Long life radio frequency surface plasma source

The development of H- ion sources with highest performance is essential for the success of the next generation of high power proton accelerators. Project X at Fermilab needs a CW H- Ion Source that satisfies demanding performance specifications: 10 mA CW beam current with normalized transverse rms emittance 0.2 mm-mr, fast chopping capability, fast intensity variation, and high availability. Many other new accelerator projects need CW and pulsed H- beams with performance exceeding those achieved today. Currently, no H- source satisfies these demands. In this project, we will develop novel modifications of H- source designs to satisfy these requirements based on a CW version of a Saddle Antenna (SA) RF Surface Plasma Source (SPS) that was developed for pulsed ORNL SNS operation. The unique plasma distribution generated by the saddle antenna allows more than 15 mA CW current with low power and corresponding longer lifetime. In addition, the new design will have improved electrode cooling using new materials, a new cesiation procedure with reduced cesium loss, and even longer lifetime through suppression of electrode sputtering and immunity to electrode shorting. The design will also be modified to be a long-life CW high-intensity proton source. The design of the advanced SPS with SA RF discharge will be developed including optimization of the H- emitter, cesiation, beam extraction, formation and transport. A prototype CW SA SPS will be developed and tested to validate the feasibility of producing the required parameters. Commercial Applications and Other Benefits: The applications of the new source to be developed in this project include proton drivers to be used for neutrino factories, muon colliders, spallation neutron sources, and accelerator-driven subcritical reactors. The source is an upgrade path for many other existing and planned applications such as medical treatments (including hundreds of cyclotrons with external injection for isotope production and high current tandem accelerators for Boron Neutron Capture Therapy), and homeland defense using resonant gamma ray techniques to detect explosives and special nuclear materials.