Upgrade of a transmission electron microscope energy dispersive spectroscopy (TEM-EDS) detector for teaching and interdisciplinary research

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This National Science Foundation grant supports the upgrade of an energy dispersive X-ray spectrometry (EDS) and scanning transmission electron microscopy (STEM) detector system for the transmission electron microscope (TEM) in the Dewel Microscopy Facility at Appalachian State University in Boone, NC. The multi-user Dewel Microscopy Facility supports the research and teaching of five departments and is the only electron microscopy facility serving the mountains of western North Carolina. There is no comparable instrumentation (TEM-EDS/STEM) either within the university or in geographical proximity. The TEM at Appalachian State University is used for teaching by multiple departments, and is vital to a variety of research endeavors. It has enabled regional, national, and international collaborations, and attracted and helped retain faculty with active and energetic research programs. TEM-based research will be used not only to recruit students who find independent, high tech laboratory research appealing, but also those who may not feel comfortable with or able to participate in field-based research. Appalachian State University is one of the only providers of science-related outreach activities for a rural, underserved region with an economy that is still classified as “at risk” by the Appalachian Regional Commission. Outreach activities already involving the existing TEM are numerous, and range from hands-on demonstrations to workshops to science festivals. An operational, state-of-the-art detector will allow the facility to increase participation by all students, expand the scope of the outreach activities through the Microscopy Facility, and attract new users from off campus and well as on campus. The newer silicon drift TEM detector (funded by this proposal) will have exponentially faster detection times, better detection limits, will be able to detect light elements, and will not require liquid nitrogen for operation, compared to an TEM-EDS detector (using a Si-Li crystal). This upgrade will allow the university to greatly enhance and expand its research and teaching activities, such as investigating microbial manganese mineral formation in cave and karst environments, exploring the role of mineral-induced selection by microbes, map heavy metal uptake on metal oxide precipitates from acid mine drainage sites, study the microbial ecology of peat bogs, help characterize novel methanogens, map conodont growth, investigate grain boundaries in migmatites, and assist in studies of ore mineral genesis in the central and southern Appalachians.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.