IEC 61275:2013

IEC 61275 ®
Edition 2.0 2013-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Radiation protection instrumentation – Measurement of discrete radionuclides in
the environment – In situ photon spectrometry system using a germanium
detector
Instrumentation pour la radioprotection – Mesure de radionucléides discrets
présents dans l'environnement – Système de spectrométrie gamma in situ
utilisant un détecteur au germanium
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IEC 61275 ®
Edition 2.0 2013-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Radiation protection instrumentation – Measurement of discrete radionuclides

in the environment – In situ photon spectrometry system using a germanium

detector
Instrumentation pour la radioprotection – Mesure de radionucléides discrets

présents dans l'environnement – Système de spectrométrie gamma in situ

utilisant un détecteur au germanium

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 13.280 ISBN 978-2-83220-824-3

– 2 – 61275 © IEC:2013
CONTENTS
FOREWORD . 5
1 Scope and object . 7
2 Normative references. 7
3 Terms and definitions . 8
3.1 Definitions . 8
3.2 Test nomenclature . 10
4 General requirements . 10
4.1 Basic components . 10
4.2 Examples of detector types . 11
5 Classification of the performance characteristics . 11
6 General characteristics . 11
6.1 Indication . 11
6.2 Effective range of measurement of an assembly . 12
6.3 Detector cooling . 12
6.4 Detector type . 12
6.5 Detector housing . 12
6.6 Detector window . 12
6.7 Ease of decontamination. 12
6.8 Safety considerations . 12
6.9 Calibration . 12
7 General test procedures. 12
7.1 Nature of tests . 12
7.2 Reference conditions and standard test conditions . 13
7.3 Position of assembly for purposes of tests . 13
7.4 Statistical fluctuations . 13
7.5 Low-level measurements . 13
7.6 Reference radiation . 13
8 Radiation tests . 13
8.1 Variation of response with photon radiation energy . 13
8.1.1 Requirements . 13
8.1.2 Test method . 14
8.2 Variation of response with angle of incidence . 14
8.2.1 Requirements . 14
8.2.2 Test methods . 14
8.3 Resolution . 14
8.3.1 Requirements . 14
8.3.2 Test methods . 14
8.4 Background contamination from the instrument assembly . 14
8.4.1 Requirements . 14
8.4.2 Test method . 15
9 Assembly characteristics. 15
9.1 Statistical fluctuations . 15
9.1.1 Requirements . 15
9.1.2 Test method . 15
9.2 Warm-up time . 15
9.2.1 Requirements . 15

61275 © IEC:2013 – 3 –
9.2.2 Test method . 15
9.3 Power supplies – Battery operation . 15
9.3.1 Requirements – batteries . 15
9.3.2 Test method . 15
9.4 Power supplies – Mains operation . 16
9.4.1 Requirements . 16
9.4.2 Test method . 16
10 Mechanical characteristics . 16
10.1 Vibration and shock damage during transport and shipping . 16
10.1.1 Requirements . 16
10.1.2 Tests for vibration damage . 16
10.1.3 Tests for vibration resistance . 17
10.1.4 Tests for mechanical shock . 17
10.1.5 Tests for mechanical resistance . 17
11 Environmental requirements and tests . 18
11.1 Requirements and tests at temperature extremes . 18
11.1.1 Requirements . 18
11.1.2 Test method . 18
11.2 Influence of relative humidity (RH) . 19
11.2.1 Requirements . 19
11.2.2 Test method . 19
11.3 Wind resistance requirements and tests . 19
11.3.1 Requirements . 19
11.3.2 Test method . 19
11.4 Temperature cycling of detector . 19
11.4.1 Requirements . 19
11.4.2 Test method . 19
11.5 Sealing requirements . 19
11.6 External electromagnetic fields . 20
11.6.1 General . 20
11.6.2 Requirements . 20
11.6.3 Test method . 20
11.7 External magnetic fields . 20
11.7.1 Requirements . 20
11.7.2 Test method . 20
11.8 Storage and transport . 20
12 Calibration recommendations . 20
13 Documentation . 20
13.1 Certificate . 20
13.2 Operation and maintenance manuals . 21
Annex A (informative) Calibration . 26
Annex B (informative) Estimation of detector response from detector size, shape and
relative efficiency . 27
Annex C (informative) Data interpretation and use . 28
Annex D (informative) Expected total-absorption-peak count rates per unit deposition
for selected freshly deposited radionuclides . 31
Annex E (informative) Relative intrinsic uncertainty . 32
Bibliography . 33

– 4 – 61275 © IEC:2013
Figure 1 – Angular distribution of incident fluence . 25

Table 1 – Reference and standard test conditions. 22
Table 2 – Tests performed with variation of influence quantities . 23
Table 3 – Mechanical performance under test conditions . 24
Table 4 – Tests for vibrating survival capability at various fixed frequencies . 24
Table 5 – Tests for vibration resistance at smoothly varying frequencies . 25
Table C.1 – Primary photon fluence in air at a height of 1 m above the ground per unit
source photon per unit area of exponentially distributed sources in the ground . 29
–2
Table D.1 – Total absorption peak count rate per minute per kBq· m . 31

61275 © IEC:2013 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RADIATION PROTECTION INSTRUMENTATION – MEASUREMENT OF
DISCRETE RADIONUCLIDES IN THE ENVIRONMENT – IN SITU PHOTON
SPECTROMETRY SYSTEM USING A GERMANIUM DETECTOR

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
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Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61275 has been prepared by subcommittee 45B: Radiation
protection instrumentation, of IEC technical committee 45: Nuclear instrumentation.
This second edition cancels and replaces the first edition issued in 1997. It constitutes a
technical revision.
The main technical changes with regard to the previous edition are as follows:
– update the terminology to encompass the latest technologies,
– revise test methods to account for methodological developments and performance criteria
with the latest HPGe detector technologies and digital electronics.

– 6 – 61275 © IEC:2013
The text of this standard is based on the following documents:
FDIS Report on voting
45B/762/FDIS 45B/769/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
61275 © IEC:2013 – 7 –
RADIATION PROTECTION INSTRUMENTATION – MEASUREMENT OF
DISCRETE RADIONUCLIDES IN THE ENVIRONMENT – IN SITU PHOTON
SPECTROMETRY SYSTEM USING A GERMANIUM DETECTOR

1 Scope and object
This International Standard is applicable to a portable or transportable photon spectrometry
assembly using a high purity germanium (HPGe) detector to survey, in situ, generally at 1 m
above ground level, areas in the environment for discrete radionuclides. Such equipment is
used to make rapid assessments of activity levels and corresponding free air exposure rates
from photon emitting radionuclides. Such measurements may be used to develop guidance for
subsequent follow-up action, for example including radiological assessments, sampling and
monitoring programmes. (This standard does not apply to mobile measurement systems that
are covered by a separate standard. See IEC 62438.)
This standard specifies for such an assembly the general characteristics and test methods for
evaluating radiation, electrical, mechanical, safety and environmental characteristics specific to
the applications described above. Advice is also provided in annexes as to the calibration,
appropriate use and interpretation of the system for in situ measurements.
An in situ spectrometry system is a combination of instruments or assemblies designed to
measure, in situ, the fluence of gamma-rays incident on the detector, in order to rapidly survey
areas for discrete radionuclides present in the soil or air, either natural or manmade.
The purpose of this standard is to specify the performance characteristics of assemblies
intended for the determination of surface soil activity.
Accordingly, this standard
a) specifies the functions and performance characteristics of measuring assemblies; and
b) specifies the methods of testing compliance against the requirements of this standard.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
IEC 60068 (all parts), Environmental testing
IEC 61010-1, Safety requirements for electrical equipment for measurement, control and
laboratory use – Part 1: General requirements
IEC 61187:1993, Electrical and electronic measuring equipment – Documentation
IEC 62438:2010, Radiation protection instrumentation – Mobile instrumentation for the
measurement of photon and neutron radiation in the environment
ISO 4037 (all parts), X and gamma reference radiation for calibrating dosimeters and dose
ratemeters and for determining their response as a function of photon energy

– 8 – 61275 © IEC:2013
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE The general terminology concerning detection and measurement of ionizing radiation, nuclear
instrumentation and germanium detectors is given in IEC 60050-393, IEC 60050-394 and IEC 60973.
3.1 Definitions
3.1.1
angular response
the variation in response to a radionuclie of interest when it is moved in a fixed radius from the
assembly through angle theta from the normal (usually θ = 0°; see Figure 1)
Note 1 to entry: For cylindrical detectors it is only necessary to do this in a single plane.
3.1.2
coefficient of variation
the ratio V of the standard deviation s to the arithmetic mean x of a set of n measurements
of x , given by the following formula:
i
n
(x − x)
i
∑
s 1 1
V= =
x x n−1
[SOURCE: IEC 60050-394:2007, 394-40-14]
3.1.3
collimation
shielding used to systematically reduce the angular response and thus field of view of a
detector
3.1.4
detection threshold
lower detection limit
value of the indication of the measurement for which the relative random uncertainty equals
± 100 % at the probability level of 95 %
[SOURCE: IEC 60050-394:2007, 394-40-20]
3.1.5
effective range of measurement
range of values of the quantity to be measured over which the performance of an assembly
meets the requirements of this standard
3.1.6
energy calibration function
the function required to convert channel number to gamma-ray energy (keV)
3.1.7
energy resolution
the range in keV over which the response is greater that 50 % (Full Width at Half maximum –
FWHM) at a defined energy peak

61275 © IEC:2013 – 9 –
3.1.8
field of view
the area and volume of soil “viewed” by detector (effective sample size), usually defined as the
radial distance from which 90 % of the total incident gamma-ray fluence is derived
3.1.9
internal background
the count rate (counts per unit time) due to gamma-rays emitted from radionuclides intrinsic to
the detector assembly
3.1.10
N-type detector
a HPGe detector with the ion implanted surface or rectifying surface being the P+ surface that
is usually the outer surface of a detector crystal
3.1.11
P-type detector
a HPGe detector with the ion implanted surface or rectifying surface being the N+ surface that
is usually the outer surface of a detector crystal
3.1.12
portable system
a system that can be carried by one or two persons and with which field measurements can be
made while stationary or being carried. The system is completely battery-operated.
3.1.13
relative efficiency
The ratio, expressed in percentage, of the count rate in the 1 333 keV total absorption peak of
Co to the corresponding one obtained with a 76 mm × 76 mm NaI(Tl) scintillator for normal
incidence and at 25 cm from the source
3.1.14
relative uncertainty of an indication
the relative uncertainty, I, of the indication of an assembly is given, as a percentage, by the
relationship:
( − )
Hi H t
I = × 100 %
H t
where
H is the indicated value and H the conventionally true value.
i t
3.1.15
reference point of an assembly
a physical mark or marks on the assembly to be used in order to position it at a point where the
conventionally true value of the quantity to be measured is known. Generally, this point is taken
to be the location of the face of the germanium detector but will be dependent on the exact
construction of the detector assembly.
3.1.16
reference soil
an area of soil of extent greater than 10 m diameter for which the activity of particular radio-
nuclides has been well characterized as to concentration (Bq/kg) and distribution with depth

– 10 – 61275 © IEC:2013
3.1.17
response
the response, R, of an assembly is the ratio of the indicated value H of the incident fluence at
i
a given photon energy as inferred from the full energy peak area to the conventionally true
value H of the incident fluence. This may also be inferred to mean efficiency.
t
3.1.18
transportable system
a system that may be mounted in a vehicle, and is connected to the detector via a long signal
cable. The system generally uses an external power source and cannot be easily carried by a
single person.
3.2 Test nomenclature
3.2.1
qualification test
test performed in order to verify that the requirements of a specification are fulfilled.
Qualification tests are divided into type tests and routine tests.
3.2.2
type test
conformity test made on one or more items representative of the production
[SOURCE: IEC 60050-394:2007, 394-40-02]
3.2.3
routine test
conformity test made on each individual item during or after manufacture
[SOURCE: IEC 60050-394:2007, 394-40-03]
3.2.4
acceptance test
contractual test to prove to the customer that the device fulfills certain specifications
[SOURCE: IEC 60050-394:2007, 394-40-05]
4 General requirements
4.1 Basic components
A complete in situ photon spectrometry system consists of a number of individual subsystems
or instruments. The individual components are generally not unique in that the same
components may all be routinely used in other field and laboratory gamma-ray counting
systems. Their use in situ, as part of a special integrated portable or transportable system,
requires stringent environmental and mechanical qualifications as well as special electrical,
mechanical, and safety considerations not generally required for routine laboratory use. All
individual components including preamplifier, spectroscopy amplifier, power supply, data
acquisition and storage system, shall satisfy all applicable IEC standards governing their
normal manufacture and usage as well as the particular requirements of this standard. Their
use as an in situ system also requires special calibrations and careful interpretation of results.
Usually the assembly comprises the following components:
a) a gamma-ray detector, HPGe N-type or P-type detector (the detector includes an integral
cryostat and internally cooled charge-sensitive preamplifier);
b) a spectroscopy amplifier and high-voltage (HV) power electronics;

61275 © IEC:2013 – 11 –
c) data processing equipment that includes data acquisition capability, data recording
capability and visual display; it may be based on a multi-channel analyzer (MCA) with a
minimum of 4 096 channels, personal computer with built-in MCA capability or other
comparable devices;
d) a system power supply (see 9.4);
e) all necessary connecting cables;
f) a tripod or other type of support to mount the detector at a fixed height above the ground in
the field during acquisition of a gamma-ray spectrum;
g) a detector cooling system, which needs to be either a liquid nitrogen storage system
(cryostat and dewar) or an electromechanical cooler for maintaining the Ge crystal at
correct operating temperature;
h) a lightweight rugged, stable platform for mounting the detector at a fixed height above
ground shall be provided. The height and orientation of the mount should be repeatable.
The manufacturer shall state the effect of the mount position relative to the field of view and
the mass of material in the mount.
4.2 Examples of detector types
In a rapid survey of limited areas for discrete radionuclides, a portable system consisting of a
hand-held HPGe detector-cooler assembly and a portable data processing assembly (generally
a stand-alone or PC-based MCA with built-in detector bias HV and spectroscopy amplifier) is
recommended. For applications where portability is not essential, a transportable system can
be used. Transportable systems might, for example, consist of separate MCA, electronics and
power supply modules mounted inside a vehicle connected by an umbilical cable to a HPGe
detector in the field. For some applications, the detector may even be mounted on the vehicle
(refer to IEC 62438). Where survey work requires the detection of low energy gamma-ray,
below 100 keV and down to 3 keV, an N-type detector or specially adapted P-type detector with
a suitable beryllium or carbon fibre window may be more suitable than a standard P-type
detector encased in aluminum.
5 Classification of the performance characteristics
The limits of variation in the indication of an assembly are specified for each performance
characteristic in Tables 1 to 5 and in the appropriate subclauses. For some applications it may
not be deemed essential for an assembly to meet all the requirements set out below. In such
cases, the requirements to be applied to the assemblies may be specified by agreement
between the manufacturer and the purchaser, but the determination of the characteristics of
the assemblies shall conform to the methods given in the present standard.
If the mass, overall dimensions and construction of the instrument does not permit the testing
of the complete system as a whole by means of the existing test equipment, each component
may be tested separately in conformity with the present standard followed by a complete check
of the entire system under normal operating conditions. The procedure used for the test shall
be specified.
6 General characteristics
6.1 Indication
The indications of the assembly shall be in units of counts per channel and total counts in
selected total absorption peaks per unit time. The full spectrum, typically from 20 keV to
2 700 keV, should be accessible and energy calibrated to enable easy identification of
radionuclides. The indications of the assembly shall also be in units of activity per unit area or
–2 –1
mass for a given nuclide, for example Bq⋅m or Bq⋅kg for selected or defined depth
profile(s), as agreed upon between the purchaser and the manufacturer.

– 12 – 61275 © IEC:2013
6.2 Effective range of measurement of an assembly
When the test methods do not extend over the entire effective range of measurement and any
of the observed variations are near the permitted limit, further tests to demonstrate compliance
with the requirement in question over the whole effective range of measurement may be
necessary. Such further tests shall be the subject of agreement between the manufacturer and
the purchaser. For these systems the effective range of measurement is determined primarily
by the characteristics of the analog to digital conversion (dead time) and pile-up of pulses in
the amplifier and shall be specified by the manufacturer.
6.3 Detector cooling
The detectors should be maintained at a temperature between 80 K and 100 K and should be
capable of at least 8 h of continuously uninterrupted use. The manufacturers should specify the
cool down time.
6.4 Detector type
For maximizing low energy (E) detection (e.g., from Am 60 keV photons), an N-type or
special modified P-type germanium detector should be preferred over a P-type detector.
6.5 Detector housing
The housing shall be designed to minimize the attenuation of gamma-ray and the intrinsic
background. If found necessary, to minimize further the attenuation of low energy incident
gamma-rays, an entrance window, typically beryllium or carbon of thickness less than
–2
0,3 mg⋅cm , shall be used. The maximum thickness of the entrance window shall be such that
the attenuation of 1 333 keV gamma-rays incident axially (θ = 0) shall be less than 2 %.
6.6 Detector window
The detector window should be designed to minimize the possibility of damage or breakage. If
Be is used, instructions shall be provided for the safe handling of Be.
6.7 Ease of decontamination
The assembly shall be designed and constructed in such a manner as to facilitate
decontamination.
6.8 Safety considerations
The instruments shall comply with the safety requirements of IEC 61010-1.
6.9 Calibration
The requirements to calibration should be specified by agreement between the manufacturer
and the purchaser, but calibration recommendations is represented in Annex A.
7 General test procedures
7.1 Nature of tests
Unless otherwise specified in the individual clauses, all the tests enumerated in this standard
shall be considered type tests (see 3.3.1). Certain tests may be considered acceptance tests
by agreement between the manufacturer and the purchaser (see 3.3.1).

61275 © IEC:2013 – 13 –
7.2 Reference conditions and standard test conditions
Reference conditions are given in the second column of Table 1. Except where otherwise
specified, the tests in this standard shall be carried out under the standard test conditions
given in the third column of Table 1.
For those tests intended to determine the effects of variations in the influence quantities given
in Table 1, all other influence quantities shall be maintained within the limits for standard test
conditions given in Table 1, unless otherwise specified in the test procedure concerned.
7.3 Position of assembly for purposes of tests
For all tests involving the use of radiation, the reference point of the assembly (see 3.16) shall
be placed at the point where the conventionally true value of the quantity to be measured is
known, and in the orientation of the assembly indicated by the manufacturer.
7.4 Statistical fluctuations
For any test involving the use of radiation, if the magnitude of the statistical fluctuations of the
indication arising from the random nature of radiation alone is a significant fraction of the
variation of the indication permitted in the test, then sufficient readings shall be taken to ensure
that the mean value of such readings may be estimated with sufficient accuracy to demonstrate
compliance with the test in question.
The interval between such readings shall be sufficient to ensure that the readings are
statistically independent.
7.5 Low-level measurements
For the measurement of low levels of radioactive materials, it is necessary to take into account
of the contribution of background radiation from the instrument assembly to the indication at
the point of test (Annex E).
7.6 Reference radiation
Unless otherwise specified in the individual methods of test, all tests involving the use of
60 137
gamma-ray radiation shall be carried out with the nuclide Co or Cs (see Table 1). The
nature, construction and conditions of use of the radiation sources shall be in accordance with
ISO 4037.
8 Radiation tests
8.1 Variation of response with photon radiation energy
8.1.1 Requirements
The indication of the assembly when exposed to photon radiation point sources in the
calibration direction and of energy between 60 keV and 2 500 keV shall not differ from the
conventionally true value of the fluence of photons from such sources by more than the
following limits:
60 keV to 300 keV: ± 10 %
300 keV to 2 500 keV: ± 5 %
– 14 – 61275 © IEC:2013
8.1.2 Test method
The assembly shall be exposed to photon sources as specified in ISO 4037, having energies
spanning this range.
8.2 Variation of response with angle of incidence
8.2.1 Requirements
For the purposes of a calibration based on theoretical solutions (Annex A), the angular
response of the detector should be characterized. The response will vary as the angle of
incidence of the radiation changes relative to the reference orientation (Figure 1a).
Measurements shall be made at a distance of at least 1 m from the reference point and at least
nine azimuthal angles (θ) between 0° and 90° and three axial (Ψ) positions between 0° and
180°. A type test may be sufficient for detectors of similar size and shape and identical
housing.
8.2.2 Test methods
The assembly shall be exposed to a suite of radiation energies over the energy range of
interest, for example 40 keV to 2 500 keV. At each radiation energy the detector shall be
placed along a reference direction specified by the manufacturer for calibration purposes
(generally θ = 0°, Ψ = 0°; see Figure 1a). The reading in this position shall be noted. The
detector shall then be moved relative to the source through angles from θ = 0° to θ = 90°, in
steps of 10° keeping Ψ being kept constant, and the readings noted. The range for θ may be
reduced for collimated detectors.
Similar observations shall then be taken at Ψ = 120° and Ψ = 240° from the first arc (Ψ = 0°).
The variation of the reading of the assembly to radiation incident at any angle from Ψ, as θ is
varied from 0° to 90°, shall be stated by the manufacturer, and shall be used in calibrating the
response of the detector.
8.3 Resolution
8.3.1 Requirements
The spectral resolution requirements shall be agreed upon between the customer and
manufacturer. Capabilities will vary with crystal size but may be typically ≤ 1,9 keV (FWHM) at
1 333 keV for a HPGe detector of 30 % relative efficiency.
8.3.2 Test methods
The resolution shall be measured by the manufacturer for each detector with a high grade
laboratory gamma-ray spectrometry system using a Co point source placed at a distance
from the detector face such that the system dead time is less than 2 %, and by counting for
sufficient time to acquire 10 000 events in the photo peak. The user shall verify the resolution
before use, using the same method.
8.4 Background contamination from the instrument assembly
8.4.1 Requirements
The background radiation from the metal housing (including radiation entrance window),
molecular sieve or any other material in the vicinity of the detector shall have an equivalent
–1 40 232 238
effect no greater than the signal from 2,0 Bq⋅kg of natural K, Th or U uniformly
distributed in soil since some natural background peaks may overlap fission product peaks.

61275 © IEC:2013 – 15 –
8.4.2 Test method
Type tests for randomly selected assemblies shall be carried out by accumulating a spectrum
for a long enough time interval to verify that the requirement is met within plus/minus two
standard deviations at an energy calibration of 1 keV/channel and in a low background shielded
room or other facility. Alternatively, individual detector housing components may be analyzed
for natural activity by a reputable standards laboratory.
9 Assembly characteristics
9.1 Statistical fluctuations
9.1.1 Requirements
The coefficient of variation of the indication due to statistical fluctuations shall be less than
5 %.
9.1.2 Test method
Expose the assembly to a source of radiation
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