Extraction studies on ECR ion sources

The production of radioactive ion beams in the SPIRAL project needs very efficient ion sources delivering beams with good optical properties. To improve these properties, the extraction conditions are studied. The last results obtained with a new extraction system are presented and compared to a numerical simulation. This comparison shows that the axial magnetic field influences the multicharged ion beam if the space charge during the acceleration. In order to decrease the axial magnetic field effect on the extraction zone, a parallel beam can be formed with a multi-electrode system. The first tests of this system are presented. (author)