[Ifeffit] Dodgy Edge Steps

Stefan Mangold stefan.mangold at iss.fzk.de
Mon Apr 28 11:46:07 CDT 2008


the edge step should be less than 1; the edge step at white line  
should be not higher than 1.5 and die maximum absorption should not be  
higher than 2.7 (max. 3) (reason is the signal to noise ratio). The  
reason for limiting the edge jump are none linearities of your  
detector systems. So I would not use the data for further analysis.

best regards

Dr. Stefan Mangold
Institut für Synchrotronstrahlung
Forschungszentrum Karlsruhe

Am 28.04.2008 um 18:27 schrieb LACHLAN MACLEAN:

> Hi All
> Long-term lurker, first time poster.
> I've recently collected some EXAFS data with a large edge step  
> (~3.4) and for some reason didn't pick up on it until it was too  
> late.  I've been told that ideally we would want an edge step of 1  
> and anything above ~1.5-2 is too high.  I'm wondering if there is a  
> way to salvage the dataset in order to compare it with EXAFS data  
> that I collected from two other samples (all three are supposed to  
> be synthetic goethite).  The first two samples that I want to  
> compare have edge steps of about 0.35.
> I know Athena allows one to adjust the edge step but wonder how  
> appropriate this is and how much change this would cause the EXAFS  
> data?  Trying to adjust the edge step from 3.4 down to ~1 or so  
> seems to be quite a jump.  I'm curious whether there is a way to  
> salvage this data rather than wait until the next beamrun.
> Any help would be appreciated.
> Cheers
> Lachlan
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