SOFT-ENERGY X-RAY ABSORPTION SPECTROSCOPY BEAM LINE INSTRUMENTATION

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In-hutch instrumentation development continued for the new beam line side station for XAS measurements in the 2-5 keV, BL4-3. In this energy range, x-rays have a very short path length in air and thus the entire beam path is enclosed in a helium atmosphere to enable data collection. The instrumentation developed for this beam line incorporate several features to improve efficiency and ease of use. This includes computer-controlled motorized x-ray slits, a motorized linear motion feed-through, and a computer-controlled shutter to close off the beam between data points (to reduce x-ray induced damage to samples). Oxygen sensors and flowmeters are utilized for monitoring the purity of the helium atmosphere. A LHe cryostream is used for cooling samples to ~50 K.