NSCL, East Lansing, Michigan
We designed and constructed a new, completely superconducting Electron Cyclotron Resonance Ion Source (ECRIS) called SuSI, operating at 18+14.5 GHz microwave frequencies. Besides the increased intensities, this ECRIS was designed with several adjustable parameters in order to allow the optimization of the extracted ion beam brightness: magnetic field (axial magnetic peak position and magnitude, radial magnetic field magnitude), plasma chamber length, bias disc position and voltage, extraction electrode (puller) position and voltage and bias voltage on the beamline. The accelerated beam intensity out of the Coupled Cyclotron Facility is determined not only by the available ion beam intensity from the ECRIS but also by emittance of the ion beam and its proper match to the cyclotron acceptance. The emittance of the extracted ions was measured with an Allison-type emittance scanner. We will present the general performance of SuSI as well as results from beam studies on the influence of the tunable ion source parameters on the intensity and emittance of the extracted ion beams. Emphasis will be on the results for the medium charge states needed for the CCF operation.
