Arrays of position-sensitive Frisch-grid CdZnTe detectors for gamma ray imaging

Abstract

We report on the results from testing CdZnTe (CZT) position-sensitive virtual Frisch-grid (VFG) detectors and a prototype of a 16x16 detector array proposed for a high-energy gamma ray imaging space telescope. Previously, we evaluated the spectroscopic performance of these detectors. Here, we present results from our detector performance studies with an emphasis on position resolution. We employed digital waveform capturing and analog ASIC based approaches to read out the signals from the detectors and evaluate their spectral- and spatial-resolution. The VFG arrays allow for the flexibility to scale-up the dimensions of the detectors for the desired efficiency, while the position information allows for correcting the detectors’ response non-uniformities caused by crystal defects and device geometry, thereby reducing the instrument cost and making them more feasible for emerging applications in gamma-ray astronomy, nonproliferation, portal screening and nuclear safeguards, where large