Flattening involves removing from the data the difference in slope and quadrature between the pre-and post-edge lines. Because this does not make sense in the pre-edge, Athena multiplies this difference array by a step function centered at E0. If your E0 is not somewhere sensible (i.e. in the swiftly rising part of the spectrum) then you amy see something funny. This question would have been easier to answer had you attached a one-group project file conatining the data in question. Without seeing the data, the only thing any of us can do is speculate as to what is happening. That said, a misplaced E0 value seems like the likeliest answer. HTH, B ________________________________ From: ifeffit-bounces@millenia.cars.aps.anl.gov on behalf of Jens Kruse Sent: Wed 10/01/2007 08:56 To: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] Problems with the >flatten< option in Athena Hi, I have a normalization problem with Athena. If I turn on the "flatten" option in the background removal section, Athena creates in some of the normalized spectra a step in the pre-edge range. How can I get rid of it? Thanks, jens _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit