US3651360A - Triode electron gun with positive grid and modular cathode - Google Patents

Triode electron gun with positive grid and modular cathode Download PDF

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Publication number
US3651360A
US3651360A US818735A US3651360DA US3651360A US 3651360 A US3651360 A US 3651360A US 818735 A US818735 A US 818735A US 3651360D A US3651360D A US 3651360DA US 3651360 A US3651360 A US 3651360A
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United States
Prior art keywords
cathode
grid
extracting
anode
screen
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Expired - Lifetime
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US818735A
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English (en)
Inventor
Jean Sommeria
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Alcatel Heurtey SA
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Alcatel Heurtey SA
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    • 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
    • H01J3/029—Schematic arrangements for beam forming

Definitions

  • ABSTRACT An electron gun in which the space for electron extraction is physically separated from the space for electron acceleration.
  • a non-emissive screen grid is located on the cathode and a second grid is located in the electron shadow of the screen grid.
  • An anode is located beyond the second grid for accelerating the beam.
  • the present invention relates to improvements in electron guns, commonly known in the art as Pierce electron guns.
  • the electrons are generally pulled from an emitting cathode and accelerated towards an anode in one single operation.
  • extracting electrons from the cathode and accelerating them towards an anode are two quite distinct physical processes, so that superimposing of both processes makes it difficult to obtain a straight line propagation of the electrons.
  • the electrons flow from the cathode in all directions.
  • setting up a strong accelerating field between cathode and anode leads to the use of prohibitive potential differences.
  • An object of the present invention is to obtain a straight line, parallel beam of high energy electrons by using relatively small electrical fields.
  • the invention consists essentially of a gun where the space in which the physical process of electron extraction takes place is separated from the space in which the physical process of electron acceleration takes place, by placing each process in a separate electrically defined space, the two spaces being adjacent and having between them a well defined separation.
  • the invention includes the combination inside a triode electron gun, of a thermo-emissive cathode whose surface is made partially non-emissive by addition of a screen-grid; a grid positively biased in relation with the cathode, located near this cathode and of the same shape as that of the screengrid, and an anode biased positively in relation with the grid, the cathode, screen-grid and positively biased grid being preferably of shapes preventing the electrons emitted by the cathode from striking the biased grid.
  • such an improved gun includes a cathode heated by a filament or by electronic bombardment a first screen-grid coated on the cathode; and a second grid, located a short distance from the cathode and brought to a positive voltage in relation with the cathode, both grids being of identical structure and having thus the same number of identically shaped meshes.
  • the number of meshes is preferably small but their dimensions are relatively large.
  • the meshes of both grids have the same arrangement, so that they can overlap each other, and the first grid acts as a screen for preventing electrons from striking the second grid; the meshes being so shaped that the elementary electron beams drawn from the second grid pass through the meshes of the second grid without striking the solid portions thereof.
  • the first grid is in good mechanical contact with the cathode but in poor thermal contact with this latter, so that the first grid is at a lower temperature than the cathode and non-emissive.
  • FIG. 1 illustrates diagrammatically the gun
  • FIG. 2 shows a rational geometrical configuration of the grids.
  • the gun includes an emissive cathode 1 fitted on a metal cylindric tube 2 supported on a part 3 made of insulating material.
  • the tube 7 is fitted on the base 5 coaxial with the tube 2.
  • the filament 4 is supplied from an AC voltage source 8 and,
  • a honeycomb screen-grid 10 such as the one shown on FIG. 2, for example, is located on the cathode I. This rid consists of seven hexagonal meshes. As shown in FIG. screen grid 10 is mounted directly on cathode l with good mechanical contact therewith. The thin support spaces screen grid '10 from cathode l, thermally isolating the screen grid from the cathode.
  • This tube 12 is fitted on the part 3 through a tube 14 made of insulating material.
  • a grid 15 with the same shape as the screen grid 10 illustrated in FIG. 2, and located in such a manner that it is exactly opposed and coincident to the said screen grid, a few millimeters in front of this latter.
  • the grid 15 is brought to a voltage positive in relation with the cathode l voltage through a DC voltage source 16.
  • a circular anode l7 centered on the axis of the gun, is located a few centimeters from the grid 15 and is brought to a positive voltage in relation with the potential of this latter through a DC voltage source 18.
  • This anode 17 is, on the other side, connected to earth.
  • the electron gun of this structure works as follows
  • the cathode l is heated by an electron bombardment pulled from the filament 4 by the potential difference present between the cathode l and the filament 4.
  • the electrons are pulled from the cathode 1 by the grid 15 which is at a positive voltage in relation with the cathode.
  • FIG. 1 In FIG. 1 are shown three electron beams. These beams are, in fact, passing through three meshes of the grid 10 located on one diameter and the three corresponding meshes of the grid 15. The edges of the meshes of the grids l0 and 15 are so shaped that electrons are pulled from cathode and do not strike the solid parts of the meshes of the grid 15.
  • the shapes of the ring 11 and anode 17, as well as the voltages applied to these components, have been designed in order that the three electron beams illustrated on FIG. 1 join in one single cylindric beam parallel to the axis of the gun.
  • a high energy electron gun comprising a cathode, a thin mechanical, electrically-conductive support ring having one end fixed on the cathode and having a remote end extending outward from the cathode, a screen grid mounted on to the remote end of the thin support ring whereby the screen grid is in good mechanical contact with the cathode and poor thermal contact with the cathode, thereby thermally isolating the screen grid from the cathode, an extracting grid spaced from the cathode and defining therewith an electron extracting space, openings in the extracting grid aligned with openings in the screen grid, a first continuous power source having a negative terminal connected continuously to the cathode and hav ing a positive terminal connected to the extracting grid for continuously positively biasing the extracting grid with respect to the cathode, a ring anode having a central aperture for passing electrons spaced from the extracting grid, the extracting grid and the ring anode forming therebetween an accelerating space which is relatively
US818735A 1968-04-26 1969-04-23 Triode electron gun with positive grid and modular cathode Expired - Lifetime US3651360A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR149764 1968-04-26

Publications (1)

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US3651360A true US3651360A (en) 1972-03-21

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US818735A Expired - Lifetime US3651360A (en) 1968-04-26 1969-04-23 Triode electron gun with positive grid and modular cathode

Country Status (7)

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US (1) US3651360A (de)
BE (1) BE731965A (de)
DE (1) DE1919451B2 (de)
FR (1) FR1582070A (de)
GB (1) GB1234517A (de)
LU (1) LU58469A1 (de)
NL (1) NL6906459A (de)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2348617A1 (de) * 1972-09-28 1974-04-04 Varian Associates Elektronenstrahlerzeugersystem
US3818260A (en) * 1973-03-05 1974-06-18 Sperry Rand Corp Electron gun with masked cathode and non-intercepting control grid
US3852633A (en) * 1972-12-13 1974-12-03 Varian Associates Gridded electron gun
US3859552A (en) * 1972-03-02 1975-01-07 Siemens Ag Electron beam generator for transit-time electron discharge tubes
USB160045I5 (de) * 1971-07-06 1976-01-13
US4680500A (en) * 1986-03-06 1987-07-14 The United States Of America As Represented By The Secretary Of The Air Force Integral grid/cathode for vacuum tubes
US20030010934A1 (en) * 1999-10-07 2003-01-16 Victor Katsap Lens array for electron beam lithography tool
US20070145304A1 (en) * 2003-10-20 2007-06-28 La Calhene Electron gun with a focusing anode, forming a window for said gun and application thereof to irradiation and sterilization
US20100026161A1 (en) * 2006-10-23 2010-02-04 Ulvac, Inc Method of Controlling Electron Beam Focusing of Pierce-Type Electron Gun and Control Apparatus Therefor
US20110012495A1 (en) * 2009-07-20 2011-01-20 Advanced Electron Beams, Inc. Emitter Exit Window
FR3077922A1 (fr) * 2018-02-15 2019-08-16 Thales Grille circulaire pour une cathode cylindrique de tube hyperfrequence a faisceau lineaire, et procede de depose associe

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4593230A (en) * 1982-03-29 1986-06-03 Litton Systems, Inc. Dual-mode electron gun
GB9712243D0 (en) * 1997-06-13 1997-08-13 Eev Ltd Grids
GB0123451D0 (en) 2001-09-28 2001-11-21 Mitel Knowledge Corp Device for reducing structural-acoustical coupling between the diaphragm vibration field and the enclosure acoustic modes

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2398829A (en) * 1941-05-28 1946-04-23 Rca Corp Electron discharge device
US2758234A (en) * 1952-11-28 1956-08-07 Loewe Opta Ag Electrode system for cathode ray tubes
US3107313A (en) * 1959-10-30 1963-10-15 Johann R Hechtel Velocity modulated electron tube with cathode means providing plural electron streams
US3154711A (en) * 1961-06-19 1964-10-27 Gen Electric Electron beam focusing by means of contact differences of potential
US3558967A (en) * 1969-06-16 1971-01-26 Varian Associates Linear beam tube with plural cathode beamlets providing a convergent electron stream

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2398829A (en) * 1941-05-28 1946-04-23 Rca Corp Electron discharge device
US2758234A (en) * 1952-11-28 1956-08-07 Loewe Opta Ag Electrode system for cathode ray tubes
US3107313A (en) * 1959-10-30 1963-10-15 Johann R Hechtel Velocity modulated electron tube with cathode means providing plural electron streams
US3154711A (en) * 1961-06-19 1964-10-27 Gen Electric Electron beam focusing by means of contact differences of potential
US3558967A (en) * 1969-06-16 1971-01-26 Varian Associates Linear beam tube with plural cathode beamlets providing a convergent electron stream

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USB160045I5 (de) * 1971-07-06 1976-01-13
US3983446A (en) * 1971-07-06 1976-09-28 Varian Associates Gridded convergent flow electron gun for linear beam tubes
US3859552A (en) * 1972-03-02 1975-01-07 Siemens Ag Electron beam generator for transit-time electron discharge tubes
DE2348617A1 (de) * 1972-09-28 1974-04-04 Varian Associates Elektronenstrahlerzeugersystem
US3852633A (en) * 1972-12-13 1974-12-03 Varian Associates Gridded electron gun
US3818260A (en) * 1973-03-05 1974-06-18 Sperry Rand Corp Electron gun with masked cathode and non-intercepting control grid
US4680500A (en) * 1986-03-06 1987-07-14 The United States Of America As Represented By The Secretary Of The Air Force Integral grid/cathode for vacuum tubes
US7345290B2 (en) * 1999-10-07 2008-03-18 Agere Systems Inc Lens array for electron beam lithography tool
US20030010934A1 (en) * 1999-10-07 2003-01-16 Victor Katsap Lens array for electron beam lithography tool
US20070145304A1 (en) * 2003-10-20 2007-06-28 La Calhene Electron gun with a focusing anode, forming a window for said gun and application thereof to irradiation and sterilization
US7800012B2 (en) * 2003-10-20 2010-09-21 La Calhene Electron gun with a focusing anode, forming a window for said gun and application thereof to irradiation and sterilization
US20100026161A1 (en) * 2006-10-23 2010-02-04 Ulvac, Inc Method of Controlling Electron Beam Focusing of Pierce-Type Electron Gun and Control Apparatus Therefor
US8198797B2 (en) * 2006-10-23 2012-06-12 Ulvac, Inc. Method of controlling electron beam focusing of pierce-type electron gun and control apparatus therefor
TWI421898B (zh) * 2006-10-23 2014-01-01 Ulvac Inc 皮爾斯式電子槍之電子射束之聚焦之控制方法及控制裝置
US20110012495A1 (en) * 2009-07-20 2011-01-20 Advanced Electron Beams, Inc. Emitter Exit Window
US8339024B2 (en) 2009-07-20 2012-12-25 Hitachi Zosen Corporation Methods and apparatuses for reducing heat on an emitter exit window
FR3077922A1 (fr) * 2018-02-15 2019-08-16 Thales Grille circulaire pour une cathode cylindrique de tube hyperfrequence a faisceau lineaire, et procede de depose associe
WO2019158478A1 (fr) * 2018-02-15 2019-08-22 Thales Grille circulaire pour une cathode cylindrique de tube hyperfrequence a faisceau lineaire, et procede de depose associe

Also Published As

Publication number Publication date
BE731965A (de) 1969-10-01
DE1919451A1 (de) 1969-11-06
NL6906459A (de) 1969-10-28
LU58469A1 (de) 1969-07-22
GB1234517A (de) 1971-06-03
DE1919451B2 (de) 1972-07-06
FR1582070A (de) 1969-09-26

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