Slits and high-resolution X-ray diffraction

It is shown that, with proper use of an anti-scatter slit in front of the detector, the signal-to-noise ratio of a symmetric high-resolution X-ray diffraction scan can be improved by a factor of ten. By the use of an asymmetric reflection with a high angle of incidence on the sample, the size of the diffracted beam can be reduced sufficiently to allow for two-dimensional reciprocal-space scans with a simple slit instead of a crystal assembly in front of the detector for enhanced resolution. By selection of the proper reflection, a resolution can be chosen that suits the application. Examples include a partially relaxed SiGe multilayer and a periodic surface grating.