Effect of front, lateral and back dead layer thicknesses of a HPGe detector on full energy peak efficiency

As well known, High Purity Germanium (HPGe) detectors have a wide range of applications in every area where radiation detection and measurements are involved. One of the most important parameters in this respect is the determination of the full energy peak (FEP) efficiency. There are certain parameters affecting the so-called FEP efficiency. Perhaps the most important one is the thickness of dead layers of the crystal itself. In the current study, we investigated the effects of the thickness of front, lateral and back dead layer thicknesses of the detector crystal on the FEP efficiencies for the energy range 30 keV–5 MeV using EGS4 Monte Carlo simulation package. It was shown that the change in the thickness of the front dead layer has significant effect on the efficiency values for the energy interval 30–400 keV. The change in the thickness of the lateral and back dead layer was shown to have significant effects on the efficiencies for the energy intervals 2–3 MeV and 3–5 MeV, respectively. The results were checked using GEANT4 and a good agreement was observed.