Application of a self-breakdown hydrogen spark gap switch on high power pulse modulator

Hydrogen has the best recovery property compared to other gases such as N2 and SF6. Therefore, it has a potential application on the multipulse or high repetitive pulse modulator. This paper introduced a high pressure hydrogen gas switch with two cylindrical structures. The stress of the switch under high pressure was analyzed theoretically, and the hydrogen gas switch was hydrostatically tested with pressure up to 30 atm. Such a switch was employed on a high power pulse modulator using water as the dielectric of pulse forming line. At the switch breakdown voltage of 520 kV and the pressure of hydrogen 12 atm, 230 kV, 31 kA, and 60 ns pulse width electron beams were obtained at the field emission diode. Furthermore, when the switch was filled with different gases such as H2, N2, and SF6, the rise times of diode voltage of modulator had been compared at the gas breakdown voltage 400 kV. The results showed that the rise times of diode voltage were reduced obviously when hydrogen was used as the dielectric of spark gap switch.