The new ALBA diffractometer for microfocus beam macromolecular crystallography experiments at XAIRA beamline

XAIRA, the new microfocus MX beamline at ALBA aims to deliver optimal diffraction images by enclosing the entire end-station in He atmosphere, including the diffractometer and the detector, while keeping the compatibility with standard cryo-crystallography tools and robot. The sub-100 nm SoC diffractometer, based on a unique helium bearing goniometer also compatible with air, has been designed to deliver high quality data from micron sized crystals from fast oscillation and fixed-target MX experiments while allowing a tight sample to detector distance of 70mm. The diffractometer also includes a double on-axis visualization system for sample imaging at sub-micron resolutions, a quick retractile collimator and beamstop assembly, a front- and backlight illumination system and a fast in/out YAG:Ce screen system for beam positioning. Here, the overall system design and performance results are presented.