Magnesium based photocathode for back-lighted thyratron

Summary form only given. Optically triggered pseudospark switches, also called back-lighted thyratrons (BLTs), are high voltage (>;37 kV), high current (>;17 kA), glow-mode plasma switches, in which breakdown is initiated by photoemission from the switch cathode^1-4. Investigation of metal photocathodes under BLT-relevant conditions showed that magnesium is a promising cathode candidate for BLT with its relatively high quantum efficiency (up to 1.5×10^-5) compared to copper or molybdenum. We studied the switching characteristics of a BLT with Mg foil applied at the back surface of the cathode. The delay and jitter of the switch are at least three times shorter when Mg foil is present at the cathode. Reduction of the delay and jitter as a result of the presence of Mg foil at the switch cathode suggests even greater improvement of the switching characteristics can be achieved with the application of Mg cathode. In addition, the electron emission mechanisms effective during the discharge initiation in the switch that contribute to the reduction in delay and jitter are discussed.