A power supply system for a 125 keV/250 keV neutral beam injector test stand based on negative ion sources

A design for a power supply system for the neutral beam injection (NBI) test stand of the large helical device (LHD) is presented. The acceleration power supply of −250 kV, 50 A is composed of three power supplies connected in series to deliver two intermediate outputs. It has a −40 kV power supply, a −90 kV power supply and a −120 kV power supply. A beamline and the major part of the power supply system for the NBI test stand were constructed in 1992. The −120 kV power supply was moved from Higashiyama to Toki in 1994. Another power supply of −40 kV will be added for −250 kV acceleration in the future. A brief outline of the control system of the NBI test stand is also presented.