Patent ID: 8658970
Filing Date: 2014-02-25
Classification: H01J

Abstract:
1. An ion guide comprising a plurality of axial groupings of electrodes for generating an applied electric field, wherein each axial grouping of electrodes comprises a ring or annular electrode which has been radially segmented into a plurality of electrode segments wherein in a first mode of operation ions are confined radially within said ion guide by a non-quadrupolar radial pseudo-potential well and wherein in a second mode of operation ions are confined radially within said ion guide by a substantially quadrupolar radial pseudo-potential well; wherein in said first mode of operation most or all electrode segments in first, third, fifth and seventh axial groupings of electrodes are maintained at substantially a same first phase of a first AC or RF voltage and wherein for each mode voltage phases are selectively applied to individual sets of radial electrode segments of the axial groupings of electrodes.