Multiple‐order reflections from monochromating crystals for the collection of X‐ray absorption spectra at extremely high energies

A simple method to collect X‐ray absorption spectra at extremely high energies (50 keV) is presented. The method is based on the use of the third harmonic signal from a conventional double‐crystal monochromator. Strengths and limitations of the method are shown, together with a few experimental examples on metallic foils and oxide powders in transmission and fluorescence mode.