EP0009261A1 - Storage cathode, particularly metal capillary cathode - Google Patents

Storage cathode, particularly metal capillary cathode Download PDF

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Publication number
EP0009261A1
EP0009261A1 EP79103624A EP79103624A EP0009261A1 EP 0009261 A1 EP0009261 A1 EP 0009261A1 EP 79103624 A EP79103624 A EP 79103624A EP 79103624 A EP79103624 A EP 79103624A EP 0009261 A1 EP0009261 A1 EP 0009261A1
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EP
European Patent Office
Prior art keywords
cathode
emission
carrier disk
work function
storage
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.)
Ceased
Application number
EP79103624A
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German (de)
French (fr)
Inventor
Hinrich Dr.rer.nat. Dipl.-Phys. Heynisch
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.)
Siemens AG
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Siemens AG
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Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0009261A1 publication Critical patent/EP0009261A1/en
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
    • H01J1/28—Dispenser-type cathodes, e.g. L-cathode

Definitions

  • the invention relates to a storage cathode, in particular a metal capillary cathode, for electrical discharge vessels with an end-face porous emissive carrier disk made of refractory metal, such as tungsten.
  • Cathodes for electrical discharge vessels in which emission substances from an emission substance supply through fine openings of a porous emission substance carrier covering this, made of in particular porous sintered high-melting metal, such as e.g. Tungsten, migrate to the cathode surface and in which the supply of barium in the operation consists of barium oxide are known (DE-PS 12 17 503).
  • Such cathodes are e.g. used in traveling wave tubes and disc tubes.
  • the known supply cathodes have the disadvantage that, during operation, electrons are not only emitted from the end face but also from the side faces.
  • the invention has for its object to provide a supply cathode, in particular MK cathode, in which the lateral emission (interference emission) is prevented.
  • a supply cathode, in particular MK cathode of the type mentioned at the outset according to the invention that the emission carrier plate has a non-porous outer surface with a higher electron work function than the outer active surface of the emission carrier plate.
  • the outer surface of the emission carrier plate preferably has an electron work function> 3 eV and the outer active surface of the emission carrier plate has an electron work function of approximately 2 eV.
  • the outer surface of the emission carrier plate preferably consists of a thin-walled cylinder made of tantalum or molybdenum.
  • the outer surface area expediently has a wall thickness of 5 to 10 / um.
  • the outer circumferential surface of the emission carrier plate is made of carbon or contains carbon.
  • a supply cathode according to the invention has the essential advantage that the side surface of the cathode emits practically no electrons at a temperature which is optimal for a supply cathode (approx. 1100 ° C. p ) and thus the undesired lateral interference emission is prevented.
  • the supply cathode shown purely schematically in section in the figure has an emission substance carrier disk 2.
  • a very thin-walled cylinder is drawn over the cylindrical outer surface, which preferably consists of tantalum or molybdenum and expediently has a wall thickness of 5 ⁇ m to 10 ⁇ m.
  • this cylinder forms the non-porous outer jacket surface 1, which can advantageously also be realized in that the material of the outer jacket surface 1 is also pressed in during the pressing process of the emission substance carrier disk 2.
  • the non-porous outer surface 1 has a work function> 4 eV when using tantalum or molybdenum and a work function> 5 eV when using platinum.
  • the outer active surface 3 (emission surface) of the emission carrier disk 2 has a work function of approximately 2 eV.
  • the surface 3 of the porous emissive carrier disk 2, for example made of tungsten, is active when the emis Sionsstoffvorrat, for example barium, reaches the surface 3 in operation through the fine openings of the emission carrier and together with its material determines the work function of this surface (emission surface).

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  • Solid Thermionic Cathode (AREA)

Abstract

Die Erfindung bezieht sich auf eine Vorratskathode, insbesondere Metall-Kapillar-Kathode, für elektrische Entladungsgefässe mit einer stirnseitigen porösen Emissionsstoffträgerscheibe (2) aus hochschmelzendem Metall. Bei dieser Vorratskathode soll die seitliche Emission (Störemission) verhindert werden. Die Erfindung sieht hierzu vor, dass die Emissionsstoffträgerscheibe (2) eine nicht poröse Aussenmantelfläche (1) mit einer höheren Elektronenaustrittsarbeit als die äussere aktive Oberfläche (3) der Emissionsstoffträgerscheibe (2) aufweist. Eine erfindungsgemässe Vorratskathode wird als MK-Kathode bei Wanderfeldröhren verwendet.The invention relates to a supply cathode, in particular a metal capillary cathode, for electrical discharge vessels with a porous emissive carrier disk (2) made of refractory metal on the end face. Lateral emission (interference emission) is to be prevented with this supply cathode. For this purpose, the invention provides that the emission carrier plate (2) has a non-porous outer surface (1) with a higher electron work function than the outer active surface (3) of the emission carrier plate (2). A supply cathode according to the invention is used as an MK cathode in traveling wave tubes.

Description

Die Erfindung betrifft eine Vorratskathode, insbesondere Metall-Kapillar-Kathode, für elektrische Entladungsgefäße mit einer stirnseitigen porösen Emissionsstoffträgerscheibe aus hochschmelzendem Metall, wie Wolfram.The invention relates to a storage cathode, in particular a metal capillary cathode, for electrical discharge vessels with an end-face porous emissive carrier disk made of refractory metal, such as tungsten.

Kathoden für elektrische Entladungsgefäße, bei denen im Betrieb Emissionssubstanzen aus einem Emissionsstoffvorrat durch feine Öffnungen eines diesen bedeckenden porösen Emissionsstoffträgers aus insbesondere porös gesintertem hochschmelzenden Metall, wie z.B. Wolfram, zur Kathodenoberfläche hin wandern und bei denen der im Betrieb Barium abgebende Vorrat aus Bariumoxid besteht, sind bekannt (DE-PS 12 17 503).Cathodes for electrical discharge vessels, in which emission substances from an emission substance supply through fine openings of a porous emission substance carrier covering this, made of in particular porous sintered high-melting metal, such as e.g. Tungsten, migrate to the cathode surface and in which the supply of barium in the operation consists of barium oxide are known (DE-PS 12 17 503).

Derartige Kathoden werden z.B. in Wanderfeldröhren und Scheibenröhren verwendet.Such cathodes are e.g. used in traveling wave tubes and disc tubes.

Die bekannten Vorratskathoden haben allerdings den Nachteil, daß beim Betrieb nicht nur aus der Stirnfläche Elektronen emittiert werden sondern auch aus den Seitenflächen.However, the known supply cathodes have the disadvantage that, during operation, electrons are not only emitted from the end face but also from the side faces.

Der Erfindung liegt die Aufgabe zugrunde, eine Vorratskathode, insbesondere MK-Kathode, zu schaffen, bei der die seitliche Emission (Störemission) verhindert ist. Zur Lösung dieser Aufgabe ist bei einer Vorratskathode, insbesondere MK-Kathode, der eingangs genannten Art gemäß der Erfindung vorgesehen, daß die Emissionsstoffträgerscheibe eine nicht poröse Außenmantelfläche mit einer höheren Elektronenaustrittsarbeit als die äußere aktive Oberfläche der Emissionsstoffträgerscheibe aufweist. Dabei haben vorzugsweise die AuBenmantelfläche der Emissionsstoffträgerscheibe eine Elektronenaustrittsarbeit >3 eV und die äußere aktive-Oberfläche der Emissionsstoffträgerscheibe eine Elektronenaustrittsarbeit von ca. 2 eV.The invention has for its object to provide a supply cathode, in particular MK cathode, in which the lateral emission (interference emission) is prevented. To achieve this object, it is provided in a supply cathode, in particular MK cathode, of the type mentioned at the outset according to the invention that the emission carrier plate has a non-porous outer surface with a higher electron work function than the outer active surface of the emission carrier plate. The outer surface of the emission carrier plate preferably has an electron work function> 3 eV and the outer active surface of the emission carrier plate has an electron work function of approximately 2 eV.

Die Außenmantelfläche der Emissionsstoffträgerscheibe besteht vorzugsweise aus einem dünnwandigen Zylinder aus Tantal oder Molybdän.The outer surface of the emission carrier plate preferably consists of a thin-walled cylinder made of tantalum or molybdenum.

Es kann auch vorteilhaft sein, das Metall der Außenmantelfläche beim Preßvorgang der Emissionsstoffträgerscheibe gleich mit in diese Scheibe einzupressen.It can also be advantageous to press the metal of the outer lateral surface into this disk at the same time as the emission substance carrier disk is pressed.

Die Außenmantelfläche hat zweckmäßig eine Wandstärke von 5 bis 10/um.The outer surface area expediently has a wall thickness of 5 to 10 / um.

Gemäß einer weiteren Ausgestaltung der Erfindung besteht die Außenmantelfläche der Emissionsstoffträgerscheibe aus Kohlenstoff oder enthält Kohlenstoff.According to a further embodiment of the invention, the outer circumferential surface of the emission carrier plate is made of carbon or contains carbon.

Eine erfindungsgemäße Vorratskathode hat den wesentlichen Vorteil, daß die seitliche Oberfläche der Kathode bei einer Temperatur, wie sie für eine Vorratskathode optimal ist (ca. 1100 °Cp), praktisch keine Elektronen emittiert und damit die unerwünschte seitliche Störemission verhindert ist.A supply cathode according to the invention has the essential advantage that the side surface of the cathode emits practically no electrons at a temperature which is optimal for a supply cathode (approx. 1100 ° C. p ) and thus the undesired lateral interference emission is prevented.

An Hand der Figur der Zeichnung soll die Erfindung nachstehend mit weiteren Merkmalen näher erläutert werden. Teile, die nicht unbedingt zum Verständnis der Erfindung beitragen, sind darin weggelassen.Based on the figure of the drawing, the invention will be explained in more detail below with further features. Parts that do not necessarily contribute to an understanding of the invention are omitted.

Die in der Figur rein schematisch im Schnitt dargestellte Vorratskathode weist eine Emissionsstoffträgerscheibe 2 auf. Über die zylindrische Außenfläche ist ein sehr dünnwandiger Zylinder gezogen, der vorzugsweise aus Tantal oder Molybdän besteht und zweckmäßig eine Wandstärke von 5/um bis 10/um hat. Dieser Zylinder bildet in diesem Ausführungsbeispiel die nicht poröse Außenmantelfläche 1, die vorteilhaft aber auch dadurch realisiert sein kann, daß das Material der Außenmantelfläche 1 beim Preßvorgang der Emissionsstoffträgerscheibe 2 mit eingepreßt wird.The supply cathode shown purely schematically in section in the figure has an emission substance carrier disk 2. A very thin-walled cylinder is drawn over the cylindrical outer surface, which preferably consists of tantalum or molybdenum and expediently has a wall thickness of 5 μm to 10 μm. In this exemplary embodiment, this cylinder forms the non-porous outer jacket surface 1, which can advantageously also be realized in that the material of the outer jacket surface 1 is also pressed in during the pressing process of the emission substance carrier disk 2.

Die nicht poröse Außenmantelfläche 1 hat, z.B. bei der Verwendung von Tantal oder Molybdän, eine Austrittsarbeit > 4 eV und bei der Verwendung von Platin eine Austrittsarbeit > 5 eV. Dagegen hat die äußere aktive Oberfläche 3 (Emissionsfläche) der Emissionsstoffträgerscheibe 2 eine Austrittsarbeit von ca. 2 eV. Die Oberfläche 3 der porösen, z.B. aus Wolfram bestehenden Emissionsstoffträgerscheibe 2 ist dann aktiv, wenn der Emissionsstoffvorrat, z.B. Barium, im Betrieb durch die feinen Öffnungen des Emissionsstoffträgers an die Oberfläche 3 gelangt und zusammen mit dessen Material die Austrittsarbeit dieser Oberfläche (Emissionsfläche) bestimmt.The non-porous outer surface 1 has a work function> 4 eV when using tantalum or molybdenum and a work function> 5 eV when using platinum. In contrast, the outer active surface 3 (emission surface) of the emission carrier disk 2 has a work function of approximately 2 eV. The surface 3 of the porous emissive carrier disk 2, for example made of tungsten, is active when the emis Sionsstoffvorrat, for example barium, reaches the surface 3 in operation through the fine openings of the emission carrier and together with its material determines the work function of this surface (emission surface).

Claims (6)

1. Vorratskathode, insbesondere Metall-Kapillar-Kathode, für elektrische Entladungsgefäße mit einer stirnseitigen porösen Emissionsstoffträgerscheibe aus hochschmelzendem Metall, wie Wolfram, dadurch gekennzeichnet , daß die Emissionsstoffträgerscheibe (2) eine nicht poröse Außenmantelfläche (1) mit einer höheren Elektronenaustrittsarbeit als die äußere aktive Oberfläche (3) der Emissionsstoffträgerscheibe (2) aufweist.1. storage cathode, in particular metal capillary cathode, for electrical discharge vessels with an end-face porous emissive carrier disk made of refractory metal, such as tungsten, characterized in that the emissive carrier disk (2) has a non-porous outer surface (1) with a higher electron work function than the outer active Surface (3) of the emission carrier plate (2). 2. Vorratskathode nach Anspruch 1, dadurch gekennzeichnet , daß die Außenmantelfläche (1) der Emissionsstoffträgerscheibe (2) eine Elektronenaustrittsarbeit > 3 eV und die äußere aktive Oberfläche (3) der Emissionsstoffträgerscheibe (2) eine Elektronenaustrittsarbeit von ca. 2 eV haben.2. Storage cathode according to claim 1, characterized in that the outer surface (1) of the emission carrier disk (2) has an electron work function> 3 eV and the outer active surface (3) of the emission carrier disk (2) have an electron work function of about 2 eV. 3. Vorratskathode nach Anspruch 1 oder 2, dadurch gekennzeichnet , daß die Außenmantelfläche (1) der Emissionsstoffträgerscheibe (2) aus einem dünnwandigen Zylinder aus Tantal oder Molybdän besteht.3. Storage cathode according to claim 1 or 2, characterized in that the outer surface (1) of the emissive carrier disk (2) consists of a thin-walled cylinder made of tantalum or molybdenum. 4. Vorratskathode nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet , daß das Metall der Außenmantelfläche (1) beim Preßvorgang der Emissionsstoffträgerscheibe (2) mit eingepreßt ist.4. Storage cathode according to one of claims 1 to 3, characterized in that the metal of the outer surface (1) is pressed in during the pressing process of the emission carrier disk (2). 5. Vorratskathode nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet , daß die Außenmantelfläche (1) eine Wandstärke von 5 bis 10/um hat.5. Storage cathode according to one of claims 1 to 4, characterized in that the outer surface (1) has a wall thickness of 5 to 10 / um. 6. Vorratskathode nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet , daß die Außenmantelfläche (1) aus Kohlenstoff besteht oder Kohlenstoff enthält.6. supply cathode according to one of claims 1 to 5, characterized in that the outer surface (1) consists of carbon or contains carbon.
EP79103624A 1978-09-27 1979-09-24 Storage cathode, particularly metal capillary cathode Ceased EP0009261A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2842079 1978-09-27
DE19782842079 DE2842079A1 (en) 1978-09-27 1978-09-27 SUPPLY CATHODE, ESPECIALLY METAL CAPILLARY CATHODE

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EP0009261A1 true EP0009261A1 (en) 1980-04-02

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EP79103624A Ceased EP0009261A1 (en) 1978-09-27 1979-09-24 Storage cathode, particularly metal capillary cathode

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EP (1) EP0009261A1 (en)
DE (1) DE2842079A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2537338A1 (en) * 1982-12-03 1984-06-08 Thomson Csf Thermoelectronic cathode and method of producing such a cathode.
GB2173943A (en) * 1985-04-18 1986-10-22 Noblelight Limited Improvements in and relating to cathodes
WO2015166448A1 (en) 2014-04-30 2015-11-05 L'oreal Composition comprising microcapsules containing silicone elastomer

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4587455A (en) * 1982-10-12 1986-05-06 Hughes Aircraft Company Controlled porosity dispenser cathode
DE3600480A1 (en) * 1986-01-10 1987-07-16 Licentia Gmbh METHOD FOR PRODUCING A POROUS PRESSURE
US8311186B2 (en) * 2007-12-14 2012-11-13 Schlumberger Technology Corporation Bi-directional dispenser cathode

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GB767718A (en) * 1952-10-28 1957-02-06 Vickers Electrical Co Ltd "improvements relating to electron emissive cathodes"
US2813220A (en) * 1954-12-06 1957-11-12 Philips Corp Indirectly heated cathode
DE1027329B (en) * 1956-12-15 1958-04-03 Siemens Ag Process for the production of an indirectly heated storage cathode in the manner of a traveling cathode
US2972078A (en) * 1959-01-23 1961-02-14 Philips Corp Carburization of dispenser cathodes
FR1283628A (en) * 1960-03-14 1962-02-02 Philips Nv Welding assembly of a porous body and a support
DE1181824B (en) * 1953-02-16 1964-11-19 Philips Nv Process for the production of a supply cathode for electrical discharge tubes
US3229147A (en) * 1961-09-01 1966-01-11 Gen Electric Thermionic emitter and method of making same
DE1217503B (en) * 1964-12-02 1966-05-26 Siemens Ag Storage cathode for electrical discharge vessels
DE1257980B (en) * 1966-05-20 1968-01-04 Telefunken Patent Supply cathode and process for their manufacture
AT270821B (en) * 1966-07-01 1969-05-12 Philips Nv Process for the production of a supply cathode consisting of a porous sintered tungsten body impregnated with aluminates
DE2054698A1 (en) * 1969-11-21 1971-11-18 Philips Nv A method of making a supply cathode and a cathode made by this method
DE1934067B2 (en) * 1969-07-04 1972-08-31 Siemens AG, 1000 Berlin u. 8000 München LARGE DIMENSION OF STORAGE CATHOD AND METHOD FOR MANUFACTURING IT
DE2604765B2 (en) * 1975-02-21 1977-07-21 N V Philips' Gloeilampenfabrieken, Eindhoven (Niederlande) SUBSEQUENT DELIVERY CATHOD

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GB450035A (en) * 1935-05-07 1936-07-09 Ets Claude Paz & Silva Improvements in electrodes for high-pressure metallic vapour electric discharge tubes
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US2640950A (en) * 1951-06-06 1953-06-02 Atomic Energy Commission Point electron source
US3159461A (en) * 1958-10-20 1964-12-01 Bell Telephone Labor Inc Thermionic cathode
US3558966A (en) * 1967-03-01 1971-01-26 Semicon Associates Inc Directly heated dispenser cathode
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Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB767718A (en) * 1952-10-28 1957-02-06 Vickers Electrical Co Ltd "improvements relating to electron emissive cathodes"
DE1181824B (en) * 1953-02-16 1964-11-19 Philips Nv Process for the production of a supply cathode for electrical discharge tubes
US2813220A (en) * 1954-12-06 1957-11-12 Philips Corp Indirectly heated cathode
DE1027329B (en) * 1956-12-15 1958-04-03 Siemens Ag Process for the production of an indirectly heated storage cathode in the manner of a traveling cathode
US2972078A (en) * 1959-01-23 1961-02-14 Philips Corp Carburization of dispenser cathodes
FR1283628A (en) * 1960-03-14 1962-02-02 Philips Nv Welding assembly of a porous body and a support
US3229147A (en) * 1961-09-01 1966-01-11 Gen Electric Thermionic emitter and method of making same
DE1217503B (en) * 1964-12-02 1966-05-26 Siemens Ag Storage cathode for electrical discharge vessels
DE1257980B (en) * 1966-05-20 1968-01-04 Telefunken Patent Supply cathode and process for their manufacture
AT270821B (en) * 1966-07-01 1969-05-12 Philips Nv Process for the production of a supply cathode consisting of a porous sintered tungsten body impregnated with aluminates
DE1934067B2 (en) * 1969-07-04 1972-08-31 Siemens AG, 1000 Berlin u. 8000 München LARGE DIMENSION OF STORAGE CATHOD AND METHOD FOR MANUFACTURING IT
DE2054698A1 (en) * 1969-11-21 1971-11-18 Philips Nv A method of making a supply cathode and a cathode made by this method
DE2604765B2 (en) * 1975-02-21 1977-07-21 N V Philips' Gloeilampenfabrieken, Eindhoven (Niederlande) SUBSEQUENT DELIVERY CATHOD

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2537338A1 (en) * 1982-12-03 1984-06-08 Thomson Csf Thermoelectronic cathode and method of producing such a cathode.
GB2173943A (en) * 1985-04-18 1986-10-22 Noblelight Limited Improvements in and relating to cathodes
WO2015166448A1 (en) 2014-04-30 2015-11-05 L'oreal Composition comprising microcapsules containing silicone elastomer

Also Published As

Publication number Publication date
DE2842079A1 (en) 1980-04-03
US4310775A (en) 1982-01-12

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