MATERIALS SCIENCE X04SA

General description and specifications

General beamline specifications

The MS beamline produces a high flux of hard X-rays from a wiggler source. A detailed technical description of the beamline can be downloaded here. The beamline sequentially serves two endstations, described briefly here:

• Powder diffraction (PD) is performed in Experimental Hutch 1 (EH1). PD provides detailed information on the atomic structure of crystalline materials. At the PD station, there are two detector systems - a crystal-analyzer system consisting of 5 detectors, used for the highest resolution data, and a unique "microstrip detector". The second generation microstrip detector, Mythen 2, consists of 30,720 Si-detector elements (50 micron strips, each subtending 4 x 10^-3degrees). The total subtended angle is 120^o. Mythen 2 has a lower intrinsic resolution than the crystal analyzer, but has the enormous advantage that entire diffraction spectra can be acquired in a small fraction of a second, thereby accelerating data acquisition rates by several orders of magnitude. The present maximum frame rate is 5 Hz, but is expected to increase to 10 kHz in the future.

• X-rays and neutrons (x+n) In addition to user operation for powder diffraction alone, it is also possible to apply for beamtime at the powder station as part of a pilot project involving the combined use of x-rays and neutrons to investigate materials structure.

• In-situ surface diffraction (SD) is performed in Experimental Hutch 2 (EH2). The heart of the station is a large 2+3-circle surface diffractometer from Micro-Controle Newport, with two circles for the sample and three for the detector, plus a hexapod for precise alignment of the sample surface relative to the diffractometer axes. The diffractometer can be operated in two modes, either with a vertical, or a horizontal sample surface orientation.
  The detector system is the PILATUS II novel photon-counting 2-D pixel detector, consisting of 486 x 195 pixels, each pixel subtending 0.0088^o x 0.0088^o. It also provides unsurpassed signal-to-noise ratios due to its zero electronic background noise, and has an excellent point spread function. The present maximum frame rate is 200 Hz.
  Typical surface diffraction experiments include recording crystal truncation rods, superstructure rods, reflectivity curves, in-plane diffraction, grazing-incidence small-angle scattering experiments, and time-resolved studies.