Dear Anna Karakasi ,

I do not know your samples, so I cannot exclude any Zn content.

But what is the outcome of your XRF device when scanning samples which definitely do not contain any Zn?

So check e.g. with water (no lines but a lot of Compton scatter) or e.g. the wall of your lab ( Ca & Ba K-alpha lines) as samples.

If Zn shows up, then it is an error of your device.

Dear Gerhard Martens ,

Thank you for your answer!

All my samples are Cu-Sn alloys, and they contain Zn, but in a small percentage.

The problem is that the Zn peak looks a lot bigger than the Sn peak.

I did some tests on a Cu-Zn alloy sample, and the spectrum looks normal.

Υou can see the xls file I attached, to understand what I mean.

Dear Anna Karakasi ,

thanks for feed back.

The Zn peak height is larger than that of the Sn peak.

But what is about the colouring of the Zn peak. There is a colouring only at its low energy part. Does that mean that only that coloured part matches the Zn line fit; and thus one has to look for a fluorescence line which is just below the Zn K-alpha from the photon energy point of view?

But when carefully looking at your energy scale one will see, that the coloured part is just at the position of the Zn K-alpha.

With respect to the concentration you should compare the coloured areas of Zn and Sn and not the peak heights.

Dear Anna,

as Gerhard Martens suggested, a test with a 100% Zn-free sample would be helpful!

But, by the way, looking at your data, you are not having any Zn contamination, this is simply the Cu K-beta line which is located at 8905 eV, and Zn would be at 8630 and 9572 eV. If it would really be Zn, than you should also see the K-beta of Zn ... See the X-ray fluorescence peak position energies listed e.g. in

https://xdb.lbl.gov/Section1/Table_1-2.pdf

Your spectrometer is not at all damaged! Good news, ain't it?

Best regards, Dirk

Dear Gerhard Martens and Dirk Luetzenkirchen-Hecht ,

Thank you so much for your answers! You were both very helpfull!

I suspected that it has something to do with the K lines and now I know what to look for. I will also do some tests with a 100% Zn-free sample, to be sure.

Best regards,

Anna Karakasi

Dear Anna Karakasi ,

Dirk Luetzenkirchen-Hecht is right. The coloured portion within the pretended Zn line profile is Cu K-beta, which is lying at the proper x-ray photon energy position when doing a quick graphical linear interpolation between the Cu K-alpha and the Sn K-alpha. The energy scale at your diagram is a bit confusing.

Also the intensity ratio of Cu K-beta/Cu K-alpha(1+2) is roughly in the order of the known value of 0,13*).

This value also holds for Zn. So if Zn is present in your sample, you should actually see a small peak at 9,57keV as Dirk already mentioned.

But Dirk Luetzenkirchen-Hecht , should not the buit-in software correction consider the beta line(s) when estimating the concentrations?

Anna Karakasi you may scan high purity iron. Fe K-beta is at about 7,06keV; and Ni K-alpha is about 7,47keV. Your system may find Ni.

or

you may scan Zn; Zn K-beta is at 9,57keV; and Ge K-alpha is at about 9,88keV. Your system may find Ge.

Good luck

*) e.g. N.A. Dyson; X-Rays in atomic and nuclear physics

@Gerhard Martens, indeed, our Edx software automatically uses all peaks of identified element for quantification. So the intensity of the K- beta would be automatically subtracted from the zinc at the same position, reducing the amount of detected Zn...