US3780336A - High power beam tube having depressed potential collector containing field-shaping probe - Google Patents

High power beam tube having depressed potential collector containing field-shaping probe Download PDF

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Publication number
US3780336A
US3780336A US00283431A US3780336DA US3780336A US 3780336 A US3780336 A US 3780336A US 00283431 A US00283431 A US 00283431A US 3780336D A US3780336D A US 3780336DA US 3780336 A US3780336 A US 3780336A
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Prior art keywords
collector
mouth
probe
cavity
electrons
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Expired - Lifetime
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US00283431A
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English (en)
Inventor
R Giebeler
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Varian Medical Systems Inc
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Varian Associates Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/02—Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators
    • 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
    • H01J23/027—Collectors

Definitions

  • a tapered conductive probe is a ti- [511 I t Cl 23/02 ally disposed within the beam collector for coopera- [58 i 3 g 5 tion with a collector focus electrode structure to shape earc b the equipotentials at the mouth of the fly-trap beam collector, in the presence of space charge depression 56 1 Ref 8 C1 d within the collector, such as to retain laminar electron er nces I flow and uniform current density transversely across UNITED STATES PATENTS the beam as the beam decelerates and expands into ,482 7/1969 P i st 315/538 X the beam collector structure, whereby increased de- 2,958,804 ll/l960 Badger 6t 3.] 3l5/5.38 X pressed collector efficiency is obtained 3,644,778 2/1972 Mihran et al.
  • the principal object of the present invention is the provision of an improved high power beam tube having a depressed beam collector.
  • the fly-trap depressed beam collector is provided with a centrally disposed tapered electrically conductive probe for co operation with the collector focusing electrode structure at the mouth of the fly-trap collector for shaping the equipotentials at the mouth of the fly-trap collector, in the presence of a substantial space charged depression within the collector, such that at the mouth of the collector the decelerating beam maintains laminar electron flow of generally uniform transverse current density, whereby the efficiency of the tube is substantially increased.
  • the tapered collector probe includes a free end tip portion disposed substantially at the mouth of the fly-trap collector, the tip of the probe having a cross-sectional area of less than 1 percent of the cross-sectional area of the mouth of the collector, such that less than 1 percent of the beam is intercepted on the tip of the collector probe.
  • FIG. 1 is a longitudinal sectional view. partly in elevation, of an electron beam tube incorporating features of the present invention.
  • FIG. 2 is an enlarged plot of equipotentials for that portion of the structure of FIG. 1 delineated by line 22 and depicting the electron trajectories for a decelerating beam of amps at 95 percent collector de pression for a beam having a beam voltage of kV.
  • FIG. 1 there is shown the beam tube 1 of the present invention.
  • the tube includes a Pierce type gun assembly 2 at one end of the tube for projecting a beam of electrons 3 through an accelerating anode electrode 4 to a fly-trap beam collector 5 at the terminal end of the beam path.
  • a spherically concave control grid 11 is disposed overlaying the shadow grid 9 with the apertures of the control grid being aligned in registration with the apertures in the shadow grid 9.
  • the control grid 11 is spaced from the cathode emitting; surface 7 by a relatively short distance, as of 0.039 inch, to define a multiplicity of Pierce guns when a positive potential, relative to the cathode, is applied to the control grid 11.
  • the control grid 11 is supported in electrically insulative relation relative to the thermionic cathode 6, as by an in sulator mounted to the surrounding.
  • focus electrode 8 is preferably operated at cathode potential.
  • the control grid 11, which faces the accelerating electrode 4, is pulsed with a potential which is a small fraction, as of l/30th to I/50th, of the accelerating potential for controlling the flow of electrons from the emitter 6 through the accelerating electrode 4.
  • a cylindrical high voltage insulator assembly 15 holds off the high voltage applied between cathode 6 and accelerating electrode 4 and, in addition, permits certain of the various independent electron gun potentials to be applied to various electrodes thereof.
  • a similar cylindrical high voltage insulator 16 is sealed between the aecelerating electrode 4 and the depressible beam collector structure 5 to form a portion of the tubes vacuum envelope and to permit the collector 5 to be operated at a depressed potential nearly equal to the cathode emitter potential, whereby the forward conduction potential drop of the tube 1 is but a small percentage, as of l to percent, of the accelerating electrode potential.
  • the beam collector structure 5 includes a beam col lecting cavity portion 17 for collecting the beam on the interior surfaces thereof and a centrally apertured end wall 18 defining a beam entrance passageway 19 (mouth) which is of constricted cross-sectional area compared to the collector portion 17 to prevent escape of secondary electrons from the collector back toward the accelerating electrode 4.
  • An annular conductive beam focus nose member 21 projects from the collector wall 18 toward the accelerating electrode 4 for properly shaping the beam decelerating electric field equipotential surfaces at the beam entrance passageway 19.
  • the cross-sectional area of the tip of the probe 20 is preferably less than I percent of the cross-sectional area of the mouth 19 of the collector and, in a typical example, the tip area of the probe is 0.25 percent of the area of the mouth 19 when the maximum voltage between the accelerating anode 4 and the collector is 155 kV.
  • the collector probe 20 has a half-cone angle of less than 20 and in a preferred embodiment the half-cone angle is 9.
  • the cone 20 is sealed to the closing endwall of the collector 5, as by a brazed joint therebetween, to form a gas-tight seal.
  • the cone 20 is preferably hollow and contains an internal conical baffle 22 spaced from the inside wall of the cone 20 to define a fluid coolant passageway into the cone through the center of the conical baffle 22 and back out of the probe 20 via the annular space between the outside of the baffle 22 and the inside wall of the of the conical probe 20.
  • the collector probe 20 is shown as being conductively connected to the collector 5 for operation at the same potential
  • the collector probe 20 in an alternative embodiment, is connected to the collector cavity 5 via the intermediary of an electrical insulator member as of alumina ceramic (not shown) to hold off a potential applied between the collector probe 20 and the collector 5.
  • a few kV potential applied to the probe 20 relative to the potential of the collector 5 may be utilized for adjusting the equipotentials within the collector 5 and at the mouth 19 of the collector 5 to aid in obtaining a uniform spread of the electron beam in the collector and to aid in control of the path of the secondary electrons to capture them within the fly-trap collector.
  • the probe 20 and beam collector nose portion 21 are formed and arranged such that the equipotential surface, corresponding to the potential of the collector, namely 7.75 kV, bends across the mouth 19 of the collector in a spherically concave shape generally conforming to a mirror image of the concave shape of a similar equipotential located on the opposite side of the accelerating anode just overlaying the the cathode emitting surface 7.
  • the probe 20 and collector focus nose portion 21 are dimensioned and arranged to maintain laminar electron flow in the decelerating region of the electron beam as the beam expands into the mouth of the collector l9. ln addition, the electrodes 21 and 20 are arranged such that the expanding electron beam, at the mouth 19 of the collector 5, maintains a generally uniform current density taken transversely of the beam. The uniformity of the spacing of the individual electron trajectories in the plot of FIG. 2 shows that laminar flow and uniform current density in the beam are maintained as the beam expands into the collector.
  • the cone angle of the collector probe 20 is chosen such that a minimum number of electrons are collected on the probe and such that the space charged depression region is shaped to maintain the desired equipotential surfaces at the collector mouth 19.
  • the shallow angle of incidence of primary electrons collected on the probe 20 and their points of collection well within the fly-trap collector further assure that secondary electrons liberated by collision of incident primary electrons are scattered off the probe 20 with trajectories which will take the secondary electrons back into the collector cavity, rather than backstreaming along the beam path to the anode 4 where they would be'collected at relatively high anode potential, thereby drastically reducing the efficiency of the tube.
  • the linear beam tetrode switch tube 1 of FIG. 1 with electrodes shaped as aforedescribed has provided 95 percent efficiency when operated as a switch tube with a monoenergetic beam 3 under conditions of 98 percent collection of the beam current at 97 percent collector depression and with peak current levels to 100 amperes at depression voltages (anode to collector) up to 140 kV.
  • high power is defined to mean power in excess of a 100 kW peak or 100 watts average.
  • thermionic cathode emitter means having a concave emitting surface for thermionically emitting electrons; centrally apertured accelerating anode means spaced from said emitter means and shaped for drawing a convergent stream of electrons through the central aperture of said anode in a substantially nonintercepting manner to form a laminar flow electron beam of generally uniform current density taken transversely across the beam path; collector means disposed at the terminal end of the beam path for collecting the electron beam, said collector operating at a depressed potential in respect to said anode means and having an electrically conductive cavity with a constricted mouth for receiving said beam in said cavity and for inhibiting egress of secondary and reflected electrons from said cavity, collector focusing means disposed at the mouth of said collector, and tapered conductive probe means disposed axially within said collector cavity, said probe having a terminating free end portion disposed approximately at the mouth of said collector cavity, said free end portion having a half-cone angle of less than 20 and a free end tip portion
  • said cathode emitter has a generally spherically concave emitting surface, and wherein the decelerating electric field equipotential essentially at the mouth of said collector means is shaped by said collector focusing means and said probe means in the presence of space charge within said collector cavity to be approximately a mirror image of the corresponding equipotential overlaying the emitting surface of said cathode emitter.

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  • Microwave Tubes (AREA)
  • Electron Sources, Ion Sources (AREA)
US00283431A 1972-08-24 1972-08-24 High power beam tube having depressed potential collector containing field-shaping probe Expired - Lifetime US3780336A (en)

Applications Claiming Priority (1)

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US28343172A 1972-08-24 1972-08-24

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US3780336A true US3780336A (en) 1973-12-18

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US (1) US3780336A (enrdf_load_stackoverflow)
JP (1) JPS5720656B2 (enrdf_load_stackoverflow)
CA (1) CA999332A (enrdf_load_stackoverflow)
DE (1) DE2341503A1 (enrdf_load_stackoverflow)
FR (1) FR2197228B1 (enrdf_load_stackoverflow)
GB (1) GB1389985A (enrdf_load_stackoverflow)
IL (1) IL42924A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3925701A (en) * 1973-11-08 1975-12-09 Siemens Ag Electron beam collector electrode for an electron beam tube
US4179615A (en) * 1977-09-07 1979-12-18 Gesellschaft fur Schwerionenforschung mbH, Darmstadt Faraday dish for making measurements at the beam paths of a _heavy ion accelerator
FR2550017A1 (fr) * 1983-07-27 1985-02-01 Varian Associates Charge calorimetrique a micro-ondes
US5025193A (en) * 1987-01-27 1991-06-18 Varian Associates, Inc. Beam collector with low electrical leakage
DE4211756A1 (de) * 1992-04-08 1993-10-14 Licentia Gmbh Elektronenstrahlröhre
DE4418649A1 (de) * 1993-06-03 1994-12-08 Eev Ltd Elektronenstrahlröhren
US6429589B2 (en) 1999-04-16 2002-08-06 Northrop Grumman Corporation Oil-cooled multi-staged depressed collector having channels and dual sleeves
US20030122491A1 (en) * 2002-01-03 2003-07-03 Ives R. Lawrence Depressed collector for electron beams
US6601641B1 (en) * 2000-03-31 2003-08-05 Thomcast Communications, Inc. Oil cooled multistage depressed collector high power amplifier
FR2854728A1 (fr) * 2003-05-06 2004-11-12 Thales Sa Tube hyperfrequence a faible rayonnement parasite
US20070215459A1 (en) * 2006-03-15 2007-09-20 Krzeminski Paul A Liquid cooling system for linear beam device electrodes

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2958804A (en) * 1958-05-19 1960-11-01 Eitel Mccullough Inc Electron beam tube and circuit
US3153743A (en) * 1960-09-20 1964-10-20 Siemens Ag Electron collector for travelling wave tubes and the like
US3368102A (en) * 1965-06-09 1968-02-06 Sperry Rand Corp Collector structure operating at a depressed potential for collecting a hollow electron beam
US3453482A (en) * 1966-12-22 1969-07-01 Varian Associates Efficient high power beam tube employing a fly-trap beam collector having a focus electrode structure at the mouth thereof
US3644778A (en) * 1969-10-23 1972-02-22 Gen Electric Reflex depressed collector

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1541078B2 (de) * 1966-07-08 1975-01-02 Telefunken Patentverwertungsgesellschaft Mbh, 7900 Ulm Elektronenstrahlröhre mit Auffängerelektrode
FR1533674A (fr) * 1967-08-04 1968-07-19 Siemens Ag Collecteur d'électrons pour tubes à faisceau électronique

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2958804A (en) * 1958-05-19 1960-11-01 Eitel Mccullough Inc Electron beam tube and circuit
US3153743A (en) * 1960-09-20 1964-10-20 Siemens Ag Electron collector for travelling wave tubes and the like
US3368102A (en) * 1965-06-09 1968-02-06 Sperry Rand Corp Collector structure operating at a depressed potential for collecting a hollow electron beam
US3453482A (en) * 1966-12-22 1969-07-01 Varian Associates Efficient high power beam tube employing a fly-trap beam collector having a focus electrode structure at the mouth thereof
US3644778A (en) * 1969-10-23 1972-02-22 Gen Electric Reflex depressed collector

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3925701A (en) * 1973-11-08 1975-12-09 Siemens Ag Electron beam collector electrode for an electron beam tube
US4179615A (en) * 1977-09-07 1979-12-18 Gesellschaft fur Schwerionenforschung mbH, Darmstadt Faraday dish for making measurements at the beam paths of a _heavy ion accelerator
FR2550017A1 (fr) * 1983-07-27 1985-02-01 Varian Associates Charge calorimetrique a micro-ondes
US5025193A (en) * 1987-01-27 1991-06-18 Varian Associates, Inc. Beam collector with low electrical leakage
DE4211756A1 (de) * 1992-04-08 1993-10-14 Licentia Gmbh Elektronenstrahlröhre
DE4418649A1 (de) * 1993-06-03 1994-12-08 Eev Ltd Elektronenstrahlröhren
US6429589B2 (en) 1999-04-16 2002-08-06 Northrop Grumman Corporation Oil-cooled multi-staged depressed collector having channels and dual sleeves
US6601641B1 (en) * 2000-03-31 2003-08-05 Thomcast Communications, Inc. Oil cooled multistage depressed collector high power amplifier
US20030122491A1 (en) * 2002-01-03 2003-07-03 Ives R. Lawrence Depressed collector for electron beams
US6838829B2 (en) * 2002-01-03 2005-01-04 Calabatas Creek Research, Inc. Depressed collector for electron beams
FR2854728A1 (fr) * 2003-05-06 2004-11-12 Thales Sa Tube hyperfrequence a faible rayonnement parasite
WO2004100204A3 (fr) * 2003-05-06 2008-07-03 Thales Sa Tube hyperfrequence a faible rayonnement parasite
US20070215459A1 (en) * 2006-03-15 2007-09-20 Krzeminski Paul A Liquid cooling system for linear beam device electrodes
US8872057B2 (en) 2006-03-15 2014-10-28 Communications & Power Industries Llc Liquid cooling system for linear beam device electrodes

Also Published As

Publication number Publication date
FR2197228B1 (enrdf_load_stackoverflow) 1978-09-08
IL42924A0 (en) 1973-11-28
FR2197228A1 (enrdf_load_stackoverflow) 1974-03-22
IL42924A (en) 1976-02-29
CA999332A (en) 1976-11-02
GB1389985A (en) 1975-04-09
JPS49134264A (enrdf_load_stackoverflow) 1974-12-24
DE2341503A1 (de) 1974-03-07
JPS5720656B2 (enrdf_load_stackoverflow) 1982-04-30

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