Standard Guide to Procedures for Calibrating Automatic Pedestrian SNM Monitors

SCOPE
1.1 This guide covers calibrating the energy response of the radiation detectors and setting the discriminator and alarm thresholds used in automatic pedestrian special nuclear material (SNM) monitors.
1.2 Automatic pedestrian SNM Monitors and their application are described in Guide C 1112, which suggests that the monitors be calibrated and tested when installed and that, thereafter, the calibration should be checked and the monitor tested with SNM at three-month intervals.
1.3 Dependable operation of SNM monitors rests, in part, on an effective program to test, calibrate, and maintain them. The procedures and methods described in this guide may help both to achieve dependable operation and obtain timely warning of misoperation.
1.4 This guide can be used in conjunction with other ASTM standards. illustrates the relationship between calibration and other procedures described in standard guides, and it also shows how the guides relate to an SNM monitor user. The guides below the user in the figure deal with routine procedures for operational monitors. Note that Guide C 993 is an in-plant performance evaluation that is used to verify acceptable detection of SNM after a monitor is calibrated. The guides shown above the user in give information on applying SNM monitors (C 1112) and on evaluating SNM monitors (C 1169) to provide comparative information on monitor performance.

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Historical
Publication Date
09-Jan-2002
Technical Committee
Current Stage
Ref Project

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ASTM C1189-95(2001) - Standard Guide to Procedures for Calibrating Automatic Pedestrian SNM Monitors
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: C 1189 – 95 (Reapproved 2001)
Standard Guide to
Procedures for Calibrating Automatic Pedestrian SNM
1
Monitors
This standard is issued under the fixed designation C 1189; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This guide covers calibrating the energy response of the
radiation detectors and setting the discriminator and alarm
thresholds used in automatic pedestrian special nuclear mate-
rial (SNM) monitors.
1.2 Automatic pedestrian SNM Monitors and their applica-
tion are described in Guide C 1112, which suggests that the
monitors be calibrated and tested when installed and that,
thereafter, the calibration should be checked and the monitor
tested with SNM at three-month intervals.
1.3 Dependable operation of SNM monitors rests, in part,
on an effective program to test, calibrate, and maintain them.
The procedures and methods described in this guide may help
both to achieve dependable operation and obtain timely warn-
ing of misoperation.
1.4 This guide can be used in conjunction with other ASTM
standards. Fig. 1 illustrates the relationship between calibration
FIG. 1 The Relationship of Calibration to Other Procedures
and other procedures described in standard guides, and it also
Described in Standard Guides for SNM Monitors
shows how the guides relate to an SNM monitor user. The
guides below the user in the figure deal with routine procedures
for operational monitors. Note that Guide C 993 is an in-plant
E 876 Practice for Use of Statistics in the Evaluation of
3
performance evaluation that is used to verify acceptable
Spectrometric Data
detection of SNM after a monitor is calibrated. The guides
3. Terminology
shown above the user in Fig. 1 give information on applying
SNM monitors (C 1112) and on evaluating SNM monitors
3.1 Definitions of Terms Specific to This Standard:
(C 1169) to provide comparative information on monitor
3.1.1 calibration—a multistep procedure that uniformly
performance.
adjusts the energy response of a monitor’s detector array and
sets the operating parameters of its detection circuits for
2. Referenced Documents
optimum performance. In a few monitors, an additional analog
2.1 ASTM Standards:
adjustment of a signal detection circuit is required.
2
C 859 Terminology Relating to Nuclear Materials
3.1.2 SNM—special nuclear material: plutonium of any
233
C 993 Guide for In-Plant Performance Evaluation of Auto-
isotopic composition, U, or enriched uranium as defined in
2
matic Pedestrian SNM Monitors
Terminology C 859.
C 1112 Guide for Application of Radiation Monitors to the
3.1.2.1 Discussion—This term is used here to describe both
2
Control and Physical Security of Special Nuclear Material
SNM and strategic SNM, which is plutonium, uranium-233,
235
C 1169 Guide for Laboratory Evaluation of Automatic Pe-
and uranium enriched to 20% or more in the U isotope.
2
destrian SNM Monitor Performance
3.1.3 SNM Monitor—a radiation detection system that mea-
sures ambient radiation intensity, determines an alarm thresh-
1
old from the result, and then when it monitors, sounds an alarm
This guide is under the jurisdiction of ASTM Committee C–26 on Nuclear Fuel
Cycle and is the direct responsibility of Subcommittee C26.12 on Safeguard if its measured radiation intensity exceeds the threshold.
Applications.
Current edition approved Sept. 10, 1995. Published November 1995. Originally
published as C 1189 – 91. Last previous edition C 1189 – 91.
2 3
Annual Book of ASTM Standards, Vol 12.01. Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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C 1189
3.1.3.1 Discussion—The automatic pedestrian SNM moni- 7.2.1 Inorganic Scintillation Detectors, such as sodium
tor discussed here is a walk-through or wait-in portal or iodide [NaI(T1)], detect gamma rays but have little response to
monitoring booth. neutrons from SNM. This detector is useful for detecting
unshielded SNM.
4. Summary of Guide
7.2.2 Neutron Proportional Counters, containing BF
3
3
4.1 This guide covers various instructions for calibrating
or He as a converter gas, detect thermal neutrons and are used
SNM pedestrian monitors for optimum performance in normal
with a moderator to thermalize fast neutrons from SNM. This
operation. The order of procedures is as follows.
detector is useful for detecting unshielded or shielded pluto-
4.1.1 The energy response of inorganic or organic scintilla-
nium.
tion detectors or of neutron proportional coun
...

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