ISO INTERNATIONAL 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 caracteristiques (seuil de décision, limite de détection et limites de I'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 @IS02022 IS0 11929-4:2022(E) COPYRIGHT PROTECTED DOCUMENT IS02022 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may the internet or an intranet, withoutpriorwrittenpermission.Permission can be requested from eitherIso at the addressbelow or Iso's member body in the country of the requester. ISO copyright office CP 401 · Ch. de Blandonnet 8 CH-1214Vernier,Geneva Phone: +41 22 749 01 11 Email: [email protected] Website: www.iso.org PublishedinSwitzerland i @ IS0 2022 - All rights reserved IS0 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 Is0 11929-1 .10 6.4.1 Backgroundeffect 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 IS0 11929-1 and IS0 1i929-2 11 6.6 Assessment and explanations. 13 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 Availableinformation,inputdata,andspecifications 14 7.4 Evaluation of the measurement and characteristic limits according to Is0 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 Decisionthreshold. .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 IS0 11929-1 and IS0 1i929-2 17 7.6 Assessmentandexplanations 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 IS0 11929-1 and IS0 11929-2 22 7.9 Assessmentofthealternativeexampleandexplanations. 23 8 Counting measurements with large uncertainties in the numerator of the calibration factor. 23 @ IS0 2022 - All rights reserved ii IS0 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 Is0 11929-1 .25 8.4.1 Background effect. .25 8.4.2 Primary result and its associated standard uncertainty .25 8.4.3 Standard un