US3193724A - Ionization manometer - Google Patents

Ionization manometer Download PDF

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Publication number
US3193724A
US3193724A US183079A US18307962A US3193724A US 3193724 A US3193724 A US 3193724A US 183079 A US183079 A US 183079A US 18307962 A US18307962 A US 18307962A US 3193724 A US3193724 A US 3193724A
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United States
Prior art keywords
anode
plates
apertures
electron beam
collector
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Expired - Lifetime
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US183079A
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English (en)
Inventor
Klopfer Anton Martin
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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Publication date
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J41/00—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas; Discharge tubes for evacuation by diffusion of ions
    • H01J41/02—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas
    • H01J41/04—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas with ionisation by means of thermionic cathodes

Definitions

  • the invention relates to an ionization manometer in which the gas to be measured is ionised between the two apertured diaphragms, the ionising electron beam being concentrated by a magnetic field so that no electrons impinge upon the edges of the diaphragm apertures for the passage of the electron beam, while precautions are taken to prevent ions liberated from the anode from striking the collector electrode which is arranged laterally of the electron beam between the diaphragms.
  • Ionization inanorneters of the above described kind are known.
  • Their collector electrode is either cylindrical and surrounds the electron beam or is a flat plate arranged opposite other flat electrodes, a potential difference being set up between these electrodes.
  • the anode is hollow so that the liberated ions enter a field-free space and hence'are hardly capable of leaving the hollow anode. Furthermore, the anode is at a slightly negative voltage with a respect to the diaphrams through which the electrodes enter the anode.
  • the anode is a grid cage within which a thin wire is arranged as an ion collector.
  • a thermionic cathode is disposed outside the anode cage.
  • the lower measuring limit is determined by the X-ray effect, which is defined hereinafter.
  • the electrons striking the anode by their impact produce very soft X-rays which strike the ion collector also.
  • the incident X-rays liberate electrons from the ion collector electrode and thus simulate an ion current which falsifies the measurements. Since the electron current produced at the collector depends upon the surface properties, which vary with the gas covering, no constant correction can be applied.
  • the ionizing electron beam is concentrated by a magnetic field so that no electrons impinge upon the edges of the diaphragm apertures for the passage of the electron beam, while precautions are taken to prevent ions liberated from the anode from striking the collector electrode arranged laterally of the electron beam between the diaphragm.
  • the anode there is set up between the anode and the last diaphragm through which the electron beam passes a voltage of such value that the ions liberated from the anode are given a velocity sufficient to drive them under the influence of the magnetic field towards the cathode, while the ion collector electrode is so disposed with respect to the aperture in the final diaphragm that no straight lines can be drawn between the area of the anode struck by electrons and the collector electrode.
  • the first cause consists of the ions liberated from the anode, which now are given a velocity such as to prevent them from being drawn towards the collector, even if this collector is negative with respect to the diaphragm.
  • the second cause the so-called X-ray limit, is eliminated by the fact that the anode struck by electrons is prevented from seeing the ion collector so that the X-rays produced are now prevented from liberating electrons from the collector.
  • the chamber in which ionization is effected preferably is completely enclosed by electrodes joined to one another with the exception of the collector electrode, so that interference fields are reduced to a minimum.
  • FIG. 1 shows the electrode of an ionization manometer partly broken away
  • FIG. 2 shows a simple circuit arrangement comprising such an electrode system.
  • a thermionic cathode 1 which is in the form of a flat ribbon, is separated by two apertured diaphragms 2 and 3 from a metal case having a front wall 4, a rear wall 5, lateral walls 6 and 7 and an upper wall 8.
  • the electron beam emitted by the cathode 1 leaves the caseshaped chamber through an aperture 9 in the rear wall 5 (the wall 4 is also apertured) and impinges upon the anode 16.
  • a flat collector electrode 11 is supported by a rod 12, screening being effected by a flat plate 13 and a cylinder 1
  • the entire assembly is housed in an evacuated chamber 30.
  • FIG. 2 is a sectional view of the electrode system taken parallel to the direction of the electron beam and the magnetic field (indicated by an arrow 15).
  • the electron beam inpinges upon a part 16 of the anode 10 and, as is shown by a broken line 17, no straight lines can be drawn from this part 16 through the aperture 9 to the collector electrode 11.
  • the collector electrode is connected to earth by way of a direct-current amplifier 18, which may be provided with the measuring and registering instruments required.
  • the thermionic cathode 1 is given a positive voltage of about 30 volts to ground by a battery 19.
  • a filament current battery is designated 20.
  • a potentiometer 21 With the aid of a potentiometer 21 a positive voltage of about 30 volts with respect to ground is applied to the diaphragm.
  • a positive voltage of at most 200 volts is set up by a battery 22 and a potentiometer 23 at the diaphragm 3.
  • the case comprising the electrodes 4 to 8 has a positive voltage of 150 volts applied to it by a battery 24 and a potentiometer 25, a positive voltage of 250 volts being set up with the anode it) by a potentiometer 26.
  • ions liberated from the cathode surface 16 when passing through the aperture 9 have a velocity corresponding to an energy of about e.v. so that the ions travel towards the cathode under the influence of the magnetic field which is from about 600 Gauss to about 1000 Gauss.
  • the upper limit of the pressure which can be measured is about 10* Torr when the dimensions of the ionizing chamber correspond to a cube the edges which are of about 25 mm. long.
  • the lower measuring limit lies at 10 Torr.
  • An ionization manometer comprising a pair of parallel plates with aligned apertures, means to generate and project an electron beam through the apertures in said plates whereby gas between the plates is ionized, an anode electrode on the side of said plates remote from the electron beam generating means and aligned with said apertures, a magnetic field for concentrating the electron beam so that electrons in said beam pass through said apertures and strike a given area of said anode without striking the edges of said plates bounding said apertures, a collector electrode disposed between said plates and positioned so that a straight line drawn between the collector and said given area of said anode intersects one of said plates adjacent said anode, and means to apply a potential between the anode and the plate adjacent thereto at which ions liberated by the anode have a velocity sufiicient to drive them towards the cathode under the influence of the said magnetic field.

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  • Measuring Fluid Pressure (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
US183079A 1961-04-17 1962-03-28 Ionization manometer Expired - Lifetime US3193724A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEN19897A DE1156581B (de) 1961-04-17 1961-04-17 Ionisationsmanometer

Publications (1)

Publication Number Publication Date
US3193724A true US3193724A (en) 1965-07-06

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ID=7341064

Family Applications (1)

Application Number Title Priority Date Filing Date
US183079A Expired - Lifetime US3193724A (en) 1961-04-17 1962-03-28 Ionization manometer

Country Status (4)

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US (1) US3193724A (de)
CH (1) CH412395A (de)
DE (1) DE1156581B (de)
GB (1) GB964120A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3280365A (en) * 1963-04-15 1966-10-18 Gen Electric Penning-type discharge ionization gauge with discharge initiation electron source
US3320455A (en) * 1966-04-22 1967-05-16 Gen Electric Ionization vacuum gauge having x-ray shielding means
US3387175A (en) * 1965-03-05 1968-06-04 Varian Associates Vacuum gauge having separate electron collecting and electron accelerating electrodes
US3394286A (en) * 1965-05-27 1968-07-23 Nat Res Corp Ultrahigh vacuum measuring ionization gauge
US3463956A (en) * 1966-05-17 1969-08-26 Janusz Groszkowski Ionization vacuum gauge with x-ray and ultraviolet ray shielding
US3496399A (en) * 1966-12-12 1970-02-17 Edwards High Vacuum Int Ltd Ion gauge with collector plates anf anodes perpendicular to each other

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5128617A (en) * 1990-04-11 1992-07-07 Granville-Phillips Company Ionization vacuum gauge with emission of electrons in parallel paths

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2937295A (en) * 1957-05-07 1960-05-17 Ca Nat Research Council Ionization gauge for the measurement of low pressures
US3051868A (en) * 1960-08-29 1962-08-28 Ca Nat Research Council Ionization vacuum gauges

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE753159C (de) * 1941-10-19 1954-07-19 Siemens & Halske A G Ionisationsmanometer
DE843313C (de) * 1951-02-27 1952-08-14 Telefunken Gmbh Elektrische Entladungseinrichtung mit einer Gluehkathode, einer Ionisierungselektrode und einer Ionenauffangelektrode zum Messen des im Entladungsraum herrschenden Gasdruckes mittels des zur Ionenauffangelektrode uebergehenden Ionenstromes

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2937295A (en) * 1957-05-07 1960-05-17 Ca Nat Research Council Ionization gauge for the measurement of low pressures
US3051868A (en) * 1960-08-29 1962-08-28 Ca Nat Research Council Ionization vacuum gauges

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3280365A (en) * 1963-04-15 1966-10-18 Gen Electric Penning-type discharge ionization gauge with discharge initiation electron source
US3387175A (en) * 1965-03-05 1968-06-04 Varian Associates Vacuum gauge having separate electron collecting and electron accelerating electrodes
US3394286A (en) * 1965-05-27 1968-07-23 Nat Res Corp Ultrahigh vacuum measuring ionization gauge
US3320455A (en) * 1966-04-22 1967-05-16 Gen Electric Ionization vacuum gauge having x-ray shielding means
US3463956A (en) * 1966-05-17 1969-08-26 Janusz Groszkowski Ionization vacuum gauge with x-ray and ultraviolet ray shielding
US3496399A (en) * 1966-12-12 1970-02-17 Edwards High Vacuum Int Ltd Ion gauge with collector plates anf anodes perpendicular to each other

Also Published As

Publication number Publication date
DE1156581B (de) 1963-10-31
CH412395A (de) 1966-04-30
GB964120A (en) 1964-07-15

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