Modeling of the induced charge in semiconductor gamma-ray imaging array

Pixelated two-dimensional (2D) arrays of gamma-ray spectrometers based on CdZnTe are of great interest due to the high spatial and energy resolution they provide. In contrast to a single spectrometer, in a 2D array, the field is not uniform and the induced charge is not proportional to the carrier distance from the anodes. For complete performance modelling of such an array, there is a need to calculate the charge induced on the anodes by a single photogenerated charge carrier. In this study, we present a solution based on the Moments Method, which considers the gaps between the anodes, i.e. mixed boundary conditions. This solution is compared with an approximation presented in previous studies. Good agreement is found in the region under an anode, however, in between anodes, more accurate results are achieved using the Moments Method.