Ionization vacuum gauge with emission of electrons in parallel paths
AssigneeGranville-Phillips Company
InventorDaniel G. Bills
Life of this patent
Estimating the term…
Abstract
An ionization gauge and controller therefor where the gauge has a sensitivity which is reproducible gauge to gauge and stable over time in the same gauge. An ionization gauge with a very much lower and a somewhat higher pressure limit than prior art gauges is also disclosed. Elements are also described for launching all electrons in a tight beam in Bayard-Alpert type geometry, so that all the conditions for reproducible and stable sensitivity are satisfied. Elements are also described for collecting all electrons at low energy so that soft X-ray production is negligible.
Claims101
An ion gauge comprising
- a cylindrical anode having an axis of cylindrical symmetry where an anode volume is defined within the anode and the anode is at least partially open to permit the passage of electrons from outside the anode into the anode volume;
- an outer electrode surrounding the anode;
- an ion collector substantially disposed along said axis of symmetry of the anode;
- at least one cathode for emitting electrons disposed outside the anode and axially extending substantially parallel to the axis of the anode;
- means for launching the emitted electrons in substantially parallel paths directed substantially toward an imaginary axis radially displaced from and substantially parallel to the anode axis;
- and
- means for collecting the electrons emitted from the cathode after they have passed through the anode volume.
An ion gauge comprising
- a cylindrical anode having an axis of cylindrical symmetry where an anode volume is defined within the anode and the anode is at least partially open to permit the passage of electrons from outside the anode into the anode volume;
- an outer electrode surrounding the anode;
- an ion collector substantially disposed along said axis of symmetry of the anode;
- at least one cathode for emitting electrons disposed outside the anode and axially extending substantially parallel to the axis of the anode, said cathode having a substantially flat electron emitting surface which faces an imaginary axis radially displaced from and substantially parallel to the anode axis such that electrons emitted from the flat cathode surface are launched in substantially parallel paths directed substantially toward the imaginary axis;
- and
- means for collecting the electrons emitted from the cathode after they have passed through the anode volume.
An ion gauge comprising
- a cylindrical anode having an axis of cylindrical symmetry where an anode volume is defined within the anode and the anode is at least partially open to permit the passage of electrons from outside the anode into the anode volume;
- an outer electrode surrounding the anode;
- an ion collector substantially disposed along an imaginary axis radially displaced from and substantially parallel to said axis of symmetry of the anode;
- at least one cathode for emitting electrons disposed outside the anode and axially extending substantially parallel to the axis of the anode;
- means for launching the emitted electrons in substantially parallel paths directed substantially toward the axis of symmetry of the anode;
- and
- means for collecting the electrons emitted from the cathode after they have passed through the anode volume.
An ion gauge comprising
- a cylindrical anode having an axis of cylindrical symmetry where an anode volume is defined within the anode and the anode is at least partially open to permit the passage of electrons from outside the anode into the anode volume;
- an outer electrode surrounding the anode;
- an ion collector substantially disposed along an imaginary axis radially displaced from and substantially parallel to said axis of symmetry of the anode;
- at least one cathode for emitting electrons disposed outside the anode and axially extending substantially parallel to the axis of the anode, said cathode having a substantially flat electron emitting surface which faces the axis of symmetry of the anode such that electrons emitted from the flat cathode surface are launched in substantially parallel paths directed substantially toward the axis of symmetry of the anode;
- and
- means for collecting the electrons emitted from the cathode after they have passed through the anode volume.
Controller circuitry for controlling the operation of an ion gauge including a substantially cylindrical anode, an outer electrode surrounding the anode, an ion collector, and a cathode for emitting electrons into an anode volume defined within the anode, said circuitry comprising:
- means for biasing the cathode at the approximate local potential prevailing in the region of the cathode;
- and
- means for biasing the anode at a potential sufficient to accelerate the emitted electrons to an effective energy for causing ionization of a gas in the anode volume.
Controller circuitry for controlling the operation of an ion gauge including an anode where an anode volume is defined by the anode and the anode is at least partially open to permit the passage of electrons from outside the anode into the anode volume and where the anode includes an exit aperture through which the electrons exit from the anode volume;
- an outer electrode surrounding the anode;
- at least one ion collector;
- at least one cathode disposed outside the anode for emitting electrons through the anode into the anode volume;
- and an electron collecting electrode spaced separate from the anode for collecting the electrons exiting from the anode volume through the exit aperture, said circuitry comprising
- means for providing a bias voltage between the cathode and anode sufficient to accelerate the emitted electrons to an effective energy for causing ionization of a gas in the anode volume;
- and
- means for biasing said electron collecting electrode so that the electrons are collected at substantially lower energy than if they were collected at the anode.
A pressure measuring method utilizing an ion gauge having a cylindrical anode having an axis of cylindrical symmetry where an anode volume is defined within the anode and the anode is at least partially open to permit the passage of electrons from outside the anode into the anode volume;
- an outer electrode surrounding the anode;
- an ion collector substantially disposed along said axis of symmetry of the anode;
- and at least one cathode for emitting electrons disposed outside the anode and axially extending substantially parallel to the axis of the anode;
- and means responsive to current in the ion collector for measuring said pressure;
- said method comprising the steps of:
- launching the emitted electrons in substantially parallel paths directed substantially toward an imaginary axis radially displaced from and substantially parallel to the anode axis;
- and
- collecting the electrons emitted from the cathode after they have passed through the anode volume.
A pressure measuring method utilizing an ion gauge having a cylindrical anode having an axis of cylindrical symmetry where an anode volume is defined within the anode and the anode is at least partially open to permit the passage of electrons from outside the anode into the anode volume;
- an outer electrode surrounding the anode;
- an ion collector substantially disposed along an imaginary axis radially displaced from and substantially parallel to said axis of symmetry of the anode;
- at least one cathode for emitting electrons disposed outside the anode and axially extending substantially parallel to the axis of the anode;
- and means responsive to current in the ion collector for measuring said pressure;
- said method comprising the steps of:
- launching the emitted electrons in substantially parallel paths directed substantially toward an axis of symmetry of the anode;
- and
- collecting the electrons emitted from the cathode after they have passed through the anode volume.
A pressure measuring method for use with controller circuitry for measuring said pressure by controlling the operation of an ion gauge including a substantially cylindrical anode, an outer electrode surrounding the anode, an ion collector, and a cathode for emitting electrons into an anode volume defined within the anode, said method comprising the steps of:
- biasing the cathode at the approximate local potential prevailing in the region of the cathode;
- and
- biasing the anode at a potential sufficient to accelerate the emitted electrons to an effective energy for causing ionization of a gas in the anode volume.
A pressure measuring method utilizing an ion gauge having an anode where an anode volume is defined by the anode and the anode is at least partially open to permit the passage of electrons from outside the anode into the anode volume and where the anode includes an exit aperture through which the electrons exit from the anode volume;
- an outer electrode surrounding the anode;
- at least one ion collector;
- at least one cathode disposed outside the anode for emitting electrons through the anode into the anode volume;
- and an electron collecting electrode separate from the anode for collecting the electrons exiting from the anode volume through the exit aperture, and means responsive to current in the ion collector for measuring said pressure;
- said method comprising:
- biasing said electron collecting means so that the electrons are collected at substantially lower energy than if they were collected at the anode.
Dependencies are inferred from the claim text.