Results of 10-Joule wire-burn test performed on 70 kV rail-gap crowbar protection system for high power klystrons and gyrotron

Pulsed and continuous high power microwave tubes need to be protected against arc faults within the tube. If the energy dumped in such arc fault is more than the critical crater energy of the tube, irreparable damage can occur. Modern switch mode powers supplies (SMPS) that are generally opted for the new systems store little energy and are capable of switching HV in few microseconds. So they do not need separate protection. However, when conventional power supplies feed high power microwave tubes a reliable crowbar protection system, tested separately to limit the energy, must be used to assure the tube safety. Initial testing and commissioning of two klystrons, TH2103D have been carried out at our Institute. Each of these klystrons is capable of delivering 500 kW at 3.7 GHz, to be used for non-inductive lower hybrid current drive (LHCD) In the Steady-State Superconducting Tokamak-1 (SST-1). Commissioning of the gyrotron VGA8000A19, for breakdown and electron cyclotron resonant heating (ECRH) experiments on Aditya tokamak, has also been carried out.