This grant will provides two years partial support for the operation of GeoCAMS, the Earth Science component of the FN tandem van de Graaff accelerator at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry (CAMS) as a facility for isotopic studies in the Earth Sciences. In ten years of successful operation, GeoCAMS has developed and demonstrated capabilities to measure 3H, 7,10Be, 26Al, 36Cl, and 129I at levels found in terrestrial samples and 41Ca at levels found in meteorites. GeoCAMS has measured 15,000 10Be targets, 9400 26Al targets, 9800 36Cl targets, 300 41Ca targets and a lesser number of 3H, 7Be and 129I targets. GeoCAMS, built with DOE and UC funds, has served numerous NSF PIs, including more than twenty during the past year, and has, de facto, come to serve NSF Earth Sciences as a facility for AMS measurements. During this time GeoCAMS has played a key role in education. Twenty-seven Ph.D. students and seven master's students have been trained at GeoCAMS. The large majority of the new surface exposure dating labs set up at U.S. universities during the past few years have been started by young faculty trained at GeoCAMS. In parallel to the facility capability supported by this grant, a wide range of Earth science research in paleoclimate, ice core research, Earth surface processes and atmospheric mixing is carried out by GeoCAMS staff. The goal of this proposal is to make the GeoCAMS facility, which is rated at or near the top of such facilities worldwide, available to the NSF Earth Science community while at the same time continuing to improve the existing performance and to add capabilities for new nuclides, such as in-situ 14C and 53Mn. ***
