The scope of this document concerns that part of nuclear measurement technique, in which events are spectrometrically counted, especially when a frequency distribution of measured heights of pulses (multi channel spectrum) is recorded. It takes into account only the statistical character of nuclear events and pulse counting and leaves out of consideration other influences (i.e. measuring geometry the treatment of probes, weighing aspects, the enrichment or instabilities of the measuring device). Influencing poisson-distributions should be replaced by normal-distributions. The purpose of the draft standard is to fix two convenient characteristic values permitting a neutral estimation of detectable results of nuclear radiation measurements by means of spectrometry.