Abstract: A method and apparatus for Fourier transform mass spectrometry is disclosed in which charged particles in a magnetic field are subjected to a high voltage pulse and caused to be accelerated to larger radii of gyration. After the pulse is turned off, the charged particles move in circular orbits at frequencies given by the cyclotron equation, w=qB/m, where B is the magnetic field strength and q/m is their respective charge-to-mass ratios. The excited cyclotron motions induce the transient signal on the plates of an analyzer cell. This signal, which is a composite of all the various cyclotron frqeuencies, is digitized and stored in a computer. A mass spectrum of the ions in the analyzer cell is obtained by subjecting the signal to a Fourier transform analysis to separate the individual cyclotron frequency components. One of the advantages of this method is that the high voltage pulse accelerates all ions in the cell simultaneously.

Abstract: A mass spectrometer having an ion cyclotron resonance analyzer cell disposed in a homogenous magnetic field with an ionizer outside the magnetic field for forming ions to be analyzed in the cell and an interface for introducing ions from said ionizer into said ion cyclotron resonance cell for analysis.

Abstract: A trapped ion cyclotron resonance mass spectrometer comprised of an analyzer cell having upper, lower, side and end electrodes positioned to produce a substantially uniform electric field, a magnet positioned to produce a magnetic field and irradiating wires adjacent to the electrodes for producing an RF alternating field. The upper, lower and side electrodes are in the form of a rectangular hyberbola to produce a homogeneous quadrupolar electrostatic field. Sample ions are produced by reaction with a reagent ion and trapped by the electric and magnetic fields. The magnetic field induces the trapped ions into an orbit at a frequency related to the charge-to-mass ratio. The analyzer cell is then irradiated with an alternating electric field which causes the ions to accelerate until they impinge on the upper and lower electrodes and are collected. An electrometer connected to the upper and lower electrodes senses the collected ions and measures the current produced.