Dear All,
Due to a laboratory diffractometer purchase I'm making a pros and cons
list for two configurations:
1) Theta-2theta Bragg-Brentano geometry & Johansson primary beam
monochromator.
2) Omega-2theta parallel beam geometry with primary beam 2-bounce flat
crystal monochromator.
Point of view being in powders and Rietveld analysis.
I have papers "N.A. Raftery & R. Vogel, J. Appl. Cryst. 37 (2004) 357
(DOI: 10.1107/S0021889804003097)" and "M.S. Haluska, S. Speakman and
S.T. Misture, ICDD 2003 Advances in X-ray Analysis, Vol 46 p. 192" where
similar comparisons are made, main difference being that in both works
primary beam monochromators were not used.
Before reading the papers I was under impression that Bragg-Brentano
geometry is definetely the best choice for indexing, structure solution
and Rietveld analysis. But now I'm not so sure anymore. According to
these papers the differences between the results from parallel beam and
Bragg-Brentano data are very small.
Any comments on these two different geometries here on Rietveld list? Or
if you could recommned some relevant references?
Best Regards,
Markus Valkeapää
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Dr. Markus Valkeapaa
Department of Chemistry, Helsinki University of Technology
P.O. Box 6100, FI-02150 TKK
Office: Kemistintie 1, room B206
tel: +358 50 511 3073, +358 9 451 2596, +358 44 290 2515
fax: +358 9 462 373
email: markus.valkea...@tkk.fi
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