The spatial response of CdZnTe gamma-ray detectors as measured by gamma-ray mapping

We have developed a system to measure the spatial response of cadmium zinc telluride (CZT) radiation detectors. Using this system we have measured the response of several novel detector designs including several variations of the unipolar design. We have observed a wide range of energy resolution and efficiency among the different device designs. Each design has unique strengths and weaknesses which affect the device performance. In addition to design effects on performance, several instances of poor material uniformity degrading the device performance have been observed. In this paper we will discuss the spatial detector response focusing on the effects of the detector design. Where appropriate, we will also discuss the observed effects of material uniformity on device performance.