CIMAP, Caen
GANIL, Caen
One of the goals pursued by the people working on ion sources is to provide the highest beam intensity in the smallest emittance. As the computer power has increased so fast for the last years, it is possible nowadays to simulate with more accuracy the extraction of the ECR ion sources taking into account the several Physics processes involved in the beam creation. From the last chapter of the paper written by R. Leroy and coworkers [1], it has been shown experimentally that the intensity of a beam can be improved significantly by biasing the plasma electrode. The idea was to use the isolated plasma electrode as a 'biased disk'. We have calculated the influence on the extracted ion trajectories of this additional potential (from +3 V down to -100 V). The simulations have been computed for the MONO1000 and SUPERSHyPIE ion sources. All the simulations showed an increase of the brightness of the beam with more or less gain depending on the extraction voltage and the extraction conditions. A recent experiment performed on the MONO1000 ECRIS has confirmed the feasibility of this method: a gain of 40% in terms of emittance has been obtained on an 84Kr1+ beam.
[1] R. Leroy et al., Proceedings of the 12th International Workshop on ECR Ion Sources, April 25-27, 1995, RIKEN, Japan
