PLT and ISX neutral beam injectors

Six high power (40 keV--60 A) injection systems, four for PLT (Princeton Plasma Physics Laboratory) and two for ISX (Oak Ridge National Laboratory) tokamaks, have been developed, fabricated, and operated. Each injector delivers 750 kW (1000 kW) of H (D) neutral power to the tokamak plasma. An in-depth system parameter study has revealed unique features: high atomic yield (approximately 85%), improved ion optics due to a preacceleration technique, near steady-state operation (up to 500 msec), and a possible technique to control species yield. Routine operation includes high duty cycle (approximately 10%), long filament lifetime (several months), high arc efficiency, and the reliability necessary for application on a fusion device. The program status and injection parameters will be discussed.