ISO INTERNATIONAL STANDARD 11929-3 Second edition 2019-02 Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation Fundamentals and application - Part 3: Applications to unfolding methods Détermination des limites caractéristiques (seuil de décision, limite de détection et extrémités de I'intervalle élargi) pour mesurages de rayonnements ionisants Principes fondamentaux et applications Partie3:Applications aux méthodes de déploiement Reference number IS011929-3:2019(E) os1 @ IS0 2019 IS0 11929-3:2019(E) COPYRIGHTPROTECTEDDOCUMENT @ 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: +4122 749 0111 Fax: +41 22 749 09 47 Email: copyright@iso.org Website: www.iso.org Published in Switzerland ii @ IS0 2019 - All rights reserved IS0 11929-3:2019(E) Contents Page Foreword ..iv Introduction ..V 1 Scope. .1 2 Normative references 3 Terms and definitions ..2 4 Quantities and symbols. ..6 5 Evaluation of a measurement using unfolding methods .8 5.1 General aspects. .8 5.2 Models of unfolding and general uncertainty evaluation ..8 5.3 Unfolding as a sub-model .10 5.4 Input quantities and their uncertainties 10 5.5 Parameters of unfolding. .11 5.6 Procedure for unfolding 12 5.7 Modification for Poisson distributed count numbers for unfolding .14 5.8 Evaluation of the primary results and their associated standard uncertainties .15 5.9 Standard uncertainty as a function of an assumed true value of the measurand .16 5.10 Decision threshold, detection limit and assessments .17 5.10.1 Specifications .17 5.10.2 Decision threshold. .18 5.10.3 Detection limit .18 5.10.4 Assessments .18 5.11 Coverage interval and the best estimate and its associated standard uncertainty .18 5.11.1 General aspects 18 5.11.2 The probabilistically symmetric coverage interval 19 5.11.3 The shortest coverage interval. .20 5.12 Documentation. .20 Annex A (informative) Correlations and covariances. ..22 Annex B (informative) Spectrum unfolding in nuclear spectrometric measurement ..25 Bibliography .37 @ IS0 2019 - All rights reserved iii