Julian, On Fri, May 25, 2018 at 9:01 AM Julian Ehwald wrote:

Dear Matt,

Thank you for your superfast answer. I obtained new data from the people at the beamline today, and the set contains both Total electron Yield and Total fluorescence yield. As far as I understand, they both tell us something about the absorption. Which is usually used for analysis? If I process them with Athena I get considerable differences…

​Please use the mailing list. Either or both of total electron yied and total fluorescence yield can be used for XAFS. That is, total emission of high-energy electrons and emission of fluorescence X-rays are both proportional to the absorption cross-section for an atom, at least to first approximation. There are complications in using these. For X-ray fluorescence the main complication is "over absorption" which happens in materials in which the element of interest is high concentration (effects can be noticeable at ~1% and are usually significant-but-correctable up to ~10%, and are nearly impossible to correct above ~50% concentration). For electron yield, the main complication is that the electron escape depth is shallow enough that the measurement may be more sensitive to the surface than the bulk of the sample. That sort of depends on how you define "surface" (the electrons escape from 10s to 100s of Angstroms), but can be seen as an advantage if surface sensitivity is what you want. For both, using the data as XAFS means using mu ~ EmissionIntensity / I0. That's very different from transmission data, which often trips people up when importing the data into Athena: DO NOT use the log( EmissionIntensity / I0), use EmissionIntensity/I0. --Matt