[Ifeffit] Peaks in Background Subtraction in Athena

[Nathan Nakamura]

Hello,

I am working on some data processing of ZrO2 thin films collected in
fluorescence mode, and had a question regarding the background subtraction
in Athena. When I use the default values, I see a large negative spike in
the background curve (shown in BGsubtract1.png). I can vary the spline
clamps and other parameters to reduce this (BGsubtract1.copy), but it does
not seem to have any significant effect on the final EXAFS
(EXAFScompare.png).

My question is, do large spikes/instabilities on the edge like this need to
be accounted for, or are they ok as long as the background fit after the
edge seems fine? My thought is that as long as the EXAFS is not
significantly affected, it should be fine, but I do not have a good sense
for how the presence of this peak may impact the background curve beyond
the absorption edge. I have also attached the project file in Athena for
reference.

Thanks,
-Nathan
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