Development of high current Bi and Au beams for the synchrotron operation at the GSI accelerator facility

In this work, the latest results of developing high current ion beams of Au and Bi at GSI facility are described. The difficulties in the production of required charge state in vacuum arc discharge ion sources using the pure materials in the cathodes are discussed. As a possible solution, admix of a small amount of more refractory metal to the cathode material is considered. As a significant result, a dramatic improvement in the production of high charge state Bi ions using the mixed Bi-Cu cathodes (with 8%-15% of Cu admixed) compared to pure Bi cathodes is presented. The preliminary results of investigation of the material structure of Bi-Cu cathodes are discussed. As a next step, it is planned to test the composition of Au with Pd, Zr, and Fe as cathode materials. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3670743]