Acquisition of X-Ray Microanalysis System and Related Specimen Preparation Instrumentation for Electron Microscopy

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ABSTRACT The Biological Sciences Electron Microscope Laboratory is a teaching and research facility in the Department of Biological Sciences at the University of Wisconsin-Milwaukee (UWM). Currently, the electron microscopes in this facility are being used by students and staff in Biological Sciences, Physics, and the Materials, Mechanical and Civil Engineering departments as well as the Center for Great Lakes Studies and the Laboratory for Surface Studies. Researchers in each of these groups have expressed a need for quantitative and qualitative elemental analysis in conjunction with the structural studies currently being conducted. The Biological Sciences Electron Microscopy (BSEM) Laboratory and the Laboratory for Surface Studies (LSS) at the University of Wisconsin- Milwaukee (UWM) are requesting a system of instruments to upgrade the existing electron microscopes in order to meet this need. This instrumentation falls into 3 equipment groupings: analytical, biological specimen preparation and materials specimen preparation. The analytical needs of the researchers will be met through the acquisition of energy dispersive x-ray spectrometers (EDS) for the existing scanning electron microscope (SEM) and transmissions electron microscope (TEM) both of which are located in the BSEM lab. The preparation of biological specimens for elemental analysis is not compatible with conventional chemical fixation, but requires specialized techniques and instrumentation. Therefore, we are requesting cryogenic equipment for processing biological samples for elemental analysis for both scanning and transmission electron microscopy. Finally, for inorganic materials, specialized equipment is needed for the preparation of plan-view and cross-sectional specimens to allow the imaging, diffraction and elemental analysis of surfaces, interfaces and small particles in TEM. The requested equipment will complement the existing instrumentation for SEM materials pr eparation. This system of instruments will be used as an integral part of the research and graduate training programs at UWM. The requested instrumentation will open up new possibilities for research in the biological sciences as well as in materials and engineering research benefiting both ongoing projects and future planned research. Cryofixation combined with elemental mapping will enable researchers in the department of Biological Sciences and the Center for Great Lakes Studies to gain a better understanding of the mechanisms and impact of prokaryotic and eukaryotic organisms in biogeochemical cycling in aquatic environments. In addition, the cryo-preparation instrumentation will greatly enhance the capacity for immunolocalization studies. The cutting and thinning equipment requested for materials specimen processing is required for TEM analysis of brittle and ductile materials. This instrumentation will be used for the preparation of thin cross-sectional and plane-view specimens for elemental analysis and imaging with the existing TEM; it will also be required for the preparation of specimens for an atomic resolution 200kV field emission TEM, for which separate funding is being sought (NSF/DMR 9406752; the Instrumentation for Materials Research Program). Finally, the cutting and polishing tools will aid in the preparation of suitable flat surfaces for elemental analysis of bulk specimens in the SEM.