NEW GAMMA-RAY DETECTOR STRUCTURES FOR ELECTRON ONLY CHARGE-CARRIER COLLECTION UTILIZING HIGH-Z COMPOUND SEMICONDUCTORS

High-Z compound semiconductors such as HgI2, CdTe, Cd1-xZnxTe and othe rs offer the possibility of high efficiency gamma-detectors at room te mperature. However, with traditional detector structures, energy resol ution for high energies is practically always limited by poor hole col lection characteristics. New detector structures have been developed w hich attempt to minimize the effects of the poor hole collection, so t hat essentially only the electrons contribute to the signal pulse form ation. One new structure, introduced for the first time, is a lateral drift structure for high-Z compound semiconductor detectors. Energy re solutions of < 3% FWHM at 122 keV and < 1% FWHM at 662 keV were obtain ed for a 2 mm thick drift detector.