KEK Multicusp Negative Hydrogen Ion Source

A surface plasma type multicusp H- ion source has been developed at KEK. Directly heated lanthan hexaboride (LaB6) filaments have been tested recently. Any serious damages have not been seen after the operation for more than 1,000 hours at the arc current of 20 -25 A and during the experiment, the H- ion beam of about 20 mA has been stably extracted. Increasing the arc current to 45 A - 50 A with using large size LaB6 filaments, we could obtain the H- beam current of 40 mA.