Patent ID: 7351961
Filing Date: 2008-04-01
Classification: H01J

Abstract:
1. A measurement cell for an FTMS spectrometer, comprising: an excitation electrode arrangement positioned about a longitudinal axis which extends in a direction generally parallel to the field direction of an applied homogeneous magnetic field, the excitation electrode arrangement including a central excitation electrode part and first and second outer excitation electrode parts axially spaced from the central excitation electrode part; and a trapping electrode arrangement, also positioned about the longitudinal axis, for trapping ions longitudinally in the cell within a trapping region defined by the trapping electrode arrangement, the trapping electrode arrangement including first and second trapping electrodes located axially between the central excitation electrode part and the first and second outer excitation electrode parts respectively; wherein at least a part of the excitation electrode arrangement extends axially outwardly of the trapping region defined by the trapping electrode arrangement.