US2825844A - Reflex klystron oscillator tube - Google Patents

Reflex klystron oscillator tube Download PDF

Info

Publication number
US2825844A
US2825844A US395748A US39574853A US2825844A US 2825844 A US2825844 A US 2825844A US 395748 A US395748 A US 395748A US 39574853 A US39574853 A US 39574853A US 2825844 A US2825844 A US 2825844A
Authority
US
United States
Prior art keywords
tube
axis
sleeve
electron
conductive
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US395748A
Other languages
English (en)
Inventor
Charles E Rich
David E Kenyon
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.)
Unisys Corp
Original Assignee
Sperry Rand Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NL92067D priority Critical patent/NL92067C/xx
Priority to NL192105D priority patent/NL192105A/xx
Application filed by Sperry Rand Corp filed Critical Sperry Rand Corp
Priority to US395748A priority patent/US2825844A/en
Priority to GB30488/54A priority patent/GB754811A/en
Priority to FR1115629D priority patent/FR1115629A/fr
Priority to DES41783A priority patent/DE1058161B/de
Application granted granted Critical
Publication of US2825844A publication Critical patent/US2825844A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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

Definitions

  • This invention relates to ultra high frequency generators, and more particularly, is concerned with an improved reflex klystron oscillator.
  • Frequency modulation of reflex klystrons by varying the reflector voltage in response to the modulation signal is well known.
  • reflex tubes of usual construction using an ion focused beam exhibit spurious effects in their frequency modulation characteristic.
  • there may be a shift in the basic carrier frequency which is often accompanied by a large drop in the reflector electrode current.
  • frequency modulation over a band of the order of a megacycle or more is employed, frequency shifts as great as megacycles have been observed, with substantial shifts in the carrier being observed in a range from a few kilocycles to several megacycles.
  • Another object of this invention is to provide a reflex klystron which may be frequency modulated over several megacycles with a minimum of distortion due to frequency shift in the basic carrier frequency.
  • a reflex klystron of otherwise conventional design which includes a drift tube in the form of a cylindrical nickel sleeve extending be tween the cathode at one end and the resonator gap at the other end, the sleeve lying along the axis of the electron stream and having a plurality of radial vanes extending inwardly from the inner wall of the sleeve :1 distance not so great as to intercept the forward electron beam.
  • the vanes are also made of nickel and the sleeve and vanes may be carbonized to minimize secondary electron emission.
  • Fig. l is a sectional view of a reflex klystron embodying the present invention.
  • Fig. 2 is an enlarged sectional view taken on the line 22 of Fig. 1 showing the drift tube.
  • a reflex klystron of generally conventional design in which a resonant cavity 10 is part of the vacuum envelope.
  • the cavity 1% is formed by an outer cylindrical wall 12 and a solid conductive end wall 14.
  • the opposite end of the cavity includes a flexible portion 16 mounted around its outer periphery in an annular ring 18 secured to the cylindrical wall 12.
  • An electron gun 20 is positioned'within a cylindrical shell which forms part of the vacuum envelope of the tube and is secured to the lower end wall 14 of the cavity 10.
  • the gun 20 and cylindrical shell 22 are attached to a base 24 which provides electrical connections to the cathode, focusing electrode, and the heater (not shown).
  • the electron gun 20 directs a stream of electrons along the axis of the tube through the cavity 10.
  • a cylindrical tube 26 projects into the cavity and shields the electron stream from the existing electric fields thus providing a substantially field free space through which the stream of electrons passes.
  • the upper end of the tube 26 is provided with a grid 28 which together with a grid 30 in the upper end wall of the cavity 10 forms a resonator gap in which interaction between the electron beam and the electromagnetic field Within the cavity 10 takes place according to conventional reflex klystron operation for velocity modulation of the beam.
  • a smoother grid 31 Positioned at the lower end of the tube 26 is a smoother grid 31.
  • a reflector electrode 32 is positioned along the path of the electron stream for reflecting the electrons back through the resonator gap for transfer of energy to the cavity 10.
  • An electrical connection to the reflector electrode 32 is provided through a cap 34 which is supported by an insulator 36 from the metallic wall 38 forming the upper part of the vacuum envelope of the klystron.
  • Mechanical tuning of the klystron is achieved by means of adjusting screws 40 extending between the annular plate 18 and a second annular plate 42 secured to the wall 38 of the upper part of the klystron.
  • the screws 40 react against springs, such as indicated at 44, adjustment of the screws 40 varying the space between the plates 18 and 42 and thereby varying the spacing between the grids 28 and 30.
  • Spring pressure is varied by means of studs 45 mounted on the plate 18 and extending up through the center of the springs, and adjusting nuts 47 threaded on the studs as shown.
  • An output signal is derived from the cavity 10 by means of a coaxial line coupler indicated generally at 46, the inner conductor 48 of which extends as a probe within the cavity 10.
  • the reflex klystron as thus far described, when employed in C. W. operation with frequency modulation, is subject to the spurious effects as mentioned above, namely, at certain discrete frequencies of modulation, there is a sharp shift in the basic carrier frequency which is frequently accompanied by a drop in reflector electrode current and a drop in the FM output.
  • spurious effects have been substantially overcome by providing, in accordance with the present invention, a plurality of conductive fins or vanes 50, preferably made of nickel, around the inner wall of a nickel cylindrical sleeve 52 pressed into the tube 26, as seen in Fig. 2.
  • These vanes are preferably made in the form of channel members which are spot welded to the inner wall of the sleeve 52.
  • vanes thus formed project toward the region of the electron stream but are designed so as not to actually intercept the incident beam but rather to define a cylindrical passage through the vanes of suflicient diameter to permit unimpaired passage of the electron stream from the cathode through the tube 26. Also to prevent interception of the electron stream by the vanes, they are made so as not to extend the full length of the tube 26, but are terminated some distance away from the smoother grid 31 in the region where the electron stream is considerably spread out as it emerges from the gun 20. It
  • vanesrin suppressing the spurious effects associated with frequency modulation operation of a reflex kylstron may be best understood by considering the theory as presently developed on the cause of the carrier shift.
  • the electron stream from the cathode is directed through the tube 26 toward the resonator gap.
  • the electrons reflected by the reflecting electrode by the time they again pass through the resonato-r'gap, are fairly well scattered and strike the wall of the tube 26 causing secondary electrons to be emitted.
  • These secondary electrons have no noticeable detrimental eflect on the'kylstron operation so long as the klystron is unmodulated.
  • the reflector voltage When the reflector voltage is varied during modulation, the returning electrons strike the wall in such manner that the production of secondaries at any one point is also modulated, thus exciting the plasma oscillation.
  • This oscillation of the ion plasma causes an enlargement of the beam diameter and subsequent shift in frequency of the carrier. Since the power output and frequency of a klystron are dependent on beam diameter, the spreading of the beam in the resonator gap at the modulation frequencies where plasma oscillation is excited gives rise to the described spurious effects in the klystron operation.
  • Provision of the radial vanes within the tube 26 acts to prevent plasma oscillation in two ways. First, by their geometry they tend to trap a large portion of the secondary electrons produced in the tube 26 and so prevent their entering the ion plasma. Second, the radial fins alter the potential variation particularly in the region near the walls of the tube 26 and thereby remove the condition for maintaining plasma oscillation in the ion gas.
  • the reflex klystron tube may be frequency modulated by changing the reflector electrode voltage, the modulation'frequency being variable over a video frequency'band with negligible shift in the carrier frequency.
  • This improved performance is achieved by novel means including a plurality of radially projecting fins in the ion focusing region, the fins modifying the potential gradient between the electron beam and the wall of the tube and also trapping secondary electrons emitted by the wall 'of the tube by the scattered reflected electrons.
  • An electron discharge tube comprising means for producing an electron stream directed along an axis, means positioned along said axis for reflecting the electron stream back along said axis, a cylindrical conductive sleeve having its axis of revolution aligned with the axis of the electron stream, the sleeve being positioned between the electron stream producing means and the reflecting means, first grid across one end of the sleeve, a second grid across the other end of the sleeve, a plurality of conductive fins projecting substantially radially and inwardly from the inner surface of the sleeve, the inner longitudinal edges of the fins being spaced from the axis of the electron stream so as to permit passage of the forward electron stream through the sleeve without interception v by the fins, the fins and the sleeve having carbonized surfaces, and a single cavity resonator positioned along the stream for interaction therewith at a point intermediate the reflector means and the end of the conductive sleeve.
  • An electron discharge tube comprising means for producing an electron stream directed along an axis, means positioned along said axis for reflecting the electron stream along said axis, a cylindrical conductive sleeve having its axis of revolution aligned with the axis of the electron stream, the sleeve being positioned between the electron stream producing means and the reflecting means, a first grid across one end of the sleeve, a second grid across the other end of the sleeve, and a plurality of conductive fins projecting substantially radially and inwardly from the inner surface of the sleeve, the inner longitudinal edges of the fins being spaced from the axis of the electron stream so as to permit passage of the forward electron stream through the sleeve without interception by the fins, the fins and the sleeve having carbonized surface.
  • An electron discharge tube comprising means for producing an electron stream directed along an axis, means positioned along said axis for reflecting the electron stream back along said axis, a cylindrical'conductive sleeve having its axis of revolution aligned with the axis of the electron stream, the sleeve being positioned between the electron stream producing means and the reflecting means, and a plurality of conductive fins projecting substantially radially and inwardly from the inner surface of the sleeve, the inner longitudinal edges of the fins being spaced from the axis of the electron stream so as to permit passage of the forward electron stream through the sleeve without interception by the fins, the fins and the sleeve having carbonized surfaces.
  • High frequency electron beam apparatus comprising tubular conductive means defining a substantially field free space, means aligned with said conductive means at one end thereof for projecting an electron-beam having a predetermined boundary through said space, means for reflecting said beam back into said conductive means, and means including a plurality of conductive members associated with said conductive means and projecting substantially radially inwardly into said space along a substantial portion of the-path of said beam within said space for trapping secondary electrons released by the impingement of electrons of said reflected beam upon said conductive means and members, said conductive members being spaced from said beam boundary for precluding interception of the beam electrons contained by said boundary.
  • High frequency electron beam apparatus comprising conductive means defining a substantially field free space, means defining a velocity modulation gap at One end of said conductive means, means aligned with said conductive means at-the other'end thereof for projecting an electron beam having a predetermined boundary through said space and across said gap, means for reflecting said beam back across said gap and into said conasaaaas ductive means, and means within said conductive means in spaced relationship with said beam boundary for trapping secondary electrons released by impingement of the electrons of said reflected beam upon said conductive means.
  • an ion-focusing reflex klystron having a conductive tube defining a substantially field free space between the cathode and reflecting electrode of the klystron, a plurality of radially projecting conductive fins secured to the inner surface of the conductive tube, the fins extending longitudinally over a substantial portion of the length of the conductive tube and defining a cylindrical passage of a diameter larger than the diameter of the electron beam.
  • a reflex klystron comprising cathode means for producing a beam of electrons having a predetermined boundary directed along an axis, a reflector electrode positioned along the axis and spaced from the cathode means for intercepting and reflecting the beam back along the axis, a single cavity resonator positioned along the axis and having a velocity modulation gap for interaction with the electron beam at a point intermediate the cathode means and reflector electrode, and means defining a substantially field free space for the electron beam along the axis between the cathode means and the velocity modulation gap of said cavity resonator, said last-named means including conductive means defining a plurality of elongated passages parallel with the axis of the beam for trapping secondary electrons produced by interception of the reflected electrons from the reflector electrode by the field free space defining means, said conductive means being spaced from said predetermined beam boundary for precluding interception of beam electrons contained by said boundary.
  • a reflex klystron comprising cathode means for producing a beam of electrons having a predetermined boundary directed along an axis, a reflector electrode positioned along the axis and spaced from the cathode means for intercepting and reflecting the beam back along the axis, a single cavity resonator positioned along the axis for interaction with the electron beam at a point intermediate the cathode means and reflector electrode, and means defining a substantially field free space for the electron beam along the axis between the cathode means and the cavity resonator, said last-named means including means along a major portion of the length of said field free space for trapping secondary electrons produced by interception of the reflected electrons from the reflector electrode by the field free space defining means.
  • An electron discharge tube comprising means for producing an electron stream directed along an axis, means positioned along said axis for reflecting the electron stream back along said axis, a cylindrical conductive sleeve having its axis of revolution aligned with the axis of the electron stream, the sleeve being positioned between the electron stream producing means and the re fleeting means, and a plurality of conductive fins projectsnbstantially radially and inwardly from the inner surface of the sleeve, the inner longitudinal edges of the fins being spaced from the axis of the electron stream so as to permit passage of the forward electron stream through the sleeve without interception by the fins.
  • a reflex klystron comprising means including a cathode for producing and directing an electron beam having a predetermined boundary along a predetermined axis, a cavity resonator having a reentrant electron permeable metallic tube portion followed by a velocity modulating gap in axial alignment with said beam, the inner diameter of said tube portion being larger than said beam boundary, means positioned along said axis beyond said gap for reflecting the electrons of said beam back along said axis past said gap and into said tube portion, and means along said tube portion between the inner wall thereof and the boundary of said beam for substantially isolating said beam in its path toward said reflecting means from secondary electrons within said tube portion.

Landscapes

  • Particle Accelerators (AREA)
US395748A 1953-12-02 1953-12-02 Reflex klystron oscillator tube Expired - Lifetime US2825844A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NL92067D NL92067C (is") 1953-12-02
NL192105D NL192105A (is") 1953-12-02
US395748A US2825844A (en) 1953-12-02 1953-12-02 Reflex klystron oscillator tube
GB30488/54A GB754811A (en) 1953-12-02 1954-10-22 Reflex klystron oscillator tube
FR1115629D FR1115629A (fr) 1953-12-02 1954-11-18 Tube électronique à réflexion à atmosphère gazeuse
DES41783A DE1058161B (de) 1953-12-02 1954-12-01 Reflexklystron

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US395748A US2825844A (en) 1953-12-02 1953-12-02 Reflex klystron oscillator tube

Publications (1)

Publication Number Publication Date
US2825844A true US2825844A (en) 1958-03-04

Family

ID=23564338

Family Applications (1)

Application Number Title Priority Date Filing Date
US395748A Expired - Lifetime US2825844A (en) 1953-12-02 1953-12-02 Reflex klystron oscillator tube

Country Status (5)

Country Link
US (1) US2825844A (is")
DE (1) DE1058161B (is")
FR (1) FR1115629A (is")
GB (1) GB754811A (is")
NL (2) NL192105A (is")

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264513A (en) * 1961-09-06 1966-08-02 English Electric Valve Co Ltd Deformable wall tuning of resonant cavities for electron discharge tubes

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2497564A (en) * 1945-05-02 1950-02-14 Sperry Corp High-frequency apparatus
US2581408A (en) * 1947-04-16 1952-01-08 Sperry Corp High-frequency electron discharge device
US2608670A (en) * 1942-01-29 1952-08-26 Sperry Corp High-frequency tube structure

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE471464A (is") * 1943-09-21
NL154330B (nl) * 1950-06-21 Glaverbel Werkwijze en voorwerp voor het omkeerbaar wijzigen van lichtreflectie.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2608670A (en) * 1942-01-29 1952-08-26 Sperry Corp High-frequency tube structure
US2497564A (en) * 1945-05-02 1950-02-14 Sperry Corp High-frequency apparatus
US2581408A (en) * 1947-04-16 1952-01-08 Sperry Corp High-frequency electron discharge device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264513A (en) * 1961-09-06 1966-08-02 English Electric Valve Co Ltd Deformable wall tuning of resonant cavities for electron discharge tubes

Also Published As

Publication number Publication date
FR1115629A (fr) 1956-04-26
DE1058161B (de) 1959-05-27
NL92067C (is")
GB754811A (en) 1956-08-15
NL192105A (is")

Similar Documents

Publication Publication Date Title
US2276806A (en) High frequency apparatus
US2338237A (en) High-frequency electron discharge apparatus
US2304186A (en) Velocity modulated tube
US3221205A (en) Traveling-wave tube with trap means for preventing oscillation at unwanted frequencies
US2411913A (en) Electron discharge device
US2582186A (en) Apparatus for accelerating charged particles, especially electrons, to very high-velocity
US2450026A (en) Thermionic device for use with wave guides
US2466063A (en) High-power high-frequency electron discharge apparatus
US2782334A (en) Velocity modulated electron discharge devices
US3432722A (en) Electromagnetic wave generating and translating apparatus
US2638561A (en) Cathode-ray oscillator tube
US2425738A (en) Tunable high-frequency electron tube structure
US2411535A (en) High-frequency electron discharge apparatus
US2276320A (en) Centimeter wave device
US2825844A (en) Reflex klystron oscillator tube
US2254796A (en) Electron device using hollow resonator
US2748277A (en) Magnetron noise generators
US2462869A (en) Electron discharge device
US2404078A (en) Electron discharge device
US2416283A (en) Ultra high frequency electronic device
US2213543A (en) Electron discharge device
US2667598A (en) Electron discharge apparatus utilizing a cavity resonator
US2222898A (en) High-frequency apparatus
US2888610A (en) Traveling wave tubes
US2678404A (en) High-frequency electron discharge apparatus