Mini gamma camera based on photon-counting Frisch-grid CdZnTe detectors (Conference Presentation)

Position-sensitive photon-counting virtual Frisch-grid CdZnTe (CZT) detectors provide an economical and robust design for high-efficiency gamma ray cameras for imaging and spectroscopy measurements. They can be used for a variety of applications including gamma-ray astronomy, medical and industrial imaging, environmental cleanup, nuclear safeguards and security. We present the first results from testing a 4x4 array module coupled to a front-end ASIC. Each detector in the array module operates as a mini time-projection chamber. For each gamma-ray event it provides 3D position information with high spatial- and high-spectral resolution. We employ learning algorithms based on extensive detector calibrations to reconstruct positional information and enhance the spectral resolution of the array. Also, the high-position resolution of the array allows for correcting the detectors’ response non-uniformities due to the presence of crystal defects. This allows the developers to use standard-grade (unselected) CZT crystals, while retaining good performance comparable to large-volume pixelated detectors.