IEC 62438:2010

IEC 62438 ®
Edition 1.0 2010-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Radiation protection instrumentation – Mobile instrumentation for the
measurement of photon and neutron radiation in the environment

Instrumentation pour la radioprotection – Instrumentation mobile pour la
mesure des rayonnements gamma et neutroniques dans l'environnement

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IEC 62438 ®
Edition 1.0 2010-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Radiation protection instrumentation – Mobile instrumentation for the
measurement of photon and neutron radiation in the environment

Instrumentation pour la radioprotection – Instrumentation mobile pour la
mesure des rayonnements gamma et neutroniques dans l'environnement

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
W
CODE PRIX
ICS 13.280 ISBN 978-2-88910-703-2
– 2 – 62438 © IEC:2010
CONTENTS
FOREWORD.6
1 Scope and object.8
2 Normative references .8
3 Terms, definitions and nomenclature .9
3.1 Definitions .9
3.1.1 mobile detection system .9
3.1.2 energy resolution.9
3.1.3 background (intrinsic, platform and cosmic) .9
3.1.4 positional reference .9
3.1.5 area of investigation .9
3.1.6 sampling interval .9
3.1.7 reference soil or surface .10
3.1.8 platform .10
3.2 Test nomenclature.10
3.2.1 qualification tests .10
3.2.2 acceptance test .10
4 General system configuration .10
5 General requirements .11
5.1 Power supply.11
5.2 Battery power supply.12
5.3 Cabling and connections .12
5.4 Shock (operating) .12
5.5 Vibration (operating).12
5.6 Vibration (non-operating).12
5.7 Water resistance .12
5.8 Spectrometric systems .12
6 Classification of the performance characteristics .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 Reference radiation .13
8 General performance specification and testing requirement.13
8.1 Power supply.13
8.1.1 Requirements .13
8.1.2 Test method .13
8.2 Battery power supply.14
8.2.1 Requirements .14
8.2.2 Test method .14
8.3 Warm-up time.14
8.3.1 Requirements .14
8.3.2 Test method .14
8.4 Radio frequency (RF) requirements .14
8.4.1 Requirements .14
8.4.2 Test method .15

62438 © IEC:2010 – 3 –
8.5 RF susceptibility.15
8.5.1 Requirements .15
8.5.2 Test method .15
8.6 Temperature.15
8.6.1 Requirements .15
8.6.2 Test method .15
8.7 Relative Humidity .15
8.7.1 Requirements .15
8.7.2 Test method .15
8.8 Shock (operating) .16
8.8.1 Requirements .16
8.8.2 Test method .16
8.9 Vibration (operating).16
8.9.1 Requirements .16
8.9.2 Test method .16
8.10 Vibration (non-operating).16
8.10.1 Requirements .16
8.10.2 Test method .16
8.11 Water resistance .16
8.11.1 Requirements .16
8.11.2 Test method .16
8.12 Temperature effects .17
8.12.1 Requirements .17
8.12.2 Test method .17
8.13 Summed detector resolution .17
8.13.1 Requirements .17
8.13.2 Test method .17
9 Scintillation based detector module requirements .17
9.1 Photomultiplier count rate stability.17
9.1.1 Requirements .17
9.1.2 Test method .17
9.2 Photomultiplier magnetic shielding .17
9.2.1 Requirements .17
9.2.2 Test method .17
10 High purity germanium (HPGE) detector requirements.17
10.1 Spectrum requirements .17
10.2 Test method .18
11 Neutron detector requirements .18
11.1 Neutrons .18
11.1.1 Requirements .18
11.1.2 Test method .18
11.2 Shock and vibration.18
11.2.1 Requirements .18
11.2.2 Test method .18
11.3 Strong gamma ray field .18
11.3.1 Requirements .18
11.3.2 Test method .18
11.4 Measurement time reference .18
11.4.1 Requirements .18

– 4 – 62438 © IEC:2010
11.4.2 Test method .18
12 Specific test for preamplifier and ADC modules for spectrum-capable detectors .19
12.1 Spectral gain stability .19
12.1.1 Requirements .19
12.1.2 Test method .19
12.2 Livetime reference.19
12.2.1 Requirements .19
12.2.2 Test method .19
12.3 ADC .19
12.3.1 Requirements .19
12.3.2 Test method .19
12.4 Linearity of count rate response .19
12.4.1 Requirements .19
12.4.2 Test method .19
13 Spectral specifications and test requirements for spectrum capable detectors .20
13.1 Multicrystal array performance .20
13.1.1 Requirements .20
13.1.2 Test method .20
13.2 Spectrum recording .20
13.2.1 Requirements .20
13.2.2 Test method .20
13.3 Data transfer .20
13.3.1 Requirements .20
13.3.2 Test method .20
13.4 Synchronisation of acquisition periods.20
13.4.1 Requirements .20
13.4.2 Test method .20
13.5 Synchronisation with positional information .20
13.5.1 Requirements .20
13.5.2 Test method .20
13.6 Synchronisation with height above ground surface information .21
13.6.1 Requirements .21
13.6.2 Test method .21
14 Data logging .21
14.1 Time referencing .21
14.1.1 Requirements .21
14.1.2 Test method .21
15 Installation requirement minimising shielding from the platform for internally
mounted detectors.21
15.1 Requirements.21
15.2 Test method .21
16 Additional requirements.21
16.1 General .21
16.2 Real time data display requirements.22
17 Documentation .22
17.1 Instructions manual .22
17.2 Test certificate .22
18 Safety requirements .22

62438 © IEC:2010 – 5 –
Annex A (informative) Data processing .24
Annex B (informative) A typical analysis scenario for natural (K(potassium) U(uranium)
T(thorium)) extraction only .27
Annex C (informative) Structured sampling plans for reference soils .31
Annex D (informative) Mechanical performance requirements .36
Bibliography.37

Figure 1 – Schematic diagram of the typical components of a mobile platform system .11
Figure C.1 – The expanding hexagonal sampling and typical sampling sets A and B.31
Figure C.2 – Coincidence between the area of investigation for Cs and the
hexagonal sampling plan .33

Table 1 – Typical detector deployment for different applications .11
Table 2 – RF emission limits measured at 3 m distance from the assembly.15
Table 3 – Reference conditions and standard test conditions .22
Table 4 – Tests performed under standard test conditions .23
Table 5 – Tests performed with variation of influence quantities.23
Table A.1 Conversion values between natural radionuclide concentrations and Kerma
rate in air .25
Table C.1 – Weighting for each hexagonal shell with radionuclide energy and detector
altitude .32
Table C.2 – The spatially weighted mean activities for Cs at Caerlaverock sampling
site for detector altitudes at 1 m, 50 m and 100 m.34
Table C.3 – Comparison of derived calibration coefficients from hexagonal calibration
sites (all errors quoted as 1σ standard error except which is 1σ standard deviation) .35
Table D.1 – Vibration break points .36

– 6 – 62438 © IEC:2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RADIATION PROTECTION INSTRUMENTATION –
MOBILE INSTRUMENTATION FOR THE MEASUREMENT OF PHOTON
AND NEUTRON RADIATION IN THE ENVIRONMENT

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,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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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.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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 62438 has been prepared by subcommittee 45B: Radiation
protection instrumentation, of IEC technical committee 45: Nuclear instrumentation.
This standard cancels and replaces IEC 61134, issued in 1992. The scope of IEC 61134 was
restricted to exploration for geological deposits of potassium, uranium and thorium.
IEC 62438 incorporates the range of currently available detector technologies and
incorporates neutron monitoring. This standard also relates to a wide range of mobile platform
applications including environmental, emergency response, security in addition to geological.
The text of this standard is based on the following documents:
FDIS Report on voting
45B/633/FDIS 45B/636/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.

62438 © IEC:2010 – 7 –
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.
– 8 – 62438 © IEC:2010
RADIATION PROTECTION INSTRUMENTATION –
MOBILE INSTRUMENTATION FOR THE MEASUREMENT OF PHOTON
AND NEUTRON RADIATION IN THE ENVIRONMENT

1 Scope and object
This International Standard is applicable to mobile radiation detection systems used for the
detection, quantification and identification of photon and/or neutron emitters in the
environment. This includes point and distributed radiation sources.
The object of this standard is to:
• establish definitions;
• establish minimum requirements for the instrumentation;
• establish requirements for deployment and operations;
• provide test and calibration methods; and
• provide guidance to procurement for appropriate equipment.
In general, mobile instrumentation systems for nuclear radiation measurements in the
environment are comprised of detectors, detector signal processors, position sensing devices,
on-board data recording, operational monitoring, and real time display/alarm capabilities. In
addition, advanced systems may provide data streams that can be transmitted by telemetry to
operations centres.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60050-393:2003, International Electrotechnical Vocabulary (IEV) – Chapter 393: Nuclear
instrumentation – Physical phenomena and basic concepts
IEC 60050-394:2007, International Electrotechnical Vocabulary (IEV) – Part 394: Nuclear
instrumentation – Instruments, systems, equipment and detectors
IEC 60068-1:1988, Environmental testing – Part 1: General and guidance
IEC 60068-2-6:2007, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-14:2009, Environmental testing – Part 2-14: Tests – Test N: Change of
temperature
IEC 60068-2-30:2005, Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic
(12 h + 12 h cycle)
IEC 60086 (all parts), Primary batteries
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60973:1989, Test procedures for germanium gamma-ray detectors

62438 © IEC:2010 – 9 –
IEC 61010-1:2001, Safety requirements for electrical equipment for measurement, control and
laboratory use
IEC 62534, Radiation protection instrumentation – Highly sensitive hand-held instruments for
neutron detection of radioactive material
ISO 4037 (all parts), X and gamma reference radiation for calibrating dosemeters and
doserate meters and for determining their response as a function of photon energy
ISO 6980 (all parts), Nuclear energy – Reference beta-particle radiation
3 Terms, definitions and nomenclature
3.1 Definitions
For the purposes of this document, the following terms and definitions apply. Except as
specified below, all technical terms are as defined in IEC 60050, particularly for radiation
quantities and dosimetric terms defined in IEC 60050-393 and IEC 60050-394.
3.1.1 mobile detection system
mobile detection systems consist of a suitable number of radiation detectors mounted on an
transportable platform, which are capable of making measurements while moving (see
Figure 1).
NOTE This may include but is not limited to fixed and rotary winged aircraft, surface vehicles, ocean towing, and
amphibious vehicles.
3.1.2 energy resolution
the full width in percent or keV at half maximum at a defined total absorption peak (see Annex
A)
3.1.3 background (intrinsic, platform and cosmic)
the measured count rate from photons in an energy spectrum or a given energy window or the
measured count rate from neutrons from the detection system, platform and cosmic radiation
(see Annex A)
3.1.4 positional reference
the spatial reference which defines the location of the detection system in terms of a
coordinate system and where necessary, altitude and the height above the surface
3.1.5 area of investigation
the area from which 90 % of the detected photons and neutrons of interest are emitted,
assuming a planar surface of uniform activity
3.1.6 sampling interval
the time in seconds between the start of consecutive data samples or measurements. This is
also known as the integration time
—————————
To be published.
– 10 – 62438 © IEC:2010
3.1.7 reference soil or surface
an area of soil or surface that has been characterized for empirical calibration of the mobile
system (see Annex C)
3.1.8 platform
for the purposes of this standard, platform refers to carrying system including aircraft, truck
or person
3.2 Test nomenclature
3.2.1 qualification tests
tests performed in order to verify that the requirements of a specification are fulfilled.
Qualification tests are divided into type tests and routine tests.
a) type test: A test of one or more devices made to a certain design to show that the design
meets certain specifications.
b) routine test: A test to which each individual device is subjected during or after
manufacture to ascertain whether it complies with certain criteria.
3.2.2 acceptance test
a contractual test to prove to the customer that the device meets certain conditions of its
specifications
[IEV 151-04-20]
4 General system configuration
The measurement system should consist of:
• A primary detection system that has variable sampling intervals (typically between 1 s and
5 s) providing sufficient detector response to enable the detection, identification, and
quantification of radionuclides of interest.
• Navigation system to continuously measure the position of the detection system, enabling
spatial resolution for mapping. For ground systems inertial navigation may be required in
areas where there is poor GPS coverage.
• Power supply for the detection system that may be part of the mobile platform or self-
contained.
• Multi-channel analyzer(s) for photon pulse height analysis with algorithms to provide
radionuclide identification.
• A data acquisition system that collects and stores radiation detection data, positional
information, time, and provides user interface and real-time display.
• Software for data viewing and basic analysis.
The measurement system may also include:
• A neutron detector to record the gross neutron count rate.
• For airborne systems these should also include radar altitude and may also include
ambient temperature, humidity and pressure, wind speed and direction.
For information purposes, primary detection systems comprise large volume NaI(Tl) detectors,
although other scintillators may also be considered. For emergency response purposes,
organic scintillators may also be considered for mapping total gamma emission.

62438 © IEC:2010 – 11 –
Figure 1 provides an example of a typical detection system.
Examples of detector deployment are given in Table 1 below.
Table 1 – Typical detector deployment for different applications
Application Typical instrument deployment Example radionuclides of
interest
137 60
Baseline environmental survey NaI(Tl) and/or HPGe Cs, Co, U, Th, K,
Geological survey NaI(Tl) U, Th, K
137 60 241
Emergency response NaI(Tl), HPGe, organic scintillator, Cs, Co, Am, Pu,
3 131
He proportional counters, other I, neutrons
suitable neutron detectors, and/or
any combination
Output display
GPS
Real time
telemetry
(optional)
Additional
inputs
Na (TI) array
Data aquisition
Data storage
LV
Power supply
EHV
Neutron detector
(optional)
Radar altimeter
(optional)
One or more HPGe
detectors (optional)
IEC  474/10
Figure 1 – Schematic diagram of the typical components of a mobile platform system
5 General requirements
5.1 Power supply
The system should be designed to accept universal power 12-48 V d.c. and/or 100-240 V a.c.
(50-60 Hz).
– 12 – 62438 © IEC:2010
5.2 Battery power supply
When power is supplied by batteries, the capacity of these shall be such that, after at least
8 h of continuous use during operation under standard test conditions, the indication of the
assembly shall remain within ±10 %, other functions remaining within specification. Batteries
as specified in IEC 60086 shall be used.
5.3 Cabling and connections
Connectors and cabling shall be used that are appropriate for the platform and deployment.
5.4 Shock (operating)
–2
The system shall withstand shocks of 300 ms (see Table 4).
5.5 Vibration (operating)
The system shall withstand and operate during vibration at 10-55 Hz, with a total
–2
displacement of 0,075 mm at 10 ms (see Table 4).
5.6 Vibration (non-operating)
The system shall perform within specification after being subjected to vibration (see Table 4).
5.7 Water resistance
Externally mounted detectors shall be water resistant.
5.8 Spectrometric systems
For low resolution detectors such as NaI(Tl), the analogue to digital converter (ADC) shall
have a minimum of 512 channels. For medium resolution detectors such as Cadmium Zinc
Telluride (CZT), the ADC shall have a minimum of 1 024 channels. For high resolution
detectors such as HPGe, the ADC shall have a minimum of 4 096 channels.
6 Classification of the performance characteristics
The limits of variation in the indication of an assembly are specified for each performance
characteristic in Tables 4 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, installation and construction of the instruments do not allow
carrying out the tests of the complete system as a whole by means of the existing test
equipment, then each component may be tested separately in conformity with the present
standard followed by a complete check of the entire system under normal installation and
operating conditions. The procedure used for the test shall be specified.
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 3.2.1). Certain tests may be considered acceptance tests
by agreement between the manufacturer and the purchaser (see 3.2.2).

62438 © IEC:2010 – 13 –
7.2 Reference conditions and standard test conditions
Reference conditions are given in the second column of Table 3. 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 3. For those tests carried out under standard test conditions
given in Table 4 the values of temperature, pressure and relative humidity at the time of test
shall be stated and the appropriate corrections made to give the response under reference
conditions.
For those tests intended to determine the effects of variations in the influence quantities given
in Table 3, the tests listed in Table 5 all other influence quantities shall be maintained within
the limits for standard test conditions given in Table 4, 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 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 measurements may be estimated with sufficient accuracy
to determine whether the requirements for the characteristic under test are met. The interval
between such readings shall be sufficient to ensure that the readings are statistically
independent.
7.5 Reference radiation
Unless otherwise specified in the individual methods of test, all tests involving the use of
137 60 241
gamma radiation shall be carried out with the nuclide Cs, Co and/or Am (see Table 3).
All tests requiring a neutron source shall be carried out with unmoderated Cf. The nature,
construction and conditions of use of the radiation sources shall be in accordance with ISO
4037 for photon radiation and ISO 6980 for neutron radiation.
8 General performance specification and testing requirement
8.1 Power supply
8.1.1 Requirements
The mobile system should be designed to accept universal power 12-48 V d.c. and/or 100-240
V a.c. (50-60 Hz). The indication shall not vary by more than ±10 % over the range of supply
voltages.
8.1.2 Test method
137 60
Place the mobile system in a field of gamma radiation of energy of interest (e.g. Cs or Co)
such that the assembly gives an indication that is approximately three times the background
count rate in the channels corresponding to the total absorption peaks. For each test
accumulate a minimum of 10 000 pulses in the total absorption peak.
With the supply voltage at its nominal value, determine the mean indication (total absorption
peak area) given by the assembly. Determine the mean indication with the supply voltage
10 % above the nominal value and also the mean indication with the supply voltage 12 %
below the nominal value. These mean values shall not differ from that obtained with nominal

– 14 – 62438 © IEC:2010
supply voltage by more than ±10 %. With the frequency varied by ±3 Hz from the nominal
frequency, the readings should not differ by more than ±10 % from that at the nominal
frequency. The above tests shall then be repeated at an incident flux sufficient for the
assembly to give an indication of at least two-thirds o
...