Field conditions for ion excitation in linear ion processing apparatus
AssigneeVarian, Inc.
InventorGregory Wells
Life of this patent
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Abstract
Methods for applying an RF field in a two-dimensional electrode structure include applying RF voltages to main electrodes and to compensation electrodes. The voltages on the compensation electrodes may be proportional to the voltages on the main electrodes so as to optimize the RF field for processes involving ion excitation, including collision-induced dissociation. Electrode structures may include main trapping electrodes, one or more compensation electrodes, one or more ion exit apertures, and a device or circuitry for applying the various desired voltages.
Claims20
A method for applying an RF field in an electrode structure, the electrode structure including a plurality of main electrodes coaxially disposed about a central axis and extending generally in the direction of the central axis, the main electrodes defining an interior space extending along the central axis, the method comprising:
- applying a first RF voltage to at least two of the main electrodes at a first amplitude;
- and
- applying a second RF voltage to a compensation electrode at a second amplitude different from the first amplitude, the compensation electrode disposed in the interior space proximate to a corresponding main electrode at a radial distance from the central axis less than the radial distance of the corresponding main electrode from the central axis.
A method for applying an RF field in an electrode structure, the electrode structure including a plurality of main electrodes coaxially disposed about a central axis and extending generally in the direction of the central axis, the main electrodes defining an interior space extending along the central axis, at least one of the main electrodes having an aperture, the method comprising:
- applying a first RF voltage to at least two of the main electrodes at a first amplitude;
- and
- applying a second RF voltage to a compensation electrode at a second amplitude different from the first amplitude, the compensation electrode disposed in the interior space entirely outside of the aperture.
A method for applying an RF field in an electrode structure, the electrode structure including a plurality of main electrodes coaxially disposed about a central axis and extending generally in the direction of the central axis, the main electrodes defining an interior space extending along the central axis, at least one of the main electrodes including a curved section and an aperture generally disposed at an apical portion of the curved section, the method comprising:
- applying a first RF voltage to at least two of the main electrodes at a first amplitude;
- and
- applying a second RF voltage to a compensation electrode at a second amplitude different from the first amplitude, the compensation electrode disposed at a tangent line tangent to the apical portion of the curved section of the at least one main electrode.
Dependencies are inferred from the claim text.