Synchrotron X‐ray powder diffraction

摘要: The application of synchrotron X-ray radiation to powder diffraction is described. A perfect Si double-crystal monochromator at the Cornell High Energy Synchrotron Source (CHESS) was used in conjunction with Si, Ge, LiF and Al2O3 analyzers investigate resolution intensity characteristics selected wavelengths between 1.07 1.54 A. results obtained Ge 1.54 A gave a Δd/d 5 × 10−4 2θ = 30°, falling 2 140°. Analysis peak shapes described detail, particular emphasis on asymmetry observed angles below 50° due axial divergence effects. With simple correction allow for these, are found be well represented by convolution Gaussian Lorentzian components, respective widths these being related intrinsic sample broadening It pointed out that use crystal analyzer should eliminate shifts Bragg-peak positions owing displacement-type aberrations which occur conventional focusing-type diffractometers. Except constant zero error, mean discrepancy calculated 0 90° reference samples CeO2, NiO only about 0.003°. Finally, some general remarks made Rietveld profile technique structural analysis from data.