PROGRESS IN THE DEVELOPMENT OF LARGE-AREA MODULAR 64X64 CDZNTE IMAGING ARRAYS FOR NUCLEAR-MEDICINE

Previous efforts by our group have demonstrated the potential of hybri d semiconductor detector arrays for use in gamma-ray imaging applicati ons. In this paper, we describe progress in the development of a proto type imaging system consisting of a 64 x 64-pixel CdZnTe detector arra y mated to a multiplexer readout circuit that was custom designed for our nuclear medicine application. The detector array consists of a 0.1 5 cm thick slab of CdZnTe which has a 64x64 array of 380 mu m square p ixel electrodes on one side produced by photolithography; the other si de has a continuous electrode biased at -150 V. Electrical connections between the detector electrodes and corresponding multiplexer bump pa ds are made with indium bump bonds. Although the CdZnTe detector array s characterized in this paper are room-temperature devices, a slight a mount of cooling is necessary to reduce thermally generated dark curre nt in the detectors. Initial tests show that this prototype imager fun ctions well with more than 90% of its pixels operating. The device is an excellent imager; phantom images have a spatial resolution of 1.5 m m, limited by the collimator bore.