Performance and First Results of the ELETTRA High-Flux Beamline for Small-Angle X-ray Scattering

A new beamline for small-angle X-ray scattering (SAXS) has recently been constructed and is presently under final commissioning at the 2 GeV storage ring ELETTRA. It has been designed specifically for time-resolved studies of non-crystalline and fibrous materials and has been optimized for small-angle scattering measurements. The beamline operates with a SAXS resolution between 10 and about 1400 Å in d spacing (at 8 keV) and has been optimized with respect to high flux at the sample [of the order of 10¹³ photons s^-1 for 8 keV photons (2 GeV, 400 mA)]. Soon it will be possible to perform simultaneously wide-angle diffraction measurements in the d-spacing range 1.2-8 Å (at 8 keV). In order to allow time-resolved (resolution ~1 ms) small-angle scattering measurements, a high-power 57-pole wiggler is used as the beamline source. From its beam, one of three discrete energies, 5.4, 8 and 16 keV, can be selected with a double-crystal monochromator, which contains three pairs of asymmetrically cut plane Si(111) crystals. Downstream, the beam is focused horizontally and vertically by a toroidal mirror. Commissioning tests of this new SAXS beamline showed that all design parameters have been realized.