The beamline has two hutches: (i) optics and (ii) experimental (end station). The optics hutch houses several slits systems, beam diagnostics, monochromator and harmonic rejection mirrors. The primary slits define the white beam produced by the undulator source. Since greater beam stability is achieved by placing a cryogenic monochromator before the mirror for low vertically divergent beams, a double crystal monochromator is the first optical element, located 27.4 m from the source, and gives a fixed exit-height beam geometry requiring no movement of the downstream components each time energy is changed. The mirror assembly provides harmonic rejection of problematic high energy photons that can pass through the monochromator particularly at low energies. To cover the required energy range, a double bounce mirror assembly with three stripe surfaces of Si, Rh and Pt element is used. Translation between strips occurs automatically as energy is varied.
The experimental hutch is approximately 4.0 m high 9.7 m long, 5.0 m wide, narrowing to 3.9 m, and houses a large heavy duty 3-circle diffractometer (θ-, 2θ- and δ-circle). Powder specimen in capillary, flat-plate holder or small sample cell can be attached onto a small xyz-table which is mounted on the inner θ-circle. Larger sample cells and stages are mounted on a large moveable sample table. High sample throughput (200 samples, capillary or flat plate) is available via robotic arm.
For high resolution measurement, the large 2θ-circle provides the scanning of positive angles (above the beam) via the use of 5 multiple analysing crystal (MAC) devices, each comprising 9 crystals and detectors. For time-resolved work a wide-angle position sensitive detector (PSD) mounted on the d-circle will be available. The PSD has been specified to perform fast data collection (e.g. 1 powder pattern/ms) with a 90º aperture and an intrinsic angular resolution of 0.01º and is based on Mythen-2 modules.