Characteristics of depth sensing coplanar-grid CdZnTe detectors

The latest depth-sensing coplanar-grid CdZnTe detectors, each has dimensions of 1.5/spl times/1.5/spl times/1 cm/sup 3/ and uses third-generation coplanar-anode design, have been tested. An energy resolution of 2.0% FWHM at 662 keV gamma-ray energy was obtained. Detector performance has been observed experimentally as a function of depth of gamma-ray interaction, and as a function of radial position near the anode surface. The difference between the depth-sensing technique and the relative gain compensation method is discussed. The measured results show the improvement of third-generation anode design, and the advantage of using depth sensing technique for the correction of electron trapping. Material uniformity of CdZnTe crystals manufactured by eV products have been directly observed and compared on two 1.5/spl times/1.5/spl times/1 cm/sup 3/ detectors.