Instrument-model refinement in normalized reciprocal-vector space for X-ray Laue diffraction

J Appl Crystallogr. 2020 Sep 29;53(Pt 5):1370-1375. doi: 10.1107/S1600576720011929. eCollection 2020 Oct 1.

Abstract

A simple yet efficient instrument-model refinement method for X-ray diffraction data is presented and discussed. The method is based on least-squares minimization of differences between respective normalized (i.e. unit length) reciprocal vectors computed for adjacent frames. The approach was primarily designed to work with synchrotron X-ray Laue diffraction data collected for small-molecule single-crystal samples. The method has been shown to work well on both simulated and experimental data. Tests performed on simulated data sets for small-molecule and protein crystals confirmed the validity of the proposed instrument-model refinement approach. Finally, examination of data sets collected at both BioCARS 14-ID-B (Advanced Photon Source) and ID09 (European Synchrotron Radiation Facility) beamlines indicated that the approach is capable of retrieving goniometer parameters (e.g. detector distance or primary X-ray beam centre) reliably, even when their initial estimates are rather inaccurate.

Keywords: Laue diffraction; X-ray diffraction; data processing; instrument models; refinement.