Progress on ITER prototype RF source and associated components

The High power ICRF source group of ITER-India is developing the ITER RF sources of output power level 2.5MW. The R&D phase of RF source development is completed using Diacrode and Tetrode in HPA3. The critical requirement of 1dB bandwidth over±1MHz about any central frequency, the output power of 1.5MW at VSWR 2.0 with all reflection phase angles as well as continuous wave operation up to 2000 sec over the frequency range of 36 MHz to 60 (55 for Tetrode) MHz were implemented during acceptance test. The delivery of the prototype RF source is due and procurement of all related components/sub-systems is underway. A versatile test facility is developed at the ITER-India laboratory containing in-house developed MW level transmission line components, mismatch transmission line system, high power dummy load, 3dB combiner, RF switches, SSPA, aux power supplies, etc. The developed wideband 3 dB combiner has been tested in power splitter configurations up to 1.5 MW and a voltage handling capability up to 22 kV (equivalent to 2.5 MW at VSWR 2.0) corresponding to an E field level of 2.6 kV/mm has been demonstrated. 10kW SSPA is being developed and tested with the frequency flatness requirement of the prototype RF source. The auxiliary power supply for filament, control grid, and screed grid for driver & final stage amplifiers of prototype RF source is developed with self-protection and tube protection circuits. The logic, hardware configuration, and required functions are well defined for the Local Control Unit for control, monitoring, and protection of the overall prototype RF source.