Photo: Daniel Michon, ARTECHNIQUE
BM26B is dedicated to SAXS/WAXS technique. Small-angle and wide-angle patterns can be acquired simultaneously. Two Pilatus photon counting detectors are used to collect the 2D-images. SAXS images are collected using a Pilatus 1M (169mm x 179mm active area). The minimum q-value attainable is about 0.0175 nm-1 (d = 500 nm) with 7m sample-to-detector distance and wavelength 1.54 Å.
WAXS patterns are collected using a 300K linear Pilatus detector ( 254mm x 33.5mm active area). The maximum diffraction angle recordable is about 2Ɵ = 40 °.
To estimate your sample absorption cilck here.
If required, a SAXS/WAXS setup without gap between the two measured patterns is available.
In order to normalize the data, the incoming beam intensity is recorded using an in-air ionization chamber. The sample transmission is measured using a pin-diode integrated in the lead beamstop. These values are usually stored in the header of the edf or hdf5/nexus files.
The beam size can be tuned from few millimeters down to about 300 x 300 micrometers in standard configurations. Post-focusing systems are available in order to achieve a smaller beam size. The experimental hutch contains the SAXS camera with a maximal and minimal camera length of 7 and 1.3 m, respectively. This allows simultaneous SAXS/WAXS measurements with a time resolution down to a few msec/frame. Furthermore a heavy-duty '2+3' type diffractometer (combined '2+2' and 'z-axis') for interface and surface diffraction experiment allowing horizontal and vertical sample orientation is mounted in the same hutch.
The low angle resolution of the SAXS station is dependent on the X-ray wave length and the sample-to-detector distance.
Links and Documentation
For a presentation of the SAXS basic theory, techniques and applications, you can download the book Small Angle X-ray Scattering (O. Glatter and O. Kratky Eds., Academic Press, 1982) from http://physchem.kfunigraz.ac.at/sm/ (Scattering Methods at the Chemistry Department, University of Graz).
For a more biologically oriented introduction one can download Structure Analysis by Small-Angle X-Ray and Neutron Scattering (L. A. Feigin and D. I. Svergun, Plenum Press / Springer, 1987) from http://www.embl-hamburg.de/biosaxs/publications.html
From a practical point of view, you might want to take a look at the Beamline Manuals page. One can find there a short User's survival manual, the full manual of the data acquisition and reduction software for collecting and pre-processing SAXS and/or WAXS data for both static and time-resolved measurements on beamline BM26B, as well as a list of basic Unix commands.
Last but not least, the Data Reduction and Analysis page provides the response of the detector in use, together with links to data reduction and analysis software.
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