US2123024A - Electrode for electric discharge devices - Google Patents

Electrode for electric discharge devices Download PDF

Info

Publication number
US2123024A
US2123024A US82452A US8245236A US2123024A US 2123024 A US2123024 A US 2123024A US 82452 A US82452 A US 82452A US 8245236 A US8245236 A US 8245236A US 2123024 A US2123024 A US 2123024A
Authority
US
United States
Prior art keywords
electrode
metal
tube
oxide
layer
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
US82452A
Inventor
Emanuel R Piore
Malter Louis
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.)
RCA Corp
Original Assignee
RCA Corp
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 RCA Corp filed Critical RCA Corp
Priority to US82452A priority Critical patent/US2123024A/en
Priority to DER99485D priority patent/DE750419C/en
Priority to GB14997/37A priority patent/GB496556A/en
Application granted granted Critical
Publication of US2123024A publication Critical patent/US2123024A/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
    • H01J1/32—Secondary-electron-emitting electrodes

Definitions

  • This invention relates to electric discharge devices, particularly to electrodes therefor, and has for its principal object the provision of an electrode having improved photo-sensitive and secg ondary-electron emissive characteristics.
  • Fig. 1 is a diagrammatic view of an electron multlplierf system wherein an electrode constructed in accordance with the invention may proposed to oxidize the metal and to treat the l oxidized surface with caesium, rubidium, sodium, or other electro-positive metal.
  • a secondaryelectron emissive constant of 'l to 9 is obtainable f" with caesium on oxidized-silver: rubidium on oxidized silver will provide an emissive ratio of substantially 6.5 to 8.5 secondary electrons to each impinging electron.
  • the preferred practice is to mount the clean metal electrode structure in the tube and. after evacuation, to introduce oxygen into the.y tube.
  • the oxygen is activated orionized, as by the application of an externally applied high frequency neld and, thus activated. combines readily with the electrode metal.
  • the tube is re-,evacuated- Caesium, which may be contained Lin the form of pellets within an auxiliary container connecting with the tube contai the electrodes. isvaporized as by the applicationo heat and the resultingvaporenters'into the main tube and combineswith the A oxidized metal to render it emissive. ExcessiveJ caesium isremoved or "taken-up," within the tube.
  • the tube is baked, on the pump; and the l sealing-in operation completed.
  • 'I'he4 present invention contemplates and its practice provides a metal electrode which has not only been oxidized'and treated (as with caesium) I. but also re-oxidised and retreated witlr the same nalkali metal.
  • the metal whose surface is to be rendered emissive is selected from the group of metals whose oxides have a ⁇ heat of formation',1
  • the present invention involves a double application of caesii'im,y or the like (with the introduction of oxygen between these applications), to a metal whose oxide has a heat of formation of the same 10 order o f magnitude as that 0f caesium.
  • the metals whose emissive characteristics .may be enhanced by the improved method of my invention are beryllium, zirconium, molybdenum. columbium and zinc.
  • the heat of forl5 mation of the oxides, per oxygen bond, of these metals is of the order of 80,000 to 90,000 calories per mol.
  • the alkali metals preferably employed in treating the ⁇ above mentioned metals are cae-v sium, rubidium, and zpotassium.
  • the heat of '20 formation of the oxides of these metals are, respectively, 88,000, 88,500, and 86,800.
  • Sodium whose oxide has a heat of formation of substantially-100,000 may be included in this group.
  • the elec- 25 trode to be treated is first pre-oxidized, either electrolytlcally before it is mounted in the discharge tube, or by an oxygen glow discharge within the tube itself, or it may be oxidized within or without the tube in any known manner.
  • this oxide coating is of a thickness of they order of, say. three hundred atomic layers. 'With the oxidized electrode surface or surfaces mounted within the tube, the tube is highly evacuated and a substantiaiamount of caes'ium, or like al- 35 kali metal, is distilled into it. preferably in the manner previously described.
  • the excess ⁇ cae-- slum or other vapor is removed as by baking at 'a temperature of 200 P. for about ten minutes with the tube o'n the pump. admitted and allowed to remain in the tube for. say three minutes, until it has reacted with the caesium to form a layer of a mixture constituted of an oxide of caesium 'and the oxide o! the metal of which the base is formed..
  • the tube is then reexhausted, after which the electrode is again bathed in the alkali metal vapor. This' second bath o! metal vapor forms a molecular layer of thealkali metal on the siirface of the "mixed oxide layer".
  • the excess metal vapor isremoved i0 by baking and pumping, as before, and thetube is then sealed oil.
  • the device comprises a Y-shape evacuated container I, within which, adjacent the closed ends of one of its arms, is mounted a photosensitive cathode 3 and adjacent theclosed end of the other of its arms is an output electrode 5.
  • a third electrode 1 is mounted between ⁇ the input and output electrodes 3 and 5 in the angle or stem of the Y-shape container l.
  • Both electrodes 3 and I are constituted in accordance with the invention of a metal base having a mixed oxide coating and a layer of alkali metal superimposed on this coating.
  • the output electrode 5 may be of nickel or other suitable material.
  • a variable or a constant lightsource may be so disposed with respect to the container that light therefrom falls upon the photosensitive cathode.
  • such light source is exemplered by a lamp 8 connected'in circuit with a battery 9 and a variable rheostat II, and a lens I3.
  • an electromagnetic coil I5 may be disposed around one arm of the container between the photo-,sensitive cathode and the multi- A similar coil I 'I imay be disposed around the other ,arm of the container for the purpose of focusing secondary electrons upon the output electrode.
  • the several focusing coils may beprovided with unidirectional potential from a battery I9 or the like.
  • these coils are exemplified as being connected in parallel to the battery, ⁇ a potential divider 2
  • A1ternative1y, ⁇ . ⁇ electrostatic focusing o'f the electrons may be resorted to, or a combination of electrostatic and magnetic focusing.
  • the output electrode 5 may be connected to any suitable utilization circuit, such as a relay21.
  • the photosensitive-cathode may be connected tothe negative terminal of a potential divider 29 that connected across a source of unidirectional potential 3l, the output electrode 5 connected to the positive terminal of the potential divider and thev multiplying electrode 'I connected to an intermediate point thereon.
  • the relative .potentials shown in rthe drawing are to be construed solely as illustrative.
  • the base lupon which the mixed oxide layer and the alkali metal coating is applied may be it mere sheetvof beryllium intimately iointed, as by evaporation, to a base of another and cheaper metal, such for instance as nickel.
  • a base of another and cheaper metal such for instance as nickel.
  • Such construction is recommendedl where the metal to which the mixed oxide layer and alkali metal ⁇ coating is applied is not available in sheet form.
  • An electrode comprising a metal base having thereon a layer of a mixture of an oxide of said metal and an oxide of an alkali metal whose oxide has a heat of formation, per oxygen bond, of substantially the same order as that of the oxide of the metal constituting said base, and a coating of said alkali metal superimposed on said layer.
  • An electrode comprising a base of a metal whose oxide has a heat of formation, per oxygen bond, of the order of substantially 80,000 to 90,000
  • a layer on said base constituted of an' oxide of said metal and an oxide of an alkali metal Whose oxide has a heat of formation, per oxygen bond, of the order of substantially 80,000 to 100,000 calories per mol., and a surface coating of said alkali metal on said layer.
  • An electrode comprising a base of beryllium, a layer on said base constituted of beryllium and casesium oxides and a surface coating of caesium on said layer.
  • An electrode comprising a base of beryllium, a layer on said base constituted of beryllium and rubidium oxides and a surface coating of rubidium on said layer.
  • An electrode comprising a base of beryllium

Description

July 5, 193s.
E. R. PloRE Er AL 2,123,024 ELECTRODE FOR ELECTRIC DISCHARGE ,DEEVIGEISk Filed May 29, 193s t Louis Malter M Gttorneg nieuwe .my s, yuns f UNITED STATES anaest- PA'rENT-v OFFICE' ELECTRODE FOB EDECTRIC DISCHARGE DEVICES 1 Emanuel lt. Piore, Philadelp Pa.. and Louis )Kalten Oaklyn, N. J., asaignors to Radio Cor. poration of America. a corporation of Delaware Application May zo, massaal No. n.452 schaun.- wieso-#215) This invention relates to electric discharge devices, particularly to electrodes therefor, and has for its principal object the provision of an electrode having improved photo-sensitive and secg ondary-electron emissive characteristics.
Other objects will be apparent and the invention itself will be best understood by reference to the'foliowing specification andto lthe accompanying drawing, wherein:
1o Fig. 1 is a diagrammatic view of an electron multlplierf system wherein an electrode constructed in accordance with the invention may proposed to oxidize the metal and to treat the l oxidized surface with caesium, rubidium, sodium, or other electro-positive metal. A secondaryelectron emissive constant of 'l to 9 is obtainable f" with caesium on oxidized-silver: rubidium on oxidized silver will provide an emissive ratio of substantially 6.5 to 8.5 secondary electrons to each impinging electron.
In constructing electrodes of the type described, the preferred practice is to mount the clean metal electrode structure in the tube and. after evacuation, to introduce oxygen into the.y tube. The oxygen is activated orionized, as by the application of an externally applied high frequency neld and, thus activated. combines readily with the electrode metal. When oxidization has been completed the tube is re-,evacuated- Caesium, which may be contained Lin the form of pellets within an auxiliary container connecting with the tube contai the electrodes. isvaporized as by the applicationo heat and the resultingvaporenters'into the main tube and combineswith the A oxidized metal to render it emissive. ExcessiveJ caesium isremoved or "taken-up," within the tube. The tube is baked, on the pump; and the l sealing-in operation completed.
'I'he4 present invention contemplates and its practice provides a metal electrode which has not only been oxidized'and treated (as with caesium) I. but also re-oxidised and retreated witlr the same nalkali metal. The metal whose surface is to be rendered emissive is selected from the group of metals whose oxides have a `heat of formation',1
per oxygen bond, of .the 'same'or substantially Il the same order as that of the metallic element with which it is treated. Thus, whereas the prior art dictates the treatment of silver (whose oxide has a -heat of 4formation of the order of 5000 calories per mol.) with a single application of caesium (whose oxide hasla heat of formation l,
- of substantially 88,000 calories per mol.) the present invention involves a double application of caesii'im,y or the like (with the introduction of oxygen between these applications), to a metal whose oxide has a heat of formation of the same 10 order o f magnitude as that 0f caesium.
Among the metals whose emissive characteristics .may be enhanced by the improved method of my invention are beryllium, zirconium, molybdenum. columbium and zinc. The heat of forl5 mation of the oxides, per oxygen bond, of these metals is of the order of 80,000 to 90,000 calories per mol. The alkali metals preferably employed in treating the `above mentioned metals are cae-v sium, rubidium, and zpotassium. The heat of '20 formation of the oxides of these metals are, respectively, 88,000, 88,500, and 86,800. Sodium whose oxide has a heat of formation of substantially-100,000 may be included in this group.
yI n carrying the invention intoeil'ect the elec- 25 trode to be treated is first pre-oxidized, either electrolytlcally before it is mounted in the discharge tube, or by an oxygen glow discharge within the tube itself, or it may be oxidized within or without the tube in any known manner. Pref- '3o erably this oxide coating is of a thickness of they order of, say. three hundred atomic layers. 'With the oxidized electrode surface or surfaces mounted within the tube, the tube is highly evacuated and a substantiaiamount of caes'ium, or like al- 35 kali metal, is distilled into it. preferably in the manner previously described. The excess `cae-- slum or other vapor is removed as by baking at 'a temperature of 200 P. for about ten minutes with the tube o'n the pump. admitted and allowed to remain in the tube for. say three minutes, until it has reacted with the caesium to form a layer of a mixture constituted of an oxide of caesium 'and the oxide o! the metal of which the base is formed.. The tubeis then reexhausted, after which the electrode is again bathed in the alkali metal vapor. This' second bath o! metal vapor forms a molecular layer of thealkali metal on the siirface of the "mixed oxide layer". The excess metal vapor isremoved i0 by baking and pumping, as before, and thetube is then sealed oil. I
f Referring now to Fig. l of the drawing inwhich electrodes'formed in accordance with the invention are utilised in an electron multiplier plying electrode.
`cathode in random directions.
device of a' known type. The device comprises a Y-shape evacuated container I, within which, adjacent the closed ends of one of its arms, is mounted a photosensitive cathode 3 and adjacent theclosed end of the other of its arms is an output electrode 5. A third electrode 1 is mounted between `the input and output electrodes 3 and 5 in the angle or stem of the Y-shape container l. Both electrodes 3 and I are constituted in accordance with the invention of a metal base having a mixed oxide coating and a layer of alkali metal superimposed on this coating. The output electrode 5 may be of nickel or other suitable material.
A variable or a constant lightsource may be so disposed with respect to the container that light therefrom falls upon the photosensitive cathode. In the drawing, such light source is exempliiled by a lamp 8 connected'in circuit with a battery 9 and a variable rheostat II, and a lens I3.
Under the influence of light from the source, electrons leave the surface of the photosensitive Since it isdesirable to focus all suchelectrons upon the multl, plying electrode an electromagnetic coil I5 may be disposed around one arm of the container between the photo-,sensitive cathode and the multi- A similar coil I 'I imay be disposed around the other ,arm of the container for the purpose of focusing secondary electrons upon the output electrode.
The several focusing coils may beprovided with unidirectional potential from a battery I9 or the like. In the drawing these coils are exemplified as being connected in parallel to the battery,\ a potential divider 2| and a plurality of contact' devices 23 and 25 being'utilized for the purpose of individually controlling the magnitude of the several focusing field currents. It is our understanding that the polarity of the coils is immaterial. A1ternative1y,`.` electrostatic focusing o'f the electrons may be resorted to, or a combination of electrostatic and magnetic focusing.
In the operation of an electron multiplier of thetype under discussion the output electrode 5 may be connected to any suitable utilization circuit, such as a relay21. When utilizing a multiplier of the type shown, the photosensitive-cathode may be connected tothe negative terminal of a potential divider 29 that connected across a source of unidirectional potential 3l, the output electrode 5 connected to the positive terminal of the potential divider and thev multiplying electrode 'I connected to an intermediate point thereon. The relative .potentials shown in rthe drawing are to be construed solely as illustrative.
f siumvon said layer.
Referring to Fig. 2, the base lupon which the mixed oxide layer and the alkali metal coating is applied may be it mere sheetvof beryllium intimately iointed, as by evaporation, to a base of another and cheaper metal, such for instance as nickel. Such construction is recommendedl where the metal to which the mixed oxide layer and alkali metal `coating is applied is not available in sheet form.
As indicated in both Figs. 1 and 2, when the electrons constituting the primary beam from the cathode strike the composite electrode surface with sufficient energy, secondary-electrons are emitted. The electrons, so released are drawn to the collector electrode, or if desired to another similar surface for further multiplication by reason of the electric field applied between the emitter and the target electrode.
While the invention has been described in connection with a photo-actuated electron-multiplier tube, it is to be understood that its application is not to be limited tothe particular type of tube here described, as the disclosure, in this respect, is merely illustrative for purposes of explaining the inventive concept.
What is claimed is:
1: An electrode comprising a metal base having thereon a layer of a mixture of an oxide of said metal and an oxide of an alkali metal whose oxide has a heat of formation, per oxygen bond, of substantially the same order as that of the oxide of the metal constituting said base, and a coating of said alkali metal superimposed on said layer.
2. An electrode comprising a base of a metal whose oxide has a heat of formation, per oxygen bond, of the order of substantially 80,000 to 90,000
calories per mol., a layer on said base constituted of an' oxide of said metal and an oxide of an alkali metal Whose oxide has a heat of formation, per oxygen bond, of the order of substantially 80,000 to 100,000 calories per mol., and a surface coating of said alkali metal on said layer.
3. An electrode comprising a base of beryllium, a layer on said base constituted of beryllium and casesium oxides and a surface coating of caesium on said layer.
4. An electrode comprising a base of beryllium, a layer on said base constituted of beryllium and rubidium oxides and a surface coating of rubidium on said layer.
5. An electrode comprising a base of beryllium,
a layer on said base constituted of beryllium `and f potassium oxides and asurface coating of potas- EMANUEL' R. PIORE. LOUIS MALTER.
US82452A 1936-05-29 1936-05-29 Electrode for electric discharge devices Expired - Lifetime US2123024A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US82452A US2123024A (en) 1936-05-29 1936-05-29 Electrode for electric discharge devices
DER99485D DE750419C (en) 1936-05-29 1937-05-29 Process for the production of secondary emission-capable layers on impact electrodes
GB14997/37A GB496556A (en) 1936-05-29 1937-05-31 Improvements in electrodes for electron discharge devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US82452A US2123024A (en) 1936-05-29 1936-05-29 Electrode for electric discharge devices

Publications (1)

Publication Number Publication Date
US2123024A true US2123024A (en) 1938-07-05

Family

ID=22171310

Family Applications (1)

Application Number Title Priority Date Filing Date
US82452A Expired - Lifetime US2123024A (en) 1936-05-29 1936-05-29 Electrode for electric discharge devices

Country Status (3)

Country Link
US (1) US2123024A (en)
DE (1) DE750419C (en)
GB (1) GB496556A (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2428289A (en) * 1942-11-07 1947-09-30 Charles Schiffman Electron tube coating
US2443324A (en) * 1942-11-07 1948-06-15 Charles Schiffman Electronic tube
US2453810A (en) * 1945-05-02 1948-11-16 Smith Insdustries Photoelectric tube
US2472189A (en) * 1941-07-03 1949-06-07 Hartford Nat Bank & Trust Co Thermionic tube having a secondary-emission electrode
US2639963A (en) * 1948-04-05 1953-05-26 Sylvania Electric Prod Secondary emitter and method of manufacture
US2682479A (en) * 1949-03-03 1954-06-29 Rca Corp Photosurface of a panchromatic type and method of preparing same
US2708726A (en) * 1948-12-04 1955-05-17 Emi Ltd Electron discharge device employing secondary electron emission and method of making same
US4639638A (en) * 1985-01-28 1987-01-27 Sangamo Weston, Inc. Photomultiplier dynode coating materials and process

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT101557B (en) * 1923-04-11 1925-11-10 Philips Nv Discharge tube.
NL38911C (en) * 1929-08-28
AT131785B (en) * 1930-09-30 1933-02-10 Philips Nv Photoelectric cell.
GB421256A (en) * 1933-03-14 1934-12-07 Max Albin Ernst Pressler Improvements in processes for producing photo-electric cells
AT143970B (en) * 1934-03-26 1935-12-10 Philips Nv Method of making an electron emitting electrode.
FR787821A (en) * 1934-03-26 1935-09-30 Philips Nv Method of manufacturing electron-emitting electrodes

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2472189A (en) * 1941-07-03 1949-06-07 Hartford Nat Bank & Trust Co Thermionic tube having a secondary-emission electrode
US2428289A (en) * 1942-11-07 1947-09-30 Charles Schiffman Electron tube coating
US2443324A (en) * 1942-11-07 1948-06-15 Charles Schiffman Electronic tube
US2453810A (en) * 1945-05-02 1948-11-16 Smith Insdustries Photoelectric tube
US2639963A (en) * 1948-04-05 1953-05-26 Sylvania Electric Prod Secondary emitter and method of manufacture
US2708726A (en) * 1948-12-04 1955-05-17 Emi Ltd Electron discharge device employing secondary electron emission and method of making same
US2682479A (en) * 1949-03-03 1954-06-29 Rca Corp Photosurface of a panchromatic type and method of preparing same
US4639638A (en) * 1985-01-28 1987-01-27 Sangamo Weston, Inc. Photomultiplier dynode coating materials and process

Also Published As

Publication number Publication date
DE750419C (en) 1944-12-21
GB496556A (en) 1938-11-30

Similar Documents

Publication Publication Date Title
US2842706A (en) Cold cathode vacuum tube
US2292151A (en) Electric discharge device
US2233786A (en) Fluorescent screen assembly and method of manufacture
US2850666A (en) Helix structure for traveling-wave tubes
US2898499A (en) Transmission secondary emission dynode structure
US2123024A (en) Electrode for electric discharge devices
US3197662A (en) Transmissive spongy secondary emitter
US3114044A (en) Electron multiplier isolating electrode structure
US3739216A (en) Secondary electron multipliers with single layer cermet coatings
US2401734A (en) Photoelectric electron multiplier
US2073599A (en) Electric discharge device
US2620287A (en) Secondary-electron-emitting surface
US3989971A (en) Gateable electron image intensifier
US3128406A (en) Radiation image pickup tube
US2147669A (en) Secondary electron emitting electrode
US2162391A (en) Electron tube with high ohmic wall coatings
US2178238A (en) Electric discharge device
US2752519A (en) Method and apparatus for use in chemical evaporation processes
US2316276A (en) Electron discharge apparatus
US3350594A (en) Image intensifier having continuous conducting layer between porous metallic coating and luminescent layer
US2171213A (en) Television transmitting tube and electrode structure
US2526574A (en) Secondary emitter
US2873218A (en) Method of making an electron emitter
US2256460A (en) Electron discharge device
US2879406A (en) Electron discharge tube structure