Development of a 13-cm-Diameter Permanent-Magnets-Expanding Plasma Source Providing a Supersonic Ion Beam

A ~ 13-cm-inner-diameter permanent-magnets (PMs)-expanding plasma source for generation of a large diameter supersonic ion beam is developed and connected to a large volume diffusion chamber of 76 cm in diameter and 100 cm in length. The arrays of the PMs provide an expanding magnetic field of about 80 Gauss in the source tube and of about ten Gauss 30 cm downstream of the source exit. The radial measurements of ion energy distributions by a retarding field energy analyzer shows generation of a ~ 13-cm-diameter supersonic ion beam near the source exit.