NEW RARE EARTH ALUMINATE SCINTILLATORS FOR GAMMA-RAY DETECTION

DETECTION OF WEAPONRY AND OTHER HAZARDS IS AN UNFORTUNATE BUT NECESSARY FACTOR IN MODERN TRANSPORTATION ENVIRONMENT. FOR INANIMATE OBJECTS, ONE PARTICULARLY ATTRACTIVE TECHNIQUE IS GAMMARAY DETECTION. IRRADIATION WITH A HIGH-ENERGY SOURCE, SUCH AS A NEUTRON EMITTER, CAUSES ELEMENTS IN THE OBJECT TO EMIT GAMMA RAYS. EACH ELEMENT HAS ITS OWN CHARACTERISTIC RADIATION SIGNATURE, WHICH CAN BE USED TO DETECT SUSPICIOUS QUANTITIES OF THOSE, SUCH AS NITROGEN, ASSOCIATED WITH EXPLOSIVES. THE PROCESS IS SIMPLE, RAPID, NONINVASIVE, AND EFFECTIVE. THE DETECTION PROCESS, HOWEVER, IS ONLY AS EFFECTIVE AS THE RADIATION DETECTOR. SCINTILLATOR MATERIALS FOR GAMMA DETECTIO MUST HAVE HIGH LUMINOSITY, SPEED, AND STOPPING POWER, AND BE ABLE TO OPERATE AT HIGH COUNT RATES UNDER AMBIENT ENVIRONMENTAL CONDITIONS. ALL SCINTILLATORS CURRENTLY AVAILABLE FALL SHORT IN ONE OR MORE OF THESE REQUIREMENTS. WE HAVE DISCOVERED A NEW MATERIAL SYSTEM, BASED ON LUTETIUM ALUMINUM OXIDE, WITH GREAT PROMISE AS A SCINTILLATION DETECTOR. THESE MATERIALS ARE EXPECTED TO HAVE HIGH DETECTION EFFICIENCY AND SPEED, SUPERIOR STOPPING POWER AND DISCRIMINATION, AND BE RELATIVELY EASY TO FABRICATE. WE PROPOSE TO DEFINE THE CONDITIONS FOR FABRICATING THE MATERIALS, EVALUATE THEIR PERFORMANCE, AND LAY THE FOUNDATION FOR FULL-SCALE EXPLOITATION IN THE NEXT PHASE OF THE PROGRAM.