Improved Resolution for 3-D Position Sensitive

Abstract—Two three-dimensional position sensitive CdZnTe gamma-ray spectrometers based on VAS2/TAT2 ASICs were con-structed and fully tested. Each 1.5 1.5 1 cm3 CdZnTe detector employs 11 11 pixelated anodes. Each pixel location provides the interaction’s lateral coordinates, while the cathode/anode signal ratio and the electron drift time are both used to obtain the interaction depth. Data-acquisition and processing software were developed to perform calibration and real-time spectroscopy. An energy resolution of 1.11 % full-width at half-maximum (FWHM) at 662 keV was obtained for single-pixel events from the 120 working pixels of one detector, and an energy resolution of 1.14% FWHM was obtained on the other detector. Significant progress in improving energy resolution for multiple pixel events has been realized. The energy resolutions at 662 keV for two-pixel events and three-pixel events were 1.57 % FWHM and 2.13 % FWHM, respectively. Index Terms—CdZnTe, CZT, gamma-ray spectroscopy, position sensitive, spectrometer, three-dimensional (3-D). I