Status report on project Hercules

Project Hercules is a project to improve ignitron switches which will then be used on the upgrade of Lawrence Livermore's Nova Laser for its inertial confinement fusion program. The goals of Hercules are to lifetime-test (up to 10000 shots) prototype ignitrons or other switches with the required Nova current and Coulomb parameters (300 kA, 200 C), recommend design changes, and retest the second-generation switches. The design and construction of the test circuit and necessary diagnostics are described. The details of the design and construction of a 0.5 MJ electrolytic capacitor bank and a semiautomatic diagnostic/control system are described. The required test run data include peak current and corresponding tube voltage for every shot, entire current and voltage waveforms every few shots, and ignitor resistance values every few shots. In addition, the conversion of a 120 kW, 12 kV constant voltage supply to an 8 A constant current supply with the use of six SCRs and a commercial control board is described.<
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