A NOVEL SOLID STASTE ULTRAVIOLET DETECTOR FOR SCINTILLATION READOUT

THE OVERALL PERFORMANCE AND USEFULNESS OF SCINTILLATOR DETECTORS ARE OFTEN LIMITED BY THE EFFICIENCY OF LIGHT COLLECTION BY THE PHOTOSENSOR USED IN CONJUNCTION WITH THEM. MOST SCINTILLATORS THAT EMIT IN THE ULTRAVIOLET REGION (UV) HAVE NOT BEEN FULLY EXPLOITED, CHIEFLY DUE TO THE DIFFICULTY OF MEASURING THE LIGHT OUTPUT IN THAT RANGE. FOR EXAMPLE, BAF2 IS AN ATTRACTIVE SCINTILLATION DETECTOR FOR GAMMA(4)-RAYS, NEUTRONS AND CHARGED PARTICLES BECAUSE OF ITS RADIATION HARDNESS AND FAST TIME RESPONSE. HOWEVER, SINCE ITS FAST LIGHT COMPONENT IS WELL INTO THE UV, ONLY PHOTOMULTIPLIERS TUBES (PMTS) WITH SPECIAL UV TRANSMITTING WINDOWS CAN BE USED. EVEN THE SPECIAL PMTS DO NOT ACHIEVE GOOD PERFORMANCE WITH THESE SCINTILLATORS, AND THEY ARE EXPENSIVE. THE PLAN IS TO DEVELOP A NOVEL SOLID STATE PHOTOSENSOR WHICH WILL HAVE THE EXCEPTIONAL PERFORMANCE, IN THE ULTRAVIOLET REGION OF THE SPECTRUM, THAT WILL TAKE FULL ADVANTAGE OF THE PERFORMANCE OF THESE UV SCINTILLATORS. THIS SENSOR CAN BE FABRICATED IN THE FORM OF HIGH RESISTIVITY, LOW DEILECTRIC CONSTANT FILMS, HAS EXCELLENT RADIATION HARDNESS AND HAS A TUNABLE BANDGAP WHICH OPTIMALLY COVERS THE UV SPECTRUM OF INTEREST. THIS DEVICE WILL BE MADE USING THE TERNARY SEMICONDUCTOR GALLIUM ALUMINUM NITRIDE (GA1-XAX1N). WITH THIS NEW DEVICE, IT SHOULD BE POSSIBLE TO MAKE VERY COMPACT, RUGGED AND EXTREMELY HIGH PERFORMANCE SCINTILLATOR MODULES WHICH COULD FIND WIDE APPLICATIONS IN NUCLEAR INSTRUMENTATION TECHNOLOGY.