Deflection of an ion beam in the two-dimensional electrostatic quadrupole field

Abstract

The deflecting properties of a two‐dimensional quadrupole field have been calculated to second order in input position, angle, and energy. The use of this field as an energy analyzer and as an achromatic deflector are described. The calculated dispersion, which is 84.5% that of of a 127° analyzer of equal angular aberration, has been confirmed by measurement on a deflector designed and built for merging an ion beam with a laser beam. This deflector can bend a 3‐kV ion beam of 2‐mm diameter, ±2‐mrad angular spread, and 1‐eV FWHM energy spread by 90° without causing a detectable increase in the diameter or angular spread of the beam.