Carrier-trapping-based imaging evaluation model and experiment of pixellated CdZnTe detector

A flexible induced charge model of CdZnTe pixellated detector is presented. This model takes into account the charge trapping effect in the detection process. The distribution of the trapped carriers in CdZnTe crystal is derived based on the continuity equations. In consequence, an evaluation model based on the presampling modulation transfer function (presampling MTF) is obtained. As shown through the numerical simulation, the detector imaging quality decreases obviously with the increase in incident photon energy. When the electron- and hole-mobility lifetime products are 0.510-3 to 5.010-3 cm2/V and 2.010-5 to 7.510-5 cm2/V, respectively, the model signal is almost due to the electron