Simulation study of charge collection in highly pixilated CdZnTe detector for PET imaging

In this simulation study, we consider a planar CdZnTe detector with pixilated anode as an insert detector for the conventional PET scanner. The anode size is mostly limited by the charge sharing between neighboring pixels. This charge sharing is affected by the following: diffusion of charge particles; original charge particles distribution after the interaction; multiple interactions of gamma rays inside the detector; and electronic crosstalk. To evaluate charge sharing in highly pixilated CdZnTe detectors, we developed the Monte Carlo (MC) simulation tool to guide the experiment design and validate its results. The MC tool includes a gamma tracking module and a signal processing module. The charge distribution after the interaction of gamma with CdZnTe is simulated using EGSnrc code. The simulations were done for CdZnTe detector with cathode-anode distance L=5 mm and anode pixel size W=600 ¿m.