NBR Natural Background Reduction

Eberline
NBR-SERIES
Natural Background Reduction
FEATURES
n
Separates artificial from naturally
occurring isotopes in fluctuating back
grounds
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Identifies artificial sources easily even in
low count rate, low background conditions
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Three versions allow a choice between
detector size, power requirements, and
the application criteria to determine
the optimum detection system
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Connects to Global Positioning System
(used mapping software) for positive
location identification
INTRODUCTION
The NBR-Series of instruments employs a patented Natural Background Reduction (NBR)
technology which separates natural radioactivity from any artificial (man-made or
enhanced) materials. Unlike more complicated spectroscopy-based systems, the NBR
designs employ standard plastic scintillation detectors and simple electronics which
enhance the user-friendliness when deployed into the field. A key advantage of this technology is its ability to detect very small amounts of contamination while in the presence of
fluctuating backgrounds.
Natural background fluctuations are the result of many different variables such as elevation, self-shielding (ie water), building materials, soil types, time of day, solar activity, and
weather patterns that create varying radon levels due to
changing ambient atmospheric pressure. The NBR technique removes the background component allowing the
accurate measurement of sources.
Figure 1 reveals the effectiveness of NBR in detecting a
small 137Cs source in the presence of a changing ambient gamma background. The NBR technique makes
evaluating the measured gamma measurement data
much simpler. Please note that this technique works with
either:
Figure 1
Eberline Instruments
http://www.eberline.com
a) Moving sources and fixed equipment or
b) Moving equipment and fixed sources
P.O. Box 2108, Santa Fe, NM 87504-2108
Phone: 505-471-3232
Fax: 505-473-9221
Eberline
NBR-Series
Advanced Digital Filter
The NBR technique is both reliable and
fast. In part, this is due to the Advanced
Digital Filter (ADF). Figure 2 shows the
effectiveness of the ADF method in determining the count rates present while eliminating unnecessary statistical fluctuations.
This greatly contributes to the technique by
making the data analysis much simpler in
both the NBR and gross count rate channels.
Figure 2
APPLICATIONS
Applications for NBR include remedial actions where manmade isotopes are to be measured in the presence of natural radiation; checking cargoes on trucks, railcars and ships;
border control points; or measuring any other objects or persons necessary to prevent the
smuggling or accidental transport of manmade sources.
AVAILABLE MODELS
NBR-Surveyor
A handheld survey instrument based on the popular FH40G survey meter employing an
organic scintillator and additional electronics
which provide the NBR capability.
The instrument has a measurement range
between 0.1 µR/h to 10 mR/h using the
organic scintillator and can also be used in
the dose rate range between 1-µR/h to 2.5
R/h at energies from 48 keV to 1.3 MeV
using the proportional tube in the FH40G.
At ambient background levels, this instrument
can detect as little a 3 µR/h of 137Cs as artificial even in widely fluctuating backgrounds.
This portable unit is capable of data logging
up to 256 points which can be retrieved by a PC for further analysis and reporting.
Eberline Instruments
http://www.eberline.com
P.O. Box 2108, Santa Fe, NM 87504-2108
Phone: 505-471-3232
Fax: 505-473-9221
Eberline
NBR - Mobile
A rugged, shock resistant system mounted in an aluminum
equipment case comprising a 5
Liter organic scintillator with a
sensitivity of 200 cps per µR/h.
The integrated Global
Positioning System (GPS)
allows each logged measurement to be associated with a
coordinate which can be applied
to either a commercial mapping
program or any digitized map.
An optional FH-40G instrument
provides local display and
alarming as well as dose rate
measurement between 10 uR/h
to 2.5 R/h.
NBR-Passage
A passageway adaptation of the NBR concept
permits monitoring of personnel, baggage handling systems, or any other process where objects
pass through a given area.
Fully self-contained, this unit only requires a 120
Vac power source connection to become operable.
Alarms may be set to either be non-latching or to
require a manual reset. Alarm relays permit
remote monitoring.
NBR-Series
Natural Background Reduction
SPECIFICATIONS
Note: The isotope Radium-226 is detected as "naturally occurring".
Isotopes of Uranium (depleted and enriched) are detected as "artificial."