Patent ID: 9412578
Filing Date: 2016-08-09
CPC Classification: H01J

Claim Text:
1. A method of analyzing ions in a mass analyser, the mass analyzer having a longitudinal axis z, the mass analyser including two opposing mirrors, the mirrors comprising inner and outer field-defining electrode systems elongated along the axis z, the outer system surrounding the inner and defining therebetween an analyzer volume, whereby when the electrode systems are given a first set of one or more electrical potentials the mirrors create a main analyzer electrical field, comprising the steps: injecting a beam of ions along an injection trajectory into the mass analyser whereby the ions commence upon a main flight path within the mass analyzer in the main analyzer electric field, wherein the ions on the main flight path follow the main flight path under the influence of the main analyzer electrical field and undergo at least one oscillation back and forth in the direction of the longitudinal axis z and more than one orbit around the longitudinal axis z, the main flight path has a generally cylindrical envelope about the z-axis; and wherein electrical potentials of both the inner and outer field defining electode systems are not changed during injection such that the main analyzer field is not changed during injection.