Solid-state marx type circuit for the ISOLDE voltage target modulator

This paper describes a circuit topology proposed to replace the actual modulator circuit that supplies the 60 kV target voltage potential for the ion acceleration, at the ion source of the On-Line Isotope Mass Separator ISOLDE, located at the Proton-Synchrotron Booster PSB of the European Organisation for Nuclear Research CERN, the stability of which is critical for the mass resolution of the downstream separator. The proposed circuit uses two solid state switches, based on the Marx generator concept, to reduce the stress on the semiconductors, operating as a serial and parallel switch in order to fulfil the requirements of the target. The preliminary results of a 10 kV laboratory testing, using 1200 V IGBTs and capacitors in the two, ten stages, solid-state Marx generators are reported and discussed.