Method and apparatus for mass analysis with the use of a quadrupole - mass filters

摘要

Methods for spatially separating ac and dc electric fields in which materials are used having characteristics as dielectrics to the ac fields and as conductors to the dc fields. The apparatus for separating the fields utilizes homogeneous materials of moderate to high resistivity. The method is applied to the separation of fringe fields near the ends of quadrupole mass filters for the purpose of improving the efficiency of ejection and transmission of ions in mass filter devices.