Simulation of CdZnTe gamma-ray spectrometer response

A model of a semiconductor gamma-ray planar detector is presented. The model takes into account the physical phenomena involved in the detection process, namely the gamma-rayʹs interaction with the crystal, the physics of the semiconductorʹs charge collection and the electric field distribution. Its outputs are conventional pulse-height spectra and biparametric (rise time versus pulse height) spectra. Some of the modelʹs capabilities are demonstrated by comparison with spectra obtained for CdZnTe detectors. The comparison between simulated and experimental pulse-height spectra shows a good agreement when the measured electric field profile is used in the simulation. (Electric field is measured via the Pockels effect). A better modeling of the electronics will improve the current quantitative agreement between model and experiment for biparametric spectra.