• O. A. Tarvainen, S. S. Kurennoy
  LANL, Los Alamos, New Mexico

A conceptual design for a negative ion source based on electron cyclotron resonance plasma heating and surface ionization is presented. The plasma chamber of the source is an rf-cavity designed for TE111 eigenmode at 2.45 GHz. The desired mode is excited with a loop-antenna. The ionization process takes place on a cesiated surface of a biased converter electrode (cathode) sputtered by plasma ions. The ion beam is 'self-extracted' through the plasma. The magnetic field of the source is optimized for both, plasma generation by ECR heating, and beam extraction. The source can be used for production of negative ions ranging from hydrogen to heavy ions. The potential users for the source concept range from large scale accelerator facilities, utilizing H^- ion beams, to dc tandem accelerators for heavy ions. The benefits of the source concept compared to widely used filament- and inductively coupled rf-driven sputter-type sources are the lack of consumable parts and low neutral gas pressure minimizing the stripping losses of negative ions. In this article we will focus on the H^- production scenarios with the source. The benefits and drawbacks of higher frequency operations are discussed.