Stability and characteristics of large CZT coplanar electrode detectors

The single polarity charge sensing method based on coplanar grid electrodes has demonstrated promising results on CZT detectors having volumes of 1 cm³. This work presents the performance of two coplanar grid CZT detectors having dimensions of 1.5 cm×1.5 cm×1.0 cm, among the largest CZT spectrometers that have been reported. About 2.3% and 2.0% FWHM energy resolutions have been obtained on the two detectors at 662 keV gamma-ray energy using basic analog techniques. Improvement can be achieved with depth sensing and digital pulse processing techniques. Additional investigations have studied detector characteristics critical to practical application of these devices. This includes the stability of detector response over a period of several months and the variation of detector performance in environments with high gamma radiation fluxes and at different counting rates