WO1996035219A1 - Canon a electrons a grille - Google Patents
Canon a electrons a grille Download PDFInfo
- Publication number
- WO1996035219A1 WO1996035219A1 PCT/FR1996/000644 FR9600644W WO9635219A1 WO 1996035219 A1 WO1996035219 A1 WO 1996035219A1 FR 9600644 W FR9600644 W FR 9600644W WO 9635219 A1 WO9635219 A1 WO 9635219A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- grid
- cathode
- electron gun
- gun according
- recess
- Prior art date
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
- H01J25/04—Tubes having one or more resonators, without reflection of the electron stream, and in which the modulation produced in the modulator zone is mainly density modulation, e.g. Heaff tube
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/13—Solid thermionic cathodes
- H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
-
- 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
- H01J23/06—Electron or ion guns
- H01J23/07—Electron or ion guns producing a hollow cylindrical beam
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J3/00—Details of electron-optical or ion-optical arrangements or of ion traps common to two or more basic types of discharge tubes or lamps
- H01J3/02—Electron guns
- H01J3/027—Construction of the gun or parts thereof
Definitions
- the field of the invention is that of electronic tubes and in particular those with longitudinal electron beams with a grid such as IOT (abbreviation of the English terms Inductive Output Tube).
- An IOT comprises an electron gun which emits an electron beam, a resonant cavity which is crossed by the beam and a collector which collects the electrons of the beam at their exit from the cavity.
- the electron gun has a generally concave cathode in the shape of a portion of a sphere, a control grid and an anode.
- the concave face of the cathode emits electrons when it is brought to high temperature.
- the electrons pass through the control grid and are attracted to the anode then enter the resonant cavity by forming a longitudinal beam.
- the control grid is used to modulate the emission of electrons so as to group them into packets before they enter the resonant cavity.
- the cathode is generally produced by a porous body impregnated with an emissive material.
- the porous body can be made of tungsten and the emissive material of barium, calcium and strontium aluminates. It begins to emit electrons around 900 ° to 1100 ° C.
- the control grid is very close to the cathode.
- the interval between the grid and the cathode is of the order of a few tenths of a millimeter.
- the emissive material tends to evaporate and migrate, in particular on the control grid and on the anode.
- the grid heats up, on the one hand because of the proximity of the cathode, and on the other hand because of the electrons which strike it.
- the emissive material which has migrated on the grid causes a parasitic emission of electrons which disturbs the operation of the tube.
- the anode being relatively far from the cathode, it remains relatively cold and the emissive material which covers it is not too troublesome.
- Another route followed to avoid this parasitic emission of electrons consists in reducing the temperature of the grid as much as possible during the operation of the tube.
- a known solution is to use a cathode working at lower temperatures than those of conventional cathodes to thereby lower the temperature of the control grid. This solution also does not give good results.
- the parasitic emission phenomenon is only delayed but not eliminated.
- the present invention aims to remedy these drawbacks by proposing an electron gun whose cathode contributes to better cooling of the grid and makes it possible to effectively avoid parasitic emission.
- This cathode has an emissive part which delimits a substantially central recess which crosses it right through.
- the cathode is advantageously heated by a heating device which comprises a heating element opposite its emissive part, this heating element delimiting a recess facing the recess of the cathode.
- the grid has a thermally radiating solid part, intended to be placed facing the recess of the cathode.
- the heat dissipation of the grid by radiation is improved thanks to this solid part, radiating thermally, because it can radiate towards the recess of the cathode and towards the anode zone which is a cold zone.
- the grid being better cooled the emission of parasitic electrons is eliminated. It is preferable to produce the solid part in a material having a thermal radiation capacity close to that of the black body. Pyrolitic graphite is particularly advantageous.
- the present invention also relates to an electronic tube comprising such a gun.
- FIG. 2a, 2b respectively a front view and a cross section of an example of a cathode of a barrel according to the invention
- FIG. 3 a front view of an example of a grid of a barrel according to the invention
- FIG. 4 a schematic longitudinal section of an example of an electron gun according to the invention mounted in an electronic tube also according to the invention;
- FIG. 5 a front view of a device for heating the cathode of the barrel according to the invention.
- the same references designate the same elements. For reasons of clarity, the dimensions of the various elements are not respected.
- FIG 1a shows in longitudinal section a known electron gun.
- the cathode bears the reference 1. It is full and in the form of a portion of a sphere, its active face is concave.
- a heating device 2 is in contact with the cathode 1 opposite its active face.
- the electrons emitted by the active face of the cathode 1 pass through a control grid 3 and are attracted by an anode 4. They form a longitudinal beam of axis XX '.
- the anode 4 has a central opening 5 for letting the electron beam enter a resonant cavity (not shown).
- the anode 4 is brought to a more positive potential than the cathode 1.
- the grid 3 is generally brought to a potential intermediate between that of the cathode 1 and that of the anode 4.
- the grid 3 is mounted on a peripheral support 6 made of a material which is a good thermal conductor such as copper. It is also in the form of a portion of a sphere with first bars 7 arranged on parallels of the sphere and second bars 8 arranged on meridians of the sphere. The two portions of the sphere, that is to say that of the cathode 1 and that of the grid 3, have their center on the axis XX '.
- Figure 1b shows the front view of the grid.
- the cathode 1 heats the emissive material evaporates and it will cover in particular the grid 3.
- the cooling of the grid 3 takes place on the one hand by conduction towards the peripheral support 6 via the first and second bars 7, 8, and on the other hand by radiation towards the anode 4 essentially.
- the hottest part of the grid 3 is its central part. Any increase in the size of the cathode 1 leads to an increase in the size of the grid 3 and therefore the temperature of its central part. To avoid increasing parasitic remission of the grid 3, one is forced to limit the size of the cathode 1 and consequently the electronic current which it supplies.
- FIGS 2a and 2b show from the front and in longitudinal section an example of a cathode 10 of a gun according to the invention.
- the cathode is a portion of a sphere. It comprises an emissive part 12 which defines a substantially central recess 11.
- the emissive part 12 is concave and substantially in the form of a segment of a sphere and the recess 11 is substantially circular.
- the emissive surface of a cathode such as that of FIG. 1a varies in the first order as the square of its diameter.
- the diameter of the recess 11 represents approximately 30 to 40% of the diameter of the cathode 10
- the surface of the recess 11 is relatively small and has no practically no influence on the electronic emission. The small loss of emissive surface can be compensated by a small increase in the diameter of the cathode 10.
- FIG. 3 represents the drawing of a grid of a cannon according to the invention. This grid is intended to be associated with a cathode of the type shown in FIGS. 2a and 2b.
- the grid has a solid thermally radiating part 24 intended to be placed facing the recess of the cathode.
- the grid When the grid is mounted in an electron gun with such an electron-emitting cathode, it can radiate on the one hand towards the anode and on the other hand towards the recess of the cathode.
- This grid is effectively cooled and the stray electron emission is eliminated.
- the diameter of the cathode is dissociated from the temperature of the grid and we can consider designing more powerful electronic tubes with this type of gun.
- the solid part 24 of the grid 23 is made of a material having a thermal radiation capacity close to that of the black body.
- Graphite and more particularly pyrolitic graphite is a material which is particularly well suited for producing this solid part 24 radiating thermally.
- the grid shown in FIG. 3 comprises around the solid part 24 an openwork part 26 which is intended to be crossed by the electrons emitted by the cathode.
- the perforated part 26 may also be made of pyrolitic graphite because of its advantageous thermal, electrical and mechanical properties.
- the grid 23 is intended to be used with a cathode substantially in the form of a portion of a sphere, it is preferable that it also be substantially in the form of a portion of the sphere.
- the solid part 24 may be in the form of a spherical cap and the perforated part 26 may include first bars 28 arranged along meridians of the sphere and second bars 29 along parallels of the sphere.
- the grid 23 can be produced from a blank in pyrolitic graphite, for example in the form of a portion of a sphere, in which the bars 28, 29 and the solid part are cut. This size can be produced in a conventional manner, by for example by laser machining or by sandblasting. It could also be envisaged that the perforated part 26 of the grid has substantially rectangular or hexagonal openings.
- FIG. 4 shows in longitudinal section, an example of an electron gun according to the invention mounted in an electronic tube also according to the invention.
- the barrel comprises a cathode 21 according to the invention and a control grid 23 both substantially in the form of a portion of a sphere.
- the cathode 21 has an emissive part 27 in the form of a segment of a sphere which defines a substantially central recess 22.
- An anode 25 and a heater 40 for the cathode have also been shown in this figure.
- the electronic tube is partially shown. It includes the electron gun and the emitted electrons are finally recovered from the race in a collector 43.
- the grid 23 associated with the cathode according to the invention has a solid part 24. It is comparable to that of Figure 3. Its heat dissipation is better than in the barrel of Figure 1 a.
- the heat dissipation is even better.
- the bars 28, 29 of the grid are cooled by conduction, both towards the peripheral support 30 and towards the solid part 24 radiating thermally.
- the solid part 24 is cooled by radiation towards the anode 25 and towards the recess 22 of the cathode 21.
- the length of the first bars 28 is considerably reduced compared to that of the bars of FIG. 1b. For example, their length can go from approximately 41 millimeters to approximately 14.5 millimeters in the example cited above.
- the solid part 24 of the grid 23 will have substantially the same size as the recess 22 of the cathode 21.
- the cathode according to the invention is associated with a grid without a solid part, that is to say a traditional grid like that of FIG. 1b, for example. If this grid is made of a material having a radiation capacity close to that of the black body, the part of the grid facing the recess of the cathode can radiate towards this recess.
- the cooling of the central part of the grid is improved compared to that of a grid as shown in FIG. 1a and associated with a solid cathode but it is not as good as in the case of FIG. 4. However in certain cases , this cooling is quite sufficient.
- the cathode must be heated to be able to emit electrons.
- a device 40 for indirect heating of the cathode has been shown in FIG. 4. It is seen from the front in FIG. 5. It is provided for heating the emissive part 27 of the cathode 21. It is arranged near the convex face. of cathode 21. It includes a heating element 42 defining a recess 41 facing the recess 22 of the cathode 21. It may be in the form of a perforated plate defining a network of conductors 45 in which an electric current can flow. This plate will be produced, preferably in an electrically conductive material, having a thermal radiation capacity close to that of the black body. Pyrolitic graphite is particularly suitable for producing the heating element 42.
- the plate comprises a series of slots 44 in a concentric arc of a circle, the slots 44 placed on two successive circles being offset one by the other. compared to others.
- the space between the slots 44 forms the network of electrical conductors 42.
- the barrel according to the invention is not limited to a cathode in portion of sphere, nor to a grid in portion of sphere.
Landscapes
- Microwave Tubes (AREA)
- Electron Sources, Ion Sources (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP53306796A JP4019431B2 (ja) | 1995-05-05 | 1996-04-26 | グリッドを有する電子銃 |
DE69614520T DE69614520T2 (de) | 1995-05-05 | 1996-04-26 | Eletronenkanone mit gitter |
US08/945,675 US5936335A (en) | 1995-05-05 | 1996-04-26 | Electron gun having a grid |
EP96914252A EP0824758B1 (fr) | 1995-05-05 | 1996-04-26 | Canon a electrons a grille |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9505408A FR2733856B1 (fr) | 1995-05-05 | 1995-05-05 | Cathode pour canon a electrons a grille, grille destinee a etre associee avec une telle cathode et canon a electrons comportant une telle cathode |
FR95/05408 | 1995-05-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996035219A1 true WO1996035219A1 (fr) | 1996-11-07 |
Family
ID=9478747
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR1996/000644 WO1996035219A1 (fr) | 1995-05-05 | 1996-04-26 | Canon a electrons a grille |
Country Status (7)
Country | Link |
---|---|
US (1) | US5936335A (fr) |
EP (1) | EP0824758B1 (fr) |
JP (1) | JP4019431B2 (fr) |
CN (1) | CN1099689C (fr) |
DE (1) | DE69614520T2 (fr) |
FR (1) | FR2733856B1 (fr) |
WO (1) | WO1996035219A1 (fr) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2326273A (en) * | 1997-06-13 | 1998-12-16 | Eev Ltd | Grids for electron beam tubes |
EP1091386B1 (fr) * | 1999-10-07 | 2012-11-21 | Lucent Technologies Inc. | Dispositif d'illumination pour appareil de lithographie par faisceau d'électrons |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2775118B1 (fr) | 1998-02-13 | 2000-05-05 | Thomson Tubes Electroniques | Grille pour tube electronique a faisceau axial a performances ameliorees |
FR2789800B1 (fr) | 1999-02-16 | 2001-05-11 | Thomson Tubes Electroniques | Generateur radiofrequence de tres grande puissance |
GB9915925D0 (en) * | 1999-07-08 | 1999-09-08 | Univ Loughborough | Flow field plates |
US6528799B1 (en) * | 2000-10-20 | 2003-03-04 | Lucent Technologies, Inc. | Device and method for suppressing space charge induced aberrations in charged-particle projection lithography systems |
FR2853450B1 (fr) * | 2003-04-04 | 2006-09-08 | Thales Sa | Grille de commande d'un tube electronique |
JP4113032B2 (ja) * | 2003-04-21 | 2008-07-02 | キヤノン株式会社 | 電子銃及び電子ビーム露光装置 |
JP5148582B2 (ja) | 2009-10-20 | 2013-02-20 | 株式会社エー・アンド・デイ | 圧力を利用したリークテスター |
CN105414732B (zh) * | 2015-12-23 | 2018-06-29 | 哈尔滨工业大学(威海) | 多阴极电子枪装置 |
CN106216788B (zh) * | 2016-08-23 | 2019-07-02 | 安徽华东光电技术研究所 | 一种电子控制栅网焊接工装的焊接方法 |
CN115699241A (zh) * | 2020-06-15 | 2023-02-03 | 上海联影医疗科技股份有限公司 | 电子枪 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR960750A (fr) * | 1950-04-22 | |||
US2936393A (en) * | 1956-12-28 | 1960-05-10 | Hughes Aircraft Co | Low noise traveling-wave tube |
US2985789A (en) * | 1960-02-17 | 1961-05-23 | Bell Telephone Labor Inc | Low-noise electron gun |
DE1212227B (de) * | 1961-12-13 | 1966-03-10 | Deutsche Bundespost | Flaechenkathode fuer Elektronenstrahlroehren |
DE2214660A1 (de) * | 1971-04-12 | 1973-12-06 | Werk Fernsehelektronik Veb | Katode fuer laufzeitroehren |
EP0578525A1 (fr) * | 1992-06-26 | 1994-01-12 | Thomson Tubes Electroniques | Canon à électrons à échauffement réduit de la grille |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1523248A (fr) * | 1967-03-07 | 1968-05-03 | Thomson Houston Comp Francaise | Perfectionnements aux procédés de fabrication d'électrodes en forme de grilles pour tubes électroniques, électrodes fabriquées à l'aide de ces procédés perfectionnés et tubes électroniques contenant de telles électrodes |
FR2445605A1 (fr) * | 1978-12-27 | 1980-07-25 | Thomson Csf | Cathode a chauffage direct et tube electronique haute frequence comportant une telle cathode |
FR2498372A1 (fr) * | 1981-01-16 | 1982-07-23 | Thomson Csf | Cathode a chauffage direct, son procede de fabrication, et tube electronique incorporant une telle cathode |
FR2532468A1 (fr) * | 1982-08-31 | 1984-03-02 | Thomson Csf | Perfectionnement aux cathodes a chauffage direct |
US4583021A (en) * | 1983-04-18 | 1986-04-15 | Litton Systems, Inc. | Electron gun with improved cathode and shadow grid configuration |
US4553064A (en) * | 1983-08-30 | 1985-11-12 | Hughes Aircraft Company | Dual-mode electron gun with improved shadow grid arrangement |
US4737680A (en) * | 1986-04-10 | 1988-04-12 | Litton Systems, Inc. | Gridded electron gun |
US4745326A (en) * | 1986-12-10 | 1988-05-17 | The United States Of America As Represented By The Secretary Of The Navy | Method of manufacturing integral shadow gridded controlled porosity, dispenser cathodes |
FR2728386B1 (fr) * | 1994-12-20 | 1997-01-24 | Thomson Tubes Electroniques | Tube electronique a grille a performances ameliorees |
-
1995
- 1995-05-05 FR FR9505408A patent/FR2733856B1/fr not_active Expired - Fee Related
-
1996
- 1996-04-26 WO PCT/FR1996/000644 patent/WO1996035219A1/fr active IP Right Grant
- 1996-04-26 EP EP96914252A patent/EP0824758B1/fr not_active Expired - Lifetime
- 1996-04-26 DE DE69614520T patent/DE69614520T2/de not_active Expired - Lifetime
- 1996-04-26 JP JP53306796A patent/JP4019431B2/ja not_active Expired - Fee Related
- 1996-04-26 CN CN96193728A patent/CN1099689C/zh not_active Expired - Fee Related
- 1996-04-26 US US08/945,675 patent/US5936335A/en not_active Expired - Lifetime
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR960750A (fr) * | 1950-04-22 | |||
US2936393A (en) * | 1956-12-28 | 1960-05-10 | Hughes Aircraft Co | Low noise traveling-wave tube |
US2985789A (en) * | 1960-02-17 | 1961-05-23 | Bell Telephone Labor Inc | Low-noise electron gun |
DE1212227B (de) * | 1961-12-13 | 1966-03-10 | Deutsche Bundespost | Flaechenkathode fuer Elektronenstrahlroehren |
DE2214660A1 (de) * | 1971-04-12 | 1973-12-06 | Werk Fernsehelektronik Veb | Katode fuer laufzeitroehren |
EP0578525A1 (fr) * | 1992-06-26 | 1994-01-12 | Thomson Tubes Electroniques | Canon à électrons à échauffement réduit de la grille |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2326273A (en) * | 1997-06-13 | 1998-12-16 | Eev Ltd | Grids for electron beam tubes |
EP0884751A1 (fr) * | 1997-06-13 | 1998-12-16 | Eev Limited | Grilles |
EP0884752A1 (fr) * | 1997-06-13 | 1998-12-16 | Eev Limited | Grilles |
EP1091386B1 (fr) * | 1999-10-07 | 2012-11-21 | Lucent Technologies Inc. | Dispositif d'illumination pour appareil de lithographie par faisceau d'électrons |
Also Published As
Publication number | Publication date |
---|---|
US5936335A (en) | 1999-08-10 |
DE69614520D1 (de) | 2001-09-20 |
CN1183852A (zh) | 1998-06-03 |
CN1099689C (zh) | 2003-01-22 |
FR2733856B1 (fr) | 1997-08-29 |
EP0824758A1 (fr) | 1998-02-25 |
JP4019431B2 (ja) | 2007-12-12 |
EP0824758B1 (fr) | 2001-08-16 |
DE69614520T2 (de) | 2002-05-08 |
FR2733856A1 (fr) | 1996-11-08 |
JPH11505059A (ja) | 1999-05-11 |
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