EP0154591B1 - Elektronenstrahlerzeuger für eine Elektronenröhre - Google Patents

Elektronenstrahlerzeuger für eine Elektronenröhre Download PDF

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Publication number
EP0154591B1
EP0154591B1 EP85400424A EP85400424A EP0154591B1 EP 0154591 B1 EP0154591 B1 EP 0154591B1 EP 85400424 A EP85400424 A EP 85400424A EP 85400424 A EP85400424 A EP 85400424A EP 0154591 B1 EP0154591 B1 EP 0154591B1
Authority
EP
European Patent Office
Prior art keywords
cathode
grid
tube
electron
axis
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
Application number
EP85400424A
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English (en)
French (fr)
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EP0154591A1 (de
Inventor
Robert Duret
Georges Fleury
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.)
Thales SA
Original Assignee
Thomson CSF SA
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 Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0154591A1 publication Critical patent/EP0154591A1/de
Application granted granted Critical
Publication of EP0154591B1 publication Critical patent/EP0154591B1/de
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/02—Electrodes; Magnetic control means; Screens
    • H01J23/06—Electron or ion guns
    • H01J23/065—Electron or ion guns producing a solid cylindrical beam

Definitions

  • the present invention relates to electron guns for electronic tubes.
  • the modulation grid is subjected to forces F proportional to the square of the electric field, and which can be expressed as follows:
  • the use of a zero release voltage leads both to a reduction in the distance d between the grid and the cathode, which is then of the order for example of a few hundredths of a millimeter, and an increase in absolute value of the blocking voltage.
  • the force F applied to the grid during blocking of the beam is then very high.
  • the resulting vibrations have the particular disadvantage of causing modulation of the beam power during the conduction stage.
  • their modulation frequency covers a very wide band and it may happen that it is precisely equal to a mechanical resonance frequency of the grid.
  • the amplitudes of the vibrations are then very high, which can cause short circuits between the grid and the cathode by bringing them into contact. These vibrations can also cause the destruction of the grid by exceeding the elastic limit of the material which constitutes it.
  • the present invention provides a simple and effective solution to the problems stated above.
  • the present invention relates to an electron gun for an electron tube, of the traveling wave tube and klystron type, comprising in particular a cathode whose emissive surface is in the form of a spherical cap, with a grid also in the vicinity of this cathode.
  • a spherical cap which can be subjected to two different potentials for modulating in power the electron beam emitted by the cathode, the cathode and the grid having concave surfaces towards the inside of the tube, characterized in that the distance between the cathode and the modulation grid increases when one approaches the axis of the tube.
  • the solution of the invention can be used regardless of the value of the release voltage, whether it is zero or positive, and regardless of the use of traveling wave tubes, or other tubes fitted with such guns.
  • the invention therefore makes it possible, while retaining the same size for the electron gun, to reduce the value of the forces exerted on the grid on the axis of the tube and in the vicinity of this axis, by increasing the distance between the cathode and the grid there.
  • the grid is held by a mechanical fixing, so there is no problem of vibrations.
  • the invention makes it possible to make the excitation force exerted at the center of the grid at least ten times weaker when the release voltage is zero.
  • Another embodiment of the invention relates to the case of electron guns, comprising in particular a cathode, with in the vicinity of this cathode, first and second grids, in the form of a spherical cap, the first grid being brought to the potential of the cathode and the second grid can be subjected to two different potentials to modulate in power the electron beam emitted by the cathode, the cathode and the grids having concave surfaces towards the inside of the tube.
  • the distance between these two grids increases when approaching the axis of the tube.
  • FIGS. 1 and 3 diagrams of two embodiments of electron guns according to the prior art
  • FIGS 2 and 4 diagrams of two embodiments of electron guns according to the invention.
  • FIG. 1 represents the diagram of an embodiment of an electron gun according to the prior art.
  • Figure 1 is a schematic longitudinal section of this gun.
  • the cathode 1 On the left in the figure, the cathode 1 is shown, the emissive surface of which is in the form of a spherical cap.
  • the modulation grid 2 In the vicinity of the cathode is the modulation grid 2 which can be subjected to two different potentials to power modulate the beam.
  • This grid is also in the form of a spherical cap.
  • the radius of curvature R G of this grid is centered on the axis of the tube XX 'at the same point C as that where the radius of curvature R K of the cathode is centered.
  • the distance between the cathode and the grid is therefore constant at all points.
  • the acceleration electrode 3 is shown diagrammatically on the right of the figure.
  • FIG. 2 represents the diagram of an embodiment of an electron gun according to the invention.
  • the grid 2 is always in the form of a spherical cap, but the radius of curvature R G of the modulation grid 2 is centered on the axis of the tube XX 'at a point Ci which is located after, if we consider the direction of movement of the electrons, the point C where the radius of curvature R K of the cathode is centered.
  • the distance between the cathode 1 and the modulation grid 2 increases when one approaches the axis of the tube. This distance is greater on the axis of the tube - dimension a - than on the periphery of the tube - dimension b.
  • the a / b ratio varies according to the characteristics of the gun such as the emission density, the distance between the modulation grid and the cathode, the surface convergence of the electron beam ... This ratio is substantially between 1, 5 and 3: 1.5 ⁇ a / b ⁇ 3.
  • Figure 3 is the diagram of another embodiment of a cannon according to the prior art. It is a barrel which differs from that of FIG. 1, because the cathode is followed by a first grid G, and a second grid G 2 , in the form of a spherical cap.
  • the first grid G is brought to the potential of cathode 1. It is a grid of the “shadow grid” type. It is the second grid G 2 which can be subjected to two different potentials allowing the power modulation of the beam.
  • the cathode and the two grids G, and G 2 have their radii of curvature centered at the same point C 2 on the axis XX '.
  • the distance between the two grids G, and G 2 and between the cathode and the first grid G 1 is constant at all points.
  • FIG. 4 represents a modification according to the invention of the barrel of FIG. 3.
  • the distance between the two grids G, and G 2 increases when one approaches the axis XX 'of the tube. It suffices to compare in the figure the distance c to the distance d.
  • the center of curvature of the second grid G 2 is a point C 3 located on the axis XX 'beyond the center of curvature C 2 of the grid G, and the emissive surface.

Landscapes

  • Microwave Tubes (AREA)

Claims (3)

1. Elektronenkanone für eine Elektronenröhre vom Typ der Wanderwellenröhren und Klystrons, insbesondere mit einer Kathode (1), deren emittierende Oberfläche die Form einer Kugelschale aufweist, mit einem in der Nähe dieser Kathode angeordneten Gitter (2), das ebenfalls die Form einer Kugelschale aufweist und auf zwei verschiedene Potentiale gelegt werden kann, um die Leistung des von der Kathode emittierten Elektronenbündels zu modulieren, wobei die Kathode (1) und das Gitter (2) zur Innenseite der Röhre konkave Oberflächen aufweisen, dadurch gekennzeichnet, dass der Abstand zwischen der Kathode und dem Modulationsgitter mit zunehmender Annäherung an die Achse der Röhre (XX') zunimmt.
2. Elektronenkanone für Elektronenröhren vom Typ der Wanderwellenröhren und Klystrons, insbesondere mit einer Kathode (1), wobei in der Nähe dieser Kathode ein erstes und ein zweites Gitter (G1, G2) in Form von Kugeischalen angeordnet sind, wobei das erste Gitter (Gi) auf das Potential der Kathode gelegt ist und das zweite Gitter (G2) auf zwei verschiedene Potentiale gelegt werden kann, um die Leistung des von der Kathode emittierten Elektronenbündels zu modulieren, wobei ferner die Kathode (1) und die Gitter (G1, G2) zur Innenseite der Röhre konkave Oberflächen aufweisen, dadurch gekennzeichnet, dass der Abstand zwischen diesen beiden Gittern mit zunehmender Annäherung an die Achse der Röhre (XX') zunimmt.
3. Kanone nach Anspruch 1, dadurch gekennzeichnet, dass das Verhältnis der Abstände zwischen der Kathode (1) und dem Modulationsgitter (2) entlang der Achse der Röhre (XX') und am Umfang der Kathode des Gitters gemessen, im wesentlichen zwischen 1,5 und 3 beträgt.
EP85400424A 1984-03-09 1985-03-05 Elektronenstrahlerzeuger für eine Elektronenröhre Expired EP0154591B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8403640A FR2561039B1 (fr) 1984-03-09 1984-03-09 Canon a electrons pour tube electronique
FR8403640 1984-03-09

Publications (2)

Publication Number Publication Date
EP0154591A1 EP0154591A1 (de) 1985-09-11
EP0154591B1 true EP0154591B1 (de) 1988-01-27

Family

ID=9301858

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85400424A Expired EP0154591B1 (de) 1984-03-09 1985-03-05 Elektronenstrahlerzeuger für eine Elektronenröhre

Country Status (4)

Country Link
US (1) US4798993A (de)
EP (1) EP0154591B1 (de)
DE (1) DE3561528D1 (de)
FR (1) FR2561039B1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2683091A1 (fr) * 1991-10-25 1993-04-30 Thomson Tubes Electroniques Dispositif de refroidissement ameliore pour tube hyperfrequence.
DE102007009890B4 (de) 2007-02-28 2025-05-28 Emcon Technologies Germany (Augsburg) Gmbh Statisches Mischelement sowie Verfahren zur Herstellung eines statischen Mischelements

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2581243A (en) * 1949-05-28 1952-01-01 Rca Corp Cathode of electron beam devices
BE530043A (de) * 1953-07-02
US3377492A (en) * 1965-08-03 1968-04-09 Hughes Aircraft Co Flood gun for storage tubes having a dome-shaped cathode and dome-shaped grid electrodes
US3500110A (en) * 1967-08-23 1970-03-10 Raytheon Co Noncurrent intercepting electron beam control element
US3852633A (en) * 1972-12-13 1974-12-03 Varian Associates Gridded electron gun
GB1507544A (en) * 1975-12-29 1978-04-19 English Electric Valve Co Ltd Linear beam tubes
US4321505A (en) * 1978-07-24 1982-03-23 Varian Associates, Inc. Zero-bias gridded gun
US4593230A (en) * 1982-03-29 1986-06-03 Litton Systems, Inc. Dual-mode electron gun
US4583021A (en) * 1983-04-18 1986-04-15 Litton Systems, Inc. Electron gun with improved cathode and shadow grid configuration

Also Published As

Publication number Publication date
FR2561039A1 (fr) 1985-09-13
US4798993A (en) 1989-01-17
FR2561039B1 (fr) 1987-04-03
DE3561528D1 (en) 1988-03-03
EP0154591A1 (de) 1985-09-11

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