New Viewpoints in Mass Filter Design
Abstract
Explicit differential equations in closed form have been found for pole piece geometries which are generalizations of those used in the QMF. For arbitrarily shaped pole pieces, the solution of Laplace's equation cannot be written in closed form and, thus in general the ion differential equations of motion cannot be written in closed form. The geometries shown in figures 4, 5 and 6 are analytically useful in determining if other geometries might yield mass filters with improved resolution/transmission characteristics. Computer simulation of ion motion in these geometries is a subject for future research. The principal new results of our research are: 1) new derivations of the equations which describe ion motion in a QMF, 2) the equations of pole pieces for hexapole, octupole and decapole geometries illustrated in figures 4, 5 and 6, 3) closed form differential equations of ion motion in these geometries (equations (17), (20) and (21) and 4) the realization that the inverted pendulum is a mechanical analog of the QMF.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 18, 1982
- Accession Number
- ADA117295
Entities
People
- Alfred L. Yergey
- Joseph E. Campana
- Melvin H. Friedman