Measurement on the $M$-shell x-ray production cross sections are reported for Pb and Bi induced by the highly charged F (only on Pb) and C ions (on both). The energy of the incident ions was varied between 20 and $102\mathrm{MeV}$. We have derived the absolute cross sections for $M\alpha \beta$ and $M\gamma$ lines as well as the total $M$ x-ray cross sections. The measured cross sections are compared with available theoretical calculations, namely, the ECPSSR based on the perturbed-stationary state approximation including the effects due to the increased binding energy, Coulomb deflection $\left(C\right)$, energy-loss $\left(E\right)$, and relativistic $\left(R\right)$ wave function. The energy shifts and the intensity ratios of $M\alpha \beta$ and $M\gamma$ lines are shown to depend on the projectile atomic number. The $M\gamma$ x-ray cross sections are unusually higher compared to the ECPSSR prediction that is primarily attributed to a dramatic enhancement in the $M_3$-subshell fluorescence yield owing to multiple vacancies in $N$ subshells. This enhancement has been quantified and it is shown that the enhancement depends on the projectile atomic number. In addition we have derived the x-ray cross section arising due to $M\text{−}K$-shell electron transfer from a study of a charge state dependence of $M$-shell x-ray yields.

• Received 6 August 2005

DOI:https://doi.org/10.1103/PhysRevA.73.032712