ISO 11929-2:2019
Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation — Fundamentals and application — Part 2: Adv

Standard No.

ISO 11929-2:2019

Release Date

2019

Published By

International Organization for Standardization (ISO)

Latest

ISO 11929-2:2019

Scope

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. applications on the basis of the GUM Supplement 1 in this document, applications to unfolding methods 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 of ISO 11929-1:2019 the special case of repeated counting measurements with random influences is covered, while measurements with linear analogous ratemeters are covered in Annex B of ISO 11929-1:2019. This document extends the former ISO 11929:2010 to the evaluation of measurement uncertainties according to the ISO/IEC Guide 98-3-1. It also presents some explanatory notes regarding general aspects of counting measurements and on Bayesian statistics in measurements. 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. 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[30,31].  of the evaluation is involved. Further practical examples can be found, for example, in ISO 18589[1], NOTE A code system, named UncertRadio, is available for calculations according to ISO 119291 to //www​ .thuenen​ .de/en/fi/fields​ -of​ -activity/marine​ -environment/coordination​ -centre​ -of​ -radioactivity/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. . Another tool is the package ‘metRology’[32] which is available for programming in R. It contains the two R functions ‘uncert’ and ‘uncertMC’ which perform the GUM conform uncertainty propagation, either analytically or by the Monte Carlo method, respectively. Covariances/correlations of input quantities are included. Applying these two functions within iterations for decision threshold and the detection limit calculations simplifies the programming effort significantly. It is also possible to implement this part of ISO 11929 in a spreadsheet containing a Monte Carlo add-in or into other commercial mathematics software.

ISO 11929-2:2019 Referenced Document

• ISO 3534-1 Statistics — Vocabulary and symbols — Part 1: General statistical terms and terms used in probability
• ISO 80000-1 Quantities and units - Part 1: General*， 2022-12-06 Update
• ISO/IEC Guide 98-3 Uncertainty of measurement - Guide to the expression of uncertainty in measurement (GUM:1995). Extension to any number of output quantities
• ISO/IEC Guide 99 

ISO 11929-2:2019 history

• 2019 ISO 11929-2:2019 Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation — Fundamentals and application — Part 2: Adv
• 2000 ISO 11929-2:2000 Determination of the detection limit and decision threshold for ionizing radiation measurements - Part 2: Fundamentals and application to counting measurements with the influence of sample treatment