Focusing of He+ beams using a compact electrostatic quadrupole lens system

A compact electrostatic quadrupole lens system has been developed, and experiments have been conducted to study transport and focusing of intense He+ beams with β=v/c=0.0029 and generalized perveance (Theory and Design of Charged Particle Beams, Wiley, New York, 1994) K=0.0013. Such beams are transported without any loss of beam particles and focused at a distance of about 0.6 m from the source with emittance growth less than a factor of about 1.8. This compact ESQ system has merits to satisfy a critical demand for developing intense He0 beams for alpha-particle diagnostics in fusion-relevant machines.