[Ifeffit] Self-Absorption Corrections
Peter Pfalzer
peter.pfalzer at physik.uni-augsburg.de
Fri Jul 25 03:59:40 CDT 2003
Hi all,
> Corwin Booth (at LBL lab, Berkeley) presented a very nice procedure
> for making these corrections for EXAFS at the conference, improving
> the work of L. Troger, et al from the mid 1990's.
> I'd be interested in hearing others opinions on this topic, and
> whether this should be included in Ifeffit.
Corwin Booths approach to selfabsorption correction seems to be very
nice. I think that especially its possibility to give up the "infinite
sample thickness" limitation could be an important improvement over the
previous approaches.
Still, it makes two (more or less implicit) assumptions:
* the detector surface has to be parallel to the x-ray beam (phi + theta
= 90 deg)
* the detector has to have a neglectable solid angle
I'm not sure if these two assumptions hold for most fluorescence
experiments?
When I collected my last fluorescence data a couple of years ago, large
solid angle detectors (like Lytle-detectors) were still in use. I have
shown that Troegers approach to selfabsorption correction can be
generalized for large detector surfaces (Phys. Rev. B 60, 9335 (1999)).
In principle this should be also possible for Corwin Booths formula.
But when integrating over large solid angles, the exact geometry of the
experimental setup plays a crucial role in determining the
selfabsorption correction and I doubt that a useful implementation into
iFeffit would be possible.
If, however, everyone is using solid state detectors now, I would say
that implementing Corwin Booths code into iFeffit could be worth the effort.
Best,
Peter
--
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Peter Pfalzer
Universitaet Augsburg Tel: +49-821-598-3215
Lehrstuhl fuer Experimentalphysik II Fax: +49-821-598-3411
Universitaetsstr. 1
D-86135 Augsburg
Germany Peter.Pfalzer at physik.uni-augsburg.de
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