An ion guide for transferring ions to a mass analyzer is disclosed. The ion guide is characterized in that a plurality of DC rings and a plurality of RF multi-pole rings with a plurality of electrodes are arranged alternatingly along a central axis between an inlet into which the ions move and an outlet for transferring the ions. The inner diameter of the DC rings is kept constant and the inner diameter of the RF multi-pole rings gradually decreases in a direction from the inlet to the outlet.

One or more ions are received along a central axis through a first set of reflectron plates of an ELIT. Voltages are applied to the first set of plates and to a second set of reflectron plates in order to trap and oscillate the one or more ions. A first induced current is measured from a cylindrical pickup electrode between the first set of reflectron plates and the second set of reflectron plates. A second induced current is measured from one or more plates of the first set of reflectron plates. A third induced current is measured from one or more plates of the second set of reflectron plates. The first measured induced current, second measured induced current and third measured induced current are combined to reduce higher order frequency harmonics of the induced current.

A traveling wave multipole comprising two or more pairs of segmented electrodes arranged around a central axis; and a voltage supply. The voltage supply configured to supply the segments of each pair of electrodes with a different RF and DC potential; and match RF and DC potentials with a location of an ion of target m/z moving through the traveling wave multipole such that as the ion travels along the multipole the ion experiences the same RF and DC potentials while another ion of a second target m/z concurrently experiences a different RF and DC potentials at another location within the traveling wave multipole.

Apparatus comprise an electrode arrangement comprising a plurality of electrodes defining a volume, an ion entrance, and an ion exit, and a voltage source coupled to the plurality of electrodes and configured to apply a nonlinear DC voltage sequence to the electrodes between the ion entrance and the ion exit that directs ions through the volume with the volume at a pressure of at least 1 Torr. Ions can be focused using nonlinear DC voltage sequences, including at atmospheric pressure. Related methods are also disclosed.

An ion guide is disclosed comprising a first array of electrodes and a second array of electrodes and one or more apertures or ion exit regions. The first array of electrodes comprises a first plurality of arcuate electrodes arranged in parallel with one another and such that said first plurality of arcuate electrodes at least partially surround said one or more apertures or ion exit regions and/or wherein said second array of electrodes comprises a second plurality of arcuate electrodes arranged in parallel with one another and such that said second plurality of arcuate electrodes at least partially surround said one or more apertures or ion exit regions. The ion guide comprises a first device arranged and adapted to apply an AC or RF voltage to said first array of electrodes and to said second array of electrodes so as to confine ions within said ion guide in a first (z) direction that extends in a direction between said first and second arrays, and a second device arranged and adapted to apply one or more DC voltages to said first array of electrodes and/or to said second array of electrodes so as to urge ions within said ion guide in a second (r) direction towards said one or more apertures or ion exit regions, such that ions within said ion guide are caused to migrate to said one or more apertures or ion exit regions.

A Time of Flight analyser comprising a flight tube (160) and a reflectron (170), wherein the reflectron comprises a stack of electrodes (172) that are compressed against the flight tube such that they remain parallel to each other under compression.

An ion trap apparatus is provided. The ion trap apparatus comprises two or more radio frequency (RF) rails formed with substantially parallel longitudinal axes and with substantially coplanar upper surfaces; and two or more sequences of trapping and/or transport (TT) electrodes with each sequence formed to extend substantially parallel to the substantially parallel longitudinal axes of the RF rails. The two or more RF rails and the two or more sequences of TT electrodes define an ion trap. The two or more sequences of TT electrodes are arranged into a number of zones. Each zone comprises wide matched groups of TT electrodes and at least one narrow matched group of TT electrodes. A wide TT electrode is longer and/or wider in a direction substantially parallel to the substantially parallel longitudinal axes of the RF rails than a narrow TT electrode.

A first multipole assembly includes a first plurality of rod electrodes arranged about an axis and configured to confine ions radially about the axis. A second multipole assembly disposed adjacent to the first multipole assembly includes a second plurality of rod electrodes arranged about the axis and configured to confine the ions radially about the axis. An orientation of the first multipole assembly about the axis is rotationally offset relative to an orientation of the second multipole assembly about the axis.

An ion guide is disclosed that comprises a plurality of electrodes arranged to form a multipole ion guide and one or more rigid support members. The plurality of electrodes comprises one or more groups of electrodes, and each group of electrodes comprises plural electrodes that are axially spaced apart from one another. The electrodes of one or more groups of electrodes are attached to one of the one or more rigid support members. One or more of the electrodes comprises a curved metal sheet, plate or strip.

Disclosed herein is an ion guide for guiding an ion beam along an ion path, said ion guide having a longitudinal axis corresponding to said ion path, said ion guide-comprising a plurality of elongate electrodes arranged around and extending along said longitudinal axis wherein an inner envelope of the plurality of electrodes defines an ion guide volume. Said elongate electrodes are formed by electrode wires, wherein adjacent electrode wires are arranged at an inter-wire distance. The ion guide comprises holding structures for supporting and for straightening the electrode wires by applying a tension or maintaining a tension applied to them. Any portion of said holding structures which is separated from said ion guide volume by less than the local inter-wire distance is made from a material having a resistivity of less than 10.sup.12 Ohm.Math.cm, preferably of less than 10.sup.9 Ohm.Math.cm, or has a sheet resistivity of less than 10.sup.14 Ohm, preferably of less than 10.sup.10 Ohm on a surface facing said ion guide volume.