Study on effect of charge sharing events in common-grid pixelated CdZnTe detectors

Due to the steering grid that aids the collection of electrons by the anode pixels, the common-grid pixelated CdZnTe (CZT) detectors have demonstrated better performance than simple pixel detectors. For a detailed analysis of charge sharing and weighting potential cross-talk that occurs near and underneath the gap and energy resolution degradation in common-grid CZT detectors, a detailed detector system modeling package has been developed and a related experiment using a sub-pixel interaction position estimation method has been performed. A 20×20×15 mm³ CZT crystal with an 11×11 common-grid pixel anode array with a 1.72 mm pixel pitch was modeled. The VAS_UM/TAT4 chip is used for ASIC readout. Through system modeling and measurement, the energy resolution degradation and system properties of common-grid CZT detectors has been studied quantitatively.