US2774869A - Electron discharge apparatus - Google Patents

Electron discharge apparatus Download PDF

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Publication number
US2774869A
US2774869A US194540A US19454050A US2774869A US 2774869 A US2774869 A US 2774869A US 194540 A US194540 A US 194540A US 19454050 A US19454050 A US 19454050A US 2774869 A US2774869 A US 2774869A
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Prior art keywords
helix
source
frequency
cathode
wave
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US194540A
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English (en)
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Burke Peter Francis Conway
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International Standard Electric Corp
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International Standard Electric Corp
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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
    • H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps
    • H01J25/36—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field
    • H01J25/38—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field the forward travelling wave being utilised
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B43/00—Preparation of azo dyes from other azo compounds
    • C09B43/12—Preparation of azo dyes from other azo compounds by acylation of amino groups
    • C09B43/136—Preparation of azo dyes from other azo compounds by acylation of amino groups with polyfunctional acylating agents
    • C09B43/14—Preparation of azo dyes from other azo compounds by acylation of amino groups with polyfunctional acylating agents with phosgene or thiophosgene
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B43/00—Preparation of azo dyes from other azo compounds
    • C09B43/12—Preparation of azo dyes from other azo compounds by acylation of amino groups
    • C09B43/136—Preparation of azo dyes from other azo compounds by acylation of amino groups with polyfunctional acylating agents
    • C09B43/16—Preparation of azo dyes from other azo compounds by acylation of amino groups with polyfunctional acylating agents linking amino-azo or cyanuric acid residues

Definitions

  • the present invention relates to frequency multiplier apparatus for use at decimeter and centimeter wavelengths, especially where a largebandwidth is required.
  • Such apparatus sufiers from the defect that, due to the necessarily sharp tuning of the cavity resonators, a fundamental carrier wave which is amplitude or frequency modulated 'over "a wide band cannot conveniently be employed.
  • apparatus such as the Kompfner travelling wave tube is capable of giving amplification over a very wide band.
  • a slow-waveguide structure such as a helix, is made to provide a component of the input signal travellingat a velocity near that of a beam of electrons which may be caused to travel along the same path as the said slow component.
  • Such slow-Wave structures may be made dispersive so that the velocity of the slow wave varies with frequency.
  • the present invention uses apparatus in which a density modulated beam of electrons is introduced into travelling wave apparatus so dimensioned as to be sufficiently dispersive to discriminate between one particular harmonic and the others, including the fundamntal, but which, nevertheless, has a considerable bandwidth in the neighbourhood 0f the desired harmonic.
  • This desired harmonic will be that for which the slow-wave velocity is the same as the beam velocity and continued interaction between the density modulated beam and the slow-wave structure.
  • electron discharge apparatus comprising an electromagnetic waveguide adapted to propagate waves of a given frequency with a phase velocity a fraction that of light, means for projecting a beam of electrons along the said guide to progressively amplify waves of the said frequency, the dispersion of the Waveguide being such that the amplification is selective for that frequency with respect to sub-multiples and multiples thereof, and means for modulating the charge density along the beam at a sub-multiple of the given frequency in a region prior to the entrance of the beam into the said guide.
  • the means for modulating the charge density along the beam may take various forms, for example, another travelling wave structure may be used or a launcher resonator, as in a klystron, or, as is preferred, a cathodegrid structure, partof the electron gun, may be used as 2,774,869 Patented Dec. 18, 1956 in a class C amplifier or oscillator.
  • the travelling wave structure used in apparatus according to the present invention must be dispersive and, in general, special types of electron discharge device are required for use with the invention.
  • the invention also provides, therefore, an electron discharge device comprising an electron gun adapted to project a beam of electrons along the axis of a helix of conducting material dimensioned to propagate axial waves of "a given frequency with a phase velocity a fraction that of light, the propagation constant of the said waves and the mean radius a of the helix being such that the product a lies between 0.6 and 1.4, the said electron gun having a cathode and a control grid which, together with a beam accelerating electrode, would form, were the said accelerating electrode non-permeable to electrons, a triode amplifier valve suitable for use in a class C amplifier at a su'b multiple of the said given frequency, the said submultiple being the driving frequency it is desired to multiply.
  • Fig. l is a diagrammatic representation, in part section of an electron discharge device connected in circuit according to the present invention.
  • Fig. 2 shows a modification of the apparatus of Pig. 1 using a cavity resonator as a buncher
  • Fig. 3 shows an embodiment using a further travelling w-ave structure for bunching
  • Fig. 4 shows, in part sectional elevation a further embodiment of the invention.
  • Fig. 5 shows a plan view of part of the construction of Fig. 4.
  • reference numeral 1 indicates an electron discharge device of the Kompfner travelling wave type, having a conventional helix 2 and collector electrode 3, surrounded by magnetic beam concentrating coils 4 and 5.
  • a conventional type of waveguide output 6, together with an adjustable matching section 7, is connected to the havelling-wave tube in known manner. however, differs considerably from that conventionally used and consists of a cathode 8 and grid 9 similar to those in a U. H. F. triode.
  • An accelerating anode 10 annular in shape so as not to intercept any of the beam, takes the place of the ordinary anode in the triode.
  • Grid and cathode electrodes are brought out coaxially as indicated at -11 and 1-2 respectively, the resulting transmission line being tuned by the annular piston 13, and
  • the input is applied through the coaxial connection 14 from a source 15.
  • a helix can provide sufiicient discrimination to extract the third harmonic of an exciting fundamental.
  • the product a for the helix 2 should lie between 0.6 and 1.4. Low values of 7 lead to a greater discrimination between har- 'monics but a smaller bandwidth, so the value chosen.
  • the electron gun The electron gun
  • the member 11 connected to the control grid 8 of the electron gun may conveniently be earthed, as indicatedin the drawing, while the member 12 is connected through a cathode resistance 16 to the negative pole of potential source 17.
  • a bias potential source 18 is shown connected between the grid member 11 and the junction of resistance 16 and source 17.
  • the positive pole of source 17 is shown connected to the collector electrode 3 and a current source for heating the cathode 8' is connected at 19 to heater leads 20 brought out coaxially with the cathode conductor 12.
  • the cathode, control grid and accelerating anode of the electron gun are arranged so that were a member non-permeable to electrons to replace the accelerating anode 10, the structure would form a triode suitable for use as a class C amplifier at the frequency of the driving source
  • the high frequency op'eratioi'r differs somewhat from that of the ordinary class C triode in the following manner.
  • the effect of transit time on the operation of the cathode-grid structure at high frequencies will be to shorten the angular duration of the current pulse passing the grid for a given angle of flow at the cathode. Since the anode is at a constant voltage, there will be no subsequent lengthening of the current pulse as happens in the class C operated triode at high frequencies.
  • the radio frequency power needed to drive the grid will increase, since the electrons emitted While the grid is positive, but which are later returned to the cathode because they have not passed the grid before it becomes negative, will absorb power without contributing to the current of the beam.
  • the drive power required for a particular angle of flow and average current is to be kept as small as possible, it is necessary that the transit angle of electrons from cathode to grid be small and that the transco'nductance be high. Both of these are achieved by bringing the grid as near the cathode as is mechanically possible, so that a spacing of about 0.005" is required for tubes driven with frequencies in the decirnet'er wavelength range.
  • the distance from the grid to the accelerating electrode is determined partly by the need to keep the positive grid characteristics good, i. e. to reduce the current intercepted by the grid when it is positive.
  • the amplification factor chosen (which determines the pitch of the helix Winding) depends 'on the current desired at zero bias, the amount of negative bias required when operating under class C conditions and such factors.
  • Fig. 2 of the accompanying drawings the class C triode electron gun of Fig. 1 is replaced by a cavity resonator 22 and an ordinary type of electron gun 23.
  • the resonator may conveniently be constructed as a pair of discs 24 sealed through the glass envelope 25 of the discharge device and clamped between metal rings 26, 27 and 28.
  • the body of the resonator is connected to ground and a potential source 29 is connected between ground and the collector electrode 3.
  • the helix is preferably polarised through separate connections'no't-s'ho'wn.
  • a magnetic focussing coil 30 serves to focus the'beam from the electron gun through the resonator 22 and is supplied with current from D. C. potential source 31'.
  • the cathode of gun 23 is held at a negative potential with respect to ground by means of D. C. potential source 32. If desired, in order that the electron beam may be well bunched before entering the helix 2, a drift tube 33 may be inserted as shown between the helix 2 and resonator 22, the drift tube being connected to the end of the helix. 7 V
  • a further travelling wave structure as shown in Fig. 3 may be employed.
  • This embodiment comprises a helix 34 provided with conventional input and output arrangements, as indicated by the wave guides 35 and 36 respectively, wave guide 6 including a matching terminal indicated at 7.
  • the modulating means may be arranged as an oscillator oscillating at the required subharmonic frequency.
  • the source 15 and terminating arrangements 37 may be omitted and a feedback coupling provided by the waveguide 44, indicated by the dotted lines, a cavity resonator 45 being included in the feedback path if desired.
  • a resonant structure 46' functioning in the manner of a known coaxial line type of velocity modulation oscillator, is employed.
  • the resonant structure shown comprises end discs 47 and 48 sealed respectively to envelope portions 49, surrounding the electron gun 23, and portion 50, surrounding the helix 2.
  • a cylindrical metal wall 51 joins the two end discs 47 and 48.
  • a central conductor 52 extends diametrically across the cylindrical member 51 and is apertured to permit passage of the electron beam.
  • Pins 53, 54 and 55 are shown connected to the end discs47, 48 and to the central conductor 52, respectively, to define interaction gaps within the resonator, the passage through the conductor 52 forming a drift space between them.
  • a focussing coil 56 is shown surrounding the helix and oscillator portions'of the tube.
  • a helix is used for the dispersive waveguide
  • applications of the invention are not limited to this.
  • Other forms of slowvelocity dispersive waveguides such as two helices, one inside the other, a waveguide or coaxial line inductively loaded with slots or one in which the slots are detuned to give a flat phase velocity/frequency characteristic over a wide band with good rejection outside that band could also be used.
  • Electron discharge apparatus comprising an electromagnetic waveguide in the form of a helical conductor, for propagating waves of a given frequency with a phase velocity a fraction that of light, the mean radius a of the helix and the propagation constant 'y' of the waves being such that the product 7a" liesb'etween 0.6 and 1.4, an electron beam source positioned to project a beam of electrons alongthe said guide to progressively amplify waves of the said frequency, the dispersion of the waveguide being such that the amplification is selective for that frequency with respect to sub-multiples and multiples thereof, a source of waves of a submultiple frequency of said given frequency positioned intermediate said beam source and said guide and means for modulating the charge density along the beam with energy from said wave source.
  • Electron discharge apparatus comprising an electromagnetic waveguide in the form of a helical conductor for propagating waves of a given frequency with a phase velocity a fraction that of light, the mean radius a of the helix and the propagation constant 7 of the waves being such that the product 'ya lies between 0.6 and 1.4, an electron beam source positioned to project a beam of electrons along the said guide to progressively amplify waves of the said frequency, the dispersion of the waveguide being such that the amplification is selective for that frequency with respect to sub-multiples and multiples thereof, a source of waves of a submultiple frequency of said given frequency positioned intermediate said beam source and said guide, and means for modulating the charge density along the beam with energy from said wave source, said beam source comprising an electron gun having a cathode and a control grid, said means for modulating comprising a transmission line surrounding said cathode and control grid and coupling said wave source between said cathode and control grid, and means for biasing said grid to project said beam
  • Electron discharge apparatus comprising an electromagnetic wave guide in the form of a helical conductor for propagating waves, an electron beam source positioned to project a beam of electrons along said guide to progressively amplify said waves, a source of waves positioned intermediate said beam source and said guide, and means for modulating the charge density along the beam with energy from said Wave source, said beam source comprising an electron gun having a cathode and a control grid, said means for modulating comprising a transmission line surrounding said cathode and control grid and coupling said wave source between said cathode and control grid.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Coloring (AREA)
  • Microwave Tubes (AREA)
  • Particle Accelerators (AREA)
US194540A 1949-11-08 1950-11-07 Electron discharge apparatus Expired - Lifetime US2774869A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB303049X 1949-11-08
GB2774869X 1949-11-08

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US2774869A true US2774869A (en) 1956-12-18

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US (1) US2774869A (de)
CH (2) CH302049A (de)
GB (1) GB671296A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2981889A (en) * 1956-10-18 1961-04-25 Gen Electric Electron tube frequency multiplier of the traveling wave type

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2753481A (en) * 1952-06-14 1956-07-03 Sperry Rand Corp Travelling wave oscillators

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2233779A (en) * 1935-11-30 1941-03-04 Telefunken Gmbh Electron discharge device
US2300052A (en) * 1940-05-04 1942-10-27 Rca Corp Electron discharge device system
US2516944A (en) * 1947-12-18 1950-08-01 Philco Corp Impedance-matching device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2233779A (en) * 1935-11-30 1941-03-04 Telefunken Gmbh Electron discharge device
US2300052A (en) * 1940-05-04 1942-10-27 Rca Corp Electron discharge device system
US2516944A (en) * 1947-12-18 1950-08-01 Philco Corp Impedance-matching device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2981889A (en) * 1956-10-18 1961-04-25 Gen Electric Electron tube frequency multiplier of the traveling wave type

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Publication number Publication date
CH298139A (de) 1954-04-30
CH302049A (de) 1954-09-30
GB671296A (en) 1952-04-30

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