SEMICONDUCTOR PIXEL DETECTORS FOR GAMMA-RAY IMAGING IN NUCLEAR-MEDICINE

Semiconductor pixel detectors hold great promise for replacing scintil lation cameras in nuclear medicine; improvements in spatial resolution , energy resolution and sensitivity should result. The current status of this subject is briefly reviewed. The fabrication of hybrid, 48 x 4 8 CdZnTe pixel arrays for use in gamma-ray imaging is described. Each detector array is indium-bump bonded to a Hughes 48 x 48 multiplexer c hip; the design is similar to that of an infrared focal-plane array. T he 48 x 48 CdZnTe array is shown to perform well as a gamma-ray imagin g system with 125 mu m spatial resolution (at 60 keV), equivalent to t he pixel spacing. A correction technique for charge spreading between pixels is demonstrated. The implications of macroscopic crystal defect s on array performance are briefly discussed.