Study ofL-subshell ionization of Sm by protons: 0.3-2.0 MeV

Abstract

The $L$-subshell ionization processes in Sm for proton bombardment over the energy range 0.3-2.0 MeV were studied using a thin Sm target (15.0 ${\mathrm{\ensuremath{\mu}}\mathrm{g}/\mathrm{c}\mathrm{m}}^{2}$). The total $L$-shell x-ray cross section and x-ray cross sections for the transitions $\mathrm{Ll}$, $L{\ensuremath{\alpha}}_{1,2}$, $L{\ensuremath{\gamma}}_{1}$, and $L{\ensuremath{\gamma}}_{2,3}$ were determined at each proton energy. Calculations for the total $L$-shell x-ray and ionization cross sections and $L$-subshell ionization cross sections were performed for the non-relativistic plane-wave born approximation (PWBA), constrained-binary-encounter approximation (CBEA), and binary-encounter approximation (BEA). Comparisons of the theoretical predictions are made to the experimental values for the total $L$ x-ray production cross section, total $L$-shell ionization cross section, relative intensities of the $\frac{L{\ensuremath{\alpha}}_{1,2}}{\mathrm{Ll}}$, $\frac{L{\ensuremath{\alpha}}_{1,2}}{L{\ensuremath{\gamma}}_{1}}$, $\frac{L{\ensuremath{\alpha}}_{1,2}}{L{\ensuremath{\gamma}}_{2,3}}$, and $\frac{L{\ensuremath{\gamma}}_{1}}{L{\ensuremath{\gamma}}_{2,3}}$ ratios, and the x-ray production cross sections for the $L{\ensuremath{\alpha}}_{1,2}$, $L{\ensuremath{\gamma}}_{2,3}$ and $L{\ensuremath{\gamma}}_{1}$ transitions. The results of this work show that the nonrelativistic PWBA theory is in reasonable agreement with the ${L}_{I}$-subshell processes measured in Sm for protons. The CBEA does not predict the appropriate structure observed in the ${L}_{I}$ subshell. The BEA calculations show that there are major differences between the data for Sm and the predictions of that theory.