Ion cyclotron resonance spectrometer

Abstract

A method of operating an ICR spectrometer comprising a measuring cell (1) having a plurality of side walls (3, 4) designed as rf electrodes and arranged symmetrically to an axis (2) extending in parallel to the field direction of a magnetic field, and further electrically insulated trapping electrodes (5, 6) arranged on both sides of the cell, viewed in the direction of the axis, which trapping electrodes can be supplied with trapping potentials of the polarity of the ions under examination in order to prevent, to a large extent, the ions from leaving the measuring cell (1) in the direction of the axis, provides that, in order to minimize the components of the electric rf field directed in parallel to the axis, which act upon the ions in the measuring cell (1), additional electric rf signals are applied to at least one said trapping electrode (5) on both sides of the said measuring cell (1). One thereby obtains in the measuring cell (1) a behavior of the electric rf field lines corresponding approximately to that which would be obtained, theoretically, in a measuring cell (1) of infinite axial length. This prevents axial acclerations of the ions in the measuring cell (1) by the electric rf field, which normally result in these ions being lost for the measuring process.

Dependencies are inferred from the claim text.