M-shell ionization cross sections by proton impact on gold in the binary-encounter approximation

Estudo do espectro contínuo de raios-x induzido pela passagem de prótons de alguns MeV na matéria

“…Above the crossing point, the cross sections from the DHFS VDs are higher than the ones from the hydrogenic VDs. This behavior is in agreement with previous publications which covered the outer shells in di erent elements (Mukoyama, 2015(Mukoyama, , 2017(Mukoyama, , 2018.…”

“…Similar results have been obtained by Mukoyama (2015Mukoyama ( , 2017Mukoyama ( , 2018, who calculated the ionization cross sections in the BEA using VDs from hydrogenic, non-relativistic Roothaan-Hartree-Fock, and Dirac-Hartree-Slater wave functions, speci cally for for the M 5 subshell of gold (Mukoyama, 2015), the M 5 subshell of bismuth (Mukoyama, 2017), and the N 1 to N 7 subshells of bismuth (Mukoyama, 2018). Therefore, the present results agree with the e ect observed by Mukoyama and show that it remains valid for inner shells and when all shells are summed.…”

“…The BEA provides a DDCS for the ejection of an electron, from a given subshell of the target atom, and depends on the probability density function (PDF) of the speed of the electron, abbreviated as VD (velocity distribution) in the present work. It is therefore expected that the model used for the VD of the electrons must a ect the ionization DDCS in the BEA (Mukoyama, 2015(Mukoyama, , 2018. In this sense, the analytical expression of the 1s hydrogenic VD has been used in all the literature published previously to the present work for the calculation of the proton bremsstrahlung processes (Ishii, 2006).…”

“…As mentioned above, current calculations of the SEB DDCS rely on the ionization DDCS in the BEA and are usually performed assuming that the VD of the electrons is provided by the hydrogenic 1s wave function for all shells. This is an important approximation, since it was shown that the ionization DDCS in the BEA is sensitive to the choice of the VD model (Mukoyama, 2015(Mukoyama, , 2018. However, as the atomic number of the target element increases, the hydrogenic VD cannot account for the screening e ects in the outer shells, as the potential felt by the electrons is non Coulombian, and the relativistic e ects in the inner shells, which have higher values of the binding energy.…”