EN ISO 11929-4:2023
(Main)Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and application - Part 4: Guidelines to applications (ISO 11929-4:2022)
Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and application - Part 4: Guidelines to applications (ISO 11929-4:2022)
This document specifies a procedure, in the field of ionizing radiation metrology, for the calculation of the “decision threshold”, the “detection limit” and the “limits of the coverage interval” for a non negative ionizing radiation measurand when counting measurements with preselection of time or counts are carried out. The measurand results from a gross count rate and a background count rate as well as from further quantities on the basis of a model of the evaluation. In particular, the measurand can be the net count rate as the difference of the gross count rate and the background count rate, or the net activity of a sample. It can also be influenced by calibration of the measuring system, by sample treatment and by other factors.
ISO 11929-4 gives guidance to the application of ISO 11929 (all parts), summarizing shortly the general procedure and then presenting a wide range of numerical examples. The examples cover elementary applications according to ISO 11929-1 and ISO 11929-2.
Bestimmung der charakteristischen Grenzen (Erkennungsgrenze, Nachweisgrenze und Grenzen des Überdeckungsintervalls) bei Messungen ionisierender Strahlung - Grundlagen und Anwendungen - Teil 4: Anwendungsleitfaden (ISO 11929-4:2022)
Dieses Dokument legt im Bereich der Metrologie ionisierender Strahlung ein Verfahren zur Berechnung der „Erkennungsgrenze“, der „Nachweisgrenze“ und der „Grenzen des Überdeckungsintervalls“ für eine nicht negative Messgröße der ionisierenden Strahlung bei Messungen mit Zeit- und Impulsvorwahl fest. Das Mess-ergebnis ergibt sich aus den Ergebnissen von Messungen einer Bruttozählrate und einer Nulleffektzählrate sowie weiteren Größen auf der Grundlage eines Modells der Auswertung. Insbesondere kann die Messgröße die Nettozählrate als Differenz der Bruttozählrate und der Nulleffektzählrate oder die Nettoaktivität einer Probe sein. Sie kann auch durch die Kalibrierung der Messeinrichtung, die Probenbehandlung und andere Faktoren beeinflusst sein.
ISO 11929 ist in vier Teile gegliedert: elementare Anwendungen in ISO 11929-1, fortgeschrittene Anwendun-gen auf der Grundlage von ISO/IEC Guide 98-3:2008/Supplement 1 in ISO 11929-2, Anwendungen auf Entfal-tungsverfahren in ISO 11929-3 und Anleitungen zur Anwendung in ISO 11929-4.
ISO 11929-1 behandelt elementare Anwendungen zählender Messungen, wie sie häufig im Bereich der Met-rologie ionisierender Strahlung vorkommen. Dieser Teil beschränkt sich auf Anwendungen, bei denen die Unsicherheiten auf der Grundlage des ISO/IEC Guide 98-3 (JCGM 2008) ermittelt werden können. In ISO 11929-1:2019, Anhang A, wird der spezielle Fall wiederholter zählender Messungen mit zufälligen Einflüs-sen und in ISO 11929-1:2019, Anhang B, Messungen mit linearen analogen Ratemetern behandelt.
ISO 11929-2 erweitert ISO 11929-1 auf die Auswertung von Messungen, bei denen die Messunsicherheiten nach ISO/IEC Guide 98-3:2008/Supplement 1 ermittelt werden. ISO 11929-2 enthält außerdem Erläuterungen zu allgemeinen Aspekten zählender Messungen und zur Anwendung der Bayes-Statistik auf Messungen.
ISO 11929-3 behandelt die Auswertung von Messungen mit Hilfe von Entfaltungsverfahren und zählende Viel-kanalmessungen, insofern diese mit Entfaltungsmethoden ausgewertet werden, insbesondere alpha- und gam-maspektrometrische Messungen. Außerdem gibt ISO 11929-3 Anleitungen, wie mit Korrelationen und Kovari-anzen zu verfahren ist.
ISO 11929-4 gibt nach einer kurzen Darstellung des Verfahrens mit einer Fülle von numerischen Beispielen Anleitungen zur Anwendung von ISO 11929 (alle Teile). Die Beispiele decken elementare Anwendungen nach ISO 11929-1 und ISO 11929-2 ab.
ISO 11929 (alle Teile) ist auch bei anderen Messungen gleich welcher Art anwendbar, wenn ein vergleichbares Modell der Auswertung angewendet wird. Weitere praktische Beispiele können in anderen internationalen Nor-men gefunden werden, siehe [1] bis [20].[...]
Détermination des limites caractéristiques (seuil de décision, limite de détection et limites de l'intervalle élargi) pour le mesurage des rayonnements ionisants - Principes fondamentaux et applications - Partie 4: Lignes directrices relatives aux applications (ISO 11929-4:2022)
Ugotavljanje karakterističnih mej (odločitveni prag, zaznavanje meje in omejitev intervala pokritja) pri meritvah ionizirnega sevanja - Osnove in uporaba - 4. del: Smernice za uporabo (ISO 11929-4:2022)
Ta dokument določa postopek na področju metrologije za ionizirno sevanje za izračun »odločitvenega praga«, »zaznavanja meje« in »omejitve intervala pokritja« za merjeno veličino ionizirnega sevanja, ki ni negativna, pri štetju meritev s predhodno izbranim časom ali štetji. Merjena veličina izhaja iz bruto hitrosti štetja in hitrosti štetja v ozadju ter iz dodatnih količin na podlagi modela vrednotenja. Merjena veličina je lahko predvsem neto hitrost štetja kot razlika med bruto hitrostjo štetja in hitrostjo štetja v ozadju oziroma neto aktivnost vzorca. Nanjo lahko vplivajo tudi umerjanje merilnega sistema, obdelava vzorca in drugi dejavniki.
Standard ISO 11929-4 podaja navodilo za način uporabe standarda ISO 11929 (vseh delov), pri čemer na kratko povzema splošni postopek in nato predstavlja širok nabor številčnih primerov. Primeri zajemajo elementarne načine uporabe skladno s standardi ISO 11929-1 in ISO 11929-2.
General Information
Overview
EN ISO 11929-4:2023 (ISO 11929-4:2022) provides practical guidance for determining characteristic limits - the decision threshold, detection limit, and limits of the coverage interval - in the field of ionizing radiation metrology. Adopted by CEN, this part of ISO 11929 focuses on counting measurements with preselection of time or counts for a non‑negative measurand (e.g., net count rate or net activity). It summarizes the general ISO 11929 procedure and gives a wide range of numerical examples to support implementation.
Key topics and requirements
- Scope of applicability: Measurements where the measurand derives from gross and background count rates and additional evaluation-model quantities (calibration factors, sample treatment, etc.).
- Characteristic limits: Clear procedural guidance for calculating the decision threshold, detection limit, and limits of the coverage interval for non‑negative measurands.
- Counting measurement variants: Worked examples and rules for:
- Small, moderate and large count uncertainties
- Small count numbers (low-count scenarios)
- Effects of calibration uncertainties (numerator and denominator)
- Background shielding and background effects
- Uncertainty treatment: Guidance on constructing the measurement model, evaluating standard uncertainties, and expressing best estimates consistent with ISO 11929 (all parts).
- Documentation: Recommendations for recording input data, assumptions, and the results of calculations so that decisions (detection vs. non‑detection) are reproducible and auditable.
- Reference to ISO 11929 parts: Practical application examples that relate to ISO 11929-1 and ISO 11929-2.
Practical applications
EN ISO 11929-4:2023 is used to ensure reliable and defensible detection claims in contexts such as:
- Environmental radioactivity monitoring (low-level detection of radionuclides)
- Radiological protection and workplace monitoring
- Radioanalytical laboratories and calibration services
- Nuclear industry measurements and waste characterization
- Medical and nuclear medicine assay validation
- Homeland security and contamination screening
By following these guidelines, practitioners can calculate robust detection limits and decision thresholds, properly account for background count rates, and incorporate calibration and sample‑treatment effects into uncertainty budgets.
Who should use this standard
- Radiation metrologists and laboratory analysts
- Quality managers in accredited testing and calibration laboratories
- Regulatory bodies and auditors overseeing radiological compliance
- Instrument manufacturers and method developers who need to specify detection performance
Related standards
- ISO 11929 (all parts) - foundational methods for characteristic limits in ionizing radiation measurements
- ISO 11929-1, ISO 11929-2 - elementary applications illustrated by EN ISO 11929-4:2023
Keywords: EN ISO 11929-4:2023, ISO 11929-4, decision threshold, detection limit, coverage interval, ionizing radiation metrology, counting measurements, background count rate, net activity, measurement uncertainty.
Frequently Asked Questions
EN ISO 11929-4:2023 is a standard published by the European Committee for Standardization (CEN). Its full title is "Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and application - Part 4: Guidelines to applications (ISO 11929-4:2022)". This standard covers: This document specifies a procedure, in the field of ionizing radiation metrology, for the calculation of the “decision threshold”, the “detection limit” and the “limits of the coverage interval” for a non negative ionizing radiation measurand when counting measurements with preselection of time or counts are carried out. The measurand results from a gross count rate and a background count rate as well as from further quantities on the basis of a model of the evaluation. In particular, the measurand can be the net count rate as the difference of the gross count rate and the background count rate, or the net activity of a sample. It can also be influenced by calibration of the measuring system, by sample treatment and by other factors. ISO 11929-4 gives guidance to the application of ISO 11929 (all parts), summarizing shortly the general procedure and then presenting a wide range of numerical examples. The examples cover elementary applications according to ISO 11929-1 and ISO 11929-2.
This document specifies a procedure, in the field of ionizing radiation metrology, for the calculation of the “decision threshold”, the “detection limit” and the “limits of the coverage interval” for a non negative ionizing radiation measurand when counting measurements with preselection of time or counts are carried out. The measurand results from a gross count rate and a background count rate as well as from further quantities on the basis of a model of the evaluation. In particular, the measurand can be the net count rate as the difference of the gross count rate and the background count rate, or the net activity of a sample. It can also be influenced by calibration of the measuring system, by sample treatment and by other factors. ISO 11929-4 gives guidance to the application of ISO 11929 (all parts), summarizing shortly the general procedure and then presenting a wide range of numerical examples. The examples cover elementary applications according to ISO 11929-1 and ISO 11929-2.
EN ISO 11929-4:2023 is classified under the following ICS (International Classification for Standards) categories: 17.240 - Radiation measurements. The ICS classification helps identify the subject area and facilitates finding related standards.
You can purchase EN ISO 11929-4:2023 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of CEN standards.
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2023
Ugotavljanje karakterističnih mej (odločitveni prag, zaznavanje meje in omejitev
intervala pokritja) pri meritvah ionizirnega sevanja - Osnove in uporaba - 4. del:
Smernice za uporabo (ISO 11929-4:2022)
Determination of the characteristic limits (decision threshold, detection limit and limits of
the coverage interval) for measurements of ionizing radiation - Fundamentals and
application - Part 4: Guidelines to applications (ISO 11929-4:2022)
Détermination des limites caractéristiques (seuil de décision, limite de détection et limites
de l'intervalle élargi) pour le mesurage des rayonnements ionisants - Principes
fondamentaux et applications - Partie 4: Lignes directrices relatives aux applications
(ISO 11929-4:2022)
Ta slovenski standard je istoveten z: EN ISO 11929-4:2023
ICS:
17.240 Merjenje sevanja Radiation measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 11929-4
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2023
EUROPÄISCHE NORM
ICS 17.240
English Version
Determination of the characteristic limits (decision
threshold, detection limit and limits of the coverage
interval) for measurements of ionizing radiation -
Fundamentals and application - Part 4: Guidelines to
applications (ISO 11929-4:2022)
Détermination des limites caractéristiques (seuil de
décision, limite de détection et limites de l'intervalle
élargi) pour le mesurage des rayonnements ionisants -
Principes fondamentaux et applications - Partie 4:
Lignes directrices relatives aux applications (ISO
11929-4:2022)
This European Standard was approved by CEN on 16 July 2023.
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, Türkiye 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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11929-4:2023 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
The text of ISO 11929-4:2022 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 11929-4:2023 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 January 2024, and conflicting national standards shall
be withdrawn at the latest by January 2024.
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.
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, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 11929-4:2022 has been approved by CEN as EN ISO 11929-4:2023 without any
modification.
INTERNATIONAL ISO
STANDARD 11929-4
Third edition
2022-07
Determination of the characteristic
limits (decision threshold, detection
limit and limits of the coverage
interval) for measurements of ionizing
radiation — Fundamentals and
application —
Part 4:
Guidelines to applications
Détermination des limites caractéristiques (seuil de décision, limite
de détection et limites de l'intervalle élargi) pour le mesurage des
rayonnements ionisants — Principes fondamentaux et applications —
Partie 4: Lignes directrices relatives aux applications
Reference number
ISO 11929-4:2022(E)
ISO 11929-4:2022(E)
© ISO 2022
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 11929-4:2022(E)
Contents Page
Foreword .vii
Introduction .viii
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Quantities and symbols . 3
5 Summary of this document .5
5.1 Procedures according to ISO 11929 (all parts) . 5
5.2 Survey on the examples . 5
5.3 General stipulations . 8
6 Counting measurements with small or moderate uncertainties .9
6.1 Definition of the task and general aspects . 9
6.2 Model of evaluation and standard uncertainty . 9
6.3 Available information, input data, and specifications . 9
6.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 . 10
6.4.1 Background effect . 10
6.4.2 Primary result and its associated standard uncertainty . . 10
6.4.3 Standard uncertainty as a function of an assumed true value . 10
6.4.4 Decision threshold . 10
6.4.5 Detection limit . 11
6.4.6 Limits of coverage intervals . 11
6.4.7 The best estimate and its associated standard uncertainty . 11
6.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 . 11
6.6 Assessment and explanations . 13
7 Counting measurement with small count numbers .14
7.1 Definition of the task and general aspects . 14
7.2 Model of evaluation and standard uncertainty . 14
7.3 Available information, input data, and specifications . 14
7.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 .15
7.4.1 Background effect . 15
7.4.2 Primary result and its associated standard uncertainty . .15
7.4.3 Standard uncertainty as a function of an assumed true value . 16
7.4.4 Decision threshold . 16
7.4.5 Detection limit . 16
7.4.6 Limits of coverage intervals . 17
7.4.7 The best estimate and its associated standard uncertainty . 17
7.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 . 17
7.6 Assessment and explanations . 18
7.7 An alternative example of a measurement with small count numbers . 19
7.7.1 General . 19
7.7.2 Background effect . 20
7.7.3 Primary result and its associated standard uncertainty . .20
7.7.4 Standard uncertainty as a function of an assumed true value .20
7.7.5 Decision threshold .20
7.7.6 Detection limit . 21
7.7.7 Limits of coverage intervals . 21
7.7.8 The best estimate and its associated standard uncertainty . 21
7.8 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 .22
7.9 Assessment of the alternative example and explanations. 23
8 Counting measurements with large uncertainties in the numerator of the
calibration factor .23
iii
ISO 11929-4:2022(E)
8.1 Definition of the task and general aspects . 23
8.2 Model of evaluation and standard uncertainty . 24
8.3 Available information, input data, and specifications . 24
8.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 .25
8.4.1 Background effect .25
8.4.2 Primary result and its associated standard uncertainty . .25
8.4.3 Standard uncertainty as a function of an assumed true value .25
8.4.4 Decision threshold . 25
8.4.5 Detection limit . 26
8.4.6 Limits of coverage intervals . 26
8.4.7 The best estimate and its associated standard uncertainty .26
8.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 .26
8.6 Assessment and explanations .28
9 Counting measurements with large uncertainties in the denominator of the
calibration factor .28
9.1 Definition of the task and general aspects .28
9.2 Model of evaluation and standard uncertainty .29
9.3 Available information, input data, and specifications .29
9.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 .30
9.4.1 Background effect . 30
9.4.2 Primary result and its associated standard uncertainty . .30
9.4.3 Standard uncertainty as a function of an assumed true value . 31
9.4.4 Decision threshold . 31
9.4.5 Detection limit . 31
9.4.6 Limits of coverage intervals . 31
9.4.7 The best estimate and its associated standard uncertainty . 32
9.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 . 32
9.6 Assessment and explanations . 33
10 Counting measurements with shielding of the background .34
10.1 Definition of the task and general aspects .34
10.2 Model of evaluation and standard uncertainty .34
10.3 Available information, input data, and specifications .34
10.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 .35
10.4.1 Background effect . 35
10.4.2 Primary result and its associated standard uncertainty . . 35
10.4.3 Standard uncertainty as a function of an assumed true value .35
10.4.4 Decision threshold . 35
10.4.5 Detection limit . 36
10.4.6 Limits of coverage intervals .36
10.4.7 The best estimate and its associated standard uncertainty .36
10.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 .36
10.6 Assessment and explanations .38
11 Counting clearance measurement .38
11.1 Definition of the task and general aspects .38
11.2 Model of evaluation and standard uncertainty .39
11.3 Available information, input data, and specifications .39
11.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 .40
11.4.1 Background effect .40
11.4.2 Primary result and its associated standard uncertainty . .40
11.4.3 Standard uncertainty as a function of an assumed true value .40
11.4.4 Decision threshold . 41
11.4.5 Detection limit . 41
11.4.6 Limits of coverage intervals . 41
11.4.7 The best estimate and its associated standard uncertainty . 42
11.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 . 42
11.6 Assessment and explanations . 43
iv
ISO 11929-4:2022(E)
12 Gamma-spectrometry of Uranium-235 with interference by Radium-226 . 44
12.1 Definition of the task and general aspects .44
12.2 Model of evaluation and standard uncertainty . 45
12.3 Available information, input data, and specifications .46
12.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 . 47
12.4.1 Background effect . 47
12.4.2 Primary result and its associated standard uncertainty . . 47
12.4.3 Standard uncertainty as a function of an assumed true value .48
12.4.4 Decision threshold .49
12.4.5 Detection limit .49
12.4.6 Limits of coverage intervals .49
12.4.7 The best estimate and its associated standard uncertainty .50
12.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 .50
12.6 Assessment and explanations . 51
13 Black box measurements .52
13.1 Definition of the task and general aspects . 52
13.2 Model of evaluation and standard uncertainty . 52
13.3 Available information, input data, and specifications . 53
13.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 .53
13.4.1 Background effect . 53
13.4.2 Primary result and its associated standard uncertainty . .54
13.4.3 Standard uncertainty as a function of an assumed true value .54
13.4.4 Decision threshold .54
13.4.5 Detection limit . 55
13.4.6 Limits of coverage intervals . 55
13.4.7 The best estimate and its associated standard uncertainty .55
13.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 .56
13.6 Assessment and explanations . 57
14 Counting measurements with unknown random influence of sample treatment .57
14.1 Definition of the task and general aspects . 57
14.2 Model of evaluation and standard uncertainty .58
14.3 Available information, input data, and specifications .58
14.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 . 59
14.4.1 Background effect . 59
14.4.2 Primary result and its associated standard uncertainty . . 59
14.4.3 Standard uncertainty as a function of an assumed true value .60
14.4.4 Decision threshold .60
14.4.5 Detection limit . 61
14.4.6 Limits of coverage intervals . 61
14.4.7 The best estimate and its associated standard uncertainty . 61
14.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 . 61
14.6 Assessment and explanations .63
15 Counting measurement with known influence of sample treatment.63
15.1 Definition of the task and general aspects .63
15.2 Model of evaluation and standard uncertainty .64
15.3 Available information, input data, and specifications .65
15.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 .66
15.4.1 Determination of the relative uncertainty of the sample treatment .66
15.4.2 Background effect .66
15.4.3 Primary result and its associated standard uncertainty . .66
15.4.4 Standard uncertainty as a function of an assumed true value . 67
15.4.5 Decision threshold . 67
15.4.6 Detection limit .68
15.4.7 Limits of coverage intervals .68
15.4.8 The best estimate and its associated standard uncertainty .68
15.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 .68
15.6 Assessment and explanations . 70
v
ISO 11929-4:2022(E)
16 Dose measurement using an active personal dosemeter .70
16.1 Definition of the task and general aspects . 70
16.2 Model of evaluation and standard uncertainty . 70
16.3 Available information, input data, and specifications . 71
16.4 Evaluation of the measurement and characteristic limits according to ISO 11929-1 . 71
16.4.1 Background effect . 71
16.4.2 Primary result and its associated standard uncertainty . .72
16.4.3 Standard uncertainty as a function of an assumed true value .72
16.4.4 Decision threshold .72
16.4.5 Detection limit .73
16.4.6 Limits of coverage intervals .73
16.4.7 The best estimate and its associated standard uncertainty .74
16.5 Documentation of the results obtained by ISO 11929-1 and ISO 11929-2 .74
16.6 Assessment and explanations . 75
17 Dose rate measurement using a neutron area monitor .76
17.1 Definition of the task and general aspects . 76
17.2 Model of evaluation and standard uncertainty .77
17.3 Available information, input data, and specifications . 78
17.4 Evaluation of the measurement and characteristic limits .80
17.4.1 Background effect .80
17.4.2 Primary result and its associated standard uncertainty . .80
17.4.3 Standard uncertainty as a function of an assumed true value .80
17.4.4 Decision threshold . 81
17.4.5 Detection limit .82
17.4.6 Limits of coverage intervals .82
17.4.7 The best estimate and its associated standard uncertainty .83
17.5 Documentation of the results .83
17.6 Assessment and explanations .84
Annex A (informative) Determination of a calibration factor .85
Annex B (informative) Calculations according to ISO 11929-2.90
Bibliography .93
vi
ISO 11929-4:2022(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 on 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 the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies,
and radiological protection, Subcommittee SC 2, Radiological protection.
This third edition of ISO 11929-4 cancels and replaces the second edition (ISO 11929-4:2020), of which
it constitutes a minor revision.
The main changes are as follows:
— Editorial changes were done in text and formulae
A list of all parts of ISO 11929 can be found on the ISO website.
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.
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ISO 11929-4:2022(E)
Introduction
Measurement uncertainties and characteristic values, i.e. characteristic limits such as the decision
threshold, the detection limit and limits of the coverage interval for measurements as well as the best
estimate and its associated standard measurement uncertainty, are of importance in metrology, in
general, and for radiological protection, in particular. The quantification of the uncertainty associated
with a measurement result provides a basis for the trust an individual can have in a measurement
result.
NOTE 1 Conformity with regulatory limits, constraints or reference values can only be demonstrated taking
into account and quantifying all sources of uncertainty. Characteristic limits provide – in the end – the basis for
deciding accepting results under uncertainty.
ISO 11929 (all parts) provides characteristic values of a non-negative measurand of ionizing radiation.
It is applicable for a wide range of measuring methods extending beyond measurements of ionizing
radiation.
The limits to be provided according to ISO 11929 (all parts) for specified probabilities of wrong decisions
allow detection possibilities to be assessed for a measurand and for the physical effect quantified by
this measurand as follows:
— the “decision threshold” allows a decision to be made on whether or not the physical effect quantified
by the measurand is present;
— the “detection limit” indicates the smallest true quantity value of the measurand that can still be
detected with the applied measurement procedure; this gives and allows for a decision on whether
or not the measurement procedure satisfies the requirements and is therefore suitable for the
intended measurement purpose;
— the “limits of the coverage interval” enclose, in the case of the physical effect recognized as present,
a coverage interval containing the true quantity value of the measurand with a specified probability.
Hereinafter, the limits mentioned are jointly called “characteristic limits”.
NOTE 2 According to ISO/IEC Guide 99 updated by JCGM 200:2012, the term “coverage interval” is used
here instead of “confidence interval” in order to distinguish the wording of Bayesian terminology from that of
conventional statistics.
All the characteristic values are based on Bayesian statistics and on the ISO/IEC Guide 98-3 as well as
on the ISO/IEC Guide 98-3:2008/Suppl.1 and ISO/IEC Guide 98-3:2008/Suppl.2. As explained in detail in
ISO 11929-2, the characteristic values are mathematically defined by means of moments and quantiles
of probability distributions of the possible measurand values.
Since measurement uncertainty plays an important role in all parts of ISO 11929, the evaluation of
measurements and the treatment of measurement uncertainties are carried out by means of the general
procedures according to the ISO/IEC Guide 98-3 and to the ISO/IEC Guide 98-3:2008/Suppl.1; see also
References [21] to [25]. This enables the strict separation of the evaluation of the measurements,
on the one hand, and the provision and calculation of the characteristic values, on the other hand.
[26] to [28]
ISO 11929 (all parts) makes use of a theory of uncertainty in measurement based on Bayesian
statistics (e.g. References [29] to [36]) in order to allow taking into account also those uncertainties
that cannot be derived from repeated or counting measurements. The latter uncertainties cannot be
handled by frequentist statistics.
Because of developments in metrology concerning measurement uncertainty, laid down in the
ISO/IEC Guide 98-3, ISO 11929:2010 was drawn up on the basis of ISO/IEC Guide 98-3, but using
Bayesian statistics and the Bayesian theory of measurement uncertainty. This theory provides a
Bayesian foundation for the ISO/IEC Guide 98-3. Moreover, ISO 11929:2010 was based on the definitions
[21] [22] [23]
of the characteristic values , the standard proposal , and the introducing article . It unified
and replaced all earlier parts of ISO 11929 and was applicable not only to a large variety of particular
measurements of ionizing radiation but also, in analogy, to other measurement procedures. Some
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ISO 11929-4:2022(E)
explanatory material about the basics of ISO 11929 (all parts), in general, and its application in has been
[42][43]
published elsewhere .
Since the ISO/IEC Guide 98-3:2008/Suppl.1 has been published, the Monte Carlo method has been
used to deal comprehensively with a more general treatment of measurement uncertainty in complex
measurement evaluations. This development provided an incentive for writing a corresponding
[24]
Monte Carlo supplement to ISO 119
...
기사 제목: EN ISO 11929-4:2023 - 이온화 방사선 측정을 위한 특성 한계 (의사 결정 경계, 탐지 한계 및 피복 구간의 한계) 결정 - 기초 및 적용 - 제4부: 응용지침 (ISO 11929-4:2022) 기사 내용: 이 문서는 이온화 방사선 측정 분야에서, 시간 또는 카운트의 사전 선택이 있는 카운트 측정이 수행 될 때 양의 이온화 방사선 measurand의 "의사 결정 경계", "탐지 한계" 및 "피복 구간의 한계" 계산을 위한 절차를 명시합니다. 이 measurand는 총 카운트율, 백그라운드 카운트율 및 평가모델을 기반으로 한 추가적인 양으로부터 나옵니다. 특히 measurand는 총 카운트율과 백그라운드 카운트율의 차이인 순 카운트율 또는 샘플의 순 활동이 될 수 있습니다. 또한, 측정 시스템의 보정, 샘플 처리 및 기타 요소에 의해 영향을 받을 수 있습니다. ISO 11929-4은 ISO 11929 (모든 부분)의 적용에 대한 지침을 제공하며, 일반 절차를 간단히 요약한 다음 다양한 수치적 예제를 제시합니다. 예제는 ISO 11929-1 및 ISO 11929-2에 따른 기본적인 응용을 다룹니다.
記事のタイトル：EN ISO 11929-4：2023 - イオン化放射線の測定における特性限度値（決定限界、検出限界、カバレッジの限界）の決定 - 基礎と応用 - 第4部：応用ガイドライン（ISO 11929-4：2022） 記事の内容：この文書は、イオン化放射線計測の領域で、時間またはカウントの事前選択を行うカウント測定時に非負のイオン化放射線測定成果物の「決定限界」、「検出限界」および「カバレッジの限界」を計算する手順を規定しています。測定成果物は、総計数率、バックグラウンド計数率、および評価モデルに基づく追加の数量によって得られます。特に、測定成果物は、総計数率とバックグラウンド計数率の差であるネット計数率またはサンプルのネット活性度となる場合があります。また、測定システムのキャリブレーション、サンプル処理、およびその他の要素によっても影響を受ける可能性があります。 ISO 11929-4は、ISO 11929（すべての部分）の適用に関するガイドラインを提供し、一般的な手順を簡単に要約し、数値的な例を幅広く示しています。例は、ISO 11929-1とISO 11929-2に基づく基本的な応用をカバーしています。
The article discusses EN ISO 11929-4:2023, which provides guidelines for determining the characteristic limits for measuring ionizing radiation. The document outlines a procedure for calculating the decision threshold, detection limit, and limits of the coverage interval for a non-negative ionizing radiation measurement. The procedure takes into account various factors, such as gross count rate, background count rate, and calibration of the measuring system. ISO 11929-4 offers guidance on the application of ISO 11929 and includes numerical examples to illustrate the procedure.
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