INITIAL RESULTS OF THE 2.45 GHZ EXCITATION OF THE SUPERCONDUCTING ECRION-SOURCE IN ITS HIGH-B MODE

The ''frequency squared scaling'' law, relied upon to enhance the prod uction of high charge state ions from electron cyclotron resonance (EC R) ion sources, indicates that low frequencies of operation may not be viable for production of high ion densities, and hence for the produc tion of high charge state ions. The superconducting electron cyclotron resonance ion source (SCECR) at the National Superconducting Cyclotro n Laboratory is a fully superconducting, hexapole stabilized tandem mi rror ECR ion source with a multimode microwave cavity. When operated a t its optimized high magnetic field (high-B) mode at 6.4 GHz, the high charge state current output of the SCECR approaches all existing ECR ion sources, including higher frequency ECR ion sources (ECRIS). In th is study, the SCECR is operated at 2.45 GHz in its high-B mode that is scaled down for that frequency of operation. Initial results with oxy gen and argon ion production at 2.45 GHz are presented. It is demonstr ated that the SCECR can produce a plasma from which multiply charged i ons of up to O7+ and Ar13+ can be extracted with ion current intensiti es comparable to several higher frequency ECRIS. This study concludes that 2.45 GHz is indeed a viable frequency for production of moderate intensities of multiply charged ions. This may lead to a simpler, and more cost effective microwave apparatus, with a less demanding magneti c field configuration. (C) 1995 American Institute of Physics.