US3649868A - Pulse electron gun - Google Patents

Pulse electron gun Download PDF

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Publication number
US3649868A
US3649868A US22892A US3649868DA US3649868A US 3649868 A US3649868 A US 3649868A US 22892 A US22892 A US 22892A US 3649868D A US3649868D A US 3649868DA US 3649868 A US3649868 A US 3649868A
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Prior art keywords
cavity
electron
electrodes
resonator
source
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Expired - Lifetime
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US22892A
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English (en)
Inventor
Andre Bensussan
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Thales SA
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Thomson CSF 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
    • H01J3/021—Electron guns using a field emission, photo emission, or secondary emission electron source
    • 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
    • H01J3/023—Electron guns using electron multiplication
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/34—Photoemissive electrodes
    • H01J2201/342—Cathodes

Definitions

  • the present invention relates to a novel electron gun operating on short pulses, more particularly intended for electron accelerator devices of the kind employed in nuclear research applications.
  • Such accelerators have in essence a triode-type structure whose electron-emissive cathode and whose control grid are, in the conventional way, placed at a negative potential in relation to the anode which is in this case the accelerator structure itself.
  • this accelerator structure the dimensions of which can attain several hundred meters in typical cases, is maintained at earth potential and the consequence of this is that the cathode-grid arrangement is placed at a negative potential in relation to earth, which potential is equivalent in absolute value to the anode voltage, i.e., is usually very high indeed.
  • This arrangement is supplied by electrical power sources, both in continuous operation and in pulse operation, which are consequently likewise placed at the same very high potential in relation to earth.
  • conventional-type electron guns comprise, for the purpose of applying the pulse modulation, one or more electrodes whose relative capacitances and inductances set a bottom limit on the pulse duration.
  • an electron gun for electron discharge devices comprising: an evacuated enclosure including a photoemissive target capable of generating an electron current, means for amplifying said electron current, and means for picking up said electron current for subsequent use; a light source; and optical means for transmitting said light to said target for producing said electron current.
  • FIG. 1 illustrates the assembly of a short-pulse electron gun circuit for direct acceleration voltage
  • FIG. 2 illustrates a short-pulse electron gun circuit for alternating acceleration voltage.
  • the assembly illustrated in FIG. 1 comprises a short-pulse generator 1 supplying a laser-type light source 2.
  • the latter is connected through a light transmission device 3 which can be for example, optical fibers or an optical system employing mirror and/or prisms and lenses, photoemissive targets as 4 which produce electrons and are fixed to the wall of a sealed metal enclosure 5.
  • the electrons thus emitted impinge upon a first of a series of annular electrodes 6 referred to in the art as dynodes," and positioned as shown in FIG. 1.
  • Their surface is constituted by a material having a high secondary electron emission coefficient and they are biased by a voltage source comprising an electric motor 7 which, through the medium of an insulating sleeve 8, drives an alternator 9, the alternating voltage from which is converted to a direct voltage by a rectifier l and as then applied to the electrodes 6 through an insulating lead throughs 11.
  • a high-voltage generator 12 brings the electron gun assembly to a negative voltage in relation to the body of the accelerator 13. The latter is rendered vacuumtight and is connected to the gun assembly through a sealed insulating sleeve 14.
  • a casing 15 surrounds the assembly of elements which are at high voltage. It can be filled, if required with an insulating gas of high breakdown voltage such as, for
  • Insulating sealing sleeves such as sleeves l6, prevent any gas leakage where connections through the wall of container 15 exist.
  • the pulse generator 1 supplies the lasertype light source 2.
  • the light produced by the latter is channelled through light conducting channels 3 to the transparent photoemissive targets 4.
  • the electrons emitted are attracted by the first annular electrode 6, which is placed at a positive potential in relation to said targets, by the rectifier 10, the electrons being incident upon said target in accordance with a trajectory of the kind marked 17 and producing consequent secondary electrons in substantially larger numbers than the numbers of incident electrons. Due to the material of which the surface of said electrode is made, the phenomenon described takes place in cumulative way from electrode to electrode, each of the latter being placed at a higher potential than the particular preceding one, considered in the order of the respective paths 18 in which the electrons are developed.
  • the shape of the electrode 6 is such that it creates, in combination with the electric field prevailing between the enclosure 5 and the tubular body of the accelerator 13, electric forces resulting in electron trajectories such as 19 for purposes of subsequent utilizattron.
  • FIG. 2 illustrates a variant embodiment of the invention.
  • This embodiment comprises a short-pulse generator I, supplying a laser-type light source 2, light conductors 3 of the kind already described, photoemissive targets producing electrons and fixed to the wall of a sealed metallic enclosure 5, a series of annular electrodes 6 whose surfaces are made of a material having a high secondary electron emission coefficient, the appropriate biasing of these electrodes being provided by an UHF electromagnetic power source 20, for example a magnetron, and this magnetron being supplied by the power pulse generator 21, the pulses of which are synchronized with those of the generator 1 by a pilot device 22.
  • the radio frequency power produced by the source 20 is introduced, through the line 23 and the coupling probe 24, into the metal cavity, the dimensions of which latter have been calculated so that it goes into resonance in the mode E 010.
  • the magnetic lines of force there are circles centered on the axis of revolution of the cavity and have their planes parallel with the mutually opposite flat faces, while the electric lines of force then are parallel to the axis of revolution of the cavity.
  • the electrons created by the photoemissive targets 4 are subjected to this alternating electric field and experience an accelerating force; if the instant at which the electrons are generated by the targets 4 coincides with that at which the electric field is in an accelerating state, and if the intervals between the annular electrodes are so chosen that the time taken by the electrons to pass from one dynode to the next is equal to half the periodicity of the high-frequency oscillation, then the electrons will describe trajectories 17. As in the case of electron gun shown in FIG. 1, there will be an increase in the current initially generated by the targets.
  • This mechanism of generation of a beam is sometimes present as an undesired phenomenon, in the resonant cavities of certain electron tubes and is then known as multipactor effect.” However, in the present invention, this very effect is put to use.
  • the alternating electric field prevailing in the resonant cavity can itself perform the function of guiding the electrons towards the anode. It has a maximum value on the axis of revolution and can reach values comparable with that of the DC voltage employed in the electron gun shown in FIG. 1.
  • the frequency could be in order of 1,000 mHz. with a peak power of 75 kw., in which case the resonant cavity would have a diameter of 25 cm. and a total thickness of cm.; the axial distance between the elements 25 and 26, is then in the order of 2.5 cm.; under these circumstances, the maximum acceleration voltage at the extraction output of the gun, would be in the order of 75 kv.
  • the invention is not limited to the embodiments described and shown, which were given only by way of examples.
  • the invention is not limited to electron accelerators and can be applied to any electronic device in which a short-pulse electron beam is employed.
  • An electron gun for an electron discharge device which comprises:
  • a plurality of photoemissive electron sources disposed about the periphery of one end symmetry, said cylindrical cavity resonator, said electron sources being capable of generating a primary electron beam within said cavity;
  • annular electrodes coaxial with said axis of symmetry, successive annular electrodes having an increased radius, the annular electrode closest to the periphery of said resonator having the greatest radius, each of said electrodes being capable of emitting secondary electrons;
  • means located proximate said axis of symmetry, for extracting said primary beam and the beam comprised of the secondary electrons from said plurality of annular electrodes, for subsequent utilization.

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  • Particle Accelerators (AREA)
US22892A 1969-03-31 1970-03-26 Pulse electron gun Expired - Lifetime US3649868A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR6909674A FR2038845A5 (xx) 1969-03-31 1969-03-31

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US3649868A true US3649868A (en) 1972-03-14

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US (1) US3649868A (xx)
DE (1) DE2015124A1 (xx)
FR (1) FR2038845A5 (xx)
NL (1) NL7004228A (xx)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4207452A (en) * 1977-04-25 1980-06-10 Tokyo Shibaura Electric Co., Ltd. Activated gas generator
US4341427A (en) * 1980-06-30 1982-07-27 Rca Corporation Method for stabilizing the anode sensitivity of a photomultiplier tube
US4777403A (en) * 1987-05-28 1988-10-11 Stephenson K E Dynode structures for photomultipliers
US5150067A (en) * 1990-04-16 1992-09-22 Mcmillan Michael R Electromagnetic pulse generator using an electron beam produced with an electron multiplier
US5374864A (en) * 1989-08-14 1994-12-20 Detector Technology, Inc. Electron multiplier with increased-area channel
EP0902959A1 (en) * 1996-05-22 1999-03-24 Schwartz, Ansel M. Multi-stage electron gun having an electrostatic cavity

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4715038A (en) * 1985-05-20 1987-12-22 The United States Of America As Represented By The United States Department Of Energy Optically pulsed electron accelerator

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2210034A (en) * 1935-11-08 1940-08-06 Emi Ltd Electron multipler
US2925522A (en) * 1955-09-30 1960-02-16 High Voltage Engineering Corp Microwave linear accelerator circuit
US3201640A (en) * 1962-03-07 1965-08-17 Itt Electron gun in the form of a multipactor
US3215844A (en) * 1962-08-02 1965-11-02 Bell Telephone Labor Inc Broadband output coupler for photomultiplier system
US3233140A (en) * 1961-07-25 1966-02-01 Univ Illinois Crossed-field dynamic electron multiplier
DE1230924B (de) * 1963-02-25 1966-12-22 Telefunken Patent Sekundaerelektronenvervielfacher mit Photokathode
US3349273A (en) * 1965-11-12 1967-10-24 Gaus Electrophysics Photoelectric transducer head
US3388282A (en) * 1965-03-29 1968-06-11 Hallicrafters Co Biased crossed field dynamic electron multiplier
US3435233A (en) * 1966-03-24 1969-03-25 Hughes Aircraft Co Gain control system for photomultiplier systems

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2210034A (en) * 1935-11-08 1940-08-06 Emi Ltd Electron multipler
US2925522A (en) * 1955-09-30 1960-02-16 High Voltage Engineering Corp Microwave linear accelerator circuit
US3233140A (en) * 1961-07-25 1966-02-01 Univ Illinois Crossed-field dynamic electron multiplier
US3201640A (en) * 1962-03-07 1965-08-17 Itt Electron gun in the form of a multipactor
US3215844A (en) * 1962-08-02 1965-11-02 Bell Telephone Labor Inc Broadband output coupler for photomultiplier system
DE1230924B (de) * 1963-02-25 1966-12-22 Telefunken Patent Sekundaerelektronenvervielfacher mit Photokathode
US3388282A (en) * 1965-03-29 1968-06-11 Hallicrafters Co Biased crossed field dynamic electron multiplier
US3349273A (en) * 1965-11-12 1967-10-24 Gaus Electrophysics Photoelectric transducer head
US3435233A (en) * 1966-03-24 1969-03-25 Hughes Aircraft Co Gain control system for photomultiplier systems

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4207452A (en) * 1977-04-25 1980-06-10 Tokyo Shibaura Electric Co., Ltd. Activated gas generator
US4341427A (en) * 1980-06-30 1982-07-27 Rca Corporation Method for stabilizing the anode sensitivity of a photomultiplier tube
US4777403A (en) * 1987-05-28 1988-10-11 Stephenson K E Dynode structures for photomultipliers
US5374864A (en) * 1989-08-14 1994-12-20 Detector Technology, Inc. Electron multiplier with increased-area channel
US5150067A (en) * 1990-04-16 1992-09-22 Mcmillan Michael R Electromagnetic pulse generator using an electron beam produced with an electron multiplier
EP0902959A1 (en) * 1996-05-22 1999-03-24 Schwartz, Ansel M. Multi-stage electron gun having an electrostatic cavity
EP0902959A4 (en) * 1996-05-22 1999-08-18 Schwartz Ansel M MULTI-STAGE ELECTRONIC CANNON WITH AN ELECTROSTATIC CAVITY

Also Published As

Publication number Publication date
FR2038845A5 (xx) 1971-01-08
NL7004228A (xx) 1970-10-02
DE2015124A1 (de) 1970-10-15

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