EVALUATION OF CDTE DETECTORS WITH SCHOTTKY CONTACTS FOR IMAGING APPLICATIONS

A CdTe detector with Schottky contacts has been tested with special em phasis on the requirements for imaging arrays. The detector can withst and a much higher field strength than conventional CdTe detectors with two ohmic contacts. The higher field strength results in complete cha rge collection, including the holes which are a factor of 10 slower th an the electrons. With moderate cooling to - 20 degrees C and a field strength around 10 kV/cm, the detectors are homogeneous, i.e. the sign al response is independent of the interaction location of the gamma-ra ys. The measured spectra show symmetric full energy peaks with no tail ing to the low-energy side. Polarization effects at room temperature d isappear below 0 degrees C. The detectors are well suited for large im aging arrays in applications such as hard X-ray astrophysics and medic al imaging. (C) 1998 Elsevier Science B.V. All rights reserved.