Agilent Technologies, Inc.
ION GUIDE WITH VARYING MULTIPOLES

Abstract:

An ion guide includes electrodes elongated along an axis from an entrance end to an exit end and spaced around the axis to surround an interior. The electrodes have polygonal shapes with inside surfaces disposed at a radius from the axis and having an electrode width tangential to a circle inscribed by the electrodes. An aspect ratio of the electrode width to the radius varies along the axis. The electrodes are configured to generate a two-dimensional RF electrical field in the interior having a multipole composition comprising one or more lower-order multipole components and one or more higher-order multipole components and varying along the axis in accordance with the varying aspect ratio, and having an RF voltage amplitude that varies along the axis.