Generation of high charge state ions in vacuum arc ion sources by a "current jump" method

Abstract

Summary form only given. In our investigation of ion charge state distributions (CSD) in vacuum arc plasmas, good correlation between increase in arc operating voltage and mean ion charge state has been established (Oks et al., 1996). Therefore, to increase the mean charge state of a vacuum arc plasma, it is necessary to find ways to increase the arc operating voltage. The voltage can be increased via transients associated with the arc current by means of which a rather high operation voltage can be established across the discharge gap. Experiments were performed both in Tomsk and Berkeley with the discharge system of a vacuum arc ion source. To effect a step current rise an additional power supply was connected to the usual vacuum arc supply. This power supply made it possible to increase the vacuum arc current up to 1 kA for several /spl mu/s. As a rule the current jump was produced after 100-200 /spl mu/s into the main discharge pulse when all principal parameters of the vacuum arc were already established. To measure the CSD a time-of-flight method was used.