Monte Carlo investigation of the charge sharing effects in 3-D position sensitive CdZnTe gamma ray spectrometers

Charge sharing effects in a 3-D position sensitive CdZnTe detector have bee n investigated by Monte Carlo simulations and experimental measurements. Th e charge sharing is mainly caused by the range of electrons, x-ray emission following by photoelectric interactions, and the diffusion of charge carri er electrons during their drift towards the anodes. A simple model has been developed to include the diffusion effect in the Monte Carlo simulation. G ood agreement has been achieved for various irradiation and bias conditions . Based on our model simulations, a I mm. optimal pixel size is recommended for future I cm thick CZT detectors for 662 keV gamma rays.