Formation of intense focused ion and atomic beams

Series of injectors of focused neutralized ion and atomic beams with beam energy ranging from 5 to 40 keV, equivalent beam current of 1–20 A, angular divergence of beam ∼10−2 rad, equivalent current density in focus of beam more than 1 A/cm2, pulse duration of 0.1–100 ms is developed in Budker Institute of Nuclear Physics. A specific approach to the formation of high brightness ion beams is used in these injectors. The low transverse ion temperature of the plasma emitter is achieved by the use of plasma emitter formed by the collisionlessly expanding plasma jet. Ion beams are extracted from the plasma emitter by precise multi-aperture four-electrode ion optics systems. Two methods of beam focusing have been tested and successfully applied. In the first one the formed ion beam is focused by a magnetic lens and charge-exchanged into atoms in a pulse gas target. The second method is based on geometrical focusing of the beam by spherically bent electrodes of an ion optics system. To profit better use of the nonuniform plasma jet, the developed ion optics systems with geometrical beam focusing have gaps extending with radius which provides optimal beam formation from the enlarged surface.