AN INVESTIGATION OF THE PERFORMANCE OF A NOVEL DOUBLE CRYSTAL X-RAY MONOCHROMATOR FOR EXAFS AND XANES MEASUREMENTS

摘要

A new double crystal x-ray monochromator for EXAFS and XANES measurements is described. The monochromator is designed to provide high intensity with good resolution by the use of bent crystals, when used on line 8 of the Daresbury Synchrotron Radiation Source. The details of the monochromator design have been reported before [1]. Examples of EXAFS spectra demonstrate the success of this design. Further aspects of the performance are considered. The stability of the monochromator, its ability to remove harmonics from the monochromatic beam and the use of doubly bent crystals to provide focussing are reported. Finally, the appearance of anomalies in the output of the monochromator is shown to arise from multiple diffraction effects. These effects and efforts to minimise or remove them are discussed.