Large area/volume CZT nuclear detectors

Cadmium zinc telluride (CZT) is one of the most promising materials for large-volume gamma-ray spectrometers and imaging arrays. However, because of deficiencies in the high quality material, high-resolution CZT spectrometers are still limited to relatively small dimensions (<2–3 cm3), which make them inefficient at detecting gamma rays. To extend the range of CZT detector applications, an increase in their efficiency is needed without sacrificing the ability to spectrally resolve gamma energies. Achieving this goal requires progress in the growth of large uniform single crystals, reductions in carrier trapping, increases in electrical resistivity, and improved device fabrication procedures. This paper summarizes the current developments in large area/volume CZT detectors and the common constraints on their designs: bulk and surface leakage currents, charge sharing and loss in multi-electrode devices, and charge transport non-uniformities. We also describe recent progress in characterization of CZT materials and devices using new capabilities at Brookhaven National Laboratory. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)