US3173048A - Ion vacuum pump for magnetrons controlled for leakage of magnetron magnet - Google Patents

Ion vacuum pump for magnetrons controlled for leakage of magnetron magnet Download PDF

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Publication number
US3173048A
US3173048A US93399A US9339961A US3173048A US 3173048 A US3173048 A US 3173048A US 93399 A US93399 A US 93399A US 9339961 A US9339961 A US 9339961A US 3173048 A US3173048 A US 3173048A
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US
United States
Prior art keywords
leakage
envelope
vacuum pump
magnetrons
controlled
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US93399A
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English (en)
Inventor
Herbert H Chun
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Varian Medical Systems Inc
Original Assignee
Varian Associates Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to DENDAT1248819D priority Critical patent/DE1248819B/de
Application filed by Varian Associates Inc filed Critical Varian Associates Inc
Priority to US93399A priority patent/US3173048A/en
Priority to GB8450/62A priority patent/GB928012A/en
Priority to FR890221A priority patent/FR1316966A/fr
Application granted granted Critical
Publication of US3173048A publication Critical patent/US3173048A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/34—Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/02—Electrodes; Magnetic control means; Screens
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/02—Electrodes; Magnetic control means; Screens
    • H01J23/10—Magnet systems for directing or deflecting the discharge along a desired path, e.g. a spiral path
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/50—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field
    • H01J25/52—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field with an electron space having a shape that does not prevent any electron from moving completely around the cathode or guide electrode
    • H01J25/58—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field with an electron space having a shape that does not prevent any electron from moving completely around the cathode or guide electrode having a number of resonators; having a composite resonator, e.g. a helix
    • H01J25/587—Multi-cavity magnetrons
    • 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
    • H01J41/12—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps
    • H01J41/18—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps with ionisation by means of cold cathodes
    • H01J41/20—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps with ionisation by means of cold cathodes using gettering substances

Definitions

  • the present invention relates generally to high vacuum electron discharge devices and, in particular, to novel means for extending the operational life of such devices.
  • Electron discharge devices envisaged in the application of the present invention include oscillator, amplifier and modulator tubes wherein an external magnetic field is an essential component and electron emission within a high vacuum envelope is the primary mechanism.
  • the principal feature of the present invention is the removal of gaseous contaminants from the high vacuum envelope by means of externally appended getter ion vacuum pump apparatus employing the magnetic field provided as a component of the completely packaged electron discharge tube.
  • the pump apparatus may be extremely small and is simply activated by an external DC. voltage supply.
  • FIG. 1 is a side elevation of an illustrative embodiment of the invention, namely a magnetron oscillator tube viewed from the output side;
  • FIG. 2 is a view of the embodiment shown in FIG. 1 rotated through 90 with a portion of the external magnet structure cut away;
  • FIG. 3 is a perspective view of the illustrative embodiment of FIG. 2 rotated 180.
  • FIG. 4 is a cross section taken along the lines 44 of FIG. 1.
  • an embodiment of the invention of the magnetron oscillator class having a highly evacuated envelope or tube body 1 enclosing the cathode and multi-cavity anode structure fabricated in the manner Well known in the art.
  • External magnets 3 and 4 abut the envelope and are substantially U-shaped to provide the magnetic field essential to the operation of devices in the illustrative class.
  • Further conventional components include an output coupling flange 3,173,048 Patented Mar. 9, 1965 2, cathode-heater tubular extension 5, cooling fins 6 and tuner assembly 7 having a driving gear 8.
  • a single cell getter ion vacuum pump apparatus 9 is externally appended and centrally located within the space defined between the parallel arms of the magnet 4. Pump 9 communicates with the interior of the tube body 1 by tribulation 12. While the pump apparatus has been shown positioned within the space defined by magnet 4, magnet 3 may be utilized similarly. In fact two or more pumps may be provided if desired.
  • a cold cathode glow discharge is initiated and maintained between an anode16 and a plurality of cathode plates 17 with a suitable positive voltage potential applied to the anode.
  • the cathode plates and envelope 18 are at ground potential.
  • the pumping elements are desirably fabricated of a reactive material, such as titanium and a magnetic field of at least 1,000 gauss or more is applied perpendicular to the cathode plates.
  • the electrons tend to flow to the anode due to the electric field and are forced into a spiral path by the presence of the strong magnetic field.
  • the greatly increased electron path length results in a high probability of collision between free electrons and gas molecules. These collisions produce gas ions and an avalanche of free electrons.
  • the free electrons in turn collide with other gas molecules to free ions and electrons.
  • the positively charged gas ions then bombard the titanium cathode plates from which titanium atoms are sputtered out and deposited onto the anode. There the freshly sputtered titanium atoms combine chemically with the active gas atoms to form stable compounds. Chemically inert gas atoms are also removed by ion burial in the cathode and entrapment on the anode.
  • the external magnetic circuit was calculated to provide a leakage magnetic field of 1,000-1,500 gauss in the area indicated by 15. With this field available, a single anode cell getter ion vacuum pump 9 was positioned relatively close to the cooling fins 6, since this is the point of greatest magnetic intensity.
  • the connecting tubulation 12 was 7 inch and the pumping speed achieved with a positive D.C. voltage supply of 1,000 to 4,000 volts applied to terminal 11 of extension 10 approached .2 liter per second.
  • the overall packaged tube is processed through all stages including evacuation utilizing conventional vacuum pumps appropriately connected by means of tubulation 13 until a vacuum of approximately 10 Hg is measured.
  • the tubulation is then tipped-off and sealed as at 14 to provide a complete operable tube with an appended external pump permanently incorporated.
  • One interesting feature of the getter ion vacuum pump is the fact that pump current bears a linear relation to the density of the gas molecules within the envelope. Hence by a direct reading of pump current by means of a sensitive micro-ammeter the gaseous content of the internal atmosphere will be immediately indicated.
  • the external pump may be activated to restore the original vacuum simply by connecting to a positive DC. voltage supply.
  • readings indicating a pressure of 10* or 10' mm. Hg require immediate attention to lower these values to 10- mm. Hg. or better.
  • Pump life is another important feature since commercially available getter ion pumps utilizing titanium components have almost interminable life running into hundreds of thousands of hours.
  • a high vacuum electron discharge device comprising: an evacuable envelope, magnetic means mounted externally of said envelope for producing a magnetic field which threads said envelope with lines of force required for operation of said device, and a leakage field; a getter ion vacuum pump apparatus of the type adapted to produce an electrical glow discharge when energized positioned within said leakage field; and, tubulation means connecting said pump apparatus with said envelope.
  • a high vacuum electron discharge device according to claim 1 wherein said pump apparatus comprises a cylinder with its axis aligned coaxially With the lines of force of said leakage magnetic field.
  • a high vacuum electron discharge device according to claim 1 wherein said pump apparatus comprises an internal cathode of a reactive material and an anode structure having at least one glow discharge passageway.
  • said external magnetic means comprise substantially U-shaped permanent magnets with the open-ended pole pieces abutting said envelope.

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  • Electron Tubes For Measurement (AREA)
  • Particle Accelerators (AREA)
US93399A 1961-03-06 1961-03-06 Ion vacuum pump for magnetrons controlled for leakage of magnetron magnet Expired - Lifetime US3173048A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DENDAT1248819D DE1248819B (enrdf_load_stackoverflow) 1961-03-06
US93399A US3173048A (en) 1961-03-06 1961-03-06 Ion vacuum pump for magnetrons controlled for leakage of magnetron magnet
GB8450/62A GB928012A (en) 1961-03-06 1962-03-05 High vacuum electron discharge device
FR890221A FR1316966A (fr) 1961-03-06 1962-03-06 Dispositif à décharge électronique à vide poussé

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US93399A US3173048A (en) 1961-03-06 1961-03-06 Ion vacuum pump for magnetrons controlled for leakage of magnetron magnet

Publications (1)

Publication Number Publication Date
US3173048A true US3173048A (en) 1965-03-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
US93399A Expired - Lifetime US3173048A (en) 1961-03-06 1961-03-06 Ion vacuum pump for magnetrons controlled for leakage of magnetron magnet

Country Status (3)

Country Link
US (1) US3173048A (enrdf_load_stackoverflow)
DE (1) DE1248819B (enrdf_load_stackoverflow)
GB (1) GB928012A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3300678A (en) * 1963-05-15 1967-01-24 Capitol Records Traveling wave tube with plural pole piece assemblies defining a vacuum sealed tube body and particular collector structure
JPS51138061U (enrdf_load_stackoverflow) * 1975-04-28 1976-11-08
JPS51138063U (enrdf_load_stackoverflow) * 1975-04-30 1976-11-08
JPS52114652U (enrdf_load_stackoverflow) * 1976-02-27 1977-08-31
US20110018545A1 (en) * 2008-02-28 2011-01-27 Inficon Gmbh Helium sensor

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2282401A (en) * 1938-01-06 1942-05-12 Rca Corp Electrical vacuum pump
US2507653A (en) * 1942-02-28 1950-05-16 Cornell Res Foundation Inc Ionized particle separator
US2726805A (en) * 1953-01-29 1955-12-13 Ernest O Lawrence Ion pump
US2765014A (en) * 1953-09-21 1956-10-02 Hans Klepper Construction element for use as a pillar, strut, brace or other stiffening member
US2899604A (en) * 1956-03-28 1959-08-11 Magnetrons
US2980317A (en) * 1957-02-27 1961-04-18 Leybolds Nachfolger E Vacuum device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2282401A (en) * 1938-01-06 1942-05-12 Rca Corp Electrical vacuum pump
US2507653A (en) * 1942-02-28 1950-05-16 Cornell Res Foundation Inc Ionized particle separator
US2726805A (en) * 1953-01-29 1955-12-13 Ernest O Lawrence Ion pump
US2765014A (en) * 1953-09-21 1956-10-02 Hans Klepper Construction element for use as a pillar, strut, brace or other stiffening member
US2899604A (en) * 1956-03-28 1959-08-11 Magnetrons
US2980317A (en) * 1957-02-27 1961-04-18 Leybolds Nachfolger E Vacuum device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3300678A (en) * 1963-05-15 1967-01-24 Capitol Records Traveling wave tube with plural pole piece assemblies defining a vacuum sealed tube body and particular collector structure
JPS51138061U (enrdf_load_stackoverflow) * 1975-04-28 1976-11-08
JPS51138063U (enrdf_load_stackoverflow) * 1975-04-30 1976-11-08
JPS52114652U (enrdf_load_stackoverflow) * 1976-02-27 1977-08-31
US20110018545A1 (en) * 2008-02-28 2011-01-27 Inficon Gmbh Helium sensor
US8633704B2 (en) * 2008-02-28 2014-01-21 Inficon Gmbh Helium sensor

Also Published As

Publication number Publication date
DE1248819B (enrdf_load_stackoverflow) 1967-08-31
GB928012A (en) 1963-06-06

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