US2737607A - Incandescible cathode - Google Patents

Incandescible cathode Download PDF

Info

Publication number
US2737607A
US2737607A US297306A US29730652A US2737607A US 2737607 A US2737607 A US 2737607A US 297306 A US297306 A US 297306A US 29730652 A US29730652 A US 29730652A US 2737607 A US2737607 A US 2737607A
Authority
US
United States
Prior art keywords
alkaline earth
cavity
cathode
emissive surface
electron
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
US297306A
Other languages
English (en)
Inventor
Lemmens Hendrikus Johannes
Jansen Marinus Jacobus
Haayman Pieter Willem
Linden Petrus Cornelis Van Der
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.)
Hartford National Bank and Trust Co
Original Assignee
Hartford National Bank and Trust 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
Application filed by Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
Application granted granted Critical
Publication of US2737607A publication Critical patent/US2737607A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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

  • This invention relates to an incandescible cathode and more particularly to a cathode containing a supply of an alkaline earth compound capable of reduction by a refractory metal to free alkaline earth metal.
  • Cathodes of the aforesaid type have been described in U. S. Patent 2,543,728 to H. I. Lemmens et al.
  • a reservoir of alkalineearth compounds is located within a cavity of a body of refractory material which body has a porous wall portion and is tightly'closed so that the pores of the porous wall portion form the largest connecting passageways connecting the reservoir of alkaline earth compounds with the outside of the cathode.
  • the alkaline earth compounds disclosed in the said patent are the carbonates of the alkaline earth metals, for example barium and strontium which decompose at elevated temperatures to form the oxides of the alkaline earth metals with release of carbon dioxide. The latter must then be pumped off continuously to maintain a high vacuum in the tube.
  • the cathode comprises a structure forming an internal cavity, the portion of the structure surrounding the cavity consisting of a refractory metal such as tungsten, molybdenum, tantalurn, zirconium or hafnium.
  • a refractory metal such as tungsten, molybdenum, tantalurn, zirconium or hafnium.
  • an alkaline earth boride for example, BaBs or SrBs, and mixtures of those compounds is disposed.
  • the cavity is sealed by means of a wall of porous refractory metal, the pores of this wall forming the largest passageways connecting the cavity to the exterior of the cathode.
  • the porous wall of the cavity preferably consists of a body of tungsten formed by pressing powdered tungsten and sintering the same at temperatures exceeding 1600n C. in order to obtain tungsten body of required porosity.
  • the borides do not require a high formation temperature such as carbonates the tungsten may be sintered as low as 1400 C. However, therein very line powder should be used.
  • the borides of the alkaline earth metals should be preferably in a crystalline state.
  • the cathode shown in the drawing comprises a porous tungsten plate 1 formed as described in U. S. Patent 2,543,728 in order to have the correct porosity.
  • the plate is 0.5 mm. thick and 3 mms. in diameter.
  • the tungsten plate 1 together with a cup-shaped molybdenum member 2 with a sharp upper edge 3 to which the tungsten plate is secured forms an internal cavity in which a supply 4 of about 1 to 5 mgs. of barium boride is disposed. Plate 1 is welded to the edge 3 to tightly seal the cavity.
  • the cathode is heated by means of a heater 5 disposed within a tubular extension 6 of the cup-shaped molybdenum member.
  • a dispenser cathode comprising a structure forming an internal cavity and having an electron emissive surface, a porous sintered body of refractory metal forming part of the wall of said structure, said structure being tightly closed with the pores of said wall portion constituting the largest passageways connecting the cavity to said electron emissive surface, and a supply within said cavity of an alkaline earth material capable of furnishing free alkaline earth metal to said electron-emissive surface at a rate sufficient to maintain a monomolecular layer of alkaline earth metal thereon, said material consisting essentially of an alkaline earth boride.
  • a dispenser cathode comprising a structure forming an internal cavity and having an electron emissive surface, a porous sintered body of tungsten forming part of the wall of said structure, said structure being tightly closed with the pores of said wall portion constituting the largest passageways connecting said cavity to said electronemissive surface, and a supply within said cavity of an alkaline earth material capable of furnishing free alkaline earth metal to said surface at a rate sutlicient to maintain a monomolecular layer of alkaline earth metal thereon, said material consisting essentially of an alkaline earth boride.

Landscapes

  • Electron Sources, Ion Sources (AREA)
  • Solid Thermionic Cathode (AREA)
US297306A 1951-07-17 1952-07-05 Incandescible cathode Expired - Lifetime US2737607A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL309313X 1951-07-17

Publications (1)

Publication Number Publication Date
US2737607A true US2737607A (en) 1956-03-06

Family

ID=19783575

Family Applications (1)

Application Number Title Priority Date Filing Date
US297306A Expired - Lifetime US2737607A (en) 1951-07-17 1952-07-05 Incandescible cathode

Country Status (5)

Country Link
US (1) US2737607A (en, 2012)
BE (1) BE512852A (en, 2012)
CH (1) CH309313A (en, 2012)
FR (1) FR1071683A (en, 2012)
GB (1) GB699287A (en, 2012)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2869017A (en) * 1956-10-24 1959-01-13 Philips Corp Thermionic dispenser cathode
US2928013A (en) * 1954-12-23 1960-03-08 Siemens Ag Electrical discharge device
US3079515A (en) * 1960-08-22 1963-02-26 Gen Electric Energy conversion device and methods of making
US3258636A (en) * 1961-09-01 1966-06-28 Electron emitter with activator of sill cide, boride or carbide of solid solu- tion of barium and at least one other alkaline earth metal
US3513349A (en) * 1966-01-08 1970-05-19 Matsushita Electronics Corp Discharge tube

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1720654A (en) * 1925-05-13 1929-07-09 Radio Patents Corp Photo-electric cell
US1936334A (en) * 1929-01-31 1933-11-21 Gen Scientific Corp Electrode
US2121589A (en) * 1934-06-28 1938-06-21 Westinghouse Electric & Mfg Co Emissive incandescent cathode
US2543728A (en) * 1947-11-26 1951-02-27 Hartford Nat Bank & Trust Co Incandescible cathode
US2647216A (en) * 1950-04-01 1953-07-28 Rca Corp Dispenser cathode

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1720654A (en) * 1925-05-13 1929-07-09 Radio Patents Corp Photo-electric cell
US1936334A (en) * 1929-01-31 1933-11-21 Gen Scientific Corp Electrode
US2121589A (en) * 1934-06-28 1938-06-21 Westinghouse Electric & Mfg Co Emissive incandescent cathode
US2543728A (en) * 1947-11-26 1951-02-27 Hartford Nat Bank & Trust Co Incandescible cathode
US2647216A (en) * 1950-04-01 1953-07-28 Rca Corp Dispenser cathode

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2928013A (en) * 1954-12-23 1960-03-08 Siemens Ag Electrical discharge device
US2869017A (en) * 1956-10-24 1959-01-13 Philips Corp Thermionic dispenser cathode
US3079515A (en) * 1960-08-22 1963-02-26 Gen Electric Energy conversion device and methods of making
US3258636A (en) * 1961-09-01 1966-06-28 Electron emitter with activator of sill cide, boride or carbide of solid solu- tion of barium and at least one other alkaline earth metal
US3513349A (en) * 1966-01-08 1970-05-19 Matsushita Electronics Corp Discharge tube

Also Published As

Publication number Publication date
FR1071683A (fr) 1954-09-03
GB699287A (en) 1953-11-04
CH309313A (de) 1955-08-31
BE512852A (en, 2012)

Similar Documents

Publication Publication Date Title
US2543728A (en) Incandescible cathode
US2912611A (en) Thermionic cathodes
US2121589A (en) Emissive incandescent cathode
US2700118A (en) Incandescible cathode
US2528547A (en) Hydrogen thyratron
US3373307A (en) Dispenser cathode
US2389060A (en) Refractory body of high electronic emission
US2173259A (en) Active metal compounds for vacuum tubes
US2716716A (en) Cathode containing a supply of an electron-emissive material
US2741717A (en) Dispenser type cathode having gettercoated parts
US4494035A (en) Thermoelectric cathode for a hyperfrequency valve and valves incorporating such cathodes
US2737607A (en) Incandescible cathode
US3159461A (en) Thermionic cathode
US3258636A (en) Electron emitter with activator of sill cide, boride or carbide of solid solu- tion of barium and at least one other alkaline earth metal
US3041209A (en) Method of making a thermionic cathode
GB713140A (en) Improvements in or relating to the manufacture of dispenser cathodes
US3358178A (en) Metal-porous body having pores filled with barium scandate
US2798182A (en) Dispenser cathode having heater embedded in densely sintered receptacle wall
US2848644A (en) Thermionic cathode
US2914402A (en) Method of making sintered cathodes
US3458749A (en) Dispenser cathode made of tungsten powder having a grain size of less than three microns
Beck High-current-density thermionic emitters: A survey
US3269804A (en) Dispenser cathode and method for the production thereof
KR920001334B1 (ko) 디스펜서 음극
US3201639A (en) Thermionic dispenser cathode