A new small-angle X-ray scattering set-up on the crystallography beamline I711 at MAX-lab

A small-angle X-ray scattering (SAXS) set-up has recently been developed at beamline I711 at the MAX II storage ring in Lund (Sweden). An overview of the required modifications is presented here together with a number of application examples. The accessible q range in a SAXS experiment is 0.009-0.3 angstrom(-1) for the standard set-up but depends on the sample-to-detector distance, detector offset, beamstop size and wavelength.

The SAXS camera has been designed to have a low background and has three collinear slit sets for collimating the incident beam. The standard beam size is about 0.37 mm X 0.37 mm (full width at half-maximum) at the sample position, with a flux of 4 X 10 10 photons s(-1) and lambda = 1.1 angstrom. The vacuum is of the order of 0.05 mbar in the unbroken beam path from the first slits until the exit window in front of the detector.

A large sample chamber with a number of lead-throughs allows different sample environments to be mounted. This station is used for measurements on weakly scattering proteins in solutions and also for colloids, polymers and other nanoscale structures. A special application supported by the beamline is the effort to establish a micro-fluidic sample environment for structural analysis of samples that are only available in limited quantities.

Overall, this work demonstrates how a cost-effective SAXS station can be constructed on a multipurpose beamline.