Minimisation of the aberrations of electrostatic lens systems composed of quadrupole and octupole lenses

• Published in: International journal of mass spectrometry Vol. 189; no. 1; pp. 19 - 26
• Main Authors: Baranova, L.A., Read, F.H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1999
• Subjects: Aberration; Electron; Electrostatic; Lens; Multiplets; Quadrupole; Quadrupole; Lens; Aberration; Multiplets; Electrostatic; Electron
• ISSN: 1387-3806; 1873-2798
• DOI: 10.1016/S1387-3806(99)00042-1

Aberrations are investigated and compared for two types of multiplets based on electrostatic quadrupole and octupole lenses: “mid-acceleration” systems where an accelerating potential is applied to the middle lenses of a set of quadrupole lenses and systems where some of the quadrupole lenses are replaced by combined quadrupole–octupole lenses. It is shown that for systems consisting of three lenses the mid-acceleration type has the smaller aberrations. For systems consisting of four or five lenses the third order aperture aberration can be eliminated in the quadrupole–octupole type. The mid-acceleration type has the advantages of lower levels of chromatic and fifth order aperture aberrations and also relative simplicity of construction and voltage adjustment.