CALCULATION OF THE EFFICIENCY FOR CYLINDRICAL VOLUME SOURCES IN GAMMA-SPECTROMETRY

A new method has been developed for calculating the full energy peak e fficiency of gamma spectrometry measurement systems. The technique use s the fact that the relationship between total and full energy peak ef ficiency depends on a Ge detector. First, the full energy peak efficie ncy of a closed point source standard with known activities centered a xial at the face of a detector is measured at different energies. This calibration records all the required intrinsic characteristics of the detector; other experimental or theoretical views. are not necessary. All other factors required, i.e., the sum of the path lengths of the photons in the volume source and the detector, the sum of the path len gths of the photons in the detector for the point source, the value of the self-attenuation for the photons in the volume source and the tot al efficiency of the point and volume source, are determined by a rece ntly developed Monte-Carlo-simulation (MCS).