Development of ion source with a washer gun for pulsed neutral beam injection.

A new type of economical neutral beam source has been developed by using a single washer gun, pulsed operation, and a simple electrode system. We replaced the conventional hot filaments for arc-discharge-type plasma formation with a single stainless-steel washer gun, eliminating the entire dc power supply for the filaments and the cooling system for the electrodes. Our initial experiments revealed successful beam extraction up to 10kV and 8.6A, based on spatial profile measurements of density and temperature in the plasma source. The system also shows the potential to control the beam profile by controlling the plasma parameters in the ion accumulation chamber.