US3852636A - Klystrons - Google Patents

Klystrons Download PDF

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Publication number
US3852636A
US3852636A US00405545A US40554573A US3852636A US 3852636 A US3852636 A US 3852636A US 00405545 A US00405545 A US 00405545A US 40554573 A US40554573 A US 40554573A US 3852636 A US3852636 A US 3852636A
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United States
Prior art keywords
klystron
section
transmission line
gap
collector
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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
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US00405545A
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English (en)
Inventor
C Edgcombe
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Teledyne UK Ltd
Original Assignee
English Electric Valve Co Ltd
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Filing date
Publication date
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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
    • H01J23/14—Leading-in arrangements; Seals therefor
    • H01J23/15—Means for preventing wave energy leakage structurally associated with tube leading-in arrangements, e.g. filters, chokes, attenuating devices

Definitions

  • a klystron having a collector (2 and a drift tube (1) is provided with a vacuum retaining ceramic tube (8) between the drift tube and the collector.
  • the outer surface of the cermaic tube is coated with metal M and spaced from the inside surface of the ceramic tube is a deformable metal cylinder (16).
  • a transmission line TL is created and the cylinder (16) is so bent that the transmission line is a half wave length long at the mid-frequency of the operating bandwidth.
  • KLYSTRONS This invention relates to Klystrons of the so-called metal-insulation envelope type, i.e., of the type wherein the electron beam, after passing the frift tubes of the klystron, enters a hollow collector which is spaced from the adjacent end of the last drift tube by a member made of insulating material in current practice of ceramic material which forms parts of the vacuumretaining envelope of the klystron.
  • FIG. 1 of the accompanying drawings is a schematic representation, half in section in the centre line, showing, so far as is necessary to an understanding thereof, a known construction of klystron having such means. This figure shows the adjacent ends of the last drift tube and of the collector together with the parts adjacent the gap between said drift tube and collector.
  • FIG. 1 illustrates the last drift tube at the collector the collector of the last drift tube of the klystron is referenced l,- and 2 is the hollow collector.
  • the end of said collector nearer said drift tube is tapered inwardly in the customary way.
  • 3 is a cap on the electron entry end of'the collector for preventing secondary electrons from the interior thereof travelling back to the drift tube. It defines the entry aperture into the collector which, in the construction shown, is water jacketed for cooling.
  • the water jacketspace is indicated by the reference letter W. It is the space between the collector 2 and the parts referenced 4 and 5 and it contains a partition wall 6 so that water circulation is up one side of this wall anddown the other. Because the water jacket extends practically to the end of the collector, very effective water cooling is obtained.
  • a water jacket space 'W' is also provided round the drift tube 1.
  • the drifttubel is seated in a mounting flange member 7 made of ferro-magnetic material and forming part of the usual focussing magnetic circuit of the klystron.
  • the flange '7 is parallel to and spaced from the parts 3 and 4.
  • A' ceramic cylinder 8 is provided between the flange 7 and a flange 9 extending outwardly from the outer, wall of the collector water jacket.
  • the said cylinder 8 has metal coatings M on both its inner and outer surfaces. These coatings may be obtained for example by metallisation by firing on molybdenum and then nickel plating it.
  • the inner coating stops short of the end of cylinder 8 adjacent the flange 9 and the outer coating stops short of the end of said cylinder adjacent the flange 7.
  • the said cylinder 8 is fixed in position by edge of the ring member to the inside as shown. Over. the tape is placed a wrapping of aluminum or other suitable metal foil which is insulated from the ring member 10 by the tape but is in good electrical contact with the metal coating on the outer face of the ceramic cylinder 8.
  • An encircling tensioned neoprene rubber or similar elastic band 14 ensures thev maintenance of good electrical contact.
  • the inner coating M on the ceramic cylinder is in good electrical contact with the ring member 10 and the outer coating M is in good electrical contact with the ring member 11.
  • this known construction' is to provide a high frequency transmission line which extends, as indicated by the arrow headed broken line TL, radially outwards along the gap between the parts 1 and 7 on the one hand and the parts 3 and 4 on the other; then, at right angles to this portion of its length, down between the parts 5 and 8; and then turns through and extends up along the ceramic filled space between the inner and outer coatings M.
  • This transmission line is short circuited as respects high frequency at its outer end, i .e., the end outside the vacuum, by the capacitor of which the tape 12 is the dielectric and the other ring member 10 and foilwrapping 13 are the electrodes.
  • this transmission line is a half wave length long (or an integral plurality of half wavelengths long) at the intended working frequency f of the klystron then, at this frequency the high frequency short circuit provided by the aforesaid capacitor, although physically outside the vacuum and at the outer end of the transmission line, will appear as a high frequency short circuit at the inner end of the transmission line and will therefore in effect connect the collector directly to the adjacent drift tube as respects the working high frequency. Theoretically therefore, high frequency radiation through the gap should be prevented.
  • the length of the transmission line is, as already stated, composed of three portions namely the radial length portion along the gap between the part 7 on the one hand and the parts 3 and 4 on the other; the perpendicular length portion between the parts 5 and 8; and the final length portion up through the dielectric-filled space between the inner and outer coatings M.
  • the design criterion adopted has been merely to make the combined length of these three portions equal to one half wave length at the frequency f and the dimensions have been chosen to satisfy this criterion.
  • the design criterion adopted has been merely to make the combined length of these three portions equal to one half wave length at the frequency f and the dimensions have been chosen to satisfy this criterion.
  • the shape of the collector shall be properly chosen adequately to dissipate heat.
  • a klystron of the metalinsulation type having a hollow collector which is spaced from the adjacent end of the last drift tube by an insulating member which forms part of the evacuated envelope is provided withmeans for preventing high frequency radiation from the gap between the last drift tube and the collector, said means being constituted by a high frequency transmission line which is external with respect to'said gap, is short-circuited (as respects high frequency) at its outer end outside the evacuated space of the klystron, is electrically an integral number (including unity) of half wave lengths long at the centre frequency (f) of the intended working frequency band of the klystron and is also so dimensioned that it does not correspond to an electrical length which approximates to an odd number (including unity) of quarter wave lengths of any frequency or second harmonic of any frequency inside the said working band.
  • the parts constituting the transmission line include an adjustable metal member which does not form part of the evacuated envelope of the klystron and which can be adjusted (during manufacture) to modify the electrical constants of the line.
  • an adjustable metal member which does not form part of the evacuated envelope of the klystron and which can be adjusted (during manufacture) to modify the electrical constants of the line.
  • Embodiments of this nature have the practical advantage that, after the parts of the klystron have been made and assembled (but before evacuation) a high frequency source providing a frequency variable over a band corresponding with the intended working frequency band may be applied to the assembled klystron, the occurrence of radiation from the gap observed, and the adjustable member ad- 5 justed until radiation within band is bandis eliminated .or reduced to an acceptably low level, there being no need to modify or change the dimensions of any part of the envelope of the klystron in order to achieve this result.
  • the adjustable member is preferably a deformable metal member inside the insulating member of the envelope and spaced therefrom, so that the aforesaid final length of the line has dielectric in part consisting of solid dielectric (the material of the insulating member of the envelope) and in part consisting of vacuum (the space between the insulating member and the deformable member which is spaced from the inner wall of said insulating member).
  • said spaced adjustable metal member of telescopic or of bellows-like construction so that it may be adjusted by changing its physical length i.e., its length parallel to the klystron axis, it is very difficult to make such a member able to retain the length to which it,has been adjusted without resorting to the added complication of providing adjustable means for positively holding the said member at the length to which it has been adjusted, and it is considered that such added complication would not justify the expense involved in its provision. It is preferred, therefore, to constitute the spaced adjustable member by a simple cylinder of deformable metal and to deform it as required by bending it to modify its spacing from the inner wall of the insulating member of the envelope.
  • the insulating member of the envelope is provided with a metal coating which is on its outer surface only and is connected to a metal part of the klystron structure on one side only of the gap and a deformable metal cylinder connected to a metal part of the klystron structure on the other side only of said gap is provided inside said insulating member and spaced from the inner wall thereof, the length of the transmission line being thus made up of the sum of the radial length of the gap, the length of a space communicating with said gap and situated between a part of the outer surface of the collector structure and said deformable metal cylinder, and the length, parallel to the axis of the klystron, of the separation between said cylinder and the metal coating on the outer surface of the insulating member.
  • the insulating member is provided with a metal coating which is on its outer surface only and is connected to a metal part of the klystron structure on one side only of the gap, the inner surface being either free of any metal coating or, preferably, being provided with a metal coating extending only over that portion of said inner surface which is in the region of the gap, said coating being connected to a metal part of the klystron on the side of the gap other than that to which the outer coating is connected.
  • the invention also provides a method of adjusting a klystron in accordance with the invention and having an adjustable member for adjusting the electrical constants of the transmission line.
  • This method consists of inserting a probe axially in the assembled klystron (before itis evacuated), supplying high frequency energy including frequencies within the intended operating frequency band of the klystron from a high frequency source to said probe, observing the frequency or frequencies at which radiation occurs from the gap, and adjusting the adjustable member until there is no radiation exceeding a predetermined acceptable level at any frequency within the band.
  • Observation of radiation may be effected by a radiation detector outside the klystron or, more simply, by observing the loading on the high frequency source for, obviously, this will be increased when radiation occurs.
  • the aforesaid part of the outersurface of the collector structure may conveniently be part of the outer wall of the cooling water jacket of the collector.
  • the high frequency short. circuit at the outer end of the transmission line is provided by a capacitor including a foil wrapping which is in electrical contact with metal coating on the outer surface of the insulating member of the envelope and extends over
  • the inner metal coating M shown in FIG. 1 on the inner surface of the insulating member 8
  • the length of the transmission line in FIG. 3 is constituted by the radical length of the gap plus the electrical length of the part of the path in the ceramic.
  • the parts of the construction in FIG. 3, which is not adjustable, are, of course, dimensioned to satisfy the requirements of the invention as already set forth.
  • FIGS. 2 and 3 of the accompanying drawings show water-cooled klystrons the invention is, of course, equally applicable to klystrons which are not water-cooled.
  • FIGS. 2 and 3 In view of the detailed description already given of the known construction shown in FIG. 1, the embodiments' of the invention shown in FIGS. 2 and 3 can be -most-easily described by pointing out the respects in which they differ from the construction of FIG. 1.
  • the inner metal coating M which, in FIG. 1, is provided on, the ceramic member 8, is omitted and there is provided a deformable metal cylinder 16 inside and spaced from the inner wall of the said member 8.
  • This cylinder which is such that it can be deformed by I so bent that the transmission line is a half wave length long at the mid-frequency f of the intended working frequency band and is not and does not approximate to an odd number (including unity) of quarter wave lengths long at any frequency within said band or at the secondharmonic of any frequency within said band.
  • the bending of the cylinder 16 is preferably effected with the aid of a high frequency source and probe as altube, said interaction section operating over a selected frequency band, a collector section spaced from said last drift tube to define a gap through which high frequency radiation within said frequency band tends to escape, a sleeve-like insulating member surrounding an end of said collector section and interposed between said sections to preserve evacuated condition within saidfklystron structure, a transmission line having at least a first section defined between said last drift tube and said collector section and leading radially outwardly of said gap and an end section extending parallel to the axis of the klystron structure, and high frequency short circuit means connectedto said end section for providing a high frequency short circuit located externally of said klystron structure, the improvement wherein: said end section of the transmission line is defined by a metallic film in surrounding contiguous relation to said insulating member and a tubular metallic surface within the evacuated interior of said klystron structure, and said metallic surface being spaced to
  • a collector section having a last drift tube defining a gap with said collector section, an insulating sleeve separating said sections and surrounding said gap, and a metallic sleeve member between said insulating sleeve and said collector section;

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  • Microwave Tubes (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
US00405545A 1972-10-11 1973-10-11 Klystrons Expired - Lifetime US3852636A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4675172A GB1398428A (en) 1972-10-11 1972-10-11 Klystrons

Publications (1)

Publication Number Publication Date
US3852636A true US3852636A (en) 1974-12-03

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US00405545A Expired - Lifetime US3852636A (en) 1972-10-11 1973-10-11 Klystrons

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Country Link
US (1) US3852636A (it)
JP (1) JPS5052963A (it)
AU (1) AU471754B2 (it)
CA (1) CA1019836A (it)
DE (1) DE2259321C3 (it)
FR (1) FR2203164A1 (it)
GB (1) GB1398428A (it)
IT (1) IT996804B (it)
NL (1) NL7313935A (it)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3995193A (en) * 1974-04-20 1976-11-30 Nippon Electric Company, Ltd. Microwave tube having structure for preventing the leakage of microwave radiation
US5780969A (en) * 1994-08-05 1998-07-14 Kabushiki Kaisha Toshiba Gyrotron apparatus including reflecting cylinders which provide undesired wave absorption

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3392303A (en) * 1964-08-04 1968-07-09 Varian Associates Microwave tube incorporating a coaxial coupler having water cooling and thermal stress relief
US3392301A (en) * 1964-07-10 1968-07-09 English Electric Valve Co Ltd Klystron having high frequency radiation means comprising a half-wave short-circuited choke
US3436586A (en) * 1965-01-15 1969-04-01 Siemens Ag Frequency modulation tube for the generation or amplification of millimeter waves with a delay line acting as a line resonator
US3448331A (en) * 1966-07-19 1969-06-03 Varian Associates Composite coaxial coupling device and coaxial window
US3500111A (en) * 1966-05-09 1970-03-10 English Electric Valve Co Ltd Microwave electron beam tubes
US3753031A (en) * 1971-05-18 1973-08-14 Thomson Csf Output devices for microwave tubes such as klystrons, and klystrons incorporating such output devices

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3392301A (en) * 1964-07-10 1968-07-09 English Electric Valve Co Ltd Klystron having high frequency radiation means comprising a half-wave short-circuited choke
US3392303A (en) * 1964-08-04 1968-07-09 Varian Associates Microwave tube incorporating a coaxial coupler having water cooling and thermal stress relief
US3436586A (en) * 1965-01-15 1969-04-01 Siemens Ag Frequency modulation tube for the generation or amplification of millimeter waves with a delay line acting as a line resonator
US3500111A (en) * 1966-05-09 1970-03-10 English Electric Valve Co Ltd Microwave electron beam tubes
US3448331A (en) * 1966-07-19 1969-06-03 Varian Associates Composite coaxial coupling device and coaxial window
US3753031A (en) * 1971-05-18 1973-08-14 Thomson Csf Output devices for microwave tubes such as klystrons, and klystrons incorporating such output devices

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3995193A (en) * 1974-04-20 1976-11-30 Nippon Electric Company, Ltd. Microwave tube having structure for preventing the leakage of microwave radiation
US5780969A (en) * 1994-08-05 1998-07-14 Kabushiki Kaisha Toshiba Gyrotron apparatus including reflecting cylinders which provide undesired wave absorption

Also Published As

Publication number Publication date
DE2259321B2 (de) 1975-04-17
CA1019836A (en) 1977-10-25
GB1398428A (en) 1975-06-18
DE2259321A1 (de) 1974-04-18
DE2259321C3 (de) 1975-11-27
AU6122773A (en) 1975-04-10
JPS5052963A (it) 1975-05-10
FR2203164A1 (it) 1974-05-10
AU471754B2 (en) 1976-04-29
IT996804B (it) 1975-12-10
NL7313935A (it) 1974-04-16

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