X-RAY-PRODUCTION BY ELECTRON-EXCITATION, IONIZATION, AND CAPTURE FOR FQ+ (Q=1-9) IONS IN COLLISIONS WITH A HE GAS-TARGET

K x-ray transitions resulting from collisions between F projectiles, with charge states ranging from 1+ to 9+, and He atoms have been observed. Production mechanisms leading to projectile K x rays include K-shell electron excitation, single K-shell multiple L-shell vacancy production, and electron capture. The measured F K x-ray production cross sections range from 10-22 cm2 for low charge states to 10-17 cm2 for incident bare ions. Using calculated average fluorescence yields, the K-shell electron excitation, single K-shell, single K-shell + single L-shell, single K-shell + double L-shell ionization, and electron-capture cross sections have been determined. The measured ionization cross sections are found to decrease with the increase in projectile charge state, whereas single-K-shell electron-excitation cross sections increase with the increase in projectile charge state. © 1979 The American Physical Society.