Ejection of ions from ion traps by combined electrical dipole - and quadrupole fields

摘要

the invention relates to an improved process and apparatus for the massensequentiellen ejection of ions from an rf quadrupol - ionenfalle electrical alternating fields.in addition to the quadrupolaren high-frequency speicherfeld and of different frequencies are generated.in contrast to the already known ejection by a pure dipolfeld here the ions mainly by a quadrupolfeld ejected.the ions leave the ionenfalle through a perforated endkappe, and outside the ionenfalle with usual methods are demonstrated.a weak dipolfeld assumes only the excitation of the sekularschwingung in the center, the amplitude grows in the stationary state in a linear fashion.the stronger quadrupolfeld takes the extension of vibration with a geometric growth of the amplitudes.the dipolfeld by an alternating voltage between the two end caps produced by the quadrupolfeld an alternating voltage between the end caps on the one hand and, on the other hand, the ringelektrode.the method is especially for very high mass ions in the range of about 5000 to 50000).it allows for the same massenauflu00f6sung a much faster uptake of certain than previously used application of pure dipolfelder.