Helicon Plasma Generator-Assisted Negative Ion Source Project at Los Alamos Neutron Science Center

Helicon plasma generators are widely used for plasma processing applications due to their long life-time and capability of creating high-density plasmas efficiently. The aim of the helicon plasma generator-assisted negative ion source project at Los Alamos Neutron Science Center (LANSCE) is to use these features for producing intense beams of H- ions. Our development work builds upon pioneering experiments previously conducted at Lawrence Berkeley National Laboratory (LBNL) with a 2.45 GHz electron cyclotron resonance plasma generator. In the new approach a helicon plasma generator is used as a plasma cathode injecting electrons into a multi-cusp H- ion source. The secondary source can be operated without filaments or any other consumable parts and, consequently, the life-time of the ion source can be extended significantly. The development of the ion source is aimed to meet the beam production goals of the LANSCE 800 MeV linear accelerator refurbishment project i.e. 20 mA of H- beam with normalized area emittance (95 % of the beam) less than 1.1 π·mm·mrad and a duty factor of 12 %. The operation principle of the source, the test stand design and the status of the development work will be presented in this article