Performance improvement of CdZnTe detectors using modified two-terminal electrode geometry

Recently, much has appeared in the literature concerning methods to improve the resolution and photopeak efficiency of CdZnTe radiation detectors operating at or around ambient temperature. These methods generally involve either the use of modified electrode structures (e.g. coplanar grids, three-terminal devices) or pulse processing techniques, both of which add complexity, and hence cost, to the production and operation of such devices. In this paper, we will report on results obtained with a simpler, modified two-terminal device. The detector structure combines a planar anode with an extended surface cathode, and relies on a standard, single channel preamplifier/shaping amplifier system. The results obtained demonstrate that the charge collection efficiency of the device, as shown by the Peak-to-Valley (PN) ratio, is significantly improved when compared to the standard planar geometry, especially at higher (>200 keV) photon energies.