2013/11/21 by Michael Hart, Michael Drakopoulos, Hart, Michael L. +1
Arts and Humanities · Chemistry · Materials Science · #Crystallography and molecular interactions #Cultural Heritage Materials Analysis #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #X-ray Diffraction in Crystallography
paper · pdf · doi:10.48550/arxiv.1311.5430
openalex publication_date 2013/11/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We present a procedure for fitting an ellipse to powder diffraction patterns recorded on a planar 2D detector, which uses the peak intensities as weights. This procedure works for complete and spotty diffraction rings. We outline all the steps required: the interpolation of Cartesian pixel data into polar co-ordinates based upon an approximate ellipse centre; the identification of peak locations along each radial direction of a diffraction ring; and the weighted least squares algebraic fit of an ellipse to that diffraction ring. The performance of the procedure is assessed by characterising a complete diffraction ring from a powder standard, and a spotty ring generated from a complete ring of the standard. The fit of an ellipse to a spotty ring from an alkane complex is also shown. Agreement in the calculated parameters for the two rings is good. This procedure is implemented as part of an X-ray beam energy and 2D detector calibration routine which is currently in use at Beamline I12 (Diamond Light Source, UK).