LEAD IODIDE SEMICONDUCTOR FOR NUCLEAR SENSOR

LEAD IODIDE (PBI2) IS A LITTLE USED COMPOUND SEMICONDUCTOR THE HIGH ATOMIC NUMBERS OF ITS CONSTITUENT ELEMENTS GIVES ITEXTRAORDINARY PHOTOELECTRIC ABSORPTION EFFICIENCY OFOR GAMMAPHOTONS, WHILE ITS 2.5 EV BANDGAP PROMISES PERFORMANCE AT TEMPERATURES UP TO 250 DEGREES C. IT HAS SHOWN SOME PROM- ISE AS A HIGH EFFICIENCY SOLID-STATE DETECTOR, BUT EARLY DEVICES WERE LIMITED BY MATERIAL IMPURITIES AND IMPERFEC- TIONS. RECENTLY NEW PURIFICATION AND CRYS TAL GROWTH TECHNIQUES HAVE BEEN DEVELOPED, LEADING TO MATE- IAL WITH MUCH IMPROVED CRYSTALLOGRAPHIC, MECHANICAL AND OP- TICAL PROPERTIES. WE PROPOSE TO APPLY THESE TECHNIQUES TO THE PROBLEM OF DEVELOPING A NEW HIGH-Z SEMICONDUCTOR DETEC- TOR. IN PHASE I WE WILL PURIFY THE MATERIAL, GROW SEVERAL CRYSTALS AND EVALUATE THEIR ELECTRONIC PROPERTIES. SUCH A DETECTOR WOULD FIND AN ENORMOUS RANGE OF SPECIALIZED APPLICATIONS WHERE THE SMALL SIZE, RELAXED ENVIRONMENTAL CRITERIA AND HIGH EFFICIENCY WOULD ENABLE PREVIOUSLY IMPOSSIBLEMEASUREMENTS, OR WOULD SIGNIFICANTLY SIMPLIFY THE DESIGN OF EXISTING INSTRUMENTS IN MEDICAL DIAGNOSTIC INSTRUMENTATION,INDUSTRIAL CONTROL AND SCIENTIFIC EXPERIMENTS.