Physics and engineering design of 400 keV H- accelerator for negative ion based neutral beam injection system in China

A research project of the CFETR Negative ion-based Neutral Beam Injection (NNBI) prototype has be started in China. The objectives of the CFETR NNBI prototype are to produce a negative hydrogen ion beam of >20 A up to 400 keV for 3600 s and to attain a neutralization efficiency of >50%. In order to identify and optimize the design of the negative ion accelerator, a self-consistent model has been developed to consider all key physics and engineering issues (electric and magnetic field, background gas flow, beam optics, beam-gas interaction, secondary particles trajectories, power deposition on grids, heat removal design, and mounting pattern). This paper presents the primary results by applying the self-consistent model to the current design of the 400 keV H- accelerator of the CFETR NNBI prototype.