  The detector must be modeled in the most accurate way when Monte Carlo
simulation method is used for efficiency calculation in gamma-ray spectrometric
studies. This study aims to investigate the effect of the copper contact pin
inside the detector on the efficiency of the HPGe detector for high gamma-ray
energies. Simulated efficiencies were determined for 6 different energies in
the energy range of 1460.8 keV up to 2614.5 keV in point and cylindrical source
geometry. According to the modeling using PHITS Monte Carlo simulation code,
the presence of copper contact pin at high gamma-ray energies caused a decrease
of up to 6% in detector efficiency. It was emphasized that this ignored
parameter should be included in the modeling like all other geometric
parameters used in detector modeling, by showing the effect on the efficiency.
