Cadmium Zinc Telluride Detectors for Imaging of Gamma Rays

Planar arrays of cadmium zinc telluride photodetectors with readout electronic circuitry have been developed for use as hard-x-ray and y-ray image sensors. When a coded, x-and-y-ray-opaque aperture mask is positioned in front of such a sensor, the resulting assembly is an instrument that can be used to observe hard-x-ray and y-ray sources. In operation, the spatial pattern of x and g rays impinging on the sensor is deconvolved from the aperture pattern to obtain an image of the source. With suitable choice of the sensor pixel pitch, coded aperture pattern, and distance of the aperture in front of the detector array, it should be possible to image radiation sources at angular resolutions of 30 arc seconds and finer. In the original intended application, the instrument will be operated in outer space to measure precisely the directions to distant sources of hard-x-ray and g-ray bursts that are of cosmological interest. The instrument can also be used to image hard-x-ray and y-ray-sources in a terrestrial laboratory setting; indeed, a prototype of the instrument has been demonstrated in such a setting.