MACCHESS PROGRAM FOR NEW STATION FOR LONG WAVELENGTH CRYSTALLOGRAPHY

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 primary focus of this initiative is to upgrade the CHESS F3 bend-magnet station to be a flexible, double-focused, high-intensity X-ray beamline for long wavelength protein crystallography, including SAD and microcrystal studies. Key to the new capabilities will be a flexible optics system that can accommodate a user-selectable choice of narrow energy-bandpass synthetic multilayer mirrors and focusing elements to optimize particular data collection requirements. Long wavelength, lower energy X-ray capabilities are not commonly available at synchrotron radiation sources today because most beamlines have been designed to deliver high flux. The best high-flux X-ray sources utilize insertion devices, wigglers or undulators, as their X-ray sources. Insertion devices do produce high X-ray intensities but they also produce high heat loads at the same time. To handle these heat loads, beamlines are designed with vacuum windows and graphite filters to dissipate the heat and protect storage ring ultra-high vacuum environments. The windows, however, absorb the long wavelength light and make it virtually impossible to collect high-flux, high signal-to-noise data at wavelengths below 8 keV (1. 5 ¿). Our collaborators have shown tremendous interest in utilizing a powerful beamline at long wavelengths. 1) The Cingolani group (SUNY Upstate Medical University) deals with the mechanisms of