Development of a Multigap-Pseudospark Switch for the PFN of the SIS100/300 Kicker Magnet Pulse Generator

In Erlangen multigap Pseudospark switches are under development to meet the requirements of the pulse forming network (PFN) for the SIS100/300 kicker magnets which are: hold-off voltage > 70 kV, peak current of ~ 6 kA and pulse duration of up to 6 μs. In the final phase of development a three-gap switch will be used. As reliable triggering is a key problem, different trigger methods were investigated to provide reliable breakdown of the switch acceptable delay and jitter values. A novel scheme, the carbon nanotube trigger system provided very good switching characteristics, but still suffers from very low lifetime (< 10) due to erosion in the ambient gas atmosphere (D2 ~60 Pa) in the switch. A quite different and already widely tested system of the so-called highdielectric trigger module was significantly improved by using thicker dielectric discs (6 mm instead of 1 mm) and new materials. Such a high-dielectric trigger module with a flat and partly metallized electrode (e.g. by a grid or “ metal fingers”), and a dielectric in between is shown in Figure 1. “finger” contact “plate” contact high-dielectric material