Characterizations and measurements of CZT material: novel techniques and results

The performance of current long-drift-length Cadmium Zinc Telluride (CZT) detectors principally is determined by the material's quality. Hence, the material's limitations must be better understood and potential solutions identified to grow CZT crystals with the required qualities. Our efforts have focused on developing novel techniques and testing methods that will allow us to explore the correlations between the crystal's defects and the detector's properties. Local stoichiometric variations and other local disordering make it very hard to systematically correlate performance and material defects on a macroscopic scale. Therefore, to delineate the factors limiting the energy resolution of CZT detectors, we directed our efforts towards micron-scale material characterization and assessments of the detectors using the National Synchrotron Light Source (NSLS). The NSLS offers us a highly collimated high-intensity X-ray beam that we employed to undertake detector-performance mapping, and to investigate the association between microscopic defects and fluctuations in collected charge. In this paper, we illustrate our techniques and results.