Specimen-displacement correction for powder X-ray diffraction in Debye-Scherrer geometry with a flat area detector

Benjamin S. Hulbert, Waltraud M. Kriven, H. Brand

Research output: Contribution to journalArticlepeer-review

Abstract

The effect of small changes in the specimen-to-detector distance on the unit-cell parameters is examined for synchrotron powder diffraction in Debye-Scherrer (transmission) geometry with a flat area detector. An analytical correction equation is proposed to fix the shift in 2θ values due to specimen capillary displacement. This equation does not require the use of an internal reference material, is applied during the Rietveld refinement step, and is analogous to the specimen-displacement correction equations for Bragg-Brentano and curved-detector Debye-Scherrer geometry experiments, but has a different functional form. The 2θ correction equation is compared with another specimen-displacement correction based on the use of an internal reference material in which new integration and calibration parameters of area-detector images are determined. Example data sets showing the effect of a 3.3 mm specimen displacement on the unit-cell parameters for 25°C CeO2, including both types of displacement correction, are described. These experiments were performed at powder X-ray diffraction beamlines at the National Synchrotron Light Source II at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory.

Original languageEnglish (US)
Pages (from-to)160-166
Number of pages7
JournalJournal of Applied Crystallography
Volume56
DOIs
StatePublished - Feb 1 2023

Keywords

  • Debye-Scherrer
  • area detectors
  • displacement correction equation
  • powder X-ray diffraction
  • specimen-to-detector distance
  • transmission

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology

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