Patent ID: 7960694
Filing Date: 2011-06-14
Classification: H01J

Abstract:
1. A mass analyser comprising: an ion guide comprising a plurality of electrodes; means for applying a first AC or RF voltage having a first frequency and a first amplitude to at least some of said plurality of electrodes such that, in use, one or more axial time averaged or pseudo-potential barriers, corrugations or wells are created along at least a portion of the axial length of said ion guide; means for applying a second AC or RF voltage having a second frequency and a second amplitude to one or more electrodes in order to confine ions radially in use within said ion guide; and means for driving or urging ions along and/or through at least a portion of the axial length of said ion guide so that in a mode of operation ions having mass to charge ratios within a first range exit said ion guide whilst ions having mass to charge ratios within a second different range are axially trapped or confined within said ion guide by said plurality of axial time averaged or pseudo-potential barriers, corrugations or wells.