GAMMA-RAY IMAGING AND SPECTROSCOPY SYSTEM USING ROOM-TEMPERATURE SEMICONDUCTOR DETECTOR ELEMENTS

We report on the design, construction, and testing of a gamma-ray imag ing system with spectroscopic capabilities. The imaging system consist s of an orthogonal strip detector made from either HgI2 or CdZnTe crys tals. The detectors utilize an 8x8 orthogonal strip configuration with 64 effective pixels. Both HgI2 or CdZnTe detectors are 1 cm(2) device s with a strip pitch of approximately 1.2 mm (producing pixels of 1.2 mm x x 1.2 mm). The readout electronics consist of parallel channels o f preamplifier, shaping amplifier, discriminators, and peak sensing AD C. The preamplifiers are configured in hybrid technology, and the rest of the electronics are implemented in NIM and CAMAC with control via a Power Macintosh computer. The software used to readout the instrumen t is capable of performing intensity measurements as well as spectrosc opy on all 64 pixels of the device. We report on the performance of th e system imaging gamma-rays in the 20-500 keV energy range and using a pin-hole collimator to form the image.