CONTROL SYSTEM FOR THE DIAGNOSTIC NEUTRAL BEAM INJECTOR FOR THE TCV TOKAMAK

The diagnostic Neutral Beam Injector (DNBI) for the TCV tokamak, Plasma Physics Institute, Lausanne, was developed and commissioned by the BINP team in 1999. The DNBI is capable of providing a beam of hydrogen atoms of 50 kV maximal energy, with an equivalent beam current of up to 1 A. The injector is equipped with all the power supply units needed for operation and for control, including a 50 kV, 2.5 A modulator and 10 kW, 4.6 MHz RF amplifier. The output beam can be extracted continuously over a 2 second period or as an ON/OFF modulated sequence with arbitrary pulse repetition frequency and minimal pulse/pause duration of 2 ms. An increased noise level looks like a normal condition for all subsystem operation. The control system of the DNBI is developed under the pressure of these specific conditions with increased noise. The system includes 8 DAC, up to 64 ADC channels and 64 channels of In/Out digital status control. It operates as a selfsufficient system with minimal data exchange with the global control system of the tokamak, so it becomes flexible to adopt arbitrary external control system.