New 14 GHz Electron-Cyclotron-Resonance Ion Source (ECRIS) for the Heavy Ion Accelerator Facility ATLAS

摘要

A new 14 GHz Electron-Cyclotron-Resonance Ion Source (ECRIS) has been designed and built over the last two years. The source, which is a modification of the AECR at Berkeley, incorporates the latest results from ECR developments to produce intense beams of highly charged ions, i.e. an improved magnetic confinement of the plasma electrons. The aluminum plasma chamber and extraction electrode as well as a biased disk on axis at the microwave injection side donate additional electrons to the plasma, making use of the large secondary electron yield from aluminum oxide. The source will be capable of ECR plasma heating using two different frequencies simultaneously to increase the electron energy gain for the production of high charge states. To be able to deliver usable intensities of the heaviest ion beams, the design will also allow axial access for metal evaporation ovens and solid material samples using the plasma sputtering technique. The main design goal is to produce several e(mu)A of at least (sup 238)U(sup 34+) in order to accelerate the beam to coulomb-barrier energies without further stripping. First charge state distributions for (sup 16)0 and (sup 40)Ar have been measured.