Techniques for Improved High Dose Rate Spectroscopy and Compton Imaging using 3D Pixelated CdZnTe Detectors

High-dose-rate operation of 3D pixelated CdZnTe detectors is complicated by high chance-coincidence rates. Spectra are contaminated by large, chance-coincidence features that reduce photopeak-to-continuum ratios. Compton images, which are formed by true, multiple interaction events, are contaminated by chance-coincidence events. New spectral and Compton imaging techniques, leveraging the intrinsic, 3D nature of pixelated readout, were developed to mitigate the impact of chance-coincidence events at high dose rates. Chance-coincidence mitigation techniques were tested on an H3D, Inc. M400 CdZnTe detector at dose rates exceeding 1 R/h using a ¹³⁷ Cs irradiator. Spectral rejection of chance-coincidence events, as measured by photopeak-to-continuum ratios, was observed by binning events on a by-interaction basis. Compton image quality was improved by preferentially selecting events with small lever arms.