Crystal defects and charge collection in CZT x-ray and gamma detectors

Abstract

Cadmium Zinc Telluride (CZT) is one of the most exploited materials for x-ray and gamma ray radiation detection. Nevertheless CZT ingots are still affected by many defects, the most common features are Te inclusions, dislocations and grain boundaries. In this work the results of many investigation techniques are put together and compared in order to have a better understanding of the role of each defect in the degradation of the detector performances. A CZT ingot grown by low pressure Bridgman technique in IMEM Institute, Parma, was analyzed. The material was studied by means of the IR microscopy, for the identification of Te inclusions and then studied with the use of the synchrotron light source (NSLS National Synchrotron Light Source) for the analysis of the crystalline structure and uniformity of the x-ray response.