New avenues in x-ray microbeam experiments

The high brilliance of third-generation synchrotron radiation sources allows new applications in x-ray microdiffraction and microsmall-angle scattering. Beam sizes down to about one mu m are routinely used and sub-mu m beam sizes are becoming available, Scanning diffractometry can be used to examine samples like single fibres without the necessity for sectioning, as is required for transmission electron scattering experiments. Examples are taken principally from weakly scattering polymers and biopolymers. In single-crystal diffraction, sub-mu m(3) crystal volumes have been reached for inorganic crystals. Protein crystallography has been demonstrated for a few tenths of mu m linear crystal size, which reduces the crystallization time for many proteins.