A Fast Multichannel Crowbar Switch

A field distortion switch is used for crowbar operation. It consists of two flat main electrodes with a metal sheet between them, dividing the switch into two gaps. Taking special precautions, it was possible with a single trigger source to break down both gaps. Reliable crowbar performance is possible with solid as well as with gas insulation. In both cases multichannel breakdown is achieved. Up to 200 breakdown channels have been observed with solid and up to 10 with gas insulation. Tests have been carried out using capacitor banks at voltages between 20 and 60 kV and with frequencies up to 250 kHz. Maximum currents varied between 20 and 300 kA. The larger current and voltage values were used with solid dielectric crowbar switches. The jitter time of the switching device is less than 10 ns, the major part being due to the trigger generator.