X-ray fluorescence analytical signal of elements with small atomic numbers as a function of the energy of primary photons

Resumo

The dependence of the intensity of X-ray fluorescence on the energy of photons exciting X-ray radiation is considered. For elements with small atomic numbers, the direct ionization of atoms, the major process for the majority of elements of the Periodic Table, is the main only at low energies of primary photons. With the growth of photon energy, the intensity of fluorescence due to photo and Auger electrons arising in the irradiated material increases. This component at certain energy becomes predominant. The further increase in the energy of primary photons leads to the suppression of the ionization of atoms by recoil electron arising in the incoherent (Compton) scattering of primary radiation. The effects of the energy of primary photons on the intensity of X-ray fluorescence for the studied processes differ significantly. The depth of these effects determines their contributions to the formation of the analytical signal. Study of the influence of excitation conditions allows the analyst to intelligently solve problems of the optimization of the X-ray fluorescence determination of elements with small atomic numbers.