Lachlan:
>Is there GEM related information on available software (or portability
>tools) that are being developed in parallel with the hardware so that GEM
>can produce "usable" and "analyzable" data?
Yes, we have a major software effort to handle these data and reduce them
down to manageable s
dear all,
since standard data formats were mentioned, I would just like to draw your
attention to the NeXus project, which has the (ambitious) purpose of
developing a unified data format for x-rays and neutrons.
http://www.neutron.anl.gov/NEXUS/
http://lns00.psi.ch/NeXus/
The NeXus format is ba
>I had the impression that neutron diffraction requires a large amount of
>sample. Isn't this a limitation is some cases ?
This is true to a certain extent, although it depends on the complexity of
the structure and on the elemental content. To get reasonable statistics at
very high resolution,
Hey, it looks like we are really accomplishing something with this
discussion. Only three days ago, neutrons were hoplessly at the bottom of
the resolution league, "one order of magnitude away" from the leader. Now,
neutrons squeezed past conventional x-rays and are in hot pursuit of
synchrotron
Oops. I meant http://www.ill.fr/dif/hrpd-mgo.txt
Paolo
Dear All,
so that we don't have to wait until Bill comes back...
I sent a portion of an MgO pattern taken with HRPD to Alan, and he kindly
put it on his www server: http://www.ill.fr/dif/hrpd-mgo.doc. It's a simple
text file. I converted the data to 2th, using a popular synchrotron
wavelength
>What is left is small fry and we will gladly leave it to x-rays, since
>we are so much better at virtually everything else.
Sorry for the half-serious joke. I really appreciate and use x-rays, but I
cannot avoid thinking that synchrotron x-rays are often used in powder
diffraction for their "ex
Dear All,
let's get some straight facts about neutron resolution. The 'important'
resolution is not the 2theta FWHM, but the deltad/d FWHM. Now, everybody
knows this formula:
deltad/d=[(cot(theta)dtheta)^2+dlambda/lambda^2]
This, combined with Bragg's law, yields:
deltad/d=[d
Well, it looks like my "feeling" might have been wrong this time. The way
you may want to go through the "tedious" proof is the following.
1) You construct the Aij matrix (also sometimes called the Hessian matrix)
Aij=D^2chi^2/DxiDxj (D is the partial derivative sign. E-mail is
Jon Wright wrote:
>I guess the degradation which is found would come from parameters which
>are determined by both datasets and come out with different values in each
>separate refinement.
Not necessarily. In order to get the ESD, the variance-covariance matrix is
multiplied by chi^2, and the
Alexandros Lappas wrote:
>Does anybody have experience analysing HRPD (Time-of-Flight) diffraction
>patterns with the FULLPROF program?
>From recent discussions with Juan Rodriguez-Carvajal (April 1999), I
gathered that the TOF version of FULLPROF is still rather experimental, and
it does not w
Dear All,
here is my (biased) opinion on the whole matter.
1) Intensity data: neutron powder diffraction *always* yield better
intensity data than x-ray powder diffraction, including synchrotron.
Contrary to popular belief, this is true not only for mixtures of heavy and
light atoms, but also f
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