Hi George,
On Tue, Apr 1, 2014 at 11:56 AM, George Sterbinsky
Hi Matthew,
Hephaestus shows the strength of the Ll emission to be about 10% of the La2 emission. When fitting the spectrum as a sum of Gaussians, I find that the area of of the Gaussian used to fit the Ll is 24% of that used to fit the La2. What would cause the ratio determined from tabulated data to differ from that found in the data I collected? Am I misunderstanding the meaning of the "strength" value in Hephaestus?
Thanks, George
Strength here means "fraction of the X-rays emitted from the decay of the initial level". So, well above L3 edge, Ll should be ~10% of La1,2. Well above L2 edge, Ln should be ~10% of Lb1,2. Those values of branching could be somewhat approximate. It's also possible that they don't properly account for the Coster-Kronig process (inter-shell transitions, known to be important for L shells, especially low energy lines where Auger transitions dominate). I thought they did take this into account, but perhaps that's not correct. of the correction is It wasn't completely clear what your incident energy is, but there are also elastic and Compton peaks to consider. I think the elastic line being folded into your main peak would tend to make the ratio of La1,2 to Ll (Lb1,2 and Ln) bigger, which seems to be the wrong way. It seems the incident energy was below the L1 edge (925 eV), because the Lb3,4 peaks (~855 eV) are missing... Then again, if the detector was at 90deg in the horizontal plane from a synchrotron source, the elastic peak may be tiny. Compton scattering might appear to increase the low energy side of the peak. I think you'd have to do a more careful analysis with the energy well above all Co L edges with a well-resolved Compton peak separated from the L lines to do a more quantitative analysis. Finally, it's known (perhaps not well-known) that the peaks are slightly asymmetric, with a low energy tail. This is usually a small effect, but perhaps it's part of what you're seeing. All that said, I don't have a lot of experience working at such low energies. --Matt