrate. the remaining silicon is consumed by thermal oxidation. This layer provides good electrical insulation between the base of the microtip and the extraction gate. It also permits keeping the dot as a self-aligned mask to evaporate the thick insulator and the extraction gate without compromising the microtip sharpness. After these evaporation steps, the dot is etched-off and the emitter is complete. The Scanning Electron Microscope picture of F;igure 4 shows a group of microtips. The initial dot diameter was l/^m, and the resulting gate aperture is approximately 1.2yum. The radius of curvature at the apex of microtips is estimated between 5 and lOnm, which provides a high field enhancement factor. The integration of emitters in a XY matrix requires etching the extraction gate in rows (not shown in Figure 3) and separating the base of the microtips in columns. Electrical insulation from the n type substrate is achieved by doping columns with p type impurities A R T I C L E DE F O N D (SILICON MICROTIPS...) (Boron). The substrate is grounded so when a column is active (negatively biased) the p-n junction is reverse- biased and therefore insulating. The junction has to sustain a high reverse voltage (at least -30V) and be several microns deep (microtips are etched in the columns). The columns are obtained in a one step thermal diffusion using thermal oxide as a mask. After forming the emitters, contacts to the columns are made by etching holes through the two oxide layers and forming nickel silicide contacts. Finally, Au connection pads are deposited for rows and columns contacts, and the device is attached in a package as shown in Figure 5. The prototype, shown in Figure 5, is an array of 10 rows by 10 columns with a very coarse 2.54mm pitch allowing a simple connection and addressing scheme. From a micro-fabrication point of view, obviously, a much smaller pitch could be attained. The anode is a glass sheet covered with indium tin oxide, a transparent conductive material, and coated with a ZnO:Zn phosphor powder. ZnO:Zn is known to be a very efficient phosphor at low voltages and is used in vacuum fluorescent displays (used for example in microwave ovens and car stereos). Unfortunately, its very broad spectrum (whitish green) makes it useless for colour displays. The phosphor is synthesized in-house by reducing a ZnO powder in an hydrogen atmosphere, and deposited by sedimentation from a solvent. Anode and cathode are mounted together 1mm apart in a vacuum chamber. The rows and columns of the cathode, the substrate and the anode are connected to addressing electronics controlled by a computer. OBSERVATIONS A N D RESULTS Typical emission characteristics are shown in Figure 6. The anode current is plotted as a function of the gate to microtip voltage for several rows of the same prototype. The anode voltage is found to have very little influence on emission as long as it stays higher than the gate voltage; it was kept at 500V. A current of 1mA can be obtained at a gate to microtip voltage of 53V from a 0.2cm2 emissive area containing about 200,000 emitters. This voltage value is relatively low compared to earlier reports' 2,4) . The corresponding 5 m A / c m 2 current density meets the requirements of commercial FEDs. Figure 7 is an anode-side view of the prototype in operation where rows are horizontal and columns vertical. Rows 2,4,5,6 and 8 are working. The other five rows are in short-circuit with the substrate. Deposition of the thick insulator out of a clean-room is probably responsible for a high particle count. Within working rows, some pixels emit far less than others, because emitters were not properly shaped in those places. This is the main reason why rows 5 and 6 have a higher turn-on voltage than rows 4 and 8. Because of their high aspect ratio, the height of YSIQUE AU CANADA juillet à août, 1998 219 F E A T U R E A R T I C L E (SILICON M I C R O T I P S . . . ) /8 12001000- / 800- 3 600- 1-1 400- 4 P 6 2000-1— 25 • • — 30 «? 35 ^ 40 45 50 55 1 60 Vgt(V) Fig. 6 Anode current la as a function of the extraction gate to microtip voltage Vgt for several rows of the cathode. The anode voltage is 500V. microtips is strongly dependent on the initial diameter of the dot. Statistical analysis of dot diameters shows a 6% variation within a sample, which translates into a 500nm height variation and a factor of 10 in emission for identically sharp microtips. The dot lithography is m a d e with a contact aligner, so the precision of the patterning depends on how good the contact between the mask and the sample is and how smoothly the photoresist has been spin-coated. Obviously these steps must be improved to obtain an homogeneous illumination of the screen. Structures, observed within certain pixels, are partly due to flickering of the emission. Variations in the emitted current reflect interactions (adsorption-desorption and flip-flop) of the apex of microtips with atoms of the remaining gas'51. Halos are also observed around the pixels: due to the phosphor low transparency (3%), most of the emitted light is trapped between the two plates. A more sophisticated deposition method would produce much thinner phosphors. However, more than 50% of the light would still be emitted toward the cathode, not the viewer. In CRTs, this problem is addressed by coating the cathode side of the phosphor with a thin A1 mirror layer through which electrons penetrate. This requires that electrons be accelerated to at least 5kV 6 , which is difficult to obtain in FEDs due to a limitation in the cathode to anode distance. 220 PHYSICS IN CANADA J u l y / A u g u s t 1998 Fig. 7 Anode-side view of the operating device. Rows are horizontal, row 1 is on top. DISCUSSION The fabrication process developed at IMS enables reproducibly obtaining field-effect emission from microtips with a current density satisfactory for display applications. This process also successfully integrates the fabrication of an XY matrix to allow the formation of images. However, certain shortcomings are observed: — Short circuits between the substrate and extraction gate rows, - Short-circuits between microtips and extraction gate, - Emissivity discrepancy between microtips (many microtips don't emit at all !), and - Variation with time in microtip emission (flicker). Two other areas have been identified where improvement must be seen to enhance the performances of FEDs and decrease their price: - High switching voltage' 7 ': the base of the microtips and the extraction gate form a large capacitance that loads the drivers when switching voltages. As seen in Figure 6, the voltage that must be switched from the 'off' to the 'on' state is not as high as the turn-on voltage. Still, no less than 25V has to be switched on rows and columns. Drivers for these high voltages are expensive, and the reactive power lost in the matrix goes as the square of the switched voltage. Lowering the switched voltage is thus very beneficial. Low phosphors luminance: even though emission from a microtip is directive, the beam aperture is still an estimated 15 to 30° solid angle. For a given pixel resolution, this aperture limits the cathode to anode distance. Thus the anode voltage A R T I C L E DE F O N D (SILICON MICROTIPS...) is limited to a value far lower than in a CRT (typically several hundred volts compared to 30kV), which dramatically lowers the anode luminance. The fact that FEDs are addressed row by row and not pixel by pixel increases the illumination time by the number of columns (640 in a VGA screen), but the current density still must be increased drastically. This change in the nature of the beam illuminating the anode has led to research in the synthesis of n e w families of phosphors181, but their luminous efficiency and lifetime at high current densities are not yet satisfactory. the aperture of the beam emitted by microtips, allowing an increase in the anode voltage. In some designs, a focusing electrode is added on a separate plate between the cathode and the anode, which results in a very complicated mechanical setup. Integrating a focusing electrode on the cathode1101 is a more elegant solution that IMS is exploring. We have proved by simulations' 11 ' that this focusing electrode can also be used to increase the current density received by the anode without increasing that of the cathode, and multiply the luminance of FEDs by a factor 2.5. Some of the defects observed in IMS's prototypes, especially short-circuits between the substrate and extraction gate rows and microtip emissivity discrepancy, would be much less dramatic in an industrial environment. Still, the fabrication process has to reconcile a very low acceptance level for visual defects (a few black pixels at best, and a few percent variation in luminance) with the difficulty of obtaining a zero-defect cathode on a large surface. This goal can be attained only if the cathode design is redundant and defect-tolerant. Redundancy is mainly achieved by having a large number of microtips per pixel. Tolerance to short-circuits and emissivity discrepancy requires controlling emitted current pixel by pixel, when drivers can only control it column by column. One solution is to incorporate a resistive layer between the columns and the microtips that equalizes the current (by decreasing that of most emissive microtips) and sustains short- circuits1"1. However, w e believe that an active control of the current will provide superior results, and that the addressing electronics will eventually have to be integrated on the same substrate as the emitters for small and high resolution display applications. CONCLUSION In parallel, IMS is working in two different directions to address the other shortcomings cited above: - Diamond-Like Carbon coatings on microtips: DLC is known to be a very inert material that is expected to have less interaction with residual gases than silicon. Being a very hard material, it is also difficult to etch into microtips, but coating a thin layer on silicon microtips should increase emission stability and emitters lifetime. Moreover, DLC has a lower work function than silicon, and w e estimate that it brings a reduction of the switching voltage by a factor of 219'. - Simultaneous focusing and deflection: a natural way to enhance the luminance of FEDs is to reduce A Field-Emission display prototype fabrication process has been successfully developed at IMS, giving very encouraging results. The shortcomings of the prototype have enabled to clearly identify axes of further development needed to make the technology viable. ACKNOWLEDGEMENTS The authors wish to thank their colleagues: M. Buchanan and S. Das for counseling, C. Adams, L. Berndt (from Carleton University, Ottawa), H. Tran, G. Laframboise and P. Marshall for their participation at different stages of the fabrication process and J. Fraser, S. Laframboise and S. Rolfe for their help in characterizing the prototype. REFERENCES I . C.A. Spindt, j.Appl.Phys, vol 39 (1968) p3504 2. K. Betsui, Tech. Digest of the 4th IVMC, N a g a h a m a , Japan, Sept 6-9,1991, p l 3 7 3. J.L. Shaw et al, Le Vide, Les Couches Minces, Supplt n.271 (1994) p i 24 4. R. Meyer, Tech. Digest of the 4th IVMC, N a g a h a m a , Japan, 6-9 Sept 1991 p l 4 1 5. C. Py & R. Baptist, ]. of Vac. Sci. & Technol. B 12(2), (1994), p685 6. J. Browning et al, Tech. Digest of the 17th IDRC, Toronto, C a n a d a , Sept. 15-19,1997, pF-42 7. R.T. Smith, Tech. Digest of the 17th IDRC, Toronto, C a n a d a , Sept. 15-19,1997, pF-35 8. C.J. S u m m e r s , Tech. Digest of the 10th IVMC, Kyongju, Korea, Aug. 17-21,1997, p244 9. J. Dobrowolski et al, Physics in Canada, 54(5) (1996) p207 10. Y. Yamaoka et al, Tech. Digest of the 9th MPC, Kitakyushu, Japan, July 8-111996 11. C. Py & P. Grant, Tech. Digest of the 17th IDRC, Toronto, C a n a d a , Sept 15-19,1997, p327 LA PHYSIQUE AU CANADA juillet à août, 1998 221 FEATURE ARTICLE ( C O H E R E N T G E N E R A T I O N . ..) COHERENT GENERATION A N D CONTROL O F PHOTOCURRENTS IN G A A S USING THREE COLOUR BEAMS by J.M. Fraser, A. Haché, and H.M. van Driel Young's double slit experiment. The light pattern he coherent generation a n d phase control of falling on a screen placed behind two illuminated slits photocurrents via q u a n t u m interference of depends not only on the individual intensities but on optical absorption processes represent a novel the relative phase of the beams incident on the screen. noncontact method for If out of phase, the two fields current generation in bulk can perfectly cancel leaving a semiconductors. Recently dark region. Similarly within By exploiting quantum interference such an effect w a s our q u a n t u m mechanical in optical absorption pathways, demonstrated in GaAs at system, the total transition rate carriers can be excited with a polar room temperature using of a physical process depends distribution in momentum space beams of frequency <o and on both the magnitudes and 2oo[1]. We have extended phases of the individual this physical process to its pathway amplitudes. For a system with two possible pathways linking the same more general form using three b e a m s of wavelengths initial and final states, the total transition rate is: 1.44 jim, 1.80 (im, and 0.80 urn. For pulse durations of 200 fs and 250 k H z repetition rate, w e produce easily rate a | A + B| 2 =|A| 2 +|B| 2 +2|A||B|COS(<|>a -<t>B) measurable current with 0.80 nm beam average where A and B correspond to the individual transition powers as low as 40 nW. W e verify that the current amplitudes. The introduction of the pathway magnitude exhibits a linear d e p e n d e n c e on individual optical field a m p l i t u d e (0.80 urn). corresponding to B can increase the transition rate of the physical process or completely turn it off COHERENT GENERATION A N D CONTROL depending on the value of <j>A - <}>B . 'Coherent control' is the manipulation of this relative phase to Creating and controlling currents in semiconductors is control the outcome of a transition. of p a r a m o u n t importance in m o d e r n technology. Methods involving Drude-type motion of carriers Coherent control has been used primarily in low caused by an externally imposed bias are dominant density gas systems d u e to the relatively long but in certain applications suffer f r o m limitations, dephasing times of the induced polarizations,. such as limited response time. By exploiting q u a n t u m Researchers have been able to manipulate interference in optical absorption pathways, carriers multiphoton ionization rates' 3,4,5 ' and photoelectron can be excited with a polar distribution in m o m e n t u m angular distributions' 6 '. Extending coherent control to 2 space' '. This is electrical current but of a different kind. The carriers do not require an external field to J.M. Fraser, a graduate student in the Physics Dept. be accelerated but are created with non-zero average at the Univ. of Toronto, is one of three Lu monies m o m e n t u m . This process offers a n e w w i n d o w of Best Student Paper winners at the 1998 CAP research into ultrafast current generation and decay Congress. Prof. H.M. van Driel is his supervisor. on the subpicosecond timescale. Prof. A. Haché works at l'Université de Moncton. T Q u a n t u m interference between t w o or more pathways linking the same initial and final state is not a novel concept in itself. A classical analogy is provided by 222 PHYSICS IN CANADA J u l y / A u g u s t 1998 ARTICLE D E F O N D semiconductors is not simple. Carriers in solids have dephasing times on the order of 100 fs or less. Dupont et. al.'71 succeeded in controlling the direction of motion of optically excited electrons in a AlGaAs/GaAs q u a n t u m well structure. Recently, coherent control of current using normal band-toband transitions in a bulk semiconductor was observed' 11 . Coherent control of current is a physical process inherent to the bulk semiconductor. The excitation pathways used to demonstrate this effect were oneand two-photon absorption, provided by two phaselocked beams at frequency to and 2to. The resulting current injection rate is given by' 2 ': cos cosf (01 Fig-1 Conduction and valence band linked by oneand two-photon absorption provided by signal, idler a n d s u m - f r e q u e n c y beams For G)s = «i, we return to the co/2to process described above and y ijld simplifies to r| l j k l . J ; = T l y j E j ( - 0 3 ) E k ( - © ) E , (2co) sin(2<t) œ - f 2 o ). where "H ,j kl is dependent on sample type and frequency co. The relative phase between the two beams determines the current amplitude and direction. Current generated by this term persists until scattering events randomize the direction of carrier motion. This has been proposed to occur within 100 fs. This is an incredibly rapid process compared to standard Drude-type currents which persist until the carriers are removed from the device or undergo recombination (typically on the order of 100s of picoseconds or longer). Bandwidths of devices using biased currents, such as photodetectors, are limited by this time scale. Coherently controlled currents provide intriguing possibilities for applications that require extremely fast response times. We now propose that the above expression is a specific case of a more general process. The pathways can be provided by any exciting optical fields that link the same initial and final states. Specifically, two beams of different frequencies along with a third beam whose frequency is the sum of the first two can yield phase-controlled currents (figure 1). The current injection term for this more general process is: J | = Y ijkiIEj ( - © s ) E k (-co j) E, (ca s f ) sin(<}>s + 4>i - <t>sf )• where, using standard terminology, tos is the frequency of the signal beam, toj is the frequency of the idler, and tosf is their sum-frequency (tos + o^). (COHERENT GENERATION...) Coherently controlled current injection should occur for light fields of any intensity, but it is preferable to use high intensity ultrashort light pulses due to its nonlinear dependence on electric field amplitude. 200 fs signal and idler pulses are generated by an optical parametric amplifier, p u m p e d by a regenerative amplified ti:sapphire oscillator at a repetition rate of 250 kHz. The two beams, at wavelengths 1.44 jim and 1.80 nm, have average powers of l-2mW. Though these pulses have high peak intensities, the low average powers minimize thermal effects, such as sample damage. A phase-locked beam of 0.80 nm is produced by sum-frequency generation between the signal and idler in a 1.5mm KTiP0 4 (KTP) crystal (type II phase matching: o+e~o). Maximum average power for the sum-frequency beam is 40 (iW. The three colours are separated into independent delay lines (figure 2) to allow individual control of pulse delay to maximize temporal overlap. One delay line (0.80 |am) is mounted on a piezo-electric actuator to allow fine control of the relative phase (A(j>). The three beams are focused onto the sample with beam waists ranging from 60|im to 90(im, yielding maximum peak irradiances of 1 GW/cm 2 , 0.6 G W / c m 2 , and 20 M W / c m 2 f o r signal, idler and sumfrequency respectively. The ultrafast pulses produce currents that last only on the order of subpicoseconds. To detect these brief signals, we integrate the current by collecting charges on metallic electrodes. We leave LA PHYSIQUE AU CANADA juillet à août, 1998 223 FEATURE ARTICLE ( C O H E R E N T G E N E R A T I O N . ..) 80 Hz sinusoidal motion Optical parametric amplifier rep. rate: 250 kHz pulsewidth: 200 fs As =1,44 p m Ai =1.80 j i m average power: 1-2mW Au mirror lock-in amplifier (80 Hz) 100 MQ termination Fig. 2 o Signal amplitude (mV) 0.4 Experimental set-up. For the purpose of clarity, focusing optics are omitted and overlapped beams are shown spatially separated. Beams reflected off gold mirrors are directed slightly downward to be intercepted by a pick-off mirror and sent to the sample. RG780 and RG1000 indicate optical filters. ^WA -0.4 J Fig. 3 r Relative phase (A<J>) Collected charge amplitude as a function of relative phase between three colour beams of 1.44um, 1.80um and 0.80um. Solid line shows the expected phase dependence. this planar metal-semiconductor-metal device unbiased throughout the experiment. The semiconductor is a 1 jxm epilayer of annealed, lowtemperature-grown GaAs sitting on a substrate of normal GaAs (001 orientation). The gold electrodes are separated by a 10 urn gap. The fast trapping time of the LT-GaAs causes the sample to return to high resistivity on a picosecond time scale thus minimizing 224 Au mirror PHYSICS IN CANADA July/August 1 9 9 8 carrier discharge through the sample. The electrodes are connected directly to a lock-in amplifier (100 MQ input impedance). The measured signal corresponds to the integrated current, i.e. total collected charge, discharging through the lock-in amplifier. Its amplitude is sensitive not only to the amount of current created but to the time-dependent resistivity and capacitance of the sample and measuring circuit. Background free measurement is done by varying the relative phase sinusoidally over Acj) = TC rad at 80 Hz and using lock-in amplification. The relative phase offset is varied over two periods (figure 3) showing the expected phase dependence determined experimentally by a separate nonlinear process. The signal reduces to noise if any one of the three beams is blocked. For polarizations that would produce no current for the o)/2oo process (y x x y x ) the effect also disappears' 21 . Varying the sum-frequency power while maintaining both the signal and idler average power constant (figure 4) shows that current depends on I(o>sf)047, close to expected value of 0.5. Note that the current level is still easily detectable even with the 0.80 urn average beam power as low as 40 nW. All experiments are all done at room temperature with minimal lock-in amplifier averaging. These ARTICLE D E F O N D 10 E. COPYRIGHT NOTICE 1 TO A U T H O R S A N D READERS OF "S c g> '</> O 6 IN 0.1 0.01 Copyright of original articles published in Physics in Canada remain with the author and authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients is granted by the Canadian Association of Physicists. 0.1 1 10 100 0.80|im average pow er (j.iW) Dependence of collected current on SF average power. Solid line is the best fit of the equation y=ax" with n=0.47. Expected exponent is 0.5. results indicate that three colour beams can generate current. Manipulation of the relative phase between the beams provides control of its amplitude and direction. Theoretical analysis of the m a g n i t u d e of this effect requires further development. Spectroscopic studies, in both theory and experiment may yield interesting results, particularly as one frequency approaches zero. Extensions to other semiconductors and timescales (e.g. ns optical pulses) will also be pursued. The above permission does not extend to other kinds of copying, such as copying for general distribution, or advertising or promotional purposes, for creating new collective works, or for resale. For such copying, arrangements must be m a d e with the publisher. For convenience, an offprint price list is published in this issue of Physics in Canada. AVIS A U X A U T E U R S ET L E C T E U R S DE LA PHYSIQUE AU CANADA SUR LES DROITS DE REPRODUCTION ACKNOWLEDGEMENT The authors gratefully acknowledge financial assistance from the Natural Sciences and Engineering Research Council of Canada a n d Photonics Research Ontario. REFERENCES A. Haché, Y. Kostoulas, R. Atanasov, J.L.P. H u g h e s , J.E. Sipe, and H.M. van Driel, Phys. Rev. Lett. 78, 306 (1997). R. Atanasov , A. Haché, J.L.P. H u g h e s , H.M. v a n Driel, and J.E. Sipe, Phys. Rev. Lett. 76,1703 (1996). 3. E.A. Manykin a n d A.M. A f a n a s ' e v , Sov. Phys. JETP 25, 828 (1967). D.J. Jackson a n d J.J. W y n n e , Phys. Rev. Lett. 49, 543 (1982). C. C h e n , Y-Y. Yin, a n d D.S. Elliott, Phys. Rev. Lett. 64, 507 (1990). Y-Y. Yin, C. C h e n , D.S. Elliott, a n d A.V. Smith, Phys. Rev. Lett. 69, 2353 (1992). E. D u p o n t , P.B. C o r k u m , H.C. Liu, M. Buchanan, a n d Z.R. Wasilewski, P h y s Rev. Lett. 74, 3596 (1995). 1. PHYSICS CANADA - 0.01 Fig. 4 ( C O H E R E N T GENERATION...) Les auteurs conservent les droits de reproduction des articles originaux publiés dans La Physique au Canada et l'Association canadienne des physiciens et physiciennes octroie l'autorisation de photocopier les items destinés à un usage interne ou personnel, ou à un usage interne ou personnel de clients particuliers. La présente permission ne s'applique pas à d'autres genres de reproduction, notamment la reproduction en vue d ' u n e distribution générale, à des fins publicitaires ou promotionnelles, pour la création de nouveaux travaux collectifs, ou pour la revente. Dans ce cas, il faut prendre les dispositions qui s'imposent en communiquant avec l'éditeur. LA PHYSIQUE AU CANADA juillet à août, 1998 225 FEATURE A R T I C L E ( C O E F F I C I E N T DE DIFFUSION ...) COEFFICIENT DE DIFFUSION EXACT POUR DES SYSTÈMES AVEC DES CONDITIONS AUX FRONTIÈRES PÉRIODIQUES by Jean-François Mercier relation de Nernst-Einstein: P lusieurs problèmes biologiques, chimiques et physiques peuvent être réduits à la diffusion D — = lim ^i(e)* lim (1) D, e-0 e-0 aléatoire de particules sur un réseau ponctué d'obstacles fixes et impénétrables. Parmi les exemples on compte la diffusion de protéines dans le plan d'une membrane biologique, la diffusion de particules D0 et n0 étant respectivement le coefficient de colloidales dans une solution diffusion et la mobilité pour de polymères et la migration une particule libre (évoluant Plusieurs problèmes biologiques, d'un analyte dans un gel sur un réseau sans obstacles). chimiques et physiques peuvent d'électrophorèse. La méthode couramment utilisée pour être réduits à la diffusion aléatoire Numériquement, le calcul de étudier ce type de problèmes la mobilité relative n* s'avère de particule(s) sur un réseau est la simulation Monte-Carlo beaucoup plus facile que celui ponctué d'obstacles fixes et (SMC) sur u n réseau de taille du coefficient de diffusion impénétrables. finie avec des conditions aux relatif D*. Pour obtenir le frontières périodiques. Cette coefficient de diffusion d'une particule, il suffit donc de calculer sa mobilité dans la approche, extrêmement simple, permet de suivre la limite où e - 0 . diffusion de millions de particules et d'en déduire le coefficient de diffusion (R2 = 2dDt, où R est le déplacement de la particule, d la dimension de LA MARCHE ALÉATOIRE SUR UN RÉSEAU l'espace et t le temps). Dans le modèle de la marche aléatoire sur un réseau, Récemment, nous avons développé une technique la migration de particules, attribuable au mouvement permettant de calculer, pour une distribution Brownien, s'effectue par des sauts discrets de d'obstacles donnée, le coefficient de diffusion D d ' u n e grandeur L=1 (le pas du réseau) et de durée T = particule de façon exacte. Cette technique de calcul est L 2 /2D 0 = 1 (en unités normalisées). Sur un réseau plus rapide que les SMC et peut facilement être carré sans obstacle, pour chaque intervalle de temps t, adaptée à tout type de réseau (carré, triangulaire,...) une particule possède une probabilité p = VA de migrer de dimension d^2. Après avoir décrit la méthode, sur un des quatre sites adjacents à son site de départ. nous donnerons des exemples de distributions Si le système comporte des obstacles, un mouvement d'obstacles périodiques, aléatoires et fractales. conduisant une particule sur le site occupé par un obstacle est rejeté et la particule reste sur son site de THÉORIE départ. Si un champ uniforme, pointant dans la position positive des x, est appliqué, les probabilités LA RELATION NERNST-EINSTEIN pour une particule de migrer sur les quatre sites qui Quand un champ externe e est appliqué sur une particule, on définit la mobilité dans la direction du champ par: n = v / e , où v est la vitesse moyenne de la particule. Lorsque e - 0 , le coefficient de diffusion D de la particule est directement relié à sa mobilité par la 226 PHYSICS IN CANADA July/August 1998 Jean-François Mercier, u n étudiant au deuxième cycle à l'Université d ' O t t a w a , est u n des trois gagnants d u prix Lumonics p e n d a n t le Congrès de l'ACP 1998. ARTICLE DE F O N D (COEFFICIENT DE DIFFUSION ...) lui sont adjacents ne sont plus identiques. On parle alors de marche aléatoire biaisée. Un champ dans la direction des x n'affecte pas les probabilités de saut dans la direction y, qui resteront p±y = 1/4. Les probabilités que le prochain saut soit dans la direction du champ (+) ou dans la direction opposée (-) sont données par: 1/2 I X 1 + e l 2 e l±e résultats directement. Pour les plus gros systèmes, des simplifications algébriques permettent de simplifier énormément le problème en éliminant la dépendance explicite au paramètre indéfini e. La première étape est de séparer les éléments en un terme purement numérique (indice I) et un dépendant de e (indice e). L'équation A | p)= | b) implique alors: A J p . H V et Aj | pe) = -A £ | pj) (3 ) (2) Puisque le champ tend vers zéro, seuls les termes du premier ordre en e sont conservés. Il est important de noter que le temps moyen entre chaque saut t n'est pas affecté, au premier ordre, par e. LA M É T H O D E N U M É R I Q U E La vitesse moyenne d'une particule évoluant sur un réseau peut être obtenue en sommant les produits de la probabilité de présence de la particule sur chacun des sites et de la vitesse de la particule sur ces sites. La mobilité est ensuite obtenue en divisant cette vitesse moyenne par l'intensité du champ, et le coefficient de diffusion en faisant tendre e vers zéro. La vitesse locale sur chacun des sites est simplement V; = p+xL+-p.xL., où L± =1 s'il n'y a pas d'obstacle dans la direction donnée et 0 dans le cas contraire. Avec un champ externe, les probabilités de présence sur les sites ne sont plus uniformes. À l'état stationnaire, la probabilité pour la particule de se trouver sur un site i est indépendante du temps. Les probabilités de se trouver sur chacun des sites sont couplées et il est possible d'obtenir, pour chacun des sites, une équation pilote reliant la probabilité d'être sur un site i à celles d'être sur les sites adjacents. Avec la condition de normalisation (£p, = 1), les probabilités sont reliées par un système d'équations linéaires qui peut être résolu exactement. Le problème peut donc être réduit à la solution d'un système d'équations linéaires, représenté par A | p)= | b), où A, la matrice de transition, et | p), le vecteur probabilité, dépendent d u paramètre indéfini e. Pour de très petits systèmes il est possible d'utiliser le calcul symbolique avec des logiciels scientifiques tels que Mathematica ou Maple, et ainsi obtenir les La première équation correspond au problème sans champ et mène à la solution triviale d'une probabilité uniforme pour tous les sites libres: | p,) = {1/Nlibre} où Nlibre est le nombre de sites libres du système. Le vecteur | p£) est donc le seul inconnu, et le système à solutionner A, | p e )=-A e | p,) est maintenant purement numérique et ne comporte aucun terme en e. Notons que le produit ( v j p , ) est toujours nul puisqu'il représente la vitesse moyenne en absence de champ. Le coefficient de diffusion est donc: n r D =lim ( v r IP} n (E) = l i m — — e-0 e-0 <v = eIPi>+ < v i'P^ (4) E où n 0 = l / 2 pour un réseau carré à deux dimensions. APPROCHE NUMÉRIQUE La taille de la matrice de transition A augmente très rapidement avec la taille du système car nous avons une équation pour chacun des site accessible sur le réseau. Pour des systèmes relativement petits, les méthodes courantes de solution d'équations linéaires tels la décomposition LU peuvent être utilisées. Cependant, pour de très gros systèmes, les erreurs d'arrondissement et les limitations de mémoire et de temps de calcul rendent ces méthodes inutilisables. Il est possible d'obtenir de meilleurs résultats en utilisant le fait que la matrice de transition A est extrêmement éparse (le nombre de termes non-nuls par ligne dans la matrice de transition ne peut excéder le nombre de voisins immédiats, typiquement 4 à 8 dépendant du type de réseau). Les matrices éparses ont fait l'objet d'études poussées et des algorithmes très performants ont été développés pour les LA PHYSIQUE AU CANADA juillet à août, 1 9 9 8 227 FEATURE ARTICLE (COEFFICIENT DE DIFFUSION ...) solutionner. Avec les techniques d e sauvegarde et de solution itérative suggérées par Numerical Recipies, respectivement la « row-indexed storage method » et la « biconjugate gradient m e t h o d », des matrices de dimension 250000x250000, correspondant à des systèmes d e 500*500 en deux dimensions et de 60x60x60 en trois dimensions, ont pu être solutionnées sur Pentium Pro d e 200MHz. RÉSULTATS Des résultats exacts pour les coefficients d e diffusion permettent d e vérifier des modèles théoriques et de cerner de subtils effets d e géométrie. Cette section expose quelques résultats obtenus avec notre nouvelle approche. DISTRIBUTIONS D'OBSTACLES PÉRIODIQUES ET ALÉATOIRES Le coefficient d e diffusion D pour un système d o n n é dépend d e la concentration d'obstacles C (la fraction du réseau occupée par des obstacles). En général, plus le nombre d'obstacles est élevé, plus u n e particule est ralentie. Si la concentration atteint u n seuil critique, appelé seul d e percolation, la migration sur de longues distances devient impossible et le coefficient de diffusion est alors nul. Pour les très faibles concentrations, la d é p e n d a n c e d u coefficient de diffusion par rapport à la concentration est identique pour tout type d e distribution (périodique, aléatoire...) pour des obstacles d e m ê m e forme. Pour u n e particule de dimension l x l diffusant sur u n réseau carré à deux dimensions avec des obstacles ponctuels distribués aléatoirement, N i e n w e n h u i z e n et al.111 ont montré que la dépendance du coefficient d e diffusion en fonction de la concentration pour u n réseau infini pouvait être exprimé par u n e expansion en série: ZT = = 1 - ( 7 t - l ) C - 0.8558C2 + 0 ( C 3 ) Les résultats exacts n o u s ont permis d e montrer que le premier terme était également valide pour u n e distribution d'obstacles périodique. En outre, pour ce dernier système, n o u s avons aussi pu déterminer le deuxième coefficient d e façon exacte: a 2 = %[(TÏ-1)2+1] = +2,7932... 228 PHYSICS IN CANADA July/August 1998 Pour des distributions d'obstacles périodiques, notre méthode permet de déterminer le coefficient de diffusion exact en une seule itération. La situation est très différente pour les distributions d'obstacle qui comportent des composantes aléatoires. Dans ces cas, le coefficient de diffusion correspond à une moyenne sur toutes les distributions possibles, dans la limite d ' u n système infini. Les coefficients de diffusion pour chacune des réalisations aléatoires peuvent être calculés exactement, mais des erreurs dues au moyennage et à la tailles fini du système apportent u n e incertitude. Notons que ces limitations sont aussi présentes pour les SMC, avec le désavantage supplémentaire d ' u n e erreur sur le coefficient de diffusion de chacune des réalisations. Les résultats obtenues pour u n e distribution aléatoire sont en excellent accord avec ceux de la réf. [1]. Afin de démontrer que notre méthode peut facilement être adaptée à tout type de réseau, nous avons étudié le cas d ' u n e distribution d'obstacles aléatoire pour quelques concentrations sur un réseau triangulaire. Le tableau ci-dessous regroupe nos résultats et les compare à ceux de Saxton 12 ', obtenus par une étude SMC. Concentration C D*(Notre méthode) D* (SMC) 0,1 0.81822(7) 0.819(1) 0,2 0.6279(2) 0.629(1) 0,3 0.4248(3) 0.425(1) 0,4 0.2076(4) 0.210(1) Les coefficients de diffusion obtenus avec les résultats exacts sont un à deux ordres de grandeur plus précis que ceux obtenus avec les SMC. OBSTACLES FRACTALS Comme exemple d'effet géométrique subtil que des résultats exacts permettent de comprendre, la dépendance du coefficient de diffusion en fonction de la taille de la particule a été étudiée pour des obstacles fractals. Pour des obstacles non fractals, les particules plus grosses, qui ont de plus grandes probabilités d'entrer en contact avec les obstacles, sont plus lentes que les plus petites. Pour des obstacles fractals, la situation est différente. Les grosses particules ont certes de plus fortes probabilités de rencontrer les obstacles, mais les plus petites ont quant à elles plus ARTICLE DE F O N D (COEFFICIENT DE DIFFUSION ...) de chance de se perdre dans les multiples baies et tunnels sans issues associés aux fractals. Certains auteurs prétendent que ces deux effets peuvent, dans certain cas, s'annuler et ainsi rendre le coefficient de diffusion indépendant de la taille de la particule121. trois types de baies présentes sur l'amas. Encore une fois, ce détail aurait été très difficile à obtenir en utilisant les SMC, puisque les petites variations auraient vraisemblablement été noyées dans le bruit statistique. Afin d'exploiter nos résultats exacts pour les distributions périodiques, nous avons choisi d'étudier le fractal déterministe montré à la figure cicontre. CONCLUSION •H'M" f* Outre la grosseur de la particule (les particules sont des carrés de côté M), la séparation minimale entre deux fractals Q joue un rôle déterminant dans le 1 processus de diffusion. La figure ci-contre montre le coefficient de diffusion en fonction de la séparation Q pour des particules de spacing Q tailles M = 1,2 et 5. Pour de très petites séparations Q les particules plus petites sont les plus rapides. Pour des séparations Q beaucoup plus grandes que la grosseur des particules, les particules plus grosses sont plus rapides que les plus petites. Notons que la différence entre les coefficients de diffusion est très petite et qu'elle aurait été très difficile à identifier avec une SMC. La figure ci-contre montre le coefficient ° de diffusion en | fonction de la Io grosseur de la g particule pour une | séparation Q=16. On particle size M remarque que le coefficient de diffusion y est presque constant pour les particules de taille inférieure à 6, confirmant les résultats obtenus par Saxton121. On remarque également une augmentation subite du coefficient de diffusion, pour les particules de taille 2, 5 et 14. Une analyse du fractal nous apprend qu'il s'agit de la taille caractérisant les Contrairement aux SMC, notre nouvelle approche ne peut donner d'information sur la dynamique de temps courts et se limite à la diffusion stationnaire. De plus, notre approche se limite au cas de particules isolées et ne peut pas étudier la migration de multiples particules interagissant entre elles. Cependant, pour les particules isolées, notre approche numérique permet de calculer le coefficient de diffusion de façon exacte. Ces résultats exacts peuvent être très utiles pour vérifier des modèles théoriques (e.g. des expressions analytiques pour D(C)) et pour cerner des effets géométriques subtils (e.g. effet de la taille de la particule pour des obstacles fractals). De plus elle peut facilement être adaptée à tout type de réseau de dimension supérieure à un (par exemple à un réseau triangulaire) et on pourrait y ajouter des interactions entre les obstacles et les particules. Notre nouvelle méthode ne peut pas remplacer complètement les SMC, mais dans la mesure où pour les particules isolées les résultats obtenus sont exacts et les temps de calcul sont avantageusement comparables à ceux des SMC, nous croyons qu'elle offre une alternative, ou, à tout le moins, un complément très puissant aux SMC. REMERCIEMENTS Ce travail a été effectué en collaboration avec Gary W. Slater et Hong L. Guo et est supporté par une bourse du fonds pour la formation de chercheurs et l'aide à la recherche (FCAR, Québec) à JFM et par une subvention du Conseil de recherches en sciences naturelles et en génie du Canada à GWS. RÉFÉRENCES 1. Ernst, M. H., Nieuwenhuizen, T.M, Van Velthoven, P. F. J., J. Phys. A 1987, 20: 5335-5350. 2. Saxton M. J., Biophys. ]. 1993, 64:1766-1780. LA PHYSIQUE AU CANADA juillet à août, 1998 229 FEATURE A R T I C L E (ATOMIC ORDERING...) ATOMIC ORDERING A N D SURFACE INSTABILITIES IN T H I N FILMS by François Léonard and Rashmi C. Desai Our recent' 9 ' non-equilibrium analysis of the joint stability/instability of atomic ordering and surf ace any III/V alloys spontaneously form deformations during the growth of thin films, ordered structures during thin film considers the essential and generic properties of these growth by deposition techniques' 1,21 . The understanding of the alloy thin films and should be fundamental processes applicable to a variety of leading to the formation of systems. It takes into account Recently, strong experimental these ordered structures the surface dynamical processes evidence has shown that the and the control of the as well as the thermodynamics direction of step motion at the resulting microstructure is of the epitaxial alloy layer, and surface determines which of two of prime importance for the can describe layers grown in design of modern devices. the ordered and disordered subvariants of the ordered The Cu-Pt type structure is regions of the phase diagram. structure is formed. by far the most commonly The evolution of the order observed structure, and is parameter is coupled to both the morphology of the free surface and the found to alter the electronic and optical properties of 2 composition in the film. We also take into account (i) the materials grown' '. Experimentally, only two of the constant deposition of material which tends to mix the four subvariants of the Cu-Pt structure are the surface atoms and favors disordering, (ii) the observed; the film microstructure consists of a mismatch between the substrate and the overlayer distribution of submicron-sized domains of the two and (iii) differences in the lattice constants of the alloy subvariants. elements. The current understanding of the spontaneous formation of the ordered structures is that the The model is applicable to systems where only two minimum energy of the epitaxial system is lowered by subvariants of an ordered structure are selected (as atomic ordering at the free surface' 3,4 '. Although these discussed above) or to systems where the ordered energy minimization arguments can predict the structure is only two-fold degenerate. We assume that stability of various structures, the growing film the elements of an equiatomic binary or pseudobinary microstructures observed experimentally rarely alloy are simultaneously deposited by a directed correspond to the equilibrium structure and depend beam. The compositions on the two interpenetrating in a crucial way on kinetic and dynamical processes at sublattices are c, = ((j> + 1) / 2 + ijf and c2 == (<J> + 1) / 2 the free surface. Recently'5"7', strong experimental tjr, defining the composition variable (J) (r) and the evidence has shown that the direction of step motion order parameter ijf (r). The film lattice constant at the surface determines which of the two depends on the composition as af • af( 1 + 7$), and the subvariants of the ordered structure is formed. Hence, substrate misfit is e = (af - as)/as. the spontaneous formation of locally misoriented surfaces and the associated selection of one of the two François Léonard, a g r a d u a t e student in the Physics subvariants' 81 arises due to a coupling between the Dept. at the Univ. of Toronto, is one of three Lumonics Best Student Paper winners at the 1998 atomic ordering and the surface morphology. M C A P Congress. Prof. Rashmi C. Desai is his supervisor. 230 PHYSICS IN CANADA July/August 1 9 9 8 ARTICLE D E F O N D (ATOMIC ORDERING...) The total free energy for the system is ( F 4 » , h, u} = ST 0VXV . s,h = r h v(4) <Fd {t|j, <\>, h, u} + <FGL {t|/, 4>, h} + <FS {h}, where <Fe, is the 5h elastic free energy, 'fGL is the Ginzburg-Landau free energy that represents the phase diagram without The first equation describes the time evolution of the elastic fields, and <FS is the surface free energy. Small non-conserved order parameter. The first term in this displacements around the local equilibrium position equation describes the thermodynamics, while the are represented by the displacement vector u (r). The second and third terms are due to dynamical elastic free energy is that of an isotropic solid, and the processes at the surface. The term aVxh describes the surface free energy has only a contribution from the experimentally observed dependence of ordering on surface tension. The essential properties of the step motion direction, assuming that this selection epitaxial alloy phase diagram are given by <FGL, which mechanism operates in one preferred direction on the must include all of the possible stable phases surface. The term Ft); represents the constant (ordered, disordered and coexisting phase separated deposition of material on the surface, with F phases). For the stability analysis, it is sufficient to proportional to the growth rate. The contribution pVvi|j keep the lowest order terms in and 4>, and the free in Eq. (4) describes the local selection of step motion energy is written as due to the underlying atomic order. The stability of this coupled system of equations is studied by expanding a general variable as £ = S e ' q r and Xi2 dr (i) T linearizing the equations for the Fourier modes % . We GL solve for the dispersion relation using the effective elastic energies computed previously' 10 '. J: The signs of the coefficients r and x determine the stability of the disordered and compositionally homogeneous phases respectively. Since the constant deposition of atoms on the surface tends to mix the atomic species, we look at perturbations around the disordered (4/ = 0), compositionally homogeneous (4> = 0), stressed layer with a planar surface. We take ijf, c|), and h to evolve by surface diffusion only, while u instantaneously satisfies mechanical equilibrium' 101 . The mechanical equilibrium condition allows the calculation of an effective free energy that depends on (J), and h only. In a reference frame moving with the interface, the dynamical equations for the surface order parameter, surface compositions and morphology are 5-F ôtH> -t-aVvh -Fv|/, I and (2) / ST «t* = 0<t> F<|>, Because the three variables are coupled, they evolve with the same dispersion relation, and a morphological instability (stability) of the planar growth front is accompanied by an instability (stability) of the disordered, compositionally homogeneous alloy against atomic ordering and phase separation. The instability can be controlled by increasing the growth rate since the constant deposition of atoms favors the disordered structure at the surface. Figure 1, with parameters chosen to represent GalnP grown in the ordered region of the epitaxial phase diagram, shows that the combination of the film/substrate misfit and the growth rate controls the joint stability/instability of the system. The figure suggests a sharp transition from stable to unstable growth as the misfit is increased beyond a value of 0.02. (3) Experiments' 21 focusing on the effects of the growth rate on ordering show that an increase in the growth rate decreases the degree of order, in agreement with the conclusions of the present work. Experiments' 11 ' also suggest that the degree of order depends on the temperature, with good ordering in a temperature range and weak ordering above and below this range. LA PHYSIQUE AU CANADA juillet à août, 1998 231 FEATURE ARTICLE ( A T O M I C O R D E R I N G . .. ) instability of the system against spontaneous atomic ordering, phase separation and surface deformation. In the future, a nonlinear analysis of the model should provide insight on the experimentally observed formation of alternating (001) oriented laminae of the two subvariants' 51 . 60 40 S ACKNOWLEDGEMENTS 20 2 Unstable es 0I 0.00 L. _I 0.01 . — 1 0.02 0.03 Film/substrate misfit This work was supported by the Natural Sciences and Engineering Research Council of Canada. F. Léonard also acknowledges support from the Walter C. Sumner Fund. REFERENCES Fig. 1 Calculated stability d i a g r a m for G a l n P g r o w n at 803K in the o r d e r e d region of the epitaxial phase diagram. The layer is simultaneously stable against atomic ordering, phase separation a n d surface d e f o r m a t i o n in the s h a d e d area. Since the diffusion constant increases with temperature, a higher temperature corresponds to a smaller effective growth rate, and a stronger instability according to the results of our calculations. This explains w h y the ordering is stronger as the temperature is raised, but fails to predict the decrease in ordering as the temperature is increased further. This implies that an important boundary in the epitaxial phase diagram is crossed as the temperature is increased above the maximum ordering temperature interval. In summary, a non-equilibrium description of the stability of growing films shows the importance of the growth rate in determining the joint stability/ 1. G. B. Stringfellow, in Common Themes and Mechanisms of Epitaxial Growth, edited by P. Fuoss, J. Tsao, D. W. Kisker, A. Zangwill, and T. Kuech (Materials Research Society, Pittsburgh, 1993), pp. 35-46. 2. A. Z u n g e r and S. Mahajan, in Handbook on Semiconductors edited by S. Mahajan (Elsevier, A m s t e r d a m , 1994), Vol. 3, Chap. 19. 3. D. M. W o o d , ]. Vac. Sci. & Technol. B 10,1675 (1992). 4. S. B. Zhang, S. Froyen, a n d A. Zunger, Appl. Phys. Lett. 67,3141 (1995). 5. L. C. Su a n d G. B. Stringfellow, Appl. Phys. Lett. 67, 3626 (1995). 6. G. S. Chen a n d G. B. Stringfellow, Appl. Phys. Lett. 59, 3258 (1991). 7. G. S. Chen and G. B. Stringfellow, Appl. Phys. Lett. 59, 324 (1991). 8. D. J. Friedman, J. G. Z h u , A. E. Kibbler, J. M. Olson, and J. Moreland, Appl. Phys. Lett. 63,1774 (1993). 9 F. Léonard and R. C. Desai, Appl. Phys. Lett., July 13 (1998). 10. F. Léonard and R. C. Desai, Phys. Rev. B 57, 4805 (1998). 11. See for example A. G o m y o , T. Suzuki, and S. Iijima, Phys. Rev. Lett. 60, 2645 (1988). FRONT COVER / PAGE COUVERTURE: "Busy Spiders on a Misty M o r n i n g " by R.L. Brooks, University of Guelph One might think that the work of busy arachnids belongs in an art of biology competition, but the physics is in the un form milky appearance of the webs. This effect is seen in cottage country, in late summer, when the lakes are warmer than the overnight air temperature. Evaporation raises the humidity level past the dew point and condensation occurs on the leaves and webs in the forest. But why do the webs look white? One could imagine the threads with a clear, crystalline look or alternatively one could imagine a rainbow of colours. The first w o u l d indicate that much of the light was passing right through, with some of it being refracted. A rainbow would indicate that much of the light was suffering a single scattering and such scattering has a wavelength dependence to the angle. But a milky look means that the light is suffering multiple scattering, which indicates, because water doesn't do that, that the web itself is involved. The water beading on the threads acts like a lens to focus background light onto the thread which then scatters the light in an arbitrary direction. 232 PHYSICS IN CANADA July/August 1998 LAURÉATS DE L ' A C P POUR 1 9 9 8 1 9 9 8 C A P A W A R D S /LAURÉATS 1998 CAP-INO MEDAL FOR ACHIEVEMENT IN APPLIED DR. KENNETH O. OUTSTANDING PHOTONICS AWARDED TO HILL by D e r w y n Johnson, C o m m u i c a t i o n s Research Centre Kenneth O. Hill graduated from McMaster University, Hamilton, Ontario, with a Ph.D. in Engineering Physics in 1968. He also received his M.Eng. (1965) and B.Eng. (1963) from McMaster University. He joined the Defence Research Telecommunications Establishment (DRTE) in 1968. Dr. K e n n e t h O. Hill In 1968, DRTE was converted into the Communications Research Centre (CRC), the research branch of the newly formed Department of Communications. During his career at CRC, Dr. Hill has served as a research scientist (1968 to 1970), group leader, Optical Data Storage and Signal Processing (1970 to 1975), Manager, Optical Communications (1975 to 1985), and Director, Optical Communications (1985 to 1992). In 1992, CRC became part of Industry Canada, at which time Dr. Hill assumed his current position as Principal Scientist. In the past three years interest in optical fibre Bragg grating technology has skyrocketed, largely due to their use as devices in optical fibre communication systems and as optical fibre sensors. The phenomenon behind this technology, photosensitivity in optical fibres, was discovered in 1978 by Dr. Kenneth Hill. Subsequently, Dr. Hill developed improved fibre grating fabrication techniques and novel fibre-grating based devices. These inventions facilitated the transformation of the discovery into an enabling technology ready for commercial exploitation. Gratings now have a broad range of applications that enhance the performance of optical fibre communication systems and optical fibre sensor systems. In the case of optical fibre communications, they are used in: DE L'ACP POUR 1998 "the stabilization of semiconductor lasers, fibre lasers, fibre Raman lasers, optical amplifiers, narrowband and broadband optical fibre filters, fibre mode convertors, fibre dispersion compensators, fibre polarizers, fibre taps, and optical spectrum analysers." Whereas in optical sensors systems, fibre gratings can be used to sense temperature, strain or acceleration. The advantage of optical fibre grating sensors is that through wavelength multiplexing techniques, the monitoring of hundreds of sensors is feasible. Such a capability is required in order to implement smart or intelligent structures for buildings, bridges, ships or airplanes. Today, more than 20 companies worldwide are involved in the exploitation of applications made possible by the discovery of photosensitivity and its application to photoimprinting gratings. Dr. Hill has received numerous honours and distinctions. In 1991, he was elected to Fellowship in the Optical Society of America (OSA). In 1995, Dr. Hill received the 1995 Manning Principal Award for the discovery of photosensitivity in optical fibres and his pioneering work in optical fibre communications. In 1996, Dr. Hill received the 1996 John Tyndall Award from the IEEE Lasers & Electro-Optics Society and the Optical Society of America. RESPONSE BY KENNETH O. HILL The discovery of the photosensitivity of optical fiber waveguides could not have happened when and where it did (at the Communications Research Centre in 1977) had there not been some tolerance for curiosity-driven research. Initially photosensitivity was perceived as little more than an interesting phenomenon discovered by accident. The irony for the prognosticators of that day is that our small R&D group at CRC receives a proportion of the revenues accrued from the photosensitivity technology licenses and royalties. Our group's R&D budget on a per-capita basis is now probably the largest in CRC! It is my experience that a valuable technology in its early stages of development is difficult to recognize LA PHYSIQUE AU CANADA juillet à août, 1998 233 1998 C A P AWARDS even by those w h o depend on technological advances to compete successfully. Those not intimately connected with a technology will tend to have difficulty deciding whether on not it will prove useful in the future. For example, not long ago licenses for photosensitivity technology were offered to industry at $5000 a license. There was a singular lack of interest, in the market place at that time. Nevertheless, we knew that the technology was more valuable than the $5000 offering price. At about the same time, our R&D budget was being cut and w e had difficulties raising f u n d s to patent an important new idea connected with fibre grating manufacture. The prevailing view in Canada at the time, was that you did not patent intellectual property unless industry had expressed an interest in it, i.e. industry knows best. Adherence to such a policy would have been a disaster in the case of photosensitivity. As a general rule, I think scientific training and R&D should be focused on those areas that have been identified through formal studies and national debate as offering potentially the best returns to society over a reasonable time span. However, some allowance has to be made in the research f u n d i n g and selection process for the decision of a individual scientist to pursue what is termed curiosity-driven research. It is indeed, a rare and fortunate scientist whose training and selfinterest overlaps with national priorities. In the past, I have felt that the National Research Council of Canada was an organization that had such a policy and allowed for curiosity-driven research. What may have been missing was the marketing of the products of research. Wasn't Plexiglas discovered at NRC? And what about Alex Szabo's outstanding work in spectroscopy and its link to advanced optical memories? The failure to exploit results of curiosity-driven research doesn't mean w e shouldn't permit it. I am very proud to be the recipient of the inaugural 1998 C A P / I N O Applications of Photonics Medal. For me it represents a very welcome symbolic commitment by both organizations to foster increased emphasis by Canada's scientific community on the application of science in general and photonics in particular. I hope this emphasis leads to applications of the broadest possible sort, and does not exclude the extension of knowledge which often results from curiosity-driven research. Ideally, I would like to 234 PHYSICS IN CANADA July/August 1998 think that photosensitivity might have been a contender for the C A P / I N O Medal had it existed when photosensitivity was discovered in 1977. Photonics is a field that is at the forefront of important technology changes in the world, in telecommunications, information processing, and sensors. It offers excellent opportunities not only for systems and device oriented R&D, but also for curiosity-driven research with potentially big payoffs. One thing that comes to mind is photonic bandgap materials with their promise to revolutionize technology for forming optical circuits; perhaps in the future this technology will supplant photosensitivity in some if not all its applications. Photonics is very much an important technology in the future. It is with great pleasure that I thank all the current and former members of my group at the Communications Research Centre for their tremendous contributions to photosensitivity technology, the Business Development Office of CRC, Canadian Patents and Development Ltd., McMaster University, Ecole Polytechnique, Ontario Laser and Lightwave Centre and Dr. Gerry Meltz formerly of United Technologies Research Center for many very useful discussions. Without their help I would not be here today. A thanks is due as well to the Canadian Association of Physicists and the Institute National d ' O p t i q u e for the honour and great day they have bestowed upon me. Merci. 1998 CAP-COMP MEDAL PHYSICS PETER FOR OUTSTANDING AWARD TO J.S.C. KIRKBY SERVICE (JASPER) MEMORIAL TO CANADIAN MCKEE by Robert C. Barber, University of Manitoba Professor J.S.C. (Jasper) McKee was born in Belfast, Northern Ireland. He received his B.Sc. (Honours) and Ph.D. from Queen's University in Belfast in 1952 and 1956 respectively. He was awarded a D.Sc. from Birmingham University in England in 1968. After spending two leave periods Dr. J. S. C. (Jasper) McKee LAURÉATS DE L ' A C P POUR 1 9 9 8 from Birmingham University as a Visiting Professor at the University of California, Berkeley, Dr. McKee joined the Physics Department at the University of Manitoba in 1974 where he has remained until his retirement in 1997. From 1975 to 1997 Prof. McKee was also the Director of the Cyclotron Laboratory and Accelerator Centre, at the University of Manitoba. Dr. McKee continues his association with the University of Manitoba as a Professor Emeritus. The service of Professor Jasper McKee to Canadian physics and to the Canadian Association of Physicists is well-known and substantial. His service within the Canadian Association of Physicists has included membership on the CAP Council, chair of the Nuclear Physics Division, President in 1986/87, and, since 1990, Editor of Physics in Canada. To all of these activities Jasper McKee has brought his characteristic combination of creativity and boundless enthusiasm. As Editor he has overseen the rejuvenation and evolution of Physics in Canada. Under his leadership, the journal has become a more exciting and readable journal, and has improved significantly in its attractiveness and relevance to the community of Canadian physicists. Physics in Canada has become a key element in answering the question "What does the CAP do for physicists in Canada?" Aside from his CAP involvement and such initiatives as the "Art of Physics" competition, Professor McKee is well known for his n u m e r o u s contributions to the public awareness of science through his exemplary work on CBC, especially on radio both locally and nationally, as well as through television work on CBC News World and, more recently, as a consultant to the Discovery Channel. During the past year The Royal Society awarded him the McNeill Medal for the promotion of the public awareness of science. He also holds an unlikely (for a physicist) award, an Actra Award (1972), as runner-up for best broadcaster on radio. In addition to the activities mentioned above, Jasper McKee was invited to serve on the National Advisory Board on Science and Technology in 1994/95, as one of only two members, out of nineteen, whose primary function is that of professor. Thus, on this occasion, he represented not only the physics community, but the wider community of practising scientists in a vital advisory role to the Prime Minister. He has an enviable reputation as a teacher and has an impressive record as a researcher in few body physics and applied nuclear techniques. He has recently been appointed a Director of Atomic Energy of Canada. In keeping with the spirit of this award, we note that Professor McKee has been exemplary in every respect of his professional career for his integrity, his concern for colleagues, his cooperation with colleagues, and his infectious enthusiasm for physics. RESPONSE BY JASPER MCKEE It is both an honour and a humbling experience to receive the Kirkby Award, particularly as I knew Peter well and had the greatest admiration for his many abilities. He was a great guy. He was not only the conscience of the CAP throughout his many years on Council, but he was an ever present help in every time of need to presidents and executive committees. He continually reminded them that Council was the policy-making body of the CAP. This was a useful check on the potential excesses of executives and I certainly, during my year as President, not only learned a lot from Peter but sought his advice on many occasions. It was at his instigation that a record of all motions passed and approved by the CAP Council was kept and updated on a regular basis. With this in hand, it was possible for the first time to respond to government requests for input on policy issues because we had, at last, a record of the CAP position on specific matters and could respond realistically to questions that we were asked. The person w h o should be receiving this award tonight is however not me but the man for whom it is named, Peter Kirkby. It was a sad day for the CAP when he met a tragic death in 1995 while working at his farm in Ontario. The presence of Peter's wife, Joan, at this banquet is singularly appropriate as we remember again his fundamental contributions to the growth and development of the Association. In conclusion, I would like to thank the Canadian Association of Physicists for the award of the Kirkby Medal. I would also thank their partner in this act, the Canadian Organization of Medical Physicists, with w h o m I have had a continuous if tenuous association. It is a delight for me to discover that four LA PHYSIQUE AU CANADA juillet à août, 1 9 9 8 235 1998 C A P AWARDS of the twelve PhDs that I have supervised so far are now in senior positions in the medical physics community in Canada. I wish them all continued success in their careers. Thank you, again, for this great honour of which I am very proud. 1998 CAP-CRM MATHEMATICAL PRIZE IN THEORETICAL PHYSICS AWARDED TO J. AND RICHARD Universe, the intergalactic medium, and supermassive objects. His research is characterized by rigour, mathematical sophistication, and physical insight. Dr. Bond has played a leading role in the Canadian cosmology community over the past decade.Ten years ago, there was virtually no research activity in physical cosmology in Canada; now Canada is among the leading countries in the world in this subject.Dr. Bond deserves much of the credit for this dramatic growth. BOND by Scott Tremaine, Canadian Institute for Theoretical Astrophysics (CITA) J. Richard Bond received his B.Sc. in mathematics and physics from the University of Toronto in 1973. He attended graduate school at Caltech where he received his Ph.D. in theoretical physics in 1979. Since 1985 he has been a Professor in the Canadian Institute for Theoretical Astrophysics (CITA) at the Prof. J. Richard Bond University of Toronto, with cross-appointments to the Departments of Physics and Astronomy. He has also been a Fellow in the Canadian Institute for Advanced Research Program in Cosmology and Gravity since 1986. He has been Director of CITA since 1996. Dr. Bond has made fundamental contributions to a wide variety of theoretical problems in physical cosmology and other areas of astrophysics. He has applied the theory of Gaussian random processes to study the development of linear structures in the Universe and has devised powerful mathematical tools for understanding and characterizing nonlinear structure. He has emphasized the dominant role that the angular power spectrum of the cosmic background radiation (CBR) can play in testing theories of structure formation and determining the scale, age, and mass content of the Universe. The CBR will be investigated by two satellite and many ground-based observatories over the next decade, and Dr. Bond has developed much of the mathematical machinery that will be used to interpret these observations. H e has contributed to our understanding of the nature of dark matter in the 236 PHYSICS IN CANADA July/August 1 9 9 8 Dr. Bond has received a number of honours including a Sloan Research Fellowship, the E.W.R. Steacie Fellowship, the Steacie Prize, and the Carlyle S. Beals Award of the Canadian Astronomical Society. He is a Fellow of the Royal Society of Canada. RESPONSE BY RICHARD BOND I first want to pay homage to the powerful role played by the Canadian Institute for Advanced Research through its Cosmology and Gravity Program. By 1984, I had reconciled myself to spending my research career in the US. Two events convinced me that a great resonance was possible in Canada, the wisdom of NSERC in supporting the Canadian Institute for Theoretical Astrophysics, and the appearance of Fraser Mustard, the CIAR president, in my office at Stanford to describe how cosmology would be the second CIAR program because of its grand interdisciplinary sweep from the ultradense and ul trahot of the very early universe to the ultradilute and ultracold of intergalactic space. It is rather remarkable that the first 4 winners of this Prize are the first 4 Fellows of the CIAR Cosmology Program, 2 recruited back to Canada from the US. And I also want to acknowledge the current CIAR President, Stephane Du pre, for his strong belief punctuated by concrete action that the Canadian resonance in cosmology will continue to grow. I did my PhD at Caltech under Willy Fowler who has had a profound influence on me. This was not just because of his Nobel Prize winning science that cracked for all time the mystery of the origin of the elements. I can only hope that when I look back on my career I can say we have cracked the equally mysterious: how did structure arise in the cosmos, and incidentally what is the dark matter. With the incredible precision offered by new cosmic microwave LAURÉATS DE L ' A C P POUR 1 9 9 8 background satellites and other telescopes, we have good reason to be optimistic. The greater impact of Willy was his powerful positive spirit that generated around him a grand centre for postdoctoral fellows and graduate students. We to think we have done something similar with CITA, maintaining the high level intensity of the best of the US places, but in a positive friendly environment with a distinctly Canadian twist and without intellectual chest-thumping. We have by now trained about a hundred postdoctoral fellows in all areas of astrophysics, w h o n o w are spread across Canada and throughout the world, networked back to Canada. I am especially pleased to be acknowledged with the CAP/CRM Prize, since apart from the coupling of mathematics with physics that has fueled much of my work, I think we should recognize that old disciplinary boundaries are melting, and a good umbrella for intellectual unification is mathematical sciences. Especially evident is the common language of computation so important for taking our early universe theories forward through the linear into the highly nonlinear and dissipative to confront head-on the observables associated with the data that is now just pouring in, and about to turn into a flood in the next decade. Cosmological research is in its golden age, and we who work in those few decades when humans have developed the tools to ask and answer questions of origin are in a state of rare privilege. But there are limits to the hubrus of physicists: adopting a phrase from another great cosmological spirit, John Wheeler, can we derive "it from bit", that is can a full theory of the universe be learned from just that tiny patch we get to access because of speed of light constraints, a patch so awesomely vast by any other standards than that of the theorist. 1998 CAP MEDAL EXCELLENCE AWARDED IN TO S. FOR TEACHING PEDRO GOLDMAN by Donald Moorcroft, University of Western Ontario Professor S. Pedro Goldman was born in Buenos Aires, Argentina, and came to the Department of Physics at the University of Western Ontario in 1983, following studies at the University of Buenos Aires, the Israel Institute of Technology, Haifa, and the University of Windsor. He has been a Full Professor at the University of Western Ontario since 1993. He specializes in accurate calculations in relativistic atomic physics, many electron systems and atoms in high magnetic fields. Pedro Goldman did his first teaching in 1983-84; at the end of the year the students insisted on nominating him for a teaching award. In 1994, the Student Council of the Faculty of Music established the S.P. Goldman Annual Award for Excellence in Teaching, and named Dr. Goldman himself as the first winner of the award. In 1996 he won the Edward G. Pleva Award for Excellence in Teaching, the pre-eminent teaching award at the University of Western Ontario. This award recognizes Professor Goldman's outstanding achievements as a teacher both inside and outside the classroom, as well as his contributions to course development. Pedro Goldman has proven to be an outstanding classroom teacher at all levels, from introductory first-year physics to graduate-level quantum mechanics, from a service course for music education students to honours-level modern physics. In his lectures, Pedro communicates his love for the subject matter with engrossing stories and an infectious sense of humour. Students remark particularly on his ability to explain difficult concepts in terms which he adjusts to the student's level of understanding. Course development and teaching come together in the course on "The Physics of Music and Sound". In this stunningly successful course, Professor Goldman has carefully tailored the physics to match the needs, abilities, and strengths of the music students he is teaching. Two quotations from music students convey the extra dimension he brings to his lectures, and the personal rapport he establishes with his students. ". . . the greater thing which Dr. Goldman has taught us is that the very nature of music itself is the manifestation of laws which govern the universe. And the laws of the universe are infinitely beautiful." "We are going to miss taking his class, but even more importantly we are going to miss him." Prof. S. Pedro Goldman LA PHYSIQUE AU CANADA juillet à août, 1998 237 1998 C A P AWARDS RESPONSE BY PEDRO • GOLDMAN It is a great honour to receive this award from the CAP. Teaching is a very special endeavour with unique qualities: the satisfaction to give, the strive to inspire, the successes, the disappointments, the emotions, the h u m a n contact. Because of these, to teach has become an essential part of my life so that this recognition has a very deep meaning for me. I thank the CAP wholeheartedly. I would like, in these few lines, to state my firm conviction on the value and importance of classroom lectures. For the last several years there is a common message in the talks on teaching University Physics at our weekly departmental colloquia. We are told that students do not learn much from classroom lectures, which are presented as an antiquated method to which w e adhere out of habit. In its place new techniques are presented, with statistics showing their superiority over classroom lectures (which anyway do not accomplish much) I think that the most important misconception about lectures is that their main role is to deliver information to the students. Yet for the passage of information, lectures are not essential. The student can obtain information from books, and could, in principle, be guided by means of handouts to ensure a proper rate of gathering of information, the appropriate choice of material and a good collection of exercises and problems to solve. dt ôqi • • Consider, as an example, the introduction of Lagrangian Mechanics to Physics students. The material (for conservative systems without constraints) consists of the following: 238 PHYSICS IN CANADA July/August 1 9 9 8 âq, where s is the number of degrees of freedom and L is the Lagrangian. L = T - V where T is the kinetic energy and V is the potential energy. Different mechanical systems are characterised by different forms of V. This is it! I knew a Physics professor that used to present the Lagrangian formalism as nothing else than a 'cute' mathematical tool with no physical content. He would then go on to present and solve all kinds of problems using the Lagrangian formalism. Here you have an example of somebody conveying information rather than teaching. In this case actually also doing harm to his class. Consider instead • Introducing the Principle of Least Action as a general principle • • • There is, however, another fundamental role to classroom lectures: to motivate and to inspire. It is our primary role as teachers to communicate our enthusiasm for Physics to our students and to become an inspiration by relaying to the students our thoughts and our insight on the material w e teach. It doesn't matter if w e are teaching friction in a first year Physics course, or Fourier analysis in a course of Physics for Musicians, or self-energy in a graduate course in QED: our strive to teach the essence of Physical thought must always be there. the Lagrange equations • • • of nature t h a t l e a d s to t h e Lagrangian concept. Discussing the reliance of any Physical theory on a priori stated hypotheses. Stressing the fundamental nature (from a physical and a philosophical perspective) of inertial frames of reference. Discussing the impossibility (within this theoretical framework) of defining an absolute frame of reference. Discussing time and how it leads to the definition of Energy and its conservation. Introducing the fundamental importance of symmetries in nature and how, in the most amazingly natural way, they define physical quantities that are conserved. Presenting the fact that the same Lagrangian formalism works for any theory in Physics. Building new theories on the basis of symmetries and the resulting conserved quantities. Invariably students are amazed at the beauty and power of these concepts. If we manage to create in class this magical atmosphere of amazement; if we manage to transmit our own exaltation at the sheer LAURÉATS DE L ' A C P POUR 1 9 9 8 beauty of the material; if w e manage to make the class feel the unique experience of the pursuit to unravel the mysteries of the Universe; if we manage any of these, then we are teaching. When we as teachers achieve this, we have given to our students something that touches them very deeply and will stay with them for ever. On the other side, we are as much touched by these deep, transcendental moments given that the elevation of students and teacher is inevitably mutual. 1998 HERZBERG MEDAL TO LOUIS TAILLEFER by J. Carbotte, McMaster University Louis Taillefer received his B.Sc. (Honours) from McGill in 1982 and his Ph.D. from the University of Cambridge in 1986. In Cambridge, he was a Research Fellow of Jesus College and spent over a year working as an NSERC Postdoctoral Fellow at the Cavendish Laboratory. In 1987, he went to Grenoble, Dr. Louis Taillefer France to work in the CNRS Laboratories, first as a postdoctoral associate and then as a Research Scientist at the Laboratoire Louis-Néel. Dr. Taillefer returned to Canada in 1992 to join the Department of Physics at McGill and the Superconductivity Program of the Canadian Institute for Advanced Research. Dr. Taillefer's main research interest is in the field of superconductivity. In recent years, three families of unconventional superconductors were discovered: the organics, the heavy fermion compounds, and the famous high-Tc oxides. These have novel properties such as strong electron interactions, multiple phases, states with new symmetries - which challenge our fundamental understanding of how electrons behave, and offer the possibility of exciting new technology. Taillefer has m a d e significant contributions to this field. While at Cambridge, he was the first to observe directly the heavy electrons in heavy-fermion systems via the de Haas-van Alphen effect in UPt3, a unique instance in solids, which gave birth to the most active research area in heavy fermion physics. With collaborators in Grenoble and Karlsruhe, he was able to show that at the heart of this phenomenon is a coupling between antiferromagnetic order and superconductivity. At McGill, Taillefer's group of students and associates has used heat conduction to investigate both heavy-fermion and high-Tc superconductors. By looking at the anisotropy of heat transport in a single crystal of UPt3, they were able to determine the symmetry of the order parameter. In the oxide YBa2Cu307, their low-temperature measurements revealed the existence of a residual normal fluid deep in the superconducting state, shown to exhibit universal conduction, independent of scattering rate. Dr. Taillefer combines two essential ingredients for successful metals physics research: he has an unusual talent for producing single crystal samples of the highest purity and perfection, and he is a master of a battery of sophisticated experiment techniques. Some of these techniques utilize the in-house, low temperature facilities that he has built at McGill, and others involve collaborations at major facilities such as neutron beam facilities and synchrotrons. In 1993, Dr. Taillefer was awarded a Research Fellowship by the Alfred P. Sloan Foundation and, on April 27th, 1998, received an NSERC Steacie Fellowship. RESPONSE BY LOUIS TAILLEFER I feel greatly honoured to have been awarded the Herzberg Medal, and I would like to express my deepest gratitude to the Canadian Association of Physicists. I am also very grateful to Jules Carbotte, of McMaster University, first for nominating me, and also for the continuous support he has given me as Director of the Superconductivity Program of the Canadian Institute for Advanced Research (CIAR), of which I have been a member ever since I returned to Canada in January 1992. The CIAR is a tremendous invention and a miraculous success. By bringing together the best physicists working on superconductivity in Canada, the Superconductivity Program provided for me a most stimulating environment, which has made all the LA PHYSIQUE AU CANADA juillet à août, 1998 239 1998 C A P AWARDS difference in my attempt to build a new research effort on strongly correlated electrons at McGill. The work for which this award is given was performed in England, France and Canada over a period of 15 years, and it was the result of numerous collaborations. I cannot acknowledge all of these here, but there is one defining influence I must mention: that of Gilbert Lonzarich, my Ph.D. supervisor at the University of Cambridge, w h o was the most inspiring example of a passionate and outstanding scientist and w h o set the highest standards for scientific endeavour. I have been fortunate to have attracted excellent students and research associates to my laboratory at McGill over the years, and much of the recognition should go to them. Most of the pleasure of doing research was certainly from working with them. This award could not have come at a more exciting time. Our current research activities, related to transport properties in unconventional superconductors, are producing some of the most exciting results in my career. NSERC has never been so generous. The CIAR program on Superconductivity has just been renewed for another five years. And our group will be setting u p a n e w lab at the University of Toronto this fall, with the prospect of an ambitious concerted effort at studying correlated electrons and their weird and wonderful ways. In closing, I would like to take this opportunity to thank McGill University, and in particular the Department of Physics, for never failing to support my research activities throughout the enjoyable and productive years I have spent there. 1998 CAP MEDAL ACHIEVEMENT DR. ERNEST OF AWARDED R. TO KANASEWICH by J. Tuszunski, University of Alberta Ernest R. Kanasewich received his B.Sc. in physics in 1952 and an M.Sc. degree in 1960, both from the University of Alberta. In the period from 1952 to 1956 he worked as a geophysicist with Geophysical Dr. Ernest R. Kanasewich 240 PHYSICS IN CANADA July/August 1998 Service International Corp. He then went on to obtain his Ph.D. from the Department of Physics at the University of British Columbia in 1962. Following his doctoral work he has been at the University of Alberta from 1963 to the present time as a faculty member rising through the ranks to eventually become full professor. In the meantime he also held the position of a research associate professor at the California Institute of Technology from 1969 to 1970 Furthermore, he was acting Chairman of the Department of Physics at the University of Alberta from 1973 to 1974 and Chairman for the term of office from 1990 to 1996. In addition, he held the post of Director of the Institute of Geophysics, Meteorology and Space Physics from 1991 to 1992. Dr. E.R. Kanasewich has been extraordinarily active as an internationally recognized researcher in his field of study - geophysics. His major research activity involved imaging of the Earth's crust with the use of seismic waves through elastic and anelastic porous media. Much of this effort was carried out within the national geoscience project called the LITHOPROBE. A related applied activity in which Dr. Kanasewich has been prominently involved is the use of seismic tomography to the investigations of oil sands deposits. A major part of these research projects utilizes computer based methods of data enhancement and signal analysis. Over the years, he has published more than 135 papers in some of the best journals in the area and authored 3 books, the latest of which was published by Alberta Energy and is called "Seismic Imaging of In Situ Bitumen Reservoirs and the Properties of Porous Media". For his outstanding quality work Dr. Kanasewich received numerous honours and distinctions. He was appointed Fellow of the Royal Society of Canada in 1975 and has been granted Honorary Life Membership in the Canadian Society of Exploration Geophysicists and also the SEG. He was awarded the J. Tuzo Wilson Medal in 1988 and named McCalla Professor of the University of Alberta in 1989. Ernie Kanasewich has been instrumental in building an international reputation for the geophysics program at the University of Alberta. His numerous graduate students and research associates came from a number of countries around the world and found not only a high-level of expertise and professional LAURÉATS DE L ' A C P POUR 1 9 9 8 development but also excellent employment opportunities. His 20 former Ph.D students and 12 M.Sc. students are all professionally employed in the area of geophysics at universities in Canada and abroad, as well as in the Industry and government laboratories and institutes. Although Ernie has recently retired as Professor Emeritus, he still supervises a Ph.D. student and a research associate and is working on Lithoprobe and Oil Sands research. Ernie has been an inspiration to his students and colleagues alike for his hard work and unparalleled dedication to his field of study, his University and the Department of Physics. We hope to be able to benefit from his advice for many years to come. RESPONSE BYE.R. KANASEWICH It is such a great honour to be the recipient of the gold medal for achievement in physics. This is particularly the case for a geophysicist w h o switched from an interest in astrophysics to the field of earth sciences. Despite the entirety of my research being in geophysics, I did publish a couple of papers involving Dirac cosmology. I am the beneficiary of the encouragement that I obtained from Dr. Don Betts, when he was a theoretical physics professor at the University of Alberta, to continue on to a PhD program. The courses given by both Dr. Garland and Dr. Betts are among the finest I have received and I still treasure their lecture note. At the University of British Columbia the active support of my supervisor, Don Russell and his colleagues, Jack Jacobs and Jim Savage, were also important to my development as an active researcher. Colleagues at the Universities of British Columbia, Victoria, Calgary, Saskatchewan, Manitoba, Western Ontario, Toronto, Dalhousie and Memorial were particularly helpful in the many collaborative programs in which I participated or initiated. Outside of Canada I would like to mention the support of colleagues at the California Institute of Technology and Dr. F. Abramovici of Tel Aviv University. Colleagues at the Earth Physics Branches in Bedford, N.S., Ottawa and Sidney, B.C. were essential contributers to much that I have done. It has been a very exciting time to be involved in the earth sciences at a time when major breakthroughs involving plate tectonics have changed our perception of geodynamics. We can look to the future with continuing excitement as new technology allows us to tackle the solid state and fluid properties of a planetary body. Computers are being made available which allow us to image the earth in three dimensions and to predict its evolution with time. Field instrumentation, both from satellite telemetry and ground based seismic and electromagnetic measurements will be heavily involved in producing sound data for theoretical tests. Canada, with its large segment of the North 'American plate will be a vital testing ground for theories into the evolution of continental lithosphere. We need, particularly, to emphasize our northern land mass in future scientific support at the national level. I would like to take this opportunity for thanking Dr Jack A. Tuszynski, who nominated me for the award and to Dr Helmy S. Sherif and Dr. John C. Samson who were involved in the process. It is a great pleasure to acknowledge the support received from the national research agencies, NSERC and the Geological Survey of Canada. The continuing support by NSERC for the next four years as an emeritus professor allows me to continue actively in scientific research and serves as a very positive incentive at a time w h e n I still have new ideas to develop and older programs to complete. The provincial government, through Alberta Energy, and its joint industry-government program, AOSTRA, have been the source of very substantial aid for my Seismology Laboratory at the University of Alberta. The help of many colleagues, both at the University of Alberta and at other universities across Canada was of great benefit to anything I have accomplished. The very sound grounding in geophysics and in research methodology that I received from Dr. George Garland during my Master's program w a s of great benefit. The support of my wife, Elaine and my two children, Anthony and Patricia has been an essential element, throughout my career. Finally a great thank you to the CAP for this honour. LA PHYSIQUE AU CANADA juillet à août, 1998 241 NEWS N E W S / NOUVELLES PROCEEDINGS FROM IUPAP SPONSORED CONFERENCES 1996-97 Proceedings from international conferences are often published and distributed in a way that does not make them easily available to physics libraries and the physics community. IUPAP has studied the problem and issued recommendations to overcome it. Still the problem remains and IUPAP is often approached by interested parties to advise them how proceedings from IU PAP sponsored conferences can be acquired. For this reason all organizers of IUPAP sponsored conferences have been requested to inform the office of the Associate Secretary-General about the publication of proceedings. The following list comprises information for the published proceedings for conferences held in 1996 and 1997 for which this information is already available. The conferences are numbered as they appeared in past News Bulletins (NB95-2 and NB96-2) which contained official lists of IUPAP sponsored conferences for 1996 and 1997. Conference organizers who have hot yet transmitted the information about proceedings of 1997 conferences are kindly requested to do so at their earliest convenience. The comprehensive list of conference proceedings for 1995-97 is also available on the IUPAP web site at http://www.physics.umanitoba.ca/IUPAP/confproc.html Cette Revue est disponible sur microfilm ou microfiche Les volumes antérieurs de cette publication sont également disponibles sur microfilm ou michrofiche. C O M M I T T E E T O E N C O U R A G E W O M E N IN PHYSICS EXTENDS T H A N K S The Committee to Encourage Women in Physics (CEWIP) would like to thank the physics departments at the following institutions for their contributions in support of our committee. The donations we received helped make this year's CEWIP Women in Physics session, which was held on June 15 at the 1998 CAP Congress at the University of Waterloo, possible. Pour de plus amples renseignements, i 'euillez communiquer avec : Acadia University Brock University Lakehead University Laurentian University McGill University University of Montreal Univ. of New Brunswick University of Ottawa University of Toronto Waterloo University Univ. of Western Ontario Windsor University CEWIP would like to organize such events at every Annual Congress and with the donations we obtained this spring, we should be able to continue this tradition for another two years. At the 1999 Annual Congress, we hope to organize a Women in Physics plenary session to ensure that no conflicts arise with other sessions, and to allow more time for interesting seminars. CEWIP, whose membership has been composed of both men and women since its inception in 1983, has been involved in many activities. We are currently in the process of assembling a CEWIP web page that will be accessible from the CAP web site. We are also compiling a database of Canadian women physicists and updating the Directory of Women in Physics in Canada. This database will allow registrants to establish networking either by discipline or region. It will also be used to fulfill requests the CAP receives to forward job advertisements to the individuals listed in the Directory of Women Physicists. Anyone wishing to be included in the Directory of Women Physicists may contact the CAP office for a registration form. Wendy Taylor, Chair, Committee to Encourage Women in Physics 242 PHYSICS IN CANADA July/August 1998 ift Micrornedia Limited Canada 's Information People 20 \ ictoria Street. Toronto, Ontario M5C2S8 (416)362-5211 1-800-387-2689 RÉSUMÉS CORPORATIFS CORPORATE PROFILES / RÉSUMÉS CORPORATIFS A N S TECHNOLOGIES Les technologies Company Background The company was founded in 1983 and is a privately owned Canadian Technologies corporation. The head office is located in Fredericton, N.B. and branch offices are maintained in Saint John, N.B. and Montreal. The ANS Technologies group of companies include: A N I Q Atlantic Nuclear Services Ltd., Saint John, N.B. ANIQ R&D Inc., Montreal, Quebec Business Areas Wear and Corrosion Monitoring using Thin Layer Activation (TLA/SLA) Signal processing, image enhancement and machine intelligence. Remote monitoring, diagnostics and intelligent control systems. Software engineering, independent verification, validation and testing, quality assurance and system integration. Engineering analysis for reactor physics, thermalhydraulics, structural design, reliability and safety assessments. Environmental science, monitoring systems, socio-economic impacts a n d risk assessment. Nuclear science including laboratory and measurement services for the medical, environmental, process and manufacturing industries. Technology Development: ANIQ R&D ANS Technologies recognizes the need to adopt sophisticated information technologies for advanced industrial applications. To enhance the company's technical expertise, ANS has formed a new company based in Montreal that is responsible for the research and technology development programs of the corporation. R&D is funded in the following areas. • • • • • • • Computer simulation and data visualization Thin Layer Activation software and hardware development Study of aerosols in a microgravity environment Intelligent machines Remote monitoring and diagnostics Software engineering. ANS supports an NSERC University/Industry R&D program, in Signal Processing at the Université de Montréal. Thin Layer Activation Technology The efficiency and reliability of machine parts and industrial equipment is significantly affected by wear and corrosion. A reliable and on-line measure of wear and corrosion can result in substantial savings in time and money during the development of machine components and lubricants, or static parts subject to corrosion. Moreover, on-line monitoring may be used to minimize costly downtime and unscheduled interruptions during a component's lifetime. For this reason, ANS offers a complete industrial service based on Thin Layer Activation (TLA), which is far superior to traditional techniques for monitoring wear and corrosion in the development of mechanical components and the maintenance of critical parts. A thin layer and pre-selected area of the surface of the component is labeled with radio-isotopes. This is done without significantly affecting the mechanical or chemical properties of the part. The activity so created is extremely low and poses no hazard to staff. Once the activated part has been installed and the machine reassembled, specific measuring equipment can detect the gamma rays emanating from the induced activity. During the wear or corrosion process, the loss of material results in a loss of activity at the surface of the part and an accumulation of activated particles in the lubricant. By placing a gamma ray detector near the activated component or near the lubricant circuit reservoir or filter, the movement of the activity is very precisely measured. These measured values are computer-processed rapidly, and the on-line monitoring of the degradation is delivered by a user-friendly software in a comprehensive and informative manner. TLA technology represents a significant breakthrough for industry. The system is able to deliver a non-contacting and continuous measurement of wear and corrosion, even for parts at inaccessible locations. The results are extremely precise (0.1 pm - 0.01 pm). Moreover, the exact location of the loss is known. The measurements are performed under real operating conditions, and our system is capable of monitoring and recording critical operating parameters along with the degradation data. For more information on TLA or our other products and services, visit us at our web site http://www.lps.umontreal.ca/ANS or contact Dr. Keith Scott at 506-458-9552, or Dr. Kenneth Oxorn at 514-343-7669. LA PHYSIQUE AU CANADA juillet à août, 1998 243 CORPORATE RÉSUMÉS SYST=ms inc. C T F SYSTEMS Company Background CTF Systems Inc. was founded in 1970 by a group of professionals with backgrounds in physics and electronic engineering. Since its beginning the company has enjoyed a steady growth in size, experience and technical expertise. The goals of the company have been to undertake the development and manufacture of instrumentation and systems allied to the fields of applied physics and electronics. Over the years these goals have materialized through various internal development projects, commercial sales and R&D contract opportunities into the areas of superconducting devices, biomagnetometers, military magnetometer/gradiometers, geophysical magnetometers etc. Most products have been based on superconducting quantum interference device (SQUID) sensors. CTF Systems Inc. presently occupies over 2300 m2 of facilities for production, engineering and administration in an industrial complex located in Port Coquitlam, near Vancouver, BC. MEG Systems Currently CTF primarily manufactures whole-cortex MEG systems. It is one of only three companies worldwide capable of producing such systems. MEG technology gives the most precise functional information on the brain's electrophysiology. Unlike other brain imaging techniques, MEG systems are completely noninvasive and pose absolutely no risk to the patient. MEG may be used for presurgical functional mapping, neuropharmacological investigations, pathological functional deficit, trauma and epileptic assessment, along with many types of neurological research investigations. More Information More information about CTF Systems Inc. and MEG is available by contacting: Gordon J. Haid Marketing Manager CTF Systems Inc. 1 5 - 1750 McLean Ave. Port Coquitlam, BC Canada V3C 1M9 Tel: (604) 941-8561 Fax: (604)941-8565 Email: [email protected] or by visiting the CTF web site at: www.ctf.com. G Gamble Technologies The MEG sensors are mounted in a helmet-shaped cryogenic dewar. The dewar may be tilted to allow for examinations in either the fully supine or seated position (or any intermediate angle). Similarly, the patient support adjusts to accommodate the operating angle of the dewar. Electronics and software for acquisition, data interpretation and modeling is also manufactured by CTF. 244 PHYSICS IN CANADA July/August 1998 LIMITED Gamble Technologies Limited (GTL) is a wholly owned Canadian corporation providing instrumentation solutions in a number of overlapping technology areas. The company is anchored by its representation of the companies of EG&G INSTRUMENTS based in Oak Ridge, TN and Eberline Instruments in Santa Fe, NM. Early in 1998, GTL became the distributor for Andor Technology of Belfast, Northern Ireland and Oriel Instruments of Stratford, CT strengthening its optical products offerings. Instrumentation & Systems For Nuclear Analysis • • • CTF's most advanced system simultaneously measures the entire cortex with both low noise magnetic detectors and EEG electrodes. The system includes 151 SQUID sensors, 29 SQUID references, 64 unipolar EEG channels, 8 bipolar EEG channels (suitable for EOG or EMG), 16 multipurpose ADC channels, along with 16 trigger inputs and outputs. All channels are measured simultaneously. GAMBLE TECHNOLOGIES • • EG&G ORTEC Leaders in nuclear instruments, detectors, systems; gamma and alpha spectrometers, Windows software, networked systems Hidex OY Triathler LSC / Gamma Counter / Luminometer, unique compact instrument ORDELA, Inc. PEFRALS alpha measurement system - lowest background and highest figure of merit obtainable for alpha measurements Sparrow Corporation Multi parameter software for Mac & Windows95/NT. Drivers for common VME and CAMAC instruments. Teledyne Brown Engineering Nal Detectors, TLD systems Health Physics & Radiation Measurement Systems • • Eberline Instruments Radiation Measurement Systems for health physics and industry ESM Eberline Radiation Measurement Systems for health physics and industry RÉSUMÉS CORPORATIFS • • • • Hidex OY Triathler LSC / Gamma Counter unique portable system National Nuclear Corp. Industrial radiation measurement systems Teledyne Brown Engineering Compact, low cost Windows based TLD systems Xetex, Inc. Radiation measurement system for health physics and industry INSTRUMENTATION FOR OPTICAL A N D METROLOGY Innovative Vacuum Technology LEYBOLD CANADA INC. The history of Leybold began with the establishment of two separate firms, one in Cologne in 1850 and one in Hanau 1851. APPLICATIONS • • • • • Andor Technology Limited Advanced Scientific CCD Cameras for Imaging & Spectroscopy featuring the most compact design available in a scientific camera. TE cooling to -90(C available without periodic vacuum pumpout or nitrogen purging EG&G ORTEC Fast pulse counting electronics for photon counting, TOF MS, ion counting, LIDAR EG&G Signal Recovery Lock in amplifiers, preamps, signal averagers Ocean Optics, Inc. Fiber optic spectrometers and accessories ORIEL Instruments, Inc. Complete range of optical instrumentation, monochromators and spectrographs, light sources and accessories Ernst Leybold who founded the company in cologne in 1850 expanded the operation's product line four years later to include apparatus for the fields of physics, pharmacology and chemistry. A new era began for the company in 1906. This year marked the start of the collaboration with Prof. Dr. Wolfgang Geade, Professor of Physics at the College of Engineering in Karlsrhuhe Germany, Geade's inventions include the molecular air pump (1911) and the diffusion pump (1913). In 1851 Wilhelm Carl Heraeus took over the "Einhorn Apotheke" Pharmacy in Hanau. In 1916 vacuum-engineering pioneer Dr. Wilhelm Rohn, succeeded in melting metals under vacuum conditions. Fifteen years later, Heraeus accomplished the vapour deposition of metals onto glass. This was the first milestone on to the road of today's vacuum coating technology. The Hanau based company became an independent company, Heraeus Hochvakuum GmbH, in 1966. MATERIALS CHARACTERISATION • • • • • Andor Technology Limited Low cost Benchtop RAMAN spectrometer EG&G Princeton Applied Research Product leader in electrochemical instruments and accessories Ocean Optics, Inc. New low cost RAMAN spectrometer based on their miniature spectrometer technology ORIEL Instruments, Inc. New modular low cost FTIR system Uniscan Instruments Ltd. Optical Surface Profiler, SRET, Scanning Kelvin Probe; unique series of instruments for surface evaluation GTL maintains a distribution and service facility in Mississauga and sales offices in Ottawa and Vancouver. Feel free to contact GTL at the following: Gamble Technologies Limited Mississauga Distribution Facility 6535 Millcreek Drive, Unit #58, Mississauga, ON L5N 2M2 Tel (905) 812-9200; Fax 812-9203 Toll Free +1 800 268-2735 Ottawa Tel (613) 599-1101; fax 599-7897 Vancouver Tel (604) 929-3881 ; fax 929-5717 Email [email protected] The two firms from Cologne and Hanau merged in 1967 into what was then called Leybold-Heraeus GmbH. This merger combined the almost complete program of Vacuum Technology with the Vacuum Process Engineering, providing Leybold-Heraeus with a leading international position in these fields. Recently in 1994 Leybold was purchased by the Swiss based Holding organization of Oerlikon-Buhrle (OBH), who already owned the Balzers organization. Today the two companies form a Division called Balzers and Leybold Holding. This organization with sales over 1 Billion Swiss Franks employs over 5000 employees and has production facilities and sales offices in almost every country in the world. Leybold Canada was started as a Distributor in 1977 and has since then supplied the physics community in Canada with High and Ultra-High Vacuum Pumping Systems and components. Leybold Canada has grown to include a full time service center and warehouse in Mississauga, Ontario. The center includes customer support personnel, service personnel and sales engineers. The vacuum technology product line includes Turbomolecular Pumps, Rotary Vane Pumps, Roots Blowers, the Transpector Residual Gas Analyzer, Vacuum Gauges, portable Helium Leak Detectors, thin Film Controllers and crystal sensors. As well, vacuum LA PHYSIQUE AU CANADA juillet à août, 1998 245 coating chambers, utilizing Leybold patented coating technology, are available for a wide variety of substrates. Leybold Canada Inc. is ISO 9002 Registered and is strongly committed to superior customer satisfaction. Executive Contacts: Mr. R. Albers, President Mr. N. Brokenshire, P. Eng., Sales Manager commitment to research and development because of the potential for future commercial opportunities. OCI is now one of few world wide makers of LEED-AES spectrometers, miniature electron and ion sputter guns. This instrumentation is used in the development of the new materials for microelectronic devices and thin film coatings. If you find interest in some of this field please call and take advantage of our standard or custom design, service and production capabilities. In the past, many customers have communicated their needs to us and we responded with either adaptations or development of new products. Together with our collaborating companies in USA, Germany and Japan we offer most comprehensive solution for your surface related requirements. The company is looking for more customers in the world market and for stronger ties with local research and industrial organizations. O C I VACUUM MICROENGINEERING Primary Area of Expertise • Design and manufacture of low-energy-electron-diffraction (LEED) and Auger electron spectroscopy analyzers • Design and manufacture of miniature ion and electron sources • Design and manufacture of complete system for thin film composition testing • Luminescent and indium-tin-oxide coatings • Design and computer modelling of charged particles in electric and magnetic fields • Design and computer modelling of high vacuum systems • Laboratory Testing Capabilities: - gas emission analysis by quadrupole mass spectrometry - surface elemental composition by Auger/LEED spectroscopy - helium leak test for welded enclosures Description of Products or Services OCI Vacuum Microengineering has been grown out of research being done at a number of universities in Europe, Canada and the U . S . . The company has a very strong Facility: 2500 sq. f. industrial facility equipped with: CAD station based on Pentium(TM) PC computers, data aquisition-processing PC computer system, ultra high vacuum pumping systems and chambers, helium leak detection system, clean room, chemical processing room, electronics assembly and testing, mini-machine shop. Additional Areas of Interest: Vacuum Technology Modern vacuum technology is applicable to many industrial and scientific field for the process development, device manufacturing or materials/device testing. Our company has a wide and strong experience in this field to start a new development to solve the problems for the very specific application. 340 Saskatoon St., London, On Voice: (519) 457-0878 Fax: (519) 457-0837 E-mail: [email protected] Web: www.ocivm.com N5W 4R3 Key Personnel: Dr. Jozef G. Ociepa, President N E W S FROM CORPORATE MEMBERS INSTITUT NATIONAL D'OPTIQUE INO (Institut national d'optique) is pleased to report outstanding results for fiscal 1997-98. Outside revenues rose 39% compared to last year mainly as a result of exceptional growth in sales of specialty optical fibers, products incorporating optical fibers and laser illuminators. INO's rate of self-financing jumped 10% over last year and now stands at 68%. Increased activity spurred the creation of 25 new jobs in 1997-98, mainly for researchers and technologists. 246 PHYSICS IN CANADA July/August 1998 With experts predicting a surge in the photonics market over the next five years, INO has unveiled plans for the expansion of its facilities located in the Quebec Metro High Tech Park. Construction of the 6000 sq. meter addition is scheduled to begin next year. This project will enable INO to double its research space, create one hundred new jobs and increase its revenues from sales and contracts to $33 million by 2003. Physics in Canada - Vol. 54, No. 4 July/August 1998 La Physique au Canada - Vol. 54, N° 4 1998 juillet/août FEATURING: Stratospheric O z o n e and the Internet: by A. Fergusson A n Instructional Strategy: The Physics of W a v e Pools by D. M a t h e w s o n 1997 CAP Undergraduate Prize Examination 1997 CAP Income Survey / Sondage de l'ACP sur les revenus de 1997 b y R.E. G r e e n CORPORATE A N D INSTITUTIONAL MEMBERS CORPORATE MEMBERS / MEMBRES CORPORATIFS as at 1998 J u n e 30 / j u s q u ' à le 30 juin 1998 The Corporate Members of the Canadian Association of Physicists are a group of corporations, laboratories, and institutions who, through their membership, support the educational activities of the Association. Les membres corporatifs de l'Association canadienne des physiciens et physiciennes sont un groupe de corporations, d<; laboratoires ou d'institutions qui supportent financièrement les activités éducatives de l'Association. The entire proceeds of corporate membership contributions are paid into the CAP Educational Trust Fund and are tax deductible. Les revenus de leurs contributions déductibles aux fins d'impôt sont entièrement versés au Fonds Educatif de l'ACP. Atlantic Nuclear Services Ltd. Atomic Energy of Canada Ltd. Edwards High Vacuum Canada Gamble Technologies Limited Gennum Corporation Harvard Apparatus Canada Institut national d'optique Kurt J. Lesker Canada Inc. Lighting Sciences Canada Inc. Lumonics Inc. The Canadian Association of Physicists cordially invites interested corporations and institutions to make application for Corporate membership and will welcome the inquiries addressed to the Executive Director. MPB Technologies Inc. Newport Instruments Canada Corp. OCI Vacuum Microengineering Inc. Optech Incorporated Varian Canada Inc. L'Association canadienne des physiciens et physiciennes invite cordialement corporations et institutions à faire partie des membres corporatifs. Renseignements auprès de la directrice exécutive. CANADIAN ASSOCIATION OF PHYSICISTS / ASSOCIATION CANADIENNE DES PHYSICIENS ET PHYSICIENNES Bur«Suite 112, Imm. McDonald Building 150 rue Louis Pasteur Ave., Ottawa, Ontario K1N 6N5 Phone: (613) 562-5614 or Fax: (613) 562-5615 E-mail: [email protected] ; Website: http://www.cap.ca INSTITUTIONAL MEMBERS / MEMBRES INSTITUTIONEL ( Physics Departments / Départements de physique ) as at 1998 June 30 / j u s q u ' à le 30 juin 1998 Acadia University Bishop's University Brandon University Brock University Carleton University CEGEP Beauce-Appalaches CEGEP Francois-Xavier-Garneau Collège Montmorency Concordia University Dalhousie University École Polytechnique Laurentian University McGill University McMaster University Memorial Univ. of Newfoundland Mount Allison University 248 PHYSICS IN CANADA Okanagan University College Queen's University Royal Military College Saint Mary's University Simon Fraser University St. Francis Xavier University Trent University University of Alberta University of British Columbia University of Calgary University of Guelph Université Laval University of Lethbridge University of Manitoba Université de Montréal University of New Brunswick July/August 1 9 9 8 University of Northern B.C. University of Ottawa University of Prince Edward Island Université du Québec à Montréal Univ. du Québec à Trois-Rivières University of Regina Univ. of Saskatchewan (& Eng. Phys es) Université de Sherbrooke University of Toronto University of Victoria University of Waterloo University of Western Ontario University of Windsor University of Winnipeg Wilfrid Laurier University York University L A PHYSIQUE ET L ' É D U C A T I O N (STRATOSPHERIC O Z O N E . . . ) STRATOSPHERIC OZONE SCIENCE A N D THE INTERNET by Angus Fergusson the severity of ozone depletion and UV radiation on their health, on wildlife and on the ecosystems around hroughout our lives scientists, them. It is well known that people receive 70% of their environmentalists, and policy-makers have damaging exposure before the age of 18. It will be been concerned about stratospheric ozone through this knowledge that teachers, parents and depletion and are working on a global students can take appropriate precautions to protect solution to the problem. At the same time, computer themselves and ensure the survival of the various technology is leaping ahead. Through exploring the ecosystems. Since the solution Internet, students can learn to ozone depletion will take interesting and relevant facts decades, it will be u p to about ozone depletion, Over the past fifteen years, industrial future generations to ensure explore exciting sites created chemicals like chlorofluorocarbons, that the science and the by scientists doing the halons, and methyl bromide have international agreements and research, and analyze data tipped the delicate balance in the controls are improved so that and graphs to complete their upper atmosphere and caused the ozone layer does indeed projects. stratospheric ozone to be destroyed recover. faster than it can be naturally made. This article will look at some THE PROBLEM of the resources available on the Internet and activities to Back in the 1970s, stratospheric ozone depletion was teach students about ozone depletion and UV of interest only to a small group of scientists who radiation issues. were concerned about the vulnerability of the ozone layer to supersonic aircraft flights. In 1974 two WHY TEACH ABOUT STRATOSPHERIC O Z O N E scientists, Sherwood Rowland and Mario Molina, DEPLETION? showed that inert chemicals used as refrigerants and as propellants in spray cans could be transported into Over the past fifteen years, industrial chemicals like the strato-sphere where sunlight would result in the chlorofluorocarbons, halons, and methyl bromide release of chlorine. The free chlorine atom would then have tipped the delicate balance in the upper break down the ozone molecules and through a series atmosphere and caused stratospheric ozone to be of reactions the single chlorine atom would remove destroyed faster than it can be naturally made. This about 100,000 molecules in its lifetime. The inert has led to a thinner ozone layer with the result that chemical was known as chlorofluorocarbon (CFC). It ultraviolet radiation has increased at the surface. is now known that bromine from halons used in fire While the natural levels of ultraviolet radiation do extinguishers and from methyl bromide used as a pose a threat to h u m a n health, the increase in UV fumigant in agriculture will also deplete the ozone radiation poses an additional threat to h u m a n and layer with an even greater ozone-destructive effect. animal health, and to ecosystems. T Since this threat will be with us into the next century, the ozone depletion issue provides an opportunity to teach students how to deal with a global environmental problem and how they can manage environmental problems in the future. In addition, to protect themselves and their environment, they must understand Angus Fergusson is a Science Advisor on Ozone/UV-B at Environment Canada, Downsview Ontario LA PHYSIQUE AU CANADA juillet à août, 1998 249 PHYSICS A N D E D U C A T I O N (STRATOSPHERIC O Z O N E . ..) Since CFCs are inert chemicals, they are very stable and have an atmospheric lifetime of 50 to 100 years or more. Because CFCs are inert, there are no processes in the lower atmosphere to remove them. Thus, to be removed from the atmosphere, CFCs must be photodissociated in the stratosphere and then carried by the air currents into the troposphere where they can react with other chemicals and be removed. In Canada, the annual average ozone values have declined by about 6% from the pre-1980 means. Ozone depletion is greatest over the Arctic and less over the mid-latitudes. Depletion reaches a maximum in the springtime and is least in the fall. The total amount of UV radiation received at the ground is determined by the solar elevation, the amount of ozone in the atmosphere, the cloudiness in the sky and to a lessor extent pollution. The higher the sun is in the sky, the more intense are the rays because they travel through a shorter path in the atmosphere. In the summer months, this results in the most intense It was the discovery of the ozone hole in the Antarctic in 1985 that moved the world to control substances that contain ozone-depleting chlorine and bromine. In that year, the ozone hole covered about 10 million 400 T O T A L O Z O N E O V E R 11 N O R T H MID-LATITUDE SITES A N D 390 - OVER CANADA (1-year smoothing) 380 - 370 - a 363 DU 360 - N o 350 340 330 320 A V E R A G E F R O M 11 S I T E S B E T W E E N 4 0 A N D 71 D E G R E E S N O R T H 5 - SITE CANADIAN AVERAGE P R E - 1980 A V E R A G E O F T H E 11 S I T E S P R E - 1980 A V E R A G E O F 5 C A N A D I A N S I T E S 310 1960 1965 1970 1975 1980 1985 1990 1995 YEAR International Sites: Barrow. Belsk, Bismark, Boulder. Caribou, Fairtanks, Hradec Kralove, Leiwick, Saporo, Uccle, Vigna Dl Valle. square kilometres. In comparison, this past spring in the Antarctic ozone values depleted to about 60% of their pre-1970 normal values and the "hole" now covers about 24 million square kilometres. Meanwhile in the last two years, scientists have discovered that severe ozone depletion has also occurred over the Arctic. Since the Arctic has naturally about one and a half times more stratospheric ozone, the depletion is not as severe as in the Antarctic. 250 PHYSICS IN CANADA J u l y / A u g u s t 1998 UV radiation occurring just at solar noon. A decline in the total ozone over a particular location will result in an increase in UV radiation. To put the role of ozone in perspective, the 6 percent decrease in ozone over southern Canada has led to a 7 percent increase in UV radiation. Finally, thick clouds do reduce the amount of UV radiation reaching the ground by reflecting it back into space. However, on days with scattered clouds the UV radiation received at the ground can actually be increased due to reflection from the clouds to the ground. L A PHYSIQUE ET L ' É D U C A T I O N TEACHING O Z O N E A N D UV- B SCIENCE (STRATOSPHERIC O Z O N E . . . ) the stratosphere may become colder. This would result in more ozone depletion in the polar regions in the springtime. Although students may not understand these complex cycles or interactions, the teachers can convey to the students the related consequences and give them a sense that all these issues are interconnected. Stratospheric ozone depletion provides an excellent opportunity to teach about the atmospheric system, our impact on that system, and the decisions that everyone must make about that system — personally, nationally and internationally — to ensure people's welfare and that of the environment. When teaching students about the atmosphere, a good place to start is with the evolution of the ozone layer. Four billion years ago, when the earth was first formed, there was no oxygen or ozone layer. Oxygen formed about 2 billion years later, after life formed in the ocean and provided oxygen to the atmosphere. Some oxygen was then broken d o w n by the ultraviolet radiation to produce ozone in the stratosphere. It was only after the ozone layer was formed that life was then able to evolve on the continents. Thus no life on land could evolve and persist without the ozone layer. The ozone layer screens out about 90 percent of the UV radiation reaching the earth. Students should also be aware that the discovery of chlorofluorocarbons by a DuPont chemist named Thomas Midgely, Jr. in 1928 was considered a significant discovery since this gas had the very desirable characteristics of low toxicity, low flammability and favourable thermodynamic properties. It was not until the 1970s that scientific evidence showed a possible link to ozone depletion and it took until the mid 1980s for international attitudes to change and for action to control these substance to begin. This is a good example of where a human's inventions had good intentions, but they also had serious implications on the environment. What early scientists didn't understand when CFCs were invented was that the chemicals would gradually rise in the atmosphere and become detectable everywhere. Since CFCs are heavier than air, scientists had not considered that they would be carried u p into the stratosphere by the winds and updrafts. Scientists have also only recently begun to understand that ozone depletion affects other cycles or systems in the atmosphere. For example, ozone depletion and climatic change are linked in many complex ways. CFCs not only deplete the ozone layer, but also enhance the greenhouse effect. It is possible that as more heat is trapped near the earth's surface, Finally, teachers may want to relate to the students the level of international cooperation that has taken place amongst industry, government, and general public for the protection of the ozone layer. The major global effort has been through the Montreal Protocol. This has not been an easy process since all stakeholders have their wants, needs and ambitions. THE INTERNET There are many sources of information on stratospheric ozone depletion which a student can explore as part of a learning experience or as a project. On the Internet, there are many good sites, some of which are listed below. Many of these sites have links to external sites. Government Sites: These sites provide a variety of information ranging from basic public information, educational information, to scientific data. The data on the Canadian Meteorological Centre can be used by students w h o wish information on daily or seasonal ozone values. The Experimental Studies Division of Environment Canada provides graphic information on its website for 12 Canadian ozone stations. This division also runs, for the World Meteorological Organization and the world scientific community, the World Ozone and Ultraviolet Radiation Data Centre. This website contains ozone and UV data from more than 150 stations around the world. Greenlane http://www.ec.gc.ca/ozone Canadian Meteorological Centre http://www.cmc.ec.gc.ca/cmc/htmls/a-ozone.html Experimental Studies Division http://exp-studies.tor.ec.gc.ca World Ozone and Ultraviolet Radiation Data Centre http://www.tor.ec.gc.ca/woudc/woudc.htm Environment Protection Agency of the U.S. http://www.epa.gov/ozone LA PHYSIQUE AU CANADA juillet à août, 1998 251 PHYSICS A N D E D U C A T I O N (STRATOSPHERIC O Z O N E . ..) clearinghouse of information related to the ozone and the challenges faced in its preservation. Government Scientific Sites: NASA Goddard Space Flight Center has some very good images from the Total Ozone Mapping Spectrometer (TOMS) instrument on the Nimbus-7 satellite. The ozone hole in the Antarctic was discovered by the British Antarctic Survey. They have interesting bulletins and data about ozone at Halley, Rothera and Vernadsky/Faraday stations. Ozone soundings from the Neumayer and South Pole Stations can be found on the Alfred Wegener Institute (AWI) website. Earth Probe TOMS Data and Images http://jwocky.gsfc.nasa.gov/eptoms/ep.html British Antarctic Survey http://www.nerc-bas.ac.uk/public/icd/jds/ozone Alfred Wegener Institute http://www.awi-bremerhaven.de/MET/ Neumayer/ozone.html Environmental organization: Ozone Action, based in Washington, DC, is a nonprofit public interest organization focused on global climate change and stratospheric ozone depletion Ozone Action http://www.ozone.org Educational Sites: A graphing exercise is provided at the Exploratorium Site that uses data from NASA images as well as images from the Neumayer Antarctic Station. The Usenet FAQ sites provides information on ozone depletion as well as links to many other sites. Graphing Stratospheric Ozone http://www .exploratorium ,edu/leaming_studio/ ...ozone/graphing.html Usenet FAQs http://www.cis.ohio-state.edu/hypertext/faq/usenet/ ...ozone-depletion/top.html United Nations Sites: The World Meteorological Organization (WMO) site allows access to the W M O Antarctic ozone bulletins — published monthly during the austral spring — and the northern hemisphere ozone maps. The United Nations Environment Programme (UNEP) provides a 252 PHYSICS IN CANADA July/August 1998 WMO http://www.wmo.ch/web/arep/arep-home.html UNEP http://www.unep.org/unep/secretar.'ozone/home.htm Students should be aware of the possible impacts increased UV-B has on health and on ecosystems. This is an area that is suited for a science project where a student can do a literature review in the library, on the Internet, or a project on an ecosystem. For example, a student from British Columbia did a project on the effects of UV radiation on terrestrial plants and phytoplankton. The student discovered and learned about some very important processes which take place between the world's ecosystems and environmental stressors. In particular, she learned that there is a very fragile equilibrium that exists between an ecosystem and its environment. Changes in UV radiation, climate, as well as other stressors, can upset that balance. A good Internet site to surf on UV impacts is: http://www.islandnet.com/~see/uvb.htm WHERE D O WE G O FROM HERE? The ozone depletion issue presents a unique opportunity for students to learn about atmospheric science and how this issue will impact on their lives and the environment around them. It will be through this knowledge that they can ensure that their health is protected, ozone depletion is stopped, and that the lessons learned can be used in solutions to future environment problems. The Internet is a relatively new tool which allows students to explore, investigate, analyze and have fun, all the while gaining knowledge and skills. The ozone depletion problem is not solved yet. Although the international community, in the Montreal Protocol, has agreed to controls that will limit substances that deplete the ozone layer, it will take at least until the middle of the next century for the natural balance to be established again. No one can be sure, at this point, that this will occur since there are processes in the atmosphere that we don't fully understand and controls that are not fully implemented. L A PHYSIQUE ET L'ÉDUCATION ( A N INSTRUCTIONAL STRATEGY...) A N INSTRUCTIONAL STRATEGY: THE PHYSICS OF W A V E POOLS by D. Mathewson A t the end of a unit of instruction on waves, I As an activity done together by a group of people, the take my high school classes to a local wave excursion is also a 'ritual' that fosters teamwork and a pool. Using metre sticks and stopwatches the sense of comradery amongst the students. This is not a students take measurements, perform trivial matter, since recent educational research111 shows calculations and answer that rich interactive learning conceptual questions relating environments significantly to their study of waves. A As an activity done together by a enhance learning. The same typical exercise is included educational research also group of people, the excursion is below. There are many good indicates that positive attitudes also a 'ritual' that fosters teamwork reasons for doing an activity translate into better learning, and like this. Most importantly it and a sense of comaraderie there is nothing like a physics establishes an environment class at the wave pool to boost amongst the students. within which students can the enthusiasm of your class. Of relate what they have learned course this activity comes at some expense to the student and at the expense of a lost to practical experience. Only a few students will have day of classroom instruction. Care must also be taken to previously been to the wave pool and very few will have structure the time so that the outing is seen as 'physics thought about the physics of the waves. The field trip time' and not 'play time'. In general, however, these thus provides a vital common experience to which all difficulties stack up small when compared with the students can apply their nascent physics knowledge. potential gains. WAVE PROPERTIES A. DATA: deep end With the w a v e generator at l o w p o w e r , use a metre stick and s t o p w a t c h to measure the following: wavelength: time for w a v e to travel 5 metres: period : amplitude(A): width of pool(w): B. CALCULATIONS: 1. Find the speed of the w a v e s in d e e p water based o n the time to travel 5 m. T o p v i e w of 2. Calculate the w a v e frequency w a v e pool 3. Calculate the w a v e speed using the w a v e equation and compare with #1. 4. U s e the formula for w a v e p o w e r P = B w v A 3 f 2 (derived from Giancoli 3rd e d ' n 11-31 p g 292): B = constant = 18000 k g / m w = w a v e width (m) v = w a v e speed ( m / s ) A = w a v e amplitude (m) f = w a v e frequency ( 1 / s ) to find the p o w e r produced by the w a v e generator. 5. Estimate the w o r k / e n e r g y c o n s u m e d in running the w a v e pool at l o w p o w e r for o n e hour. C. CONCEPT QUESTIONS: 1. 2. 3. 4. Draw What What What a picture of a w a v e and label the w a v e l e n g t h . d o e s frequency mean? d o e s period mean? factors should w a v e p o w e r d e p e n d on? I have recently had some experience with Science instruction at the Junior grades and have found that, with some adaptation, such outings can still work wonderfully. I submit to you that the same is probably true to second and third year undergraduate courses... and maybe even beyond. Let me end this discussion then with two questions: 1. Is there something you could design for your students to do/build/create in the space of an hour that would enhance their understanding of your course? 2. Would it be worth sacrificing one lecture to do such an activity? REFERENCES 1. Making Connections: Caine R.N, and G. Association for Supervision and Curriculum Development Publications: Alexandria, Virginia 1991. D. M a t h e w s o n teaches physics at the Steveston Secondary S c h o o l / K w a n t i e n University College, Richmond, British Columbia. LA PHYSIQUE AU CANADA juillet à août, 1998 253 1997 UNIVERSITY PRIZE EXAMINATION 1 9 9 7 C A P UNDERGRADUATE PRIZE EXAMINATION CONCOURS DU PRIX UNIVERSITAIRE DE L ' A C P 1 9 9 7 1. Capacitors with dielectrics 2. C o n d e n s a t e u r s avec diélectriques A I I ' *; • : . ; . 111 •.'. •.-.. ** •.'. •.-. ••iSIlM illSiSli IllIillilB I •' us ' , • % ; ; ; % ; . I . % ; . ; % ; \ ; . *2 I Figure 1 Figure 2 In Fig. 1, A, is the area of the dielectric with dielectric constant A 2 is the area of the dielectric K 2 , a n d x is the thickness of the dielectric. In Fig. 2, A is the area of the dielectric, x, is the thickness of the dielectric K„ a n d x2 is the thickness of the dielectric K 2 . D a n s la figure 1, A t représente l'aire d u diélectrique dont la constante diélectrique est K,, A 2 représente l'aire d u diélectrique K2 et x est l'épaisseur c o m m u n e des deux diélectriques. Dans las figure 2, A est l'aire et Xj l'épaisseur d u diélectrique K 2 tandis q u e x2 est l'épaisseur d u diélectrique K2. (a) (a) (b) (c) Find the capacitance for the a r r a n g e m e n t s h o w n in Fig. 1. Find the capacitance for the a r r a n g e m e n t s h o w n in Fig. 2. If a charge Q is applied to the capacitor s h o w n in Fig. 1, w h a t is the resulting energy density in the regions w i t h dielectric constant Kj a n d K2, respectively? (Take 2. (c) Trouver la capacitance de la configuration illustrée par la figure 1. Trouver la capacitance d e la configuration illustrée par la figure 2. Si u n e charge Q est appliquée au condensateur de la figure 1, quelles sont les densités d'énergie qui en résultent d a n s les régions avec constantes diélectriques K, et K2 respectivement? (Prendre x^ + x2 = x, et Aj + A 2 = A.) 2. Plasmons d'interface (b) + x2 = x, a n d A, + A 2 = A.) Interface plasmons. We consider the plane 2 = 0 b e t w e e n metal 1 w i t h z > 0 a n d metal 2 with 2 = 0. Metal 1 has bulk plasma frequency w pl ; Metal 2 has bulk p l a s m a f r e q u e n c y œ p2 . A solution of Laplace's equation V2 (J> = 0 in the plasma is cf>1(jtr/2) = A cos kxe*2 for 2 > 0 a n d <j>2(x,2) = A cos kzwkz for z < 0. O n considère le plan 2 = 0 séparant le métal 1 situé dans z > 0 d u métal 2 situé d a n s z = 0. Le métal 1 a comme fréquence plasmique volumétrique copl; et le métal 2 a c o m m e fréquence plasmique volumétrique wp2. Une solution de l'équation de Laplace V2 <> | = 0 d a n s le plasma est: (j)j ix,z) = A cos kxë*2 p o u r z > 0 et 4>2(x,z) = A cos kzvf* p o u r 2 < 0. (a) (b) (a) Calculate Ex a n d E z o n each side of the b o u n d a r y . Show that Ex is continous across the b o u n d a r y . (b) (c) 254 PHYSICS IN CANADA July/August 1998 Calculer Ex et Ez de chaque côté d u plan limite séparant les deux métaux. Montrer q u e Ex est continu à travers le plan limite. Finalement, en faisant appel à la continuité de la composante z de D au plan limite et au fait q u e CONCOURS DU PRIX UNIVERSITAIRE 1 9 9 7 (c) Next, f r o m the continuity of the z c o m p o n e n t of D at CO the b o u n d a r y , a n d the fact that £ j (co) = 1 co p> p—, > for , p o u r i = 1 et 2, montrer que CO (0 ®=V ( C Ù pi + i = 1 and 2, s h o w that co = y (co ^ + co p 2 ) / 2 . 3. In this problem, a s s u m e it is k n o w n that the energy density u (in J / m 3 ) for blackbody radiation is a function of the temperature T only, and also that the pressure p = u / 3 . The problem is to d e t e r m i n e h o w u d e p e n d s on T. This can be done as follows. Let the radiant energy in a cylinder be carried t h r o u g h a C a r n o t cycle, as s h o w n in the diagram, consisting of an isothermal expansion at t e m p e r a t u r e T, an infinitesimal adiabatic expansion in w h i c h the t e m p e r a t u r e drops to T - dT, an isothermal compression at T - dT, and an infinitesimal adiabatic compression to the original state. T T (voir le figure d a n s le n u m é r o 3 à gauche) T-dT (c) (d) p2 ) 7 2 • 3. Dans ce problème, on s u p p o s e connu le fait que la densité d'énergie u (mesurée en J / m 3 ) d u rayonnement de corps noir est u n e fonction de la température T seulement. O n s u p p o s e connu aussi le fait q u e la pression p = u / 3 . Le problème est de déterminer c o m m e n t u dépend de T. Ceci peut être fait de la manière suivante. On permet à l'énergie d u r a y o n n e m e n t confiné d a n s u n cylindre d'exécuter un cycle de Carnot tel qu'illustré d a n s le d i a g r a m m e cidessous. Ce cycle consiste d ' u n e expansion isothermale à la température T, d ' u n e expansion adiabatique infinitésimale d a n s laquelle la température baisse p o u r atteindre T dT, d ' u n e compression isothermale à la température T - dT et d ' u n e compression adiabatique infinitésimale menant à l'état tel q u ' a u début d u cycle. V (a) (b) 05 (a) (b) V Plot the cycle in the p - V plane. Calculate the w o r k d o n e by the system d u r i n g the cycle. Calculate the heat flowing into the system d u r i n g the cycle. Show that the energy density u is proportional to T4 by considering the efficiency of the cycle. 4. The magnetic m o m e n t of an ion of spin J can have (2J+1) orientations with respect to the external field B. The components of the m o m e n t along B can be Jm, (J-l)m, (J2)m,... (-J+l)m, -Jm. C o n s i d e r a p a r a m a g n e t i c system of N distinguishable lattice sites, each occupied by one ion of spin J. (The ions are identical, except for being "nailed d o w n " , one to each site.) The p a r a m a g n e t i c system is in equilibrium at t e m p e r a t u r e x = kT, w h e r e k is the Boltzmann constant. S h o w that the magnetic m o m e n t M of the system is given by M = Nm coth fr H J +— mB — coth 2 1 mB 5. A point m a s s m, rests alone in space, while a distant second point mass m2 m o v e s with constant small velocity v0. In the absence of gravity, m2 w o u l d pass by m^ with impact parameter (distance of closest approach) b0. Taking gravity into account, (c) (d) Dessiner le cycle d a n s le plan p - V. Calculer le travail effectué par le système d u r a n t le cycle. Calculer la quantité de chaleur passant dans le système d u r a n t le cycle. Montrer q u e la densité d'énergie est proportionnelle à T4 par considération de l'efficacité d u cycle. 4. Le m o m e n t magnétique d ' u n ion de spin J peut avoir (2J+1) orientations différentes par rapport à u n champs extérieur B. La c o m p o s a n t e d u m o m e n t dans la direction de B peut p r e n d r e u n e des valeurs suivantes: Jm, (J-l)m, (J2)m,....(-J+l)m, -Jm. O n considère u n système paramagnétique c o m p r e n a n t N positions d a n s u n réseau, toutes distinctes et chacune occupée par u n ion de spin J. (Les ions sont identiques excepté qu'ils sont fixés aux positions qu'ils occupent d a n s le réseau, u n ion par position). Le système p a r a m a g n é t i q u e est en équilibre à la température x = kT où k est la constante de Boltzmann. Montrer que le m o m e n t magnétique M d u système est d o n n é par: M = Nm coth J+— 2J MB -—coth 2 1 MB 2 T 5. Une masse ponctuelle m, est a u repos dans l'espace tandis, qu'à distance, u n e deuxième masse ponctuelle m2 se m e u t avec u n e petite vitess v0 qui est de plus constante. Dans l'absence de force gravitationnelle, m2 croiserait m, avec u n paramètre d'impact (défini c o m m e la distance m i n i m u m les séparant) de b0. P r e n d r e la force gravitationnelle en considération et LA P H Y S I Q U E AU C A N A D A juillet à août, 1998 255 1 9 9 7 UNIVERSITY PRIZE EXAMINATION (a) (b) Find the energy a n d the a n g u l a r m o m e n t u m in the center of m a s s frame. Find the actual impact p a r a m e t e r b in terms of bg, v^ G, and the t w o masses. (a) (b) Trouver l'énergie et le m o m e n t angulaire d a n s le système de référence de centre d e masse. Trouver le paramètre d'impact actuel b en fonction de b0, vy G et les deux masses. 6. A rare m o d e of inverse P-decay involves resonant capture of an electron antineutrino vc (assumed massless) by a h y d r o g e n atom, p r o d u c i n g only a recoil neutron. If the h y d r o g e n a t o m is in its g r o u n d state a n d at rest, w h a t w o u l d be the s p e e d of the recoiling n e u t r o n ? (mH = 1.007825 u, mn = 1.008665 u, 1 u = 931.502 MeV) 6. Un m o d e rare appelée p -décomposition inverse implique la capture en résonance d ' u n antineutrino électronique vc (supposé de masse nulle) par u n atome d ' h y d r o g è n e et la production d ' u n seul neutron de recul. Si l'atome d ' h y d r o g è n e est d a n s son niveau d'énergie le plus bas (niveau fondamental) et aussi au repos, qu'elle sera la vitesse d u neutron produit? (mH = 1.007825 u, mn = 1.008665 u, 1 u = 931.502 MeV) 7. The existence of n e u t r i n o masses, a n d of oscillations between the three generations of neutrinos, remains an intriguing possibility. A toy model, w h i c h exhibits v a c u u m oscillations b e t w e e n t w o m a s s eigenstates, has the simple mass Hamiltonian 7. La possibilité q u e les neutrinos soient massifs et qu'ils puissent osciller entre les trois générations de neutrinos entrigue plusieurs. Un modèle-jouet qui illustre les oscillations d u vide entre deux états propres de l'opérateur de masse, a p o u r Hamiltonien de masse l'expression simple suivante: H= ( M m' m M, c 2 , w h e r e M £ m, H= and and the t w o physical states represented by are fM m^ v m MJ c , ou M s m, Les deux états physiques représentés par V linear combinations of the m a s s eigenstates. (a) (b) Find the eigenvalues of H, a n d the corresponding m a s s eigenvectors. By solving the time d e p e n d e n t Schrôdinger equation ihdtfit) = HY(£), find the shortest time T necessary for a system, initially in the state represented by sont et .0) |T 10. des combinaisons linéaires des états propres de l'opérateur d e masse. (a) Trouver les valeurs p r o p r e s de H et les états propres correspondants. (b) Résoudre l'équation de Schrôdinger qui d é p e n d du temps iftVF(f) = H'F(f), et trouver le temps x le plus court nécessaire p o u r q u ' u n système initialement d a n s , to l'état représenté par r soit transformé transform completely into the state represented by complètement en l'état représenté par '5(c) If Me 2 = 17 keV, w h a t w o u l d be the m i n i m u m value of T in seconds? 8. O n e example of the M o s s b a u e r effect is given by the decay of the 57 Co nucleus to 57 Fe by electron capture w h e r e the final nucleus (of m a s s M) subsequently returns to the g r o u n d state by emitting a photon. The energy of that photon d e p e n d s on the total energy available, 14.4 keV in this case a n d labelled as E„, a n d u p o n the division of energy between the p h o t o n a n d the recoiling nucleus. The heavier the nucleus, the less energy is required to satisfy m o m e n t u m conservation, a n d the smaller is the possible 256 P H Y S I C S IN C A N A D A July/August 1998 (c) \) Si Mc2 = 17 keV, quelle est la valeur de t en secondes? 8. Un example de l'effet Mossbauer est d o n n é par la décomposition d u n o y a u 57Co en 57 Fe résultant de la capture d ' u n électron. Le noyau final (de masse M) retourne s u b s é q u e m m e n t à l'état f o n d a m e n t a l par l'émission d ' u n photon. L'énergie de ce p h o t o n d é p e n d de l'énergie totale disponible, énergie notée £_ et qui est de 14.4 keV d a n s notre cas, et aussi de la partition de cette énergie entre le photon et le neutron de recul. Le plus lourd le noyau est, le moins d'énergie est nécessaire p o u r satisfaire la conservation de la quantité de m o u v e m e n t et le plus étroit devient le c h a m p s des énergies possibles d u photon émis. Si le noyau fait partie d ' u n crystal macroscopique, la masse de recul CONCOURS DU PRIX UNIVERSITAIRE 1997 spread of energies of the emitted p h o t o n . If the nucleus is part of a macroscopic crystal, then the recoiling mass can be very large a n d consequently the photon energy a p p r o a c h e s that of a monoenergetic, m o n o c h r o m a t i c source - hence the label E_, the energy a p h o t o n w o u l d have if recoiling f r o m an infinitely large mass, (a) Considering the emission of a p h o t o n f r o m one single 57 Fe nucleus, use non-relativistic a r g u m e n t s (justified as the velocity of the 20m recoil nucleus is small) applied to energy and m o m e n t u m conservation to calculate the difference b e t w e e n E_ a n d the actual energy Ey of the p h o t o n a n d s h o w that the following a p p r o x i m a t e relation holds: Source E„ - E y = (E„) 2 /(2MC 2 ) (b) (c) Deiecior Calculate the numerical value of the resulting frequency shift in the case of a p h o t o n recoiling against a large crystal of m a s s l g . Using this as a source of monoenergetic, monochromatic X rays, w h a t is the expected frequency shift w h e n the p h o t o n falls 20m u n d e r gravity? Take the original f r e q u e n c y as 3.48 x 1018 Hz. Constants: e = 1.6 x 10"19 C c = 3 x 10 8 m / s h = 6.63 x 10"34 J.s g = 9.8 m / s 2 peut devenir très g r a n d e et par conséquent l'énergie d u photon peut approcher celle d ' u n e source monoénergétique (monochromatique); ceci explique la notation £„, c'est l'énergie q u ' u n photon aurait s'il reculait après collision avec une masse infiniment grande. (a) Considérer l'émission d ' u n photon d ' u n seul noyau 57Fe. Utiliser des a r g u m e n t s nonrelativistes (justifiés par le fait que la vitesse d e recul d u n o y a u est petite) appliqués à la conservation d'énergie et de quantité de m o u v e m e n t p o u r calculer la différence entre E. et l'énergie actuelle Ey du photon. Montrer q u e la relation approximative suivante s'applique: E,-Ey~ ( E J 2 / (2Mc2) (b) Calculer la valeur n u m é r i q u e du décalage de fréquence qui en résulte dans le cas d ' u n p h o t o n reculant contre u n grand crystal de masse 1 g. (c) En utilisant ceci c o m m e u n e source de rayons X monénergétiques (monochromatiques), quel est le décalage de fréquence à laquelle on s'attend si le photon tombe d ' u n e distance de 20m sous l'influence de la gravité? Prendre la fréquence initiale comme étant de 3.48 x 1018 Hz. Constantes: e = 1.6 x 10"19 C h = 6.63 x 10 3 4 J.s 9. a) Material with a u n i f o r m resistivity p is f o r m e d into the c u r v e d shape s h o w n below. The t w o curved surfaces are circular with radii of a a n d b a n d the thickness of the slab is u n i f o r m a n d equal to t. Find an expression for the electrical resistance b e t w e e n the t w o faces fo the slab labelled A a n d B. b) If the material is a l u m i n u m with conductivity 0.355 x 10 8 (D.m)"1 a n d the object is m a c h i n e d such that a = 20 cm, b = 10 cm, a n d x = 1 cm, calculate numerically the resistance between those s a m e t w o surfaces. 10. - I î Explain briefly, in one p a r a g r a p h per topic, the physics principles involved in the operation of any FOUR of the following devices: i) a laser ii) an Electric Field Meter iii) a MOSFET transistor iv) a proportional counter (for m e a s u r i n g radiation fields) v) a thermocouple A 10. c = 3 x 10 8 m / s g = 9.8 m / s 2 a) O n a d o n n é à u n matériau de résistance uniforme p la forme courbée indiquée ci-dessous. Les deux surfaces courbées sont circulaires avec rayons a et b. L'épaisseur de la pièce est u n i f o r m e et égale à t. Obtenir u n e expression p o u r la résistance électrique entre les deux faces de la pièce marquées A et B. b) Si le matériau en question est l ' a l u m i n i u m don't la conductivité est 0.355 x 108 ( Q . m ^ e t la pièce est usinée de telle manière que a = 20 cm, b = 10 cm et t = 1 cm, calculer n u m é r i q u e m e n t la résistance entre ces deux mêmes faces Expliquer brièvement (un p a r a g r a p h e par sujet) les principles physiques impliqués dans l'opération de QUATRE appareils choisis p a r m i les suivants: i) u n laser ii) u n mètre à m e s u r e r le c h a m p s électrique iii) u n transistor MOSFET iv) u n c o m p t e u r proportionnel (pour mesurer les c h a m p s de rayonnement) v) u n thermocouple LA P H Y S I Q U E AU C A N A D A juillet à août, 1998 257 1 9 9 7 C A P INCOME SURVEY T H E C A P 1 9 9 7 I N C O M E S U R V E Y / S O N D A G E DE L ' A C P SUR LES REVENUS DE 1 9 9 7 BY R . E . G R E E N , R E T I R E D M E M B E R The CAP received 386 responses to the 1997 Income Survey. Trois cent quatre-vingt-six personnes ont répondu au Sondage de l'ACP sur les revenus de 1997. An overview of the salary income is provided by the histogram, which includes the 306 responses with a salary income. All respondents did not provide their bachelor year of graduation. For those who did, the responses are analyzed in the following 20 tables. Vous trouverez un aperçu des revenus de salaire dans histogramme, qui comprend les 306 répondants avec revenus d'un salaire. Les répondants n'ont pas tous donné l'année d'obtention de leur baccalauréat. Les réponses de ceux l'ayant donnée sont analysées dans les 20 tableaux suivants. Tables la to I d show the results for the four sources of income. There were 297 responses with salary income, 60 with pension income, 35 with consulting income, and 27 with scholarship income. The salary data are analyzed in more detail in the following 16 tables. Les tableaux la à Id montrent les résultats des quatre sources de revenus. Deux cent quatre-vingtdix-sept personnes ont déclaré avoir reçu des revenus d'un salaire, soixante d'une pension de retraite, trente-cinq de la consultation et vingt-sept des bourses d'études. Les données sur les salaires sont analysées en détails dans les seize tableaux suivants. Tables 2a to 2c show the results according to the qualifications of the respondents. There were 18 responses with a bachelor's degree, 36 with a master's degree, and 243 with a doctorate degree. Les tableaux 2a à 2c montrent les résultats d'après les qualifications des répondants. Dix-huit personnes ont répondu détenir un baccalauréat, trente-six une maîtrise et deux cent quarantetrois un doctorat. S •g 10 è tbd Tables 3a to 3e cover the areas of current employment. Histogram of 306 salaries There were 160 responses from the academic sector, 51 from government agencies, 46 from industry, 9 from graduate students, and 29 from other areas. Les tableaux 3a à 3e traitent des domaines d'emploi actuel. Cent Salaries ($K) soixante réponses ont été reçu processed in 1997 CAP Income Survey du secteur académique, cinquante et une d'agences gouvernementales, quarante-six d'industries, neuf d'étudiants diplômés et vingt-neuf d'autres domaines. 100 110 120 >125 Tables 4a to 4f cover the geographic region of employment. There were 24 responses from the Atlantic Provinces, 70 from Quebec, 97 from Ontario, 28 from the Prairie Provinces, 46 from British Columbia and the Territories, and 26 from outside Canada. Les tableaux 4a à 4f traitent de la région géographique d'emploi. Vingt-quatre personnes ont répondu des Provinces atlantiques, soixante-dix du Québec, quatre-vingt-dix-sept de l'Ontario, vingthuit des Prairies, quarante-six de la Colombie-Britannique et des; Territoires et vingt-six de l'étranger. Tables 5a and Sb show the results by gender. There were 259 responses from males and 20 from females. Les tableaux 5a et 5b montrent les résultats par sexe. Deux cent cinquante-neuf hommes et vingt femmes ont répondu au sondage. In each table, the medians and quartiles are given for five-year periods, based on the year of graduation with a Bachelor of Science degree. The final entry in a table covers the entire period for that table. The medians are not reported if there are less than three responses in a period, to maintain confidentiality of the incomes. The quartiles are reported only if there are seven, or more, responses in a period. Chaque tableau contient la médiane et les quartiles pour des pér iodes de cinq ans, basé sur l'année d'obtention du baccalauréat en science. Le dernier item du tableau couvre la période entière du tableau. Les médianes ne sont pas inscrites si moins de trois réponses ont été reçues pour une période, afin de maintenir la confidentialité des revenus. Les quartiles sont représentés seulement si sept réponses, ou plus, ont été reçues pour une période. Finally, Table 6 shows how CAP salaries have evolved during the 1990-97 period. Interpretation of these data is left as an exercise for the reader. Finalement, le tableau 6 montre l'évolution des salaires à l'ACP au cours de la période 1990-1997. Nous laissons au lecteur le plaisir d'interpréter lui-même ces données. 258 P H Y S I C S IN C A N A D A July/August 1998 SONDAGE DE L ' A C P SUR LES REVENUES (1997) The CAP wishes to thank all those who responded to the survey request, and welcomes suggestions for improving future surveys. L'ACP aimerait remercier tous ceux qui ont répondu au sondage et accepte toutes les suggestions qui pourraient améliorer les prochains sondages. TABLE la: SALARY INCOME Year of Graduation Number TABLE 2a: QUALIFICATIONS: BACHELOR'S DEGREE Lower Quartile (k$) Median <k$) Upper Quartile (k$) 43-47 48-52 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 2 2 15 35 52 39 32 46 35 28 11 58.2 81.0 76.1 61.4 60.6 52.0 43.5 30.1 6.0 90.0 93.0 82.2 75.0 69.0 59.5 50.0 43.0 25.7 96.0 103.0 93.8 86.0 78.0 70.0 60.0 54.8 51.4 43-97 297 52.3 69.0 85.0 - Year of Graduation Number Lower Quartile <*$> 63-67 68-72 73-77 78-82 83-87 88-92 93-97 Median (k$) Upper Quartile (k$) 40.0 53.5 12.5 63-97 TABLE 2b: QUALIFICATIONS: MASTER'S DEGREE TABLE lb: PENSION INCOME Year of Graduation Year of Graduation Number 28-32 33-37 38-42 43-47 48-52 53-57 58-62 63-67 68-72 3 3 6 12 13 13 8 1 1 28-72 60 Lower Quartile <k$) Median <k$> 45.8 54.5 49.5 46.2 50.0 47.3 67.5 57.5 60.0 56.0 50.0 Upper Quartile <k$) 65.8 75.6 74.5 54.3 Lower Quartile <k$) Upper Quartile <k$) 1 1 53-57 63-67 68-72 73-77 78-82 83-87 88-92 93-97 7 4 6 3 11 3 60.0 68.0 60.5 50.0 41.0 29.4 53-97 - Median <k$> 56.0 - 48.5 55.0 70.0 TABLE 2c: QUALIFICATIONS: DOCTORATE DEGREE Year of Graduation TABLE lc: CONSULTING INCOME Year of Graduation 38-42 43-47 48-52 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 38-97 Number Lower Quartile (k$) 1 1 6 6 5 1 4 1 6 2 1 1 35 Median Upper Quartile (k$) - 5.0 19.0 5.0 - 20.5 43-47 48-52 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 Lower Quartile (k$ ) 2 2 14 35 49 31 25 39 31 12 3 61.8 81.0 76. 67. 62. 52. 43. 31. Median <k$) 90.0 93.0 84.0 76.0 69.0 59.0 50.0 43.6 54.0 Upper Quartile 96. 103. 94. 86. 78. 70. 60. 56. - 43-97 4.5 73.5 - - 1.5 6.0 TABLE 3a: CURRENT EMPLOYMENT: ACADEMIC 30.0 Year of Graduation Number Lower Quartile <k$) 1 2 10 25 33 15 19 31 16 4 4 88.8 86.5 76.5 68.5 58.0 50.0 45.6 90.2 93.0 85.0 80.0 66.0 56.0 52.0 49.5 27 .6 96.8 101.4 95.8 86.0 78.0 70.0 60.3 160 57.1 76.0 90.0 Median <k$) Upper Quartile (k$) TABLE Id: SCHOLARSHIP INCOME Year of Graduation Number 78--82 88--92 93-• 97 2 9 16 78--97 27 Median <k$) Upper Quartile (k$) 9.7 9.2 16.0 17 .0 18.6 19.4 43-47 48-52 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 9.0 16.5 19.5 43-97 Lower Quartile <k$> LA P H Y S I Q U E AU C A N A D A - juillet à août, 1998 259 1 9 9 7 C A P I N C O M E SURVEY TABLE 3b: CURRENT EMPLOYMENT: GOVERNMENT TABLE 4b: EMPLOYMENT REGION: QUEBEC Year of Graduati jn Number 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 1 8 12 12 4 6 53-97 51 Lower Quartile <k$) 75.8 76.6 57.2 2 1 60.0 Median <k$> Upper Quartile <k$> 83.2 81.0 68.4 70.4 64.5 57.0 — 127.2 83.6 81.0 75.0 82.5 Year of Graduation Number 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 3 5 12 10 9 10 8 10 3 53-97 70 Lower Quartile <k$> 80.2 58.0 60.0 51.5 44.1 27.5 52.8 Median (k$) Upper Quartile(kS) 90. C 85. C 82.0 68.E 70.0 58.0 50.5. 47.Î. 54. CI 88.0 88.2 77.0 64.2 53.9 56.2 63.;: 82.0 TABLE 3c: CURRENT EMPLOYMENT: INDUSTRY Year of Graduation Number 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 1 2 4 9 5 4 9 10 2 53-97 46 Lower Quartile <k$) Median <k$> Upper Quartile (k$) - 63.5 36.0 41.8 84.0 90.0 76.0 59.5 45.0 54.5 51.0 63.4 60.2 85.0 TABLE 3d: CURRENT EMPLOYMENT: GRADUATE Year of Graduation Number 78-82 88-92 93-97 2 3 4 78-97 9 Lower Quartile (k$) Median <k$> Year of Graduation Number Lower Quartile <k$) 43-47 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 1 2 12 17 19 7 19 10 7 3 88.5 77.4 67.0 69.0 55.8 48.8 9.5 Median <k$;> Upper Quartil<9 (k$> 95.5 - 49.0 TABLE 4c: EMPLOYMENT REGION: ONTARIO - 94. S 89.0 73. :i 69.0 65.0 56.0 44.1 29. 1 103.8 93.5 83.0 85.0 74.0 61.5 57.0 Upper Quartile <k$) ? R O V INCES TABLE 4d : EMPLOYMENT REGION: PRAIRIE I 5.5 5.0 4.0 5.5 9.6 Year of Graduation Number Lower Quartile (k$> Medim (k$) Upper Quartile <k$) TABLE 3e: CURRENT EMPLOYMENT: OTHER Year of Graduation Number Lower Quartile <k$) Median <k$) Upper Quartile (k$) 43-47 53-57 63-67 68-72 73-77 78-82 83-87 88-92 1 3 3 3 4 2 4 9 29.8 45.0 34.1 47.5 43-92 29 33.3 49.7 60.0 55.0 90.0 61.4 57.8 TABLE 4a: EMPLOYMENT REGION: ATLANTIC PROVINCES Year of Graduation 53-57 58-62 63-67 68-72 78-82 83-87 93-97 53-97 260 Number 5 3 7 1 3 4 1 24 Lower Quartile (k$ ) 70.0 Median (k$) 89.9 80.0 75.0 PHYSICS IN CANADA 69.5 1 5 3 3 7 5 2 2 53-92 28 Upper Quartile <k$) 79.8 75.8 J u l y / A u g u s t 1998 58.0 52.2 96.0 78.0 86.0 66.3 50.9 73.2 80.0 92.6 TABLE 4e: EMPLOYMENT REGION: BRITISH COLUMBIA AND TERRITORIES Year of Graduation 52.0 44.8 47.8 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 Number 43-47 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 1 3 7 9 4 7 6 5 1 3 43-97 46 Lower Quartile (k$) 80.0 69.8 43.0 Median (k$> 90.5 100.1 82.5 69.7 62.5 64.0 34.5 Upper Quartile (k$) 105.0 95.0 73.0 15.0 53.5 71.0 89.8 SONDAGE DE L ' A C P SUR LES REVENUES ( 1 9 9 7 ) / TABLE 4f: E M P L O Y M E N T REGION: O U T S I D E C A N A D A Year of Graduation Lower Quartile (k$) 48-52 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 2 1 3 4 1 1 2 4 8 48-92 26 Median (k$) TABLE 5b: GENDER: Upper Quartile <*$> Tear of Graduation Number FEMALE Lower Quartile (k$) Median <k$) 39.0 67 .0 40.0 52.0 Upper Quartile (k$) - 134.9 133.5 - 30 6 62.5 39.1 53.4 42 8 66.4 122.0 68-72 73-77 78-82 83-87 88-92 93-97 3 3 7 2 3 2 68-97 20 T A B L E 5a: GENDER: M A L E Year of Graduation Number LIVRES REÇUS Lower Quartile (k$) 27.1 - 29.6 TABLE 6: EVOLUTION OF CAP Median (k$) Upper Quartile (k$) 43-47 48-52 53-57 58-62 63-67 68-72 73-77 78-82 83-87 88-92 93-97 2 2 15 31 48 34 25 38 31 25 8 58.2 80.0 76.6 61.1 60.0 52.8 44.5 33.3 5.5 90.0 91.5 82.2 75.5 70.0 61.0 50.0 43.0 20.4 96.0 103.0 94.9 85.2 81.0 70.0 60.0 55.9 49.2 43-97 259 54.0 70.0 85.3 Year of Graduation Lower Quartile 51.7 41-90 42-91 38-92 39-93 40-94 41-95 47-96 43-97 - B O O K S RECEIVED /LIVRES 411 398 335 318 316 302 254 297 50.0 53.0 55.0 55.0 52.0 52.0 50.0 52.3 60.8 SALARIES Median Upper Quartile <k$) 65.0 70.0 73.0 72.5 72.0 71.0 67.9 69.0 77.2 80.8 85.0 85.0 85.0 85.0 84.0 85.0 <*$) - 61.0 - REÇUS The following books have been received for review. Readers are invited to write reviews, in English or French, of books of interest to them. Books m a y be requested f r o m the book review editor A n d r é Roberge by email at [email protected] or at D e p a r t m e n t of Physics, Laurentian University, S u d b u r y , Ontario, P3E 2C6. Tel: (705) 675-1151, ext. 2234, FAX: (705) 675-4868. Les livres suivants nous sont parvenus pour la critique qui peut être faite en anglais ou en français.Si vous êtes intéressés de nous communiquer une revue critique sur un ouvrage en particulier, vous êtes invités à vous mettre en rapport avec le responsable de la critique des livres, André Roberge par courrier électronique via [email protected] ou au: Département de physique, Université Laurentienne, Sudbury, Ontario, P3C 2C6. Tél. (705) 675-1151, poste 2234. Télécopieur: (705) 675-4868 Recently, questions have been raised regarding the availability of books for review a n d that of the editor. The following guidelines s h o u l d help to clarify the normal process: within a w e e k of receiving a book request (email preferred), an a c k n o w l e d g e m e n t is sent; another message confirming the availability or non-availability of the requested book(s) s h o u l d be sent within t w o weeks; the two weeks delay is u s e d to c o m p e n s a t e for u n e v e n n e s s in mail delivery time of PiC a n d give all C A P m e m b e r s equal access to books for review. In exchange for receiving a free book, the reviewer is expected to write a review within approximately 3 m o n t h s of receiving the book. Dernièrement, certaines questions ont été soulevées quant à la disponibilité des livres pour revue et celle de l'éditeur de cette chronique. Normalement, les critiques potentiels devraient recevoir un accusé de réception (courrier électronique préféré) en-dedans d'une semaine, et un autre message indiquant la disponibilité du ou des livres en question en-dedans de deux semaines; le délai de deux semaines est utilisé pour compenser les délais de distribution par courrier de la Physique au Canada, et donner à tous les membres de l'ACP un accès égal aux livres pour revue. En échange de recevoir un livre gratuitement, les critiques devraient soumettre leur revue dans les trois mois suivant la réception du livre. LA P H Y S I Q U E AU C A N A D A juillet à août, 1998 261 BOOKS RECEIVED / B O O K REVIEWS GENERAL INTEREST Mind Matters; exploring the world of artificial intelligence, J.P. H o g a n , Del Rey (Ballantine Books), 1997, pp: xvi+381, ISBN 0-345-41240-0; Q335.H634; Price: 35 (he) G R A D U A T E TEXTS A N D PROCEEDINGS Acoustical Imaging, V o l u m e 23, edited by S. Lees and L.A. Ferrari, Plenum , 1997, pp: xvi+653, ISBN 0-306-45768-7; QC244.5.I.5; Price: $165 (he) P. van Baal, NATO ASI Series B368, Plenum , 1998, pp: x+550, ISBN 0-306-45826-8; Price: $155 (he) Current Problems in Condensed Matter, New edited by J.L. Moran-Lopez, Plenum , 1998, pp: xi+358, ISBN 0-306-45915-9; Price: $125 (he) Theory, Edited by P. H. Damgaard and ]. Jurkiewicz, NATO ASI Series B366, Plenum , 1998, pp: ix+364, ISBN 0-306-45816-0; QC174.45.A1N45; Price: $125 (he) Diagnostics for experimental Thermonuclear Fusion Reactors 2, edited by P. E. Stott et. al., Plenum, 1998, pp: xiii+609, ISBN 0-306-45835-7; Price: $149.50 (he) Advances in Nuclear Physics, v o l u m e 24, Electronic Density Functional Theory; Recent Progress and N e w Directions, Edited edited by J.W. Negele and E. Vogt, Plenum, 1998, pp: xv+210, ISBN 0-306-45757-1; QC173.A2545; Price: $89.50 (he) by J.F. Dobson, G. Vignale and M.P. Das, Plenum , 1998, pp: ix+395, ISBN 0-306-45834-9; Price: $125 (he) Atoms and Molecules in Strong External Functional and Smart Materials; Structural Evolution and Structure Analysis, Z.L. Fields, edited by P. Schmelcher and W. Schweizer, Plenum , 1998, pp: ix+336, ISBN 0-306-45811-X; QC176.8.E4A86; Price: $110 (he) Wang and Z.C. Kang, Plenum , 1998, pp: x x i i i + 5 1 4 , ISBN 0-306-45651-6; TA418.9.S62W36; Price: $125 (he) Black Holes and Relativistic Stars, Edited Galaxy Morphology by R.M. Wald, Univeristy of Chicago Press, 1998, pp: xii+278, ISBN 0-226-87034-0; QB843.B55B585; Price: $50 (he) Sidney van den Bergh, Cambridge University Press, 1998, pp: xi+111, ISBN 0-521-62335-9; QB857.V36; Price: $39.95 (he) Confinement, Duality, and Nonperturbative Aspects of QCD, edited by Geometrical Vectors, G. Weinreich, The and Correlations in Quantum in Field Many-Fermion Systems, edited by V. Z. Kresin, Plenum , 1998, pp: viii+296, ISBN 0-306-45823-3; Price: $110 Pioneering Ideas for the Physical Chemical Sciences, e d i t e d by and W. Fleischhacker and T. Schonfeld, Plenum, pp: ix+320, ISBN 0-306-45684-2; QD22.L85P56; Price: $110 (he) Semiclassical Physics, M. Brack a n d R.K. Bhaduri, Addison Wesley (Frontiers in Physics, Vol. 96), 1997, pp: xviii+444, ISBN 0-201-48351-3; Price: ?? (he) [2 copies available for review] Surface Diffusion; Atomistic and Collective Processes, edited by M.C. Tringides, NATO ASI Series B360, Plenum , 1997, pp: xi+724, ISBN 0-306-45613-3; QC185.S87; Price: $175 (he) University of Chicago Press, 1998, pp: x+115, FRACTALS A N D CHAOS: A N ILLUSTRATED COURSE, by P.S. Addison, IOP Publishing, 1997, ppxii+256, ISBN 0-7503-0400-6 (pbk,-0399-9 he), QA614.86.A23, Price:$39 (pbk; 120 he). Both of the subjects of this book are currently 'Hot' topics in modern physics although they have been known and studied for many years. The idea of fractional dimension was made prominent by Mandelbrot in his 1977 book. Addison starts by considering measures of length and shows how the scale of the measuring rod used can lead to different results. From this he leads into the idea of Hausdorf measure and to a consequent definition of fractal dimension. The presentation is very readable and the examples provided with each chapter will motivate students to continue reading. The second part of the book is devoted to chaotic behaviour. This can arise during the solution of a variety of problems which range from Newton-Raphson iteration to the solution of coupled differential equations. Typical of the material PHYSICS IN CANADA Pair Developments Classification, B O O K R E V I E W S / CRITIQUES 262 ISBN 0-226-89048-1 (pbk: -89047-3 he); QC20.7.V4W45; Price: $16 (pbk; $32 he) [Note: this book is currently being reviewed.] July/August 1998 DES LIVRES presented is the chaotic behaviour of a journal bearing and Rayleigh-Benard convection. The book ends with solutions to the examples, a very comprehensive bibliography and a good index. It would make an excellent course text. Andrew D. Booth, Sooke, B.C. B I L L I O N S A N D B I L L I O N S : T H O U G H T S O N LIFE A N D D E A T H A T T H E B R I N K O F T H E M I L L E N N I U M , Carl Sagan, Random House, 1997, pp: xii+241. ISBN 0-679-41160-7; Q173.S24; $33.50 (he) Summary: The book is a mixture of popular science, pseudo-science, social commentary, and political commentary. There are exaggerations, mistakes, lack of sufficient context, misleading parts, and emotionalism. The last chapter anc an epilogue describe Sagan's final illness and death. I do not recommend this book. LIVRES REÇUS The first t w o chapters s e e m e d to m e the most informative, though a r o u n d the high school level. They discussed large numbers, scientific notation, metric prefixes, exponential growth, and radioactive decay. T O P O G R A P H I C EFFECTS I N S T R A T I F I E D FLOWS, by However, there are problems in these chapters. Page 4 said there are 31.7 million seconds in a year. I calculated 31 622 400 seconds in a leap year. Page 6 said c o n f u s i o n still exists in use of the w o r d s 'millions', 'billions', and 'trillions'. The next p a r a g r a p h said Europe u s e d 'milliard' for a billion (that is, a thousand million) but took G e r m a n '50 millarden' as 50 trillion. The s t u d y of w e a t h e r patterns, particularly over mountains, usually involves the flow of w a r m and cool layers over each other. Likewise c o a s t / o c e a n / atmosphere flow presents similar problems. On a smaller scale the effect of tidal motion in fiords (such as Knight Inlet, B.C.) obstructed by sills is an active topic of research in Ocean Physics. Peter Baines is a leading authority in this field and this book represents the result of several decades of active research. Chapter 2 included a discussion of AIDS (acquired i m m u n e deficiency syndrome), described as an epidemic disease. I have a different view, partly f r o m h a v i n g w o r k e d in a provincial laboratory which tested for AIDS. I w a s told several times that AIDS is not a disease, but a s y n d r o m e . It is also not an epidemic: not e n o u g h people are affected. I question the statistics given for p o p u l a t i o n g r o w t h because I remember invention a n d guessing in similar work. Chapter 3 began declaring "we can't help" watching football-like sports on television (I never watch them), a n d went on to suggest that present-day love of sports is descended f r o m hunter-gatherer cultures. P.G. Baines, Cambridge University Press, 1995, pp:xvi+482, ISBN 0-521-62923-3 (pbk; -43501-3 he), Price $ 34.95 (pbk; $80 he) The first part of the book provides a firm theoretical foundation for the theory of stratified flow over obstacles and is well illustrated by observational material. The second part describes experimental tank techniques, many developed by the a u t h o r and leads to the final chapters in which atmospheric and oceanographic experimental results are presented and analysed. There index. would course is a comprehensive bibliography and a good Although there are n o student problems the book make an excellent senior u n d e r g r a d u a t e or graduate text. A n d r e w D. Booth, Sooke, B.C. Chapter 4 said ocean w a v e s are two-dimensional, w h i c h is an abstraction since e v e n the n a k e d eye can observe vertical motion along with the horizontal motion of ripples. ® C.A.P. 1998. All rights reserved. While Chapter 2 p r e s e n t e d h u m a n population g r o w t h as a danger, C h a p t e r 8 w a r n e d of lower s p e r m counts. If one bothers me, w h y s h o u l d the other? Chapter 10 discussed the alleged destruction of the atmospheric ozone layer by chlorofluorocarbons (CFCs) a n d described attempts to eliminate t h e m to protect the ozone. The chapter did not m e n t i o n another possible reason for eliminating CFCs: Patents on t h e m are d y i n g out or have d o n e so; thus profiting f r o m their m a n u f a c t u r e is harder. The book also discussed global w a r m i n g , the relations between science a n d religion, abortion, censoring of an article in a Russian magazine, the golden rule, nuclear w e a p o n s , military budgets, a n d Carl Sagan's final sickness. I w a s reminded of frequent radio or television discussions. There are references at the back of the book. This book m a y be useful for a course in critical thinking: Students could be challenged to check the validity of the book's contents. I d o not r e c o m m e n d it otherwise. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by the C.A.P. The above permission does not extend to other kinds of copying, such as copying for general distribution, for advertising, or promotional purposes, for creating new collective works, or for resale. For such copying, arrangements must be made with the publisher. O F F P R I N T PRICE L I S T (B&W/no covers) 8 1 / 2 x 1 1 Corner Stapled - (GST/HST extra) Add'l Copies 50 100 200 300 2 pages 4 pages 6 pages 2 pages $ $ $ $ $ 50.00 $ 65.00 $ 95.00 $135.00 $ 60.00 $ 90.00 $120.00 $175.00 $15.00 $ 22.50 $35.00 $47.50 40.00 50.00 70.00 95.00 Reprints of previously published articles can be purchased by special order. Authors should contact the CAP Office for a price quote. David P. M a r o u n [email protected] LA P H Y S I Q U E AU CANADA juillet à août, 1998 263 EMPLOYMENT ADS York University The Department of Physics at McGill University Experimental High Energy Physics Postdoctoral Research Position The experimental high energy physics group at York University in Toronto has an immediate opening for a research associate to participate in the construction and commissioning of a straw-tube tracker which is to be installed in ZEUS in order to exploit the major luminosity upgrade of HERA in the year 2000. Applicants must have a recent Ph.D. in elementary particle physics, and demonstrated hardware and software experience. The first year of the appointment will be spent in Toronto constructing the detector and then the successful candidate is expected to become resident in Hamburg to partake in detector installation and commissioning. The York group is also involved in ZEUS physics analysis, with particular emphasis on heavy quark physics, and the successful candidate will be encouraged to participate in physics analysis. Interested candidates should send a cover letter, a curriculum vitae, and arrange to have three letters of recommendation sent to: Prof. Scott Menary Department of Physics & Astronomy 234 Petrie Science Building York University 4700 Keele Street Toronto, Ontario, Canada, M3J 1P3 E-mail inquiries should be directed to [email protected] . Screening of candidates will begin immediately. In accordance with Canadian immigration regulations, this advertisement is directed in the first instance to Canadian citizens or permanent residents. Nonetheless, anyone interested is encouraged to apply. York University strongly encourages applications by women and members of minority and aboriginal groups. M Technologies Inc. MPB Technologies Inc. is seeking candidates to nominate for Natural Science and Engineering Research Council of Canada Industrial Research Fellowships. The Fellowships will normally be tenable in the Laboratories of MPB Technologies Inc. located at Pointe Claire, Quebec or Edmonton, Alberta. Projects in which successful candidates may be involved include: Laser and Laser Applications Optical Fibre and Electrooptic Devices Optical and Spectroscopic Techniques High Speed Digital Telecommunications Electromagnetic Measurements Salaries and other benefits are the same as for permanent staff of equivalent experience. Interested recent graduates, individuals currently completing postdoctorate fellowships, or candidates who will graduate in the near future with a background in physics, electrical engineering or computer science and who are Canadian citizens or landed immigrants are invited to write or call: Human Resources Department MPB Technologies Inc. 151 Hymus Boulevard Pointe Claire, Quebec CANADA H 9 R 1 E 9 P H Y S I C S IN CANADA The department is also active in High Energy Physics, Nuclear Physics and Theoretical Atmospheric Physics. For more information about McGill and the Physics Department you are invited to consult our home page at http://www.physics.mcgill.ca. We seek candidates with proven or potential excellence in both research and teaching. Applications together with a detailed curriculum vitae, a statement of research and teaching interests and three letters of reference should be sent to: Prof. J. Barrette, Chair Department of Physics, McGill University 3600 University Street, Montreal, Quebec, Canada, H3A 2T8 Review of applications will begin October 20,1998. In accordance with Canadian Immigration requirements, this advertisement is directed to Canadian citizens and permanent residents of Canada. McGill University is committed :o equity in employment. The Department of Physics will make a tenure track appointment at the rank of Assistant Professor with an expected starting date of July 1,1999 This is one of two appointments being made in the area of experimental condensed matter physics. An appointment at a higher rank nay also be considered. We seek candidates with a Ph.D. in Physics, with proven or potential excellence in both research and teaching. Our goal is to find a candidate with a strong experimental background and an innovative, interdisciplinary outlook. We are interested in the general area of physics lar from equilibrium: nonlinear physics (e.g. pattern formation, granular media, fracture) or biological physics (e.g. DNA dynamics, cheir.otaxis) We also invite outstanding candidates working in related areas of experimental soft condensed matter physics to apply. Salary will be commensurate with qualifications and experience. Applications, including a curriculum vitae, a summary of proposed research and three letters of reference should be sent to: Professor Pekka Sinervo, Chair University of Toronto, Department of Physics 60 George St., Toronto, Ontario, Canada M5S1A7 The deadline for the receipt of applications and letter of recommendation i:; October 31st, 1998. We urge prospective candidates to visit our homepage at http:/ / www.physics. utoronto.ca/. In accordance with Canadian immigration requirements, this advertisement is directed to both Canadian citizens and permanent residents of Canada. The University of Toronto is committed to e m p l o y m e n t equity and encourages applications from all qualified individuals including w o m e n , members of visible minorities, aboriginal persons, and persons w i t h disabilities. Telephone: (514) 694-8751 Fax: (514)695-7492 264 The applicant will be expected to become a member of the Centre for the Physics of Materials which includes faculty members from the Physics and Chemistry Departments as well as research scientists in industrial laboratories. The focus of the Centre is on research at the boundary between Condensed Matter Physics and Materials Science. It has a wide range of preparation, measurement and characterization facilities and one of its major strengths is the extensive interaction and collaboration that exists between theory and experiment. University of Toronto II Department of Physics Tenure Track Faculty Position Experimental Nonlinear or Biological Physics INDUSTRIAL RESEARCH FELLOWSHIPS • • • • • invites applications for a tenure-track position at the rank of Assistant Professor, beginning no later than September 1999. The appointment will be in the area of experimental Condensed Matter Physics with an emphasis for candidates in the area of mesoscopic or nanoscale science. July/August 1998 C O M I N G IN SEPTEMBER / À VENIR EN SEPTEMBRE SPACE, W E A T H E R A N D THE L'ESPACE> LE TEMPS ET L ENVIRONMENT/ 'ENVIRONNEMENT Guest E d i t o r / R é d a c t e u r en chef invité: Prof. A . H a m z a , U N B FEATURING / ARTICLES DE FOND: "Space W e a t h e r : M a g n e t o s p h e r i c M o r p h o l o g y a n d M a p p i n g b e t w e e n the Ionosphere a n d Magnetosphere" by/par Eric F. Donovan and Brian J. Jackel "Space Physics: From M a c r o , T h r o u g h M e s o , to Microscales" by/par A.M. Hamza and E.F. Donovan Physics in Canada La Physique au Canada "The Space E n v i r o n m e n t a n d the C a n a d i a n Space A g e n c y " ! by/par Terry Hughes and Dave Kendall " G e o m a g n e t i c Effects o n Electrical Systems" by/par D. H. Boteler " G e o m a g n e t i c Forecasting in Canada: A R e v i e w " by/par R.L. Coles and H-L. Lam kj "The International S u p e r D A R N Space W e a t h e r HF-Radar N e t w o r k " by/par George Sofko "Probing the Near-Earth Space E n v i r o n m e n t w i t h Small Payloads" by/par D. J. Knudsen " N o w c a s t i n g of Space W e a t h e r U s i n g the C A N O P U S M a g n e t o m e t e r Array" by/par Gordon Rostoker "Forecasting Space W e a t h e r " by/par Robert Rankin and William Liu Visit the Physics in Canada website (http://www.cap.ca/pic) for detailed abstracts on each of these articles. Visitez le site Web de La Physique au Canada (http://www.cap.ca/pic) pour voir les résumés détaillés de chacun de ses articles. 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