US3300735A - Phase shift beam tube neutralizer and modulator - Google Patents

Phase shift beam tube neutralizer and modulator Download PDF

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Publication number
US3300735A
US3300735A US248499A US24849962A US3300735A US 3300735 A US3300735 A US 3300735A US 248499 A US248499 A US 248499A US 24849962 A US24849962 A US 24849962A US 3300735 A US3300735 A US 3300735A
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United States
Prior art keywords
accelerating
cathode
anode
current
collector
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Expired - Lifetime
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US248499A
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English (en)
Inventor
George M W Badger
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.)
Varian Medical Systems Inc
Original Assignee
Varian Associates Inc
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Filing date
Publication date
Priority to GB1052220D priority Critical patent/GB1052220A/en
Application filed by Varian Associates Inc filed Critical Varian Associates Inc
Priority to US248499A priority patent/US3300735A/en
Priority to FR958920A priority patent/FR1379314A/fr
Application granted granted Critical
Publication of US3300735A publication Critical patent/US3300735A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H01J25/10—Klystrons, i.e. tubes having two or more resonators, without reflection of the electron stream, and in which the stream is modulated mainly by velocity in the zone of the input resonator

Definitions

  • This invention relates to a phase shift neutralizer and more particularly to apparatus for neutralizing phase shlft due to velocity variation in the beam of a beam type tube such as a klystron.
  • a modulating anode type beam tube there is generally provided a source of electrons, a modulating anode which controls the beam density, an accelerating anode which controls the velocity of the beam, and a radio frequency section which interacts with the beam to form the output signal.
  • a modulating anode which controls the beam density
  • an accelerating anode which controls the velocity of the beam
  • a radio frequency section which interacts with the beam to form the output signal.
  • an accelerating anode in tubes which employ a grid structure for controlling the beam density
  • the side effect is to also provide a variation in beam velocity.
  • the variation in beam velocity affects the phase of the output of the radio frequency section associated with the beam. Between the minimum current density and the maximum current density, there may be a considerable phase shift which, of course, distorts the output pulse or signal.
  • a modulated beam type beam tube such as a klystron including a modulating anode or other modulating electrode.
  • FIGURE 1 is a schematic diagram of a beam projection and interception means with one feedback circuit
  • FIGURE 2 is a schematic diagram of a beam projection and interception means with another feedback circuit.
  • an electron gun 11 for a beam type tube there is shown an electron gun 11 for a beam type tube.
  • the gun includes a cathode 13 heated by a filament 15 and situated within a focusing electrode 17.
  • the cathode 13 and focusing electrode 17 are connected to the cathode terminal 19.
  • Disposed in front of the cathode 13 is a modulating anode 21 and an accelerating anode 23.
  • Radio frequency structures may be disposed to interact with the beam, for example, in a klystron.
  • Various resonators and cavities are disposed along the beam.
  • a radio frequency structure is not shown in the drawing since it is not deemed to importance to the instant invention.
  • a collector 25 is shown at the opposite end of the 'klyst-ron unit in axial alignment with the cathode 13 and the anodes 21 and 23. The collector interrupts and collects the beam.
  • An inductor 27 is connected to the cathode terminal 19 and the opposite end of the inductor is coupled through the parallel connected capacitor 29 and power supply 31 to the accelerating anode 23. Also connected between the inductor 27 and the anode 23 is a pair of series switching tubes 33 and 35. The junction of the anode of tube 33 and cathode of tube 35 is connected to the modulating anode 21. Modulating voltages may be applied to the grids of the tubes 3-3 and 35 in conventional manner to modulate the beam current.
  • a capacitor 37 and a resistor 39 are serially connected between the cathode terminal 19 and the anode 23.
  • the junction of the capacitor 37 and the resistor 39 is connected to a source of positive voltage B+ through vacuum tube 41.
  • the grid is controlled by a voltage applied through transformer 43, the secondary of which is connected between the grid and cathode of tube 41.
  • the primary of the transformer is connected between the positive terminal of the power supply 31 and the collector 25. It will be apparent to one skilled in the art that a solid state device may be substituted for the tube 41.
  • the electron beam 45 In normal operation of the beam-type device similar to that shown (but ignoring the inductor 27, capacitor 37, resistor 39, tube 41 and transformer 43), the electron beam 45, as it passes through the anodes 21 and 23, includes a substantial negative charge to the electrons within the beam itself.
  • modulating voltage is applied by the modulating anode 21 to vary the beam current, the beam acceleration due to the fields from the accelerating anode changes.
  • the electrons near the outer perimeter of the beam 45 are affected by the accelerating voltages to a greater degree than those electrons near the center of the beam which are relatively isolated from the accelerating voltage.
  • phase shift in the output of the radio frequency section is caused by the change in beam velocity
  • the phase shift is proportional to the beam density.
  • the beam density may be easily detected at the collector 25 and, in accordance with this invention, is used as a feedback signal to neutralize the phase shift.
  • the beam density is controlled by controlling the degree of conduction of each of the tubes 33 and 35.
  • a feedback signal is derived which serves to increase the accelerating voltage as the beam density increases whereby to maintain substantially constant beam velocity with changing beam current.
  • the feedback circuit previously described, includes the collector 25 connected to the primary of a transformer 43 whereby the beam current passes through the primary and induces a voltage between the grid and cathode of the tube 41 which is proportional to the current to thereby control the conduction of the tube 41.
  • the current for the tube is supplied through the inductor 27.
  • the voltage drop across the induct-or 27 changes and adds to or subtracts from the accelerating voltage.
  • the transformer 43 is phased so that the tube 41 conducts less current as the beam current increases to thereby reduce the voltage drop in the inductor and increase the accelerating voltage.
  • the means for deriving the feedback signal again comprises a transformer.
  • the transformer 51 which has its primary serially connected between the positive terminal of the power supply and the positive terminal of an auxiliary power supply or battery 52 which, in turn, has its negative terminal connected to the collector thereby provide a depressed collector connection.
  • the secondary of the transformer has one terminal connected to the positive terminal of the power supply and its other terminal connected to the cathode lead through a capacitor 54.
  • Operation of the circuit is to circulate a current dependent on beam current in the loop including the power supply '31, secondary of transformer 51, capacitor 54 and inductor 27.
  • the circulating current increases and decreases as the beam current increases and decreases and, in turn, the accelerating voltage is controlled to maintain a constant average beam velocity.
  • a circuit for eliminating phase shift due to velocity variation arising from variations in beam density in a beam tube having an accelerating means, a cathode and a collector, means for applying an accelerating voltage to said accelerating means, and feedback means responsive to the intensity of said beam connected between said collector and said accelerating means for varying said accelerating voltage in direct proportion to the said variations in beam density.
  • an electron beam type tube of the type which includes a cathode, an accelerating anode for accelerating electrons leaving the cathode, a beam current modulating electrode for modulating the beam current, and a collector for intercepting the beam, means for applying an accelerating voltage between the cathode and anode, means for applying a modulating voltage between said cathode and said modulating electrode, and means responsive to the collector current for varying the accelerating voltage between the cathode and anode in direct proportion to the beam current to neutralize velocity variations in the beam due to variations in beam current.
  • a circuit for minimizing phase shift due to velocity variation arising from variations in beam density in'a beam tube including a cathode and a collector between which an electron beam is projected, accelerating means for controlling the beam velocity, means for applying an accelerating voltage to said accelerating means, and feedback means responsive to the density of said beam connected between said collector and said accelerating means for varying the accelerating voltage applied to said accelerating means in direct proportion to said variations in beam density.
  • an electron beam type tube of the type which includes a cathode, an accelerating anode for accelerating electrons leaving the cathode, a beam current modulating means for modulating the beam current, and a collector for intercepting the beam, means for applying an accelerating voltage between the cathode and anode, and means responsive to the collector current for varying the accelerating voltage between the cathode and anode in direct proportion to said beam current to neutralize velocity variations in the beam due to variations in beam current density.
  • a circuit for minimizing phase shift due to velocity variations arising from beam density variations in a beam tube including a cathode and a collector between which an electron beam is projected, accelerating means for controlling the beam velocity, means for applying an accelerating voltage to the accelerating means, and feedback means including the primary windings of a transformer connected in the collector current path, and means associated with the secondary windings of said transformer for varying the voltage applied to said accelerating anode.
  • said means associated with the secondary winding of the transformer comprises an inductor connected in series with said means for applying an accelerating voltage to said accelerating means, and means for causing current to flow in said inductor in response to changes in beam current.
  • An electron beam type tube including a cathode, an accelerating anode for accelerating electrons leaving the cathode, a modulating anode disposed in the electron path between the cathode and accelerating anode, means for controlling the voltage on the modulating anode to modulate the beam current, a collector spaced from the accelerating anode and serving to collect the electrons, means for applying an accelerating voltage between the cathode and accelerating anode, and means responsive to the collector current for varying the accelerating voltage in direct proportion to said beam current to neutralize velocity variations in the beam due to variations in beam density.

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US248499A 1962-12-31 1962-12-31 Phase shift beam tube neutralizer and modulator Expired - Lifetime US3300735A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
GB1052220D GB1052220A (enrdf_load_stackoverflow) 1962-12-31
US248499A US3300735A (en) 1962-12-31 1962-12-31 Phase shift beam tube neutralizer and modulator
FR958920A FR1379314A (fr) 1962-12-31 1963-12-30 Dispositif de neutralisation du déphasage dans les tubes à faisceau électronique tels que les klystrons

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US248499A US3300735A (en) 1962-12-31 1962-12-31 Phase shift beam tube neutralizer and modulator

Publications (1)

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US3300735A true US3300735A (en) 1967-01-24

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GB (1) GB1052220A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3505612A (en) * 1967-06-29 1970-04-07 Raytheon Co Noise power generator utilizing secondary emission sources energized by radio frequency means
US3760285A (en) * 1972-07-11 1973-09-18 Westinghouse Electric Corp High speed pulser
US3806836A (en) * 1972-01-10 1974-04-23 R Alsmeyer Simplified floating deck pulse modulator
US4642518A (en) * 1984-03-23 1987-02-10 Sciaky S.A. Installation of electron beam metalworking
US5175468A (en) * 1990-11-30 1992-12-29 Proel Technologie S.P.A. Device for generating an on-off modulation electron beam

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2229700A (en) * 1937-06-09 1941-01-28 Radio Patents Corp Selective space discharge device
US2808470A (en) * 1954-05-18 1957-10-01 Rca Corp Electron discharge device structures and circuitry therefor
US3108232A (en) * 1960-07-06 1963-10-22 Gen Telephone & Elect Ultra high frequency amplifier

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2229700A (en) * 1937-06-09 1941-01-28 Radio Patents Corp Selective space discharge device
US2808470A (en) * 1954-05-18 1957-10-01 Rca Corp Electron discharge device structures and circuitry therefor
US3108232A (en) * 1960-07-06 1963-10-22 Gen Telephone & Elect Ultra high frequency amplifier

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3505612A (en) * 1967-06-29 1970-04-07 Raytheon Co Noise power generator utilizing secondary emission sources energized by radio frequency means
US3806836A (en) * 1972-01-10 1974-04-23 R Alsmeyer Simplified floating deck pulse modulator
US3760285A (en) * 1972-07-11 1973-09-18 Westinghouse Electric Corp High speed pulser
US4642518A (en) * 1984-03-23 1987-02-10 Sciaky S.A. Installation of electron beam metalworking
US5175468A (en) * 1990-11-30 1992-12-29 Proel Technologie S.P.A. Device for generating an on-off modulation electron beam

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GB1052220A (enrdf_load_stackoverflow)

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