Heavy Ion Source Support Gas Mixing Experiments

Abstract

Experiments on mixing an easily ionized support gas with the primary ion source gas have produced large beam enhancements for high charge state light ions (masses ? 20). In the Oak Ridge Isochronous Cyclotron (ORIC), the beam increase has been a factor of 5 or greater, depending on ion species and charge state. Approximately 0.1 cc/min of the easily ionized support gas (argon, krypton, or xenon) is supplied to the ion source through a separate gas line and the primary gas flow is reduced by ? 30%. The proposed mechanism for increased intensity is as follows: The heavier support gas ionizes readily to a higher charge state, providing increased cathode heating. The increased heating permits a reduction in primary gas flow (lower pressure) and the subsequent beam increase.