Rotating field mass and velocity analyzer
AssigneeCalifornia Institute of Technology
InventorsSteven Joel Smith, Ara Chutjian
Life of this patent
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Abstract
A rotating field mass and velocity analyzer having a cell with four walls, time dependent RF potentials that are applied to each wall, and a detector. The time dependent RF potentials create an RF field in the cell which effectively rotates within the cell. An ion beam is accelerated into the cell and the rotating RF field disperses the incident ion beam according to the mass-to-charge (m/e) ratio and velocity distribution present in the ion beam. The ions of the beam either collide with the ion detector or deflect away from the ion detector, depending on the m/e, RF amplitude, and RF frequency. The detector counts the incident ions to determine the m/e and velocity distribution in the ion beam.
Claims24
A mass analyzer for identifying mass and velocity distributions in an ion beam comprising:
- a cell receiving said ion beam;
- means for creating a rotating RF field imparting a non-magnetic field within said cell, wherein said cell is a magnetic field free cell;
- and
- a detector located in close proximity to said cell for counting ions in said ion beam.
A mass analyzer for identifying mass and velocity distributions in an ion beam comprising:
- a cell comprising at least two walls with time-dependent alternating RF potentials applied to each wall;
- a rotating RF field imparting a non-magnetic field and located within the cell, wherein said cell is a magnetic field free cell;
- a detector located at an end of said cell for counting ions in said ion beam.
A mass analyzer for identifying mass and velocity distributions in an ion beam comprising:
- first and second consecutive cells, each having two walls orthogonally oriented;
- time-dependent alternating RF potentials applied to each wall, wherein said RF potentials create crossed electric fields within each cell to generate a non-magnetic rotating RF field within each cell, wherein said cell is a magnetic field free cell;
- a detector located at an end of said cells for counting ions in said ion beam.
A method for identifying mass and velocity distributions in an ion beam projected into a cell with at least two walls, comprising the steps of:
- applying time-dependent alternating RF potentials to each wall of the cell to create crossed electric fields in the cell;
- generating non-magnetic rotating RF fields within the cell, wherein said cell is a magnetic field free cell;
- accelerating the ion beam into the cell;
- dispersing the ion beam according to the mass and velocity distribution present in the ion beam by the rotating RF field;
- and
- counting ions in said ion beam.
Dependencies are inferred from the claim text.