The scope of this document concerns that part of nuclear measurement technique in which events (for instance in case of samples) are counted with the help of high resolution gamma spectrometers. In this case a frequency distribution (multichannel spectrum) of measured pulse heights are 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 samples, weighing aspects, the enrichment or instabilities of the measuring device). It is assumend that the distance between two spectrallines is greater than 4 times of full width at half maximum of a peak and that the background near a spectral line may be characterized by a line. Otherwise DIN 25482 part 2 is to be used.