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The superconducting, heavy ion synchrotron SIS100 is the core of the new FAIR facility at GSI, Darmstadt, Germany. Its unique design is dedicated to the acceleration of intermediate charge state heavy ions. Several new technical approaches assure the stabilization of the vacuum dynamics and the minimization of charge related beam loss. Beside high intensity heavy ions, SIS100 will accelerate all ions from Protons to Uranium, and in spite of the fact that superconducting magnets are used, SIS100 shall be as flexible in ramping and cycling as a normal conducting synchrotron.

The long-term goal of the described experiments is to construct multi-gap pseudospark switches, which can handle reliably the specifications 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). The PFN 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 µs. In this paper most of the reported experimental data have been obtained by using a two-gap prototype pseudospark switch with total hold-off voltage up to 30 kV. There are two major problems correlated with the development of such multi-gap systems. The first one concerns efficient and reliable triggering of switch for the overall switch lifetime. Two trigger systems have been studied, the so-called high-dielectric trigger (HDT), which already has proven its long term capability, and second, a novel system, based upon the electron emission from carbon nanotubes (CNT). The CNTtrigger still suffers from an insufficient small lifetime of 10 4 discharges. The second critical part concerns the instant breakdown initiation in the individual gaps, separated by a drift space. In the experiments with this prototype an active pre-ionization of the drift space was nor foreseen. For both trigger systems the measured delay and jitter in the first gap vary from 50 to 60 ns and 15 to 30 ns, respectively; corresponding the second gap has a delay and a jitter of up to 200 and 45 ns, respectively. interests include the field of high-power switches and electron beam technology, generation of EUV radiation, and the applications of plasmas and lasers in medicine and biology.

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