The use of Monte Carlo calculations in the determination of a Ge detector efficiency curve

Precise measured data and an extensive set of Monte Carlo calculations have been combined to optimize the parameters for a 280 cm3 n-type Ge semiconductor photon detector, with the outcome that the Monte Carlo calculations now provide a very precise detector efficiency curve. The detector position and its length were determined from a set of measurements that included an axial scan. Measurements of the relative efficiencies based on radionuclides with accurately known relative photon emission rates were combined with efficiencies calculated by a Monte Carlo photon and electron transport code to adjust the detector diameter, internal deadlayer thickness, and the effective external deadlayer thickness. Our results show that, in a well-studied situation, it is possible to use Monte Carlo calculations to aid in the determination of a Ge detector's efficiency with an accuracy of about 0.2% from 50 to 1400 keV.