Charge voltage, trigger voltage and gas dielectric effects on multi-channel closing of a Russian multi gap switch

The Z machine at Sandia National Laboratories is equipped with 30 spark gaps in each of its 36 Marx banks. It is crucial that each switch operate flawlessly to obtain the desired pulse and avoid pre fires. A Russian Multi Gap Switch (MGS) is being tested for several possible advantages over current technology. Air is the primary dielectric gas used in the MGS instead of SF₆, which is used in the existing spark gap system. It is triggered at low trigger voltages with a commercial trigger generator reducing wear on electrodes. Most interestingly, it is designed to produce multi-channels when fired, reducing the firing inductance and increasing pulse rise time. To analyze channel firing properties, the Russian MGS is fixed in single stage Marx, similar to the arrangement in the Z machine. Capacitor charge voltage and switch trigger voltage is varied over typical operating conditions to determine how these factors effect the closing of the MGS. Air, SF₆, SF₆-air, and SF₆-argon mixtures are used to study gas dielectric effects on MGS multi-channeling. The switch´s opaque casing is replaced with clear casing so a very fast camera may document switch closing characteristics with an emphasis on multi-channel operation. The MGS is adapted so it may be opened with conventional tools. Results from all permutations of variables are obtained and correlated to multi-channeling of the switch. A complete description of the MGS is also presented.