EP0251830B1 - Multiple beam lasertron - Google Patents

Multiple beam lasertron Download PDF

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Publication number
EP0251830B1
EP0251830B1 EP87401020A EP87401020A EP0251830B1 EP 0251830 B1 EP0251830 B1 EP 0251830B1 EP 87401020 A EP87401020 A EP 87401020A EP 87401020 A EP87401020 A EP 87401020A EP 0251830 B1 EP0251830 B1 EP 0251830B1
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EP
European Patent Office
Prior art keywords
tube
photocathodes
lasertron
laser beam
optical system
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EP87401020A
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German (de)
French (fr)
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EP0251830A1 (en
Inventor
Duc Tien Tran
Georges Faillon
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Thales SA
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Thomson CSF SA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/02—Electrodes; Magnetic control means; Screens
    • H01J23/04—Cathodes
    • 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
    • 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
    • H01J3/021—Electron guns using a field emission, photo emission, or secondary emission electron source
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/34—Photoemissive electrodes
    • H01J2201/342—Cathodes

Definitions

  • the present invention relates to multiple beam lasertrons.
  • a photocathode is illuminated by a laser beam, the wavelength of which is chosen as a function of the output work of the material from which the photocathode is made.
  • a pulsed laser beam at frequency F tears out of the photocathode, at this same frequency F, packets of electrons. These electron packets are then accelerated in an electrostatic electric field and thus gain kinetic energy. They then cross a cavity resonating at frequency F and their kinetic energy is transformed into electromagnetic energy at frequency F. We take the energy from the cavity by coupling it to an external use circuit.
  • FIGS. 1 and 2 two embodiments of lasertrons according to the prior art have been represented schematically and seen in longitudinal section.
  • An arrangement of the type shown in FIG. 2 is known, for example, from American patent US-A 3,403,257.
  • references 1, 2 and 3 respectively designate the photocathode, the laser beam and the electron beam.
  • the photocathode 1 is illuminated obliquely by the laser fascia 2 and the electron beam 3 propagates along the longitudinal axis XX 'of the tube.
  • the laser beam 2 and the electron beam 3 propagate along the longitudinal axis XX 'of the tube, but in the opposite direction.
  • the laser beam 2 is therefore normal to the emissive surface of the photocathode.
  • the electron beam 3 is accelerated by the electrostatic electric field created by an anode 4, then enters a cavity 5 resonating at the frequency F.
  • a collector 6 then receives the electron beam.
  • the electromagnetic energy is taken at the frequency F from the cavity 5 by coupling it to an external use circuit, by a waveguide 7, associated with a window 8, as in FIG. 1 or by a loop 9, as in figure 2.
  • lasertrons are very compact tubes. In lasertrons, electron packets are torn off at the photocathode at frequency F. Whereas in tubes such as klystrons, it is necessary to use several cavities to distribute the electrons of an initially continuous beam into packets.
  • the present invention provides a new structure of lasertrons which makes it possible to avoid the drawbacks of known lasertrons.
  • the present invention relates to a lasertron according to claim 1.
  • the invention provides a new structure of lasertrons, called multiple beam lasertrons. Two embodiments of these lasertrons are shown seen in longitudinal section in FIGS. 3 and 4.
  • Multi-beam klystrons are known from the prior art by articles, as well as by French patent n ° 992.853. These klystrons have also been described in French patent applications FR-A 2 596 199 (see also EP-A 0 239 466) and FR-A 2 596 198, filed on March 19, 1986, in the name of the Applicant. A great advantage of these klystrons is that they are particularly suitable for operation at very high power. Indeed, it is shown that for the same high frequency power, the acceleration voltage applied between the anode and a cathode of the klystron is much lower in a klystron with multiple beams than in klystrons with a single beam.
  • Multi-beam klystrons generally operate in the TMoi mode.
  • Multiple beam lasertrons are obtained by making modifications to the same beam lasertrons of the same type as those made to single beam klystrons to obtain multiple beam klystrons.
  • n photocathodes lit by a laser beam are used.
  • Each photocathode produces an electron beam which crosses at least one resonance cavity with n sliding tubes, before arriving at a collector.
  • Multibeam lasertrons therefore make it possible to obtain high powers of high frequency and when they operate in TMo 2 mode, large powers and high frequencies.
  • FIG. 3 shows by way of example the modifications made to the lasertron of FIG. 1 in order to obtain a lasertron with multiple beams.
  • n photocathodes marked with the reference 1, are used; they are illuminated by the laser beam 2.
  • n photocathodes 1 produce n electron beams 3 which are accelerated by n anodes 4 positively polarized with respect to the cathodes.
  • n beams 3 pass through a cavity 5 to n sliding tubes 16 and give up their kinetic energy therein in the form of electromagnetic energy before being collected in the collector 6.
  • the multiple beam lasertron of FIG. 3 always has the drawbacks indicated in the introduction to the description with regard to the single beam lasertron of FIG. 1.
  • FIG. 4 is a cross-sectional view of a lasertron with multiple beams of entirely new structure and which does not have the drawbacks of the lasertrons of FIGS. 1, 2, and 3.
  • This lasertron has n photocathodes 1 which are regularly distributed around the longitudinal axis XX 'of the tube.
  • An incident laser beam 2 arrives on an optical system 10, which can be constituted by a lens, made of quartz, for example.
  • the incident laser beam is annular.
  • This optical system 10 is centered on the axis XX '. It is placed before the collector, according to the direction of propagation of the laser beam, as it appears in FIG. 4.
  • the optical system produces a laser beam which moves parallel to the longitudinal axis XX 'of the tube.
  • the lasertron of FIG. 4 comprises a single resonance cavity 5, the walls 12 and 13 of which, perpendicular to the axis XX ', are pierced with n orifices 14. These orifices make it possible to obtain in operation n laser beams.
  • a cooling device is arranged on the wall 12 of the cavity 5 which receives the impact of the laser beam and which transforms it into n laser beams. Part of the laser power is thus collected.
  • the diameter of the orifices 14 allowing the passage of the n laser beams is chosen, as well as the thickness of the walls 12 and 13 of the cavity, so as to limit the leakage of the electromagnetic energy coming from the cavity.
  • another optical system 11 is arranged, which may be constituted by a lens; this optical system 11 ensures the deflection of the n laser beams so that they illuminate the n photocathodes at an angle as little inclined as possible.
  • the optical system 11 comprises a plate 15 ensuring its protection against various deposits, which can result from the evaporation of various constituents of the photocathodes.
  • n photocathodes being lit by n laser beams, each emit an electron beam 3, focused by anodes 4, and which pass through the cavity 5 by n sliding tubes 16 before falling on the collector 6.
  • the electromagnetic power is taken by a waveguide 7, through a dielectric window 8.
  • Coils 9 ensure the focusing of the n electron beams.
  • the lasertron of Figure 4 in addition to the inherent advantages of multiple beam lasertrons, has many advantages.
  • the optical system which produces the laser beam and which focuses it does not receive an electron beam which risks damaging it and making it opaque.
  • the two optical systems 10 and 11 are also protected from electron beams.
  • the plate 15 protects the lens 11 from products which may come from the photocathodes.
  • the laser beams illuminate the photocathodes with an almost normal incidence which improves the light output of the photocathodes.
  • lasertrons comprising several successive cavities, generally two, are known.
  • the invention therefore relates to laserers with multiple beams, having one or more successive cavities.

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Description

La présente invention concerne les lasertrons à faisceaux multiples.The present invention relates to multiple beam lasertrons.

Il est connu, par des articles et par le brevet américain 4.313.072 (voir aussi DE-A 3 038 405), des tubes électroniques appelés "lasertrons".It is known, from articles and from American patent 4,313,072 (see also DE-A 3,038,405), electronic tubes called "lasertrons".

Dans ces tubes, une photocathode est éclairée par un faisceau laser dont la longueur d'onde est choisie en fonction du travail de sortie du matériau dont est réalisée la photocathode. Ainsi un faisceau laser pulsé à la fréquence F arrache à la photocathode, à cette même fréquence F, des paquets d'électrons. Ces paquets d'électrons sont ensuite accélérés dans un champ électrique électrostatique et ainsi gagnent en énergie cinétique. Ils traversent ensuite une cavité résonnant à la fréquence F et leur énergie cinétique se transforme en énergie électromagnétique à la fréquence F.On prélève l'énergie de la cavité en la couplant à un circuit d'utilisation externe.In these tubes, a photocathode is illuminated by a laser beam, the wavelength of which is chosen as a function of the output work of the material from which the photocathode is made. Thus a pulsed laser beam at frequency F tears out of the photocathode, at this same frequency F, packets of electrons. These electron packets are then accelerated in an electrostatic electric field and thus gain kinetic energy. They then cross a cavity resonating at frequency F and their kinetic energy is transformed into electromagnetic energy at frequency F. We take the energy from the cavity by coupling it to an external use circuit.

Sur les figures 1 et 2, deux modes de réalisation de lasertrons selon l'art antérieur ont été représentés de façon schématique et vus en coupe longitudinale. Une disposition du type représenté sur la figure 2 est connue, par exemple, du brevet américain US-A 3 403 257.In FIGS. 1 and 2, two embodiments of lasertrons according to the prior art have been represented schematically and seen in longitudinal section. An arrangement of the type shown in FIG. 2 is known, for example, from American patent US-A 3,403,257.

Sur ces figures, les références 1, 2 et 3 désignent respectivement la photocathode, le faisceau laser et le faisceau d'électrons.In these figures, the references 1, 2 and 3 respectively designate the photocathode, the laser beam and the electron beam.

Dans le mode de réalisation de la figure 1, la photocathode 1 est éclairée obliquement par le fasceau laser 2 et le faisceau d'électrons 3 se propage selon l'axe longitudinal XX' du tube.In the embodiment of Figure 1, the photocathode 1 is illuminated obliquely by the laser fascia 2 and the electron beam 3 propagates along the longitudinal axis XX 'of the tube.

Dans le mode de réalisation de la figure 2, le faisceau laser 2 et le faisceau d'électrons 3 se propagent selon l'axe longitudinal XX' du tube, mais en sens inverse.In the embodiment of FIG. 2, the laser beam 2 and the electron beam 3 propagate along the longitudinal axis XX 'of the tube, but in the opposite direction.

Le faisceau laser 2 est donc normal à la surface émissive de la photocathode.The laser beam 2 is therefore normal to the emissive surface of the photocathode.

Le faisceau d'électrons 3 est accéléré par le champ électrique électrostatique créé par une anode 4, puis pénètre dans une cavité 5 résonnant à la fréquence F. Un collecteur 6 reçoit ensuite le faisceau d'électrons. On prélève l'énergie électromagnétique à la fréquence F sur la cavité 5 en la couplant à un circuit d'utilisation externe, par un guide d'onde 7, associé à une fenêtre 8, comme sur la figure 1 ou par une boucle 9, comme sur la figure 2.The electron beam 3 is accelerated by the electrostatic electric field created by an anode 4, then enters a cavity 5 resonating at the frequency F. A collector 6 then receives the electron beam. The electromagnetic energy is taken at the frequency F from the cavity 5 by coupling it to an external use circuit, by a waveguide 7, associated with a window 8, as in FIG. 1 or by a loop 9, as in figure 2.

L'intérêt des lasertrons est qu'il s'agit de tubes très compacts. Dans les lasertrons, on arrache à la photocathode des paquets d'électrons à la fréquence F. Alors que dans des tubes tels que les klystrons, il faut utiliser plusieurs cavités pour répartir les électrons d'un faisceau initialement continu en paquets.The advantage of lasertrons is that they are very compact tubes. In lasertrons, electron packets are torn off at the photocathode at frequency F. Whereas in tubes such as klystrons, it is necessary to use several cavities to distribute the electrons of an initially continuous beam into packets.

Le problème qui se pose avec les lasertrons est qu'il sont limités en fréquence, et en puissance.The problem with lasertrons is that they are limited in frequency, and in power.

Ainsi par exemple, pour produire de grandes puissances, il faut extraire un courant important, ce qui nécessite une cathode de grande surface et entraîne le passage d'un faisceau important dans la cavité. Il faut alors que les dimensions de la cavité soient suffisantes pour permettre le passage de ce faisceau, ce qui limite la fréquence de fonctionnement. De plus, l'utilisation d'une cavité de grandes dimensions produit un mauvais couplage entre le faisceau et la cavité, ce qui entraîne un mauvais rendement.Thus for example, to produce large powers, it is necessary to extract a large current, which requires a cathode of large area and causes the passage of a large beam in the cavity. It is then necessary that the dimensions of the cavity are sufficient to allow the passage of this beam, which limits the operating frequency. In addition, the use of a large cavity produces poor coupling between the beam and the cavity, which results in poor efficiency.

Les modes de réalisation de lasertrons qui sont représentés sur les figures 1 et 2 présentent les inconvénients suivants :

  • - dans le mode de réalisation de la figure 1, la photocathode est éclairée obliquement. Il en résulte d'une part, un mauvais rendement lumineux de la photocathode et d'autre part, un dispositif d'éclairage par faisceau laser qu'il faut rendre aussi peu encombrant que possible pour le loger à proximité de pièces à haute tension ;
  • - dans le mode de réalisation de la figure 2, le faisceau laser et le faisceau d'électrons empruntent le même chemin. En conséquence, la surface de la photocathode qui reçoit le faisceau laser est limitée par le diamètre D du tube de glissement de la cavité 5 qui permet le passage de ces faisceaux. Par ailleurs, le dispositif d'éclairage par faisceau laser est soumis au bombardement du faisceau d'électrons.
The embodiments of lasertrons which are represented in FIGS. 1 and 2 have the following drawbacks:
  • - In the embodiment of Figure 1, the photocathode is lit obliquely. This results on the one hand, a poor light output of the photocathode and on the other hand, a laser beam lighting device which must be made as compact as possible to accommodate it near high voltage parts;
  • - In the embodiment of Figure 2, the laser beam and the electron beam take the same path. Consequently, the surface of the photocathode which receives the laser beam is limited by the diameter D of the sliding tube of the cavity 5 which allows the passage of these beams. Furthermore, the laser beam lighting device is subjected to bombardment of the electron beam.

La présente invention propose une nouvelle structure de lasertrons qui permet d'éviter les inconvénients des lasertrons connus.The present invention provides a new structure of lasertrons which makes it possible to avoid the drawbacks of known lasertrons.

La présente invention concerne un lasertron selon la revendication 1.The present invention relates to a lasertron according to claim 1.

D'autres objets, caractéristiques et résultats de l'invention ressortiront de la description suivante, donnée à titre d'exemple non limitatif et illustrée par les figures annexées qui représentent ;

  • - les figures 1 et 2, des vues en coupe longitudinale de deux modes de réalisation de lasertrons selon l'art antérieur ;
  • - les figures 3 et 4, des vues en coupe longitudinale de deux modes de réalisation de lasertrons selon l'invention.
Other objects, characteristics and results of the invention will emerge from the following description, given by way of nonlimiting example and illustrated by the appended figures which represent;
  • - Figures 1 and 2, views in longitudinal section of two embodiments of lasertrons according to the prior art;
  • - Figures 3 and 4, views in longitudinal section of two embodiments of lasertrons according to the invention.

Sur les différentes figures, les mêmes repères désignent les mêmes éléments, mais, pour des raisons de clarté, les cotes et proportions des divers éléments ne sont pas respectées.In the various figures, the same references designate the same elements, but, for reasons of clarity, the dimensions and proportions of the various elements are not observed.

Les figures 1 et 2 ont été décrites dans l'introduction à la description.Figures 1 and 2 have been described in the introduction to the description.

L'invention propose une nouvelle structure de lasertrons, appelés lasertrons à faisceaux multiples. Deux modes de réalisation de ces lasertrons sont représentés vus en coupe longitudinale sur les figures 3 et 4.The invention provides a new structure of lasertrons, called multiple beam lasertrons. Two embodiments of these lasertrons are shown seen in longitudinal section in FIGS. 3 and 4.

Les klystrons à faisceaux multiples sont connus de l'art antérieur par des articles, ainsi que par le brevet français n° 992.853. Ces klystrons ont été également décrits dans les demandes de brevets français FR-A 2 596 199 (voir aussi EP-A 0 239 466) et FR-A 2 596 198, déposées le 19 mars 1986, au nom de la Demanderesse. Un grand avantage de ces klystrons est qu'ils sont particulièrement adaptés à un fonctionnement à très grande puissance. En effet, on démontre que pour une même puissance de haute fréquence, la tension d'accélération appliquée entre l'anode et une cathode du klystron est beaucoup plus faible dans un klystron à faisceaux multiples que dans les klystrons à un seul faisceau. Or quel que soit le type de klystron, la nécessité de moduler la vitesse du faisceau d'électrons impose à cette tension d'accélération une même limite supérieure à partir de laquelle le fasceau n'est plus modulable. En conséquence, on peut obtenir avec un klystron à faisceaux multiples une puissance de haute fréquence beaucoup plus élevée que celle qu'il est possible d'obtenir avec un klystron à un seul faisceau.Multi-beam klystrons are known from the prior art by articles, as well as by French patent n ° 992.853. These klystrons have also been described in French patent applications FR-A 2 596 199 (see also EP-A 0 239 466) and FR-A 2 596 198, filed on March 19, 1986, in the name of the Applicant. A great advantage of these klystrons is that they are particularly suitable for operation at very high power. Indeed, it is shown that for the same high frequency power, the acceleration voltage applied between the anode and a cathode of the klystron is much lower in a klystron with multiple beams than in klystrons with a single beam. However whatever the type of klystron, the need to modulate the speed of the electron beam imposes on this acceleration voltage the same upper limit from which the fascia is no longer modular. As a result, you can get a much higher high frequency power with a multiple beam klystron than you can get with a single beam klystron.

Les klystrons à faisceaux multiples fonctionnent généralement sur le mode TMoi.Multi-beam klystrons generally operate in the TMoi mode.

Il est possible d'obtenir des klystrons à faisceaux multiples de grandes puissances, à des fréquences élevées, en dimensionnant les cavités de façon que ces klystrons fonctionnent de façon optimale au mode TMo2.It is possible to obtain multi-beam klystrons of large powers, at high frequencies, by dimensioning the cavities so that these klystrons function optimally in the TMo 2 mode.

Les lasertrons à faisceaux multiples sont obtenus en apportant aux lasertrons à un seul faisceau des modifications du même type que celles qui sont apportées aux klystrons à un seul faisceau pour obtenir des klystrons à faisceaux multiples.Multiple beam lasertrons are obtained by making modifications to the same beam lasertrons of the same type as those made to single beam klystrons to obtain multiple beam klystrons.

Ainsi, pour obtenir un lasertron à n faisceaux, on utilise n photocathodes éclairées par un faisceau laser. Chaque photocathode produit un faisceau d'électrons qui traverse au moins une cavité de résonance avec n tubes de glissement, avant d'aboutir sur un collecteur.Thus, to obtain a lasertron with n beams, n photocathodes lit by a laser beam are used. Each photocathode produces an electron beam which crosses at least one resonance cavity with n sliding tubes, before arriving at a collector.

Les avantages obtenus du fait du passage aux lasertrons à faisceaux multiples sont semblables à ceux obtenus par le passage des klystrons à un seul faisceau aux klystrons à faisceaux multiples.The advantages obtained from switching to multiple beam lasertrons are similar to those obtained from switching from single beam klystrons to multiple beam klystrons.

Les lasertrons à faisceaux multiples permettent donc d'obtenir des puissances de haute fréquence élevées et lorsqu'ils fonctionnent au mode TMo2, des grandes puissances et des fréquences élevées.Multibeam lasertrons therefore make it possible to obtain high powers of high frequency and when they operate in TMo 2 mode, large powers and high frequencies.

La figure 3 montre à titre d'exemple les modifications apportées au lasertron de la figure 1 pour obtenir un lasertron à faisceaux multiples.FIG. 3 shows by way of example the modifications made to the lasertron of FIG. 1 in order to obtain a lasertron with multiple beams.

Dans le cas d'un lasertron à n faisceaux (n : nombre entier supérieur à 1), n photocathodes, portant la référence 1, sont utilisées ; elles sont éclairées par le faisceau laser 2.In the case of a lasertron with n beams (n: whole number greater than 1), n photocathodes, marked with the reference 1, are used; they are illuminated by the laser beam 2.

Ces n photocathodes 1 produisent n faisceaux d'électrons 3 qui sont accélérés par n anodes 4 polarisées positivement par rapport aux cathodes.These n photocathodes 1 produce n electron beams 3 which are accelerated by n anodes 4 positively polarized with respect to the cathodes.

Les n faisceaux 3 traversent une cavité 5 à n tubes de glissement 16 et y cèdent leur énergie cinétique sous forme d'énergie électromagnétique avant d'être recueillis dans le collecteur 6.The n beams 3 pass through a cavity 5 to n sliding tubes 16 and give up their kinetic energy therein in the form of electromagnetic energy before being collected in the collector 6.

Le lasertron à faisceaux multiples de la figure 3 présente toujours les inconvénients signalés dans l'introduction à la description à propos du lasertron à un seul faisceau de la figure 1.The multiple beam lasertron of FIG. 3 always has the drawbacks indicated in the introduction to the description with regard to the single beam lasertron of FIG. 1.

La figure 4, est une vue en coupe transversale d'un lasertron à faisceaux multiples de structure entièrement nouvelle et qui ne présente pas les inconvénients des lasertrons des figures 1, 2, et 3.FIG. 4 is a cross-sectional view of a lasertron with multiple beams of entirely new structure and which does not have the drawbacks of the lasertrons of FIGS. 1, 2, and 3.

Ce lasertron comporte n photocathodes 1 qui sont régulièrement réparties autour de l'axe longitudinal XX' du tube.This lasertron has n photocathodes 1 which are regularly distributed around the longitudinal axis XX 'of the tube.

Un faisceau laser incident 2 arrive sur un système optique 10, qui peut être constitué par une lentille, en quartz, par exemple.An incident laser beam 2 arrives on an optical system 10, which can be constituted by a lens, made of quartz, for example.

De préférence le faisceau laser incident est annulaire. Ce système optique 10 est centré sur l'axe XX'. Il est placé avant le collecteur, selon le sens de propagation du faisceau laser, comme il apparaît sur la figure 4. Le système optique produit un faisceau laser qui se déplace parallèlement à l'axe longitudinal XX' du tube.Preferably the incident laser beam is annular. This optical system 10 is centered on the axis XX '. It is placed before the collector, according to the direction of propagation of the laser beam, as it appears in FIG. 4. The optical system produces a laser beam which moves parallel to the longitudinal axis XX 'of the tube.

Le lasertron de la figure 4 comporte une seule cavité de résonance 5, dont les parois 12 et 13, perpendiculaires à l'axe XX', sont percées de n orifices 14. Ces orifices permettent d'obtenir en fonctionnement n faisceaux laser. Un dispositif de refroidissement, non représenté, est disposé sur la paroi 12 de la cavité 5 qui reçoit l'impact du faisceau laser et qui le transforme en n faisceaux lasers. Ainsi une partie de la puissance du laser est recueillie.The lasertron of FIG. 4 comprises a single resonance cavity 5, the walls 12 and 13 of which, perpendicular to the axis XX ', are pierced with n orifices 14. These orifices make it possible to obtain in operation n laser beams. A cooling device, not shown, is arranged on the wall 12 of the cavity 5 which receives the impact of the laser beam and which transforms it into n laser beams. Part of the laser power is thus collected.

Le diamètre des orifices 14 permettant le passage des n faisceaux lasers est choisi, ainsi que l'épaisseur des parois 12 et 13 de la cavité, de manière à limiter la fuite de l'énergie électromagnétique provenant de la cavité.The diameter of the orifices 14 allowing the passage of the n laser beams is chosen, as well as the thickness of the walls 12 and 13 of the cavity, so as to limit the leakage of the electromagnetic energy coming from the cavity.

Après que les n faisceaux lasers aient traversé la cavité, on dispose un autre système optique 11, qui peut être constitué par une lentille ; ce système optique 11 assure la déviation des n faisceaux lasers afin qu'il éclairent les n photocathodes sous un angle aussi peu incliné que possible.After the n laser beams have passed through the cavity, another optical system 11 is arranged, which may be constituted by a lens; this optical system 11 ensures the deflection of the n laser beams so that they illuminate the n photocathodes at an angle as little inclined as possible.

Du côté où il se trouve en vis-à-vis avec les photocathodes, le système optique 11 comporte une plaque 15 assurant sa protection contre des dépôts divers, qui peuvent résulter de l'évaporation de divers constituants des photocathodes.On the side where it is located opposite the photocathodes, the optical system 11 comprises a plate 15 ensuring its protection against various deposits, which can result from the evaporation of various constituents of the photocathodes.

Les n photocathodes, étant éclairées par n faisceaux lasers, émettent chacune un faisceau d'électrons 3, focalisé par des anodes 4, et qui traversent la cavité 5 par n tubes de glissement 16 avant de tomber sur le collecteur 6. Dans la cavité 5, la puissance électromagnétique est prélevée par un guide d'onde 7, à travers une fenêtre diélectrique 8. Des bobines 9 assurent la focalisation des n faisceaux d'électrons.The n photocathodes, being lit by n laser beams, each emit an electron beam 3, focused by anodes 4, and which pass through the cavity 5 by n sliding tubes 16 before falling on the collector 6. In the cavity 5 , the electromagnetic power is taken by a waveguide 7, through a dielectric window 8. Coils 9 ensure the focusing of the n electron beams.

Le lasertron de la figure 4, en plus des avantages inhérents aux lasertrons à faisceaux multiples, présente de nombreux avantages.The lasertron of Figure 4, in addition to the inherent advantages of multiple beam lasertrons, has many advantages.

Ainsi, contrairement à ce qui se produit dans le mode de réalisation de la figure 2, le système optique qui produit le faisceau laser et qui le focalise ne reçoit pas de faisceau d'électrons qui risque de l'endommager et de le rendre opaque.Thus, contrary to what occurs in the embodiment of FIG. 2, the optical system which produces the laser beam and which focuses it does not receive an electron beam which risks damaging it and making it opaque.

Les deux systèmes optiques 10 et 11 sont également protégés des faisceaux d'électrons. La plaque 15 permet de protéger la lentille 11 des produits pouvant venir des photocathodes.The two optical systems 10 and 11 are also protected from electron beams. The plate 15 protects the lens 11 from products which may come from the photocathodes.

Les faisceaux lasers éclairent les photocathodes avec une incidence presque normale ce qui améliore le rendement lumineux des photocathodes.The laser beams illuminate the photocathodes with an almost normal incidence which improves the light output of the photocathodes.

Il est à noter que des lasertrons comportant plusieurs cavités successives, généralement deux, sont connus. L'invention concerne donc les lasertrons à faisceaux multiples, ayant une ou plusieurs cavités successives.It should be noted that lasertrons comprising several successive cavities, generally two, are known. The invention therefore relates to laserers with multiple beams, having one or more successive cavities.

Claims (5)

1. An electron tube of the "lasertron" type, comprising photocathode means adapted to emit electrons when irradiated by a laser beam pulsed at a frequency F, at least one resonant cavity, which resonates at the frequency F, a drift tube permitting the passage of the said electrons, and means for taking electromagnetic energy at the frequency F at the resonant cavity, the said tube comprising: n (n being a whole number greater than unity) photocathodes (1) spaced around a longitudinal axis of the tube, emitting n respective electron beams (3); m (m being a whole number greater than zero) resonant cavities (5) disposed along the said axis, which res- onante at the frequency F; n respective drift tubes (16) permitting the passage of n respective beams (3); a collector (6) centered in the said axis in order to receive the electrons which have passed through the n drift tubes; and director means (11 and 15) for the laser beam, ensuring, in the operative state, an inclined illumination of the photocathodes.
2. The lasertron electron tube as claimed in ctaim 1, characterized in that it comprises a first (10) and a second (1) optical system, centered on the longitudinal axis (XX') of the tube, the first optical system (10), placed in front of the collector (6) in the direction propagation of the laser beam, receiving during operation the laser beam (2) and producing a principal laser beam (2), parallel to the longitudinal axis (XX') of the lasertron, in that those walls (12 and 13) of the cavities (5) which are perpendicular to the longitudinal axis (XX') of the lasertron have n orifices (14) therein which during operation make possible the passage of n secondary laser beams (2), parallel to the axis (XX'), obtained from the principal laser beam, and in that the second optical system (11), which is placed in front of the photocathodes (1) in the direction of the propagation of the laser beams (2), makes possible, during operation, the deflection of n laser beams so that they respectively illuminate the photocathodes (1).
3. The lasertron electron tube as claimed in claim 2, characterized in that it comprises, between the second optical system (11) and the photocathodes (1), a plate which protects the second optical system against the formation of deposits due to evaporation of the materials which are the materials which are the constituents of the photocathodes (1).
4. The electron tube as claimed in any one of the preceding claims 1 through 3, characterized in that the dimensions of the m cavities (5) are such that the tube functions in an optimum manner in the TMo1 mode.
5. The electron tube as claimed in any one of the preceding claims 1 through 3, characterized in that the dimensions of the m cavities (5) are such that the tube functions in an optimum manner in the TMo2 mode.
EP87401020A 1986-05-30 1987-05-04 Multiple beam lasertron Expired - Lifetime EP0251830B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8607826 1986-05-30
FR8607826A FR2599565B1 (en) 1986-05-30 1986-05-30 MULTIPLE BEAM LASERTRON.

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EP0251830A1 EP0251830A1 (en) 1988-01-07
EP0251830B1 true EP0251830B1 (en) 1990-07-11

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EP87401020A Expired - Lifetime EP0251830B1 (en) 1986-05-30 1987-05-04 Multiple beam lasertron

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EP (1) EP0251830B1 (en)
DE (1) DE3763628D1 (en)
FR (1) FR2599565B1 (en)

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Publication number Priority date Publication date Assignee Title
FR2625836B1 (en) * 1988-01-13 1996-01-26 Thomson Csf ELECTRON COLLECTOR FOR ELECTRONIC TUBE
FR2643507A1 (en) * 1989-02-21 1990-08-24 Thomson Tubes Electroniques ELECTRON BEAM WITH ELECTRON BEAM MODULATED BY AN OPTICAL DEVICE
FR2669145B1 (en) * 1990-11-09 1994-02-11 Thomson Tubes Electroniques ELECTRON CANON MODULATED BY OPTOELECTRONIC SWITCHING.
FR2737340B1 (en) * 1995-07-28 1997-08-22 Thomson Tubes Electroniques MULTI-BEAM ELECTRONIC TUBE WITH IMPROVED CAVITY / BEAM COUPLING
FR2756970B1 (en) * 1996-12-10 2003-03-07 Thomson Tubes Electroniques LONGITUDINAL INTERACTION MICROWAVE TUBE WITH OUTPUT BEYOND THE COLLECTOR
FR2764730B1 (en) * 1997-06-13 1999-09-17 Thomson Tubes Electroniques ELECTRONIC CANON FOR MULTI-BEAM ELECTRONIC TUBE AND MULTI-BEAM ELECTRONIC TUBE EQUIPPED WITH THIS CANON
JP3268237B2 (en) * 1997-07-29 2002-03-25 住友重機械工業株式会社 Electron gun using photocathode
FR2780809B1 (en) 1998-07-03 2003-11-07 Thomson Tubes Electroniques MULTI-BEAM ELECTRONIC TUBE WITH MAGNETIC FIELD OF CORRECTION OF BEAM TRAJECTORY
FR2803454B1 (en) * 1999-12-30 2003-05-16 Thomson Tubes Electroniques MICROWAVE PULSE GENERATOR WITH INTEGRATED PULSE COMPRESSOR
US6828574B1 (en) * 2000-08-08 2004-12-07 Applied Materials, Inc. Modulator driven photocathode electron beam generator
US7116051B2 (en) * 2003-07-16 2006-10-03 Vancil Bernard K Multibeam klystron

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3107313A (en) * 1959-10-30 1963-10-15 Johann R Hechtel Velocity modulated electron tube with cathode means providing plural electron streams
US3403257A (en) * 1963-04-02 1968-09-24 Mc Donnell Douglas Corp Light beam demodulator
US3356851A (en) * 1963-10-22 1967-12-05 Picker X Ray Corp Division Inc Image intensifier tube with separable optical coupler
US4313072A (en) * 1979-10-10 1982-01-26 The United States Of America As Represented By The United States Department Of Energy Light modulated switches and radio frequency emitters

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FR2599565B1 (en) 1989-01-13
DE3763628D1 (en) 1990-08-16
FR2599565A1 (en) 1987-12-04
EP0251830A1 (en) 1988-01-07
US4749906A (en) 1988-06-07

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