QUADRUPOLE ION TRAP WITH ELECTRONIC SHIMS

摘要

There is provided a quadrupole ion trap mass spectrometer of the type having a plurality of ring electrodes and defining a trapping volume (19). The quadrupole potential faults arising from apertures in the electrodes are corrected by an apertured shim electrode (41, 42) placed within and spaced from the walls of the electrode apertures (16, 18).