title: Novel angular encoder for a quick-extended x-ray absorption fine structure monochromator.
abstract: New concepts for time-resolved x-ray absorption spectroscopy using the quick-extended x-ray absorption fine structure (QEXAFS) method are presented. QEXAFS is a powerful tool to gain structural information about, e.g., fast chemical reactions or phase transitions on a subsecond scale. This can be achieved with a monochromator design that employs a channel-cut crystal on a cam driven tilt table for rapid angular oscillations of the Bragg angle. A new angular encoder system and a new data acquisition were described and characterized that were applied to a QEXAFS monochromator to get spectra with a directly measured accurate energy scale. New electronics were designed to allow a fast acquisition of the Bragg angle values and the absorption data during the measurements simultaneously.
authors.affiliation: Fachbereich C, Physik Bergische Universitat Wuppertal, Gaussstr. 20, 42097 Wuppertal, Germany. j.stoetzel@uni-wuppertal.de
authors.forename: J
authors.initials: J
authors.lastname: Stötzel
authors.forename: D
authors.initials: D
authors.lastname: Lützenkirchen-Hecht
authors.forename: E
authors.initials: E
authors.lastname: Fonda
authors.forename: N
authors.initials: N
authors.lastname: De Oliveira
authors.forename: V
authors.initials: V
authors.lastname: Briois
authors.forename: R
authors.initials: R
authors.lastname: Frahm