Verification of efficiency calibrations of two HPGe detectors

In this work, the efficiency calibration of a detector for high resolution gamma ray spectrometry was checked since it was suspected that the one in use was erroneous. The calibration was checked using a certified reference material containing a few gamma emitting radionuclides. The results showed a deviation, in particular at low gamma energies. This is likely due to an increase in the dead layer of the detector since it has been stored at room temperatures for some time. Moreover, due to this fact a new characterization of the detector should be performed since sensitivity calculations show possible deviations in calculated corrections factor for true coincidence summing using the present detector model.