M-subshell x-ray production cross sections of Au induced by highly charged F, C, and Li ions and protons: A large enhancement in theM3fluorescence yield

Abstract

M-subshell x-ray production cross sections are measured for Au, induced by F ions in the energy range of 20 to 102 MeV. For a comparative study the measurements are also carried out for protons, He, Li, C ions at a few energies. We have derived the absolute cross sections for $M\ensuremath{\alpha}\ensuremath{\beta}$ and $M\ensuremath{\gamma}$ x rays as well as the total M x-ray cross sections. The intensity ratios, $I(\ensuremath{\gamma})/I(\ensuremath{\alpha}\ensuremath{\beta}),$ of the $M(\ensuremath{\gamma})$ and $M(\ensuremath{\alpha}\ensuremath{\beta}),$ as well as the energy shifts of these lines signifying multiple vacancies in outer shells have also been studied as a function of projectile atomic number. The measured cross sections are compared with available theoretical calculations, namely, the ECPSSR based on the perturbed stationary state (PSS) approximation including the effects due to the increased binding energy, Coulomb deflection (C), energy loss (E), and relativistic (R) wave function. In case of the $M\ensuremath{\gamma}$ the measured cross sections are much higher compared to the ECPSSR prediction which is attributed to a dramatic enhancement in the ${M}_{3}$-subshell fluorescence yield owing to multiple vacancies in N subshells. The enhancement strongly depends on the projectile atomic number.