Gamma-ray imaging and spectroscopy system using room-temperature semiconductor detector elements

Abstract

We report on the design, construction, and testing of a gamma-ray imaging system with spectroscopic capabilities. The imaging system consists of an orthogonal strip detector made from either HgI₂ or CdZnTe crystals. The detectors utilize an 8×8 orthogonal strip configuration with 64 effective pixels. Both HgI₂ or CdZnTe detectors are 1 cm² devices with a strip pitch of approximately 1.2 mm (producing pixels of 1.2 mm × 1.2 mm). The readout electronics consist of parallel channels of preamplifier, shaping amplifier, discriminators, and peak sensing ADC. 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 instrument is capable of performing intensity measurements as well as spectroscopy on all 64 pixels of the device. We report on the performance of the system imaging gamma-rays in the 20–500 keV energy range and using a pin-hole collimator to form the image.