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 others offer the possibility of high efficiency gamma-detectors at room temperature. However, with traditional detector structures, energy resolution for high energies is practically always limited by poor hole collection characteristics. New detector structures have been developed which attempt to minimize the effects of the poor hole collection, so that essentially only the electrons contribute to the signal pulse formation. One new structure, introduced for the first time, is a lateral drift structure for high-Z compound semiconductor detectors. Energy resolutions of <3% FWHM at 122 keV and <1% FWHM at 662 keV were obtained for a 2 mm thick drift detector. (orig.)