Characterization of the H3D ASIC readout system and 6.0 cm 3-D position sensitive CdZnTe detectors

tectors made by eV-Products were characterized using the new H3D Application Specific Integrated Circuits (ASIC) readout system developed by the Instrumentation Division at Brookhaven National Laboratory. The ASIC is capable of reading out energy and timing signals from 121 anode pixels and the planar cathode electrode of one CZT detector simultaneously. The system has a measured electronic noise of 2.2 keV FWHM with a dynamic range from 20 keV to 3.0 MeV. The two detectors achieved energy resolution of 0.48 % FWHM and 0.60 % FWHM, respectively, at 662 keV for single-pixel events from the entire 6.0 cm detec-tion volume at room temperature with an un-collimated Cs source. The average of both detectors were measured to be cm /V. The detection efficiency of the two detectors was evaluated at several different energies up to 1.3 MeV by comparing with simulated data. It was found that the total counts agree well between the measured data and the simulated data over the studied energy range. However, the measured photopeak counts were 10–15 % lower than simulated photopeak counts at high gamma-ray energies. The analysis shows that the loss of pho-topeak efficiency is likely due to the charge loss from peripheral pixels to the boundary of detectors. Index Terms—CdZnTe, position sensitive, 3-D. I