SINGLE CRYSTAL FIBERS OF BISMUTH GERMANATE FOR SCINTILLATION DETECTORS

SCINTILLATION DETECTORS HAVE BEEN, AND ARE CONTINUING TO BE,INSTRUMENTAL IN THE DISCOVERY OF NEW FINDINGS IN MANY FIELDSINCLUDING NUCLEAR PHYSICS, HIGH ENERGY PHYSICS, ASTROPHYSICS, SOLID STATE PHYSICS, CHEMISTRY, BIOLOGY, MEDICINE, AND EARTH SCIENCES. THE MOST EFFICIENT SCINTILLATING MATERIALS HAVE BEEN THE INORGANIC CRYSTAL SCINTILLATORS. NAI(TI) HAS BEEN THE MOST WIDELY USED MATERIAL AND HAS LED TO MANY IMPORTANT DISCOVERIES AND APPLICATIONS. HOWEVER, THIS MATERIAL HAS SEVERAL DISADVANTAGES IN THAT IT IS HYGROSCOPIC, HAS A LONG RADIATION LENGTH, AND HAS POOR MECHANICAL PROPERTIES. BISMUTH GERMANATE (BGO) OVERCOMES MOST OF THE SHORTCOMINGS OF NAI(TI) AND HAS A REDUCED "AFTERGLOW" AS WELL. RECENTLY,POLYMER SCINTILLATION FIBERS SHOWED THAT FIBERS CAN SIGNIFICANTLY REDUCE THE SIZE OF SCINTILLATION DETECTOR SYSTEMS AND CAN RESULT IN MUCH GREATER SPATIAL RESOLUTION. PHASE I WILL DEVELOP SINGLE CRYSTAL FIBERS OF BGO USING A LASER-HEATED PEDESTAL GROWTH TECHNIQUE LICENSED FROM STANFORD UNIVERSITY. THESE FIBERS WILL HAVE MUCH GREATER EFFICIENCIES THAN THE DEMONSTRATEDPOLYMER FIBERS AND WILL HAVE EVEN HIGHER RESOLUTION. THIS COULD LEAD TO MUCH SIMPLER AND CHEAPER DETECTION SYSTEMS FOR NUCLEAR AND HIGH ENERGY PHYSICS AND FOR MEDICAL SYSTEMS AS WELL.