Performance of pixelated CZT detectors as a function of pixel and steering grid layout

CdZnTe (CZT) is a wide band-gap II–VI semiconductor and can be used as detector for hard X-rays in astronomical instrumentation and for medical applications. Angular and energy resolutions, as well as detection efficiencies are crucial parameters to characterize the performance of CZT detectors. We studied the detector performance as a function of the geometrical layout of the anode pixel matrix for two 2×2cm2 CZT detectors with thicknesses of 2 mm and 5 mm, respectively. We varied the pixel sizes as well as their relative distances and quantified the energy resolutions and detection efficiencies. We also studied how a steering grid located between pixels affects the energy resolution and detection rate. The results of the study are presented and suggest that a steering grid substantially improves the high-energy performance of thin detectors—whereas thick detectors mainly benefit from larger pixel widths.