Enhancing the performances of ECR ion sources

The performances of ECR ion sources can be enhanced in the spatial domain by tailoring the central magnetic field so that it is uniformly distributed over a large plasma volume and is of magnitude so as to be in resonance with single frequency microwave radiation. Analogously, the performances of conventional minimum-B ECR ion sources can be enhanced in the frequency domain by injecting multiple discrete frequency or broadband microwave radiation into their plasma volumes. In this report, examples of both the spatial-and frequency-domain techniques will be given. For example, the design aspects of an all permanent-magnet “volume-type” (spatial-domain) ECR ion source will be described and the effects of injecting multiple frequencies (frequency-domain) on the charge-state-distributions extracted from a conventional minimum-B ECR ion source will be presented