US3495116A - Pump arrangement with auxiliary cathode for electrical discharge vessels - Google Patents

Pump arrangement with auxiliary cathode for electrical discharge vessels Download PDF

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Publication number
US3495116A
US3495116A US560471A US3495116DA US3495116A US 3495116 A US3495116 A US 3495116A US 560471 A US560471 A US 560471A US 3495116D A US3495116D A US 3495116DA US 3495116 A US3495116 A US 3495116A
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United States
Prior art keywords
cathode
impact
electrode
pump arrangement
vessel
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Expired - Lifetime
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US560471A
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English (en)
Inventor
Gerhard Horn
Helmut Katz
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Siemens AG
Siemens Corp
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Siemens Corp
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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
    • H01J41/12—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps
    • H01J41/14—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps with ionisation by means of thermionic cathodes
    • H01J41/16—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps with ionisation by means of thermionic cathodes using gettering substances

Definitions

  • the pump includes an auxiliary electron discharge path comprising a dispenser cathode of the metal capillary type for producing electrons Which are directed to impinge upon the surface of an impact electrode means.
  • the impact electrode may be of zirconium or titanium and is heated by the electron impact on the surface thereof.
  • the invention relates to a pump arrangement, utilizing an auxiliary cathode, for electrical discharge vessels, in particular power tubes.
  • the auxiliary cathode consists of an indirectly heated storage cathode, in particular of an MK cathode, and that one or several attached operating electrodes are provided, in particular in the form of anodes, especially constructed to achieve a considerable electron impact, with the surface of said electrodes being entirely or partially coated and/ or primarily consisting of getter material such as zirconium or the like.
  • the invention is based upon the knowledge that electrodes made of a high melting metal with a zirconium or other suitable coating produce an excellent gettering action when they are brought to a sufficiently high temperature that sufficiently intensive appropriates chemical reaction between the zirconium and the gases to be gettered takes place, whereby such gases are then bound 3,495,116 Patented Feb. 10, 1970 with the zirconium. It is advantageous in this arrangement if some of several operating electrodes reach different temperatures during operation, or if only one operating electrode is present, the cross section of the generally disk-shaped electrode involved is proportioned to have a varying thickness, for example, becoming thinner toward its periphery, in such a Way that during electron impact different temperatures exist at the same electrode for the individual gases to be gettered.
  • the pump is constructed as an auxiliary discharge system to be additionally installed.
  • the pump is provided with a concentric structure so that it readily can be additionally installed in a discharge vessel. Its efficient pump effect is based upon the excellent qualities of the storage cathode (auxiliary supply cathode) utilized for this purpose, in particular an MK cathode.
  • Such a cathode assures a reliably long life, and in addition has a sutficient current capacity that even when the heater and accelerating voltage requirements are small, the required electrodes with large surfaces may be brought to a desired glow and that, in addition to this feature, by the relatively large discharge current density, a sufficient ionization of the remaining gases is so assured that their binding as an ion to the appropriate getter is accelerated.
  • the discharge can, especially advantageously, take place in the range of saturation.
  • FIG. 1 illustrates an electron discharge system with the cathode portion illustrated in elevation and the anode in transverse section;
  • FIG. 2 is a similar figure of one embodiment of the invention utilizing a plurality of anode electrodes
  • FIG. 3 is a similar figure of an embodiment utilizing two electron emitting surfaces.
  • FIG. 4 illustrates an alternate arrangement wherein the operational electrode is concave.
  • the MK cathode 1 of cylindrical shape and provided with an emission end surface is cooperable with a disk-shaped operating electrode 2 of molybdenum, operatively disposed in opposition to the cathode, and provided by known methods with a coating of zirconium which may extend on either or both sides of the disk. If a suitable voltage is maintained between the two electrodes, as a result of the impact of the electron discharge from the cathode upon the molybdenum disk, sufficient heat will be generated to effect a desired glow in such a way that the central portion of the disk possesses the highest temperature, which then gradually diminishes towards the periphery of the disk.
  • This distribution may be adjusted, for example, by selection of an appropriate accelerating voltage, and also by variation of the cross section of the molybdenum disk, in such a way that for the gettering of certain gases, the desired temperatures are achieved.
  • an auxiliary electrode 3 is additionally provided, which is in the form of an apertured diaphragm.
  • This electrode is formed with a central opening, the diameter of which is smaller than that of the :athode.
  • the customary other operating electrode is disposed behind this auxiliary electrode, both electrodes, however, being connected to different high positive po- ;entials relative to the cathode.
  • the liaphragm-shaped first operating electrode receives a part of the discharge current and thereby is brought to a glow by electron impact.
  • the portion of the current pass- .ng through the diaphragm opening strikes the actual, principal operating electrode and, according to the amount )f such current, brings this electrode to a higher or lower )perating temperature.
  • the potential difference between lllCh two operating electrodes provides the feature that my remaining gases present in the space between these we electrodes are ionized because of the occurring elec- .r0r1 discharge, which in particular is of high density, and n addition thereto, the ions formed during such process '6 accelerated towards the two electrodes, which, for :xample, are covered with zirconium, and thus bound hereto.
  • the MK :athode is so constructed that its two end surfaces are :onstructed in the form of respective emission material :arrier disks 11 and 12 so that emission takes place at oth ends.
  • the individual )perating electrodes are in this example likewise heated y electron impact to different high temperatures so that tn excellent getter effect is obtained for the individual 'emaining gases requiring different getter conditions.
  • the VIK cathode emitting on both ends may, in an advanageous development of the described pump arrangement, also be utilized in such a way that one of its emission faces s operable for beam production in the actual tube system tnd that only the other emitting end surface is utilized or the described pump operation.
  • FIG. 4 illustrates an alternate arrangement of the pres- :nt invention wherein the impact electrode 32 is concave o somewhat surround the cathode 31. Additionally, the :athode 31 may be convex.
  • the invention is not restricted to the illustrated exam- )le of construction. Many more possibilities of construcion can be achieved which have not been individually llustrated.
  • getter substances as for example titanium, may ikewise be successfully utilized instead of the mentioned irconium which has a known excellent getter effect.
  • a pump arrangement for operation within an elec- 'ical discharge vessel for preventing gas accumulation 'ithin the vessel comprising: a cathode, said athode being a metal capillary cathode for emitting a igh density electron stream; impact electrode means ositioned adjacent said cathode and having an impact irface for receiving the electrons emitted by said cathde; and a getter material secured to said impact elec- 'ode means, said impact surface free of getter material, hereby, electron impingement on said impact surface ill cause said impact electrode means to become heated ifficiently to enable said getter material to absorb gases hich may exist within the vessel.
  • a pump arrangement for operation within an elecical discharge vessel for preventing gas accumulation ithin the vessel comprising: a cathode, said cathode being a metal capillary cathode for emitting a high density electron stream; impact electrode means positioned adjacent said cathode and having an impact surface for receiving the electrons emitted by said cathode and including first and second electrodes, said second electrode being apertured and positioned between said cathode and said first electrode; and a getter material secured to said impact electrode means, whereby, electron impingement on said impact surface will cause said impact electrode means to become heated sufficiently to enable said getter material to absorb gases which may exist Within the vessel.
  • a pump arrangement for operation within an electrical discharge vessel for preventing gas accurnmulation within the vessel comprising: a cathode, said cathode being a metal capillary cathode for emitting a high density electron stream; impact electrode means including a plurality of individual electrodes, said impact electrode means being positioned adjacent said cathode and having an impact surface for receiving the electrons emitted by said cathode; and a getter materialsecured to said impact electrode means, the individual electrodes arranged with respect to said cathode whereby, electron impingement on said impact surface will cause said impact electrode means to become sufficiently heated with the individual electrodes thereof being heated to different temperatures to enable said getter material to absorb gases which may exist within the vessel.
  • a pump arrangement for operation within an electrical discharge vessel for preventing gas accurnmulation within the vessel comprising: a cathode, said cathode being a metal capillary cathode for emitting a high density electron stream; impact electrode means positioned adjacent said cathode and having a non-uniform cross-section and an impact surface for receiving the electrons emitted by said cathode; and a getter material secured to said impact electrode means, whereby, electron impingement on said impact surface will produce a temperature gradient across said impact electrode means sufficient to enable said getter material to absorb gases Which may exist within the vessel.
  • a pump arrangement for operation within an electrical discharge vessel for preventing gas accumulation within the vessel comprising: a cathode, said cathode being a metal capillary cathode for emitting a high density electron stream; and impact electrode means positioned adjacent said cathode and having an impact surface for receiving the electrons emitted by said cathode, said impact electrode means consisting substantially of getter material, whereby electron impingement on said impact surface will cause said impact electrode means to become sufiiciently heated to enable said getter material to absorb gases which may exist within the vessel.
  • a pump arrangement for operation within an electrical discharge vessel for preventing gas accumulation within the vessel comprising: a cathode, said cathode being a metal capillary cathode for emitting a high density electron stream; impact electrode means positioned adjacent said cathode and having an impact surface for receiving the electrons emitted by said cathode, said impact electrode means including a first electrode formed by a circular sheet of molybdenum and a second electrode formed by an apertured circular sheet of molybdenum and positioned between said cathode and said first electrode; and a getter material secured to said impact electrode means, whereby, electron impingement on said impact surface will cause said impact electrode means to become heated sufficiently to enable said getter material to absorb gases which may exsit Within the vessel.

Landscapes

  • Electron Tubes For Measurement (AREA)
  • Discharge Lamp (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US560471A 1965-06-30 1966-06-27 Pump arrangement with auxiliary cathode for electrical discharge vessels Expired - Lifetime US3495116A (en)

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Application Number Priority Date Filing Date Title
DES0097898 1965-06-30

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US3495116A true US3495116A (en) 1970-02-10

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US (1) US3495116A (cs)
DE (1) DE1539135A1 (cs)
GB (1) GB1146490A (cs)
NL (1) NL6609143A (cs)
SE (1) SE300281B (cs)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3582702A (en) * 1968-04-04 1971-06-01 Philips Corp Thermionic electron-emissive electrode with a gas-binding material

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2547200A (en) * 1945-09-15 1951-04-03 Hartford Nat Bank & Trust Co Getter structure for electric discharge tubes
US2741717A (en) * 1951-06-14 1956-04-10 Siemens Ag Dispenser type cathode having gettercoated parts
US2972697A (en) * 1958-06-26 1961-02-21 Prd Electronics Inc Molecular beam apparatus of the maser type
US3264510A (en) * 1963-08-27 1966-08-02 Leighton E Griffiths Degassing of cathode ray tubes
US3299311A (en) * 1962-05-09 1967-01-17 Siemens Ag Velocity modulated electron tube with integrated focusing and getter pump systems, the pump having multiple getter-coated electrodes
US3319107A (en) * 1964-10-12 1967-05-09 Varian Associates Plural rod getter between the heat source and heat sink of a vacuum tube

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2547200A (en) * 1945-09-15 1951-04-03 Hartford Nat Bank & Trust Co Getter structure for electric discharge tubes
US2741717A (en) * 1951-06-14 1956-04-10 Siemens Ag Dispenser type cathode having gettercoated parts
US2972697A (en) * 1958-06-26 1961-02-21 Prd Electronics Inc Molecular beam apparatus of the maser type
US3299311A (en) * 1962-05-09 1967-01-17 Siemens Ag Velocity modulated electron tube with integrated focusing and getter pump systems, the pump having multiple getter-coated electrodes
US3264510A (en) * 1963-08-27 1966-08-02 Leighton E Griffiths Degassing of cathode ray tubes
US3319107A (en) * 1964-10-12 1967-05-09 Varian Associates Plural rod getter between the heat source and heat sink of a vacuum tube

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3582702A (en) * 1968-04-04 1971-06-01 Philips Corp Thermionic electron-emissive electrode with a gas-binding material

Also Published As

Publication number Publication date
DE1539135A1 (de) 1969-08-28
SE300281B (cs) 1968-04-22
GB1146490A (en) 1969-03-26
NL6609143A (cs) 1967-01-02

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