Compact output switch for megavolt e-beam accelerator

A compact output switch for a water pulse forming line(PFL) ebeam accelerator was designed. The accelerator is of the helical coaxial PFL type, having impedance of 9 Ω, and charging voltage 1.2 MV, and outputs 600 kV, 100 ns on matched load. The length of PFL is 1.1 m, and diameter less than 35 cm. The output switch is of the simple self-breaking gas type, designed following these principles: (1) it’s field enhancement factor is 1.4, which makes it possible to have a near linear curve for SF6’s voltage-pressure curve; (2) field within the gap is 300 kV/cm, 3 times stronger than that along the insulator, which prevents surface flashover; (3) field at triple points is controlled within 30 kV/cm; (4) the volume of switch is minimized to enhance its mechanical strength. The lengh of switc