IMPROVED ENERGY RESOLUTION OF MERCURIC IODIDE DETECTORS BY NON-CONTACT POLISHING (NCP) PROCESSING AND SCANNING PHOTOVOLTAGE (SPV) EVALUATION

THE NEW COMPOUND SEMICONDUCTOR MATERIAL, MERCURIC IODIDE (HGI2), OFFERS THE POTENTIAL FOR ROOM TEMPERATURE, HIGH STOPPING POWER DETECTORS OF PENETRATING RADIATION. THIS POTENTIAL HAS NOT YET BEEN REALIZED OWING TO THE DIFFICULTIES IN CONSISTENTLY PRODUCING HGI2 STATING MATERIAL FREE FROM BULK AND SURFACE DEFECTS AND INHOMOGENEITIES. THIS PROGRAM WILL IMPROVE ENERGY RESOLUTION AND RESPONSE UNIFORMITY BY ACHIEVING DAMAGE-FREE HGI2 SURFACES USING A NCP TECHNIQUE TO REMOVE SUBSURFACE DAMAGE AND A NON-DESTRUCTIVE SPV TECHNIQUE TO MONITOR THE NCP PROCESS. PHASE I IS TO DEMONSTRATE EXPERIMENTALLY A A DOUBLE-SIDED NCP PROCESS FOR HGI2 CRYSTALS AND TO CORRELATE IMPROVEMENTS OF THE NCP SURFACES WITH ELECTRICALLY ACTIVE SUBSURFACE DEFECTS BY SPV. TO DEMONSTRATE THAT NCP SURFACE PREPARATION MONITORED BY SPV PRODUCES MATERIAL SUITABLE FOR HIGH RESOLUTION HGI2 DETECTORS, TEST DEVICES WILL BE FABRICATED AND EVALUATED. THIS WILL INCLUDE MEASURING LEAKAGE CURRENT, TRANSPORT PROPERTIES, AND RESPONSE UNIFORMITY.