US3885192A - Fundamental coupled travelling wave tube having a periodic permanent magnetic focussing structure - Google Patents

Fundamental coupled travelling wave tube having a periodic permanent magnetic focussing structure Download PDF

Info

Publication number
US3885192A
US3885192A US442884A US44288474A US3885192A US 3885192 A US3885192 A US 3885192A US 442884 A US442884 A US 442884A US 44288474 A US44288474 A US 44288474A US 3885192 A US3885192 A US 3885192A
Authority
US
United States
Prior art keywords
plates
apertured
travelling wave
wave tube
magnetic
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
US442884A
Other languages
English (en)
Inventor
Maurice Esterson
Robin Charles Moorehouse King
John Frederick Gregory
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.)
Teledyne UK Ltd
Original Assignee
English Electric Valve Co Ltd
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
Application filed by English Electric Valve Co Ltd filed Critical English Electric Valve Co Ltd
Application granted granted Critical
Publication of US3885192A publication Critical patent/US3885192A/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
    • 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
    • H01J23/0873—Magnetic focusing arrangements with at least one axial-field reversal along the interaction space, e.g. P.P.M. focusing

Definitions

  • 315/15; 315/535; 335/210 constituted by a relatively thick apertured rr [Sl] Int. Cl. H01j 26/34 magnetic Plate between two thinner ferromagnetic [58] Field of Search H 315/534! 535, apertured plates, the thinner plates extending the mag- 210 netic path provided by the thicker plate towards the electron beam path.
  • This invention relates to travelling wave tubes and more specifically to travelling wave tubes of the kind which will hereinafter be referred to as fundamental coupled cavity travelling wave tubes.”
  • the well-known so-called cloverleaf" and centipede" travelling wave tubes are tubes of this kind.
  • the object of the invention is to provide improved high power travelling wave tubes of the kind referred to in which periodic permanent magnet (P.P.M.) focusing is provided by permanent magnet systems of high efficiency and conveniently small bulk and weight.
  • Coupled cavity travelling wave tubes may be regarded, for present purposes, as divided into two classes, namely the space harmonic coupled cavity type and the type to which the present invention relates, namely the fundamental coupled cavity type.
  • the former type lends itself admirably to the use of P.P.M. focusing but grave difficulties oppose themselves to the application of P.P.M. focusing to tubes of the latter type.
  • the present invention seeks to overcome these difficulties.
  • FIG. I which is provided for purposes of introductory explanation, is a schematic cross-sectional view, taken on the centre line C/L, showing one magnet length of a known P.P.M. focusing system in a coupled cavity travelling wave tube of the space harmonic coupled cavity type.
  • the cavity coupling plates which are slotted or apertured in any of the customary ways (though, owing to the nature of the drawing in FIG. I, the slots or apertures do not appear in that figure) are employed as magnet poles. Two of these plates, 1 and 2, are represented in FIG. 1.
  • the permanent magnetic field is provided by a ring magnet 3 the polarity of which is conventionally indicated by the letters N and S.
  • FIG. 2 shows examples of such plates though, as will be well understood, there are other known forms of plate which could be used.
  • Five plates, reference X1, X2 and X3 and Y1 and Y2 are shown in FIG. 2.
  • the plates X1, X2 and X3 are alike and have tapered radially inward projections P as shown.
  • the plates Y1 and Y2. which are thinner than the plates X1, X2 and X3, are also alike and have central beam passing holes H and radial coupling slots S.
  • the X and Y plates alternate in the stack, the plates being aligned so that their outer surfaces lie in a cylindrical surface with the holes H in alternate plates in the stack also aligned.
  • the relative rotational positions of the plates are such that all the Y plates have their radial slots aligned but successive X plates are rotationally staggered or twisted (through 30 in this particular example, in which each X plate has six inward projections) so that, with an order of stacking of X1, Y1, X2, Y2, X3 and so on, the rotational positions of the plates are as represented in FIG.
  • the stack is formed as a mechanical unit, for example, by brazing, to form with end members (not shown) a vacuum tight structure, one end member carrying an axially positioned electron gun (not shown) and the other carrying an axially positioned electron collector (also not shown).
  • end members not shown
  • end member carrying an axially positioned electron gun
  • the other carrying an axially positioned electron collector (also not shown).
  • the resulting structure is well known and constitutes one well-known form of clover leaf travelling wave tube. It will readily be seen that, in such a structure, there is no room for drift-tube-like pole pieces such as the pole pieces IA and 2A of FIG. 1.
  • a fundamental coupled cavity travelling wave tube comprising a stack of slotted or apertured plates assembled to provide a plurality of successive cavities coupled for the fundamental mode of operation has, at each nth cavity (where n is an integer greater than unity) a magnetic pole piece constituted by a relatively thick apertured plate made of ferromagnetic material and which is between a pair of thinner apertured plates which are also made of ferro-magnetic material and which extend the ferromagnetic path provided by said relatively thick plate to the close neighbourhood of the electron beam path of the tube.
  • ring shaped external magnets are provided in such positions and are of such lengths as to cooperate to provide permanent magnetic fields through the pole pieces.
  • the relatively thick ferro-magnetic plates which form parts of the pole pieces are of larger external diameter than the other plates so that their rims project outwardly from what would otherwise be the smooth cylindrical outer surface of the stack, and ring magnets are positioned each in the space between successive projecting rims.
  • the value of it may be 2 but it is prefera bly at least 3.
  • tapering is required in a tube in accordance with this invention it is, therefore, preferred to effect it by a method which does not involve variation of cavity height, for if cavity height is uniform from one end of the tube to the other, the sep' aration of the pole pieces and the lengths of the magnets will also be uniform and this has obvious advantages from the point of view of practical manufacture.
  • FIG. 1 illustrates P.P.M. focussing in a prior art space harmonic coupled cavity tube
  • FIG. 2 illustrates a conventional arrangement of plates in a fun damental coupled cavity tube
  • the tube comprises a stack of plates which are assembled to provide a succession of cavities coupled for the fundamental mode of operation.
  • the plates which are shown unshaded in FIG. 3 are made of copper: those which are shown crosshatched in the figure are made of ferromagnetic mate rial preferably of soft iron.
  • the plates referenced Y in FIG. 3 are made of copper and each has a central hole and is radially slotted like the plates Y1 and Y2 of FIG. 2.
  • the stack includes plates referenced MY which are like the plates Y except that they are made of ferro-magnetic material, such as soft iron. instead of copper.
  • the stack also includes soft iron plates MX which are also of ferro-magnetic material and each of which is between two adjacent iron plates MY as shown.
  • One of these plates MX is shown in face view in FIG. 4. As will be seen each of the plates MX is like the plates X except that it is made of ferromagnetic material and is of larger external diameter so that.
  • Permanent ring magnets 3 are fitted externally of the said cylindrical surface between the projecting rims of adjacent plates MX so that these plates act as pole pieces for the magnets.
  • Such pole pieces are provided at every nth cavity in the example illustrated at every fourth cavity and in this way the pole pieces, each consisting of a plate MX in effect extended towards the electron beam by the plates MY between which it is positioned, serve the required purpose of enabling a sufficiently strong magnetic axial field to be produced in the close neighbourhood of the beam, thus providing satisfactory P.P.M. focusing.
  • the P.P.M. focusing system consisting of the permanent magnets and their associated pole pieces, is compact. economical of space and of relatively light weight, especially if materials such as Samarium Cobalt, are used in the construction.
  • the plates used in the stack are, of course, assembled in the manner already described and known per se in clover leaf and like travelling wave tubes: that is to say the radially slotted plates are assembled with their central holes aligned and their radial slots aligned, while the other plates, whether of copper or of ferromagnetic material, are assembled so that the apertures in alternate ones of these plates are aligned while the remaining ones of these plates are staggered or twisted rotationally with respect thereto in the example illustrated. by 30.
  • FIG. 5 shows a modification of the arrangement of FIG. 3.
  • the outer annular portions of the soft iron plates MX which project beyond the adjacent soft iron plates MY are much thinner than the central portions. This permits the permanent ring magnets 3 to be larger than would otherwise be the case, and allows a higher peak magnetic field to be achieved on the axis of the travelling wave tube.
  • FIG. 6 shows a further modification which can be adopted for applications in which the operating frequency of the travelling wave tube permits the use of soft iron plates MY which are sufficiently thick to carry the required magnetic flux, without assistance from the plates MX. In this case only sufficient overlap between plates MY and MX is provided to ensure good flux linkage.
  • each soft iron plate MXS possesses complete circular symmetry and surrounds copper projections X5 which are brazed to it. Six copper projectors X5 are brazed to each plate MX, and the resulting structure is as illustrated in FIG. 7.
  • the invention is not limited to the use of plates with the particular configurations of slotting and aperturing illustrated.
  • a coupled cavity travelling wave tube including a stack of alternately slotted and apertured plates assembled to provide a plurality of successive coupled cavities coupled for the fundamental mode of operation;
  • pole piece provided at each nth cavity (where n is an integer greater than 2) which pole piece consists of an apertured plate made of ferromagnetic material and positioned between a pair of thinner slotted plates which also consist of ferromagnetic material and which have regions extending the ferromagnetic path, provided by the first mentioned apertured plate, close to the electron beam path of the tube, each pair of said thinner slotted plates being spaced apart from each other by the thickness of the first mentioned apertured plate to define a cavity between them; a periodic permanent magnetic focussing structure surrounding said stack and consisting of ring shaped magnets which provide permanent magnetic fields through said pole pieces to said electron beam path.
  • each of said ferro-magnetic apertured plates contains a central aperture into which ferro-magnetic projections, which are extensions thereof project towards the central axis of the travelling wave tube.
  • each of said ferro-magnetic apertured plates contains a central aperture into which copper projections are arranged to project towards the central axis of the travelling wave tube.
  • a stack of plates comprising a set of apertured plates each having an outer, rim-like portion and a plurality of radially inwardly directed projections whose tips define a minimum diameter of its aperture and a set of slotted plates having central openings which are of much smaller diameter than said minimum diameter of the apertured plates, said apertured and slotted plates being alternated in said stack so that each apertured plate is sandwiched between two of said slotted plates and a cavity is defined between the two slotted plates sandwiching each apertured plate, each slotted plate having slots coupling the cavities with which it is associated and the slots of all of said slotted plates being aligned while the projections of said apertured plates are rotationally staggered sequentially through said stack to provide the fundamental coupled cavity structure; and
  • each pole structure comprising an apertured plate having its rim-like portion of extended outer diameter and with at least such rim-like portion being of ferromagnetic material and a pair of slotted plates of ferromagnetic material sandwiching such apertured plate therebetween, the apertured plates and slotted plates which do not form pole structures being formed of electrically conductive, nonmagnetic material and having outer diameters lying on a cylindrical surface from which said extended rim-like portions project, each ring-like permanent magnet embracing said cylindrical surface between a pair of pole structures and having opposite pole faces engaging the extended rim-like portions of such pair of pole structures.

Landscapes

  • Microwave Tubes (AREA)
  • Reciprocating Pumps (AREA)
US442884A 1973-02-16 1974-02-15 Fundamental coupled travelling wave tube having a periodic permanent magnetic focussing structure Expired - Lifetime US3885192A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB768273A GB1451956A (en) 1973-02-16 1973-02-16 Travelling wave tubes

Publications (1)

Publication Number Publication Date
US3885192A true US3885192A (en) 1975-05-20

Family

ID=9837782

Family Applications (1)

Application Number Title Priority Date Filing Date
US442884A Expired - Lifetime US3885192A (en) 1973-02-16 1974-02-15 Fundamental coupled travelling wave tube having a periodic permanent magnetic focussing structure

Country Status (6)

Country Link
US (1) US3885192A (enrdf_load_stackoverflow)
JP (1) JPS5025167A (enrdf_load_stackoverflow)
CA (1) CA1000853A (enrdf_load_stackoverflow)
DE (1) DE2319689B2 (enrdf_load_stackoverflow)
FR (1) FR2218643B1 (enrdf_load_stackoverflow)
GB (1) GB1451956A (enrdf_load_stackoverflow)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3958147A (en) * 1975-06-06 1976-05-18 Hughes Aircraft Company Traveling-wave tube with improved periodic permanent magnet focusing arrangement integrated with coupled cavity slow-wave structure
US4041349A (en) * 1973-02-16 1977-08-09 English Electric Valve Company Limited Travelling wave tubes
US4057748A (en) * 1975-03-08 1977-11-08 English Electric Valve Company Ltd. Travelling wave tubes
US4072877A (en) * 1976-07-30 1978-02-07 English Electric Valve Co., Ltd. Travelling wave tubes
US4103207A (en) * 1977-03-11 1978-07-25 Litton Systems, Inc. Coupled cavity type traveling wave tube having improved pole piece structure
US4399389A (en) * 1980-04-01 1983-08-16 Thomson-Csf Travelling wave tube with coupled cavities and focusing by alternating permanent magnets and amplifying system comprising such a tube
US4560904A (en) * 1982-12-30 1985-12-24 Siemens Aktiengesellschaft Traveling-wave tube with a periodic permanent-magnet focusing system
US4746833A (en) * 1985-04-24 1988-05-24 English Electric Valve Company Limited Coupled cavity travelling wave tubes
US5754006A (en) * 1995-03-31 1998-05-19 Nec Corporation Broad-band traveling-wave tube with offsets on pole pieces and spacers
US20100155597A1 (en) * 2008-12-23 2010-06-24 Carl Zeiss Nts Gmbh Particle optical device with magnet assembly
WO2011006588A1 (de) * 2009-07-11 2011-01-20 Karlsruher Institut für Technologie Vorrichtung zur vermeidung von parasitären schwingungen in elektronenstrahlröhren
CN102163528A (zh) * 2011-03-10 2011-08-24 安徽华东光电技术研究所 一种多注耦合腔行波管慢波结构及其制作方法

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1528155A (en) * 1973-02-16 1978-10-11 English Electric Valve Co Ltd Travelling wave tubes
US4433270A (en) * 1980-01-28 1984-02-21 Drozdov Sergei S Reversible periodic magnetic focusing system
JPS62191690A (ja) * 1986-02-17 1987-08-22 Tokico Ltd 横置型スクロ−ル圧縮機

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3010047A (en) * 1959-03-09 1961-11-21 Hughes Aircraft Co Traveling-wave tube
US3324339A (en) * 1964-02-27 1967-06-06 Hughes Aircraft Co Periodic permanent magnet electron beam focusing arrangement for traveling-wave tubes having plural interaction cavities in bore of each annular magnet
US3443146A (en) * 1966-02-16 1969-05-06 Westinghouse Electric Corp Conductive elements interconnecting adjacent members of the delay structure in a traveling wave tube
US3448326A (en) * 1966-12-08 1969-06-03 Varian Associates Twt with cloverleaf slow-wave circuit having specially shaped coupling slots
US3617802A (en) * 1970-05-06 1971-11-02 Us Navy Traveling wave tube
US3755706A (en) * 1972-03-20 1973-08-28 Varian Associates Miniaturized traveling wave tube

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3010047A (en) * 1959-03-09 1961-11-21 Hughes Aircraft Co Traveling-wave tube
US3324339A (en) * 1964-02-27 1967-06-06 Hughes Aircraft Co Periodic permanent magnet electron beam focusing arrangement for traveling-wave tubes having plural interaction cavities in bore of each annular magnet
US3443146A (en) * 1966-02-16 1969-05-06 Westinghouse Electric Corp Conductive elements interconnecting adjacent members of the delay structure in a traveling wave tube
US3448326A (en) * 1966-12-08 1969-06-03 Varian Associates Twt with cloverleaf slow-wave circuit having specially shaped coupling slots
US3617802A (en) * 1970-05-06 1971-11-02 Us Navy Traveling wave tube
US3755706A (en) * 1972-03-20 1973-08-28 Varian Associates Miniaturized traveling wave tube

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4041349A (en) * 1973-02-16 1977-08-09 English Electric Valve Company Limited Travelling wave tubes
US4057748A (en) * 1975-03-08 1977-11-08 English Electric Valve Company Ltd. Travelling wave tubes
US3958147A (en) * 1975-06-06 1976-05-18 Hughes Aircraft Company Traveling-wave tube with improved periodic permanent magnet focusing arrangement integrated with coupled cavity slow-wave structure
US4072877A (en) * 1976-07-30 1978-02-07 English Electric Valve Co., Ltd. Travelling wave tubes
US4103207A (en) * 1977-03-11 1978-07-25 Litton Systems, Inc. Coupled cavity type traveling wave tube having improved pole piece structure
US4399389A (en) * 1980-04-01 1983-08-16 Thomson-Csf Travelling wave tube with coupled cavities and focusing by alternating permanent magnets and amplifying system comprising such a tube
US4560904A (en) * 1982-12-30 1985-12-24 Siemens Aktiengesellschaft Traveling-wave tube with a periodic permanent-magnet focusing system
US4746833A (en) * 1985-04-24 1988-05-24 English Electric Valve Company Limited Coupled cavity travelling wave tubes
US5754006A (en) * 1995-03-31 1998-05-19 Nec Corporation Broad-band traveling-wave tube with offsets on pole pieces and spacers
US20100155597A1 (en) * 2008-12-23 2010-06-24 Carl Zeiss Nts Gmbh Particle optical device with magnet assembly
US8063364B2 (en) * 2008-12-23 2011-11-22 Carl Zeiss Nts Gmbh Particle optical device with magnet assembly
WO2011006588A1 (de) * 2009-07-11 2011-01-20 Karlsruher Institut für Technologie Vorrichtung zur vermeidung von parasitären schwingungen in elektronenstrahlröhren
CN102163528A (zh) * 2011-03-10 2011-08-24 安徽华东光电技术研究所 一种多注耦合腔行波管慢波结构及其制作方法
CN102163528B (zh) * 2011-03-10 2013-05-15 安徽华东光电技术研究所 一种多注耦合腔行波管慢波结构及其制作方法

Also Published As

Publication number Publication date
FR2218643B1 (enrdf_load_stackoverflow) 1978-10-27
GB1451956A (en) 1976-10-06
DE2319689A1 (de) 1974-09-05
CA1000853A (en) 1976-11-30
JPS5025167A (enrdf_load_stackoverflow) 1975-03-17
FR2218643A1 (enrdf_load_stackoverflow) 1974-09-13
DE2319689B2 (de) 1976-09-09

Similar Documents

Publication Publication Date Title
US3885192A (en) Fundamental coupled travelling wave tube having a periodic permanent magnetic focussing structure
USRE25329E (en) Periodically focused traveling wave tube
US4647887A (en) Lightweight cladding for magnetic circuits
US3324339A (en) Periodic permanent magnet electron beam focusing arrangement for traveling-wave tubes having plural interaction cavities in bore of each annular magnet
US3958147A (en) Traveling-wave tube with improved periodic permanent magnet focusing arrangement integrated with coupled cavity slow-wave structure
US2843775A (en) Electron tube magnetic focusing device
US4433270A (en) Reversible periodic magnetic focusing system
US3987333A (en) Magnetron comprising a radially magnetized permanent magnet and an axially magnetized permanent magnet
US4187444A (en) Open-circuit magnet structure for cross-field tubes and the like
US5332948A (en) X-z geometry periodic permanent magnet focusing system
US3066237A (en) Slow-wave structure
US2956193A (en) Magnet system for travelling wave tubes
US3989978A (en) Coupled cavity traveling-wave tube with oblong cavities for increased bandwidth
US4041349A (en) Travelling wave tubes
US3010047A (en) Traveling-wave tube
US3896329A (en) Permanent magnet beam focus structure for linear beam tubes
US3178602A (en) Adjustable permanent magnet focusing array
US3859613A (en) Focussing device for electronic tubes
US4057748A (en) Travelling wave tubes
US3404306A (en) Traveling-wave tube focusing field straightener
US4072877A (en) Travelling wave tubes
GB1304893A (enrdf_load_stackoverflow)
US3366904A (en) High-power multi-stage klystron with adjustable periodic magnetic focussing
US3020440A (en) Electron beam device
US3215906A (en) Periodic permanent magnet focusing stack