Laser Triggered Gas Switches Utilizing Beam Transport Through 1 MΩ-cm Deionized Water

We report on the successful attempts to trigger high voltage pressurized gas switches by utilizing beam transport through 1 MΩ-cm deionized water. The wavelength of the laser radiation was 532 nm. We have investigated Nd:YAG laser triggering of a 6 MV, SF₆ insulated gas switch for a range of laser and switch parameters. Laser wavelength of 532 nm with nominal pulse lengths of 10 ns full width half maximum (FWHM) were used to trigger the switch. The laser beam was transported through 67 cm-long cell of 1 MOmega-cm deionized water constructed with anti reflection UV grade fused silica windows. The laser beam was then focused to form a breakdown arc in the gas between switch electrodes. Less than 10 ns jitter in the operation of the switch was obtained for laser pulse energies of between 80-110 mJ. Breakdown arcs more than 35 mm-long were produced by using a 70 cm focusing optic.