Monte Carlo modelling of a N-type coaxial high purity germanium detector

This deficiency in the observed detector efficiency is commonly attributed to an underestimation of the thickness of the dead layer on the front area of the detector which is caused by the N+ contact of P-type detectors. Hence, this thickness is often adjusted in the model to match Monte Carlo calculated efficiencies with experimental efficiencies. However, in the case of N-type detectors, this fitting possibility is not availabe since the dead layer at the outer P+ contact is extremely thin (0.3 μm). An alternative explanation for the efficiency discrepancy, especially in the case of N-type detectors, are uncertainties of the physical dimensions of the germanium crystal based on supplied specifications.The purpose of this work is to study the response of a N-type HP Ge detector and to deduce the cause of the efficiency deficit found.