Yields ofK-vacancy-bearing metastable states following foil excitation

Abstract
We have measured absolute yields of K x rays from the decay of heliumlike (1s2p)P23 and lithiumlike (1s2s2p)P524 states produced by the passage of 30-50-MeV beams of Si, S, and Cl through thin foils of C, Al, Ti, and Ni. The x-ray yields saturate for sufficiently thick foils at values which are strongly dependent on the foil material. This behavior is attributed to the dependence of the saturation K-vacancy-bearing fraction of the beam on target atomic number. A model based on the factorization of inner- and outer-shell processes is described and used to discuss the data.