US2499192A - Dispenser type cathode - Google Patents

Dispenser type cathode Download PDF

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Publication number
US2499192A
US2499192A US2402A US240248A US2499192A US 2499192 A US2499192 A US 2499192A US 2402 A US2402 A US 2402A US 240248 A US240248 A US 240248A US 2499192 A US2499192 A US 2499192A
Authority
US
United States
Prior art keywords
cathode
coil
dispenser type
type cathode
dense
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
US2402A
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English (en)
Inventor
James M Lafferty
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.)
General Electric Co
Original Assignee
General Electric Co
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 BE486753D priority Critical patent/BE486753A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US2402A priority patent/US2499192A/en
Priority to GB513/49A priority patent/GB685444A/en
Priority to FR979177D priority patent/FR979177A/fr
Application granted granted Critical
Publication of US2499192A publication Critical patent/US2499192A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/04—Manufacture of electrodes or electrode systems of thermionic cathodes
    • H01J9/042—Manufacture, activation of the emissive part
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J3/00—Details of electron-optical or ion-optical arrangements or of ion traps common to two or more basic types of discharge tubes or lamps
    • H01J3/02—Electron guns
    • H01J3/027—Construction of the gun or parts thereof

Definitions

  • My invention relates to dispenser type cathodes and methods of making the same.
  • Dispenser type cathodes have been manufactured in which a mesh of nickel or similar material is filled with a body of powdered electron emissive materialsuch as barium aluminate. The mesh is heated by conduction current to raise the powdered material to a temperature at which electrons are emitted.
  • a dispenser type cathode having relatively small cross sectional dimensions and it has been difficult toobtain satisfactory life from the cathode made in accordance with the prior art.
  • Prior art dispenser cathodes have also possessed rather low resistance so that a relatively large heating current is required.
  • I provide an improved dispenser type cathode and an improved method of making it which results in a very dense supply of electron emitting material and as a result insures adequate emission for a long period'of use.
  • Fig. l is an end elevational view of a cathode assembly embodyin my invention
  • Fig. 2 is a side elevational view of the cathode assembly shown in Fig. 1
  • Fig. 3 is a sectional View taken along the line 3-3 of Fig. 1
  • Fig. 4 is a perspective view of the cathode element of the assembly shown in Figs. 1-3
  • Fig. 5 is a perspective view of apparatus which may be used to advantage in the manufacture of cathodes in accordance with my invention.
  • the cathode proper comprises a helical wire coil l which may be wound on a suitable mandrel and 2 have any desired cross section.
  • the cross section of the illustrated embodiment is rectangular.
  • One side of therec tangle is curved inwardly or indented to pro; vide focusing of the electron beam emitted from the cathode surface.
  • vThe v coil I is supported within ,a channel-shaped shield and focusing member 3 by means of an intermediate channelshaped member including a central member -t of molybdenum or similar material which isco'ateed with a layer of alumina'5.
  • the side walls of the channel member 3 extend be yond the curved surface of the cathode and adapt the shield for its focusing function.
  • the cathode l and shield 3 may be supported in an electron discharge deviceysuch as an electronic ac celerator by the conductors 6 and l which may also provide means for supplying suitable potential to the shield 3.
  • the ends of the coil I. are closed by sheet metal members l2 which are secured"in.:position by welding or. ,by the ,wires I 3 which also bind the conductors '8. and
  • the cathode I and focusing shield 3 are positioned. within alarg er channel-shaped electrode l4 which'extends be; yond the innershield 3 andma'ybeutilized as an, accelerating electrode.
  • Suitable conductors l5 and iii are bonded to the electrode at for supporting it within the device in which it is to be used in insulated relation with respect to the cathode assembly and permitting suitable positive voltage to be applied to it when it is to be used as an accelerating electrode.
  • the cavity provided by the helical wire coil I is filled with a dense body of electron emittingmaterial designated by the numeral l1. While a number of materials may be used. such as barium hydroxide, thorium aluminate, or strontium aluminate, I have found that barium aluminate is particularly desirable.
  • the barium aluminate in granular form may be loaded into the interior of the coil and the coil heated to a temperature of approximately 1650 C. (preferably in an atmosphere of hydrogen) to melt the barium aluminate.
  • the barium aluminate forms a solid dense mass which only partially fill-s the interior of the coil l and the process is repeated until the coil is completely filled with a dense fused mass of solid barium aluminate.
  • the barium aluminate extends between adjacent turns of the coil sufficiently to insulate them with respect to one another and renders it possible for the coil l to function as a heater for the cathode.
  • the coil offers appreciably higher resistance than the mesh employed in the dispenser cathodes of the prior art and the increased resistance reduces the heating current requirements of'the cathode.
  • the boat is provided with an electrical heating "coil l9 which may be provided for melting the material.
  • the cathode is immersed in therec'eptacle I8 which is substantially filled with melted'barium aluminate. This is done preferably in an atmosphere of hydrogen or other reducing atmosphere.
  • the heater and core are removed from theboat 'and after the assembly has cooled sufiiciently "the emitting material forms a solid dense core.
  • the cathode of my invention when employing barium aluminate is operated at temperatures of 1200-1350" C. which is 'sufiicient'to provide for the gradual release of barium from the supply .p'rovided by the dense core.
  • a cathode having-these dimensions and manufactured inaccord'ancewith my invention is capable of delivering acurren't of 500 milliamperes, and it has been found to have a useful life exceeding 10,00'0hours.
  • a cathode comprising a helical wire coll providing a heater and a cast body of electron emitting material within said coil and extending between adjacent turns of said coil 'tofhold said turns in insulated relation.
  • a cathode comprising a helical coil of molybdenum wire and 'a'cast mass of barium 'aluminate within said coil and extending'between adjacent turns of said coil to hold said turns "in insulated relation.
  • a cathode including a hollow supportin coil which comprises the steps of loading the coil witha quantity of emitting material in granular form, melting the material to form a dense mass and repeating the loading and melting steps until the "coil is filled with a dense cast-bodyof emitting material.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Solid Thermionic Cathode (AREA)
US2402A 1948-01-15 1948-01-15 Dispenser type cathode Expired - Lifetime US2499192A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE486753D BE486753A (ja) 1948-01-15
US2402A US2499192A (en) 1948-01-15 1948-01-15 Dispenser type cathode
GB513/49A GB685444A (en) 1948-01-15 1949-01-07 Improvements relating to thermionic cathodes
FR979177D FR979177A (fr) 1948-01-15 1949-01-14 Cathode du type réactivable de façon continue

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US2402A US2499192A (en) 1948-01-15 1948-01-15 Dispenser type cathode

Publications (1)

Publication Number Publication Date
US2499192A true US2499192A (en) 1950-02-28

Family

ID=21700589

Family Applications (1)

Application Number Title Priority Date Filing Date
US2402A Expired - Lifetime US2499192A (en) 1948-01-15 1948-01-15 Dispenser type cathode

Country Status (4)

Country Link
US (1) US2499192A (ja)
BE (1) BE486753A (ja)
FR (1) FR979177A (ja)
GB (1) GB685444A (ja)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2719244A (en) * 1952-01-25 1955-09-27 Westinghouse Electric Corp Electrical discharge tube
US2786957A (en) * 1953-04-02 1957-03-26 Csf Emissive cathodes
US2925514A (en) * 1952-04-09 1960-02-16 Philips Corp Thermionic cathode
US3105917A (en) * 1960-02-11 1963-10-01 Philips Corp Electric discharge device comprising an activated cold cathode
US3113236A (en) * 1959-06-23 1963-12-03 Philips Corp Oxide dispenser type cathode
US3403282A (en) * 1964-12-02 1968-09-24 Siemens Ag Dispenser type cathode
US3405303A (en) * 1964-12-29 1968-10-08 Sylvania Electric Prod Arc discharge tube having an electrode which contains a light-emitting metal
US3706115A (en) * 1971-02-09 1972-12-19 Robert F Bleile Staple for sod and erosion control mattings
US4243624A (en) * 1979-05-21 1981-01-06 Exxon Research & Engineering Co. Method of making cathodes derived from ammonium-metal-chalcogen compounds

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1813704A (en) * 1928-06-26 1931-07-07 Westinghouse Lamp Co Cathode
US1817636A (en) * 1926-06-09 1931-08-04 Electrons Inc Electron emissive materials
US1946603A (en) * 1929-05-09 1934-02-13 Electrons Inc Cathode for electrical discharge devices
US2007926A (en) * 1930-10-21 1935-07-09 Sirian Lamp Co Light emitting unit
US2007932A (en) * 1930-08-23 1935-07-09 Sirian Lamp Co Surge arrester
US2107945A (en) * 1934-11-20 1938-02-08 Gen Electric Cathode structure
US2175345A (en) * 1935-07-12 1939-10-10 Gen Electric Electric gaseous discharge device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1817636A (en) * 1926-06-09 1931-08-04 Electrons Inc Electron emissive materials
US1813704A (en) * 1928-06-26 1931-07-07 Westinghouse Lamp Co Cathode
US1946603A (en) * 1929-05-09 1934-02-13 Electrons Inc Cathode for electrical discharge devices
US2007932A (en) * 1930-08-23 1935-07-09 Sirian Lamp Co Surge arrester
US2007926A (en) * 1930-10-21 1935-07-09 Sirian Lamp Co Light emitting unit
US2107945A (en) * 1934-11-20 1938-02-08 Gen Electric Cathode structure
US2175345A (en) * 1935-07-12 1939-10-10 Gen Electric Electric gaseous discharge device

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2719244A (en) * 1952-01-25 1955-09-27 Westinghouse Electric Corp Electrical discharge tube
US2925514A (en) * 1952-04-09 1960-02-16 Philips Corp Thermionic cathode
US2786957A (en) * 1953-04-02 1957-03-26 Csf Emissive cathodes
US3113236A (en) * 1959-06-23 1963-12-03 Philips Corp Oxide dispenser type cathode
US3105917A (en) * 1960-02-11 1963-10-01 Philips Corp Electric discharge device comprising an activated cold cathode
US3403282A (en) * 1964-12-02 1968-09-24 Siemens Ag Dispenser type cathode
US3405303A (en) * 1964-12-29 1968-10-08 Sylvania Electric Prod Arc discharge tube having an electrode which contains a light-emitting metal
US3706115A (en) * 1971-02-09 1972-12-19 Robert F Bleile Staple for sod and erosion control mattings
US4243624A (en) * 1979-05-21 1981-01-06 Exxon Research & Engineering Co. Method of making cathodes derived from ammonium-metal-chalcogen compounds

Also Published As

Publication number Publication date
FR979177A (fr) 1951-04-23
BE486753A (ja)
GB685444A (en) 1953-01-07

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