One of the big sources of background could be harmonics fluorescing Fe, especially for S. Aside from that, it only takes light filtering with something like mylar to knock down Si and Al in favor of S and Ca. You need a beamline which doesn't have a lot of Be in the way so that it can get decent flux at the S edge. There are a number of "tender X-ray" beamlines out there, for instance at CLS. The one I've been working on, ALS 10.3.2 can also do it, though it doesn't have as much flux as some of the others, being a microprobe on a bend magnet. If there's any Cl, that could interfere with S. mam On 5/10/2014 9:02 AM, Marcelo Alves wrote:

Dear all,

I am interested in running some measurements of XANES and EXAFS K-edge spectra of elements such as Ca and S sorbed onto commonly found oxisol minerals, i.e natural kaolinite, gibbsite, hematite, and goethite. Besides appropiate filters to attenuate the fluorescence signals that come from elements such as Al and Si, what would the other instrumental conditions (e.g detector type, photon flux, etc...) needed for getting usable spectra of those elements in diluted samples? Any suggestion on the more adequate beamline to carry out such measurements?

Kind regards,

Marcelo.

_______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit