Dear Colleagues:
Commission on Powder Diffraction of the IUCr is sponsoring a round robin on
diffraction line-broadening effects of coherent domain size and
(micro)strain in materials. The first round-robin sample is CeO2 powder,
synthesized at the University of Rennes. The intent in the first round-robin
phase is to look at different methods of line-broadening analysis and come
up with recommendations on applicability and reliability of different
methodologies. For this reason, measurements at different instruments were
carried out on the CeO2 samples as follows:
- Laboratory x-ray (University of Birmingham and University of Le Mans);
- Synchrotron x-ray (NSLS and ESRF)
- CW neutron (ILL and NCNR)
- Spallation neutron (ISIS)
Round-robin participants are invited to select either one or several methods
from the following list and to carry out the line-broadening analysis on the
data:
- Stokes deconvolution + Warren-Averbach analysis
- Modified Williamson-Hall analysis (Lorentz function for the size-broadened
profile and Gauss function for the strain-broadened profile)
- "Double-Voigt" analysis (Voigt function for both size-broadened and
strain-broadened profiles)
- Rietveld-refinement analysis -- modified TCH line-broadening model (GSAS,
DBWS, FullProf) and Fourier series profile synthesis (ARIT).
- "Fundamental-parameter" approach -- this way, the results obtained by
different methods that use annealed CeO2 as an "instrumental standard" can
be compared to this "standardless" method.
If you are interested, there is still time to join. The enrollment form,
measurements, and recommendations that you should follow to insure
consistent data analysis across different methods are available at
http://www.boulder.nist.gov/div853/balzar/ or from the European CCP14 mirror
at the http://www.ccp14.ac.uk/ccp/web-mirrors/balzar/div853/balzar/
The deadline for returning the results to the Round-Robin organizer is set
for October 20, 2000!
Your participation is greatly appreciated. Good luck with the data!
Davor Balzar
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National Institute of Standards and Technology
Materials Science and Engineering Laboratory
Div. 853, 325 Broadway
Boulder, CO 80305-3328
Tel: 303-497-3006
Fax: 303-497-5030
E-mail: [EMAIL PROTECTED]
Web: http://www.boulder.nist.gov/div853/balzar
European mirror:
http://www.ccp14.ac.uk/ccp/web-mirrors/balzar/div853/balzar/
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