US2417551A - Electron discharge device and associated circuit - Google Patents

Electron discharge device and associated circuit Download PDF

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US2417551A
US2417551A US485290A US48529043A US2417551A US 2417551 A US2417551 A US 2417551A US 485290 A US485290 A US 485290A US 48529043 A US48529043 A US 48529043A US 2417551 A US2417551 A US 2417551A
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electrode
resonator
potential
reflecting
electrons
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US485290A
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Hill Stanley
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EMI Ltd
Electrical and Musical Industries Ltd
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EMI Ltd
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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
    • H01J25/22—Reflex klystrons, i.e. tubes having one or more resonators, with a single reflection of the electron stream, and in which the stream is modulated mainly by velocity in the modulator zone
    • H01J25/24—Reflex klystrons, i.e. tubes having one or more resonators, with a single reflection of the electron stream, and in which the stream is modulated mainly by velocity in the modulator zone in which the electron stream is in the axis of the resonator or resonators and is pencil-like before reflection

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  • This invention relates to electron discharge de- '5 further electrode between vices of the velocity-modulation type employing hollow resonators and in which a stream of electrons after having been velocity-modulated by passing through the resonator gap is adapted to be 3 Claims.
  • the efflciency of devices of the kind referred to can'be substantially improved by arranging that the field gradient in the space between the resonator and the reflecting electrode has a positive or zero value over at least half the distance between the middle of the gap in the resonator andthe zero equi-potential surface which is setup in operation between the resonator and the reflecting electrode.
  • the field gradient has the positive and negative values referred to herein when said values are derived from a plot of thepotential distribution taken from the resonator to the refleeting electrode.
  • I provide an electron discharge device and a circuit of the type referred to wherein the construction and arrangement of the electrodes are such that with suitable potentials applied to the electrodes the field gradient along the path of theelectrons between the resonator and the reflecting electrode has a positive or zero value over at least half the distance between the middle of the gap in the resonator and the zero equi potential surfacewhich is set up in the space between the resonator and the reflecting electrode.
  • a field gradient can be obtainedin a variety of ways, such as by shaping the reflecting electhe resonator and the reflectingelectrode.
  • the shape of the further electrode will depend onthe form of the electron beamand in cases where the electron beamis of asubstantially'circular'forin in cross-section, the further electrode may-comprise a cylinder-or disc surrounding the beam.
  • Other forms of refiectingelectrodescan beemployeddepending on the shape of the electronbeam as will hereinafter be referred to.
  • a potential distribution between "the resonator and the "reflecting-electrode which passesfrom a positive value atthe-resonator- -linearly with distance through zero-to a negative-value at the reflecting electrode provides a constant potential gradient'throughout thespa'ce and hence the field gradient is always'zero.
  • a zero field gradient can be approximated in practice by providing a large number of further electrodesbetween the resonator'and the reflecting electrodathe further electrodes being maintained at slightly different potentials passingfrom a positive value at the further electrode closest to the resonator to a negative value at the further electrode-closest to the reflectingtelectrode, the potentials applied to the further electrodesbeing so chosen that the potential distribution .is substantially linear.
  • Such an arrangement is, however, .cumbersomein practice and hence; for practical purposes, it is preferred toiemploy aeminimum number of further electrodes.
  • the drawingwthe reference numeral I indicatesthe evacuated envelope of the device having at one-ends.
  • cathode 2 whichis arrangedto project azbeam of electronsthrough the gap 3 in a hollowresonator flythe electron stream passing through the resonator being directed towards a reflecting electrode -51
  • Thehollowres'on'ator 4 is of toroidal formhaving the cross-section shown and is arranged partly within and p'artly outside the evacuated "envelope 1.
  • a further electrode 6 is provided arranged between the resonator 4 and the electrode 5.
  • a low current of about 10 to milliamperes is employed and the resonator 4 is maintained at a high potential of about 1000 to 2000 volts positive with respect to the cathode 2 and the reflecting electrode 5 at a potential of 100-200 volts negative with respect to the cathode the further electrode 6 being maintained at a potential, preferably at a negative potential, intermediate the potentials applied to the resonator l and the reflecting electrode 5.
  • the field gradient is changed by introduction of the electrode 6 which sets up between the resonator 4 and the reflecting electrode 5 equi-potential surfaces which are ,concave facing the resonator '4, as indicated by the dotted lines, these concave equi-potential surfaces extending over a distance along the path of the electrons which is longer than the distance over which concave surfaces would be set up in the absence of the further electrode 6, so that the field gradient has a positive value over at least half the distance along the path of the electrons between the middle of the gap 3 in the resonator and the zero equi-potential surface which is set up between the resonator and reflecting electrode.
  • the zero equi-potential surface referred to herein is the equi-potential surface having the potential of the cathode of the device.
  • the resonator may be maintained at earth potential and the cathode at about 1000 volts negative with respect to earth and the reflecting electrode at about 1100 or 1200 volts negative with respect to earth.
  • the zero equi-potential surface between the resonator and reflecting electrode will be the 1000 volts negative equi-potential with respect to earth.
  • the wall of the resonator adjacent the reflecting electrode is symmetrical with the wall adjacent the cathode and such a construction of resonator is also found to impair the efficiency of operation owing to the re-entrant form of the rear wall. It will be observed that in the construction shown in the drawing the rear wall of the resonator is substantially flat in the vicinity of the reflecting electrode and this flattening of the rear wall of the resonator is also found to effect an improvement on the (efficiency of operation.
  • the reflecting electrode 5 in the example shown is substantially flat although, in some cases, the reflecting electrode 5 may be of concave form with the concavity facing the resonator.
  • the electrode 6 may comprise a cylinder, about 6 millimetres in diameter and the length of the cylinder may be about 3 millimetres.
  • the distance between the rear wall of the resonator and the reflecting electrode may be about 5 or 6 millimetres.
  • the diameter of the apertures forming the gap in the resonator 4 may be about 3 or 4 millimetres in diameter.
  • the device shown is intended to be employed with an electron beam of a substantially circular form in cross section and in this case the further electrode 6 will also preferably be of circular form in cross section.
  • the further electrode 6 will also preferably be of circular form in cross section.
  • one or more apertured diaphragms may be employed, these apertured diaphragms also serving to provide the required field gradients and by employing more than one apertured diaphragm or more than one of the cylindrical electrodes, shorter in length than that mentioned above, and maintaining these electrodes at potentials which are progressively more negative towards the reflecting electrode 5, the distance along the path of the electrons over which the concave equi-potential surfaces are set up can be increased, and the field gradient can be caused to approach closer to the zero field gradient referred to above.
  • the further electrode 6 will be shaped appropriately and may comprise a cylinder having an elongated cross-section or a diaphragm having an elongated opening or, alternatively, may comprise a pair of flat strips lying substantially parallel to the major axis of the ribbon-shaped beam as viewed in cross section. The pair of strips will be maintained at the same potential.
  • the features of the invention can also be applied to electron discharge devices where an electron stream flows radially through an annular gap in a resonator.
  • the further electrode may comprise a pair of rings lying one on each side of the beam.
  • a high frequency apparatus including a source of electrons and an electrode toward which said electrons are to be directed, and a cavity resonator positioned between said source of electrons and said electrode, electrode means between said resonator and said electrode, means including a source of voltage and conductors connected between said source of voltage and said resonator, said electrode and said electrode means for maintaining said resonator at a high positive potential with respect to said cathode, said electrode at a negative potential with respect to said cathode, and said electrode means at a potential intermediate that of the resonator and said electrode.
  • a high frequency apparatus including a source of electrons and an electrode toward which said electrons are to be directed, and a cavity resonator positioned between said source of electrons and said electrode, electrode means between said resonator and said electrode, said electrode means comprising a tubular ring-like member closely surrounding the electron path and spaced closely adjacent said resonator and said electrode, means including a source of voltage and conductors connected between said source of voltage and said resonator, electrode and electrode means for maintaining said resonator at a high positive potential with respect to said cathode, and said electrode at a negative potential with respect to said cathode, and said electrode means at a potential intermediate that of the resonator and said electrode.
  • a high frequency apparatus includin an electron discharge device having a source of electrons and an electrode toward which said electrons are to be directed, a cavity resonator positioned between said cathode and said electrode and through which electrons are directed during operation of said apparatus, and only a single tubular electrode means positioned between said resonator and said electrode and through which the path of the electrons extends between said resonator and said electrode and closely sur- ,5 rounding said path, said resonator having a flat surface adjacent said tubular electrode means and transverse to the path of the electrons, and a voltage source having conductors connected between said voltage source, said resonator, electrode and electrode means for applying a positive potential to said resonator and a negative potential to said electrode with respect to said cathode, and a potential intermediate said two potentials to said tubular electrode means, whereby the field gradient along the path of the electrons between the resonator and the electrode has a value other than negative at least half the distance between the middle of the gap in the reson

Description

s. HiLL March 18; 1947.
ELECTROf I nlscnmes DEVICE AND ASSOCIATED CIRCUIT File d May 1, 1945 0v VEA/TOP ab A-rrop/vEy Patented Mar. 18;, 1947 ELECTRON DISC trance DEVICE AND ASSQCIATEDGIECUIT Stanley Hill, HestonfEngland, assignor to Electric & Musical Industries Limited, Hayes, Middlesex,
England, a company of Great Btita'in- Application May 1, 1943, Serial No. 485,2 90 In Great Britain January 17, 1941 This invention relates to electron discharge de- '5 further electrode between vices of the velocity-modulation type employing hollow resonators and in which a stream of electrons after having been velocity-modulated by passing through the resonator gap is adapted to be 3 Claims. (Cl. 31 5 -5) reflected by the provision of a reflecting electrode It is found, however, that the efficiency of a device of this type when operating as a generator of oscillation is rather low when operating with a low current and a high resonator potential and this is to some extent due to the unsuitable poten- I, tial distribution of somewhat parabolic form in the space between the resonator and the reflecting electrode whereby only a small degree of bunching occurs. I have found that the efflciency of devices of the kind referred to can'be substantially improved by arranging that the field gradient in the space between the resonator and the reflecting electrode has a positive or zero value over at least half the distance between the middle of the gap in the resonator andthe zero equi-potential surface which is setup in operation between the resonator and the reflecting electrode. The field gradient has the positive and negative values referred to herein when said values are derived from a plot of thepotential distribution taken from the resonator to the refleeting electrode. i
According, therefore, to one feature of the invention I provide an electron discharge device and a circuit of the type referred to wherein the construction and arrangement of the electrodes are such that with suitable potentials applied to the electrodes the field gradient along the path of theelectrons between the resonator and the reflecting electrode has a positive or zero value over at least half the distance between the middle of the gap in the resonator and the zero equi potential surfacewhich is set up in the space between the resonator and the reflecting electrode. Such a field gradient can be obtainedin a variety of ways, such as by shaping the reflecting electhe resonator and the reflectingelectrode.
' The shape of the further electrode will depend onthe form of the electron beamand in cases where the electron beamis of asubstantially'circular'forin in cross-section, the further electrode may-comprise a cylinder-or disc surrounding the beam. Other forms of refiectingelectrodescan beemployeddepending on the shape of the electronbeam as will hereinafter be referred to. A potential distribution between "the resonator and the "reflecting-electrode which passesfrom a positive value atthe-resonator- -linearly with distance through zero-to a negative-value at the reflecting electrode provides a constant potential gradient'throughout thespa'ce and hence the field gradient is always'zero. Sucha new gradient aflords" a muchbetter result than is the case if the-fieldg-radientis positive. A zero field gradient can be approximated in practice by providing a large number of further electrodesbetween the resonator'and the reflecting electrodathe further electrodes being maintained at slightly different potentials passingfrom a positive value at the further electrode closest to the resonator to a negative value at the further electrode-closest to the reflectingtelectrode, the potentials applied to the further electrodesbeing so chosen that the potential distribution .is substantially linear. Such an arrangement is, however, .cumbersomein practice and hence; for practical purposes, it is preferred toiemploy aeminimum number of further electrodes.
In order that the said invention may be clearly understood andreadily carried into effect,sit will now be more :fully described with reference to the accompanying drawing which illustrates one form of discharge device provided with a further electro'de in accordance with, theinvention:
As shownin the drawingwthe reference numeral I indicatesthe evacuated envelope of the device having at one-ends. cathode 2 'whichis arrangedto project azbeam of electronsthrough the gap 3 in a hollowresonator flythe electron stream passing through the resonator being directed towards a reflecting electrode -51 Thehollowres'on'ator 4 is of toroidal formhaving the cross-section shown and is arranged partly within and p'artly outside the evacuated "envelope 1. 'In accordance with one'feature of the invention a further electrode 6 is provided arranged between the resonator 4 and the electrode 5. When operating the device shown in the drawing as a generator of self-maintained oscillations, a low current of about 10 to milliamperes is employed and the resonator 4 is maintained at a high potential of about 1000 to 2000 volts positive with respect to the cathode 2 and the reflecting electrode 5 at a potential of 100-200 volts negative with respect to the cathode the further electrode 6 being maintained at a potential, preferably at a negative potential, intermediate the potentials applied to the resonator l and the reflecting electrode 5. The field gradient is changed by introduction of the electrode 6 which sets up between the resonator 4 and the reflecting electrode 5 equi-potential surfaces which are ,concave facing the resonator '4, as indicated by the dotted lines, these concave equi-potential surfaces extending over a distance along the path of the electrons which is longer than the distance over which concave surfaces would be set up in the absence of the further electrode 6, so that the field gradient has a positive value over at least half the distance along the path of the electrons between the middle of the gap 3 in the resonator and the zero equi-potential surface which is set up between the resonator and reflecting electrode. The zero equi-potential surface referred to herein is the equi-potential surface having the potential of the cathode of the device. In practice, the resonator may be maintained at earth potential and the cathode at about 1000 volts negative with respect to earth and the reflecting electrode at about 1100 or 1200 volts negative with respect to earth. In this case the zero equi-potential surface between the resonator and reflecting electrode will be the 1000 volts negative equi-potential with respect to earth. In some of the previously proposed resonators the wall of the resonator adjacent the reflecting electrode is symmetrical with the wall adjacent the cathode and such a construction of resonator is also found to impair the efficiency of operation owing to the re-entrant form of the rear wall. It will be observed that in the construction shown in the drawing the rear wall of the resonator is substantially flat in the vicinity of the reflecting electrode and this flattening of the rear wall of the resonator is also found to effect an improvement on the (efficiency of operation.
The reflecting electrode 5 in the example shown is substantially flat although, in some cases, the reflecting electrode 5 may be of concave form with the concavity facing the resonator.
The disposition of the electrode 6 in relation to the resonator 4 and reflecting electrode 5 and the dimensions of the electrode 6 are not critical and in one form of the invention, given purely by way of example, ina case where theresonator dis tuned to operate at a wavelength of 9 centi metres, the electrode 6 may comprise a cylinder, about 6 millimetres in diameter and the length of the cylinder may be about 3 millimetres. The distance between the rear wall of the resonator and the reflecting electrode may be about 5 or 6 millimetres. The diameter of the apertures forming the gap in the resonator 4 may be about 3 or 4 millimetres in diameter.
The device shown is intended to be employed with an electron beam of a substantially circular form in cross section and in this case the further electrode 6 will also preferably be of circular form in cross section. Instead, however, of employing a cylindrical electrode one or more apertured diaphragms may be employed, these apertured diaphragms also serving to provide the required field gradients and by employing more than one apertured diaphragm or more than one of the cylindrical electrodes, shorter in length than that mentioned above, and maintaining these electrodes at potentials which are progressively more negative towards the reflecting electrode 5, the distance along the path of the electrons over which the concave equi-potential surfaces are set up can be increased, and the field gradient can be caused to approach closer to the zero field gradient referred to above.
' The features of the present invention can also be applied to electron discharge devices which employ ribbon-shaped beams. In this case the further electrode 6 will be shaped appropriately and may comprise a cylinder having an elongated cross-section or a diaphragm having an elongated opening or, alternatively, may comprise a pair of flat strips lying substantially parallel to the major axis of the ribbon-shaped beam as viewed in cross section. The pair of strips will be maintained at the same potential.
The features of the invention can also be applied to electron discharge devices where an electron stream flows radially through an annular gap in a resonator. In this case the further electrode may comprise a pair of rings lying one on each side of the beam.
What I claim is:
1. A high frequency apparatus including a source of electrons and an electrode toward which said electrons are to be directed, and a cavity resonator positioned between said source of electrons and said electrode, electrode means between said resonator and said electrode, means including a source of voltage and conductors connected between said source of voltage and said resonator, said electrode and said electrode means for maintaining said resonator at a high positive potential with respect to said cathode, said electrode at a negative potential with respect to said cathode, and said electrode means at a potential intermediate that of the resonator and said electrode.
2. A high frequency apparatus including a source of electrons and an electrode toward which said electrons are to be directed, and a cavity resonator positioned between said source of electrons and said electrode, electrode means between said resonator and said electrode, said electrode means comprising a tubular ring-like member closely surrounding the electron path and spaced closely adjacent said resonator and said electrode, means including a source of voltage and conductors connected between said source of voltage and said resonator, electrode and electrode means for maintaining said resonator at a high positive potential with respect to said cathode, and said electrode at a negative potential with respect to said cathode, and said electrode means at a potential intermediate that of the resonator and said electrode.
3. A high frequency apparatus includin an electron discharge device having a source of electrons and an electrode toward which said electrons are to be directed, a cavity resonator positioned between said cathode and said electrode and through which electrons are directed during operation of said apparatus, and only a single tubular electrode means positioned between said resonator and said electrode and through which the path of the electrons extends between said resonator and said electrode and closely sur- ,5 rounding said path, said resonator having a flat surface adjacent said tubular electrode means and transverse to the path of the electrons, and a voltage source having conductors connected between said voltage source, said resonator, electrode and electrode means for applying a positive potential to said resonator and a negative potential to said electrode with respect to said cathode, and a potential intermediate said two potentials to said tubular electrode means, whereby the field gradient along the path of the electrons between the resonator and the electrode has a value other than negative at least half the distance between the middle of the gap in the resonator and the zero equipotential surface 15 2,190 511 which is set up in the space between the resonator and the reflecting electrode.
STANLEY HILL.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS '10 Number Name Date 2,325,865 Litton Aug. 3, 1943 2,242,249 Varian et al May 20, 1941 2,329,778 Nergaard Sept. 21, 1943 2,293,151 Linder Aug. 18, 1942 Cage Feb, 13, 1940
US485290A 1941-01-17 1943-05-01 Electron discharge device and associated circuit Expired - Lifetime US2417551A (en)

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2489156A (en) * 1943-03-09 1949-11-22 Westinghouse Electric Corp Oscillation generator of the reflex type
US2495289A (en) * 1943-11-12 1950-01-24 Westinghouse Electric Corp Electron discharge device
US2523776A (en) * 1941-12-16 1950-09-26 Electric & Mustical Ind Ltd Electrion discharge device with hollow resonator
US2538669A (en) * 1940-12-02 1951-01-16 Hartford Nat Bank & Trust Co Electron tube system of the velocity modulation type
US2581408A (en) * 1947-04-16 1952-01-08 Sperry Corp High-frequency electron discharge device
US2598925A (en) * 1946-06-25 1952-06-03 Rca Corp Method and means for generating electrical energy from a radioactive source
US2680826A (en) * 1948-05-01 1954-06-08 Sylvania Electric Prod Stabilized klystron
US2707771A (en) * 1946-07-05 1955-05-03 Sylvania Electric Prod Electron discharge device of the dynatron oscillator type
US2777967A (en) * 1946-04-18 1957-01-15 George H Vineyard High frequency oscillator

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2190511A (en) * 1938-03-01 1940-02-13 Gen Electric Ultra short wave system
US2242249A (en) * 1938-06-18 1941-05-20 Univ Leland Stanford Junior Electrical converter
US2293151A (en) * 1940-10-08 1942-08-18 Rca Corp Resonant cavity device
US2325865A (en) * 1940-08-17 1943-08-03 Int Standard Electric Corp Electrode structure for velocity modulation tubes
US2329778A (en) * 1941-10-30 1943-09-21 Rca Corp Electron discharge device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2190511A (en) * 1938-03-01 1940-02-13 Gen Electric Ultra short wave system
US2242249A (en) * 1938-06-18 1941-05-20 Univ Leland Stanford Junior Electrical converter
US2325865A (en) * 1940-08-17 1943-08-03 Int Standard Electric Corp Electrode structure for velocity modulation tubes
US2293151A (en) * 1940-10-08 1942-08-18 Rca Corp Resonant cavity device
US2329778A (en) * 1941-10-30 1943-09-21 Rca Corp Electron discharge device

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2538669A (en) * 1940-12-02 1951-01-16 Hartford Nat Bank & Trust Co Electron tube system of the velocity modulation type
US2523776A (en) * 1941-12-16 1950-09-26 Electric & Mustical Ind Ltd Electrion discharge device with hollow resonator
US2489156A (en) * 1943-03-09 1949-11-22 Westinghouse Electric Corp Oscillation generator of the reflex type
US2495289A (en) * 1943-11-12 1950-01-24 Westinghouse Electric Corp Electron discharge device
US2777967A (en) * 1946-04-18 1957-01-15 George H Vineyard High frequency oscillator
US2598925A (en) * 1946-06-25 1952-06-03 Rca Corp Method and means for generating electrical energy from a radioactive source
US2707771A (en) * 1946-07-05 1955-05-03 Sylvania Electric Prod Electron discharge device of the dynatron oscillator type
US2581408A (en) * 1947-04-16 1952-01-08 Sperry Corp High-frequency electron discharge device
US2680826A (en) * 1948-05-01 1954-06-08 Sylvania Electric Prod Stabilized klystron

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FR920316A (en) 1947-04-03
CH267797A (en) 1950-04-15

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