Ionization gauge with a cold electron source
AssigneeBrooks Automation, Inc.
InventorsRichard A. Knott, Gerardo A. Brucker, Paul C. Arnold
Life of this patent
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Abstract
An ionization gauge that eliminates a hot cathode or filament, but maintains a level of precision of gas density measurements approaching that of a hot cathode ionization gauge. The ionization gauge includes a collector electrode disposed in an ionization volume, an electron source without a heated cathode, and an electrostatic shutter that regulates the flow of electrons between the electron source and the ionization volume. The electrostatic shutter controls the flow of electrons based on feedback from an anode defining the ionization volume. The electron source can be a Penning or glow discharge ionization gauge.
Claims28
An ionization gauge comprising:
- a cold cathode electron source comprising an electron source volume in which electrons are generated;
- an ionization volume distinct from the electron source volume;
- a collector electrode disposed in the ionization volume, the collector electrode configured to collect ions formed by the impact between the electrons and gas molecules and atoms to provide a gas pressure output;
- and
- an electrostatic shutter between the electron source volume and the ionization volume configured to control the flow of electrons from the electron source volume to the ionization volume.
An ionization gauge comprising:
- a cold cathode electron source comprising an electron source volume in which electrons are generated;
- an ionization volume distinct from the electron source volume;
- a first collector electrode, and a second collector electrode with both being disposed in the ionization volume, the first and second collector electrodes configured to collect ions formed by the impact between the electrons and gas molecules and atoms to provide a gas pressure output;
- and
- an electrostatic shutter between the electron source volume and the ionization volume configured to control the flow of electrons from the electron source volume to the ionization volume.
A method of measuring a gas pressure from gas molecules and atoms, comprising:
- generating electrons in a cold cathode electron source comprising an electron source volume;
- regulating the flow of electrons by an electrostatic shutter between the electron source volume and an ionization volume distinct from the electron source volume;
- and
- collecting ions formed by an impact between the electrons and the gas molecules and atoms in the ionization volume to provide a gas pressure output.
An ionization gauge comprising:
- a cold cathode electron source comprising an electron source volume in which electrons are generated;
- an ionization volume distinct from the electron source volume;
- a collector electrode disposed in the ionization volume, the collector electrode configured to collect ions formed by the impact between the electrons and gas molecules and atoms to provide a gas pressure output;
- an electrostatic shutter between the electron source volume and the ionization volume configured to control the flow of electrons from the electron source volume to the ionization volume;
- and
- an envelope surrounding the electron source volume and the electrostatic shutter, the envelope permitting electrons from a predetermined electric potential to enter into the ionization volume.
A method of measuring a gas pressure from gas molecules and atoms comprising:
- generating electrons in a cold cathode electron source comprising an electron source volume;
- regulating the flow of electrons by an electrostatic shutter between the electron source volume and an ionization volume distinct from the electron source volume;
- controlling the electron energy from the electron source;
- and
- collecting ions formed by an impact between the electrons and gas molecules and atoms in the ionization volume to provide a gas pressure output.
Dependencies are inferred from the claim text.