Multiple Inner-Shell Ionization of Aluminum by High-Velocity Medium-ZBeams

High-resolution studies of aluminum $K\alpha$ x rays produced by O, F, and Cl beams at beams energies ≳ 1 MeV/amu have been performed with a crystal spectrometer. Fluorescence yields are calculated for the various single $K$-shell, multiple $L$-shell vacancy configurations. A simple model of the ionization process has been assumed that allows determination of average $2s$ and $2p$ ionization probabilities from the experimental x-ray yields using the calculated fluorescence yields.