Charge sensitive evaluated ion and electron energy distributions of a vacuum arc plasma

A metal vapor vacuum arc type ion source has been developed for the high current injector at the GSI accelerator facility for the production of high charge state uranium beams. This ion source provides a high intensity ion beam with a fraction of fourfold charged uranium ions up to 67% for injection into the linear accelerator. As part of the ion source development the ion and electron energy distributions have been measured with an electrostatic cylinder spectrometer device which discriminates charged particles with different energy to charge ratios. This allows a charge sensitive evaluation of ion energy distribution. Energy distributions have been measured for various discharge parameters, i.e., arc current, magnetic flux density, and cathode materials. Some important plasma parameters can be derived from these measurements: charge resolved ion energy distributions, mean electron energy and temperature, and the anode drop which in all support the development of a model of a vacuum arc plasma consisting of high charge states.