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EP0824758A1 - Grid electron gun - Google Patents

Grid electron gun

Info

Publication number
EP0824758A1
EP0824758A1 EP96914252A EP96914252A EP0824758A1 EP 0824758 A1 EP0824758 A1 EP 0824758A1 EP 96914252 A EP96914252 A EP 96914252A EP 96914252 A EP96914252 A EP 96914252A EP 0824758 A1 EP0824758 A1 EP 0824758A1
Authority
EP
European Patent Office
Prior art keywords
grid
cathode
electron gun
gun according
recess
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
Application number
EP96914252A
Other languages
German (de)
French (fr)
Other versions
EP0824758B1 (en
Inventor
Guy Thomson-CSF SCPI CLERC
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 Electron Devices SA
Original Assignee
Thomson Tubes Electroniques
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 Thomson Tubes Electroniques filed Critical Thomson Tubes Electroniques
Publication of EP0824758A1 publication Critical patent/EP0824758A1/en
Application granted granted Critical
Publication of EP0824758B1 publication Critical patent/EP0824758B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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.

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  • Microwave Tubes (AREA)
  • Electron Sources, Ion Sources (AREA)

Abstract

The present invention relates to a grid electron tube whose cathode is comprised of an emissive part (12) which delimits a substantially central recess (11). Said cathode reduces considerably the emission of spurious electrons of the grid by contributing to its cooling. Application particularly to electronic tubes known as IOT.

Description

CANON A ELECTRONS A GRILLE GRID ELECTRON CANON
Le domaine de l'invention est celui des tubes électroniques et notamment ceux à faisceaux d'électrons longitudinaux à grille tels que les IOT (abréviation des termes anglais Inductive Output Tube).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).
Un IOT comporte un canon à électrons qui émet un faisceau d'électrons, une cavité résonante qui est traversée par le faisceau et un collecteur qui recueille les électrons du faisceau à leur sortie de la cavité.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.
Le canon à électrons comporte une cathode généralement concave et en forme de portion de sphère, une grille de commande et une anode. La face concave de la cathode émet des électrons lorsqu'elle est portée à haute température. Les électrons traversent la grille de commande et sont attirés par l'anode puis pénètrent dans la cavité résonante en formant un faisceau longitudinal. La grille de commande sert à moduler l'émission d'électrons de manière à les regrouper en paquets avant leur entrée dans la cavité résonante.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.
La cathode est généralement réalisée par un corps poreux imprégné d'un matériau émissif. Le corps poreux peut être en tungstène et le matériau émissif des aluminates de baryum, de calcium et de strontium. Elle commence à émettre des électrons aux alentours de 900° à 1100° C.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.
La grille de commande est très proche de la cathode. L'intervalle entre la grille et la cathode est de l'ordre de quelques dixièmes de millimètres. Le matériau émissif à tendance à s'évaporer et à migrer notamment sur la grille de commande et sur l'anode. La grille chauffe, d'une part à cause de la proximité de la cathode, et d'autre part à cause des électrons qui la percutent. Le matériau émissif qui a migré sur la grille provoque une émission d'électrons parasite qui perturbe le fonctionnement du tube. L'anode étant relativement éloignée de la cathode, elle reste relativement froide et le matériau émissif qui la recouvre n'est pas trop gênant.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.
Des solutions ont été proposées pour éliminer cette émission d'électrons parasite. L'une d'elle préconise de bombarder la grille avec des électrons pour la chauffer et pour faire évaporer le matériau émissif qui la recouvre. La fréquence de ce chauffage peut être journalière, avant chaque mise en route par exemple. Le nettoyage de la grille par chauffage est une contrainte sévère sur un émetteur de télévision qui peut fonctionner sur un site isolé avec un pilotage à distance. Ce chauffage peut aussi provoquer à la longue une dégradation du fonctionnement du canon à électrons.Solutions have been proposed to eliminate this parasitic electron emission. One of them recommends bombarding the grid with electrons to heat it and to evaporate the emissive material that covers it. The frequency of this heating can be daily, before each start-up for example. Cleaning the grid by heating is a severe constraint on a television transmitter which can function on an isolated site with a remote piloting. This heating can also cause in the long term a degradation of the operation of the electron gun.
Une autre voie suivie pour éviter cette émission d'électrons parasite consiste à diminuer autant que possible la température de la grille pendant le fonctionnement du tube. Une solution connue est d'utiliser une cathode travaillant à des températures plus basses que celles des cathodes classiques pour abaisser de ce fait la température de la grille de commande. Cette solution ne donne pas non plus de bons résultats. Le phénomène d'émission parasite est seulement retardé mais pas éliminé.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.
Un autre inconvénient rencontré est que l'émission parasite de la grille de commande limite la taille de la cathode et par conséquent le courant électronique produit.Another drawback encountered is that the spurious emission from the control gate limits the size of the cathode and consequently the electronic current produced.
La présente invention vise à remédier à ces inconvénients en proposant un canon à électrons dont la cathode contribue à un meilleur refroidissement de la grille et permet d'éviter efficacement l'émission parasite.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.
Cette cathode comporte une partie emissive qui délimite un évidement sensiblement central qui la traverse de part en part. La cathode est de manière avantageuse chauffée par un dispositif de chauffage qui comporte un élément chauffant à l'opposé de sa partie emissive, cet élément chauffant délimitant un évidement face à l'evidement de la cathode.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.
La grille comporte une partie pleine rayonnant thermiquement, destinée à être disposée face à l'evidement de la cathode. La dissipation thermique de la grille par rayonnement est améliorée grâce à cette partie pleine, rayonnant thermiquement, car elle peut rayonner vers l'evidement de la cathode et vers la zone anodique qui est une zone froide. La grille étant mieux refroidie l'émission d'électrons parasite est éliminée. II est préférable de réaliser la partie pleine dans un matériau ayant une capacité de rayonnement thermique proche de celle du corps noir. Le graphite pyrolitique est particulièrement avantageux.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.
La présente invention concerne aussi un tube électronique comportant un tel canon. D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description ci-dessous illustrée par les figures annexées qui représentent:The present invention also relates to an electronic tube comprising such a gun. Other characteristics and advantages of the invention will appear on reading the description below illustrated by the appended figures which represent:
- les figures 1a, 1b respectivement une coupe longitudinale d'un canon à électrons de l'art antérieur et une vue de face de sa grille;- Figures 1a, 1b respectively a longitudinal section of an electron gun of the prior art and a front view of its grid;
- les figures 2a, 2b respectivement une vue de face et une coupe transversale d'un exemple d'une cathode d'un canon conforme à l'invention;- Figures 2a, 2b respectively a front view and a cross section of an example of a cathode of a barrel according to the invention;
- la figure 3 une vue de face d'un exemple d'une grille d'un canon conforme à l'invention; - la figure 4 une coupe schématique longitudinale d'un exemple d'un canon à électrons conforme à l'invention monté dans un tube électronique également conforme à l'invention;- Figure 3 a front view of an example of a grid of a barrel according to the invention; - Figure 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;
- la figure 5 une vue de face d'un dispositif pour chauffer la cathode du canon selon l'invention. Sur ces figures, les mêmes références désignent les mêmes éléments. Pour des raisons de clarté les côtes des différents éléments ne sont pas respectées.- Figure 5 a front view of a device for heating the cathode of the barrel according to the invention. In these figures, the same references designate the same elements. For reasons of clarity, the dimensions of the various elements are not respected.
La figure 1 a montre en coupe longitudinale un canon à électrons connu. La cathode porte la référence 1. Elle est pleine et en forme de portion de sphère, sa face active est concave. Un dispositif de chauffage 2 est en contact avec la cathode 1 à l'opposé de sa face active. Les électrons émis par la face active de la cathode 1 traversent une grille 3 de commande et sont attirés par une anode 4. Ils forment un faisceau longitudinal d'axe XX'. L'anode 4 comporte une ouverture centrale 5 pour laisser le faisceau d'électrons pénétrer dans une cavité résonante (non représentée). L'anode 4 est portée à un potentiel plus positif que la cathode 1. La grille 3 est généralement portée à un potentiel intermédiaire entre celui de la cathode 1 et celui de l'anode 4.Figure 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.
La grille 3 est montée sur un support périphérique 6 réalisé dans un matériau bon conducteur thermique tel que le cuivre. Elle est aussi en forme de portion de sphère avec des premiers barreaux 7 disposés sur des parallèles de la sphère et des seconds barreaux 8 disposés sur des méridiens de la sphère. Les deux portions de sphère c'est à dire celle de la cathode 1 et celle de la grille 3 ont leur centre sur l'axe XX'. La figure 1 b montre de face le dessin de la grille. Lorsque la cathode 1 chauffe du matériau émissif s'évapore et il va recouvrir notamment la grille 3. En chauffant la grille se met à émettre des électrons parasites. Le refroidissement de la grille 3 s'effectue d'une part par conduction vers le support périphérique 6 par l'intermédiaire des premiers et des seconds barreaux 7, 8, et d'autre part par rayonnement vers l'anode 4 essentiellement.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. When the cathode 1 heats the emissive material evaporates and it will cover in particular the grid 3. By heating the grid begins to emit parasitic electrons. 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.
La partie la plus chaude de la grille 3 est sa partie centrale. Toute augmentation de la taille de la cathode 1 conduit à augmenter la taille de la grille 3 et donc la température de sa partie centrale. Pour éviter d'augmenter rémission parasite de la grille 3, on est contraint de limiter la taille de la cathode 1 et par conséquent le courant électronique qu'elle fournit.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.
Les figures 2a et 2b montrent de face et en coupe longitudinale un exemple d'une cathode 10 d'un canon conforme à l'invention. Sur cette figure, la cathode est une portion de sphère. Elle comporte une partie emissive 12 qui délimite un évidement 11 sensiblement central.Figures 2a and 2b show from the front and in longitudinal section an example of a cathode 10 of a gun according to the invention. In this figure, the cathode is a portion of a sphere. It comprises an emissive part 12 which defines a substantially central recess 11.
De préférence, dans un but de simplification la partie emissive 12 est concave et sensiblement en forme de segment de sphère et l'evidement 11 est sensiblement circulaire. La surface emissive d'une cathode telle que celle de la figure 1a varie au premier ordre comme le carré de son diamètre. Dans le cas d'une cathode selon l'invention avec un évidement, si le diamètre de l'evidement 11 représente environ 30 à 40 % du diamètre de la cathode 10, la surface de l'evidement 11 est relativement petite et n'a pratiquement pas d'influence sur l'émission électronique. La faible perte de surface emissive peut être compensée par une faible augmentation du diamètre de la cathode 10. Par exemple, une cathode classique pleine en forme de calotte sphérique de 38 millimètres de diamètre a la même surface qu'une cathode selon l'invention dont la partie emissive est en segment sphérique de 40 millimètres de diamètre et dont l'evidement a un diamètre de 15 millimètres . La figure 3 représente le dessin d'une grille d'un canon selon l'invention. Cette grille est destinée à être associée à une cathode de type de celle représentée sur les figures 2a et 2b. La grille comporte une partie 24 pleine, rayonnant thermiquement, destinée à être disposée face à l'evidement de la cathode. Lorsque la grille est montée dans un canon à électrons avec une telle cathode émettant des électrons, elle peut rayonner d'une part vers l'anode et d'autre part vers l'evidement de la cathode. Cette grille est refroidie efficacement et l'émission d'électrons parasite est éliminée. Avec un meilleur refroidissement de la grille, le diamètre de la cathode est dissocié de la température de la grille et on peut envisager de concevoir des tubes électroniques plus puissants avec ce type de canon.Preferably, for the sake of simplification, 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. In the case of a cathode according to the invention with a recess, if 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. For example, a conventional solid cathode in the shape of a spherical cap 38 millimeters in diameter has the same surface as a cathode according to the invention, the emissive part is in a spherical segment 40 millimeters in diameter and the recess of which has a diameter of 15 millimeters. 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. 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. With better cooling of the grid, 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.
Dans un mode de réalisation préféré de la grille, la partie 24 pleine de la grille 23 est réalisée dans un matériau ayant une capacité de rayonnement thermique proche de celle du corps noir. Le graphite et plus particulièrement le graphite pyrolitique est un matériau particulièrement bien adapté pour réaliser cette partie pleine 24 rayonnant thermiquement.In a preferred embodiment of the grid, 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.
La grille représentée sur la figure 3 comporte autour de la partie 24 pleine une partie ajourée 26 qui est destinée à être traversée par les électrons émis par la cathode. La partie ajourée 26 pourra aussi être réalisée en graphite pyrolitique à cause de ses propriétés thermiques, électriques et mécaniques avantageuses.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.
Si la grille 23 est destinée à être utilisée avec une cathode sensiblement en forme de portion de sphère, il est préférable qu'elle soit aussi sensiblement en forme de portion de sphère. La partie 24 pleine peut être en forme de calotte sphérique et la partie ajourée 26 peut comporter des premiers barreaux 28 disposés selon des méridiens de la sphère et des seconds barreaux 29 selon des parallèles de la sphère.If 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.
La grille 23 peut être réalisée à partir d'une ébauche en graphite pyrolitique, par exemple en forme de portion de sphère, dans laquelle on taille les barreaux 28, 29 et la partie pleine 24. Cette taille peut être réalisée de manière classique, par exemple par usinage laser ou par sablage au jet. On pourrait aussi envisager que la partie ajourée 26 de la grille comporte des ouvertures sensiblement rectangulaires ou hexagonales.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.
La figure 4 montre en coupe longitudinale, un exemple d'un canon à électrons selon l'invention monté dans un tube électronique également conforme à l'invention. Le canon comporte une cathode 21 selon l'invention et une grille de commande 23 toutes les deux sensiblement en forme de portion de sphère. Sur la figure, la cathode 21 comporte une partie emissive 27 en forme de segment de sphère qui délimite un évidement 22 sensiblement central. Une anode 25 et un dispositif de chauffage 40 de la cathode ont aussi été représentés sur cette figure. Le tube électronique est représenté partiellement. Il comporte le canon à électrons et les électrons émis sont récupérés enfin de course dans un collecteur 43.Figure 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. In the figure, 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.
Sur cette, figure, la grille 23 associée à la cathode selon l'invention comporte une partie pleine 24. Elle est comparable à celle de la figure 3. Sa dissipation thermique est meilleure que dans le canon de la figure 1 a.In this, figure, 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.
Si on entoure la grille 23 d'un support périphérique 30 réalisé dans un matériau bon conducteur thermique, tel que du cuivre, la dissipation thermique est encore meilleure. Dans cette configuration, les barreaux 28, 29 de la grille sont refroidis par conduction, à la fois vers le support périphérique 30 et vers la partie pleine 24 rayonnant thermiquement. La partie pleine 24 est refroidie par rayonnement vers l'anode 25 et vers l'evidement 22 de la cathode 21. La longueur des premiers barreaux 28 est considérablement réduite par rapport à celle des barreaux de la figure 1b. Par exemple, leur longueur peut passer d'environ 41 millimètres à environ 14, 5 millimètres dans l'exemple cité précédemment .If the grid 23 is surrounded by a peripheral support 30 made of a material which is a good thermal conductor, such as copper, the heat dissipation is even better. In this configuration, 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.
De préférence, pour une meilleure efficacité du refroidissement et une perturbation minimale du faisceau d'électrons émis, la partie pleine 24 de la grille 23 aura sensiblement la même taille que l'evidement 22 de la cathode 21.Preferably, for better cooling efficiency and minimal disturbance of the electron beam emitted, the solid part 24 of the grid 23 will have substantially the same size as the recess 22 of the cathode 21.
On aurait pu envisager que la cathode selon l'invention soit associée à une grille sans partie pleine, c'est à dire une grille traditionnelle comme celle de la figure 1b, par exemple. Si cette grille est réalisée dans un matériau ayant une capacité de rayonnement proche de celle du corps noir, la partie de la grille face à l'evidement de la cathode peut rayonner vers cet évidement. Le refroidissement de la partie centrale de la grille est amélioré par rapport à celui d'une grille telle que représentée sur la figure 1a et associée à une cathode pleine mais il est moins bon que dans le cas de la figure 4. Toutefois dans certains cas, ce refroidissement est tout à fait suffisant.One could have envisaged that 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.
La cathode doit être chauffée pour pouvoir émettre des électrons. Un dispositif de chauffage 40 indirect de la cathode a été représenté sur la figure 4. Il est vu de face sur la figure 5. Il est prévu pour chauffer la partie emissive 27 de la cathode 21. Il est disposé à proximité de la face convexe de la cathode 21. Il comporte un élément chauffant 42 délimitant un évidement 41 face à l'evidement 22 de la cathode 21. Il peut être en forme de plateau ajouré définissant un réseau de conducteurs 45 dans lequel peut circuler un courant électrique. Ce plateau sera réalisé, de préférence dans un matériau conducteur électrique, ayant une capacité de rayonnement thermique proche de celle du corps noir. Le graphite pyrolitique est particulièrement adapté pour réaliser l'élément chauffant 42. Sur l'exemple de la figure 5, le plateau comporte une série de fentes 44 en arc de cercle concentriques, les fentes 44 placées sur deux cercles successifs étant décalées les unes par rapport aux autres. L'espace entre les fentes 44 forme le réseau de conducteurs 42 électriques.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. In the example of FIG. 5, 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.
Le canon selon l'invention n'est pas limité à une cathode en portion de sphère, ni à une grille en portion de sphère. The barrel according to the invention is not limited to a cathode in portion of sphere, nor to a grid in portion of sphere.

Claims

REVENDICATIONS
1- Canon à électrons à grille comportant une cathode avec une partie emissive (27), caractérisé en ce que la partie emissive (27) délimite un évidement (22) qui la traverse de part en part et qui est sensiblement central de manière à contribuer au refroidissement de la grille.1- Grid electron gun comprising a cathode with an emissive part (27), characterized in that the emissive part (27) delimits a recess (22) which passes right through it and which is substantially central so as to contribute when the grid cools down.
2- Canon à électrons selon la revendication 1 , caractérisé en ce que la partie emissive (27) de la cathode est sensiblement un segment de sphère.2- electron gun according to claim 1, characterized in that the emissive part (27) of the cathode is substantially a segment of sphere.
3- Canon à électrons selon l'une des revendications 1 ou 2, caractérisé en ce que l'evidement (22) de la cathode est sensiblement circulaire.3- electron gun according to one of claims 1 or 2, characterized in that the recess (22) of the cathode is substantially circular.
4- Canon à électrons selon l'une des revendications 2 ou 3, caractérisé en ce que le diamètre de l'evidement (22) de la cathode représente environ 30 à 40% du diamètre de la partie emissive (27).4- electron gun according to one of claims 2 or 3, characterized in that the diameter of the recess (22) of the cathode represents about 30 to 40% of the diameter of the emissive part (27).
5- Canon à électrons selon l'une des revendications 1 à 4, caractérisé en ce qu'il comporte un dispositif de chauffage (40) de la cathode avec un élément chauffant (42) délimitant un évidement (41 ) disposé face à l'evidement (22) de la cathode.5- electron gun according to one of claims 1 to 4, characterized in that it comprises a heating device (40) of the cathode with a heating element (42) delimiting a recess (41) disposed facing the recess (22) of the cathode.
6- Canon à électrons selon la revendication 5, caractérisé en ce que l'élément chauffant (42) est un plateau ajouré définissant un réseau de conducteurs (45) électriques.6. An electron gun according to claim 5, characterized in that the heating element (42) is an openwork plate defining a network of electrical conductors (45).
7- Canon à électrons selon l'une des revendications 5 ou 6, caractérisé en ce que l'élément chauffant (42) est réalisé en graphite pyrolitique.7- electron gun according to one of claims 5 or 6, characterized in that the heating element (42) is made of pyrolitic graphite.
8- Canon à électrons selon l'une des revendications 1 à 7, caractérisé en ce que la grille possède une partie (24) pleine, rayonnant thermiquement, destinée à être disposée face à l'evidement (22) de la cathode (21).8- electron gun according to one of claims 1 to 7, characterized in that the grid has a part (24) full, radiating thermally, intended to be disposed facing the recess (22) of the cathode (21).
9- Canon à électrons selon la revendication 8, caractérisé en ce que la partie (24) pleine de la grille, rayonnant thermiquement, a sensiblement les mêmes dimensions que l'evidement (22) de la cathode (21).9. An electron gun according to claim 8, characterized in that the part (24) full of the grid, radiating thermally, has substantially the same dimensions as the recess (22) of the cathode (21).
10- Canon à électrons selon l'une des revendications 8 ou 9 , caractérisé en ce que la partie (24) pleine de la grille, rayonnant thermiquement, est réalisée dans un matériau ayant une capacité de rayonnement thermique proche de celle du corps noir.10- electron gun according to one of claims 8 or 9, characterized in that the part (24) full of the grid, radiating thermally, is made of a material having a thermal radiation capacity close to that of the black body.
11- Canon à électrons selon la revendication 10, caractérisé en ce que la partie (24) pleine de la grille, rayonnant thermiquement, est réalisée en graphite pyrolitique.11- electron gun according to claim 10, characterized in that the part (24) full of the grid, radiating thermally, is made of pyrolitic graphite.
12- Canon à électrons selon l'une des revendications 8 à 11, caractérisé en ce que la grille comporte une partie ajourée (26) autour de la partie (24) pleine, cette partie ajourée (26) étant destinée à être traversée par les électrons émis par la cathode (21).12- An electron gun according to one of claims 8 to 11, characterized in that the grid has an openwork part (26) around the full part (24), this openwork part (26) being intended to be crossed by the electrons emitted by the cathode (21).
13- Canon à électrons selon la revendication 12, caractérisé en ce que la grille sensiblement en forme de portion de sphère comporte une partie ajourée avec des premiers barreaux (28) disposés selon des méridiens de la sphère et des seconds barreaux (29) selon des parallèles de la sphère.13. An electron gun according to claim 12, characterized in that the grid substantially in the form of a portion of a sphere comprises an openwork part with first bars (28) arranged along meridians of the sphere and second bars (29) according to parallels of the sphere.
14- Canon à électrons selon l'une des revendications 8 à 13, caractérisé en ce que la partie (24) pleine de la grille, rayonnant thermiquement, est sensiblement en calotte sphérique.14. An electron gun according to one of claims 8 to 13, characterized in that the part (24) full of the grid, radiating thermally, is substantially in a spherical cap.
15- Canon à électrons selon l'une des revendications 1 à 14, caractérisé en ce que la grille est entourée d'un support périphérique (30) réalisé dans un matériau bon conducteur thermique. 16- Tube électronique caractérisé en ce qu'il comporte un canon à électrons à grille s.elon l'une des revendications 1 à 15. 15. An electron gun according to one of claims 1 to 14, characterized in that the grid is surrounded by a peripheral support (30) made of a material which is a good thermal conductor. 16- Electronic tube characterized in that it comprises an electron gun with a grid s. According to one of claims 1 to 15.
EP96914252A 1995-05-05 1996-04-26 Grid electron gun Expired - Lifetime EP0824758B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9505408A FR2733856B1 (en) 1995-05-05 1995-05-05 CATHODE FOR GRID ELECTRON CANON, GRID TO BE ASSOCIATED WITH SUCH A CATHODE AND ELECTRON CANON INCLUDING SUCH CATHODE
FR9505408 1995-05-05
PCT/FR1996/000644 WO1996035219A1 (en) 1995-05-05 1996-04-26 Grid electron gun

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EP0824758A1 true EP0824758A1 (en) 1998-02-25
EP0824758B1 EP0824758B1 (en) 2001-08-16

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JP (1) JP4019431B2 (en)
CN (1) CN1099689C (en)
DE (1) DE69614520T2 (en)
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Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9712243D0 (en) * 1997-06-13 1997-08-13 Eev Ltd Grids
FR2775118B1 (en) 1998-02-13 2000-05-05 Thomson Tubes Electroniques GRID FOR ELECTRONIC TUBE WITH AXIAL BEAM WITH IMPROVED PERFORMANCE
FR2789800B1 (en) 1999-02-16 2001-05-11 Thomson Tubes Electroniques VERY HIGH POWER RADIO FREQUENCY GENERATOR
GB9915925D0 (en) * 1999-07-08 1999-09-08 Univ Loughborough Flow field plates
US7345290B2 (en) * 1999-10-07 2008-03-18 Agere Systems Inc Lens array for electron beam lithography tool
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 (en) * 2003-04-04 2006-09-08 Thales Sa CONTROL GRID OF AN ELECTRONIC TUBE
JP4113032B2 (en) * 2003-04-21 2008-07-02 キヤノン株式会社 Electron gun and electron beam exposure apparatus
JP5148582B2 (en) 2009-10-20 2013-02-20 株式会社エー・アンド・デイ Leak tester using pressure
CN105414732B (en) * 2015-12-23 2018-06-29 哈尔滨工业大学（威海） More cathode electronics gun apparatus
CN106216788B (en) * 2016-08-23 2019-07-02 安徽华东光电技术研究所 A kind of welding method that aperture plate welding tooling is controlled electronically
WO2021253197A1 (en) * 2020-06-15 2021-12-23 Shanghai United Imaging Healthcare Co., Ltd. Electron gun

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR960750A (en) * 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 (en) * 1961-12-13 1966-03-10 Deutsche Bundespost Flat cathode for electron beam tubes
FR1523248A (en) * 1967-03-07 1968-05-03 Thomson Houston Comp Francaise Improvements in methods of manufacturing electrodes in the form of grids for electron tubes, electrodes manufactured using these improved methods and electron tubes containing such electrodes
DE2214660A1 (en) * 1971-04-12 1973-12-06 Werk Fernsehelektronik Veb CATODE FOR RUNTIME TUBES
FR2445605A1 (en) * 1978-12-27 1980-07-25 Thomson Csf DIRECT HEATING CATHODE AND HIGH FREQUENCY ELECTRONIC TUBE COMPRISING SUCH A CATHODE
FR2498372A1 (en) * 1981-01-16 1982-07-23 Thomson Csf DIRECT HEATING CATHODE, METHOD FOR MANUFACTURING SAME, AND ELECTRONIC TUBE INCLUDING SUCH A CATHODE
FR2532468A1 (en) * 1982-08-31 1984-03-02 Thomson Csf IMPROVEMENT TO CATHODES WITH DIRECT HEATING
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
FR2693028A1 (en) * 1992-06-26 1993-12-31 Thomson Tubes Electroniques Electron gun with reduced heating of the grid.
FR2728386B1 (en) * 1994-12-20 1997-01-24 Thomson Tubes Electroniques ELECTRONIC TUBE WITH IMPROVED PERFORMANCE GRID

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9635219A1 *

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FR2733856B1 (en) 1997-08-29
US5936335A (en) 1999-08-10
CN1099689C (en) 2003-01-22
CN1183852A (en) 1998-06-03
JPH11505059A (en) 1999-05-11
EP0824758B1 (en) 2001-08-16
WO1996035219A1 (en) 1996-11-07
FR2733856A1 (en) 1996-11-08
DE69614520D1 (en) 2001-09-20
JP4019431B2 (en) 2007-12-12
DE69614520T2 (en) 2002-05-08

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