Three-dimensional signal correction on U1traPeRL CZT detectors

Three-dimensional signal correction on pixellated CdZnTe (CZT) detectors for the UltraPeRL project has been studied using Monte Carlo simulations. Each 2 cm x 2 cm x 0.5 cm CZT detector has 8 x 8 pixellated anodes with a pitch of 2.4 mm. A depth and lateral correction algorithm has been developed in order to estimate both the depth of interaction (DOI) and the lateral position underneath the collecting pixel and therefore correct the signal amplitude. Using only the simple depth correction technique, the energy resolution can reach about 1.2% FWHM at 662 keV for single-pixel gamma-ray interactions. The relative detector-thickness photopeak efficiency is close to 79%. After lateral correction, the relative detector- thickness photopeak efficiency increased to about 88%, while the energy resolution changed little.