Operation of JT-60 NBI and NBI system for JT-60 upgrade

The JT-60 JAERI (Japan Atomic Energy Research Institute) Tokamak-60 neutral beam injector (NBI) has been successfully operated for three years, delivering a neutral beam power of 20 MW at a beam energy of 75 keV. The helium-beam injection into JT-60 was performed to investigate exhaustion of fusion alpha particles from the plasma. The helium-ion beam current extracted from ion sources was 40-45 A at an energy of 31 keV. The injection power was about 0.4 MW. In the helium-beam operation, the helium gas in the beamline chamber was pumped out by a condensed SF/sub 6/ gas cryosorption pump. The JT-60 neutral beam injector will be modified to inject a 120-keV deuterium beam into the JT-60 upgrade, which will start to operate at the beginning of 1991.<
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