Energy determination of synchrotron X-ray beam energy in the high energy region of 38–50 keV using powder diffraction patterns of the standard powder Si640b

Powder diffraction patterns from SRM Si640b are used to calibrate the energy scale for two experiments using a monochromated synchrotron X-ray beam in the high energy region 38–50 keV. The energy of the beam is determined to accuracies between 0.0007% and 0.07% of the beam energy. Uncertainties in the energy scale are reduced by correcting for the zero offset angle of the monochromator crystal. Corrections of between - 150 and 50 eV are applied to the nominal beam energy. It is shown that systematic errors arising from the misalignment of the monochromator can lead to large systematic shifts in the beam energy.