Upgrade of Mass Spectrometer

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9612548 Gill This grant provides $20,000 as one-half support of the costs of upgrading their present VG Sector 54 thermal ionization mass spectrometer (TIMS) with a wide aperture retarding potential (WARP) lens and third generation VG Faraday cups to replace their eight existing cups. The WARP lens will greatly increase the abundance sensitivity of this instrument (by two orders of magnitude) allowing measurement of thorium (Th) isotope ratios for petrogenic studies of mid ocean ridge basalts (MORB) without the frequent downtime required for baking the TIMS and greater precision analyses of uranium (U), strontium (Sr), lead (Pb) and Hafnium (Hf) isotopes for improved U/Pb geochronology and isotopic tracer studies of magma genesis. The third generation faraday cups minimize secondary electron loss due to design improvements including increased depth and improved internal coatings and thus provide improved precision and minimal gain drift relative to their existing cups. These improvements will enhance the capabilities of this lab for a wide range of studies including, U-series isotopic studies of oceanic and continental volcanics as petrogenic tracers, Lu/Hf isotopic analyses of deep crustal xenoliths for dating melt extraction events as young as 25 Ma, Sr isotopic analyses of bone and tooth apatite as indicators of the paleodiet and migration behavior of fossil invertebrates, high resolution (100ka) Sr isotope stratigraphy and studies of the biogeochemistry of lead. ***