BS ISO 11929-4:2020 PDF

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. has been divided into four parts covering elementary applications in , advanced applications on the basis of the ISO/IEC Guide 98‑3:2008/Suppl.1 in , applications to unfolding methods in , and guidance to the application in . 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 and in , Annex B, measurements with linear analogous ratemeters are covered. extends to the evaluation of measurement uncertainties according to the ISO/IEC Guide 98‑3:2008/Suppl.1.  also presents some explanatory notes regarding general aspects of counting measurements and Bay...