Overview.
SXD, the Single Crystal Diffractometer, uses the time-of-flight Laue technique to access large 3-D volumes of reciprocal space in a single measurement. This makes SXD
especially powerful in applications involving surveys of reciprocal
space, such as phase transitions and incommensurate structures, and also
in applications where sample orientation may be restricted.
SXD
is used for both crystal structure studies and diffuse scattering analysis.
Neutron diffraction is a powerful tool in studies of non-bonded contacts,
specifically those involving hydrogen atoms, thermal parameter analysis,
and in the area of charge density studies where neutron diffraction
data provide complementary information to high resolution X-ray studies.
The
ability to measure a structure at more than one temperature can have
significant benefits, either to characterise thermal parameter behaviour (methyl group librations in paracetamol) or to study disorder (proton transfer in benzoic acid). Diffuse scattering caused by both dynamic and static effects can
be studied, allowing short range structure, defect structure and local
orientational correlations to be probed. A major area of interest is in
developing methods to allow the Bragg and diffuse scattering to be used
together in an integrated way to give a full picture of the structure
under study.
Science Areas.
- Structure determination (including Hydrogen atom location)
- Diffuse scattering (thermally induced disorder, disorder
resulting from defect impurities, or the structure of short range
magnetically ordered systems)
- Phase transitions (including changes of symmetry, and superlattice reflections)
- Incommensurate structures
- Fibre diffraction
History.
In October 1999, a grant
of £1million was awarded by EPSRC to upgrade the SXD detectors. This
allowed for the provision of a total of 11 detectors, almost completely
surrounding the sample position. SXD is currently undergoing a further upgrade of these detectors to new wavelength-shifting fibre modules, increasing the count-rate of the instrument.
