ANSI N42.38-2006, American National Standard Performance

American National Standard

Performance Criteria for Spectroscopy-

Based Portal Monitors Used for Homeland Security

Accredited by the American National Standards Institute

Sponsored by the

National Committee on Radiation Instrumentation, N42

I E E E

3 Park Avenue

New York, NY 10016-5997, USA

22 January 2007

ANSI N42.38-2006

ANSI N42.38-2006




Sponsor

National Committee on Radiation Instrumentation, N42

Accredited by the

American National Standards Institute

Secretariat

Institute of Electrical and Electronics Engineers, Inc.

Approved 28 August 2006

American National Standards Institute

Abstract: The performance requirements for radionuclide identifying portal monitors, also referred to as spectroscopic portal monitors, are described in this standard. The requirements stated are based on monitors used in support of efforts associated with the U.S. Department of

Homeland Security.

Keywords: gamma spectroscopy, homeland security, instrument test, portal monitors, radiation detectors, radionuclide identification

_____________________

The Institute of Electrical and Electronics Engineers, Inc.

3 Park Avenue, New York, NY 10016-5997, USA

Copyright © 2007 by the Institute of Electrical and Electronics Engineers, Inc.

All rights reserved. Published 22 January 2007. Printed in the United States of America.

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Engineers, Incorporated.

Print: ISBN 0-7381-5284-6

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SH95598

SS95598

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Introduction

This introduction is not part of ANSI N42.38-2006, American National Standard Performance Criteria for Spectroscopy-Based Portal Monitors Used for Homeland Security.

This standard is the responsibility of the Accredited American Standards Committee on Radiation

Instrumentation, N42. The standard was approved by the N42 letter ballot of July–August 2006.

Notice to users

Errata

Errata, if any, for this and all other standards can be accessed at the following URL: http:// standards.ieee.org/reading/ieee/updates/errata/index.html. Users are encouraged to check this URL for errata periodically.

Interpretations

Current interpretations can be accessed at the following URL: http://standards.ieee.org/reading/ieee/interp/ index.html.

Patents

Attention is called to the possibility that implementation of this standard may require use of subject matter covered by patent rights. By publication of this standard, no position is taken with respect to the existence or validity of any patent rights in connection therewith. The IEEE shall not be responsible for identifying patents or patent applications for which a license may be required to implement an IEEE standard or for conducting inquiries into the legal validity or scope of those patents that are brought to its attention. v

Copyright © 2007 IEEE. All rights reserved.

Participants

At the time it approved this standard, the Accredited Standards Committee on Radiation Instrumentation,

N42, had the following membership:

Michael P. Unterweger , Chair

Morgan Cox , Deputy Chair

William Ash , Administrative Secretary

Organization Represented...................................................................................................Name of Representative

Bartlett Services ………………………………………………………...………….…………………Morgan Cox

Canberra ……………………………………………………………………………………………Markku Koskelo

Chew, M.H …………………………………………………………………...….…………………….Jack M. Selby

Commerce Dept, U.S. NIST ………………………………………………………..…………...Michael Unterweger

..............................................................................................................................................................Louis Costrell ( Alt.

)

Consultant ..................................................................................................................................................Frank X. Masse

Department of Homeland Security …………………………..………………………………………….Peter Shebell

Entergy-ANO ……………………………………………..…………………………………………...Ron Schwartz

Health Physics Society ………………………………………………….……………………………….Sandy Perle

IEEE ..............................................................................................................................................................Louis Costrell

...............................................................................................................................................................Julian Forster ( Alt.

)

.........................................................................................................................................................Anthony Spurgin ( Alt.

)

...................................................................................................................................................Michael Unterweger ( Alt.

)

International Medcom …………………………………..…………………………………………………Don Sythe

Lawrence Berkeley National Lab ……………………….…………………………………………Edward J. Lampo

Lawrence Livermore National Lab ………………………..…………………………………………...Gary Johnson

NASA, GSFC ……………………………………………..………………………………….Sachidananda R. Babu

Nuclear Regulatory Commission ………………………………………………………..……………..Cynthia Jones

Nuclear Stds Unlimited ……………………………………………………..………………………Al N. Tschaeche

ORNL ……………………………………………………………………………..………………Peter J. Chiaro, Jr.

………………………………………………………………..………………………………...Charles Britton ( Alt.

)

ORTEC ………………………………………………………………..…………………………..Ronald M. Keyser

Pacific NW Labs ………………………………………………………..…………………………...Richard Kouzes

Swinth Associates …………………………………………………..…………………………….Kenneth L. Swinth

U.S. Army …………………………………………………………..………………………………Edward Groeber

Members-At-Large ……………………………………………………………….…………………....Ernesto Corte

……………………………………………………………………………………………….....Joseph C. McDonald

…………………………………………………………………………………………………….…..Paul L. Phelps

…………………………………………………………………………………………………….….Joseph Stencel

……………………………………………………………………………………………………….. Lee J. Wagner vi


At the time this standard was approved, Subcommittee N42.HSI had the following membership:

Michael P. Unterweger , Co-Chair

Morgan Cox , Co-Chair

Paul Bailey

Peter J. Chiaro, Jr.

David Gilliam

Mark Hoover

Cynthia G. Jones

Ronald Keyser

Richard Kouzes

Joseph C. McDonald

Leticia Pibida

Brain Rees

Peter Shebell

David Trombino

At the time this standard was approved, the ANSI 42.38 Working Group had the following members:

Peter J. Chiaro, Jr.

, Chair and Project Leader

Carl Czajkowski

Chuck Finfrock

Jens Hovgaard

Adam Hutter

Cynthia Jones

Ron Keyser

Dick Kouzes

George Lasche

Dean Mitchell

Richard Oxford

Leticia Pibida

Alan Proctor

Brian Rees

Dave Trombino

Michael P. Unterweger vii


Contents

1. Overview .................................................................................................................................................... 1

1.1 Scope ................................................................................................................................................... 1

1.2 Purpose ................................................................................................................................................ 1

1.3 General ................................................................................................................................................ 2

2. Normative references.................................................................................................................................. 2

3. Definitions.................................................................................................................................................. 4

3.1 General definitions .............................................................................................................................. 4

3.2 Definitions of particular relevance to ANSI N42.38 ........................................................................... 8

4. General considerations ............................................................................................................................... 9

4.1 Standard test conditions....................................................................................................................... 9

4.2 Units and uncertainties ........................................................................................................................ 9

4.3 Special word usage ............................................................................................................................ 10

5. Design requirements................................................................................................................................. 10

5.1 General characteristics....................................................................................................................... 10

5.2 Physical configuration ....................................................................................................................... 12

5.3 Spectral identification........................................................................................................................ 13

5.4 Indication features ............................................................................................................................. 14

5.5 Occupancy and speed sensors for vehicle monitors........................................................................... 14

5.6 Markings............................................................................................................................................ 14

5.7 Power supply ..................................................................................................................................... 14

5.8 Battery life-time................................................................................................................................. 15

5.9 Protection of switches........................................................................................................................ 15

5.10 Effective range of measurement ...................................................................................................... 15

5.11 Software and data analysis............................................................................................................... 16

6. Radiation detection and indication performance requirements................................................................. 17

6.1 Reference gamma-ray radiation......................................................................................................... 18

6.2 False alarms ....................................................................................................................................... 19

6.3 Response to gamma radiation............................................................................................................ 19

6.4 Response to neutron radiation ........................................................................................................... 20

6.5 Over-range......................................................................................................................................... 20

6.6 Neutron indication in the presence of photons .................................................................................. 21

6.7 Background effects ............................................................................................................................ 21

6.8 Radionuclide identification................................................................................................................ 21

6.9 Determination of full-energy-peak efficiency ................................................................................... 27

6.10 Determination of full width-half maximum (FWHM)..................................................................... 27

viii


7. Environmental performance requirements ............................................................................................... 28

7.1 Ambient temperature ......................................................................................................................... 28

7.2 Relative humidity .............................................................................................................................. 29

7.3 Moisture and dust protection ............................................................................................................. 30

8. Electromagnetic performance requirements ............................................................................................. 31

8.1 Electrostatic discharge (ESD)............................................................................................................ 31

8.2 Radio frequency (RF) susceptibility .................................................................................................. 31

8.3 Radiated emissions ............................................................................................................................ 32

8.4 Conducted disturbances induced by bursts and radio frequencies..................................................... 32

8.5 Magnetic fields .................................................................................................................................. 33

8.6 Surges and oscillatory waves............................................................................................................. 33

9. Mechanical performance requirements..................................................................................................... 34

9.1 Vibration............................................................................................................................................ 34

9.2 Microphonics/impact ......................................................................................................................... 34

10. Documentation ....................................................................................................................................... 35

10.1 Type test report................................................................................................................................ 35

10.2 Report .............................................................................................................................................. 35

10.3 Operation and maintenance manual................................................................................................. 36

Annex A (informative) Bibliography ........................................................................................................... 37

A.1 General.............................................................................................................................................. 37

A.2 Detectors........................................................................................................................................... 37

A.3 Detection and identification instruments .......................................................................................... 38

A.4 Radiological protection instruments ................................................................................................. 38

A.5 EMC.................................................................................................................................................. 38

A.6 Units, quantities, and calibrations..................................................................................................... 39

A.7 Security monitors.............................................................................................................................. 39

Annex B (informative) Diagram of mounting dimensions for radionuclide identifying portal monitors..... 40

ix





1. Overview

1.1

Scope

This standard specifies the operational and performance requirements for spectroscopy-based portal monitors used in U.S. Homeland Security applications. Spectroscopy-based portal monitors have the ability to detect radioactivity and identify radionuclides that may be present in or on persons, vehicles, or containers through the use of gamma spectroscopy techniques. Performance requirements for those portal monitors that do not provide information about the specific radionuclide present are addressed by ANSI

N42.35.

Operational requirements established by this standard include radiation detection and radionuclide identification, and those requirements associated with the expected electrical, mechanical, and environmental conditions when a monitor is deployed.

The test methods described in this standard provide a means to ensure that a monitor meets the requirements stated. Successful completion of the tests described in this standard should not be construed as an ability to successfully detect and identify all radionuclides in all environments.

This standard does not address portal monitors that may have the ability to reduce the effects caused by the presence of naturally occurring radioactive material (NORM) without the ability to identify specific radionuclides (see ANSI N42.35).

1

1.2

Purpose

The purpose of this standard is to specify the performance criteria and test methods for spectroscopy-based portal monitors used for Homeland Security.

1 The ANSI N42 publications included in this clause are available from the Institute of Electrical and Electronics Engineers,

445 Hoes Lane, Piscataway, NJ 08855-1331, USA (http://standards.ieee.org/).

1


ANSI N42.38-2006

American National Standard Performance Criteria for Spectroscopy-Based Portal Monitors Used for Homeland Security

1.3

General

1.3.1

Evaluation of monitors

Testing is conducted under a set of conditions to determine if a monitor meets the requirements of this standard. Special applications, which could include a monitor’s operation under weather conditions not addressed by this standard, shall require additional testing. Detection needs not addressed by this standard shall also require additional testing.

Evaluations provide information to government agencies and other users on the capability of radionuclideidentifying portal monitors for reliably detecting and identifying radioactive material.

1.3.2

Meeting performance specifications

Obtaining operating performance that meets or exceeds the specifications stated in this standard depends upon properly installing the monitor, establishing appropriate operating parameters, providing security for the systems, maintaining calibration, implementing a suitable routine testing and maintenance program, auditing compliance with quality requirements, and providing proper training for operating personnel.

2. Normative references

This standard shall be used in conjunction with the following publications. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies.

ANSI N42.22, American National Standard—Traceability of Radioactive Sources to the National Institute

2

of Standards and Technology (NIST) and Associated Instrument Quality Control.

ANSI N42.23, American National Standard Measurement and Associated Quality Assurance for

Radioassay Laboratories.

ANSI N42.34, American National Standard Performance Criteria for Hand-Held Instruments for the

Detection and Identification of Radionuclides.

ANSI N42.35, American National Standard for Evaluation and Performance of Radiation Detection Portal

Monitors for Use in Homeland Security.

ANSI N42.42, American National Standard Data Format Standard for Radiation Detectors Used for

Homeland Security.

3

ANSI/TIA-232-F-1997, Interface Between Data Terminal Equipment and Data Circuit-Terminating

Equipment Employing Serial Binary Data Interchange.

ANSI/TIA/EIA-485-A-98, Electrical Characteristics of Generators and Receivers for Use in Balanced

Digital Multipoint Systems.

4

FCC Rules, Code of Federal Regulations, Title 47, Part 15, Radio Frequency Devices.

2 The ANSI N42 publications included in this clause are available from the Institute of Electrical and Electronics Engineers, 445

3

Hoes Lane, Piscataway, NJ 08855-1331, USA (http://standards.ieee.org/).

4

The ANSI N42.42 schema can be obtained from http://physics.nist.gov/Divisions/Div846/Gp4/ANSIN4242/xml.html.

CFR publications are available from the Superintendent of Documents, U.S. Government Printing Office, P.O. Box 37082,

Washington, DC 20013-7082, USA (http://www.access.gpo.gov/).

2


ANSI N42.38-2006


IAEA Safety Guide No. RS-G-1.9, Categorization of Radioactive Sources.

5

IEC 60050-393 {Ed.2.0}, International Electrotechnical Vocabulary—Part 393: Nuclear instrumentation:

Physical phenomena and basic concepts.

6

IEC 60050-394, {Ed.2.0}, International Electrotechnical Vocabulary—Chapter 394: Nuclear instrumentation: Instruments.

IEC 60068-1, Environmental Testing—Part 1: General and Guidance.

IEC 60068-2-18, Environmental Testing—Part 2-18: Tests—Test R and Guidance: Water.

IEC 60068-2-75, Environmental Testing—Part 2-75: Tests—Test Eh: Hammer Tests.

IEC 60529, Degrees of Protection Provided by Enclosures (IP Code), IP54.

IEC 60721-4-4, Classification of Environmental Conditions—Part 4-4: Guidance for the Correlation and

Transformation of Environmental Condition Classes of IEC 60721-3 to the Environmental Tests of IEC

60068—Stationary Use at Non-Weatherprotected Locations.

IEC 61000-4-1,, Electromagnetic Compatibility (EMC)—Part 4-1: Testing and Measurement Techniques—

Overview of IEC 61000-4 Series..

IEC 61000-4-2, Electromagnetic Compatibility (EMC)—Part 4-2: Testing and Measurement Techniques—

Electrostatic Discharge Immunity Test.


Radiated, Radio-Frequency, Electromagnetic Field Immunity Test.


Electrical Fast Transient/Burst Immunity Test.


Surge Immunity Test.


Immunity to Conducted Disturbances, Induced by Radio-Frequency Fields.

IEC 61000-4-12, Electromagnetic Compatibility (EMC)—Part 4-12: Testing and Measurement

Techniques—Oscillatory Waves Immunity Test.


Techniques—Voltage Fluctuation Immunity Test.


Techniques—Variation of Power Frequency Immunity Test.

IEC 61455, Nuclear Instrumentation—MCA Histogram Data Interchange Format for Nuclear

Spectroscopy.

5

IAEA publications are available from the International Atomic Energy Agency, P.O. Box 100, Wagner Strasse 5, A-1400 Vienna,

Austria (http://www.iaea.org).

6

IEC publications are available from the Sales Department of the International Electrotechnical Commission, Case Postale 131, 3 rue de Varembé, CH-1211, Genève 20, Switzerland/Suisse (http://www.iec.ch/). IEC publications are also available in the United States from the Sales Department, American National Standards Institute, 11 West 42nd Street, 13th Floor, New York, NY 10036, USA

(http://www.ansi.org).

3


ANSI N42.38-2006


ISO/IEC 4037-3, X and Gamma Reference Radiation for Calibrating Dosemeters and Doserate Meters and for Determining the Response as a Function of Photon Energy—Part 3: Calibration of Area and Personal

Dosemeters and the Measurement of Their Response as a Function of Energy and Angle of Incidence.

7

Manual for Railway Engineering, American Railway Engineering and Maintenance-of-Way Association,

Mira Digital Publishing, Inc., 2003, Figure 28-1-3, page 28-1-5.

8

NEMA 250, Enclosures for Electrical Equipment (1000 Volts Maximum).

9

3. Definitions

The following definitions apply to this standard, as well as to ANSI N42.32 [B11], 10

ANSI N42.33 [B12],

ANSI N42.34 [B13], and ANSI N42.35, which have all been developed at the request of the U.S.

Department of Homeland Security (DHS) for instruments to be used by DHS and emergency responders.

3.1 General definitions

3.1.1 A-weighted sound level: The frequency weighting of an acoustic spectrum according to a standardized frequency response-curve based on the frequency response of the human ear.

3.1.2 acceptance test: Evaluation or measurement of performance characteristics to verify that certain stated speci fi cations and contractual requirements are met.

3.1.3 accepted ambient photon background: The background exposure rate as measured using a highpressure ionization chamber, an energy compensated Geiger-Mueller (GM) tube, an energy compensated proportional counter, a tissue equivalent plastic scintillator, a scintillator with spectral compensation, or any other exposure rate instrument having a nearly constant energy response (±30% in the energy range from

60 keV to 1.5 MeV).

3.1.4 accredited testing laboratory: Testing laboratory that has been accredited by an authoritative body with respect to its quali fi cations to perform veri fi cation tests on the type of instruments covered by this standard.

3.1.5 accuracy: The degree of agreement between the observed value with the conventionally true value of the quantity being measured.

3.1.6 adjust: To alter the reading of an instrument by means of a built-in variable (hardware or software) control.

3.1.7 alarm: An audible, visual, or other signal activated when the instrument reading or response exceeds a preset value or falls outside of a preset range.

3.1.8 calibrate: To adjust and/or determine the response or reading of a device relative to a series of conventionally true values.

7

ISO publications are available from the ISO Central Secretariat, Case Postale 56, 1 rue de Varembé, CH-1211, Genève 20,

Switzerland/ Suisse (http://www.iso.ch/). ISO publications are also available in the United States from the Sales Department,

American National Standards Institute, 11 West 42nd Street, 13th Floor, New York, NY 10036, USA (http://www.ansi.org/).

8

AREMA publications are available from AREMA, 10003 Derekwood Lane, Suite 210, Lanham, MD 20706-4362, USA

(http:www.arema.org).

9

NEMA publications are available from Global Engineering Documents, 15 Inverness Way East, Englewood, CO 80112, USA

(http://global.ihs.com/).

10

The numbers in brackets correspond to those of the bibliography in Annex A.

4


ANSI N42.38-2006


3.1.9 calibration: A set of operations under speci fi ed conditions that establishes the relationship between values indicated by a measuring instrument or measuring system and the conventionally true values of the quantity or variable being measured.

3.1.10 check source: A not-necessarily calibrated source that is used to con fi rm the continuing functionality of an instrument.

3.1.11 coefficient of variation (COV) (%): Ratio of the standard deviation, s, to the arithmetic mean , of a set of n measurements, x i

, given by the following formula: x ,

V

=

s x

=

1 x

∑

( x i n

−

−

1 x ) 2

3.1.12 conventionally true value (CTV): The commonly accepted best estimate of the value of that quantity.

NOTE—This and the associated uncertainty will preferably be determined by a national or transfer standard, or by a reference instrument that has been calibrated against a national or transfer standard, or by a measurement quality assurance (MQA) interaction with the National Institute of Standards and Technology (NIST) or an accredited calibration laboratory. (See ANSI N42.22 and ANSI N42.23.)

11

3.1.13 decade: A range of values for which the upper value is a power of ten above the lower value.

3.1.14 detection limits: The extremes of detection or quanti fi cation for the radiation of interest.

NOTE—The lower detection limit is the minimum statistically quanti fi able instrument response or reading. The upper detection limit is the maximum level at which the instrument meets the required accuracy.

3.1.15 detector: A device or component designed to produce a quanti fi able response to ionizing radiation normally measured electronically.

3.1.16 effective center: For a given set of irradiation conditions, the point within a detector where the response is equivalent to that which would be produced if the entire detector was located at the point.

3.1.17 effective range of measurement: Range of measurements within which the requirements of this standard are met.

3.1.18 energy dependence: Variation in instrument response as a function of radiation energy for a constant radiation type and exposure rate referenced to air.

3.1.19 exposure: The measure of ionization produced in air by x-ray or gamma-ray radiation.

NOTE—The special unit of exposure rate is the Roentgen per hour, abbreviated in this standard as R/h.

NOTE—In this standard, the International System (SI) units sievert (Sv) or gray (Gy) follow in parentheses the

Roentgen value R, though the two units are not physically equivalent.

3.1.20 false alarm: Alarm NOT caused by a radioactive source under the speci fi ed background conditions.

11

Notes in text, tables, and figures of a standard are given for information only and do not contain requirements needed to implement this standard.

5


ANSI N42.38-2006


3.1.21 functional check: A frequently used qualitative check to determine that an instrument is operational and capable of performing its intended function.

NOTE—Such checks may include, for example, battery check, zero setting, or source response check.

3.1.22 indicated value: (A) A scale or decade reading. (B) The displayed value of the readout. See also: reading .

3.1.23 indication: Displayed signal from the instrument to the user conveying information such as scale or decade, status, malfunction or other critical information.

3.1.24 in fl uence quantity: Quantity that may have a bearing on the result of a measurement without being the subject of the measurement.

3.1.25 innocent alarm: An alarm resulting from an actual increase in radiation level, but for reasons that are not due to the detection of illicit radioactive materials.

NOTE—Also known as nuisance alarm.

3.1.26 instrument: A complete system consisting of one or more assemblies designed to quantify one or more characteristics of ionizing radiation or radioactive material.

3.1.27 instrument hour: The number of operating instruments multiplied by the amount of time they are operating (e.g. 8 instruments operating for 3.75 h is equivalent to 30 instrument hours).

3.1.28 interdiction: Stopping the illicit or inadvertent movement of radioactive material that has been discovered as a result of radiation detection or measurement.

3.1.29 monitoring: Means provided to continuously indicate the state or condition of a system or assembly.

NOTE—May also be used for the real time measurement of radioactivity or exposure rate.

3.1.30 overload response : See : over-range response.

3.1.31 over-range response: The response of an instrument when exposed to radiation intensities greater than the upper measurement limit. Syn : overload response .

3.1.32 performance test: An evaluation of the performance of an instrument in response to a given in fl uence quantity.

3.1.33 point of measurement: Place where the conventionally true values are determined and where the reference point of the instrument is placed for test purposes.

3.1.34 precision: Degree of agreement of repeated measurements of the same parameter.

3.1.35 range: All values lying between the lower and upper detection limits.

3.1.36 reading: The indicated or displayed value of the readout.

3.1.37 readout: The portion of the instrument that provides a visual display of the response of the instrument or the displayed value, with units, displayed and/or recorded by the instrument as a result of the instrument’s response to some in fl uence quantity.

6


ANSI N42.38-2006


3.1.38 reference point of an instrument: Physical mark, or marks, on the outside of an instrument used to position it at a point where the conventionally true value of a quantity is to be measured, unless the position is clearly identi fi able from the construction of the instrument.

3.1.39 relative error [ multiplied by 100.

ε

REL

(%)]:

The difference between an instrument’s reading, M , and the conventionally true value, CTV , of the quantity being measured divided by the conventionally true value

ε

REL

(%)

= [(M – CTV)

⁄

(CTV)] × 100

3.1.40 response: Ratio of the instrument reading to the conventionally true value of the measured quantity.

3.1.41 response time: The time interval required for the instrument reading to change from 10% to 90% of the fi nal reading or vice versa, following a step change in the radiation field at the detector.

3.1.42 restricted mode: An advanced operating mode that can be accessed by an expert user (e.g., via password) to control the parameters that can affect the result of a measurement (e.g.,radionuclide library, routine function control, calibration parameters, alarm thresholds).

NOTE—May be called the “advanced” or “expert” mode.

3.1.43 routine test: Test that applies to each independent instrument to ascertain compliance with speci fi ed criteria.

3.1.44 standard deviation: The positive square root of the variance.

3.1.45 standard instrument or source: (A) National standard—a standard determined by a nationally recognized competent authority to serve as the basis for assigning values to other standards of the quantity concerned. In the U.S., this is an instrument, source, or other system or device maintained and promulgated by the National Institute of Standards and Technology (NIST). (B) Primary standard—a standard that is designated or widely acknowledged as having the highest metrological qualities and whose value is accepted without reference to other standards of the same quantity. (C) Secondary standard—a standard whose value is assigned by comparison with a primary standard of the same quantity. (D) Reference standard—a standard, generally having the highest metrological quality available at a given location or in a given organization, from which measurements made there are derived. (E) Working standard—a standard that is used routinely to calibrate or check material measures, measuring instruments, or reference materials. A working standard is traceable to NIST (see ANSI N42.22 and ANSI N42.23).

3.1.46 standard test conditions: The range of values of a set of in fl uence quantities under which a calibration or a measurement of response is carried out.

3.1.47 test: A procedure whereby the instrument, circuit, or component is evaluated.

3.1.48 type test: Initial test of two or more production instruments made to a speci fi c design to show that the design meets de fi ned speci fi cations.

3.1.49 uncertainty: The estimated bounds of the deviation from the conventionally true value, generally expressed as a percent of the mean, ordinarily taken as the square root of the sum of the square of two components: 1) Random errors that are evaluated by statistical means; and 2) systematic errors that are evaluated by other means.

3.1.50 upper measurement limit (UML): The UML is the maximum level at which the instrument meets the required accuracy.

7


ANSI N42.38-2006


3.1.51 variance ( σ 2 ): A measure of dispersion, which is the sum of the squared deviation of observations from their mean divided by one less than the number of observations.

=

n

1

−

1 i n

∑

= 1

( x i

−

x

)

2

σ

2

3.2 Definitions of particular relevance to ANSI N42.38

3.2.1 acceptable identification: When a monitor identifies the radionuclide(s) of interest or that radionuclide(s) and expected daughter(s), and no others.

3.2.2 alarm assembly: Equipment designed to indicate visually, audibly, or both, that the measured material has generated an alarm.

3.2.3 alarm criteria: Conditions that cause a monitor to alarm.

NOTE—For portal monitors without the ability to identify radionuclides, alarm threshold settings are typically based on the gamma-ray or neutron count rates obtained during an occupancy or measurement cycle and also the ambient background. Spectroscopy-based portal monitors also have the ability to activate or not activate an alarm based on the identified radionuclide(s) as desired by the user.

3.2.4 confidence indication: An indication provided by the monitor of the reliability assigned to the determined identification.

3.2.5 detection assembly: The monitor enclosure that includes the detector, the associated electronics and the mounting components.

3.2.6 detection zone: The region that is either located between opposing detection assemblies or adjacent to a detection assembly over which the detection requirements are satisfied.

NOTE—Annex A shows a diagram of the detection zone.

3.2.7 efficiency: the net number of counts registered by the detector per unit time divided by the number of photons of interest originating from the radioactive source that is being measured during the same unit of time.

3.2.8 evaluation distances: The distance between an evaluation test source and the exterior face(s) of the detection assembly(s).

3.2.9 full width at half maximum (FWHM): The full width of a distribution measured at half the maximum ordinate.

3.2.10 local: Within close proximity to the detection assembly(s).

3.2.11 manufacturer: Includes the designer of the equipment.

3.2.12 NORM: Naturally-occurring radioactive material.

3.2.13 occupancy: When the detection zone is occupied with an object (person, vehicle, package, etc.) that is being monitored.

8


ANSI N42.38-2006


3.2.14 portal monitor: A radiation measurement device designed to detect changes in the measured exposure rate as an object passes through or is placed in an area that is adjacent to a radiation detection assembly or assemblies.

3.2.15 purchaser: Includes the user of the equipment.

3.2.16 radioactive material: In this standard, radioactive material includes special nuclear material unless otherwise specifically noted.

3.2.17 reference point of the detection zone: The reference point of the detection zone is that point that is at the center of the detection zone in both axes (horizontal and vertical) at a distance from the detection assembly based on the monitor type given by the evaluation distance (see Table 1). The z-axis or depth position is determined based on the width (related to object flow) of the detection assembly.

3.2.18 remote station: A computing system or subsystem used for data archiving, control, annunciation, printing, or other functions for portal monitor assemblies, typically located at a distance from the portal monitors.

3.2.19 spectroscopy-based portal monitor: A portal monitor that uses gamma spectroscopy techniques for the identification of radionuclides.

3.2.20 standard test sources: A set of NIST-traceable radiation sources required to perform an evaluation.

4.

General considerations

All tests are to be considered type tests unless otherwise speci fi ed in an individual step. If the manufacturer claims a broader range of operation (for example, an operating temperature range of − 30 °C to +55 °C) and the user requires this range, then additional testing and verification should be agreed upon between the manufacturer and customer. Certain tests may be considered as acceptance tests by agreement between the customer and manufacturer.

4.1

Standard test conditions

Except where otherwise speci fi ed, the tests in this standard shall be carried out under the standard test

conditions shown in Table 4.

For those tests intended to determine the effects of variations in the in fl uence quantities, all other in fl uence

quantities should be maintained within the limits for standard test conditions given in Table 4 unless other-

wise speci fi ed in the test procedure concerned.

4.2

Units and uncertainties

For the purposes of this standard, the radiological units of exposure rate (R/h) shall be used for x-ray and gamma-ray radiation. Exposure rate can be converted to air-kerma rate by using the following conversion factor: 1R/h = 876 mrad/h (8.76 mGy/h).

For x-rays and gamma-rays the factor to convert from absorbed-dose-to-tissue (rad) to dose equivalent

(rem) is equal to 1. Therefore, in conventional units 1 rad = 1 rem and in SI units 1 Gy = 1 Sv. Conversion coefficients can be used to convert from air-kerma to dose equivalent. The conversion coefficients are tabulated as a function of photon energy as described in ISO/IEC 4037-3.

9


ANSI N42.38-2006


Throughout the text, radiological quantities are expressed in conventional units; SI units are given in parentheses.

If uncertainties are not specified they shall be set to ± 5%.

4.3

Special word usage

The following word usage applies:

⎯ The word “shall” signi fi es a mandatory requirement (where appropriate, a qualifying statement is included to indicate that there may be an allowable exception).

⎯ The word “may” signi fi es an acceptable method or an example of good practice.

⎯ The word “should” signi fi es a recommended speci fi cation or method.

5. Design requirements

5.1

General characteristics

The equipment addressed by this standard shall detect changes in exposure rates and identify radionuclide(s) in objects, containers, vehicles, or pedestrians when the signal from the detection system meets an alarm condition (exposure rate or identification results). Measurement occurs when an object passes through the detection zone or with an object stationary within the detection zone where the user performs controlled analyses of the object (i.e., enters collection time and activates the count).

Monitors shall be capable of operating independently of any peripheral device or remote station and shall be unaffected by any malfunction of a peripheral device.

The monitor shall be able to operate for up to 3 h if there is a loss of external power and/or data transfer capabilities to the remote station. Operations shall include storing measurement data at the monitor.

According to their use, spectroscopy-based portal monitors are classified as follows:

⎯ Pedestrian

⎯ Package (e.g., conveyor)

⎯ Vehicle (including containerized cargo)

⎯ Rail vehicle

The detection zone is the area located adjacent to, or between, one or more detection assemblies where the measurement of radiation takes place. The size of the detection zone is based on the classification of use. If a monitor is used in two or more classifications, its associated detection zone shall be appropriate for each classification.

The monitor shall meet the performance requirements of this standard when installed as tested. Operational conditions such as separation distance and background radiation shall be considered when installing a radionuclide-identifying portal monitor. The manufacturer shall state the distances at which the monitor meets this standard, if the distances are different than those stated in the document.

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ANSI N42.38-2006


The reference point of the detection zone is located at the evaluation distance listed in Table 1 and centered

in both the height and width orientations of the detection zone.

Table 1 —Evaluation distances for different applications

Monitor type Distance between detection assemblies

Evaluation distance

Single-sided vehicle monitors (includes containerized cargo)

N/A Source 5 m from assembly

Multiple sided vehicle monitors (includes containerized cargo)

Single-sided pedestrian or package monitors

Monitors 5 m apart measured from the surface of each detection assembly.

N/A

Centered between detection assemblies

Fixed dimension pedestrian or package monitors N/A

Source 1 m from detector


Multiple sided pedestrian or package monitors

Single-sided rail vehicles monitors


N/A


Source 6 m from assembly

Multiple-sided rail vehicle monitors



5.1.1

Pedestrian

Pedestrian monitors shall provide a detection zone to ensure that people are monitored. As a minimum, the range of the detection zone shall be from 0.1 m to 2 m above the ground. The recommended distance

between detection assemblies for evaluation purposes is listed in Table 1 or if fixed, is given by the

manufacturer.

Pedestrian monitors may use a single detection assembly (single-sided) or multiple opposing detection assemblies with or without detectors across the top and/or bottom part of the detection assembly. For monitors with a restricted passage height, the height of the detection zone shall be from the ground or base surface to the top surface of the monitor’s detector.

The passage or transit speed for testing shall be the speed listed in Table 2.

Table 2 —Speed of moving sources

Monitor type

Vehicle monitors (except rail)

Source speed

8 km/h

Occupancy time for test

5 s

Pedestrian monitors

Package or conveyor monitor

Rail vehicle monitors

1.2 m/s

1.2 m/s

8 km/h

1 s

1 s

5 s

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ANSI N42.38-2006


5.1.2

Vehicle (includes road-transported containers)

Vehicle monitors shall provide a detection zone that ensures that the entire vehicle is monitored during passage. As a minimum, the range of the detection zone shall be from 0.2 m to 4.5 m above ground. For monitors with a restricted passage height, the height of the detection zone shall be from 0.2 m to the top surface of the monitors’ detector. The distance between vertical monitors for evaluation purposes is listed

in Table 1 or provided by the manufacturer if the monitor is an assembly that has the detection assemblies

at a fixed distance apart.

The passage speed for testing shall be the speed listed in Table 2.

5.1.3

Rail vehicle (includes rail-transported containers)

Rail vehicle monitors shall provide a detection zone that ensures that the entire rail vehicle is monitored during passage. As a minimum, the range of the detection zone is from 0.3 m to 6 m above the rail (For test purposes, the ground surface should be considered as the top of the rail). (See ANSI N42.35.) For monitors with a restricted passage height, the range of the detection zone shall be from 0.3 m to the top surface of the

monitors’ detector. The distance between vertical monitors for evaluation purposes is listed in Table 1 or, if

fixed, is given by the manufacturer.


5.1.4

Package (or conveyor monitor)

Package or conveyor monitors shall provide a detection zone that ensures that items moving through the detection zone are monitored. Monitors may use a single detection assembly (single-sided) or multiple opposing detection assemblies which may have detectors across the top and/or bottom part of the detection assembly (multi-sided).

As a minimum, the height of the detection zone shall be either (1) from the base surface to 1 m above the base surface (that surface which corresponds to the ground or conveyor bottom surface) for detectors mounted below the base surface, or (2) from the base surface to the face of the detection assembly for detectors mounted 1 m above the base surface. For monitors with a restricted passage height, the range of the detection zone shall be from the base surface to the manufacturer-stated height.


5.2

Physical configuration

Enclosure(s) provided for outdoor assemblies shall be designed to meet IP54 classification as designated in

IEC 60529. Vent holes are permitted if required by the manufacturer.

The detection assemblies for road and rail vehicle monitoring may be subjected to vibration. Monitors and installation techniques (e.g., concrete pads, support brackets) shall be designed to prevent normal vibrations and shocks from interfering with the operation of the detection system.

Controls and adjustments which affect calibration and alarm settings shall be designed so that access to them is limited to authorized people.

Provisions shall be made to permit testing of visual and/or sound warning indicators without the use of radiation sources.

Detector response evaluations shall be performed without the benefit of any radiation shielding against the natural background, except for that shielding which is a permanent feature of the monitor or if it is required for a specific test.

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ANSI N42.38-2006


5.3

Spectral identification

a) b)

A displayed gamma-ray spectrum is not required during routine operation. The spectrum display shall be available by manufacturer-defined user actions.

The monitor shall have the ability to internally store at least 1000 complete occupancy data sets.

For monitors that do not use occupancy sensors, the monitor shall have the ability to store 3 h of measurement data as defined in item c). c)

2)

3)

4)

5)

Each occupancy data set shall contain collection and identification results information including:

1) Unprocessed spectrum (spectra for multi-detector systems) obtained during a single occupancy

Time and date

Real time for alarm spectrum

Run time for alarm spectrum

Identified radionuclides, categories, and confidence level (if available)

6)

7)

8)

9)

Occupancy time

Monitor identification

Alarm condition (gamma-ray and/or neutron)

Background (gamma-ray and neutron) count rate and spectrum (includes real time and run time)

10) Gamma-ray count rate

11) Neutron count rate

12) Vehicle speed (if available)

The data format shall comply with ANSI N42.42 requirements. d) The monitor shall have the ability to store background count rate and spectra, and transfer that information at user selectable intervals to an external device, such as a computer. e) f) g) h)

The monitor shall have the ability to store gamma-ray and neutron count rate time-history data.

An indication shall be displayed or otherwise provided (e.g., “not identified”) if a radionuclide cannot be identified when or after a measurement takes place.

If a reliability or confidence level is associated with the identification of a radionuclide(s), the confidence level shall be provided in the data set and the manufacturer shall describe the meaning of the displayed value.

The monitor shall have the ability to perform identification measurements with an object stationary in the detection zone. This function shall be user selectable and does not supersede

the requirements stated in 6.8. The recommended measurement time shall be stated by the

manufacturer and should be less than or equal to 1 min.

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ANSI N42.38-2006


5.4

Indication features

The monitor shall provide an indication of its operational status and alarm condition, and shall be capable of transmitting these signals to additional remote stations. The user shall have the ability to select the visibility of the status indication.

All alarm indicators shall automatically or manually reset as defined by the user.

5.5

Occupancy and speed sensors for vehicle monitors

Monitors shall have the ability to support occupancy sensors and should have the ability to measure speed.

If used, occupancy and speed sensors:

⎯ Shall be able to detect presence and estimate vehicle speed, indicate if a vehicle stops within the detection zone, and not count a single vehicle or object in the detection zone more than once

⎯ Should be capable of operating on a mix of traffic (e.g., cars, vans, pickup trucks, buses, cargo trucks, trains)

⎯ Should function under all environmental conditions stated in this standard

Rail monitors should have the ability to approximate the location of an alarm when monitoring multi-car trains.

For test purposes, a system that incorporates an occupancy sensor should have the ability to perform a userselected series of consecutive occupancies automatically without the need to activate the occupancy sensor.

Function variables such as occupancy time and time between occupancies shall be user-selectable.

5.6

Markings

Internal controls shall be identified by markings on electrical circuit boards and/or individual components, and identification in technical manuals.

Markings shall be permanently fixed under normal conditions of use.

Exterior markings shall be limited to the manufacturer’s unique serial number, voltage and current requirements, if equipped with an outlet plug, and shall meet minimum applicable municipal, state, federal, and international code requirements.

5.7

Power supply

5.7.1

Requirement

Line-operated assemblies should be designed to operate from a single-phase AC supply voltage of 100 V to

240 V and from 47 Hz to 63 Hz.

The monitor shall be able to operate, including storing measurement data for a minimum of 3 h, if there is a loss of external power. Compliance shall be based on tests performed at the reference temperature of 22 ° C.

See also 5.8.

14


ANSI N42.38-2006


5.7.2

Test method

Place the 137 Cs and 252 Cf test sources in a location that provides a stable response. With the supply voltage at its nominal value, determine the mean gamma-ray and neutron readings from a sufficient series of readings and perform a ten-trial radionuclide identification of trials.

137 Cs. Record the results as x correct for ten

Increase the supply voltage to 12% above the nominal value. Determine and record each channel’s mean reading and perform a ten-trial radionuclide identification using 137 Cs. Decrease the supply voltage to 12% below the nominal value and again determine and record the mean readings, and perform a ten-trial radionuclide identification

Repeat the previous tests at the nominal supply voltage with the line frequency at 3% above and 3% below the nominal frequency (58 Hz to 62 Hz).

For this test, the results from each voltage or frequency test point from each series of identifications shall be the same or better than the identification results obtained at the nominal voltage and frequency. For example, if the ten trial results at nominal voltage and frequency are correct in six out of ten trials, the results at each test point shall be six or more correct to be acceptable. For the gross response channels, the results are acceptable if the mean readings obtained at each voltage or frequency test point are within ±15% of the mean readings obtained at the nominal voltage and frequency.

5.8

Battery life-time

5.8.1

Requirement

Monitors shall be able to operate including storing measurement data for up to 3 h if there is a loss of external power.

5.8.2

Test method

Monitors shall be placed under standard test conditions, switched on, and allowed a stabilization and background detection period as speci fi ed by the manufacturer.

Disconnect the AC line, and using only 133 Ba(g), perform an occupancy at 10 s intervals following the

guidance found in step 6.3 with the source passing through the mid-point of the detection zone at the speed

appropriate for the monitoring system being tested. Perform the test for 3 h.

To be acceptable, the monitor shall perform within specifications for the entire 3 h period and shall have stored all the required information from each occupancy. The low-battery indication shall not have activated during the period.

5.9

Protection of switches

Switches and other controls should be designed to ensure that the monitor can be operated properly while minimizing accidental switch operation.

5.10

Effective range of measurement

The effective gamma-ray energy response range shall be stated by the manufacturer, and should be at least

25 keV to 3 MeV. The manufacturer shall state the range for gamma-ray count rate measurement and for neutron count rate indication.

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ANSI N42.38-2006


5.11

Software and data analysis

5.11.1

Communications protocol and data format

The monitor shall have the ability to transfer data to an external device, such as a computer. The transfer shall be based on a commonly available technology such as Ethernet, USB, RS-232, wireless (e.g., 802.11), or RS-485. Consideration should be given to data security when using wireless data transfer techniques.

When used, wireless techniques shall have the ability to be encrypted.

The transfer protocol and format shall be fully described in the technical manual and shall also be freely distributable.

Data format shall be as defined in ANSI N42.42.

5.11.2

User interface

5.11.2.1

Visual indicators

The monitor should provide a color-based visual indication for the following actions:

Alarm color Type

Blue

Orange

SNM identification and user-selectable high-radiation alarms

Other gamma-ray alarms (e.g., NORM)

White Checking

5.11.2.2 Warning indicators

The following indications shall be provided at the user interface as a minimum.

⎯ Background changes during non-occupancies that can affect the overall sensitivity of the monitor

⎯ High-low detector count rate conditions

⎯ Energy stabilization invalid or not acceptable

⎯ Occupancy sensor failure, if occupancy sensors are used

⎯ Changes in operational status (e.g., occupied, alarm, monitoring background, fault, blocked)

⎯ Loss of line power

⎯ Battery status

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ANSI N42.38-2006


5.11.2.3

Basic indications and functions

The following information and control shall be provided for the trained user.

⎯ View operational status

⎯ View alarm indication

⎯ Ability to reset alarms

⎯ View identified radionuclide(s) (user selectable through advanced or supervisory access)

5.11.2.4

Advanced indications and functions

The following information and control shall be provided for the supervisory user through the use of access controls or special commands.

⎯ Access to and control of operating parameters (radionuclide library, alarm control)

⎯ Access to and control of data logging intervals

⎯ Access to alarm history

⎯ Access to spectra

⎯ Access to radionuclide identification results and control of basic indication function

⎯ Access to occupancy data set (if occupancy sensors are used)

⎯ Access to vehicle photo (if available)

⎯ Access to radiation profiles (count-rate, time-history data)

⎯ Access to background radiation information

⎯ Access to alarm selection criteria including the ability to select specific radionuclides

⎯ Access to status indication criteria including the ability to set the exposure rate for activation of the high radiation indicator

⎯ Access to energy and/or efficiency calibration information

6.

Radiation detection and indication performance requirements

CAUTION

When performing tests with radiation sources, actions shall be taken to ensure that when the monitor is measuring background, no additional radiation is present that can alter the ambient background. For

example, when performing the repetitive tasks described in Clause 6, after each pass through the detection

zone, the radiation source shall be shielded or moved to a distance that will ensure that the background is unaffected between each pass or occupancy.

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ANSI N42.38-2006


6.1

Reference gamma-ray radiation

Unless otherwise stated, tests requiring the collection of only the non-spectroscopic gamma-ray response shall be carried out using the reference gamma radiation,

specified in Table 3.

252

137 Cs (see ISO 4037-3), at the activity value

Cf is used for neutron response testing. Other reference radionuclides are listed in

Table 3. Note that the measured gamma-ray emissions from

encapsulation.

252 Cf are reduced by the stainless steel

The activity levels chosen are for testing only and are not indicative of the alarm set point or overall sensitivity of the monitoring system, which are established based on the ambient background and acceptable false alarm rate.

Table 3 —Activity values for gamma-ray and neutron sources

(1) (2)

Radionuclide

Activity (µCi) unshielded (4)

Activity (µCi) steel shielded

(3 cm) (4)

Activity (µCi) poly shielded (4) (5)

241 Am 47 — —

133 Ba(i) 9 148 —

133 Ba(g) 3 — —

57 Co(i) 15 — —

57 Co(g) 5 — —

60 Co 7 25 —

137 Cs 16 85 —

DU (6) 4.5 kg (46 cm 2 ) — —

67 Ga 16 — 94

HEU (6) 237 g (6.5 cm 2 ) — —

131 I 10 — 23

192 Ir 6 61 —

40 K 128 — —

237 Np (6)

90 mg with 1 cm Fe shielding

— —

99m Tc 16 — 127

201 Tl 10 — 88

226 Ra 8 — —

232 Th

RGPu

WGPu

252 Cf

(6)

(6)

(3)

14 — —

1.4 g with 1 cm Fe shielding

15 g with 1 cm Fe shielding

2 × 10 4 n/s ± 20%

— —

— —

— —

(1) – Values stated are based on calculations performed using published information available at the time of drafting, and are based on photon emission rates using those photons with energies greater than 25 keV with the radioactive material contained in a 0.25 mm stainless steel encapsulation. An emission rate of 500000 gamma-rays per second was used as a basis. This was determined using the approximate emission rate of 137 Cs for an exposure rate of 5 µR/hr at 1 m.

(2)

- The actual activity of each source at the time of testing shall be not more than 20% greater than the value shown in Table 3. The

uncertainty in the actual activity value shall be less than 10% (1 σ ). All sources activities shall be traceable to NIST.

(3)

(4)

- The neutron source is encapsulated in 1 cm steel and 0.5 cm lead.

– Unless otherwise stated (see note 6), the shown mass values are based on a total gamma-ray leakage of 500,000 gammarays/second at energies greater than 40 keV.

(5)

(6)

– “Poly” = polymethyl methacrylate.

– The amounts of HEU and DU are stated in terms of cross-sectional area as well as the mass of solid spheres. This is because these sources are surface emitters and the cross-sectional area determines the flux. WGPu, RGPu, and 237 Np are shielded with 1 cm Fe for handling purposes due to ES&H issues and for particularly Pu, they emit quite a few low-energy gamma rays that do not contribute to the ability to identify the isotopes. 20-years age is used as a basis for the transport calculations.

18


ANSI N42.38-2006


6.2

False alarms

NOTE 1— False alarms and misidentifications can be caused by inadequate counting statistics, background intensity variations, and/or equipment malfunction. Gross-count rate capabilities are generally adjusted using alarm thresholds that interrelate overall sensitivity and false alarm rates.

NOTE 2— This requirement contains two parts—false gross counting alarms and false identifications—that may be performed simultaneously.

6.2.1

Requirement

When tested in an area with a stable background (only natural fluctuations) at the levels stated in Table 4,

the false alarm rate shall be less than 1 per 1000 occupancies for systems that use occupancy sensors or one alarm over a 2 h time period for monitors that do not use occupancy sensors. In addition, the monitor shall not identify a radionuclide that is not present during the test period.

Table 4 —Standard test conditions

Influence quantity

Ambient temperature

Standard test conditions (unless otherwise indicated by the manufacturer)

18 o C to 25 o C

Relative humidity 20 % to 75 %

Atmospheric pressure

70 kPa to 106.6 kPa (525 to 800 mm of mercury at 0 °C)

Electromagnetic field of external origin Negligible

Magnetic induction of external origin Negligible

Monitor controls Set up for normal operation

Background exposure rate

Reference photon radiations

Reference neutron radiation

<25 uR/hr

See Table 3

252 Cf

6.2.2

Test method

The test shall be performed with a minimum of 1000 occupancies using a 5 s integration time or observe the monitor for 2 h in an area that has a stable and controlled background. The results are acceptable if no more than 1 alarm occurs and there are no false identifications.

6.3

Response to gamma radiation

NOTE—This test provides information about the gross counting capabilities of the system. This function is separate

from the identification requirement that is described in 6.8.

19


ANSI N42.38-2006


6.3.1

Requirement

A monitor shall alarm when gamma-ray exposure rate (i.e., overall count rate) measured as an object

transits through the detection zone at the speed stated for that specific application (see Table 2) is greater

than the alarm setting. The monitor shall alarm a minimum of 49 times in 50 occupancies. The visual

indication shall be activated as defined in step 5.11.2.1.

6.3.2

Test method

NOTE—Table 3 contains two

133 are used for the following test.

Ba sources (see ISO4037-3) and two

133 Ba(i) and 57

57 Co sources. The 133 Ba(g) and 57 Co(g) sources

Co(i) are used for the identification tests described in 6.8.2 and 6.8.3.

Note that “g” is used to define those sources used for gross response testing and “i” for identification testing.

Using 133 Ba(g) and 57

Co(g) (see Table 3), pass each source horizontally through the detection zone at the

required test speed through the bottom, middle, and top of the detection zone, and the mid-point between the middle and bottom, and middle and top planes. There shall be a 10 s delay between each trial with the source either positioned at a distance where it does not affect the background or shielded during the delay.

6.4

Response to neutron radiation

6.4.1

Requirement

A monitor shall alarm when the neutron exposure rate (i.e., count rate) measured as an object transits

through the detection zone at the speed stated for that specific application (see Table 2), is greater than the

alarm setting.

The monitor shall alarm a minimum of 49 times in 50 occupancies. The visual indication shall be activated

as defined in step 5.11.2.1.

6.4.2

Test method

Using the neutron source from Table 3, verify that the monitor alarms when passing the source through the

detection zone at the required transit speed at the application-specific distance from the detection assembly(s). The transit heights shall be based on the application and are the bottom, middle, and top of the detection zone, and the mid-point between the middle and bottom, and middle and top planes.

6.5

Over-range

6.5.1

Requirement

If a monitor is subjected to an exposure rate that is greater than the manufacturer-stated maximum during an occupancy or when performing measurements without an occupancy sensor, an alarm indicating, for example “high background” or “high counts,” shall be activated and shall remain activated until the exposure rate is reduced or the alarm is reset/acknowledged by the user. The visual indication for the user-

selectable high radiation alarm shall be activated as defined in step 5.11.2.1.

The time required to return to non-alarm condition after the exposure rate is returned to background shall be not greater than 1 min.

20


ANSI N42.38-2006


6.5.2

Test method

Initiate a monitoring cycle with the monitor operating in a stable background. Simultaneously, using 137 Cs increase the ambient background by a minimum of 10 mR/h as measured at the reference position of the detection zone. The monitor shall alarm and remain in alarm until the exposure rate is reduced to the pretest level. Within 1 min of the removal of the source, the monitor shall return to the pre-test count rate.

The system shall alarm and recover successfully in three successive tests.

6.6

Neutron indication in the presence of photons

6.6.1

Requirement

Gamma radiation at exposure rates of up to 10 mR/h (at the face of the center of the detection assembly) shall not trigger the neutron alarm.

6.6.2

Test method

Using 60 Co, increase the ambient gamma-ray exposure rate by 10 mR/h for a period of 5 s as measured at the center of the surface of the detection assembly while the monitor is occupied. Remove the radiation source and allow the monitor to return to normal operation and repeat the test for a total of three trials.

Immunity of neutron detectors to gamma radiation is confirmed if no neutron alarms are triggered with the alarm set point at the value used for the neutron alarm test.

6.7

Background effects

6.7.1

Requirement

The monitor shall provide a warning indication when a change in background is large enough to cause a substantial change in alarm probability. The indication shall be visual and audible and shall be different than monitoring alarms.

6.7.2

Test method

Without triggering an occupancy (if occupancy sensors are used), move the Table 3

137 Cs source starting from at least 8 m away from the center of the detection zone at a speed of 0.08 km/h towards and eventually through the detection zone, or until a point where the monitor indicates that the background has changed substantially. Repeat the process two additional times for a total of three trials. The time interval

between each trial shall be 1 min. Repeat the entire process using the Table 3

shall indicate that the background has changed for each trial.

252 Cf source. The monitor

6.8

Radionuclide identification

NOTE—When testing the identification capabilities of spectroscopy-based portal monitors, the monitor shall identify the radionuclide(s) of interest or that radionuclide(s) and expected daughter(s), and no others. If naturally occurring radionuclides such as 40 the test.

K are identified, actions should be taken to reduce or eliminate the source prior to continuing

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ANSI N42.38-2006


6.8.1

Radionuclide categorization

NOTE—IAEA Safety Guide No. RS-G-1.9 contains a list of radionuclides and categories. This is an informative list and should not be considered as all-inclusive.

⎯ Special nuclear materials: Uranium (used to indicate 233 U, 235 U), 237 Np, Pu

⎯ Medical radionuclides: 18 F,

153 Sm, 201 Tl, 133 Xe

67 Ga, 51 Cr, 75 Se, 89 Sr, 99 Mo, 99m Tc, 103 Pd, 111 In, Iodine ( 123 I, 125 I, 131 I),

⎯ Naturally occurring radioactive materials (NORM): 40 daughters

K, 226 Ra, 232 Th and daughters, 238 U and

⎯ Industrial radionuclides: 57 Co, 60 Co, 133 Ba, 137 Cs, 192 Ir, 204 Tl, 226 Ra, and 241 Am

6.8.1.1

Requirement

The manufacturer shall state the radionuclides that the monitor can identify and their category. The

categories selected should be based on the list shown in 6.8.1. The following tests shall be performed based

on the manufacturer-provided list.

6.8.1.2

Test method

Verify that the requirement is met by review of manufacturer’s provided information.

6.8.2

Single radionuclide identification

NOTE 1— Identification ability is tested using source activities determined from photon emissions that are greater than

25 keV, taking into consideration encapsulation and shielding as described in Table 3.

NOTE 2— The emission rate used as a basis to determine each stated activity, 500 000 gammas per second, is approximately equivalent to an exposure rate of 5 μ R/hr from a 0.25 mm stainless steel encapsulated 137 distance of 1 m.

Cs source at a

6.8.2.1

Requirement

The manufacturer shall provide a list of radionuclides that the monitor can identify. The list should contain as a minimum, the following radionuclides:

⎯ 40 K, 57 Co, 60 Co, 67 Ga,

Reactor Grade Plutonium (RGPu),

Plutonium (WGPu), 237 Np

99m Tc, 131 I, 133 Ba, 137 Cs, 192 Ir, 201 Tl, 226 Ra, 232 Th, depleted uranium (DU),

241 Am, Highly Enriched Uranium (HEU), Weapons Grade

If the manufacturer claims the ability to detect HEU, RGPu, or WGPu, perform the methods discussed in

6.8.2.3. If no such claims are made, step 6.8.2.3 is not required.

22


ANSI N42.38-2006


6.8.2.2

Test method—unshielded

NOTE—There are two different 133 Ba and 57

Co sources listed in Table 3.

133 Ba(i) and 57 Co(i) are used for the test shown in this subclause. The term “i” indicates sources used for identification and “g” for those sources used for gross alarm testing.

The monitor shall identify the following radionuclides, or at least those stated by the manufacturer at the reference speed for that specific application, or measurement cycle time as stated by the manufacturer:

⎯ 40 K, 57 Co, 60 Co, 67 Ga, 99m Tc, 131 I, 133 Ba, 137 Cs, 192 Ir, 201 Tl, 226 Ra, 232 Th, DU, 241 Am

For transitory measurements, pass each source through the detection zone horizontally at the required test

speed at the application-specific distance (see Table 1). The transit heights shall be based on the application

and are the bottom, middle, and top of the detection zone and the mid-point between the middle and

bottom, and middle and top planes. Source activities are shown in Table 3.

NOTE—The following paragraph provides guidance for performing the test with the source stationary within the detection zone.

For stationary measurements, manually start a measurement cycle with each source positioned in the

horizontal center of the detection zone at the application-specific distance (see Table 1). The heights shall

be based on the application and are the bottom, middle, and top of the detection zone and the mid-point between the middle and bottom, and middle and top planes. As in the transitory measurements, source

activities are shown in Table 3.

The test for either transitory or stationary measurements shall consist of ten consecutive trials for each radionuclide in each configuration as required for that monitor’s application. The monitor’s alarm shall be reset between each trial, if appropriate. There shall be a 10 s delay between each trial with the source either positioned at a distance where it does not affect the background or shielded during the delay.

The performance is acceptable when the monitor correctly identifies the radionuclide in eight out of ten

consecutive trials and the visual indication for other gamma-ray sources as defined in step 5.11.2.1 is

activated for each alarm.

NOTE—It is not necessary to validate the identification of non-listed radionuclides.

6.8.2.3

Test method—unshielded SNM

NOTE—For this standard, HEU has an enrichment that is at least 93.5% 235 U, DU at 0.2% 235 U, and U nat

RGPu contains 24% 240 Pu and WGPu 6% 240 Pu.

at 0.7%.

The monitor shall identify the following radionuclides, or at least those stated by the manufacturer at the reference speed for that specific application, or measurement cycle time as stated by the manufacturer:

⎯ HEU, RGPu, and WGPu.

For transitory measurements, pass each source through the detection zone horizontally at the required test





23


ANSI N42.38-2006






The test for either transitory or stationary measurements shall consist of ten consecutive trials for each radionuclide in each configuration as required for that monitor’s application. The monitor’s alarm shall be reset between each trial, if appropriate. There shall be a 10 s delay between each trial with the source either positioned at a distance where it does not affect the background or is shielded during the delay.

The performance is acceptable when the monitor correctly identifies the radionuclide in eight out of ten

consecutive trials and the visual indication for SNM, as defined in step 5.11.2.1, is activated for each alarm.

6.8.3

Identification of shielded radionuclides

6.8.3.1

Requirements based on shielding related to shipping containers

The manufacturer shall provide a list of shielded radionuclides that the monitor can identify. For this standard, the source is surrounded by 3 cm of steel on all sides.

The list shall contain the following radionuclides, as a minimum:

⎯ 133 Ba, 137 Cs, and 60 Co

NOTE—3 cm steel is based on possible shipping container configurations and attenuation of gamma-ray emissions from each radionuclide.

6.8.3.2

Requirements based on medical treatments

The manufacturer shall provide a list of radionuclides that the monitor can identify when monitoring people with medical treatments. For this standard, the source is surrounded by 7.62 cm of polymethyl methacrylate

(PMMA). See Table 3 for additional information. The list shall contain the following radionuclides, as a

minimum:

⎯ 67 Ga, 99m Tc, 131 I, 201 Tl

6.8.3.3

Test method

The following test shall be performed to verify claims made based on the lists shown in sections 6.8.3.1 and

6.8.3.2. It is not necessary to validate claims for non-listed radionuclides.

NOTE— 133 Ba(i) and 60 Co(i) are used for the following test. Note that “i” describes those sources used for identification testing.

For transitory measurements, pass each source horizontally through the detection zone at the required test





24


ANSI N42.38-2006






The test for either transitory or stationary measurements shall consist of ten consecutive trials for each radionuclide in each configuration as required for that monitor’s application. The monitor’s alarm shall be reset between each trial, if appropriate. There shall be a 10 s delay between each trial with the source either positioned at a distance where it does not affect the background or is shielded during the delay.

The performance is acceptable when the monitor correctly identifies the radionuclide in eight out of ten consecutive trials.

6.8.4

Simultaneous radionuclide identification

6.8.4.1

Requirement a) b)

The monitor shall have the ability to identify more than one radionuclide simultaneously.

Simultaneous identification ability shall consist of radionuclides from separate categories (e.g.,

99m Tc + 137 Cs, 131 I + RGPu).

The monitor shall have the ability to identify a radionuclide of interest when combined with other radionuclides.

6.8.4.2

Test method

Testing shall be performed using combinations of radionuclides from 6.8.2.1. The activities shall be based

on the activities shown in Table 3. The following combinations shall be used for testing:

⎯ 40 K + 226 Ra + 232 Th + RGPu

⎯ 40 K + 226 Ra + 232 Th + DU

⎯

⎯

99m

Tc+ DU

131 I+ RGPu

For transitory measurements, pass each source combination horizontally through the detection zone at the

required test speed and at the application-specific distance (see Table 1). The transit heights shall be based

on the application and are the bottom, middle, and top of the detection zone and the mid-point between the middle and bottom, and middle and top planes. The test shall be performed using the radionuclides listed in

Table 3 in the unshielded configuration.


For stationary measurements, manually start a measurement cycle with each source combination positioned

in the horizontal center of the detection zone at the application-specific distance (see Table 1). The heights

shall be based on the application and are the bottom, middle, and top of the detection zone and the midpoint between the middle and bottom, and middle and top planes. As in the transitory measurements, the

test shall be performed using the radionuclides listed in Table 3 in the unshielded configuration.

The test for either transitory or stationary measurements shall consist of ten consecutive trials for each radionuclide in each configuration as required for that monitor’s application. The monitors’ alarm shall be

25


ANSI N42.38-2006

American National Standard Performance Criteria for Spectroscopy-Based Portal Monitors Used for Homeland Security reset between each trial, if appropriate. There shall be a 10 s delay between each trial with the source either positioned at a distance where it does not affect the background or is shielded during the delay.


6.8.5

Over-range characteristics for identification

6.8.5.1

Requirement

The manufacturer shall state the maximum gamma-ray exposure rate ( μ R/hr) for identification. The exposure rate shall be based on

137

Cs.

6.8.5.2

Test method

Position a 137 Cs source as needed to increase the ambient exposure rate to the maximum exposure rate for radionuclide identification as stated by the manufacturer [or at least by 0.1 mR/h (1 µSv/hr) at the face of the detection assembly if there is no manufacturer stated value available]. Restart the system with the 137 present and perform a radionuclide identification using 60

Co at the activity level indicated in Table 3.

Cs

For transitory measurements, pass the 60 Co source through the detection zone horizontally at the required

test speed and at the application-specific distance (see Table 1). The transit height shall be through the

middle of the detection zone.


For stationary measurements, manually start a measurement cycle with the 60 Co source positioned in the

horizontal center of the detection zone at the application-specific distance (see Table 1). The height shall be

the middle of the detection zone.

The test for either transitory or stationary measurements shall consist of ten consecutive trials. The monitor’s alarm shall be reset between each trial, if appropriate. There shall be a 10 s delay between each trial with the 60 Co source either positioned at a distance where it does not affect the background or is shielded during the delay. The 137 Cs source shall remain in position during the test to maintain the ambient background intensity.

6.8.6

Pile-up effects

6.8.6.1

Requirement

The monitor shall correctly identify radionuclides that are associated with people who have recently received radiation therapy treatments ( 131 I).

6.8.6.2

Test method

Testing shall be performed using a 30 mCi 131

I source placed in a PMMA shield (see 6.8.3.2).

For transitory measurements, pass the source horizontally through the detection zone at the required test

speed and at the application-specific distance (see Table 1). The transit height is the middle of the detection

zone.


26


ANSI N42.38-2006


For stationary measurements, manually start a measurement cycle with the source positioned in the

horizontal center of the detection zone at the application-specific distance (see Table 1). The test height is

the middle of the detection zone.

The test for either transitory or stationary measurements shall consist of ten consecutive trials for each radionuclide in each configuration as required for that monitor’s application. The monitor’s alarm shall be reset between each trial, if appropriate. There shall be a 10 s delay between each trial with the source either positioned at a distance where it doesn’t affect the background or shielded during the delay.


6.9

Determination of full-energy-peak efficiency

6.9.1

Requirement

The manufacturer shall state the full-energy-peak efficiency for

133 Ba (356 keV at 62.05%, T

1/2

= 10.5 years),

57 Co (122 keV at 85.51%, T

137 Cs (662 keV at 85.1%, T

= 5.27 years).

1/2

= 30 years), and

1/2

60

= 272 days),

Co (1173 and

1332 keV at 99.857% and 99.983%, respectively, T

1/2

NOTE—Data from Evaluated Nuclear Structure Data File (ENSDF) and Bureau National de Métrologie-Laboratoire

National Henri Becquerel/Commissariat á l’énergie atomique (BNM-LNHB/CEA).

6.9.2

Test method

Prior to performing the test, collect a 1 min background spectrum and record the total counts obtained. One at a time, position each source at the center of the detection zone and collect a spectrum until a minimum of

10 000 net counts are obtained. Determine the full-energy-peak efficiency, as seen in Equation (1) for each

source by:

η

a

= 100

A

N s

(1) where:

η a

N s is the full-energy-peak efficiency (%)

A counts in the full-energy peak, less background

is the total number of photons of the given energy emitted by the source during the counting time

Record the efficiency, the system-stated full-energy-peak value, and its associated channel number on the test data sheet. If the system uses multiple detectors, perform the test for each detector.

6.10

Determination of full width-half maximum (FWHM)

6.10.1

Requirement

The manufacturer shall state the FWHM as defined in the IEEE standard appropriate to the detector used for 137 Cs (662 keV at 85.1%).

27


ANSI N42.38-2006


6.10.2

Test method

Obtain a spectrum using the guidance found in step 6.9 and calculate the FWHM. Record the results in

percent on the data sheet for each detector if multiple detectors are used. The determined FWHM shall be within ±20% of the manufacturer-stated FWHM.

7.

Environmental performance requirements

7.1

Ambient temperature

7.1.1

Requirement

The monitor shall be able to operate over an ambient temperature range from − 30°C to +55°C.

It is permissible, but not recommended, to test the system by testing components only, such as detector(s) and any components designed for use in an uncontrolled environment. If cooling or heating systems are part of the detection system it is not possible to test components only.

This test should be carried out in an environmental chamber. Humidity levels should be low enough to prevent condensation (<65% RH) and the rate of change of temperature shall not exceed 10°C per hour.

7.1.2

Test method

For this test, the monitor’s response shall consist of collecting a series of gross gamma-ray and neutron readings using 57 Co and 60 Co, and 252

Cf (see Table 3 for source information). The response shall also

consist of a ten trial identification using 57 Co and identifications out of ten trials for each radionuclide.

60 Co. Record the identification results as x correct

The results at each temperature test point from each series of identifications shall be the same or better than the identification results obtained at the nominal temperature to be acceptable. For example, if the ten trial results at 22 °C and <65% RH are correct in six out of ten trials, the results at each test point shall be six or more correct. For the gross response channels, the results are acceptable if the mean readings obtained at each temperature test point are within ±15% of the mean readings obtained at the nominal temperature.

Prior to the test, obtain the monitor’s response at the nominal temperature and relative humidity (RH) of

22 °C and <65% RH respectively. The coefficient of variation (COV) for each mean reading shall be less than or equal to 12%. If the COV is >12%, the exposure rate should be increased to reduce the variation between each reading. The mean readings shall then be used to establish each acceptance range of ±15%. In addition, while at the nominal temperature, perform a ten trial radionuclide identification using 57 Co and

60 Co and record the results as x correct for ten trials for each radionuclide.

Following the nominal temperature stabilization period of 2 h, decrease the temperature at a rate not exceeding 10 ºC/hour to the low temperature test point. The monitor shall be observed during the temperature ramp and any functional changes shall be recorded. The temperature shall be maintained at the low-temperature test point for a minimum of 16 h. The monitor’s response shall be obtained at the beginning, middle, and end of the 16 h period.

Following the low-temperature exposure, increase the temperature at the 10 ºC/hour rate stopping at − 20, 0, and +40 o C for a period of 4 h at each test point. The monitor shall be observed during the temperature ramp and any functional changes shall be recorded. The monitor’s response shall be obtained during the last 30 min of each test temperature. Increase the temperature to the upper-temperature test point at a rate

28


ANSI N42.38-2006

American National Standard Performance Criteria for Spectroscopy-Based Portal Monitors Used for Homeland Security not exceeding 10 ºC/hour and maintain the temperature for a minimum of 16 h. The monitor’s response shall be obtained at the beginning, middle, and end of the 16 h period.

Following the upper temperature exposure, return the temperature to the nominal temperature and after a

2 h stabilization period, and obtain the monitor’s response.

7.2

Relative humidity

7.2.1

Requirement

The monitor shall be able to operate during and after exposure to relative humidity (RH) levels of up to

93% RH at an ambient temperature of +40°C.

There shall not be any observable effects from the exposure.

It is permissible, but not recommended, to test to test the system by testing components only, such as detector(s) and any components designed for use in an uncontrolled environment. If cooling or heating systems are part of the detection system, it is not possible to test components only.

7.2.2

Test method

For this test, the monitor’s response consists of collecting a series of gross gamma-ray and neutron readings using 57 Co and 60 Co, and 252

Cf (see Table 3 for source information). The response shall also consist of a ten

trial identification using 57 Co and 60 Co. Record the identification results as x correct identifications out of ten trials for each radionuclide.

The results at each humidity test point from each series of identifications shall be the same or better than the identification results obtained at the nominal humidity to be acceptable. For example, if the ten trial results at 22 °C and 65% RH are correct in six out of ten trials, the results at each test point shall be six or more correct. For the gross response channels, the results are acceptable if the mean readings obtained at each humidity test point are within ±15% of the mean readings obtained at the nominal humidity.

Prior to the test, the monitor’s response shall be obtained at the nominal temperature and relative humidity

(RH) of 22 °C and 65% RH, respectively. The coefficient of variation (COV) for each mean reading shall be less than or equal to 12%. If the COV is >12%, the exposure rate should be increased to reduce the variation between each reading. The mean readings shall then be used to establish each acceptance range of

±15%.

Following the nominal conditions stabilization period of 2 h, increase the humidity and temperature at a rate not exceeding 10% RH and 10 °C per hour respectively until attaining 93 ± 3% RH and 40°C. The humidity shall be maintained at this value for 16 h and the monitor’s gamma-ray and neutron readings noted every hour.

The humidity shall then be reduced to 65% RH while maintaining the temperature at 40°C. Obtain the monitor’s response after allowing the monitor to stabilize in those conditions for a minimum of 2 h.

Reduce the temperature to 22 °C at rate of 10 °C per hour to complete the test.

29


ANSI N42.38-2006


7.3

Moisture and dust protection

7.3.1

Requirement

The monitor, including components designed for use in an unprotected environment, shall meet the requirements stated for IP code 54 (see IEC 60529), protected from the ingress of dust and splashing water.

For IP54, the ingress of dust is not totally prevented, but dust shall not penetrate in a quantity to interfere with satisfactory operation of the instrument or to impair safety, and water splashed against the enclosure from any direction shall have no harmful effects.

7.3.2

Test method—dust

The test shall be made using a dust chamber (IEC 60529, category 2) where the powder circulation pump may be replaced by other means suitable to maintain the talcum powder (or Portland cement) in suspension in a closed test chamber. The amount of powder to be used should be 2 kg per cubic meter of the test chamber volume. The powder shall not have been used for more than 20 tests.

If the monitor uses multiple identical detector assemblies, it is only necessary to test one assembly.

The monitor shall be exposed to a 137 Cs source that is of sufficient intensity to minimize the effect of the statistical fl uctuations of the exposure rate readings. The monitor shall then be exposed to the dust environment for a period of 1 h. The monitor shall remain within ±15% of the pre-test response throughout the test and after the test.

Following exposure, an inspection shall be performed to determine the extent of dust ingress. The protection is satisfactory if, on inspection, powder has not accumulated in a quantity or location such that, as with any other kind of dust, it could interfere with the correct operation of the monitor or impair safety.

7.3.3

Test method—moisture

The test shall be made using a suitable nozzle (see IEC 60259, spray nozzle) with the water pressure adjusted to give a flow rate of 10 l/min ± 5%, which should be kept constant during the test. The water temperature should differ by not more than 5 ºK from the temperature of the monitor under test. The test duration is 1 min/m 2 of the calculated surface area of the monitor with a minimum duration of 15 min.

Prior to the test, the monitor shall be exposed to a 137 Cs source that is of sufficient intensity to minimize the effect of the statistical fl uctuations of the exposure rate readings. The monitor shall then be exposed to the water spray. The spray nozzle should be located approximately 2 m from the monitor. The monitor shall remain within ±15% of the pre-test response throughout the test and after the test.

The monitor shall be positioned as it would be during field use. The nozzle shall be positioned such that it is directly pointed at a vertical side of the monitor. During the exposure, the orientation shall be changed by

+60º and − 60º in two orthogonal planes along each side of the monitor. All sides shall be exposed to the water spray.

Following exposure, the monitor shall be visually inspected to ensure that moisture did not penetrate the enclosure.

30


ANSI N42.38-2006


8.

Electromagnetic performance requirements

8.1

Electrostatic discharge (ESD)

8.1.1

Requirement

The monitor shall function properly after exposure to electrostatic discharges at intensities of up to 6 kV.

8.1.2

Test method

In order to evaluate a monitor’s immunity to ESD, the contact discharge technique shall be used.

Discharge points shall be selected based on user accessibility.

There shall be ten discharges per discharge point with a 1 s recovery time between each discharge. It is recommended that tests first be performed at 2 kV, then if acceptable, 4 kV, followed by 6 kV.

The test is acceptable if no alarms or other spurious indications occur and there is no substantial change in response (reproducible deviations exceeding ±15% of the initial mean gamma-ray or neutron readings).

This test shall be performed under non-occupancy and occupancy operations.

8.2

Radio frequency (RF) susceptibility

8.2.1

Requirement

The monitor should not be affected by RF fields over the frequency range of 20 MHz to 2500 MHz at an intensity of 10 volts per meter (V/m).

8.2.2

Test method

NOTE—Due to the physical size of a portal monitor system, individual components can be gathered together for test purposes, although this is not recommended.

Place the monitor (as a whole system or collection of components) in a controlled RF environment and expose it to an RF field of 20 V/m over a frequency range of 20 MHz to 2500 MHz that is 80% amplitude modulated with a 1 kHz sine wave.

NOTE—Due to the physical size of a portal monitor system, it may be necessary to reposition the system within the RF field to ensure that each area is exposed at the proper intensity.

The test should be performed using an automated sweep at a frequency change rate not greater 1% of the fundamental (previous) frequency. Dwell time should be chosen based on the monitor’s response time, but should not be less than 3 s.

NOTE—20 V/m is selected so that the test can be performed in one orientation.

If susceptibilities are indicated by substantial changes in the indicated readings (deviations exceeding ±15% of the initial mean gamma-ray or neutron readings) or other operational changes such as alarm activation, the RF exposure shall be repeated over the range of susceptibility at 10 V/m in three orientations relative to the emission source.

31


ANSI N42.38-2006


The test is acceptable if no alarms, spurious indications, or reproducible changes in response occur that exceed ±15% of the initial indicated value.

8.3

Radiated emissions

8.3.1

Requirement

The emission limits when measured at 3 m shall be less than what is shown in Table 5.

Table 5 —Emission Frequency Range

MHz

Field strength

(microvolts/meter)

30–88 100

88–216 150

216 – 960 200

>960 500

8.3.2

Test method

NOTE—A non-shielded room is acceptable provided the ambient RF environment is well-known and controlled.

Place the monitor in an area with a low and controllable radio frequency environment. Position an antenna

3 m from the assembly. With the monitor off, collect a background spectrum using a scanning bandwidth of

50 kHz. Switch the monitor on and perform an RF scan for both non-occupancy and occupancy operations.

The monitor shall be positioned to ensure that the measurement is performed where the emissions are at the highest intensity.

Radio frequency emissions shall be below the values stated in 8.3.1.

8.4

Conducted disturbances induced by bursts and radio frequencies

8.4.1

Requirement

The monitor should not be affected by RF fields that can be conducted onto the monitor through an external conducting cable.

8.4.2

Test method

Place the 137 Cs gamma-ray and 252 Cf neutron test sources in a location that provide stable readings and expose the monitor to a conducted RF field over the frequency range of 150 kHz to 80 MHz at an intensity of 140 dB ( μ V) 80% amplitude modulated with a 1 kHz sine wave.

The test should be performed using an automated sweep at a frequency change rate not greater 1% of the fundamental (previous) frequency. Dwell time should be chosen based on the monitor’s response time, but should not be less than 3 s.

The test is acceptable if no alarms or other spurious indications occur, and there is no substantial change in response (reproducible deviations exceeding ±15% of the initial mean gamma-ray or neutron readings).

32


ANSI N42.38-2006



8.5

Magnetic fields

8.5.1

Requirement

The monitor should be unaffected by a 30 Amperes/meter (A/m) 60 Hz magnetic field.

NOTE—1 A/m is equivalent to a free space induction of 1.26 mTesla.

8.5.2

Test method

Place the 137 Cs and 252 Cf test sources in a location that provides a stable response and expose the monitor to a 30 A/m 60 Hz magnetic field. The exposure shall be done in at least two orientations (0° and 90°) relative to the field lines.

The test is acceptable if no alarms or other spurious indications occur and there is no substantial change in each channels’ reading (reproducible deviations exceeding ±15% of the initial mean gamma-ray or neutron readings).

8.6

Surges and oscillatory waves

8.6.1

Requirement

The monitor should not be affected by surges or oscillatory waves of up to 2 kV that are classified as ring waves or combination waves at 1.2/50 μ s and 8/20 μ s.

8.6.2

Test method

Apply ten pulses to the device with a minimum time between surges of 1 min. Each pulse should consist of a combination wave (1.2/50 μ s and 8/20 μ s) at an intensity of 2 kV.

Apply ring wave pulses of not more than 2 kV.

The test is acceptable if no alarms or other spurious indications occur and there is no substantial change in response (reproducible deviations exceeding ±15% of the initial mean gamma-ray or neutron readings).


33


ANSI N42.38-2006


9.

Mechanical performance requirements

9.1

Vibration

9.1.1

Requirement

The monitor shall function normally when exposed to vibrations associated with equipment installed in non-weather protected locations of up to 0.5 g shall not come loose). n

over a frequency range from 10 Hz to 150 Hz. The physical condition of the monitor should not be affected by exposure (e.g., solder joints shall hold; nuts and bolts

9.1.2

Test method

It is permissible to test the system by testing components that may be exposed to the vibratory environment, such as an individual detector(s), or an individual detector panel, and the controller.

Mounting mechanisms shall be used as much as practical to ensure that the test represents the usage environment as much as possible.

Prior to the test, a series of readings (at least 10) using 137 Cs and 252 Cf (gamma-ray and neutron, respectively) shall be obtained. The coefficient of variation (COV) for each mean reading shall be less than or equal to 12%. If the COV is >12%, the exposure rate should be increased to reduce the variation between each reading. The mean readings shall then be used to establish each acceptance range of ±15%.

Remove the sources and subject the detection assembly and any other component that may be operated in the same environment to harmonic loadings of 0.5 g n

over a frequency range from 10 Hz to 150 Hz while the system is active or occupied.

The test shall consist of ten 2 min logarithmic sweep cycles through the frequency range. The orientation used for testing shall be the same as that used when mounted in the field.

The test is acceptable if no alarms or other spurious indications occur and the mean readings determined from a series of readings from each channel following vibration are within ±15% of the pre-test gamma-ray and neutron mean readings.

After the test, inspect the monitor for mechanical damage and loose components. Note the results of the inspection on the data sheet.

9.2

Microphonics/impact

9.2.1

Requirement

The monitor shall be unaffected by microphonic conditions such as those that may occur from low-intensity sharp contacts at energies of up to 1.0 J. 1.0 J is equivalent to a mass of 1 kg moving at 1.4 m/s over a distance of 0.1 m.

34


ANSI N42.38-2006


9.2.2

Test method

Using an appropriate test device (e.g., spring hammer), expose the detector assembly to three 1.0 J impacts.

The impact test should be performed at three locations close to the electronics and at three other locations close to the detectors inside the monitor assembly.

The test is acceptable if no alarms or other spurious indications occur and there is no substantial change in response (reproducible deviations exceeding ±15% of the initial mean gamma-ray or neutron responses).

The test shall be repeated for non-occupancy and occupancy operations.

10. Documentation

10.1

Type test report

The manufacturer shall make available, at the request of the purchaser, the report on the type tests performed to the requirements of this standard.

10.2

Report

The manufacturer shall provide the following information, as a minimum:

⎯ Contact information for the manufacturer including name, address, telephone number, fax number, e-mail address, etc.

⎯ Type of portal monitor, detector, and types of radiation the monitor is designed to measure

⎯ Mounting distance between detection assemblies, as appropriate

⎯ Power supply requirements

⎯ Results of tests performed to this standard

⎯ Recommended operational parameters such as: detector response, false alarm probability, alarm thresholds, operating parameters, and libraries

⎯ Complete description of the evaluated monitor

⎯ Enclosure specification classification

⎯ Inclusion of any hazardous material that may require additional regulation (such as radionuclide check source)

⎯ List of radionuclides that are identified by the monitor

⎯ Over-range exposure rate values for gross counting and identification

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ANSI N42.38-2006


10.3 Operation and maintenance manual

The manufacturer shall supply an operation and maintenance manual containing the following information to the user:

⎯ Operating instructions and restrictions

⎯ Module connection schematic

⎯ Electrical connection schematic

⎯ Spare parts list

⎯ Troubleshooting guide

⎯ Description and protocol for communication methods of transmitting and receiving data

36


ANSI N42.38-2006


Annex A

(informative)

Bibliography

A.1

General

[B1] IEC 60068-2, Basic Environmental Testing Procedures—Part 2: Tests.

12

[B2] IEEE Std C62.41™-1991, IEEE Recommended Practice on Surge Voltages in Low-Voltage AC

Power Circuits.

13, 14

[B3] UL 913-2002, Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III,

Division 1, Hazardous (Classified) Locations.

15

A.2

Detectors

[B4] ANSI N42.12-1994, American National Standard for Calibration and Usage of Thallium-Activated

Sodium Iodide Detector Systems for Assay of Radionuclides.

16

[B5] ANSI N42.13-2004, American National Standard Calibration and Usage of "Dose Calibrator"

Ionization Chambers for the Assay of Radionuclides.

[B6] ANSI N42.14-1999, American National Standard for Germanium Spectrometer for the Measurement of Gamma-Ray Emission Rates of Radionuclide Sources.

[B7] ANSI N42.31-2003, American National Standard for Measurement Procedures for Resolution and

Efficiency of Wide-Bandgap Semiconductor Detectors of Ionizing Radiation.

[B8] IEEE Std 300™-1998, IEEE Standard Test Procedures for Semiconductor Charged-Particle

Detectors.

[B9] IEEE Std 309™-1999/ANSI N42.3-1999 (Reaff 2006), IEEE Standard Test Procedures and Bases for Geiger-Mueller Counters.

[B10] IEEE Std 325™-1996 (Reaff 2002), IEEE Standard Test Procedures for Germanium Gamma-Ray

Detectors.

12

IEC publications are available from the Sales Department of the International Electrotechnical Commission, Case Postale 131, 3, rue de Varembé, CH-1211, Genève 20, Switzerland/Suisse (http://www.iec.ch/). IEC publications are also available in the United

States from the Sales Department, American National Standards Institute, 11 West 42nd Street, 13th Floor, New York, NY 10036,

USA.

13

IEEE publications are available from the Institute of Electrical and Electronics Engineers, 445 Hoes Lane, Piscataway, NJ 08855-

1331, USA (http://standards.ieee.org/).

14

The IEEE standards referred to in this annex are trademarks belonging to the Institute of Electrical and Electronics Engineers, Inc.

15

UL standards are available from Global Engineering Documents, 15 Inverness Way East, Englewood, Colorado 80112, USA

(http://global.ihs.com/).

16

The ANSI N42 publications included in this annex are available from the Institute of Electrical and Electronics Engineers, 445

Hoes Lane, Piscataway, NJ 08855-1331, USA (http://standards.ieee.org/).

37


ANSI N42.38-2006


A.3

Detection and identification instruments

[B11] ANSI 42.32-2006, American National Standard Performance Criteria for Alarming Personal

Radiation Detectors for Homeland Security.

[B12] ANSI 42.33-2006, American National Standard for Portable Radiation Detection Instrumentation for

Homeland Security.

[B13] ANSI 42.34-2006, American National Standard Performance Criteria for Hand-held Instruments for the Detection and Identification of Radionuclides.

[B14] ISO 22188:2004, Monitoring for Inadvertent Movement and Illicit Trafficking of Radioactive

Material.

17

A.4

Radiological protection instruments

[B15] ANSI N42.17A-2004, American National Standard Performance Specifications for Health Physics

Instrumentation—Portable Instrumentation for Use in Normal Environmental Conditions.

[B16] ANSI N42.17B-1989 (Reaff 2005), American National Standard Performance Specifications for

Health Physics Instrumentation—Occupational Airborne Radioactivity Monitoring Instrumentation.

[B17] ANSI N42.17C-1989 (Reaff 2005), American National Standard Performance Specifications for

Health Physics Instrumentation—Portable Instrumentation for Use in Extreme Environmental Conditions.

[B18] ANSI N42.20-2003, American National Standard Performance Criteria for Active Personnel

Radiation Monitors.

[B19] ANSI N323A-1997, American National Standard Radiation Protection Instrumentation Test and

Calibration—Portable Survey Instruments.

[B20] IEC 60395:1972, Portable X or Gamma Radiation Exposure Rate Meters and Monitors for Use in

Radiological Protection.

A.5

EMC

[B21] IEC 61000-4-3: 2006, Electromagnetic Compatibility (EMC)—Part 4-3: Testing and Measurement

Techniques—Radiated, Radio-Frequency, Electromagnetic Field Immunity Test.

[B22] IEC 61000-4-6: 2006, Electromagnetic Compatibility (EMC)—Part 4-6: Testing and Measurement

Techniques—Immunity to Conducted Disturbances, Induced by Radio-Frequency Fields.

[B23] IEC 61000-6-2:2005, Electromagnetic Compatibility (EMC)—Part 6-2: Generic Standards—

Immunity for Industrial Environments.

[B24] FCC Rules, Code of Federal Regulations, Title 47, Part 15,Radio Frequency Devices, 2002.

18

17

ISO publications are available from the ISO Central Secretariat, Case Postale 56, 1 rue de Varembé, CH-1211, Genève 20,

Switzer-land/Suisse (http://www.iso.ch/). ISO publications are also available in the United States from the Sales Department,

American National Standards Institute, 25 West 43rd Street, 4th Floor, New York, NY 10036, USA (http://www.ansi.org/).

18

CFR publications are available from the Superintendent of Documents, U.S. Government Printing Office, P.O. Box 37082,

Washington, DC 20013-7082, USA (http://www.access.gpo.gov/).

38


ANSI N42.38-2006


A.6

Units, quantities, and calibrations

[B25] ICRU Report 33-1980, Radiation quantities and units.

19

[B26] ISO 4037-1:1996, X and Gamma Reference Radiation for Calibrating Dosemeters and Doserate

Meters and for Determining their Response as a Function of Photon Energy—Part 1: Radiation

Characteristics and Production Methods.

[B27] ISO 4037-2:1997, X and Gamma Reference Radiation for Calibrating Dosemeters and Doserate

Meters and for Determining their Response as a Function of Photon Energy—Part 2: Dosimetry for

Radiation Protection over the Energy Ranges from 8 keV to 1.3 MeV and 4 MeV to 9 MeV.

[B28] ISO 8529-1:2001, Reference Neutron Radiations—Part 1: Characteristics and Methods of

Production.

[B29] ISO 8529-2:2000, Reference Neutron Radiations—Part 2: Calibration Fundamentals Related to the

Basic Quantities Characterizing the Radiation Field.

[B30] NIST SP 250-98, NIST Calibration Services Users Guide.

20

A.7

Security monitors

[B31] ASTM C993-97 (2003), Standard Guide for In-Plant Performance Evaluation of Automatic

Pedestrian SNM Monitors.

21

[B32] ASTM C1112-99 (2005), Standard Guide for Application of Radiation Monitors to Control and

Physical Security of Special Nuclear Material.

[B33] ASTM C1169-97 (2003), Standard Guide for Laboratory Evaluation of Automatic Pedestrian SNM

Monitor Performance.

[B34] ASTM C1189-02 Standard Guide to Procedures for Calibrating Automatic Pedestrian SNM

Monitors.

[B35] ASTM C1237-99 (2005), Standard Guide for In-Plant Performance Evaluation of Hand-Held SNM

Monitors.

19

ICRU publications are available from the International Commission on Radiation Units and Measurements, Inc, 7910 Woodmont

Ave, Suite 400, Bethesda, MD 20814-3095, USA (http://www.icru.org).

20

Information on NIST Special Publications may be obtained from the National Institute of Standards and Technology at http://www.nist.gov/.

21

ASTM publications are available from the American Society for Testing and Materials, 100 Barr Harbor Drive, West

Conshohocken, PA 19428-2959, USA (http://www.astm.org/).

39


ANSI N42.38-2006


Annex B

(informative)

Diagram of mounting dimensions for radionuclide identifying portal monitors

3

Detection Zone Mid-point between middle and top

1

H

Detection Assembly

W

Mid-point between middle and bottom

2

Figure B.1—Example of a two-sided system

W = Width of the detection zone

H = Height of the detection zone

The arrows indicate the movement of radiation sources through the detection zone.

Positions are indicated as follows:

2 = bottom

1 = center (reference) of detection zone

3 = top

40
