COMMISSIONING OF THE INTEGRATED ULTRA SMALL ANGLE X-RAY SCATTERING SETUP

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We have successfully commissioned the newly integrated Bonse-Hart geometry ultra small angle x-ray scattering (USAXS) setup this year. The characterization results were reported in an oral presentation at the annual meeting of the American Crystallographic Association meeting. The USAXS setup delivered the characteristics closely comparable to those we had obtained in previous years with the stand-alone USAXS setup: full-width at 10-4 of the beam peak intensity 220 micro-radians (previously 66); small angle resolution 1 micrometer (previously 4 micrometer). We believe further optimization of optics component alignment will bring these values further closer to previous values. A typical USAXS scan takes several minutes and we have sufficient angular overlap with the pin-hole camera as had been achieved by the stand-alone setup. We are in the process of transferring the USAXS scan control from Super, a VMS-based experiment control program, to Blu-ICE on Linux for improved integration with the pinhole camera setup. We also modified the amplifier electronics of the avalanche photodiode, and this improved the reliability of the USAXS detection system.