Design of new sub-micron protein crystallography beamline at SSRF

Abstract

In Phase-II project at Shanghai Synchrotron Radiation Facility (SSRF), a sub-micron protein crystallography beamline is designed to achieve the focused beam size from 0.5 µm to 20µm. The high harmonics in the spectrum of a cryogenic permanent magnet undulator (CPMU) is adopted to provide X-rays in 5∼25keV. A LN2 cooled double crystal monochromator (DCM) for high energy resolution mode and a double multilayer monochromator (DMM) for high photon flux mode will be used to monochromatize the beam while two-stage focusing optics will be selected to focus the beam. A pair of pre-focusing KB mirrors will generate a secondary source while a second pair of KB mirrors will image the secondary source to a half micron size beam at the sample position. The experimental end station will provide high-resolution native data collection with experimental phasing method (SAD/MAD), in-situ 96-well plate data collection, raster strategy for tiny crystals, and serial crystallography method.