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US3197672A - Magnetic field strength reduction near collector of m-type travelling wave tube - Google Patents

Magnetic field strength reduction near collector of m-type travelling wave tube Download PDF

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Publication number
US3197672A
US3197672A US93959A US9395961A US3197672A US 3197672 A US3197672 A US 3197672A US 93959 A US93959 A US 93959A US 9395961 A US9395961 A US 9395961A US 3197672 A US3197672 A US 3197672A
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United States
Prior art keywords
magnetic field
area
collector
tube
travelling wave
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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
US93959A
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English (en)
Inventor
Favre Maurice
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.)
Thales SA
Original Assignee
CSF Compagnie Generale de Telegraphie sans Fil SA
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Filing date
Publication date
Application filed by CSF Compagnie Generale de Telegraphie sans Fil SA filed Critical CSF Compagnie Generale de Telegraphie sans Fil SA
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    • 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
    • H01J23/08—Focusing arrangements, e.g. for concentrating stream of electrons, for preventing spreading of stream
    • H01J23/087—Magnetic focusing arrangements
    • 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
    • H01J23/10—Magnet systems for directing or deflecting the discharge along a desired path, e.g. a spiral path
    • 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
    • H01J25/42—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and with a magnet system producing an H-field crossing the E-field

Definitions

  • the present invention relates to M-type travelling wave tubes, and more particularly to improvements in the means normally provided therefor for producing the magnetic field for M-type travelling wave tubes.
  • the M-type travelling Wave tubes operate with a magnetic field essentially perpendicular to the electric field within the interaction space of the tube and to the electron beam which propagates within this interaction space.
  • this magnetic field is either constant all along the path of the beamexcept possibly within the area of the cathode where it has already been proposed to suppress or at least substantially reduce the action of the magnetic field on the electron gun by shielding of the latter, or by its location outside of the air gap of the magnet-or variable along this path with or without compensation of the variations in the electron speed due to these variations of the magnetic field by a correlated variation in the electric field.
  • the present invention provides a device for producing the magnetic field for M-type travelling wave tubes such that the magnetic field remains essentially constant along the interaction space and undergoes an annulment or at least a sharp reduction within the area of the collector.
  • This suppression or reduction of the magnetic field within the area of the collector causes a bending, with a constant electric field, of the trajectories of the electrons toward the collector in such a manner that the electrons may be captured or absorbed by a relatively large surface essentially parallel to the sole of the tube which improves the properties of thermal dissipation without creating, within the tube, disturbances or perturbations within the distribution of'the electric field of which any heterogeneity might lead to undesirable arcing or sparking within the tube.
  • the arrangement according to the presentinvention may be advantageously combined with the knownarrangement of suppression or reduction of the magnetic field within the area of the cathode. It is, therefore, preferably such that the constant magnetic field, necessary for proper operation of the tube, traverses the tube exclusively along the interaction space and be either zero or strongly weakerred outside of this space, that isat the same time within the regions of the collector and of the cathode.
  • the invention is realized in an advantageous manner by incorporating within the lateral walls of the tube auxiliary pole pieces supplementary to the regular magnets, these auxiliary pole pieces extending only along regions of the tube in which it is desired to maintain the non-reduced field, that is either over the entire tube except within the region of the collector or only along the interaction space to the exclusion of the regions of the collector and cathode.
  • these auxiliary pole pieces will assume the form of an interrupted circular ring within the opening of which are located the collector and possibly also the cathode.
  • Supplementary pole pieces of similar shape and located within the space in the same manner may also be 3,197,572 Patented July 27, 1965 secured outside of the tube over the poles of the regular magnet.
  • a magnetic shunt may be secured to the poles of the regular magnet facing the zone of desired reduction or weakening of the magnetic field.
  • an object of the present invention to provide an M-type travelling wave tube, and more particularly a magnetic field source therefor which efiectively eliminates the aforementioned drawbacks and shortcomings of the prior art constructions.
  • a further object of the present invention resides in the provision of a source for the magnetic field of M-type travelling wave tubes which permits higher power outputs from the tube without the danger of arcing or sparking within the tube that may be caused by disturbing the electric field.
  • FIGURE 1 is an axial cross sectional view through a first embodiment in accordance with the present invention, taken along line 1-1 of FIGURE Z;
  • FIGURE 2 is a transverse cross sectional view of the tube illustrated in FIGURE 1, taken along line IIII thereof;
  • FIGURE 3 is a perspective View of an external pole piece assembly in accordance with the present invention.
  • FIGURE 4 is a partial axial view of a modified embodiment in accordance with the present invention, taken along line IV-IV of FIGURE 5, and
  • FIGURE 5 is a transverse cross sectional view taken along line VV of FIGURE 4.
  • FIGURES 1 and 2 there may be found in these two views the usual elements of an M-type travelling wave tube of circular shape, namely anv anode ring 1 supporting thereon, in any suitable manner, a delay circuit 2 of any known construction-which extends over an arc of a circle, for example, over 270" between the ends 3 and 4 thereof.
  • the lateral portions 5 and 6 close, in a vacuum-tight manner, the box of the tube.
  • a sole 7 is provided within the tube, the cathode '8 being accommodated within the surface of the sole 7.
  • the tube includes a collector '9 secured to the anode ring 1.
  • the pole pieces 10 and 11 furnish the magnetic field required for proper operation of the tube.
  • auxiliary or supplementary pole pieces 12 and 13 are incorporated within the walls of the tube, these auxiliary pole pieces 12 and 13 having the shape of aninterrupted ring extending between the ends 14 and 15 thereof essentially in correspondence with the ends 3 and 4 of the delay circuit 2-, that is, essentially over the same arc of 270 in the illustrated embodiment.
  • the cathode 8 and the collector 9 are therefore located within the op'eningof the interrupted ring, and the magnetic field which traverses these regions is thereby substantially weakened with respect to the field which traverses the interaction space contiguous to the 'delay circuit 2.
  • FIGURE 3 illustrates in perspective the pole piece 11 having an auxiliary pole piece 17 of this type secured thereto.
  • the invention is applicable, in an analogous manner, to tubes of linear structure in which the auxiliary pole pieces will obviously have the shape of bars extending over any desired length of the tube.
  • the internal pieces 12 and 13 may eventually also be dispensed with if the weakening of the magnetic field produced beyond the external pieces 16 and 17 is sufficient.
  • FIGURES 4 and 5 one is illustrated in FIGURES 4 and 5 in which the same reference numerals are used again to designate corresponding parts as are used in connection with FIGURES 1, 2 and 3.
  • FIGURES 4 and 5 corresponds to a conventional circular M-type tube structure.
  • the piece 20 is a magnetic shunt secured to the magnetic poles and 11 opposite the desired zone of reduction of the magnetic field that includes the cathode 8 and the collector 9.
  • the action of the magnetic shunt is equivalent to the interruption in the rings 12 and 13 of FIGURES 1 and 2.
  • a travelling wave tube of the M-type having successively adjacent an electron gun area, an interaction area and a collector area and means including pole piece meansfor generating through said three areas a transverse magnetic field
  • the improvement essentially consisting of means for substantially reducing the field strength of said magnetic field traversing said collector area with respect to the field strength thereof traversing said interaction area including auxiliary pole piece means operatively associated with said first-mentioned pole piece means and effectively providing discontinuities within said collector area to reduce the transverse magnetic field set up by said first-mentioned pole piece means within said collector area.
  • a substantially circular travelling wave tube of the M-type having, along the circular contour thereof, successively adjacent an electron gun area, an interaction area and a collector area and means including main pole piece means for generating through said three areas a transverse magnetic field
  • the improvement essentially consisting of means for substantially reducing the field strength of said magnetic field traversing both said electron gun and collector areas with respect to the field strength thereof traversing said interaction area including auxiliary pole piece means of configuration approximately similar to and coextensive only with said interaction area to affect the iagnetic field produced by said main pole piece means within said electron gun and collector areas.
  • a travelling wave tube of the M-type having successively adjacent an electron gun area, an interaction area and a collector area and means for generating through said three areas a transverse magnetic field, including magnetic pole pieces extending along said three areas, means for substantially reducing the field strength of said magnetic field traversing said collector area with respect to the field strength thereof traversing said interaction area including additional pole pieces extending at least along said interaction area exclusive said collector area.
  • a travelling wave tube of the M-type having successively adjacent an electron gun area, an interaction area and a collector area and means for generating through said three areas a transverse magnetic field, including magnetic pole pieces extending along said three areas, means for substantially reducing the field strength of said mag netic field traversing said collector area with respect to the field strength thereof traversing said interaction area includingadditional pole pieces extending at least along said interaction area exclusive said collector area, said three areas being enclosed within two lateral covers of said tube essentially parallel to said pole pieces, and said additional pole pieces being secured to said covers within the tube.
  • a travelling wave tube of the M-type provided with an electron source area, an interaction space area and a collector area, means for generating within said areas a transverse magnetic field, including magnetic pole pieces extending along said areas, and means for substan tially reducing the field strength of said magnetic field traversing the collector area in comparison to the field strength traversing said interaction area including additional pole piece means extending at least along said interaction area but exclusive of said collector area.
  • a travelling wave tube of the M-type provided with an electron source area, an interaction space area and a collector area, means for generating within said areas a transverse magnetic field including magnetic pole pieces extending along said areas, and means for substantially reducing the field strength of said magnetic field traversing the collector area in comparison to the field strength traversing said interaction area including additional pole piece means extending at least along said interaction area but exclusive of said collector area, said additional pole piece means being fitted to said magnetic pole pieces.
  • a circular travelling wave tube of the M-type provided with an electron source area, an interaction space area and a collector area, means for generating within said areas a transverse magnetic field including magnetic pole pieces extending along said areas, said transverse magnetic field being directed essentially along the axis thereof, and means for substantially reducing the field strength of said magnetic field traversing the collector area in comparison to the field strength traversing said interaction area including additional pole piece means extending at least along said interaction area but exclusive of said collector area, said additional pole piece means being of interrupted ring shape with the ring thereof so located that at least said collector area but excluding said interaction area essentially faces the interruption thereof.
  • a travelling wave tube of the M-type provided, within an envelope, with an electron source area, an interaction space area and a collector area, a magnet system adapted to produce a transverse magnetic field, and means for effectively providing a field strength of said magnetic field traversing the collector area which is significantly smaller than the field strength of said field traversing said interaction area including auxiliary pole piece means within said envelope and coextensive substantially only with said interaction area to affect the magnetic field of said magnetic system.
  • magnet field generating means for generating within said areas a transverse magnetic field including magnetic pole pieces having surfaces essentially parallel to said covers and extending along said three areas, and means for substantially reducing the field strength of said magnetic field traversing the collector area with respect to the fi ld strength traversing said interaction area including first auxiliary pole piece means fitted 10 to said covers Within said tube and second auxiliary pole piece means fitted to said magnetic pole piece surfaces, said first and second auxiliary pole piece means extending at least along said interaction area exclusive of said collector area.

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US93959A 1960-03-29 1961-03-07 Magnetic field strength reduction near collector of m-type travelling wave tube Expired - Lifetime US3197672A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR822736A FR1260655A (fr) 1960-03-29 1960-03-29 Perfectionnements aux dispositifs de production du champ magnétique pour tubes à ondes progressives type m

Publications (1)

Publication Number Publication Date
US3197672A true US3197672A (en) 1965-07-27

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Application Number Title Priority Date Filing Date
US93959A Expired - Lifetime US3197672A (en) 1960-03-29 1961-03-07 Magnetic field strength reduction near collector of m-type travelling wave tube

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US (1) US3197672A (fr)
DE (1) DE1254775B (fr)
FR (1) FR1260655A (fr)
GB (1) GB915607A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4207495A (en) * 1978-08-30 1980-06-10 The United States Of America As Represented By The Secretary Of The Air Force Means for improving the collector efficiency of an emitting sole crossed field amplifier
US5510010A (en) * 1994-03-01 1996-04-23 Carrier Corporation Copper article with protective coating

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2745983A (en) * 1949-06-10 1956-05-15 Csf Traveling wave tube
US3027487A (en) * 1953-09-24 1962-03-27 Raytheon Co Electron discharge devices of the traveling wave type
US3084279A (en) * 1960-02-10 1963-04-02 Raytheon Co Travelling wave devices
US3123735A (en) * 1964-03-03 Broadband crossed-field amplifier with slow wave structure

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE944075C (de) * 1953-06-17 1956-06-07 Csf Wanderfeldroehrenanordnung mit gekreuzten elektrischen und magnetischen Feldern, wobei das Magnetfeld von einem in einem axialen Leiter fliessenden Strom erzeugt wird
FR1100975A (fr) * 1954-03-11 1955-09-27 Csf Montage de tubes à onde progressive pour régime impulsif avec champs électrique et magnétique croisés

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3123735A (en) * 1964-03-03 Broadband crossed-field amplifier with slow wave structure
US2745983A (en) * 1949-06-10 1956-05-15 Csf Traveling wave tube
US3027487A (en) * 1953-09-24 1962-03-27 Raytheon Co Electron discharge devices of the traveling wave type
US3084279A (en) * 1960-02-10 1963-04-02 Raytheon Co Travelling wave devices

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4207495A (en) * 1978-08-30 1980-06-10 The United States Of America As Represented By The Secretary Of The Air Force Means for improving the collector efficiency of an emitting sole crossed field amplifier
US5510010A (en) * 1994-03-01 1996-04-23 Carrier Corporation Copper article with protective coating

Also Published As

Publication number Publication date
GB915607A (en) 1963-01-16
FR1260655A (fr) 1961-05-12
DE1254775B (de) 1967-11-23

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