MEVVA ion source for uranium high current operation at the GSI accelerator facility

Abstract

A high particle current is needed to fill the synchrotron (SIS) at GSI to its space charge limit. The high current injector only accepts ions with a mass to charge ratio up to 65 with a space charge limit of the RFQ of 0.25 /spl times/ A//spl zeta/[mA] where A//spl zeta/ is the mass to charge ratio in atomic units. Thus the design ion for accelerator reasons is U/sup 4+/ with a space charge limit of 15 emA at the front end of the accelerator. For the production of high currents of metallic ions in pulsed operation a metal vapor vacuum arc ion source (MEVVA) is used. For accelerator operation the ion source has to provide a stable beam and has to run with high reliability over a long period of time. The results of a long term operation of the source at the high current injector of GSI are presented here revealing plasma parameters, the long term behaviour of beam current, transmission along the low energy beam transport section, lifetime and availability of the ion source.