Elevated ion charge states in vacuum arc plasmas in a magnetic field

Abstract

We report on measurements of the charge state distributions of ions formed in a vacuum arc plasma in a magnetic field. A vacuum arc ion source was used for plasma formation and ion beam extraction, and the charge state spectra were investigated using both magnetic and time-of-flight charge state diagnostics. We find that the charge states of all of the metal species investigated are significantly increased by a magnetic field of up to 6 kG. New high ion charge states are created, and the mean of the charge state distribution is increased by about 30% at 3.75 kG and 50% at 6 kG. The results are important fundamentally as well as being of relevance to vacuum arc ion source applications such as ion implantation and accelerator injection.