Performance of the ESRF ID26 beamline reflective optics

Abstract

This paper presents the experimental results obtained during the commissioning of the X-ray mirrors installed on the ESRF beamline ID26. The ID26 spectrometer is dedicated to XAFS studies on ultra-diluted samples in the energy range 2.3 - 25 KeV using the excitation of X-ray fluorescence. The beamline has been open to external users since January 1998 and all the main optical elements are fully commissioned. The reflective optics layout consists of three devices: a high heat load deflecting mirror installed in the white beam section and a classical Kirkpatrick-Baez couple installed downstream the monochromator. The focusing mirrors are based on the multi-segmented piezoelectric mirror technology and allow for a continuos and very precise adjustment of the curvature. Spot sizes as small as 170 × 7 (hor. x vert) μm2 FWHM can be easily achieved, with a total flux well in excess of 1013 photons s-1 when using Si 220 monochromator crystals.