Hannover 2003 – wissenschaftliches Programm

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A: Atomphysik

A 6: Ion-Molekülwechselwirkung

A 6.5: Vortrag

Montag, 24. März 2003, 17:30–17:45, F128

Electron Pickup and Neutralisation in Xenon Ion - Helium Gas Interactions — •Maria Sanchez-Vega, Ronnie Hoekstra, Klaus Jungmann, Lorenz Willmann, and Hans W. Wilschut — Kernfysisch Versneller Instituut, Groningen, The Netherlands

The stopping of highly charged ions in gases has been proposed as an effective technique for rapid thermalization of energetic secondary ion beams at radioactive isotope facilities. For further manipulation of the slow isotopes they must be obtained in a single low charge state, preferentially singly or doubly charged. In this connection the interactions of ions below 10% of the Bohr velocity with the host gas are of relevance, since in this region the cross sections for neutralization exceed those for stripping. We have employed a differentially pumped He interaction cell where target densities in the range up to 0.3 µg/cm² could be maintained. Xe⁵+ ions where obtained from an ECR source and accelerated at the KVI atomic physics beam facility up to 100 keV total energy. The intensities of the different resulting charge states were electrostatically analyzed. The neutral fraction was observed simultaneously on a microchannel plate detector. The neutral fraction increases with lower impact energies and exceeds 90% at 25 keV.