Acquisition of a pXRF and refurbishment of used germanium detectors for research and undergraduate research training

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This grant supports the expansion of gamma counting facilities at Oberlin College to improve the throughput of samples used to determine the activity of short-lived fallout radionuclides in river sediment. The grant will be used to acquire a used and fully functional germanium detector, refurbish and upgrade two older used detectors, and acquire supplies to support these new-to-Oberlin instruments. The detectors will be used for projects fingerprinting depth of erosion in response to major storms and changes in human land use. Ongoing projects supported by these detectors include documenting the effects of Hurricane Maria on erosion in Dominica, the effects of wide spread transition to organic agriculture in Cuba, and the effects of deforestation and reforestation projects in China. Oberlin is a liberal arts college with a strong history of undergraduate involvement in research. An average of 7 students per semester and summer will use the detectors. Many of the students who will work with the equipment are likely to be members of groups typically underrepresented in the earth sciences. Thus, the grant includes funding for a faculty member and student each year to attend a conference focused on minority participation in earth science. In addition, the detectors will be used for outreach with K-12 and college students. Modern quantitative geology increasingly relies on chemical measurements to make observations about Earth processes. Schmidt's geomorphology group uses fallout radionuclides (210Pb, 137Cs, 7Be) to fingerprint relative changes in timing and depth of erosion in upstream watersheds in order to understand the effects of land use change and major storms on erosion. This research relies on a germanium detector for gamma counting. Each sample is counted for 24-96 hours on Schmidt's only detector; machine time is a major constriction point for lab throughput. Funds from this project will be used to refurbish two germanium detectors given to Oberlin and acquire a used, but functioning, detector. It will additionally be used to acquire sample preparation and analysis equipment necessary to optimize student training and use of the germanium detectors. The additional germanium detectors will increase throughput of samples in the lab by quadrupling the number of machines counting samples and thus quadruples sample throughput in the lab.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.