Jens, Let me give you an old reference (but still usefull) for the self absorption treatment:
R. CastaƱer and C. Prieto, "Fluorescence detection of EXAFS in thin film samples", J. de Phys. III (France), 7, 337-349 (1997). Best regards Carlos Prieto At 15:51 02/02/2009, you wrote: >Jens, > >Since no one has answered yet, I'll chime >in. First let me direct you to a discussion of >self-absorption and other sample-related >distortions: ><http://www.xafs.org/Experiment/OverAbsorption>http://www.xafs.org/Experiment/OverAbsorption > >(this is a link from the tutorials page of <http://www.xafs.org>www.xafs.org). > >As for your questions: > >I think that you should use the non-normalized >XANES data to perform the SA correction. > >for the angle-in and angle-out meanings, see >Grant Bunker's paper on self-absorption >here: ><http://gbxafs.iit.edu/training/Self_Absorption_effects.pdf>http://gbxafs.iit.edu/training/Self_Absorption_effects.pdf > >Now, how do you determine if you have >self-absorption effects? I have to defer here >to those with more experience. What you suggest >sounds appropriate, but I'm not sure how you >could determine this without studying multiple >concentrations of your absorber and watch the >signals, i.e. does a 10% increase in absorber >concentration translate to a 10% increase in >fluorescence yield (similar to what Matthew >Marcus and Alain Manceau describe in their >paper, from the over-absorption link above). > >HTH, >-Rich > >On Fri, Jan 30, 2009 at 11:49 AM, Jens Kruse ><<mailto:jens.kr...@uni-rostock.de>jens.kr...@uni-rostock.de> wrote: >Hi there, > >I have measured a pure reference compound with high absorber >concentration in fluorescence mode (P K-edge XANES). I tried to use the >Self absorption correction included in Athena but I don't really >understand the results. >Fist: Do I have to use the edge step normalized spectrum or the spectrum >without normalization ? I tried both and the results of course a quite >different. I would rather use the not normalized spectrum. >Second: the value "Angel in" is this the angle between the incident >beam and the sample surface" and "Angle out" the angle between the >sample surface and the detector position? >Third: More general- How can I identify a spectrum suffering self >absorption? Just comparing the relative peak intensities of total >electron yield signal with the fluorescence yield signal ? > >thanks a lot for your comments, >cheers, > Jens > >-- >Jens Kruse >Institute for Land Use >Faculty for Agricultural and Environmental Sciences >Rostock University >Justus-von-Liebig-Weg 6 >18059 Rostock GERMANY >Phone: +49(0)381-498 3190 > >_______________________________________________ >Ifeffit mailing list ><mailto:Ifeffit@millenia.cars.aps.anl.gov>Ifeffit@millenia.cars.aps.anl.gov >http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > > >_______________________________________________ >Ifeffit mailing list >Ifeffit@millenia.cars.aps.anl.gov >http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit ================================ Carlos Prieto Instituto de Ciencia de Materiales de Madrid CSIC Cantoblanco, 28049 - MADRID (Spain) Tel.: 91 3349017 e-mail: cpri...@icmm.csic.es ================================= _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit