Radiation protection instrumentation - Determination of uncertainty in measurement (IEC/TR 62461:2015)

This Technical Report gives guidelines for the application of the uncertainty analysis according to ISO/IEC Guide 98-3:2008 (GUM describing an analytical method for the uncertainty determination) and its Supplement 1:2008 (GUM S1 describing a Monte Carlo method for the uncertainty determination) for measurements covered by standards of IEC Subcommittee 45B. It does not include the uncertainty associated with the concept of the measuring quantity, e. g., the difference between Hp(10) on the ISO water slab phantom and on the person.

Strahlenschutz-Messgeräte - Bestimmung der Unsicherheit beim Messen (IEC/TR 62461:2015)

Instrumentation pour la radioprotection – Détermination de l'incertitude de mesure (IEC/TR 62461:2015)

Instrumenti za zaščito pred sevanjem - Določanje merilne negotovosti (IEC/TR 62461:2015)

To tehnično poročilo vsebuje smernice za uporabo analize negotovosti v skladu z Vodilom ISO/IEC 98-3:2008 (GUM, ki opisuje analitično metodo za določanje negotovosti) in njegovim dodatkom 1:2008 (GUM S1, ki opisuje metodo Monte Carlo za določanje negotovosti) za meritve, ki jih vsebujejo standardi pododbora IEC 45B. Ne vključuje negotovosti, povezane s konceptom merilne količine, npr. razlike med Hp(10) na vodnem fantomu ISO in osebi.

General Information

Status
Published
Publication Date
17-Jun-2019
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
12-Jun-2019
Due Date
17-Aug-2019
Completion Date
18-Jun-2019

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SLOVENSKI STANDARD
SIST-TP CLC IEC/TR 62461:2019
01-september-2019
Instrumenti za zaščito pred sevanjem - Določanje merilne negotovosti (IEC/TR
62461:2015)

Radiation protection instrumentation - Determination of uncertainty in measurement

(IEC/TR 62461:2015)
Strahlenschutz-Messgeräte - Bestimmung der Unsicherheit beim Messen (IEC/TR
62461:2015)

Instrumentation pour la radioprotection Détermination de l'incertitude de mesure

(IEC/TR 62461:2015)
Ta slovenski standard je istoveten z: CLC IEC/TR 62461:2019
ICS:
13.280 Varstvo pred sevanjem Radiation protection
SIST-TP CLC IEC/TR 62461:2019 en

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

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SIST-TP CLC IEC/TR 62461:2019
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SIST-TP CLC IEC/TR 62461:2019
TECHNICAL REPORT CLC IEC/TR 62461
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
May 2019
ICS 13.280
English Version
Radiation protection instrumentation - Determination of
uncertainty in measurement
(IEC/TR 62461:2015)

Instrumentation pour la radioprotection - Détermination de Strahlenschutz-Messgeräte - Bestimmung der Unsicherheit

l'incertitude de mesure beim Messen
(IEC/TR 62461:2015) (IEC/TR 62461:2015)
This Technical Report was approved by CENELEC on 2019-05-20.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,

Switzerland, Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. CLC IEC/TR 62461:2019 E
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SIST-TP CLC IEC/TR 62461:2019
CLC IEC/TR 62461:2019 (E)
European foreword

This document (CLC IEC/TR 62461:2019) consists of the text of IEC/TR 62461:2015 prepared by

SC 45B "Radiation protection instrumentation" of IEC/TC 45 "Nuclear instrumentation".

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

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

Endorsement notice

The text of the International Standard IEC/TR 62461:2015 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards

indicated:
IEC 61526:2010 NOTE Harmonized as EN 61526:2013 (modified)
IEC 60846-1:2009 NOTE Harmonized as EN 60846-1:2014 (modified)
IEC 62387:2012 NOTE Harmonized as EN 62387:2016 (modified)
IEC 61005:2003 NOTE Harmonized as EN 61005:2004 (modified)
IEC 61577-2:2014 NOTE Harmonized as EN 61577-2:2017 (modified)
IEC 61577-3:2011 NOTE Harmonized as EN 61577-3:2014 (modified)
IEC 60325:2002 NOTE Harmonized as EN 60325:2004 (modified)
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CLC IEC/TR 62461:2019 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:

www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050 series International Electrotechnical - -
Vocabulary General Index
ISO/IEC Guide 98-3 2008 Uncertainty of measurement - Part 3: - -
Guide to the expression of uncertainty in
measurement (GUM:1995)
ISO/IEC Guide 98-3 2008 Uncertainty of measurement – Part 3: - -
Supplement 1 Guide to the expression of uncertainty in
measurement (GUM:1995) -
Supplement 1: Propagation of
distributions using a Monte Carlo
method
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SIST-TP CLC IEC/TR 62461:2019
IEC TR 62461
Edition 2.0 2015-01
TECHNICAL
REPORT
colour
inside
Radiation protection instrumentation – Determination of uncertainty in
measurement
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.280 ISBN 978-2-8322-2216-4

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
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SIST-TP CLC IEC/TR 62461:2019
– 2 – IEC TR 62461:2015 © IEC 2015
CONTENTS

FOREWORD ........................................................................................................................... 5

INTRODUCTION ..................................................................................................................... 7

1 Scope .............................................................................................................................. 8

2 Normative references ...................................................................................................... 8

3 Terms and definitions ...................................................................................................... 9

4 List of symbols .............................................................................................................. 12

5 The GUM and the GUM S1 concept ............................................................................... 14

5.1 General concept of uncertainty determination ....................................................... 14

5.1.1 Overview in four steps ................................................................................... 14

5.1.2 Summary of the analytical method for steps 3 and 4 ...................................... 15

5.1.3 Summary of the Monte Carlo method for steps 3 and 4 .................................. 15

5.1.4 Which method to use: Analytical or Monte Carlo? .......................................... 16

5.2 Example of a model function ................................................................................. 16

5.3 Collection of data and existing knowledge for the example .................................... 18

5.3.1 General ......................................................................................................... 18

5.3.2 Calibration factor for the example .................................................................. 19

5.3.3 Zero reading for the example ......................................................................... 20

5.3.4 Reading for the example ................................................................................ 21

5.3.5 Relative response or correction factor for the example .................................. 21

5.3.6 Comparison of probability density distributions for input quantities ................ 23

5.4 Calculation of the result of a measurement and its standard uncertainty

(uncertainty budget) .............................................................................................. 25

5.4.1 General ......................................................................................................... 25

5.4.2 Analytical method .......................................................................................... 25

5.4.3 Monte Carlo method ...................................................................................... 26

5.4.4 Uncertainty budgets ....................................................................................... 26

5.5 Statement of the measurement result and its expanded uncertainty ...................... 27

5.5.1 General ......................................................................................................... 27

5.5.2 Analytical method .......................................................................................... 28

5.5.3 Monte Carlo method ...................................................................................... 28

5.5.4 Representation of the output distribution function in a simple form

(Monte Carlo method) .................................................................................... 31

6 Results below the decision threshold of the measuring device ....................................... 31

7 Overview of the annexes ............................................................................................... 32

Annex A (informative) Example of an uncertainty analysis for a measurement with an

electronic ambient dose equivalent rate meter according to IEC 60846-1:2009 ..................... 33

A.1 General ................................................................................................................. 33

A.2 Model function ...................................................................................................... 33

A.3 Calculation of the complete result of the measurement (measured value,
probability density distribution, associated standard uncertainty, and the

coverage interval) ................................................................................................. 34

A.3.1 General ......................................................................................................... 34

A.3.2 Low level of consideration of measuring conditions ........................................ 35

A.3.3 High level of consideration of measuring conditions ....................................... 37

Annex B (informative) Example of an uncertainty analysis for a measurement with a

passive integrating dosimetry system according to IEC 62387:2012 ...................................... 40

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B.1 General ................................................................................................................. 40

B.2 Model function ...................................................................................................... 40

B.3 Calculation of the complete result of the measurement (measured value,
probability density distribution, associated standard uncertainty, and the

coverage interval) ................................................................................................. 41

B.3.1 General ......................................................................................................... 41

B.3.2 Low level of consideration of workplace conditions ........................................ 41

B.3.3 High level of consideration of workplace conditions ....................................... 43

Annex C (informative) Example of an uncertainty analysis for a measurement with an

electronic direct reading neutron ambient dose equivalent meter according to

IEC 61005:2003 .................................................................................................................... 46

C.1 General ................................................................................................................. 46

C.2 Model function ...................................................................................................... 46

C.3 Calculation of the complete result of the measurement (measured value,
probability density distribution, associated standard uncertainty, and the

coverage interval) ................................................................................................. 47

C.3.1 General ......................................................................................................... 47

C.3.2 Analytical method .......................................................................................... 47

C.3.3 Monte Carlo method ...................................................................................... 48

C.3.4 Comparison of the result of the analytical and the Monte Carlo method ......... 49

Annex D (informative) Example of an uncertainty analysis for a calibration of radon

activity monitor according to the IEC 61577 series ................................................................ 51

D.1 General ................................................................................................................. 51

D.2 Model function ...................................................................................................... 51

D.3 Calculation of the complete result of the measurement (measured value,
probability density distribution, associated standard uncertainty, and the

coverage interval) ................................................................................................. 51

Annex E (informative) Example of an uncertainty analysis for a measurement of

surface emission rate with a contamination meter according to IEC 60325:2002 ................... 54

E.1 General ................................................................................................................. 54

E.2 Model function ...................................................................................................... 54

E.3 Calculation of the complete result of the measurement (measured value,
probability density distribution, associated standard uncertainty, and the

coverage interval) ................................................................................................. 54

E.3.1 General ......................................................................................................... 54

E.3.2 Effects of distance ......................................................................................... 55

E.3.3 Contamination non-uniformity ........................................................................ 55

E.3.4 Surface absorption ........................................................................................ 56

E.3.5 Other influence quantities .............................................................................. 56

E.3.6 Uncertainty budget ........................................................................................ 56

Bibliography .......................................................................................................................... 59

Figure 1 – Triangular probability density distribution of possible values n for the

calibration factor N ................................................................................................................ 20

Figure 2 – Rectangular probability density distribution of possible values g for the

zero reading G .................................................................................................................... 21

Figure 3 – Gaussian probability density distribution of possible values g for the

reading G .............................................................................................................................. 21

Figure 4 – Comparison of different probability density distributions of possible values:

rectangular (broken line), triangular (dotted line) and Gaussian (solid line) distribution ......... 24

Figure 5 – Distribution function Q of the measured value ...................................................... 29

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Figure 6 – Probability density distribution (PDF) of the measured value ................................ 30

Figure C.1 – Results of the analytical (red dashed lines) and the Monte Carlo method

(grey histogram and blue dotted and solid lines) for H * (10) ................................................. 50

Figure D.1 – Result of the analytical (red dashed lines) and the Monte Carlo method

(grey histogram and blue dotted lines) for K ........................................................................ 53

Table 1 – Symbols (and abbreviated terms) used in the main text (excluding annexes) ........ 12

Table 2 – Standard uncertainty and method to compute the probability density

distributions shown in Figure 4 .............................................................................................. 24

Table 3 – Example of an uncertainty budget for a measurement with an electronic

dosemeter using the model function M = N K (G – G ) and low level of consideration

of the workplace conditions, see 5.3.5.2 ............................................................................... 27

Table 4 – Example of an uncertainty budget for a measurement with an electronic

dosemeter using the model function M = N K (G – G ) and high level of consideration

of the workplace conditions, see 5.3.5.3 ............................................................................... 27

Table A.1 – Example of an uncertainty budget for a dose rate measurement according

to IEC 60846-1:2009 with an instrument having a logarithmic scale and low level of

consideration of the measuring conditions, see text for details .............................................. 36

Table A.2 – Example of an uncertainty budget for a dose rate measurement according

to IEC 60846-1:2009 with an instrument having a logarithmic scale and high level of

consideration of the measuring conditions, see text for details .............................................. 38

Table B.1 – Example of an uncertainty budget for a photon dose measurement with a

passive dosimetry system according to IEC 62387-1:2007 and low level of

consideration of the workplace conditions, see text for details .............................................. 42

Table B.2 – Example of an uncertainty budget for a photon dose measurement with a

passive dosimetry system according to IEC 62387-1:2007 and high level of

consideration of the measuring conditions, see text for details .............................................. 44

Table C.1 – Example of an uncertainty budget for a neutron dose measurement

according to IEC 61005:2003 using the analytical method..................................................... 48

Table C.2 – Example of an uncertainty budget for a neutron dose rate measurement

according to IEC 61005:2003 using the Monte Carlo method ................................................ 49

Table C.3 – Results of the analytical and the Monte Carlo method ........................................ 50

Table D.1 – List of quantities used in formula (D.1) ............................................................... 51

Table D.2 – List of data available for the input quantities of formula (D.1) ............................. 52

Table D.3 – Example of an uncertainty budget for the calibration of a radon monitor

according to IEC 61577, see text for details .......................................................................... 52

Table E.1 – Example of an uncertainty budget for a surface emission rate

measurement according to IEC 60325:2002, see text for details ........................................... 57

Table E.2 – Example of an uncertainty budget for a surface emission rate

measurement according to IEC 60325:2002 for the determination of the uncertainty at

a measured value of zero ...................................................................................................... 58

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IEC TR 62461:2015 © IEC 2015 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RADIATION PROTECTION INSTRUMENTATION –
DETERMINATION OF UNCERTAINTY IN MEASUREMENT
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

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

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

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

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.

The main task of IEC technical committees is to prepare International Standards. However, a

technical committee may propose the publication of a technical report when it has collected

data of a different kind from that which is normally published as an International Standard, for

example "state of the art".

IEC 62461, which is a technical report, has been prepared by subcommittee 45B: Radiation

protection instrumentation, of IEC technical committee 45: Nuclear instrumentation.

This second edition of IEC TR 62461 cancels and replaces the first edition, published in 2006,

and constitutes a technical revision. The main changes with respect to the previous edition

are as follows:

– add to the analytical method for the determination of uncertainty the Monte Carlo method

for the determination of uncertainty according to supplement 1 of the Guide to the

Expression of uncertainty in measurement (GUM S1), and

– add a very simple method to judge whether a measured result is significantly different from

zero or not based on ISO 11929.
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– 6 – IEC TR 62461:2015 © IEC 2015
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
45B/783/DTR 45B/813/RVD

Full information on the voting for the approval of this technical report can be found in the

report on voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC website 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.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
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IEC TR 62461:2015 © IEC 2015 – 7 –
INTRODUCTION

The ISO/IEC Guide 98-3:2008, Uncertainty of measurement – Part 3: Guide to the expression

of uncertainty in measurement (GUM:1995) as well as its Supplement 1:2008, Propagation of

distributions using a Monte Carlo method (GUM S1), are general guides to assess the

uncertainty in measurement. This Technical Report lays emphasis on their application in the

area of radiation protection and serves as a practical introduction to the GUM and its

supplement 1 (GUM S1).

The process of determining the uncertainty delivers not only a numerical value of the

uncertainty; in addition it produces the best estimate of the quantity to be measured which

may differ from the indication of the instrument. Thus, it can also improve the result of the

measurement by using information beyond the indicated value of the instrument, e.g. the

energy dependence of the instrument.
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RADIATION PROTECTION INSTRUMENTATION –
DETERMINATION OF UNCERTAINTY IN MEASUREMENT
1 Scope

This Technical Report gives guidelines for the application of the uncertainty analysis accord-

ing to ISO/IEC Guide 98-3:2008 (GUM describing an analytical method for the uncertainty

determination) and its Supplement 1:2008 (GUM S1 describing a Monte Carlo method for the

uncertainty determination) for measurements covered by standards of IEC Subcommittee 45B.

It does not include the uncertainty associated with the concept of the measuring quantity,

e. g., the difference between H (10) on the ISO water slab phantom and on the person.

This Technical Report explains the principles of the ISO/IEC Guide 98-3:2008 (GUM),its

Supplement 1:2008 (GUM S1) and the special considerations necessary for radiation

protection at an example taken from individual dosimetry of external radiation. In the

informative annexes, several examples are given for the application on instruments, for which

SC 45B has developed standards.

This Technical Report is supposed to assist the understanding of the ISO/IEC Guide 98-

3:2008 (GUM), its Supplement 1: 2008 (GUM S1), and other papers on uncertainty analysis. It

cannot replace these papers nor can it provide the background and justification of the

arguments leading to the concept of the ISO/IEC Guide 98-3:2008 (GUM) and its Supplement

1:2008 (GUM S1).

Finally, this Technical Report gives a very simple method to judge whether a measured result

is significantly different from zero or not based on ISO 11929.

For better readability the correct terms are not always used throughout this technical report.

For example, instead of “random variables of a quantity” only the “quantity” itself is stated.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60050 (all parts): International Electrotechnical Vocabulary (available at
http://www.electropedia.org)

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

uncertainty in measurement (GUM:1995)

ISO/IEC Guide 98-3, Supplement 1:2008, Uncertainty of measurement – Part 3: Guide to the

expression of uncertainty in measurement (GUM:1995) – Propagation of distributions using a

Monte Carlo method
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IEC TR 62461:2015 © IEC 2015 – 9 –
3 Terms and definitions
For the purposes of this document, the technical terms of IEC 60050-151 [1], and
IEC 60050-311 [2] as well as the following defin
...

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