Ion source with high emission current density beam production

Summary form only given, as follows. An ion source for production of DC ion beams with high emission current density will be discussed. The source used a Penning discharge cell with permanent ceramic magnets optimized for high density plasma production. Using self-heated LaB/sub 6/ cathodes and a discharge voltage of /spl sim/80 V results in an increase of ion generation efficiency, reduced sputtering and cathodes lifetime increase up to hundreds of hours. Small holes on the axis of the cathodes are used for gas injection and for beam extraction along the magnetic field. Operating at a discharge current 0.8 A, the hollow cathode discharge increases the plasma concentration on the source axis and improves gas efficiency of hydrogen ion production up to 60% with proton content more than 60%. Conditions for long time noiseless operation, which are optimal for high brightness ion beam production have been found. This long-time ion source has operated stability in an accelerator used for material surface modification. Efficiency, g, of high current density j=O. 6 A/cm/sup 2/ divided to the full discharge power P=60 W, for this source is g=j/P=10 A/cm/sup 2/ kW. For other high efficient ion sources, g=0.2-0.05 A/cm/sup 2/ kW is typical.