The Frankfurt MAXEBIS setup for advanced charge breeding experiments

The demand of exotic ions of higher charge states for the injection into an accelerator has driven the development of the charge breeding method. Existing facilities such as REX-ISOLDE or ISAC (TRIUMF) are already using a charge-state booster for the post acceleration of radioactive ions. Planned facilities such as MAFF, SPES, SPIRAL II, and EURISOL have identified the need for a breeding system because of the demand for highly charged ions for low-energy experiments and because of the available budget. Therefore, the exploration and optimization of existing charge-state breeders is mandatory and is supported by the I3-EURONS project. Some tasks of the joint research activity “charge breeding” are experiments with the Frankfurt MAXEBIS setup, which has been modified within the past years toward high current electron beam and external injection of alkaline ions by a surface ionization source. The electron gun, the inner electrode structure, and the collector of the MAXEBIS have been modified. The full MAXEBIS setup has been moved from Frankfurt to GSI, where the charge breeding measurements will be done. In addition the MAXEBIS will deliver highly charged ions for tests of the cooler Penning trap of the GSI Heavy Ion Trap project HITRAP. The setup, tests, and the planned breeding experiments will be discussed.