Dear Yaseen Muhammad ,

the excitation energy of the electrons has to be larger than the x-ray photon energies of the equivatent x-ray emission lines, which in your case are below 20keV.

For example for Ag (Z=47) the Ag K-alpha ( ~22keV) and Ag K-beta line (~24,9keV) you have to excite the Ag K-shell (K 1S) electron having a binding energy of about 25,5 keV. Thus in this case the electron energy has to be larger than 25,5 keV.

For elements of atomic number Z being smaller than that of Ag (ZAg=47), you may also use that electron energy.

For elements having much smaller atomic number you may go for lower excitation energy. So it depends on the maximum of the atomic numbers you have got in your sample...

For the detection of elements having far larger atomic numbers you may go for the excitation of the L shell(s), which have quite lower excitation/binding energies that of the K-shell electrons. The L-lines show up at energies much lower than their K-line equivalents.

For the emission lines and excitation/binding energies (edge energy) of the elements please have a look for example at the 'x-ray data booklet'...

x-ray data booklet; x-ray emission lines;

http://xdb.lbl.gov/Section1/Sec_1-2.html

click on : Table 1-2 (pdf-format) ‚

x-ray data booklet; binding energies:

https://xdb.lbl.gov/Section1/Sec_1-1.html

click on: (PDF version of this table) ‚

Final remark:

the correct writing of the energy unit of 'kilo electron volt' is [keV]

and not [Kev]...

Best regards

G.M.

In addition to theoretical answer by Gerhard Martens a practical advise: as a rule of thumb for good generation of X-rays beam energy should be at least 1.5 times higher than excitation energy of an element.

The electron energy used in EDX experiments for characterization of nano-compositees depends on several factors, including the composition and thickness of the sample, as well as the desired spatial resolution and sensitivity of the analysis. Tpically, the electron energy used for EDX analysis can range from a few keV to several tens of keV. In general, lower electron energies are used for samples with lower atomic numbers and thinner samples, while higher electron energies are used for samples wth higher atomic numbers and thicker samples. It is important to optimize the electron energy for each specific sample ensure accurate and reliable EDX results. Maybe, the article below may be of use to you.

Article X-ray-Based Spectroscopic Techniques for Characterization of...