Background in CdZnTe arrays

Cadmium Zinc Telluride (CdZnTe) arrays show great promise as the prime sens ors for both focusing and non-focusing hard x-ray imaging spectrometers. Ho wever, their sensitivity will be determined to a large degree by the intens ity of the induced background arising from cosmic rays. In December 1995 we investigated this background by irradiating a 10 x 10 x 3 mm(3) CdZnTe cry stal with 199 MeV protons to a fluence of 5 x 10(10) protons cm(-2) at the Indiana University Cyclotron Facility. Beginning less than 3 minutes after the irradiation, and continuing for 15 months, we measured the activity of the CdZnTe with a Ge gamma-ray spectrometer. We have now developed a model to calculate the spallation products and their decay line intensities which can be used to estimate the proton-induced background in CdZnTe arrays in space-based experiments.