We've been working with the X'Pert Pro platform and were one of the first to
receive the system. Officially, our gonio is still an X'Pert MPD, but we've
got the click-on optics, so it's actually an early Pro. Though we've had
some problems with the goniometer (the counterweights, the motors, etc.), we
were able to solve them in collaboration with Philips.
One item is especially important for Rietveld work, namely the peak
asymmetry due to axial divergence. Generally, Philips delivers 0.04 rad
Soller slits with its optics, but these Sollers produce quite important
asymmetry even at the higher angles. It proved extremely difficult to fit
these peaks, even using a Pearson VII, without resorting to fundamental
parameters approaches. We have recently performed quite a large amounts of
tests and calculations to find out how we could reduce the asymmetry and
what optics is best suited for Rietveld spectral acquisition. I will
shortly send a few pages as a report of this to this list. In any case, it
is imperative that 0.02 rad Soller slits are purchased from Philips to get
decent spectra for Rietveld use.
As far as software goes, the X'Pert Plus package is the Rietveld refinement
software Philips delivers. Although it is not THE most powerful package in
existance, it is definately the most easy to use and very versatile. It is
based on the LHPM engine, but it has an easy-to-use GUI, without reducing
the control of the user over the refinement process. The fact that it even
allows refinement of neutron spectra and it can read .RAW Bruker data proves
that the people from Philips have tried to produce a product with a lot of
features and not just oriented towards their goniometer.
I'll be happy to answer specific questions on the X'Pert Pro system.
Sven Van den Berghe
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Sven Van den Berghe
Assistant Scientific Researcher
Reactor Materials Research Department (RMO)
Laboratory for High and Medium Activity (LHMA)
Boeretang 200
B-2400 Mol
Belgium
Tel. : +32 14 33 30 64
Fax : +32 14 32 12 16
E-mail : <mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED]
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