L-subshell ionization studies in Au and Bi for 19F and 28Si large-ion bombardment.

Abstract

{ital L} x-ray production and subshell ionization cross sections of Au and Bi have been measured for the bombardment of {sup 19}F and {sup 28}Si ions in the energy range 30{endash}57 MeV and 36{endash}84 MeV, respectively. Comparison of the {ital L}{alpha} x-ray production cross sections of Au with the earlier data by Malhi and Gray [Phys. Rev. A {bold 44}, 7199 (1991)] shows reasonable agreement for {sup 19}F impact and their data are consistently higher for {sup 28}Si at all energies. The measured {ital L}{alpha} line energy shows a shift towards higher energy, which appears to be proportional to the square of the projectile atomic number at all impact energies. This shift suggests the presence of multiple ionization in the {ital L} and {ital M} shells with a simultaneous production of four {ital M} holes in Au at the impact energy of 3 MeVu{sup {minus}1} of {sup 28}Si. The {ital L}-subshell ionization cross sections obtained from the measured x-ray production cross sections have been compared with the semiclassical approximation and perturbed stationary state theory with energy loss, Coulomb deflection, and relativistic correction for the electron motion calculations, which show large deviations for the {ital L}{sub 1} subshell. The {ital L}{submore » 2}- and {ital L}{sub 3}-subshell ionization cross sections are underestimated by both the theories by a factor of 1.2{endash}4.0 for {sup 28}Si impact whereas for the {sup 19}F case there is reasonable agreement for the {ital L}{sub 3} cross section but the {ital L}{sub 2} cross section is underestimated by 20{endash}30{percent}. {copyright} {ital 1996 The American Physical Society.}« less