This part of ISO 11929 specifies suitable statistical values which allow an assessment of the detection capabilities in high resolution gamma spectrometric ionizing radiation measurements, without the influence of sample treatment [1 to 11]. For this purpose, statistical methods are used to specify the following two statistical values characterizing given probabilities of error.

• The decision threshold, which allows a decision to be made for each measurement with a given probability of error as to whether the registered pulses in a region of interest of the spectrum include a contribution by the sample (e.g. a peak of a gamma line of a nuclide in question).
• The detection limit, which specifies the minimum sample contribution which can be detected with a given probability of error using the measuring procedure in question. This consequently allows a decision to be made to whether a measuring method defined in this part of ISO 11929 satisfies certain requirements and consequently suitable for the given purpose of measurement.