Mass spectrometer

摘要

A mass spectrometer is disclosed comprising a quadrupole rod set ion trap wherein a potential field is created at the exit of the ion trap which decreases with increasing radius in one radial direction. Ions within the ion trap are mass selectively excited in a radial direction. Ions which have been excited in the radial direction experience a potential field which no longer confines the ions axially within the ion trap but which instead acts to extract the ions and hence causes the ions to be ejected axially from the ion trap.

主权项

1. An ion trap comprising:
a first electrode set comprising a first plurality of electrodes having a first longitudinal axis; a second electrode set comprising a second plurality of electrodes having a second longitudinal axis, said second electrode set being arranged downstream of said first electrode set; a first device arranged and adapted to apply one or more DC voltages to one or more of said first plurality of electrodes or to one or more of said second plurality of electrodes so as to create, in use, an electric potential within said first electrode set or within said second electrode set which increases or decreases or varies with radial displacement in a first radial direction as measured from a central longitudinal axis of said first electrode set or said second electrode set; a second device arranged and adapted to excite at least some ions within said first electrode set in at least one radial direction or to increase the radial displacement of at least some ions in at least one radial direction within said first electrode set; a first plurality of vane or secondary electrodes arranged between the electrodes of the first electrode set or a second plurality of vane or secondary electrodes arranged between the electrodes of the second electrode set; and a device arranged and adapted to apply one or more first DC voltages or one or more second DC voltages to at least some of said vane or secondary electrodes.