Ion-collision experiments with slow, very highly charged ions extracted from an electron-beam ion trap

Abstract

Highly charged Ar (up to 18+), Xe (up to 48+), and U (up to 71+) ions produced through electron-impact ionization and excitation in an electron-beam ion trap have efficiently been extracted from the trap, and mass and charge analyzed. Charge-state distributions for Ar and Xe ions following electron-impact ionization and excitation have been measured. Relative yields for the production of ${\mathrm{Ar}}^{16+}$ and ${\mathrm{Xe}}^{44+}$ ions have been deduced as a function of electron-beam energies. Ar K and Xe L x-ray emission following ${\mathrm{Ar}}^{17+}$, ${\mathrm{Ar}}^{18+}$ and ${\mathrm{Xe}}^{44+}$, ${\mathrm{Xe}}^{45+}$ and ${\mathrm{Xe}}^{48+}$ ion impact on a Cu surface was measured. The observed line positions demonstrate electron capture into high-n states and a fast radiative decay in the neutralization process at the surface.