Multigap pseudospark switches for high voltage applications

The design of the pulse forming network (PFN) for the injection/extraction kicker magnet system of the future heavy ion synchrotron accelerator complex SIS100/300 at the Gesellschaft fuer Schwerionenforschung (GSI) requires an high-voltage switch, that can handle an hold-off voltage up to 70 kV, peak currents up to 6 kA and pulse durations up to 7 mu s. It is planned to use instead of commercially available high-voltage thyratrons multigap pseudospark switches. In this paper the reported experimental data have been obtained by using a prototype two-gap pseudospark switch with hold-off voltages up to 30 M The long-term goal of the development is to construct a multigap pseudospark switch, which can handle the specifications listed before. The emphasis of the actual experiments is directed to the problems correlated with the triggering of such a multigap systems. Two trigger methods have been studied, the so-called high-dielectric trigger (HDT), which already has proven its long term capability, and a novel system, based upon the electron emission of carbon nanotubes (CNT), which is actually more of principle interest. It still suffers from an insufficient small lifetime of 104 discharges. For both trigger units and for the first gap the measured delay and jitter vary from 50 to 60 ns and 15 to 30 ns, respectively. For the second gap delay and jitter increase up to 200 and 45 ns, respectively.