GB2293043A - Cavity arrangements for electron beam tubes - Google Patents
Cavity arrangements for electron beam tubes Download PDFInfo
- Publication number
- GB2293043A GB2293043A GB9516775A GB9516775A GB2293043A GB 2293043 A GB2293043 A GB 2293043A GB 9516775 A GB9516775 A GB 9516775A GB 9516775 A GB9516775 A GB 9516775A GB 2293043 A GB2293043 A GB 2293043A
- Authority
- GB
- United Kingdom
- Prior art keywords
- arrangement
- cavity
- tube
- electron beam
- magnetic material
- 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.)
- Granted
Links
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
-
- 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
- H01J23/08—Focusing arrangements, e.g. for concentrating stream of electrons, for preventing spreading of stream
- H01J23/087—Magnetic focusing arrangements
- H01J23/0876—Magnetic focusing arrangements with arrangements improving the linearity and homogeniety of the axial field, e.g. field straightener
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2223/00—Details of transit-time tubes of the types covered by group H01J2225/00
- H01J2223/16—Circuit elements, having distributed capacitance and inductance, structurally associated with the tube and interacting with the discharge
- H01J2223/18—Resonators
- H01J2223/20—Cavity resonators; Adjustment or tuning thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2223/00—Details of transit-time tubes of the types covered by group H01J2225/00
- H01J2223/36—Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy
- H01J2223/40—Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy to or from the interaction circuit
Landscapes
- Microwave Tubes (AREA)
Abstract
In a cavity, e.g. an output resonant cavity 7, used with a linear electron beam tube such as an IOT, magnetic material 17 and 23 is mounted on at least one of the walls 12 and 13 through which the tube extends. The material 17 and 23, together with coils 21, 22 and 27, focus an electron beam travelling along the axis X-X of a tube located in the apertures 15 and 16. An inner rim 28 locates the electron beam tube in relation to the cavity. <IMAGE>
Description
Cavity Arrangements This invention relates to cavity arrangements and more particularly to arrangements for use with linear electron beam tubes.
A linear electron beam tube is a device, such as a klystron or an inductive output tube (IOT), in which an electron beam is generated to travel along a linear path and interact with high frequency energy at resonant cavities. In an IOT, for example, an annular input resonant cavity surrounds an electron gun and is arranged such that high frequency energy
coupled into the cavity generates a modulating signal between the cathode and grid of the
electron gun, hence density modulating the electron beam. After transmission along a drift
tube, an amplified high frequency signal is coupled from an output resonant cavity located
further along the electron beam path.
According to the present invention there is provided a cavity arrangement for use
with a linear electron beam tube comprising: a resonant cavity having two walls with
apertures therein through which in use the tube is extensive; and magnetic focusing means
including magnetic material mounted on the outer surface of at least one of the two walls.
Magnetic focusing means is used with linear beam tubes to counteract the repulsion
of electrons in the beam due to space charge effects and hence prevent impact of electrons on
the parts of the tube surrounding the electron beam path.
By mounting magnetic material on the outer surface of the resonant cavity wall or walls, a more compact overall arrangement is provided compared to a conventional arrangement in which the magnetic focusing means is provided by completely separate items.
The integration of the magnetic material with the cavity also facilitates assembly of the complete device as these components may be accurately aligned relative to one another and securely fixed together prior to combining them with the electron beam tube. Also, the number of components in the complete device is reduced, improving ease of handling and installation. The magnetic material may be mounted on the surface of the wall by a suitable glue or other fixing mechanism. The magnetic material is located outside the vacuum envelope of the electron beam tube and is separately mounted from the tube, giving good accessibility for servicing and the like.
The magnetic material may be carried on one wall only but in one embodiment of the invention magnetic material is carried on the outer surfaces of both cavity walls.
Preferably, the magnetic focusing means includes electromagnetic coil means. The coil means may be wound on the magnetic material or may formed separately and positioned adjacent the magnetic material. In other alternative embodiments of the invention, the magnetic focusing means includes permanent magnetic material.
Where coil means is included, preferably, the magnetic material comprises a member hay inc a first portion parallel to the wall surface and attached thereto and a second portion substantiall! normal to the surface. The magnetic member may also include a third portion substanti; parallel to the surface and spaced therefrom to define an annular channel between it and the surface, and preferably coil means is located in the channel. In one embodiment of the invention, the magnetic member comprises a cylindrical wall having at an inwardly extensive flange which is secured to the cavity wall and at its other end an outwardly extensive flange.
Advantageously, the magnetic material includes an inner projection extensive inside the aperture diameter which in use may be engaged with the electron beam tube to accurately locate it relative to the cavity and the focusing means.
According to a feature of the invention, a tube assembly comprises a cavity arrangement in accordance with the invention and a linear electron beam tube, which advantageously is an inductive output tube.
One way in which the invention may be performed is now described by way of example with reference to the accompanying drawings in which:
Figure 1 is a schematic representation of an IOT assembly including a cavity arrangement in accordance with the invention; and
Figure 2 shows schematically and in greater detail part of the assembly illustrated in
Figure 1.
with reference to Figure 1. an IOT includes an electron gun 1 comprising a cathode 2 and grid 3 about which is located an annular resonant cavity 4 having a coupling loop 5 via which a high frequency signal may be coupled into the cavity 4. The electron beam produced by the gun 1 is arranged to travel along the longitudinal axis X-X of the tube through a drift region to a drift tube gap 6 which is surrounded by a output resonant cavity 7.
An amplified high frequency output signal is coupled from cavity 7 into a secondary output cavity 8 via coupling means 9 and thence via coupling means 10 externally from the arrangement. A collector 11 is arranged to receive electrons of the beam after they have passed through the interaction region 6.
With reference to Figure 2, the output cavity 7 comprises two walls 12 and 13 substantially normal to the axis X-X and a wall 14 which joins them. The transverse walls 12 and 13 have apertures 15 and 16 respectively therethrough through which in use the tube is extensive. Magnetic material 17 is located on the outer surface of cavity wall 12 and includes a cylindrical wall portion 18 extending parallel to the axis X-X and having an inwardly extensive portion 19 substantially parallel to the outer surface of the wall 12 and mounted thereon. It also includes an outwardly extensive flange 20 spaced from the wall 12 and substantially parallel thereto. Coils 21 and 22 are located in the annular channel defined by the flange 20, cylinder 18 and wall 12.
A second member 23 of magnetic material is fixed to the other transverse wall 13 and also includes cylindrical wall portion 24 and inner and outer flanges 25 and 26. A coil 27 is located in the channel defined by the magnetic material 23 and the wall 13. The member 24 includes an inwardly projecting rim 28 extending inside the outer diameter of the aperture 16 and defining a ledge which locates the electron beam tube in the complete assembly relative to the output cavity 7 and the focusing means carried by it the tube having a reduced diameter which engages with the rim 28.
The cavities 7 and 8 are external cavities located outside the vacuum envelope. The magnetic material is also positioned outside the vacuum envelope.
Claims (13)
1. A cavity arrangement for use with a linear electron beam tube comprising: a resonant cavity having two walls with apertures therein through which in use the tube is extensive; and magnetic focusing means including magnetic material mounted on the outer surface of at least one of the two walls.
2. An arrangement as claimed in claim 1 wherein the magnetic focusing means includes electromagnetic coil means.
3. An arrangement as claimed in claim 2 wherein the coil means is wound on the magnetic material.
4. An arrangement as claimed in claim 1, 2 or 3 wherein the magnetic material comprises a member having a first portion substantially parallel to the outer surface and attached thereto and second portion substantially normal to the outer surface.
5. An arrangement as claimed in claim 4 wherein the member includes a third portion substantially parallel to the outer surface and spaced therefrom to define an annular channel between it and the outer surface.
6. An arrangement as claimed in claim 5 wherein coil means is located in the annular channel.
7. An arrangement as claimed in any preceding claim wherein the magnetic material is arranged around an aperture in one of the walls and includes a projection projecting inside the diameter of the aperture.
8. An arrangement as claimed in claim 7 wherein the projection in use is engagable with the tube to locate it in the aperture relative to the cavity and focusing means
9. An arrangement as claimed in any preceding claim wherein the resonant cavity is an output cavity and includes coupling means for coupling energy therefrom.
10. A tube assembly comprising a cavity arrangement as claimed in any preceding claim and a linear electron beam tube.
11. An assembly as claimed in claim 10 wherein the tube is an inductive output tube.
12. A cavity arrangement substantially as illustrated in and described in respect to Figure 2 of the accompanying drawings.
13. A tube assembly substantially as illustrated in and described with reference to Figures 1 and 2 of the accompanying drawings.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9516775A GB2293043B (en) | 1994-09-07 | 1995-08-16 | Cavity arrangements |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9418028A GB9418028D0 (en) | 1994-09-07 | 1994-09-07 | Cavity arrangements |
GB9516775A GB2293043B (en) | 1994-09-07 | 1995-08-16 | Cavity arrangements |
Publications (3)
Publication Number | Publication Date |
---|---|
GB9516775D0 GB9516775D0 (en) | 1995-10-18 |
GB2293043A true GB2293043A (en) | 1996-03-13 |
GB2293043B GB2293043B (en) | 1998-05-06 |
Family
ID=26305580
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9516775A Expired - Fee Related GB2293043B (en) | 1994-09-07 | 1995-08-16 | Cavity arrangements |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2293043B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2935534A1 (en) * | 2008-08-29 | 2010-03-05 | Thales Sa | Resonant cavities coupling device for e.g. triode, in TV for scientific application, has loop traversing iris situated in wall common to cavities, and including tube in which coolant circulates, where coolant is used for cooling loop |
CN111785598A (en) * | 2020-07-23 | 2020-10-16 | 中国舰船研究设计中心 | Distributed output resonant cavity with gradually-changed gap width |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB946020A (en) * | 1962-05-18 | 1964-01-08 | Standard Telephones Cables Ltd | Improvements in or relating to travelling wave tubes |
GB1189640A (en) * | 1966-12-09 | 1970-04-29 | Philips Electronic Associated | Klystron. |
US4558258A (en) * | 1982-04-26 | 1985-12-10 | Tokyo Shibaura Denki Kabushiki Kaisha | Klystron unit |
-
1995
- 1995-08-16 GB GB9516775A patent/GB2293043B/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB946020A (en) * | 1962-05-18 | 1964-01-08 | Standard Telephones Cables Ltd | Improvements in or relating to travelling wave tubes |
GB1189640A (en) * | 1966-12-09 | 1970-04-29 | Philips Electronic Associated | Klystron. |
US4558258A (en) * | 1982-04-26 | 1985-12-10 | Tokyo Shibaura Denki Kabushiki Kaisha | Klystron unit |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2935534A1 (en) * | 2008-08-29 | 2010-03-05 | Thales Sa | Resonant cavities coupling device for e.g. triode, in TV for scientific application, has loop traversing iris situated in wall common to cavities, and including tube in which coolant circulates, where coolant is used for cooling loop |
CN111785598A (en) * | 2020-07-23 | 2020-10-16 | 中国舰船研究设计中心 | Distributed output resonant cavity with gradually-changed gap width |
CN111785598B (en) * | 2020-07-23 | 2023-08-08 | 中国舰船研究设计中心 | Distributed output resonant cavity with gradually changed gap width |
Also Published As
Publication number | Publication date |
---|---|
GB2293043B (en) | 1998-05-06 |
GB9516775D0 (en) | 1995-10-18 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20010816 |