US3859552A - Electron beam generator for transit-time electron discharge tubes - Google Patents

Electron beam generator for transit-time electron discharge tubes Download PDF

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Publication number
US3859552A
US3859552A US331809A US33180973A US3859552A US 3859552 A US3859552 A US 3859552A US 331809 A US331809 A US 331809A US 33180973 A US33180973 A US 33180973A US 3859552 A US3859552 A US 3859552A
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Prior art keywords
cathode
grid
electron beam
section
partial
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Expired - Lifetime
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US331809A
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English (en)
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Richard Hechtel
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Siemens AG
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Siemens AG
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    • 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 electronbeamv generators, and more particularly to electron beam genera tors for transit time electronldischarge tubes having a cathode for emission of an electron beam, a control grid spaced from the cathode, and'an anode, and which features independent control of emission of an area surrounding the central portion of the cathode with referent power levels.
  • the two-power levels may differ" from one another, for example by a factor of or 10.
  • the lower power level is used'in normal operation for reasons of power economy, and thehigher power level is only used under 3ertain tir'cumstances, 5 .g.' Zn the event of interference from another transmittent
  • this type of power regulation can only be effectedthrough a-cont'rol of the electron beam current.
  • a change in the beam voltage is unsuitable for this purpose,because-of-thephasere lationship which must-be mai'nt'aine dgbe'tween the elec-;
  • An object of the invention is to provide an electron-- following relationship holds "where F1 is'the arjea 'covered by the inner grid section grids, one of which is a so-called shadow grid which absorbs no current'are only a comparatively small amount of current; A 'double grid of this kind is described, for example, in German published application 1,764,860.
  • the invention can be'practiced by splitting the area of jfthejcontrol grid andelectrically insulating the two partial areas from each other. In this manner, power level control of transit time tubes can be carried out by controlof the emission from the cathode of the electron beam generator, more specifically by applying potentials of different polarity to that of the cathode to the section of the.
  • control grid v which surrounds the central area.
  • This kind of current control requires only relatively small voltagechanges in order to switch the beam current from one value to another and is free ofany undesirable secondary electron-optical effects. It can be applied both in electron beam generators of the continuous-rating type, and also to pulsed electron beam generators.
  • the electron beam generator has a control grid which comprises a first partial grid section surro'unding and mechanically-and electrically isolated from a second partial grid section which covers the central area of the emissive surface of the cathode.
  • An electron beam generator of this form in which ".the inner partial grid section is 'circularand the outer section is'ring-shaped, has the following properties.
  • the beam current I is determined, in accordance with the applied potentials, by the relative areas'of the' two ,partial grid sections. If I, is the smaller of the two currents and l -is the larger of the twocurrents, then the 1 "As far as'the beam current I is concerned, three differentoperating conditionslcan be distinguished.
  • the invention resides in the provision of an electron-- beam generator for transit timeitubes, comprising a v cathode for the emission ofanelectron beam, a control grid spaced from the cathode,'and an anode, wherein the control grid comprises"asectionlwhich' surroundsa" central portion of the emissivearea of the cathod'ef whereby the emission from the areaof the cathode sur'-; I rounding the central portion can be controlled independently of the emission from-the central portion f
  • the section of the control grid which'surrounds the central portion of the emissive area of the cathode is not necessarily an annular'ring, since the electron beam may not have a circulancross section, and may, for excontrol grid or grids,
  • ' tron beam generator has axial symmetry, in which 'the The inner partial grid section is positive and the outer partial grid section. is negative with respect to thecath ode;
  • the voltage on the inner control grid section, in 1 relationto the cathode, is'about l/25th to l/50th of the anod e voltage.
  • the voltage on the external partial grid section is of the same order magnitude, but of negative p ol'arity.”
  • Both-partial grid sections are positive with respect to I the cathode.
  • the voltages'applied to these grid sections are about l/25thtopl/50th of the, anode voltage.
  • the elecjjfijrst; partial grid section is in the form of an annular ring surrounding the second partial grid section which has a circular periphery. Consequently, and in accordance with equation 1, the following approximation holds true, provided that the radius of curvature of the cathode surface is not too small:
  • D is the diameter of the inner partial grid section and D is the diameter of the cathode.
  • control grid has only one section and surrounds the central portion of the emissive area of the cathode which projects toward the anode so as to be flush with the surface of the control grid.
  • This embodiment is particularly suitable for a continuous-rating electron beam generator.
  • the electron beam generator behaves in a manner similar to that of one using an inner partial grid section, as far as two possible beam currents are concerned, but in order to completely block the beam current, the anode potential must be changed rather than the cathode potential.
  • FIG. 1 is a longitudinal sectional view of a first embodiment of an electron beam generator
  • FIG. 2 is a plan view of the inner grid of the apparatus illustrated in FIG. 1;
  • FIG. 3 is a plan view of the outer grid of the apparatus illustrated in FIG. 1;
  • FIG. 4 is a longitudinal sectional view of a second embodiment of an electron beam generator
  • FIG. 5 is a plan view of the outer partial grid of the embodiment illustrated in FIG. 4;
  • FIG. 6 is a longitudinal sectional view of a third embodiment of an electron beam generator
  • FIG. 7 is a plan view of the inner partial grid structure of the control grid of the apparatus illustrated in FIG.
  • FIG. 8 is a plan view of the outer partial grid of the control grid of the apparatus illustrated in FIG. 6;
  • FIG. 9 is a plan view of the shadow grid of the apparatus illustrated in FIG. 6.
  • the tube wall 11 is interrupted at appropriate points by insulating ceramic cylinders 9.
  • the supporting bolts of which the bolts 23 and 24 are illustrated in FIG. 1, rest upon a support cylinder 26.
  • the cathode itself is conventional and comprises a heating element 4 having a current supply lead 22 embedded in a ceramic disc 21, the mounting cylinder 26 resting on a base plate 10, and a plurality of radiation shields 6.
  • FIG. 3 is a plan view of the outer partial grid 18 and its mounting apparatus.
  • the partial grid 18 also comprises a number of radially disposed spokes 16 attached at their inner ends to a circular ring 17 and whose outer ends terminate in a second carrier plate 8 having good thermal conductivity.
  • the partial grid 18 is provided with a plurality of openings 32 for receiving the supporting stay 14 of the inner partial grid 15.
  • the openings 28 in the carrier plate 18 are provide for the passage of the supporting bolts 23, 24, 25.
  • FIG. 4 which also has an axially-symmetrical electron beam generator, there is no inner partial grid.
  • a shadow grid 20 which is supported by the support cylinder 26 of the focusing electrode 3 and which is at cathode potential when the electron beam generator is operating.
  • This double grid structure and the emissive area of the cathode l are curved and the curve surfaces have a common center of curvature.
  • a focusing anode 30, which has an appropriate electron-optical shape, draws an electron current I, when the control grid 2 has a negative potential with respect to the cathode 1 applied thereto, and draws an electron current I from the cathode surface if the potential is positive. All of the other designed features correspond to those illustrated in FIG. 1. The use of this embodiment of the invention is recommended if the transit time tube is operating on a continuous-rating basis.
  • the grid elements comprise a plurality of radial spokes 16 which, as in the outer partial grid illustrated in FIG. 3, terminate in the carrier plate 8 having the openings 28 for receiving the bolts 23, 24, 25.
  • FIG. 6 is a schematic longitudinal sectional view of the central part of a third embodiment of an electron beam generator which is primarily confined to the cathode surface and the control grid structure.
  • the electron beam generator in this embodiment is again axially symmetrical and employs a double grid (control grid and shadow grid) the surfaces of which and the cathode surface have a common center of curvature. As viewed from the center curvature, the control grid and the shadow grid elements are in alignment.
  • the beam current boundaries have been illustrated by broken lines to correspond to the two different power levels of the tube, the boundary a representing the partial current I, and the boundary b representing the full current I FIGS.
  • the two partial grids of the control grid are formed such that the shadow grid, while in full alignment, can take the form ofa single mechanical structure which is therefore relatively simple to manufacture. All of the grids comprise predominately ringshaped elements with only a few radial spokes. If the shadow grid is placed at cathode potential and the two partial grids at a moderately high positive potential with respect to the cathode (l/lOth to l/lOOth of the anode voltage), then the current drawn by the partial grids is negligible. Typical values are between 0.01 and 0.1 percent of the total cathode current.
  • the rules hereinbefore listed apply to the three operating conditiOnS (I0, [1,
  • the electron beam generator need not be axially-symmetrical, but can have a form which is suitable for the production of flat ribbon type beams.
  • the invention can be applied in a corresponding manner if the transit time tubes are to be operated not merely in two, but in several operating conditions.
  • An electron beam generator for transit time tubes with single beam operation at more than one power level and different beam cross sections corresponding to respective power levels and current intensities comprising: a cathode for the emission of a single beam; a control grid spaced from said cathode; and an anode for receiving the electron beam, said control grid comprising a section which surrounds a central portion of the emissive area of said cathode for selectively receiving control potential for either blocking or permitting emission from the area of the cathode surrounding the central portion independently of the emission from the central portion to provide single beam operation with or without emission from said surrounding portion.
  • control grid comprises a first partial grid section and a second partial grid section, said first partial grid section surrounding and mechanically and electrically isolated from said second partial grid section, said second partial grid section covering the central area of the emissive surface of said cathode.
  • An electron beam generator for transit time tubes which operate at more than one power level, comprising: a cathode for the emission of an electron beam; a control grid spaced from said cathode; and an anode for receiving the electron beam, said control grid comprising a section which surrounds a central portion of the emissive area of said cathode for selectively receiving control potential for controlling the emission from the area of the cathode surrounding the central portion independently of the emission from the central portion, said control grid comprising a first partial grid section and a second partial grid section, said first partial grid section surrounding and mechanically and electrically isolated from said second partial grid section, said section partial grid section covering the central area of the emissive surface of said cathode, wherein said cathode is an axially-symmetrical cathode, wherein said second partial grid section comprises a plurality of radiallydisposed spokes, a circular ring connecting said plurality of radially disposed spokes together, some of said spokes extending beyond said ring as supporting stays,
  • An electron beam generator as claimed in claim 1, wherein the emissive surface of said cathode and said control grid surface are concave and have a common center of curvature.
  • An electron beam generator as claimed in claim 5, comprising a shadow grid disposed between said control grid and said cathode for operation at cathode potential, said shadow grid including grid elements which are aligned with those of said control grid as viewed from said cathode or from said common center of curvature.
  • An electron beam generator as claimed in claim 1, comprising a shadow grid disposed between said control grid and said cathode for operation at cathode potential, said shadow grid including grid elements which are aligned with those of said control grid.

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  • Electron Sources, Ion Sources (AREA)
US331809A 1972-03-02 1973-02-12 Electron beam generator for transit-time electron discharge tubes Expired - Lifetime US3859552A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2210160A DE2210160C3 (de) 1972-03-02 1972-03-02 Elektronenstrahlerzeugersystem für Laufzeitröhren

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US3859552A true US3859552A (en) 1975-01-07

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US (1) US3859552A (de)
DE (1) DE2210160C3 (de)
FR (1) FR2173919B1 (de)
GB (1) GB1357469A (de)
IT (1) IT972629B (de)
SE (1) SE386005B (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2535724A1 (de) * 1975-08-09 1977-02-17 Licentia Gmbh Elektronenstrahlroehre
US4023061A (en) * 1976-01-19 1977-05-10 Varian Associates Dual mode gridded gun
US4321505A (en) * 1978-07-24 1982-03-23 Varian Associates, Inc. Zero-bias gridded gun
WO1985001150A1 (en) * 1983-08-30 1985-03-14 Hughes Aircraft Company Dual-mode electron gun with improved shadow grid arrangement
US4593230A (en) * 1982-03-29 1986-06-03 Litton Systems, Inc. Dual-mode electron gun
US4745324A (en) * 1986-05-12 1988-05-17 Litton Systems, Inc. High power switch tube with Faraday cage cavity anode
US4748369A (en) * 1986-04-10 1988-05-31 Star Microwave Electron gun assembly useful with traveling wave tubes
CN104078296A (zh) * 2014-07-02 2014-10-01 南京三乐电子信息产业集团有限公司 一种高装配精度的栅控电子枪

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL43254A (en) * 1972-09-28 1976-02-29 Varian Ass Ciates Gridded electron gun employing a concave cathode emitter
US5990622A (en) * 1998-02-02 1999-11-23 Litton Systems, Inc. Grid support structure for an electron beam device

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2694159A (en) * 1949-03-22 1954-11-09 Bell Telephone Labor Inc Microwave amplifier
US3121181A (en) * 1959-07-09 1964-02-11 Philips Corp Plural beam electron gun
US3132275A (en) * 1960-05-31 1964-05-05 Eitel Mccullough Inc Electron gun and cathode heater assembly therefor
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
US3484645A (en) * 1967-03-06 1969-12-16 Us Army Non-intercepting grid structure for an electron tube
US3500110A (en) * 1967-08-23 1970-03-10 Raytheon Co Noncurrent intercepting electron beam control element
US3558967A (en) * 1969-06-16 1971-01-26 Varian Associates Linear beam tube with plural cathode beamlets providing a convergent electron stream
US3651360A (en) * 1968-04-26 1972-03-21 Alcatel Heurtey Sa Triode electron gun with positive grid and modular cathode

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2694159A (en) * 1949-03-22 1954-11-09 Bell Telephone Labor Inc Microwave amplifier
US3121181A (en) * 1959-07-09 1964-02-11 Philips Corp Plural beam electron gun
US3132275A (en) * 1960-05-31 1964-05-05 Eitel Mccullough Inc Electron gun and cathode heater assembly therefor
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
US3484645A (en) * 1967-03-06 1969-12-16 Us Army Non-intercepting grid structure for an electron tube
US3500110A (en) * 1967-08-23 1970-03-10 Raytheon Co Noncurrent intercepting electron beam control element
US3651360A (en) * 1968-04-26 1972-03-21 Alcatel Heurtey Sa Triode electron gun with positive grid and modular cathode
US3558967A (en) * 1969-06-16 1971-01-26 Varian Associates Linear beam tube with plural cathode beamlets providing a convergent electron stream

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2535724A1 (de) * 1975-08-09 1977-02-17 Licentia Gmbh Elektronenstrahlroehre
US4023061A (en) * 1976-01-19 1977-05-10 Varian Associates Dual mode gridded gun
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
WO1985001150A1 (en) * 1983-08-30 1985-03-14 Hughes Aircraft Company Dual-mode electron gun with improved shadow grid arrangement
US4553064A (en) * 1983-08-30 1985-11-12 Hughes Aircraft Company Dual-mode electron gun with improved shadow grid arrangement
US4748369A (en) * 1986-04-10 1988-05-31 Star Microwave Electron gun assembly useful with traveling wave tubes
US4745324A (en) * 1986-05-12 1988-05-17 Litton Systems, Inc. High power switch tube with Faraday cage cavity anode
CN104078296A (zh) * 2014-07-02 2014-10-01 南京三乐电子信息产业集团有限公司 一种高装配精度的栅控电子枪
CN104078296B (zh) * 2014-07-02 2016-09-14 南京三乐电子信息产业集团有限公司 一种高装配精度的栅控电子枪

Also Published As

Publication number Publication date
DE2210160B2 (de) 1974-09-12
DE2210160C3 (de) 1975-04-30
FR2173919B1 (de) 1978-06-09
FR2173919A1 (de) 1973-10-12
IT972629B (it) 1974-05-31
SE386005B (sv) 1976-07-26
DE2210160A1 (de) 1973-09-13
GB1357469A (en) 1974-06-19

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