title: Sample-angle feedback for diffraction anomalous fine-structure spectroscopy.
abstract: Diffraction anomalous fine-structure (DAFS) experiments measure Bragg peak intensities as continuous functions of photon energy near a core-level excitation. Measuring the integrated intensity at each energy makes the experiments prohibitively slow; however, in many cases DAFS can be collected quickly by measuring only the peak intensity at the center of the rocking curve. A piezoelectric-actuator-driven stage has been designed and tested as part of a sample-angle feedback circuit for locking onto the maximum of the rocking curve while the energy is scanned. Although software peak-tracking requires only a simple calculation of diffractometer angles, it is found that the additional hardware feedback dramatically improves the reproducibility of the data.
authors.affiliation: Naval Research Laboratory, Washington, DC 20375, USA.
authors.forename: J O
authors.initials: JO
authors.lastname: Cross
authors.forename: W T
authors.initials: WT
authors.lastname: Elam
authors.forename: V G
authors.initials: VG
authors.lastname: Harris
authors.forename: J P
authors.initials: JP
authors.lastname: Kirkland
authors.forename: C E
authors.initials: CE
authors.lastname: Bouldin
authors.forename: L B
authors.initials: LB
authors.lastname: Sorensen