Single pulse data collection with an X-ray chopper at in situ room temperature Laue crystallography beamline BL03HB

in situ room temperature Laue crystallography has gained increasing attention. This method is suitable for timeresolved Laue crystallography experiments to get crystal structure with only several single-frame data collections. To improve the diffraction efficiency of protein crystals at room temperature, a simple X-ray chopper combined with a fast shutter has been successfully developed and tested at in situ room temperature Laue crystallography beamline BL03HB of the Shanghai Synchrotron Radiation Facility (SSRF). This chopper is built with two aluminum blades. There are two windows on both blades, as well as an internal lead block. The width of windows for transmission of beam can be flexibly adjusted by a steel block coated with lead. The chopping frequency is controlled independently. The device allows chopping frequencies ranging from 0 to 10 Hz, and exposure times down to 100 mu s can be obtained for our Laue diffraction experiment with the combination of a fast shutter. Moreover, a single pulse data collection strategy has been developed at BL03HB. The performance of our single pulse data collection method with the designed chopper for the improvement of data quality has been analyzed. Results show that the quality of diffraction data obtained from the single pulse data collection method is significantly improved, and the developed chopper is very suitable for room temperature Laue crystallography experiments at the synchrotron beamline with super bending magnet as light source.