Measurement of radioactivity - Gamma-ray emitting radionuclides - Generic test method using gamma-ray spectrometry (ISO 20042:2019)

This document describes the methods for determining the activity in becquerel (Bq) of gamma‑ray emitting radionuclides in test samples by gamma-ray spectrometry. The measurements are carried out in a testing laboratory following proper sample preparation. The test samples can be solid, liquid or gaseous. Applications include:
—          routine surveillance of radioactivity released from nuclear installations or from sites discharging enhanced levels of naturally occurring radioactive materials;
—          contributing to determining the evolution of radioactivity in the environment;
—          investigating accident and incident situations, in order to plan remedial actions and monitor their effectiveness;
—          assessment of potentially contaminated waste materials from nuclear decommissioning activities;
—          surveillance of radioactive contamination in media such as soils, foodstuffs, potable water, groundwaters, seawater or sewage sludge;
—          measurements for estimating the intake (inhalation, ingestion or injection) of activity of gamma-ray emitting radionuclides in the body.
It is assumed that the user of this document has been given information on the composition of the test sample or the site. In some cases, the radionuclides for analysis have also been specified if characteristic limits are needed. It is also assumed that the test sample has been homogenised and is representative of the material under test.
General guidance is included for preparing the samples for measurement. However, some types of sample are to be prepared following the requirements of specific standards referred to in this document. The generic recommendations can also be useful for the measurement of gamma-ray emitters in situ.
This document includes generic advice on equipment selection (see Annex A), detectors (more detailed information is included in Annex D), and commissioning of instrumentation and method validation. Annex F summarises the influence of different measurement parameters on results for a typical gamma-ray spectrometry system. Quality control and routine maintenance are also covered, but electrical testing of the detector and pulse processing electronics is excluded. It is assumed that any data collection and analysis software used has been written and tested in accordance with relevant software standards such as ISO/IEC/IEEE 12207.
Calibration using reference sources and/or numerical methods is covered, including verification of the results. It also covers the procedure to estimate the activity content of the sample (Bq) from the spectrum.
The principles set out in this document are applicable to measurements by gamma-ray spectrometry in testing laboratories and in situ. However, the detailed requirements for in situ measurement are given in ISO 18589-7 and are outside the scope of this document.
This document covers, but is not restricted to, gamma-ray emitters which emit photons in the energy range of 5 keV to 3 000 keV. However, most of the measurements fall into the range 40 keV to 2 000 keV. The activity (Bq) ranges from the low levels (sub-Bq) found in environmental samples to activities found in accident conditions and high level radioactive wastes.

Bestimmung der Radioaktivität - Gammastrahlung emittierende Radionuklide - Allgemeines Messverfahren mittels Gammaspektrometrie (ISO 20042:2019)

Dieses Dokument beschreibt die Verfahren zur Bestimmung der Aktivität (in Bq) von Gammastrahlung emit¬tierenden Radionukliden in Prüfproben mittels Gammaspektrometrie. Die Messungen werden nach geeigne¬ter Probenvorbereitung in einem Prüflaboratorium durchgeführt. Die Prüfproben können fest, flüssig oder gasförmig sein. Hierzu gehören die folgenden Anwendungen:
–   Routineüberwachung der von kerntechnischen Anlagen oder von Orten, die erhöhte Konzentrationen von natürlich auftretenden radioaktiven Stoffen ableiten, freigesetzten Radioaktivität;
–   Beiträge zur Bestimmung der Ausbreitung von Radioaktivität in der Umgebung;
–   Untersuchung von Unfällen und Zwischenfällen mit dem Ziel, Sanierungsmaßnahmen zu planen und deren Effektivität zu überwachen;
–   Beurteilung von möglicherweise kontaminierten Reststoffen aus den Hinterlassenschaften bei der Still¬legung kerntechnischer Anlagen;
–   Überwachung von radioaktiven Kontaminationen in Materialien wie z. B. Böden, Lebensmitteln, Trink-wasser, Grundwasser, Meerwasser oder Klärschlamm;
–   Messungen zur Abschätzung der Aktivitätsaufnahme (durch Inhalation, Ingestion oder Injektion) von Gammastrahlung emittierenden Radionukliden in den Körper.
Es wird davon ausgegangen, dass der Anwender dieses Dokuments Informationen zur Zusammensetzung der Prüfproben oder des Geländes erhalten hat. In einigen Fällen sind die zu analysierenden Radionuklide angegeben, falls charakteristische Grenzen erforderlich sind. Es wird ebenfalls angenommen, dass die Prüf¬proben homogenisiert und repräsentativ für das zu prüfende Material sind.
Es sind allgemeine Anleitungen zur Vorbehandlung der Proben für die Messungen enthalten. Jedoch müssen einige Probenarten nach den Anforderungen von speziellen Normen, auf die in diesem Dokument verwie¬sen wird, vorbereitet werden. Die allgemeinen Empfehlungen können auch für die Vor-Ort-Messung von Gamma¬strahlern hilfreich sein.
Dieses Dokument beinhaltet allgemeine Empfehlungen für die Auswahl von Geräten (siehe Anhang A), Detektoren (weitere detailliertere Informationen sind im Anhang D enthalten) und für die Inbetriebnahme von Geräten und der Validierung von Verfahren. Anhang F fasst für typische Gammaspektrometriesysteme die Einflüsse verschiedener Messparameter auf deren Ergebnisse zusammen. Qualitätskontrolle und routine¬mäßige Wartung werden ebenfalls abgedeckt, aber die elektrische Prüfung des Detektors und der Elektronik zur Pulsverarbeitung werden nicht behandelt. Es wird angenommen, dass jedwede verwendete Software zur Datensammlung und zur Analyse in Übereinstimmung mit relevanten Software-Normen, wie z. B. ISO/IEC/IEEE 12207, geschrieben und geprüft wurde.
Die Kalibrierung unter Verwendung von Referenzquellen und/oder numerischen Verfahren wird abgedeckt, einschließlich der Verifizierung der Ergebnisse. Es beinhaltet auch das Verfahren zur Abschätzung des Akti¬vitätsgehalts der Probe (in Bq) aus dem Spektrum.
Die Grundsätze, die in diesem Dokument aufgestellt werden, sind anwendbar auf Messungen mittels Gam¬maspektrometrie in Prüflaboratorien und bei Feldmessungen (In-situ-Messungen). Detaillierte Anforderungen für die Messung mittels In-situ-Gammaspektromerie werden jedoch in ISO 18589-7 beschrieben und liegen außerhalb des Anwendungsbereichs dieses Dokuments.
Dieses Dokument deckt unter anderem Gammastrahler, die Photonen im Energiebereich von 5 keV bis 3 000 keV emittieren, ab. Die Mehrzahl der Messungen fällt jedoch in den Bereich von 40 keV bis 2 000 keV. Die Aktivität (in Bq) reicht von niedrigen Niveaus (im Sub-Bq-Bereich), wie sie bei Umweltproben gefunden werden, bis zu Aktivitäten, die bei Unfallbedingungen und in hochradioaktiven Abfällen gefunden werden.

Mesurage de la radioactivité - Radionucléides émetteurs gamma - Méthode d’essai générique par spectrométrie gamma (ISO 20042:2019)

Le présent document décrit les méthodes permettant de déterminer l'activité, exprimée en becquerel (Bq), des radionucléides émetteurs gamma dans des échantillons pour essai, par spectrométrie gamma. Les mesurages sont réalisés dans un laboratoire d'essai après une préparation appropriée des échantillons. Les échantillons pour essai peuvent se présenter sous forme solide, liquide ou gazeuse. Les applications comprennent:
—          la surveillance en routine de la radioactivité émise par les installations nucléaires ou des sites rejetant des niveaux accrus de matières radioactives naturellement présentes;
—          la contribution à la détermination de l'évolution de la radioactivité dans l'environnement;
—          l'investigation en situations d'accident et d'incident, afin de planifier des actions correctives et de surveiller leur efficacité;
—          l'évaluation des déchets potentiellement contaminés issus des activités de déclassement nucléaire;
—          la surveillance de la contamination radioactive dans les milieux tels que les sols, les denrées alimentaires, l'eau, les eaux souterraines, l'eau de mer ou les boues résiduaires;
—          les mesurages destinés à estimer l'absorption (inhalation, ingestion ou injection) de l'activité des radionucléides émetteurs gamma par le corps.
Les utilisateurs du présent document sont présumés avoir été informés de la composition de l'échantillon pour essai ou du site. Dans certains cas, les radionucléides à analyser ont également été spécifiés si des limites caractéristiques sont nécessaires. L'hypothèse est également faite que l'échantillon pour essai a été homogénéisé et est représentatif de la matière soumise à essai.
Des recommandations générales sont fournies pour la préparation des échantillons en vue d'un mesurage. Cependant, certains types d'échantillons doivent être préparés conformément aux exigences de normes spécifiques citées en référence dans le présent document. Les recommandations génériques peuvent également s'avérer utiles pour le mesurage d'émetteurs gamma in situ.
Le présent document fournit des conseils génériques sur le choix des équipements (voir l'Annexe A), les détecteurs (l'Annexe D donne des informations plus détaillées), la mise en service de l'instrumentation et la validation de la méthode. L'Annexe F résume l'influence des différents paramètres de mesure sur les résultats pour un système type de spectrométrie gamma. Le contrôle de la qualité et la maintenance de routine sont également traités, mais les essais électriques du détecteur et de l'électronique de traitement des impulsions ne sont pas couverts. Tout logiciel utilisé pour la collecte et l'analyse des données est supposé avoir été écrit et contrôlé conformément aux normes pertinentes sur les logiciels, telles que l'ISO/IEC/IEEE 12207.
L'étalonnage à l'aide de sources de référence et/ou par des méthodes numériques est traité, incluant la vérification des résultats. Le présent document détaille également le mode opératoire permettant d'estimer, à partir du spectre, la valeur de l'activité de l'échantillon (Bq).
Les principes énoncés dans le présent document sont applicables aux mesurages par spectrométrie gamma en laboratoire d'essai et in situ. Cependant, les exigences détaillées relatives au mesurage in situ sont spécifiées dans l'ISO 18589-7 et n'entrent pas dans le domaine d'application du présent document.
Le présent document couvre, mais sans s'y limiter, les émetteurs gamma qui émettent des ph

Merjenje radioaktivnosti - Radionuklidi, ki sevajo žarke gama - Splošna preskusna metoda z uporabo spektrometrije žarkov gama (ISO 20042:2019)

General Information

Status
Published
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
04-Aug-2021
Completion Date
04-Aug-2021

Buy Standard

Standard
EN ISO 20042:2021 - BARVE na PDF-str 22,48,50,54
English language
60 pages
sale 10% off
Preview
sale 10% off
Preview
e-Library read for
1 day
Draft
prEN ISO 20042:2021 - BARVE na PDF-str 44,46,50
English language
57 pages
sale 10% off
Preview
sale 10% off
Preview
e-Library read for
1 day

Standards Content (sample)

SLOVENSKI STANDARD
SIST EN ISO 20042:2021
01-oktober-2021

Merjenje radioaktivnosti - Radionuklidi, ki sevajo žarke gama - Splošna preskusna

metoda z uporabo spektrometrije žarkov gama (ISO 20042:2019)

Measurement of radioactivity - Gamma-ray emitting radionuclides - Generic test method

using gamma-ray spectrometry (ISO 20042:2019)
Bestimmung der Radioaktivität - Gammastrahlung emittierende Radionuklide -
Allgemeines Messverfahren mittels Gammaspektrometrie (ISO 20042:2019)
Mesurage de la radioactivité - Radionucléides émetteurs gamma - Méthode d’essai
générique par spectrométrie gamma (ISO 20042:2019)
Ta slovenski standard je istoveten z: EN ISO 20042:2021
ICS:
13.280 Varstvo pred sevanjem Radiation protection
SIST EN ISO 20042:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 20042:2021
---------------------- Page: 2 ----------------------
SIST EN ISO 20042:2021
EN ISO 20042
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2021
EUROPÄISCHE NORM
ICS 13.280
English Version
Measurement of radioactivity - Gamma-ray emitting
radionuclides - Generic test method using gamma-ray
spectrometry (ISO 20042:2019)

Mesurage de la radioactivité - Radionucléides Bestimmung der Radioaktivität - Gammastrahlung

émetteurs gamma - Méthode d'essai générique par emittierende Radionuklide - Allgemeines

spectrométrie gamma (ISO 20042:2019) Messverfahren mittels Gammaspektrometrie (ISO

20042:2019)
This European Standard was approved by CEN on 25 July 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20042:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 20042:2021
EN ISO 20042:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 20042:2021
EN ISO 20042:2021 (E)
European foreword

The text of ISO 20042:2019 has been prepared by Technical Committee ISO/TC 85 "Nuclear energy,

nuclear technologies, and radiological protection” of the International Organization for Standardization

(ISO) and has been taken over as EN ISO 20042:2021 by Technical Committee CEN/TC 430 “Nuclear

energy, nuclear technologies, and radiological protection” the secretariat of which is held by AFNOR.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by February 2022, and conflicting national standards

shall be withdrawn at the latest by February 2022.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document is read in conjunction with EN XXX.

Any feedback and questions on this document should be directed to the users’ national standards body.

A complete listing of these bodies can be found on the CEN website.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 20042:2019 has been approved by CEN as EN ISO 20042:2021 without any modification.

---------------------- Page: 5 ----------------------
SIST EN ISO 20042:2021
---------------------- Page: 6 ----------------------
SIST EN ISO 20042:2021
INTERNATIONAL ISO
STANDARD 20042
First edition
2019-06
Measurement of radioactivity —
Gamma-ray emitting radionuclides —
Generic test method using gamma-ray
spectrometry
Mesurage de la radioactivité — Radionucléides émetteurs de
rayons gamma — Méthode d’essai générique par spectrométrie à
rayons gamma
Reference number
ISO 20042:2019(E)
ISO 2019
---------------------- Page: 7 ----------------------
SIST EN ISO 20042:2021
ISO 20042:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 20042:2021
ISO 20042:2019(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

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

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols and units ............................................................................................................................................................................................... 5

5 Principle ........................................................................................................................................................................................................................ 6

5.1 General ........................................................................................................................................................................................................... 6

5.2 Summing method .................................................................................................................................................................................. 6

5.3 Fitting method ......................................................................................................................................................................................... 7

6 Validating measurements by gamma-ray spectrometry ............................................................................................. 7

6.1 General ........................................................................................................................................................................................................... 7

6.2 Step 1: customer requirements ................................................................................................................................................ 8

6.3 Step 2: technical requirements ................................................................................................................................................. 8

6.4 Step 3: detailed design ..................................................................................................................................................................10

6.5 Step 4: installation ............................................................................................................................................................................10

6.6 Step 5: validation studies ............................................................................................................................................................10

6.7 Step 6: robustness .............................................................................................................................................................................11

6.8 Step 7: operation and maintenance ...................................................................................................................................11

7 Nuclear decay data ..........................................................................................................................................................................................11

7.1 Recommended nuclear decay data .....................................................................................................................................11

7.2 Selection of gamma-ray photopeaks for inclusion in spectrum analysis libraries ....................12

7.3 Decay chains ...........................................................................................................................................................................................12

8 Detector energy and efficiency calibration ............................................................................................................................13

8.1 Energy calibration .............................................................................................................................................................................13

8.2 Efficiency calibration ......................................................................................................................................................................13

8.3 Source(s) for energy calibration ...........................................................................................................................................14

8.4 Reference source(s) for efficiency calibration ..........................................................................................................15

8.4.1 General...................................................................................................................................................................................15

8.4.2 Reference sources for laboratory systems ..............................................................................................15

8.4.3 Reference sources used with numerical methods ...........................................................................15

9 Sample container ..............................................................................................................................................................................................15

10 Procedure..................................................................................................................................................................................................................16

10.1 Sample measuring procedure .................................................................................................................................................16

10.1.1 Sampling...............................................................................................................................................................................16

10.1.2 Sample preparation ....................................................................................................................................................16

10.1.3 Loading the sample container ...........................................................................................................................18

10.1.4 Recording the sample spectrum ......................................................................................................................18

10.2 Analysis of the spectrum .............................................................................................................................................................18

10.2.1 Procedure for laboratory-based measuring systems ....................................................................18

10.2.2 Background corrections .........................................................................................................................................19

11 Expression of results .....................................................................................................................................................................................20

11.1 Calculation of activity and activity per kg (or m ) of sample ......................................................................20

11.2 Determination of the characteristic limits ...................................................................................................................21

12 Test report ................................................................................................................................................................................................................21

Annex A (informative) Quality assurance and quality control program ......................................................................22

Annex B (informative) Corrections to the analysis process .......................................................................................................24

Annex C (informative) Uncertainty budget .................................................................................................................................................29

© ISO 2019 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 20042:2021
ISO 20042:2019(E)

Annex D (informative) Detector types .............................................................................................................................................................32

137

Annex E (informative) Example: Calculation of Cs activity content and characteristic

limits in an aqueous sample ..................................................................................................................................................................35

Annex F (informative) Example: Simulating correction factors for sample positioning,

geometry, matrix, density and true summing .....................................................................................................................40

Bibliography .............................................................................................................................................................................................................................49

iv © ISO 2019 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 20042:2021
ISO 20042:2019(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies,

and radiological protection, SC 2, Radiological protection.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
© ISO 2019 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 20042:2021
ISO 20042:2019(E)
Introduction

Everyone is exposed to natural radiation. The natural sources of radiation are cosmic rays and

naturally occurring radioactive substances which exist in the earth and flora and fauna, including the

human body. Human activities involving the use of radiation and radioactive substances add to the

radiation exposure from this natural exposure. Some of those activities, such as the mining and use

of ores containing naturally-occurring radioactive materials (NORM) and the production of energy

by burning coal that contains such substances, simply enhance the exposure from natural radiation

sources. Nuclear power plants and other nuclear installations use radioactive materials and produce

radioactive effluent and waste during operation and decommissioning. The use of radioactive materials

in industry, agriculture, medicine and research is expanding around the globe.

All these human activities give rise to radiation exposures that are only a small fraction of the global

average level of natural exposure. The medical use of radiation is the largest and a growing man-made

source of radiation exposure in developed countries. It includes diagnostic radiology, radiotherapy,

nuclear medicine and interventional radiology.

Radiation exposure also occurs as a result of occupational activities. It is incurred by workers in

industry, medicine and research using radiation or radioactive substances, as well as by passengers and

crew during air travel. The average level of occupational exposures is generally similar to the global

average level of natural radiation exposure (see Reference [1]).

As uses of radiation increase, so do the potential health risk and the public's concerns. Thus, all these

exposures are regularly assessed in order to,

a) improve the understanding of global levels and temporal trends of public and worker exposure,

b) evaluate the components of exposure so as to provide a measure of their relative importance, and

c) identify emerging issues that may warrant more attention and study.

While doses to workers are mostly measured directly, doses to the public are usually assessed indirectly

using the results of radioactivity measurements of waste, effluent and/or environmental samples.

To ensure that the data obtained from radioactivity monitoring programs support their intended use, it

is essential that the stakeholders (for example nuclear site operators, regulatory and local authorities)

agree on appropriate methods and procedures for obtaining representative samples and for handling,

storing, preparing and measuring the test samples. An assessment of the overall measurement

uncertainty also needs to be carried out systematically. As reliable, comparable and ‘fit for purpose’

data are an essential requirement for any public health decision based on radioactivity measurements,

international standards of tested and validated radionuclide test methods are an important tool for

the production of such measurement results. The application of standards serves also to guarantee

comparability of the test results over time and between different testing laboratories. Laboratories

apply them to demonstrate their technical competences and to complete proficiency tests successfully

during interlaboratory comparisons, two prerequisites for obtaining national accreditation.

Today, over a hundred International Standards are available to testing laboratories for measuring

radionuclides in different matrices.

Generic standards help testing laboratories to manage the measurement process by setting out the

general requirements and methods to calibrate equipment and validate techniques. These standards

underpin specific standards which describe the test methods to be performed by staff, for example, for

different types of sample. The specific standards cover test methods for
40 3 14

— naturally-occurring radionuclides (including K, H, C and those originating from the thorium

226 228 234 238 210

and uranium decay series, in particular Ra, Ra, U, U and Pb) which can be found in

materials from natural sources or can be released from technological processes involving naturally

occurring radioactive materials (e.g. the mining and processing of mineral sands or phosphate

fertilizer production and use), and
vi © ISO 2019 – All rights reserved
---------------------- Page: 12 ----------------------
SIST EN ISO 20042:2021
ISO 20042:2019(E)

— human-made radionuclides, such as transuranium elements (americium, plutonium, neptunium,

3 14 90

and curium), H, C, Sr and gamma-ray emitting radionuclides found in waste, liquid and gaseous

effluent, in environmental matrices (water, air, soil and biota), in food and in animal feed as a result

of authorized releases into the environment, fallout from the explosion in the atmosphere of nuclear

devices and fallout from accidents, such as those that occurred in Chernobyl and Fukushima.

The fraction of the background dose rate to man from environmental radiation, mainly gamma

radiation, is very variable and depends on factors such as the radioactivity of the local rock and soil, the

nature of building materials and the construction of buildings in which people live and work.

A reliable determination of the activity concentration of gamma-ray emitting radionuclides in various

matrices is necessary to assess the potential human exposure, to verify compliance with radiation

protection and environmental protection regulations or to provide guidance on reducing health risks.

Gamma-ray emitting radionuclides are also used as tracers in biology, medicine, physics, chemistry, and

engineering. Accurate measurement of the activities of the radionuclides is also needed for homeland

security and in connection with the Non-Proliferation Treaty (NPT).

This document describes the generic requirements to quantify the activity of gamma-ray-emitting

radionuclides in samples after proper sampling, sample handling and test sample preparation in a

testing laboratory or in situ.

This document is to be used in the context of a quality assurance management system (ISO/IEC 17025).

It forms the basis for measurement tasks using gamma-ray spectrometry, such as those set out in

ISO 18589-3, ISO 18589-7, ISO 10703, ISO 13164-2 and ISO 13165-3.

This document is one of a set of generic International Standards on measurement of radioactivity such

as ISO 19361.
© ISO 2019 – All rights reserved vii
---------------------- Page: 13 ----------------------
SIST EN ISO 20042:2021
---------------------- Page: 14 ----------------------
SIST EN ISO 20042:2021
INTERNATIONAL STANDARD ISO 20042:2019(E)
Measurement of radioactivity — Gamma-ray emitting
radionuclides — Generic test method using gamma-ray
spectrometry
1 Scope

This document describes the methods for determining the activity in becquerel (Bq) of gamma-ray

emitting radionuclides in test samples by gamma-ray spectrometry. The measurements are carried out

in a testing laboratory following proper sample preparation. The test samples can be solid, liquid or

gaseous. Applications include:

— routine surveillance of radioactivity released from nuclear installations or from sites discharging

enhanced levels of naturally occurring radioactive materials;
— contributing to determining the evolution of radioactivity in the environment;

— investigating accident and incident situations, in order to plan remedial actions and monitor their

effectiveness;

— assessment of potentially contaminated waste materials from nuclear decommissioning activities;

— surveillance of radioactive contamination in media such as soils, foodstuffs, potable water,

groundwaters, seawater or sewage sludge;

— measurements for estimating the intake (inhalation, ingestion or injection) of activity of gamma-

ray emitting radionuclides in the body.

It is assumed that the user of this document has been given information on the composition of the test

sample or the site. In some cases, the radionuclides for analysis have also been specified if characteristic

limits are needed. It is also assumed that the test sample has been homogenised and is representative of

the material under test.

General guidance is included for preparing the samples for measurement. However, some types of sample

are to be prepared following the requirements of specific standards referred to in this document. The

generic recommendations can also be useful for the measurement of gamma-ray emitters in situ.

This document includes generic advice on equipment selection (see Annex A), detectors (more detailed

information is included in Annex D), and commissioning of instrumentation and method validation.

Annex F summarises the influence of different measurement parameters on results for a typical

gamma-ray spectrometry system. Quality control and routine maintenance are also covered, but

electrical testing of the detector and pulse processing electronics is excluded. It is assumed that any

data collection and analysis software used has been written and tested in accordance with relevant

software standards such as ISO/IEC/IEEE 12207.

Calibration using reference sources and/or numerical methods is covered, including verification of

the results. It also covers the procedure to estimate the activity content of the sample (Bq) from the

spectrum.

The principles set out in this document are applicable to measurements by gamma-ray spectrometry in

testing laboratories and in situ. However, the detailed requirements for in situ measurement are given

in ISO 18589-7 and are outside the scope of this document.

This document covers, but is not restricted to, gamma-ray emitters which emit photons in the energy

range of 5 keV to 3 000 keV. However, most of the measurements fall into the range 40 keV to 2 000 keV.

The activity (Bq) ranges from the low levels (sub-Bq) found in environmental samples to activities

found in accident conditions and high level radioactive wastes.
© ISO 2019 – All rights reserved 1
---------------------- Page: 15 ----------------------
SIST EN ISO 20042:2021
ISO 20042:2019(E)
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

ISO 542, Oilseeds — Sampling
ISO 707, Milk and milk products — Guidance on sampling
ISO 5500, Oilseed residues — Sampling
ISO 5538, Milk and milk products — Sampling — Inspection by attributes

ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and

sampling techniques
ISO 5667-
...

SLOVENSKI STANDARD
oSIST prEN ISO 20042:2021
01-junij-2021

Merjenje radioaktivnosti - Radionuklidi, ki sevajo žarke gama - Splošna preskusna

metoda z uporabo spektrometrije žarkov gama (ISO 20042:2019)

Measurement of radioactivity - Gamma-ray emitting radionuclides - Generic test method

using gamma-ray spectrometry (ISO 20042:2019)
Mesurage de la radioactivité - Radionucléides émetteurs gamma - Méthode d’essai
générique par spectrométrie gamma (ISO 20042:2019)
Ta slovenski standard je istoveten z: prEN ISO 20042
ICS:
13.280 Varstvo pred sevanjem Radiation protection
oSIST prEN ISO 20042:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 20042:2021
---------------------- Page: 2 ----------------------
oSIST prEN ISO 20042:2021
INTERNATIONAL ISO
STANDARD 20042
First edition
2019-06
Measurement of radioactivity —
Gamma-ray emitting radionuclides —
Generic test method using gamma-ray
spectrometry
Mesurage de la radioactivité — Radionucléides émetteurs de
rayons gamma — Méthode d’essai générique par spectrométrie à
rayons gamma
Reference number
ISO 20042:2019(E)
ISO 2019
---------------------- Page: 3 ----------------------
oSIST prEN ISO 20042:2021
ISO 20042:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 20042:2021
ISO 20042:2019(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

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

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols and units ............................................................................................................................................................................................... 5

5 Principle ........................................................................................................................................................................................................................ 6

5.1 General ........................................................................................................................................................................................................... 6

5.2 Summing method .................................................................................................................................................................................. 6

5.3 Fitting method ......................................................................................................................................................................................... 7

6 Validating measurements by gamma-ray spectrometry ............................................................................................. 7

6.1 General ........................................................................................................................................................................................................... 7

6.2 Step 1: customer requirements ................................................................................................................................................ 8

6.3 Step 2: technical requirements ................................................................................................................................................. 8

6.4 Step 3: detailed design ..................................................................................................................................................................10

6.5 Step 4: installation ............................................................................................................................................................................10

6.6 Step 5: validation studies ............................................................................................................................................................10

6.7 Step 6: robustness .............................................................................................................................................................................11

6.8 Step 7: operation and maintenance ...................................................................................................................................11

7 Nuclear decay data ..........................................................................................................................................................................................11

7.1 Recommended nuclear decay data .....................................................................................................................................11

7.2 Selection of gamma-ray photopeaks for inclusion in spectrum analysis libraries ....................12

7.3 Decay chains ...........................................................................................................................................................................................12

8 Detector energy and efficiency calibration ............................................................................................................................13

8.1 Energy calibration .............................................................................................................................................................................13

8.2 Efficiency calibration ......................................................................................................................................................................13

8.3 Source(s) for energy calibration ...........................................................................................................................................14

8.4 Reference source(s) for efficiency calibration ..........................................................................................................15

8.4.1 General...................................................................................................................................................................................15

8.4.2 Reference sources for laboratory systems ..............................................................................................15

8.4.3 Reference sources used with numerical methods ...........................................................................15

9 Sample container ..............................................................................................................................................................................................15

10 Procedure..................................................................................................................................................................................................................16

10.1 Sample measuring procedure .................................................................................................................................................16

10.1.1 Sampling...............................................................................................................................................................................16

10.1.2 Sample preparation ....................................................................................................................................................16

10.1.3 Loading the sample container ...........................................................................................................................18

10.1.4 Recording the sample spectrum ......................................................................................................................18

10.2 Analysis of the spectrum .............................................................................................................................................................18

10.2.1 Procedure for laboratory-based measuring systems ....................................................................18

10.2.2 Background corrections .........................................................................................................................................19

11 Expression of results .....................................................................................................................................................................................20

11.1 Calculation of activity and activity per kg (or m ) of sample ......................................................................20

11.2 Determination of the characteristic limits ...................................................................................................................21

12 Test report ................................................................................................................................................................................................................21

Annex A (informative) Quality assurance and quality control program ......................................................................22

Annex B (informative) Corrections to the analysis process .......................................................................................................24

Annex C (informative) Uncertainty budget .................................................................................................................................................29

© ISO 2019 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 20042:2021
ISO 20042:2019(E)

Annex D (informative) Detector types .............................................................................................................................................................32

137

Annex E (informative) Example: Calculation of Cs activity content and characteristic

limits in an aqueous sample ..................................................................................................................................................................35

Annex F (informative) Example: Simulating correction factors for sample positioning,

geometry, matrix, density and true summing .....................................................................................................................40

Bibliography .............................................................................................................................................................................................................................49

iv © ISO 2019 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 20042:2021
ISO 20042:2019(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies,

and radiological protection, SC 2, Radiological protection.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
© ISO 2019 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 20042:2021
ISO 20042:2019(E)
Introduction

Everyone is exposed to natural radiation. The natural sources of radiation are cosmic rays and

naturally occurring radioactive substances which exist in the earth and flora and fauna, including the

human body. Human activities involving the use of radiation and radioactive substances add to the

radiation exposure from this natural exposure. Some of those activities, such as the mining and use

of ores containing naturally-occurring radioactive materials (NORM) and the production of energy

by burning coal that contains such substances, simply enhance the exposure from natural radiation

sources. Nuclear power plants and other nuclear installations use radioactive materials and produce

radioactive effluent and waste during operation and decommissioning. The use of radioactive materials

in industry, agriculture, medicine and research is expanding around the globe.

All these human activities give rise to radiation exposures that are only a small fraction of the global

average level of natural exposure. The medical use of radiation is the largest and a growing man-made

source of radiation exposure in developed countries. It includes diagnostic radiology, radiotherapy,

nuclear medicine and interventional radiology.

Radiation exposure also occurs as a result of occupational activities. It is incurred by workers in

industry, medicine and research using radiation or radioactive substances, as well as by passengers and

crew during air travel. The average level of occupational exposures is generally similar to the global

average level of natural radiation exposure (see Reference [1]).

As uses of radiation increase, so do the potential health risk and the public's concerns. Thus, all these

exposures are regularly assessed in order to,

a) improve the understanding of global levels and temporal trends of public and worker exposure,

b) evaluate the components of exposure so as to provide a measure of their relative importance, and

c) identify emerging issues that may warrant more attention and study.

While doses to workers are mostly measured directly, doses to the public are usually assessed indirectly

using the results of radioactivity measurements of waste, effluent and/or environmental samples.

To ensure that the data obtained from radioactivity monitoring programs support their intended use, it

is essential that the stakeholders (for example nuclear site operators, regulatory and local authorities)

agree on appropriate methods and procedures for obtaining representative samples and for handling,

storing, preparing and measuring the test samples. An assessment of the overall measurement

uncertainty also needs to be carried out systematically. As reliable, comparable and ‘fit for purpose’

data are an essential requirement for any public health decision based on radioactivity measurements,

international standards of tested and validated radionuclide test methods are an important tool for

the production of such measurement results. The application of standards serves also to guarantee

comparability of the test results over time and between different testing laboratories. Laboratories

apply them to demonstrate their technical competences and to complete proficiency tests successfully

during interlaboratory comparisons, two prerequisites for obtaining national accreditation.

Today, over a hundred International Standards are available to testing laboratories for measuring

radionuclides in different matrices.

Generic standards help testing laboratories to manage the measurement process by setting out the

general requirements and methods to calibrate equipment and validate techniques. These standards

underpin specific standards which describe the test methods to be performed by staff, for example, for

different types of sample. The specific standards cover test methods for
40 3 14

— naturally-occurring radionuclides (including K, H, C and those originating from the thorium

226 228 234 238 210

and uranium decay series, in particular Ra, Ra, U, U and Pb) which can be found in

materials from natural sources or can be released from technological processes involving naturally

occurring radioactive materials (e.g. the mining and processing of mineral sands or phosphate

fertilizer production and use), and
vi © ISO 2019 – All rights reserved
---------------------- Page: 8 ----------------------
oSIST prEN ISO 20042:2021
ISO 20042:2019(E)

— human-made radionuclides, such as transuranium elements (americium, plutonium, neptunium,

3 14 90

and curium), H, C, Sr and gamma-ray emitting radionuclides found in waste, liquid and gaseous

effluent, in environmental matrices (water, air, soil and biota), in food and in animal feed as a result

of authorized releases into the environment, fallout from the explosion in the atmosphere of nuclear

devices and fallout from accidents, such as those that occurred in Chernobyl and Fukushima.

The fraction of the background dose rate to man from environmental radiation, mainly gamma

radiation, is very variable and depends on factors such as the radioactivity of the local rock and soil, the

nature of building materials and the construction of buildings in which people live and work.

A reliable determination of the activity concentration of gamma-ray emitting radionuclides in various

matrices is necessary to assess the potential human exposure, to verify compliance with radiation

protection and environmental protection regulations or to provide guidance on reducing health risks.

Gamma-ray emitting radionuclides are also used as tracers in biology, medicine, physics, chemistry, and

engineering. Accurate measurement of the activities of the radionuclides is also needed for homeland

security and in connection with the Non-Proliferation Treaty (NPT).

This document describes the generic requirements to quantify the activity of gamma-ray-emitting

radionuclides in samples after proper sampling, sample handling and test sample preparation in a

testing laboratory or in situ.

This document is to be used in the context of a quality assurance management system (ISO/IEC 17025).

It forms the basis for measurement tasks using gamma-ray spectrometry, such as those set out in

ISO 18589-3, ISO 18589-7, ISO 10703, ISO 13164-2 and ISO 13165-3.

This document is one of a set of generic International Standards on measurement of radioactivity such

as ISO 19361.
© ISO 2019 – All rights reserved vii
---------------------- Page: 9 ----------------------
oSIST prEN ISO 20042:2021
---------------------- Page: 10 ----------------------
oSIST prEN ISO 20042:2021
INTERNATIONAL STANDARD ISO 20042:2019(E)
Measurement of radioactivity — Gamma-ray emitting
radionuclides — Generic test method using gamma-ray
spectrometry
1 Scope

This document describes the methods for determining the activity in becquerel (Bq) of gamma-ray

emitting radionuclides in test samples by gamma-ray spectrometry. The measurements are carried out

in a testing laboratory following proper sample preparation. The test samples can be solid, liquid or

gaseous. Applications include:

— routine surveillance of radioactivity released from nuclear installations or from sites discharging

enhanced levels of naturally occurring radioactive materials;
— contributing to determining the evolution of radioactivity in the environment;

— investigating accident and incident situations, in order to plan remedial actions and monitor their

effectiveness;

— assessment of potentially contaminated waste materials from nuclear decommissioning activities;

— surveillance of radioactive contamination in media such as soils, foodstuffs, potable water,

groundwaters, seawater or sewage sludge;

— measurements for estimating the intake (inhalation, ingestion or injection) of activity of gamma-

ray emitting radionuclides in the body.

It is assumed that the user of this document has been given information on the composition of the test

sample or the site. In some cases, the radionuclides for analysis have also been specified if characteristic

limits are needed. It is also assumed that the test sample has been homogenised and is representative of

the material under test.

General guidance is included for preparing the samples for measurement. However, some types of sample

are to be prepared following the requirements of specific standards referred to in this document. The

generic recommendations can also be useful for the measurement of gamma-ray emitters in situ.

This document includes generic advice on equipment selection (see Annex A), detectors (more detailed

information is included in Annex D), and commissioning of instrumentation and method validation.

Annex F summarises the influence of different measurement parameters on results for a typical

gamma-ray spectrometry system. Quality control and routine maintenance are also covered, but

electrical testing of the detector and pulse processing electronics is excluded. It is assumed that any

data collection and analysis software used has been written and tested in accordance with relevant

software standards such as ISO/IEC/IEEE 12207.

Calibration using reference sources and/or numerical methods is covered, including verification of

the results. It also covers the procedure to estimate the activity content of the sample (Bq) from the

spectrum.

The principles set out in this document are applicable to measurements by gamma-ray spectrometry in

testing laboratories and in situ. However, the detailed requirements for in situ measurement are given

in ISO 18589-7 and are outside the scope of this document.

This document covers, but is not restricted to, gamma-ray emitters which emit photons in the energy

range of 5 keV to 3 000 keV. However, most of the measurements fall into the range 40 keV to 2 000 keV.

The activity (Bq) ranges from the low levels (sub-Bq) found in environmental samples to activities

found in accident conditions and high level radioactive wastes.
© ISO 2019 – All rights reserved 1
---------------------- Page: 11 ----------------------
oSIST prEN ISO 20042:2021
ISO 20042:2019(E)
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

ISO 542, Oilseeds — Sampling
ISO 707, Milk and milk products — Guidance on sampling
ISO 5500, Oilseed residues — Sampling
ISO 5538, Milk and milk products — Sampling — Inspection by attributes

ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and

sampling techniques

ISO 5667-10, Water quality — Sampling — Part 10: Guidance on sampling of waste waters

ISO 10703, Water quality — Determination of the activity concentration of radionuclides — Method by

high resolution gamma-ray spectrometry

ISO 11929, Determination of the characteristic limits (decision threshold, detection limit and limits of the

confidence interval) for measurements of ionizing radiation — Fundamentals and application

ISO 17604, Microbiology of the food chain — Carcass sampling for microbiological analysis

ISO 18400-101, Soil quality — Sampling — Part 101: Framework for the preparation and application of a

sampling plan

ISO 18400-102, Soil quality — Sampling — Part 102: Selection and application of sampling techniques

ISO 18400-103, Soil quality — Sampling — Part 103: Safety
ISO 18400-104, Soil quality — Sampling — Part 104: Strategies
ISO 18400-107, Soil quality — Sampling — Part 107: Recording and reporting
ISO 18400-202, Soil quality — Sampling — Part 202: Preliminary investigations

ISO 18400-203, Soil quality — Sampling — Part 203: Investigation of potentially contaminated sites

ISO 18400-204, Soil quality — Sampling — Part 204: Guidance on sampling of soil gas

ISO 18400-205, Soil quality — Sampling — Part 205: Guidance on the procedure for investigation of

natural, near-natural and cultivated sites

ISO 18589-2, Measurement of radioactivity in the environment — Soil — Part 2: Guidance for the selection

of the sampling strategy, sampling and pre-treatment of samples

ISO 18589-7, Measurement of radioactivity in the environment — Soil — Part 7: In situ measurement of

gamma-emitting radionuclides
ISO 24333, Cereals and cereal products — Sampling

ISO/IEC Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in

measurement (GUM: 1995)

ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2 © ISO 2019 – All rights reserved
---------------------- Page: 12 ----------------------
oSIST prEN ISO 20042:2021
ISO 20042:2019(E)

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
background continuum

events in the spectrum that form a smooth curve onto which the photopeaks are superimposed

Note 1 to entry: The continuum may arise from gamma-rays scattered inside the test sample or any surrounding

materials, from cosmic radiation or from radionuclides in the surrounding materials.

3.2
blank sample

sample of a similar material to the test sample but containing radioactive impurities negligible in

comparison with the test sample
3.3
calcination

thermal treatment of the powder in order to remove volatile impurities or to change the density or

specific surface area of the powder
[SOURCE: ISO 13779-6:2015, 3.4]
Note 1 to entry: Calcination is commonly used for samples such as soil.
3.4
comminution
operation of reducing particle size by crushing, grinding or pulverisation
3.5
dead time

time during spectrum acquisition (real time) during which pulses are not recorded or processed

Note 1 to entry: Dead time is given by real time minus live time.
Note 2 to entry: The time is given in seconds.
3.6
decision threshold

value of the estimator of the measurand, which when exceeded by the result of an actual measurement

using a given measurement procedure of a measurand quantifying a physical effect, one decides that

the physical effect is present
[SOURCE: ISO 11929:2010, 3.6]
3.7
detection efficiency

probability that a gamma-ray emitted at a particular energy (keV) in the decay of a radionuclide in a

test sample is detected in the photopeak corresponding to that energy
3.8
detection limit

smallest true value of the measurand which ensures a specified probability of being detectable by the

measurement procedure
[SOURCE: ISO 11929:2010, 3.7]
© ISO 2019 – All rights reserved 3
---------------------- Page: 13 ----------------------
oSIST prEN ISO 20042:2021
ISO 20042:2019(E)
3.9
fractionation

separation of a product into several fractions by an appropriate technique such as distillation or

crystallization
[SOURCE: ISO 1998-4:1998, 4.20.300]
3.10
full width half maximum
FWHM
width of a gamma-ray p
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.