New Analytical Approach to Calculate the Co-axial HPGe Detector Efficiency Using Parallelepiped Sources

Abstract

Gamma ray spectrometry using hyper pure germanium (HPGe) detectors has been essential and principal spectroscopy technique in almost all radioactivity measurement laboratories. To calculate the absolute activity, the full-energy peak efficiency of the detector is needed. A new analytical approach is introduced to calculate the full-energy peak efficiency of co-axial HPGe semiconductor detectors, including the source self attenuation correction, the attenuation by the source container and the detector housing materials. The measurements were made using parallelepiped isotropic radiating radioactive sources (152Eu) with different volumes; cover the energy range from 121 keV up to 1408 keV. A remarkable agreement between the measured and the calculated efficiencies was achieved with discrepancies less than 3%.