LA PHYSIQUE AU CANADA

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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
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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!
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Hffjl »
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Glassman.
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concept
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O u t p u t p o w e r is 4 t o 1 5 k W . W i t h
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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
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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
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PERSONNEL D U BUREAU DE L'ACP
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number of staffing changes. We took this opportunity
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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: [email protected] 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: [email protected] 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: [email protected] 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: [email protected] 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 [email protected] sims. nrc. ca
Medical and Biological/médicale et biologique:
Dr. David Chettle, McMaster University
Tel: (905) 525-9140 x27340; Fax: (905)
E-mail: [email protected] 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: [email protected] triumf. ca
Full Members/Membres titulaires:
Dr. Robert C. Barber, Univ. of Manitoba
Tel: (204) 474-9817 ; Fax: (204)
269-8489
E-mail: [email protected] umanitoba. ca
Optics & Photonics/Optique et photonique:
Dr. Michel Tetu, Laval University
Tel: (418) 656-2146 ; Fax: (418)
E-mail: michel. [email protected] 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: [email protected] 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: [email protected] 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. [email protected] 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: [email protected] cc. uregina. ca
Ontario - Central & North:
Prof. Aephraim Steinberg, University of Toronto
Tel: (416) 978-0713; Fax: (416)
978-2537
E-mail: [email protected] 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: [email protected] 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: [email protected] 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: [email protected] 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: [email protected] 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: [email protected]
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
[email protected] its.mcw.edu
6-9 1999 CAP Conference, Univ. of
New Brunswick, Fredericton, NB; email: [email protected] 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
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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).
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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
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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
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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
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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
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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
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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
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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
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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).
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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
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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
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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.
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PHYSICS IN CANADA
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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.
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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.
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Copyright of original articles published in Physics
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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.
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ACKNOWLEDGEMENT
The authors gratefully acknowledge financial
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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
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0.01
Fig. 4
( C O H E R E N T GENERATION...)
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reproduction en vue d ' u n e distribution générale, à
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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
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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
•
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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
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GAMBLE TECHNOLOGIES
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EG&G ORTEC
Leaders in nuclear instruments, detectors, systems;
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ORDELA, Inc.
PEFRALS alpha measurement system - lowest
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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
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Industrial radiation measurement systems
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Compact, low cost Windows based TLD systems
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Radiation measurement system for health physics and
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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
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Andor Technology Limited
Advanced Scientific CCD Cameras for Imaging &
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available in a scientific camera. TE cooling to -90(C
available without periodic vacuum pumpout or nitrogen
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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
•
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Andor Technology Limited
Low cost Benchtop RAMAN spectrometer
EG&G Princeton Applied Research
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New modular low cost FTIR system
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Optical Surface Profiler, SRET, Scanning Kelvin Probe;
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GTL maintains a distribution and service facility in
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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,
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customers in the world market and for stronger ties with local
research and industrial organizations.
O C I VACUUM MICROENGINEERING
Primary Area of Expertise
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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
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INO's rate of self-financing jumped 10% over last year and
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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
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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.
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David P. M a r o u n
[email protected]
LA P H Y S I Q U E AU CANADA
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263
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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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1998 SEPTEMBER/OCTOBER ISSUE OF PHYSICS IN C A N A D A
"Space, Weather, and the Environment"
N U M É R O DE SEPTEMBRE/OCTOBRE 1998 DE LA PHYSIQUE A U C A N A D A
"L'espace, le temps et l'environnement"
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