US2639399A - Electron emitter - Google Patents

Electron emitter Download PDF

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Publication number
US2639399A
US2639399A US153212A US15321250A US2639399A US 2639399 A US2639399 A US 2639399A US 153212 A US153212 A US 153212A US 15321250 A US15321250 A US 15321250A US 2639399 A US2639399 A US 2639399A
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US
United States
Prior art keywords
borides
emitters
boride
cathode
electron emitter
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
US153212A
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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 BE502232D priority Critical patent/BE502232A/xx
Priority to NL80503D priority patent/NL80503C/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US153212A priority patent/US2639399A/en
Priority to US178201A priority patent/US2659685A/en
Priority to GB5910/51A priority patent/GB678258A/en
Priority to DEI3955A priority patent/DE856666C/de
Priority to CH301197D priority patent/CH301197A/de
Priority to GB17063/51A priority patent/GB683940A/en
Application granted granted Critical
Publication of US2639399A publication Critical patent/US2639399A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00Details 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
    • H01J1/02Main electrodes
    • H01J1/13Solid thermionic cathodes
    • H01J1/14Solid thermionic cathodes characterised by the material
    • H01J1/148Solid thermionic cathodes characterised by the material with compounds having metallic conductive properties, e.g. lanthanum boride, as an emissive material
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25CPROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C25C7/02Electrodes; Connections thereof
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00Gas-filled discharge tubes with solid cathode
    • H01J17/02Details
    • H01J17/04Electrodes; Screens
    • H01J17/06Cathodes
    • H01J17/066Cold cathodes
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00Discharge tubes and lamps
    • H01J2893/0064Tubes with cold main electrodes (including cold cathodes)
    • H01J2893/0065Electrode systems
    • H01J2893/0066Construction, material, support, protection and temperature regulation of electrodes; Electrode cups

Definitions

  • My invention relates to improved electron emitters and particularly to metallic boride emitters.
  • the rare earth metals form borides of the general formula MeBe where Me is any metal of the rare earth group and that these borides form the essential ingredient of emitters having superior'properties:
  • Certain of the alkaline earth metals, such as barium, calcium and strontium also form borides of this general formula and possess the desirable properties of the rare earth metal borides, although to .a lesser degree.
  • Thorium borides of theformula THIB4 and THBG and the uranium borides UB4+UB2 (a mixture of borides) also possess desirable characteristics as the emitters.
  • borides of lanthanum, cerium, and'neodymium have been used separately and work very satisfactorily. Since many of the rare earth metals, however, are not available individually and it is a matter of considerable commercial importance that mischmetal (which is a natural mixture of the rare earth metals) provides a. very satisfactory metal boride emitter. It has also been found that a mixture of borides including one selected from the rare earth borides and one selected from the group consisting of the borides of barium, strontium, and calcium, particularly barium, is particularly advantageous.
  • the borides mentioned above are chemically and electrically stable, have high melting points, are generally metallic in character, and, therefore, have relatively good electrical conductivity.
  • electron emitters consisting essentially of these borides may be used in 'demountable systems which are frequently let down to the atmosphere without deterioration of the cathode material and no special care is're quired in storing.
  • They are generallychemically stable so that they are not adversely affected by moisture, oxygen or even hydrochloric acid. They also have the desirable property that no activation is required. to obtain emission and emission is uniform over the entire surface and remains substantially constant with time.
  • any contamination of other electrodes by deposition of the film of the evaporated material does not charge-up and as a result'cause sparking between the parts of the tube in which they are employed. thus rendering cathodes of these materials suitable for high voltage applications.
  • These materials also are refractory and have a low vapor pressure at relatively high operating temperatures. This quality, together with the relatively good electrical conductivity which permits thick coatings to be applied, provides emitters having very long life. As will be discussed in further detail, the materials'also emit currents of relatively high density and may be operated at high temperatures.
  • -Oathodes employing these materials are also capable of either direct or indirect heating and may be easily fabricated since they may be applied as a spray or by dipping or painting. They may also be pressed and sintered to providea solid emitter of the boride material.
  • Fig. 1 illustrates the characteristics of a number of emitters embodying the present invention
  • Fig. 2 illustrates a cathode embodying the invention
  • Fig. 3 is an enlarged partial elevational view in section of the cathode of Fig. 2
  • Figs. 4, 5 and 6 illustrate modified cathode constructions als'oembodying the present invention.
  • Fig. l of the drawing in which the logarithm to the base In of the ratio of current to absolute temperature squared is plotted as ordinates and the ratio of 1000 to absolute temperatureis plotted as abscissae.
  • the value of .7 for corresponds to an absolute temperature of 1428.5 degrees Kelvin.
  • fiheborides are relatively easy to produce and may to, :adizantagerbe .formed by reacting the metal with amorphous boron, pcwder by :heating in [vacuum 1G1. in an atmosphere .of: hydrogen or inert. gas.
  • the amorphous heron p wder-and the inetaltpowder or metal filmes arc m xed t ether and tweed prior t the heating. I-he l 1t of this operation is.
  • a eintered ma swh c ma be pul ze in abal ⁇ m an thenmadeintc a spray 0-1.
  • paste av-mixing w h a su t b bind r-or carrier su h mr ace a e .01"
  • the boride rod 7 is arranged to be directly heated by passage of current through the rod.
  • the rod is supported by leadin conductors l3 and M which surround the end of the rod 1 and over which a suitable conductive coating I5 is applied to improve the contact between the lead-in conductors and the rod.
  • a cathode applied to a planar electrode type of ,deyice -in which the electrodes are shown as an anode $6, a screen grid H, a control grid l8, a cathode l9, and a heater element 20.
  • the cathode is in the form of a disk haying. a rim 2i defining an open end recess on the side of the cathode facing the anode. Ellis reeegg is filled .with a body of boride materlal :22 w may be prepared by starting with the boride. powder and a suitable carrier and and filllll 'illlllg as previously described.
  • the-cathode may be heated by radiation from the heater element 29 and in addition by electron rdm nt by keecine the he 1 re en 0 t e nct ntia o 0d e the ⁇ mesa-ic d cended t i a par-v nttha he lac-r d mit en c t e P ent i ve ti ema wbe ed: 1 1 a 0, a mb at t r i he essentia c mme t f lin s?

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Solid Thermionic Cathode (AREA)
US153212A 1950-03-31 1950-03-31 Electron emitter Expired - Lifetime US2639399A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
BE502232D BE502232A (ja) 1950-03-31
NL80503D NL80503C (ja) 1950-03-31
US153212A US2639399A (en) 1950-03-31 1950-03-31 Electron emitter
US178201A US2659685A (en) 1950-03-31 1950-08-08 Boride cathodes
GB5910/51A GB678258A (en) 1950-03-31 1951-03-12 Improvements in and relating to electron emitters
DEI3955A DE856666C (de) 1950-03-31 1951-03-30 Thermionischer Elektronenspender
CH301197D CH301197A (de) 1950-03-31 1951-03-31 Kathode.
GB17063/51A GB683940A (en) 1950-03-31 1951-07-18 Improvements in and relating to cathodes for electric discharge apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US153212A US2639399A (en) 1950-03-31 1950-03-31 Electron emitter

Publications (1)

Publication Number Publication Date
US2639399A true US2639399A (en) 1953-05-19

Family

ID=22546234

Family Applications (1)

Application Number Title Priority Date Filing Date
US153212A Expired - Lifetime US2639399A (en) 1950-03-31 1950-03-31 Electron emitter

Country Status (6)

Country Link
US (1) US2639399A (ja)
BE (1) BE502232A (ja)
CH (1) CH301197A (ja)
DE (1) DE856666C (ja)
GB (2) GB678258A (ja)
NL (1) NL80503C (ja)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2744073A (en) * 1952-11-22 1956-05-01 Battelle Development Corp Thermionic emitter materials
US3312856A (en) * 1963-03-26 1967-04-04 Gen Electric Rhenium supported metallic boride cathode emitters
US3440475A (en) * 1967-04-11 1969-04-22 Lokomotivbau Elektrotech Lanthanum hexaboride cathode system for an electron beam generator
US3505553A (en) * 1966-05-12 1970-04-07 Philips Corp Radio-interference-free low-pressure mercury-vapor lamp
US3944866A (en) * 1974-04-08 1976-03-16 Canadian Patents & Development Ltd. Thermionic emitter of lanthanum strontium vanadates
US4249105A (en) * 1977-10-03 1981-02-03 Nippon Hoso Kyokai Gas-discharge display panel
US4260525A (en) * 1978-11-27 1981-04-07 Rca Corporation Single-crystal hexaborides and method of preparation
US6025038A (en) * 1998-08-26 2000-02-15 Board Of Regents Of The University Of Nebraska Method for depositing rare-earth boride onto a substrate
US6077617A (en) * 1998-08-26 2000-06-20 Board Of Regents Of The University Of Nebraska Rare-earth boride thin film system
US20100028235A1 (en) * 2006-02-06 2010-02-04 Lu-Chang Qin Synthesis and Processing of Rare-Earth Boride Nanowires as Electron Emitters
DE102011013262A1 (de) 2011-03-07 2012-09-13 Adlantis Dortmund Gmbh Ionisationsquelle und Nachweisgerät für Spurengase

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE971413C (de) * 1953-10-02 1959-01-22 Siemens Ag Vorrichtung zum tiegellosen Zonenschmelzen
FR2445605A1 (fr) * 1978-12-27 1980-07-25 Thomson Csf Cathode a chauffage direct et tube electronique haute frequence comportant une telle cathode
DE4305558A1 (de) * 1993-02-24 1994-08-25 Asea Brown Boveri Verfahren zur Herstellung von Drähten, welche insbesondere für Kathoden von Elektronenröhren geeignet sind

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1023485A (en) * 1908-11-20 1912-04-16 Orlando M Thowless Illuminant for electrical incandescent lamps.
US2117636A (en) * 1934-03-24 1938-05-17 Gerald B Tjoflat Thermionic electrode
US2501089A (en) * 1945-11-29 1950-03-21 Martin A Pomerantz Thermionic electron emitter
US2502331A (en) * 1948-12-21 1950-03-28 Rca Corp Geiger-muller counter for radioactive emission

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1023485A (en) * 1908-11-20 1912-04-16 Orlando M Thowless Illuminant for electrical incandescent lamps.
US2117636A (en) * 1934-03-24 1938-05-17 Gerald B Tjoflat Thermionic electrode
US2501089A (en) * 1945-11-29 1950-03-21 Martin A Pomerantz Thermionic electron emitter
US2502331A (en) * 1948-12-21 1950-03-28 Rca Corp Geiger-muller counter for radioactive emission

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2744073A (en) * 1952-11-22 1956-05-01 Battelle Development Corp Thermionic emitter materials
US3312856A (en) * 1963-03-26 1967-04-04 Gen Electric Rhenium supported metallic boride cathode emitters
US3505553A (en) * 1966-05-12 1970-04-07 Philips Corp Radio-interference-free low-pressure mercury-vapor lamp
US3440475A (en) * 1967-04-11 1969-04-22 Lokomotivbau Elektrotech Lanthanum hexaboride cathode system for an electron beam generator
US3944866A (en) * 1974-04-08 1976-03-16 Canadian Patents & Development Ltd. Thermionic emitter of lanthanum strontium vanadates
US4249105A (en) * 1977-10-03 1981-02-03 Nippon Hoso Kyokai Gas-discharge display panel
US4260525A (en) * 1978-11-27 1981-04-07 Rca Corporation Single-crystal hexaborides and method of preparation
US6025038A (en) * 1998-08-26 2000-02-15 Board Of Regents Of The University Of Nebraska Method for depositing rare-earth boride onto a substrate
US6077617A (en) * 1998-08-26 2000-06-20 Board Of Regents Of The University Of Nebraska Rare-earth boride thin film system
US20100028235A1 (en) * 2006-02-06 2010-02-04 Lu-Chang Qin Synthesis and Processing of Rare-Earth Boride Nanowires as Electron Emitters
US8501136B2 (en) 2006-02-06 2013-08-06 The University Of North Carolina At Chapel Hill Synthesis and processing of rare-earth boride nanowires as electron emitters
DE102011013262A1 (de) 2011-03-07 2012-09-13 Adlantis Dortmund Gmbh Ionisationsquelle und Nachweisgerät für Spurengase

Also Published As

Publication number Publication date
NL80503C (ja)
BE502232A (ja)
GB683940A (en) 1952-12-10
GB678258A (en) 1952-08-27
DE856666C (de) 1952-11-24
CH301197A (de) 1954-08-31

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