Dear Kurt,
You can peaksearch the images with any number of packages and then look
at the extracted spot positions. The stuff we wrote lives at
http://sourceforge.net/projects/fable/ and it is normally used to fit
grain-by-grain strain tensors. If you can isolate the spots you do
indeed get a large improvement in resolution (centre of mass versus
width is typically a factor of 10). If you can rotate the sample and
collect a full data set you can process them all as single crystals.
There is a blob searching algorithm in pyFAI which pulls out the peak
positions out for you in the course of doing calibrations
(github.com/kif/pyFAI).
In keeping with the subject line: is it a regress or progress to go back
to using single crystals instead of powders? There is a rumour going
around (http://dx.doi.org/10.1107/S2052252515004017) that the days of
"powder diffraction" may be numbered :-)
Best,
Jon
On 08/05/2015 23:29, Kurt Leinenweber wrote:
P.S. When the splitting arises from a phase transition, sometimes we
see what we call "snowmen" or pairs of spots that are split between
the two rings. I interpret these as twins arising from the phase
transition. Has anyone seen these types of pairs of spots before? I
think there is a lot of information there that we are passing up if
we don't learn to interpret it.
Hi all,
In my defense, 10 of the 12 messages relating to this topic have
had their footers attached. I will try to figure out how to get
rid of it for next time.
Here is a topic I am interested in: we are collecting a lot of data
on an imaging plate (GSECARS and HPCAT at Advanced Photon Source).
We are interested in splitting of peaks in some of the samples.
The splitting is very difficult to see on the integrated pattern,
but very easy to see on the 2-D imaging plate frame itself. The
rings are "spotty" and it's very easy to tell which spots are in
which ring when the peak is slightly split.
My question is whether there is software I can use to take
advantage of this and fit the "spots" so I can get a better
resolution of the splitting. Something in between powder and
single crystal.
Thank you,
- Kurt
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