Intense and Small Emittance Hydrogen Ion Beam Formation by BPD Ion Source

Abstract

An ion source of original concept, named "BPD Ion Source" is described, in which the source plasma is produced by an electron beam-plasma discharge. A hydrogen ion beam of 120 rnA can be continuously extracted from the plasma in the direction of the electron beam at an extraction voltage of 30 kV through a single circular aperture of 8 mm dia. located at the bottom of the discharge chamber. The current density has reached 239 mA/cm 2 • The hot electrons contained in the source plasma facilitate the extraction of this intense ion beam. The normalized emittance of this source was observed to be 9.4 x 10-7 m-rad with 100 rnA beam extraction. The abundance ratio of the beam ion species and other characteristics are described and a discussion is presented on the possibility of scaling up for purposes of practical application.