PERMANENT SMALL ANGLE X-RAY SCATTERING STATION ON BEAM LINE 4-2

点击翻译按钮获取中文摘要

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. The SSRL Structural Molecular Biology small-angle x-ray scattering facility BL4-2 is a permanent experimental station dedicated to structural biology studies. It receives the central fan of radiation from the new 20-pole 2-T wiggler beam. The wiggler continues to be operated at a reduced wiggler field (0.66T) to manage thermal load on the optic components until the full SPEAR3 upgrade of the beam line optics is completed. State-of-the-art experimental facilities are provided for structural biology studies on proteins, protein assemblies, virus particles, biological fibers and lipid membranes. The in-hutch instrumentation, featuring a pin-hole geometry small angle scattering camera with an automated distance change mechanism and a built-in ultra-small angle scattering setup, can be configured in many different ways without a large amount of effort to accommodate different data collection modes, including solution scattering, single crystal diffraction, and membrane/fiber diffraction. A portable fiber diffraction setup was built, commissioned and effectively used this year to complement the standard setups. A small amount of facility characterization beam time is used to check and establish satisfactory beam focus in addition to testing and commissioning numerous new hardware and software capabilities, as their development is completed. The positions of hardware components is evaluated and reset every two weeks, including slit blades, hutch tables, and window flanges immediately upstream and downstream of the specimen position. Beam energy calibration is done as a part of the optimization, in order to provide the best possible setup to users, who are increasingly scheduled in a fast turn-around mode.