Comparison ofK-shell ionization cross sections of Si in solid and gas targets forFq++ Si collisions (q=4−9) at 1 and 2 MeV/amu

The authors determine $K$ x-ray production cross sections and $K$-shell fluorescence yields in solid Si and gaseous Si${\mathrm{H}}_4$ as a function of incident-projectile charge state for a F beam at 1 and 2 MeV/amu. Discrepancies between solid- and gas-target results are observed in both the x-ray production cross section and fluorescence yield. It is found, however, that the ionization cross section (x-ray production cross section divided by fluorescence yield) is independent of target physical state for each incident-projectile charge state.