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
1 Scope
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
has been divided into four parts covering elementary applications in ISO 11929‑1, advanced applications on the basis of the ISO/IEC Guide 98‑3:2008/Suppl.1 in ISO 11929‑2, applications to unfolding methods in ISO 11929‑3, and guidance to the application in ISO 11929‑4.
ISO 11929‑1
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 ISO 11929‑1:2019, Annex A the special case of repeated counting measurements with random influences and in
ISO 11929‑1:2019, Annex B, measurements with linear analogous ratemeters are covered.
ISO 11929‑2
extends ISO 11929‑1 to the evaluation of measurement uncertainties according to the ISO/IEC Guide 98‑3:2008/Suppl.1. ISO 11929‑2 also presents some explan...