Results and interpretation of high frequency experiments at 28 GHz in ECR ion sources, future prospects

For the needs of future heavy ion accelerators, electron cyclotron resonance ion sources (ECRISs) should be able to deliver higher intensities and higher charge states. The $\text{1e}$ mA level intensity has already been reached by room temperature ECRIS for medium charge states of light elements $({\mathrm{O}}^{\text{6+}},$ ${\mathrm{Ar}}^{\text{8+}}\mathrm{).}$ However, such level of intensity for heavy elements (like ${\mathrm{Pb}}^{\text{27+}}$ for CERN/LHC and GSI) requires more powerful ECRIS with higher electron densities (up to ${10}^{13} {\mathrm{cm}}^{\text{−3}}\mathrm{).}$ On the other hand, an optimized magnetic configuration system has to be used in order to obtain the suitable compromise between the electron confinement and the high flux ion losses. Before the design of the future “high intensity ECRIS,” experiments have been performed with the superconducting SERSE source both at 18 and 28 GHz. After an overview of major results recently obtained, some scaling laws will be presented. Our results show that much larger intensities and charges can be reached with ECRIS. Then, we will show how the next ECRIS generation will look like, based on the scaling laws derived in the above-mentioned experiments.