Long term characteristics of repetitively operated high-current pulsed discharge gap switches

Characteristics of repetitively operated high-current discharge gap switches are investigated to develop long life, high-repetition pulsed power switches. The discharge gap switches of gap length 4 mm were filled with 0.6 atm of SF6, 3 atm of H2 to obtain the initial self breakdown voltage around 20 kV. The switches are of pulsed discharged at peak current about 9 kA, duration about 400 ns with repetition rate of about 3 Hz. The breakdown voltages (Vb) are recorded for 10,000 shots of discharge. From the experiment, we found that Vb and the scattering of Vb increases with increasing the shots when using SF6. In contrast Vb and the scattering of Vb are almost constant when using H2. After the shot the discharge gas are analyzed and found that new composites were produced when using SF6 where no new composite was observed when using H2 or N2 gas.