A CERUSSITE THIN-FILM SCINTILLATOR FOR PARTICLE AND GAMMA DETECTION

LEAD CARBONATE (PBCO3) IS A NEWLY DISCOVERED INORGANIC SCINTILLATOR WHOSE HIGH DENSITY (6.7 G/CM(3)), FAST FLUORESCENT DECAY TIME (5.6 NS), AND LIGHT OUTPUT (TWICE THAT OF BISMUTH GERMANATE AT-40 DEGREES CENTIGRADE) PROMISE BETTER GAMMA-RAY DETECTION EFFICIENCY AND SPEED THAN ANY OTHER INORGANIC MATERIAL. WITH RESPONSE SPEED COMPARABLE TOORGANIC SCINTILLATORS, AND NO LOSS IN ENERGY RESOLUTION OR HIGH STOPPING POWER, PBCO3 COULD REPLACE OR IMPROVE CURRENT METHODS FOR PARTICLE OR GAMMA DETECTION, TRAJECTORY LOCATION, AND MEASUREMENT OF DE/DX OR HADRON CALORIMETRY. THE DISCOVERERS OF PBCO3 HAVE DETERMINED THESE PROPERTIES ONLY FROM CERUSSITE CRYSTALS, THE NATURALLY OCCURRING MINERAL FORM OF PBCO3, BECAUSE METHODS SUITABLE FOR COMMERCIAL SYNTHESIS OF OPTICAL QUALITY CRYSTALS HAVE NOT YET BEEN PROVED. THE OBJECTIVE OF PHASE I IS TO DETERMINE THE FEASIBILITY OF EPITAXIAL GROWTH OF PBCO3 BY ION BEAM ASSISTED DEPOSITION (IBAD), A PROCESS COMMONLY USED FOR ENHANCED ADHESION, FILM DENSIFICATION, RESIDUAL STRESS MODIFICATION, AND GRAIN SIZE MODIFICATION IN ELECTRONIC, OPTOELECTRONIC, AND CERAMIC MATERIALS. SUCH PBCO3 FILMS COULD BE COUPLED TO PHOTOMULTIPLIER TUBES OR AVALANCHE PHOTODIODES TO CREATE COMPACT DETECTORS SUITABLE FOR FAST SPECTROMETRY OR CALORIMETRY. ALTHOUGH IBAD IS NOT SUITABLE FOR LARGE BULK DETECTORS, THIN PBCO3 LAYERS COULD COVER LARGE AREAS OR COULD BE STACKED ON EDGE TO CREATE VERY HIGH SPATIAL RESOLUTION.