Dear SM or MS
With this geometry the incident beam to sample angle (alpha) is usually fixed
at a small value (say, 2 - 10degrees).
If you have the ability to scan the sample axis (omega - i.e. changing alpha),
then (i) conduct an omega scan (this could be done manually if necessary), (ii)
extract individual intensities of peaks of interest, (iii) correct the peak
intensities for the geometry used*, and (iv) plot the corrected intensities as
a function of alpha. If you have preferred orientation along a specific
direction them the plot should show a maximum at (alpha = 0.5 * 2Theta) for
that reflection. If there is no preferred orientation, then the plot of
corrected intensities should have a constant value as a function of alpha.
* This intensity correction is fairly simple and takes into account the
difference in beam path for the incident and diffracted beams. It relies on
knowledge of the incident beam to sample angle (alpha) and the diffracted beam
to sample angle (beta) where (alpha + beta) = 2Theta. It has been described
nicely by Toraya et al
H. Toraya, T. C. Huang and Y. Wu
Intensity enhancement in asymmetric diffraction with parallel-beam synchrotron
radiation
J. Appl. Cryst. (1993). 26, 774-777 [ doi:10.1107/S0021889893004881 ]
Cheers
o----------------------------oo0oo----------------------------o
Ian Madsen
Team Leader - Diffraction Science
CSIRO Process Science and Engineering
Box 312, Clayton South 3169
Victoria, AUSTRALIA
Phone +61 3 9545 8785 direct
+61 3 9545 8500 switch
+61 (0) 417 554 935 mobile
FAX +61 3 9562 8919
Email ian.mad...@csiro.au
o----------------------------oo0oo----------------------------o
From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On Behalf Of
SM
Sent: Tuesday, 25 March 2014 3:19 PM
To: rietveld_l@ill.fr
Subject: PO in parallel beam flat-plat geometry -reg
Dear all,
please clarify my doubt, this may be very old one, even though please clarify
how to find Preferred Orientation in parallel beam flat-plat geometry with CPS
detector.
kindly clarify my doubt
Thank you,
regards
MS
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