Design of an electrostatic magnetic quadrupole accelerator

Abstract

A new type of electrostatic acceleration system, electrostatic magnetic quadrupole (ESMQ) acceleration system, is proposed for efficient acceleration of negative ion beams. In this system, permanent magnets are buried in the acceleration electrodes so as to produce a quadrupole magnetic field in the electrode aperture region. Envelope simulation indicates that the quadrupole field can deflect electrons stripped from the negative ions. Beam envelope simulations for deuterium ions and electrons have been carried out using the beam envelope code trace. Electrons are largely divergent and most appear likely to hit downstream electrodes. Furthermore, maximum beam divergence of the deuterium ions is reduced to the focusing effect of the quadrupole magnetic field.