Electron cyclotron resonance ion trap, a multicharged ion breeder/buncher

The basic mode of operation of an electron cyclotron resonance ion source is recalled, particularly when using such a device as an ion charge breeder for the production of radioactive ion beams suitable for acceleration (1+→n+conversion). A new mode of operation, Electron Cyclotron Resonance Ion Trap (ECRIT), permitting to trap and bunch the n+ ion beams is demonstrated. The principle of the ECRIT mode is explained. The charge breeder/buncher system is experimentally verified by the injection of a 400 nA Rb1+ ion beam leading to a 11.5 μA peak current of the Rb15+ ion beam extracted during the first ms. The temporal evolution of the cumulated particle transformation efficiency is measured in the case of Rb15+ and shows a 2.2% efficiency during the first 20 ms of the ECRIT extraction. The interest of the ECRIT mode is finally shown when used for the production of high-energy radioactive ion beams.