Absolute energy calibration of X-ray radiation from synchrotron sources

A new apparatus and technique to determine the absolute energy of X-rays from a synchrotron source were used to establish the absolute energy of the zinc metal K absorption edge [9661.1(2) eV] and to measure systematic errors in the angular settings of a typical rotation table used for X-ray spectroscopy. These errors have a period of 1° associated with the worm gear of the rotation table and should provide a warning to other synchrotron radiation spectroscopists that systematic errors exist in experimental data. The technique relies on determining the orientation of a static silicon crystal with respect to the incoming beam by establishing degenerate reflections with differing Miller indices. Absolute energies can be determined for X-rays with energies greater than 6 keV. An analysis of the system shows that the technique is also useful for the accurate characterization of the monochromator resolution.