Open AccessSample‐angle feedback for diffraction anomalous fine‐structure spectroscopy
Author(s) -
Cross J. O.,
Elam W. T.,
Harris V. G.,
Kirkland J. P.,
Bouldin C. E.,
Sorensen L. B.
Publication year - 1998
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049597014313
Subject(s) - diffraction , sample (material) , bragg peak , diffractometer , optics , intensity (physics) , energy (signal processing) , materials science , reproducibility , bragg's law , computational physics , physics , chemistry , beam (structure) , scanning electron microscope , thermodynamics , chromatography , quantum mechanics
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.