Small-angle X-ray scattering at high energies

Initial tests are described of a high-resolution small-angle X-ray scattering apparatus adapted for operation at high photon energies. The energy chosen was 50 keV, and was limited by the available source. All orders of scattering out to the seventh were observed from a sample of 0.9 μm diameter latex spheres in a 4 h experiment. Phase separation in a binary Al–Li alloy was studied by the observation of spherical Al₃Li precipitates. This demonstrates that the use of perfect-crystal collimators and analyzers yields a resolution function which does not depend on photon energy. New sources of high-energy photons will make such an apparatus invaluable for the study of highly absorbing samples, or samples in difficult environments such as ovens or high-pressure cells.