L-shell X-ray production cross sections of selected lanthanoids by impact of ~7Li~(2+) ions with energies between 3.50 MeV and 5.25 MeV

摘要

L-shell X-ray production cross sections from the lanthanoid elements Ce, Nd, Sm, Eu, Gd, and Dy, induced by the impact of ~7Li~(2+) ions with energies in the range 3.50 MeV to 5.25 MeV (0.50 MeV/u to 07.75 MeV/u). were obtained experimentally in order to compare them with theoretical calculations from ECPSSR and related corrections, such as the electron capture by the incoming ion, multiple ionizations of higher shells, the United Atom refinement, and intra-shell coupling. Present results are compared to all previously published L X-ray production cross sections for ~7Li~(2+) ion impact. A universal behavior is found when the X-ray production cross sections are plotted as a function of the reduced velocity parameter ξ_L~R. Although an improvement in the overall comparison is attained after the ECPSSR theory is adjusted, there is still a need for further advances in the models, in particular an extension of the validity range (both in projectile atomic number and energy) of the intra-shell coupling correction.