Power correlation in an optimized ECR plasma for high ionized ions

The impact of the double frequency heating (DFH) physics on the performance of Electron Cyclotron Resonance Ion Sources (ECRIS) has been investigated by studying the correlation between the two RF-frequencies, injected into the plasma of an ECRIS operated in DFH mode by measuring extracted currents of highly charged Argon ions from the Frankfurt 14 GHz-ECRIS as a function of the relative sharing of the total injected power. In order to study the influence of the plasma physics, the effectivity of DFH as a function of the plasma–electron–densityand -energy, a second series of measurements has been carried out, where the ECRIS was run in an enhanced configuration with plasma parameters, where plasma–electron–density and -energy were close to values typical for a more performant (e.g. 18 GHz) source. The measurements demonstrate the positive impact of the DFH physics particularly for the creation of very high charge states also and in particular for high performing sources in modern accelerator installations.