HIGH ENERGY RESOLUTION CADMIUM-ZINC-TELLURIDE SEMICONDUCTOR RADIATION DETECTORS

THERE IS A NEED FOR IMPROVED, MINIATURIZED RADIATION DETECTORS FOR ON-SITE MEASUREMENTS OF CONTAINERS OF NUCLEAR MATERIAL, PARTICULARLY URANIUM AND PLUTONIUM. DETECTORS CURRENTLY AVAILABLE REQUIRE CRYOGENIC COOLING (HIGH-PURITY GERMANIUM) OR LACK THE ENERGY RESOLUTION NECESSARY TO VERIFY PLUTONIUM ACCURATELY (SODIUM IODIDE). CADMIUM TELLURIDE DETECTORS HAVE BEEN A PROMISING ALTERNATIVE BUT HAVE SUFFERED FROM MATERIALS AND DEVICE PROBLEMS WHICH HAVE PREVENTED THEM FROM REALIZING THEIR POTENTIAL. PHASE I SHOULD DEMONSTRATE A ROOM TEMPERATURE CDZNTE P-I-N RADIATION DETECTOR WITH SENSITIVITY AND ENERGY RESOLUTION THAT IS SUPERIOR TO CURRENT CDTE DETECTOR TECHNOLOGY. THE IMPROVEMENT WOULD RESULT FROM AN IMPROVED MOBILITY-LIFETIME PRODUCT AND HIGHER INTRINSIC RESISTIVITY FOR CDZNTE COMPARED TO CDTE. ADDITIONALLY, THE HISTORIC OHMIC CONTACT PROBLEMS OF CDTE WOULD BE OVERCOME BY GRADING THE COMPOSITION OF THE P AND N CONTACT LAYERS TO ZNTE AND CDTE, RESPECTIVELY. THE ENHANCED PERFORMANCE OF THIS DETECTOR WILL BE VERIFIED BY MEASURING THE GAMMA RAY SENSITIVITY AND ENERGY RESOLUTION OF THE DEVICE USING HIGH ENERGY RADIONUCLIDE SOURCES. DETECTOR STRUCTURE WILL BE OPTIMIZED DURING PHASE II AND PROTOTYPE MINIATURIZED PROBES WILL BE BUILT FOR VERIFICATION OF NUCLEAR MATERIALS.