I am using XRF Tornado M5 to analyze some archaeological papyri, and I cannot see the peak of Sodium. However, when I quantify the elements, it gives me 40 % Sodium.
Dear Arzak Mohamed ,
you may share your XRF spectrum,
if there is no peak around 1,04keV, then you are right, there cannot be Na in your sample.
L lines in that energy regime arise from elements having much higher atomic number, such as Zn or Ga.
A sum peak of O K-alpha (2*525eV~1,05keV) may be possible; but unlikely to give 40%...
Maybe there is a wrong energy scale.
So let's have a look at the XRF spectrum.
Best regards
G.M.
Dear Arzak Mohamed, probably the Na content of your samples correlates with the content of another element that was observed by the XRF spectrum.
See in our study (https://www.mdpi.com/2072-4292/12/6/963/htm), we observed good predictions of Mg in soil without the XRF spectrum showing the emission line of this element. However, the concentration of Mg was highly correlated with that of Ca.
Kind regards,
Tiago
Hi Arzak Mohamed, do you know what type calibration are you using? Is it empirical or based on Fundamental Parameters (FP)? Be sure that calibration curve was build with the similar matrix of you sample (papyri has high CHO content). If you are using FP method, use CHO to balance the analyzed elements. I guess that you have used the FP method, because sometimes I have the same problem in my device (overestimating Na content). I solved this issue creating new FP calibration method using similar matrix of my sample to find the coefficients of FP calibration method.
I have attached the spectrum and the Excel sheet for the quantification of the sample.
Thanks , Arzak Mohamed ,
for sharing a spectrum.
As you stated above; there is no peak at the nominal position of Na K line(s).
However, there is a tiny but very broad rectangular structure. I wonder how the software could identify this as Na peak, although there is no explicite peak maximum.
If a peak is erroneously 'found' there, the attenuation correction will give a huge concentration value (like the 40%) due to the strong inherent x-ray attenuation of the 1keV photons in the sample.
You should scan a Na containing sample, e.g. simply NaCl, and see how the Na peak should/will look like. Cl line(s) (~2, 6 to 2,8 keV) should be far enough away from the Na K-line to avoid superposition.
Best regards
G.M.
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