NEW CONCEPTES IN ULTRASENSITIVE NOBLE GAS DETECTION FOR OCEAN SCIENCE APPLICATIONS

COSMOGENIC ARGON-39 IS IDEALLY SUITED FOR STUDYING THE PENETRATION OF GREENHOUSE GASES ACROSS THE THERMOCLINE AND FOR STUDYING DEEP-OCEAN CIRCULATION. THE NEED FOR LARGE SAMPLES AND LONG DECAY-COUNTING TIMES DUE TO ITS LOW CONCENTRATION HAS GREATLY LIMITED THE APPLICATION OF THIS IMPORTANT TRACER. THE OBJECTIVE OF THE PROPOSED RESEARCH IS TO DEVELOP NEW DETECTION TECHNIQUES FOR RARE NOBLE GAS ISOTOPES. IN PHASE I WE WILL EVALUATE TWO DIFFERENT DETECTOR CONCEPTS WHICH COMBINE ELEMENTS OF MASS SPECTROMETRY, CHARGE NEUTRALIZATION, PHOTON BURST, AND RESONANCE IONIZATION SPECTROSCOPY. TRADE-OFFS BETWEEN SELECTIVITY, THROUGHPUT, AND EFFICIENCY WILL BE EXAMINED AND OVERALL PERFORMANCE ESTIMATED FOR EACH CONCEPT. EXPERIMENTS WILL BE CARRIED OUTTO INVESTIGATE BEAM PARAMETERS OF DECELERATED IONS AND TO EVALUATE SELECTIVITY AND BACKGROUND ISSUES OF THE PHOTON BURST TECHNIQUE. RESULTS FROM PHASE I WILL PROVIDE THE BASIS FOR CONSTRUCTION DURING PHASE II OF A PROTOTYPE DETECTOR. THE PROPOSED DETECTOR OFFERS THE POSSIBILITY OF A BREAKTHROUGH IN DETECTION CAPABILITIES FOR MANY ELEMENTS. FOR(39)AR AND (85)KR, THE DETECTOR WILL PROVIDE ISOTOPIC SELECTIVITY >10(17) AND WILL ENABLE MEASUREMENTS ON 20 1 SAMPLES WITH HIGH THROUGHPUT. ADDITIONAL APPLICATIONS INCLUDE GROUNDWATER DATING, POLAR ICE CAP DATING, AND ENVIRONMENTAL STUDIES. A SUBSTANTIAL MARKET SHOULD EXIST BOTH FOR ANALYTICAL SERVICES AND INSTRUMENT SALES BUILT AROUND THE NEW CLASS OF DETECTORS.