Efficiency simulation of HPGe and Si(Li) detectors in γ- and X-ray spectroscopy

A systematic study of the efficiency simulation of germanium and silicon detectors was performed in the few keV to MeV energy range. Two high-purity germanium (HPGe) detectors and one Si(Li) detectors were simulated by the MCNP and GEANT codes. Critical parameters in the detector geometry were optimized to reproduce the experimental results from several point-like sources. Prediction of the simulation codes for extended sources of high-Z materials were compared with pure, metallic, aged thorium foils. The results indicate that the codes are metrologically valid for extrapolation or interpolation of efficiency experimental data in cases of difficult or impossible experimental determination.