Development of the JT-60SA Neutral Beam Injectors

This paper describes the development of the neutral beam (NB) systems on JT‐60SA, where 30–34 MW D0 beams are required to be injected for 100 s. A 30 s operation of the NB injectors suggests that existing beamline components and positive ion sources on JT‐60U can be reused without the modifications on JT‐60 SA. The JT‐60 negative ion source was modified to improve the voltage holding capability, which leads to a successful acceleration of 2.8 A H− ion beam up to 500 keV of the rated acceleration energy for JT‐60SA.