title: Position and flux stabilization of X-ray beams produced by double-crystal monochromators for EXAFS scans at the titanium K-edge.
abstract: The simultaneous and active feedback stabilization of X-ray beam position and monochromatic beam flux during EXAFS scans at the titanium K-edge as produced by a double-crystal monochromator beamline is reported. The feedback is generated using two independent feedback loops using separate beam flux and position measurements. The flux is stabilized using a fast extremum-searching algorithm that is insensitive to changes in the synchrotron ring current and energy-dependent monochromator output. Corrections of beam height are made using an innovative transmissive beam position monitor instrument. The efficacy of the feedback stabilization method is demonstrated by comparing the measurements of EXAFS spectra on inhomogeneous diluted Ti-containing samples with and without feedback applied.
authors.affiliation: School of Electrical and Electronic Engineering, The University of Manchester, Sackville Street, Manchester M13 9PL, UK.
authors.forename: Roelof
authors.initials: R
authors.lastname: van Silfhout
authors.affiliation: School of Electrical and Electronic Engineering, The University of Manchester, Sackville Street, Manchester M13 9PL, UK.
authors.forename: Anton
authors.initials: A
authors.lastname: Kachatkou
authors.affiliation: Department of Chemistry, NIS Center of Excellence, CrisDi Center for Crystallography, and INSTM Unit, University of Turin, Via Giuria 7, Turin I-10125, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Groppo
authors.affiliation: Department of Chemistry, NIS Center of Excellence, CrisDi Center for Crystallography, and INSTM Unit, University of Turin, Via Giuria 7, Turin I-10125, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Lamberti
authors.affiliation: Netherlands Organization for Scientific Research (NWO), Dubble, ESRF, 6 Rue Jules Horowitz, 38043 Grenoble, France.
authors.forename: Wim
authors.initials: W
authors.lastname: Bras
keywords: EXAFS; Ti K-edge; beam intensity stabilization; beam position control; monochromator