Présentation des activités de la ligne SWING de diffusion des rayons X aux petits angles au Synchrotron SOLEIL


SWING is the SAXS / WAXS beamline at SOLEIL, mainly dedicated to biology and soft condensed science. The source is a U20 in-vacuum undulator, thus providing a high intensity beam with small size and low divergence. The Si111 fixed exit double crystal monochromator enables an energy range from 4 to 17 keV, with a flux of 5.1012 photons/s at 12 keV. Two bendable perpendicular mirrors in Kirckpatrick Baez configuration provide a focused beam in the experimental hutch of 400 µm x 70 µm (HWHM). A large motorised table allows for fine positioning of heavy sample environments. The 17 x 17 cm2 AVIEX CCD detector is positioned on a three axes translation stage inside a large vacuum chamber. The sample to detector distance can be remotely changed from 0.5 to 8 m. A user-friendly graphical interface allows for collection and online data reduction. Absolute intensity measurements are routinely achieved using water as reference sample and calibrated monitors.

Dedicated sample environments were developed to provide the scientific communities with optimised experimental conditions. For biologists, an automated solution sampler, including a thermostated capillary cell with online measurement of UV-Vis absorption, permits precise and reproducible measurements of proteins in solution, using as small volumes as a few µl. An HPLC system is also routinely used for online purification. For soft-condensed matter, numerous devices are available: a Linkam 600°C furnace, a thermostated automatic sample changer, a home-made Couette cell and an Anton Paar rheometer for rheology measurements. SWING welcomed its first external users by the end of 2007, and is fully operational since July 2008.

During this talk, experimental examples covering several fields will be presented.