prEN ISO 11929-1

Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and application - Part 1: Elementary applications (ISO/DIS 11929-1:2025)

The ISO 11929 series 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 has been divided into four parts covering elementary applications in this document, advanced applications on the basis of the ISO/IEC Guide 3-1 in ISO 11929-2, applications to unfolding methods in ISO 11929-3, and guidance to the application in ISO 11929-4.
This document covers basic applications of counting measurements frequently used in the field of ionizing radiation metrology. It is restricted to applications for which the uncertainties can be evaluated on the basis of the ISO/IEC Guide 98-3 (JCGM 2008). In Annex A, the special case of repeated counting measurements with random influences is covered, while measurements with linear analogous ratemeters are covered in Annex B.
ISO 11929-2 extends the former ISO 11929:2010 to the evaluation of measurement uncertainties according to the ISO/IEC Guide 98-3-1. ISO 11929-2 also presents some explanatory notes regarding general aspects of counting measurements and on Bayesian statistics in measurements.
ISO 11929-3 deals with the evaluation of measurements using unfolding methods and counting spectrometric multi-channel measurements if evaluated by unfolding methods, in particular, for alpha- and gamma‑spectrometric measurements. Further, it provides some advice on how to deal with correlations and covariances.
ISO 11929-4 gives guidance to the application of the ISO 11929 series, summarizes shortly the general procedure and then presents a wide range of numerical examples. Information on the statistical roots of ISO 11929 and on its current development may be found elsewhere[33][34].
The ISO 11929 series also applies analogously to other measurements of any kind especially if a similar model of the evaluation is involved. Further practical examples can be found, for example, in ISO 18589[1], ISO 9696[2], ISO 9697[3], ISO 9698[4], ISO 10703[5], ISO 7503[6], ISO 28218[7], and ISO 11665[8].
NOTE A code system, named UncertRadio, is available for calculations according to ISO 11929-1 to ISO 11929-3. UncertRadio[31][32] can be downloaded for free from https://www.thuenen.de/de/fi/arbeitsbereiche/meeresumwelt/leitstelle-umweltradioaktivitaet-in-fisch/uncertradio/. The download contains a setup installation file which copies all files and folders into a folder specified by the user. After installation one has to add information to the PATH of Windows as indicated by a pop‑up window during installation. English language can be chosen and extensive "help" information is available.

Bestimmung der charakteristischen Grenzen (Erkennungsgrenze, Nachweisgrenze und Grenzen des Überdeckungsintervalls) bei Messungen ionisierender Strahlung - Grundlagen und Anwendungen - Teil 1: Elementare Anwendungen (ISO/FDIS 11929-1:2025)

Détermination des limites caractéristiques (seuil de décision, limite de détection et extrémités de l'intervalle élargi) pour mesurages de rayonnements ionisants - Principes fondamentaux et applications - Partie 1: Applications élémentaires (ISO/DIS 11929-1:2025)

La série ISO 11929 spécifie une procédure applicable, dans le domaine de la métrologie des rayonnements ionisants, pour le calcul du «seuil de décision», de la «limite de détection» et des «limites de l'intervalle élargi» pour un mesurande de rayonnement ionisant non négatif, lorsque des mesurages par comptage sont effectués avec une présélection du temps ou du nombre d'impulsions. Le mesurande résulte d'un taux de comptage brut et d'un taux de comptage du bruit de fond ainsi que de grandeurs supplémentaires reposant sur un modèle d'évaluation. En particulier, le mesurande peut être le taux de comptage net défini comme la différence du taux de comptage brut et du taux de comptage du bruit de fond, ou l'activité nette d'un échantillon. Il peut également être influencé par l'étalonnage du système de mesure, par le traitement de l'échantillon et par d'autres facteurs.
L'ISO 11929 a été scindée en quatre parties couvrant les applications élémentaires dans le présent document, les applications avancées reposant sur le Guide ISO/IEC 3-1 dans l'ISO 11929-2, les applications aux méthodes de déconvolution dans l'ISO 11929-3, et les recommandations d'application dans l'ISO 11929-4.
Le présent document couvre les applications de base des mesurages par comptage souvent utilisés dans le domaine de la métrologie des rayonnements ionisants. Il se limite aux applications pour lesquelles il est possible d'évaluer les incertitudes sur la base du Guide ISO/IEC 98-3 (JCGM 2008). L'Annexe A traite du cas particulier des mesurages répétés par comptage avec des influences aléatoires, alors que l'Annexe B couvre les mesurages avec des ictomètres analogiques linéaires.
L'ISO 11929-2 étend l'ancienne ISO 11929:2010 à l'évaluation des incertitudes de mesure conformément au Guide ISO/IEC 98-3-1. L'ISO 11929-2 contient également plusieurs notes explicatives concernant les aspects généraux des mesurages par comptage et les statistiques bayésiennes dans les mesurages.
L'ISO 11929-3 traite de l'évaluation des mesurages en utilisant des méthodes de déconvolution ainsi que de l'évaluation des mesurages multicanaux spectrométriques par comptage en cas d'évaluation par des méthodes de déconvolution, en particulier pour les mesurages spectrométriques alpha et gamma. Elle fournit en outre des conseils pour le traitement avec des corrélations et des covariances.
L'ISO 11929-4 fournit des recommandations pour l'application de la série ISO 11929, résume les grandes lignes de la procédure générale et présente ensuite un large éventail d'exemples numériques. Des informations relatives à l'origine des statistiques de l'ISO 11929 et à son stade de développement actuel peuvent être trouvées dans les Références [33][34].
La série ISO 11929 s'applique également de manière analogue à d'autres mesurages de tout type, notamment si un modèle d'évaluation similaire est concerné. Des exemples pratiques complémentaires peuvent être trouvés, par exemple, dans l'ISO 18589[1], l'ISO 9696[2], l'ISO 9697[3], l'ISO 9698[4], l'ISO 10703[5], l'ISO 7503[6], l'ISO 28218[7] et l'ISO 11665[8].
NOTE Un logiciel, baptisé UncertRadio, est disponible pour les calculs conformes aux ISO 11929-1 à ISO 11929-3. UncertRadio[31][32] peut être téléchargé gratuitement à l'adresse: https://www.thuenen.de/de/fi/arbeitsbereiche/meeresumwelt/leitstelle-umweltradioaktivitaet-in-fisch/uncertradio/. Le logiciel disponible en téléchargement contient un fichier d'installation qui copie tous les fichiers et dossiers à un em

Ugotavljanje karakterističnih mej (odločitveni prag, zaznavanje meje in omejitev intervala pokritja) pri meritvah ionizirnega sevanja - Osnove in uporaba - 1. del: Osnovne aplikacije (ISO/FDIS 11929-1:2025)

General Information

• Status: Not Published
• Publication Date: 03-Mar-2027
• ICS: 17.240 - Radiation measurements
• Technical Committee: CEN/TC 430 - Nuclear energy, nuclear technologies, and radiological protection
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 07-Aug-2025
• Completion Date: 07-Aug-2025
• Ref Project: oSIST prEN ISO 11929-1:2025 - Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and application - Part 1: Elementary applications (ISO/FDIS 11929-1:2025)

Relations

• Revises: EN ISO 11929-1:2021 - Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and application - Part 1: Elementary applications (ISO 11929-1:2019)
• Effective Date: 13-Nov-2024

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-2025
Ugotavljanje karakterističnih mej (odločitveni prag, zaznavanje meje in omejitev
intervala pokritja) pri meritvah ionizirnega sevanja - Osnove in uporaba - 1. del:
Osnovne aplikacije (ISO/FDIS 11929-1:2025)
Determination of the characteristic limits (decision threshold, detection limit and limits of
the coverage interval) for measurements of ionizing radiation - Fundamentals and
application - Part 1: Elementary applications (ISO/FDIS 11929-1:2025)
Bestimmung der charakteristischen Grenzen (Erkennungsgrenze, Nachweisgrenze und
Grenzen des Überdeckungsintervalls) bei Messungen ionisierender Strahlung -
Grundlagen und Anwendungen - Teil 1: Elementare Anwendungen (ISO/FDIS 11929-
1:2025)
Détermination des limites caractéristiques (seuil de décision, limite de détection et
extrémités de l'intervalle élargi) pour mesurages de rayonnements ionisants - Principes
fondamentaux et applications - Partie 1: Applications élémentaires (ISO/FDIS 11929-
1:2025)
Ta slovenski standard je istoveten z: prEN ISO 11929-1
ICS:
17.240 Merjenje sevanja Radiation measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

FINAL DRAFT
International
Standard
ISO/FDIS 11929-1
ISO/TC 85/SC 2
Determination of the characteristic
Secretariat: AFNOR
limits (decision threshold, detection
Voting begins on:
limit and limits of the coverage
interval) for measurements of
Voting terminates on:
ionizing radiation — Fundamentals
and application —
Part 1:
Elementary applications
Détermination des limites caractéristiques (seuil de décision,
limite de détection et extrémités de l'intervalle élargi)
pour mesurages de rayonnements ionisants — Principes
fondamentaux et applications —
Partie 1: Applications élémentaires
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Reference number
ISO/FDIS 11929-1:2025(en) © ISO 2025

FINAL DRAFT
ISO/FDIS 11929-1:2025(en)
International
Standard
ISO/FDIS 11929-1
ISO/TC 85/SC 2
Determination of the characteristic
Secretariat: AFNOR
limits (decision threshold, detection
Voting begins on:
limit and limits of the coverage
interval) for measurements of
Voting terminates on:
ionizing radiation — Fundamentals
and application —
Part 1:
Elementary applications
Détermination des limites caractéristiques (seuil de décision,
limite de détection et extrémités de l'intervalle élargi)
pour mesurages de rayonnements ionisants — Principes
fondamentaux et applications —
Partie 1: Applications élémentaires
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING
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Published in Switzerland Reference number
ISO/FDIS 11929-1:2025(en) © ISO 2025

ii
ISO/FDIS 11929-1:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Quantities and symbols . 6
5 Summary of procedures for evaluating a measurement and calculating the
characteristic limits . 8
5.1 General aspects .8
5.2 Modelling the measurement .9
5.3 General considerations about the applicability of the ISO/IEC Guide 98-3 .9
5.4 Evaluating the input quantities, standard uncertainties and covariances, and the
primary result and its associated standard uncertainty .10
5.5 Evaluating the standard uncertainty as a function of an assumed true value of the
measurand .10
5.6 Calculating the decision threshold and decisions to be made .11
5.7 Calculating the detection limit and assessment of the measurement procedure. 12
5.8 Calculating a coverage interval for the measurand . 12
5.9 Calculating the best estimate of the measurand and its associated standard uncertainty . 13
5.10 Reporting the results .14
6 Fundamentals and evaluation of the measurement .16
6.1 General aspects concerning the measurand .16
6.2 Model of evaluation .16
6.2.1 General model .16
6.2.2 Model in ionizing radiation counting measurements .17
6.3 Evaluation of the primary measurement result .18
6.4 Standard uncertainty associated with the primary measurement result .18
7 Standard uncertainty as a function of an assumed value of the measurand . 19
8 Decision threshold, detection limit and assessments .21
8.1 Specifications .21
8.2 Decision threshold .21
8.3 Detection limit .21
8.4 Assessments . . 22
9 Limits of the coverage interval .23
9.1 General aspects . 23
9.2 The probabilistically symmetric coverage interval . 23
9.3 The shortest coverage interval .24
10 The best estimate and its associated standard uncertainty .24
11 Documentation .25
Annex A (normative) Repeated counting measurements with random influences .27
Annex B (normative) Measurements with ratemeters .32
Annex C (informative) Calculation of the detection limit by iteration .34
Annex D (informative) Calculations with a generalized net count rate .36
Annex E (informative) Distribution function of the standardized normal distribution .39
Bibliography .44

iii
ISO/FDIS 11929-1:2025(en)
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