EP0026949A1 - Secondary-emission electrode, particularly for a photomultiplier - Google Patents

Secondary-emission electrode, particularly for a photomultiplier Download PDF

Info

Publication number
EP0026949A1
EP0026949A1 EP80200903A EP80200903A EP0026949A1 EP 0026949 A1 EP0026949 A1 EP 0026949A1 EP 80200903 A EP80200903 A EP 80200903A EP 80200903 A EP80200903 A EP 80200903A EP 0026949 A1 EP0026949 A1 EP 0026949A1
Authority
EP
European Patent Office
Prior art keywords
layer
secondary emission
antimony
rhodium
electrode
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.)
Withdrawn
Application number
EP80200903A
Other languages
German (de)
French (fr)
Inventor
Jean-Claude Tranchart
Marcel Audier
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.)
Laboratoires dElectronique Philips SAS
Koninklijke Philips NV
Original Assignee
Electronique & Physique
Laboratoires dElectronique et de Physique Appliquee
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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 Electronique & Physique, Laboratoires dElectronique et de Physique Appliquee, Philips Gloeilampenfabrieken NV, Koninklijke Philips Electronics NV filed Critical Electronique & Physique
Publication of EP0026949A1 publication Critical patent/EP0026949A1/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00Details 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
    • H01J1/02Main electrodes
    • H01J1/32Secondary-electron-emitting electrodes

Definitions

  • the invention relates to a secondary emission electrode, very generally comprising at least one metallic support and a layer with a high secondary emission coefficient of an alkaline antimony compound.
  • a secondary emission electrode very generally comprising at least one metallic support and a layer with a high secondary emission coefficient of an alkaline antimony compound.
  • Such an electrode is known from the prior art, and we will cite for example the French patent 1,128,707 in the name of the Applicant.
  • the invention finds its application in the manufacture of photomultiplier tubes, for various uses, in particular for scintillation measurements (research or nuclear medicine, etc.), or for spectrophotometry (image analysis, etc.).
  • a photomultiplier is a tube which groups in a single bulb, a photoelectric cell and a current amplifier, using the secondary emission of electrodes (dynodes) brought to increasing electrical potentials.
  • the gain of the amplifier is directly related to the number of dynodes and their secondary emission coefficient.
  • the dynodes were made inter alia from copper and beryllium alloy (2 "o) and had a secondary emission coefficient of the order of 4, for electrons accelerated at 100 volts.
  • the metal substrate usually used is, for historical reasons, copper-beryllium, and the layer with a high secondary emission coefficient is an alkaline antimony compound, a reaction takes place between the copper and antimony which strongly degrades the emissive properties of said layer, as a result of the formation of an alloy between copper and antimony.
  • the invention aims to overcome this drawback.
  • electrodes with secondary emission very generally comprising a metallic support, an intermediate layer and a layer with high secondary emission factor.
  • the emissive layer is made of an alkali metal carbonate, and on the other hand the intermediate layer plays an important role in increasing the secondary emission of the upper layer.
  • the electrode is characterized in that it also comprises an intermediate layer of a metal chosen from the group consisting of rhodium, ruthenium, molybdenum, iridium, rhenium, tungsten and palladium.
  • a metal chosen from the group consisting of rhodium, ruthenium, molybdenum, iridium, rhenium, tungsten and palladium.
  • the metal of this layer being deposited directly on the metal support, preferably by electrolysis.
  • an intermediate layer according to the invention forms a barrier between the copper and the antimony sufficiently conductive to allow the deposition of the upper layer by electrolytic means.
  • this intermediate layer is a rhodium layer comprised between a metallic support made of copper-beryllium, and a layer made of an alkaline antimony compound.
  • a metallic support for example made of copper-beryllium, referenced 1 in FIG. 1, is covered with a first intermediate layer 2, with a metal chosen from the group, formed by rhodium, ruthenium, molybdenum, iridium , rhenium, tungsten and palladium, with a thickness substantially between 0.1 / um and 1 / um, and a second layer 3 of antimony, activated at least in its surface region 4 by forming alkaline antimony compounds, with a high secondary emission coefficient, for example a compound of antimony and cesium (Sb Cs3), sodium (Sb Na 3 ), potassium (Sb K 3 ) or rubidium (Sb Rb3); this region 4 having a thickness of the order of a few hundred Angstroms.
  • a metal chosen from the group, formed by rhodium, ruthenium, molybdenum, iridium , rhenium, tungsten and palladium, with a thickness substantially between 0.1 / um
  • the support 1 is necessarily metallic, because it must be brought to a certain voltage, so as to accelerate the electrons coming from a lower dynode. In addition, it must not have magnetic properties, it must be able to be evacuated (which excludes aluminum) and finally it must be formable from a sheet of metal and not be expensive. These criteria make it possible to retain several metals or alloys, preferably copper-beryllium, but also nickel ...
  • the first intermediate layer 2 plays the role of a barrier layer between on the one hand the metal support and on the other hand the emissive layer.
  • the metals capable of fulfilling this function are typically the noble metals which are not oxidizable and which practically do not react with the other elements.
  • the Applicant has selected (with the exception of platinum which reacts with copper), those which are electrolysable: the group selected is then constituted by rhodium, ruthenium, molybdenum, iridium, rhenium, tungsten and palladium.
  • rhodium because palladium reacts weakly with copper and ruthenium is more difficult to implement, in the form of an electrolysable bath, with a optimal temperature around 70 or 80 ° C, which results in significant water evaporation.
  • the deposition of these layers can be done by any means (vacuum evaporation, sputtering, etc.) but preferably it is carried out electrolytically, using a solution of adequate electrolyte. Indeed, this route is easily industrializable and therefore less expensive for the deposition of a layer of a material. However, electrolysis is only possible if the object has a relatively low surface resistance (which is not the case, in the presence of an oxide layer on the surface).
  • This electrolytic deposition is therefore carried out directly on the metallic support of non-oxidized copper-beryllium, by the usual route, namely immersion in an adequate electrolyte solution, brought to a suitable temperature generally specified by the producing firm, and connected to the negative terminal of a current generator, the other terminal of which is connected for example to a platinum electrode.
  • a layer with a thickness of the order of a few hundred Angstroms is then deposited, by establishing a current with a density close to 2A / dm 2 , for a time of 4 to 8 seconds (on average ) at room temperature.
  • the antimony layer is then exposed to vapors of alkaline elements - generally cesium and / or potassium - produced in an enclosure subjected to a fairly high vacuum, using a dichromate generator using the Joule effect.
  • the antimony layer and the enclosure are heated to a temperature substantially between 130 and 150 ° C, so as to accelerate this chemical reaction and to avoid condensation of the alkaline element on cold regions of the enclosure. It then occurs, at least in a surface region 4, of a thickness of a few hundred Angstroms, the formation of alkaline antimony compounds, having a high coefficient of secondary emission.
  • FIG. 2 is a perspective view of a particular dynode, the geometry of which is adapted to the position and the adjustment of the potentials, so that the electrons emitted by a lower dynode are best captured.
  • This geometry is not in itself limiting of the invention and is given here only by way of example, while there are multiple forms of dynodes on the market.
  • FIG. 3 represents a diagram of a type of photomultiplier, with semi-transparent photocathode at the end.
  • the incident light strikes a photocathode 10, which emits electrons which are focused in the central orifice of an electrode 11, and which then fall on a first dynode 12, having a high secondary emission coefficient 6.
  • a photocathode 10 which emits electrons which are focused in the central orifice of an electrode 11 and which then fall on a first dynode 12, having a high secondary emission coefficient 6.
  • For an electron incident there are al6 emitted electrons, which are received, thanks to an appropriate geometry and an increasing potential, on a second dynode, the phenomenon continuing from side to side.

Landscapes

  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)

Abstract

Electrode comprising a metal base (1) and a layer (3) with high secondary emission coefficient, made from an alkaline compound of antimony, notable in that it also comprises an intermediate layer (2) acting as a barrier layer, made from a material selected from the group formed by rhodium, ruthenium, molybdenum, iridium, rhenium, tungsten and palladium. These various layers are preferably deposited electrolytically. These secondary emission electrodes find application in photomultiplier tubes. Application: scintillation measurement, spectrophotometry. <IMAGE>

Description

L'invention concerne une électrode à émission secondaire, comprenant très généralement au moins un support métallique et une couche à fort coefficient d'émission secondaire en un composé alcalin d'antimoine. Une telle électrode est connue de l'art antérieur, et l'on citera pour exemple le brevet français 1.128.707 au nom de la Demanderesse. L'invention trouve son application dans la fabrication des tubes photomultiplicateurs, pour des utilisations diverses, en particulier pour des mesures de scintillation (recherche ou médecine nucléaire...), ou pour la spectrophotométrie (analyse d'image...).The invention relates to a secondary emission electrode, very generally comprising at least one metallic support and a layer with a high secondary emission coefficient of an alkaline antimony compound. Such an electrode is known from the prior art, and we will cite for example the French patent 1,128,707 in the name of the Applicant. The invention finds its application in the manufacture of photomultiplier tubes, for various uses, in particular for scintillation measurements (research or nuclear medicine, etc.), or for spectrophotometry (image analysis, etc.).

Un photomultiplicateur est un tube qui groupe dans une même ampoule, une cellule photoélectrique et un amplificateur de courant, utilisant l'émission secondaire d'électrodes (dynodes) portées à des potentiels électriques croissants. Le gain de l'amplificateur est lié directement au nombre de dynodes et à leur coefficient d'émission secondaire.A photomultiplier is a tube which groups in a single bulb, a photoelectric cell and a current amplifier, using the secondary emission of electrodes (dynodes) brought to increasing electrical potentials. The gain of the amplifier is directly related to the number of dynodes and their secondary emission coefficient.

Initialement, lesdynodes étaient réalisées entre autres en alliage cuivre et béryllium (2 "o ) et présentaient un coefficient d'émission secondaire de l'ordre de 4, pour des électrons accélérés sous 100 volts.Initially, the dynodes were made inter alia from copper and beryllium alloy (2 "o) and had a secondary emission coefficient of the order of 4, for electrons accelerated at 100 volts.

Afin de réaliser des électrodes présentant un meilleur coefficient d'émission secondaire, il est connu de l'art antérieur de déposer sur un substrat métallique quelconque, une couche d'antimoine, par divers procédés de dépôt, tels que l'évaporation, la pulvérisation cathodique, ou l'électrolyse, puis d'activer ce matériau par évaporation sous vide d'éléments alcalins, par exemple du césium, du potassium ou du rubidium, à partir d'un générateur au bichromate à effet Joule et formation, au moins dans la région superficielle de la couche d'antimoine, de divers composés alcalins (par exemple Sb Cs3, SbK3...) ou même bi-alcalins (Sb CS2 K, SbK2 Cs...) , ces couches présentant alors un coefficient d'émission secondaire de l'ordre de 5,5 (dans le cas de Sb Cs3), dans les mêmes conditions.In order to produce electrodes having a better secondary emission coefficient, it is known from the prior art to deposit on any metallic substrate, a layer of antimony, by various deposition methods, such as evaporation, spraying cathodic, or electrolysis, then activate this material by vacuum evaporation of alkaline elements, for example cesium, potassium or rubidium, from a dichromate effect generator Joule and formation, at least in the surface region of the antimony layer, of various alkaline compounds (for example Sb Cs 3 , SbK3 ...) or even bi-alkali (Sb C S2 K, SbK 2 Cs ... ), these layers then having a secondary emission coefficient of the order of 5.5 (in the case of Sb Cs3), under the same conditions.

Cependant, alors que le substrat métallique utilisé habituellement est, pour des raisons historiques, en cuivre-béryllium, et que la couche à fort coefficient d'émission secondaire est en un composé alcalin d'antimoine, il se produit une réaction entre le cuivre et l'antimoine qui dégrade fortement les propriétés émissives de ladite couche, par suite de la formation d'un alliage entre le cuivre et l'antimoine.However, while the metal substrate usually used is, for historical reasons, copper-beryllium, and the layer with a high secondary emission coefficient is an alkaline antimony compound, a reaction takes place between the copper and antimony which strongly degrades the emissive properties of said layer, as a result of the formation of an alloy between copper and antimony.

L'invention a pour but de pallier cet inconvénient.The invention aims to overcome this drawback.

Il est connu aussi de l'art antérieur, notamment du brevet des Etats-Unis d'Amérique 2.639.963, délivré le 26 Mai 1953, des électrodes à émission secondaire, comprenant très généralement un support métallique, une couche intermédiaire et une couche à fort coefficient d'émission secondaire. Mais, d'une part la couche émissive est en un carbonate d'un métal alcalin, et d'autre part la couche intermédiaire joue un rôle important en accroissant l'émission secondaire de la couche supérieure.It is also known from the prior art, in particular from patent of the United States of America 2,639,963, issued on May 26, 1953, electrodes with secondary emission, very generally comprising a metallic support, an intermediate layer and a layer with high secondary emission factor. However, on the one hand the emissive layer is made of an alkali metal carbonate, and on the other hand the intermediate layer plays an important role in increasing the secondary emission of the upper layer.

Selon la présente invention, l'électrode est caractérisée en ce qu'elle comprend également une couche intermédiaire d'un métal choisi dans le groupe constitué par le rhodium, le ruthénium, le molybdène, l'iridium, le rhénium, le tungstène et le palladium. Le métal de cette couche étant déposé directement sur le support métallique, préférentiellement par électrolyse.According to the present invention, the electrode is characterized in that it also comprises an intermediate layer of a metal chosen from the group consisting of rhodium, ruthenium, molybdenum, iridium, rhenium, tungsten and palladium. The metal of this layer being deposited directly on the metal support, preferably by electrolysis.

L'introduction d'une couche intermédiaire selon l'invention forme une barrière entre le cuivre et l'antimoine suffisamment conductrice pour permettre le dépôt de la couche supérieure par voie électrolytique.The introduction of an intermediate layer according to the invention forms a barrier between the copper and the antimony sufficiently conductive to allow the deposition of the upper layer by electrolytic means.

Selon une réalisation préférentielle de l'invention, cette couche intermédiaire est une couche de rhodium comprise entre un support métallique en cuivre-béryllium, et une couche en un composé alcalin d'antimoine.According to a preferred embodiment of the invention, this intermediate layer is a rhodium layer comprised between a metallic support made of copper-beryllium, and a layer made of an alkaline antimony compound.

La description qui va suivre, en regard des dessins annexés donnés à titre non limitatif, permettra de mieux comprendre comment l'invention peut être réalisée.

  • La figure 1 représente la succession de couches composant l'électrode à émission secondaire.
  • La figure 2 représente une géométrie particulière d'électrode (dynode) et
  • la figure 3 représente un schéma d'un tube photomultiplicateur, comprenant de telles dynodes.
The description which follows, with reference to the appended drawings given without limitation, will allow a better understanding of how the invention can be implemented.
  • FIG. 1 represents the succession of layers making up the secondary emission electrode.
  • FIG. 2 represents a particular geometry of electrode (dynode) and
  • FIG. 3 represents a diagram of a photomultiplier tube, comprising such dynodes.

Un support métallique par exemple en cuivre-béryllium, référencé 1 à la figure 1, est recouvert d'une première couche intermédiaire 2, d'un métal choisi dans le groupe, formé par le rhodium, le ruthénium, le molybdène, l'iridium, le rhénium, le tungstène et le palladium, d'une épaisseur comprise sensiblement entre 0,1 /um et 1 /um, et d'une seconde couche 3 d'antimoine, activé au moins en sa région superficielle 4 par la formation de composés alcalins d'antimoine, présentant un fort coefficient d'émission secondaire, par exemple un composé d'antimoine et de césium (Sb Cs3), de sodium (Sb Na3), de potassium (Sb K3) ou de rubidium (Sb Rb3) ; cette région 4 présentant une épaisseur de l'ordre de quelques centaines d'Angstroms.A metallic support, for example made of copper-beryllium, referenced 1 in FIG. 1, is covered with a first intermediate layer 2, with a metal chosen from the group, formed by rhodium, ruthenium, molybdenum, iridium , rhenium, tungsten and palladium, with a thickness substantially between 0.1 / um and 1 / um, and a second layer 3 of antimony, activated at least in its surface region 4 by forming alkaline antimony compounds, with a high secondary emission coefficient, for example a compound of antimony and cesium (Sb Cs3), sodium (Sb Na 3 ), potassium (Sb K 3 ) or rubidium (Sb Rb3); this region 4 having a thickness of the order of a few hundred Angstroms.

Le support 1 est nécessairement métallique, car il doit être porté à une certaine tension, de manière à accélérer les électrons provenant d'une dynode inférieure. En outre, il ne doit pas posséder de propriétés magnétiques, il doit pouvoir être mis sous vide (ce qui exclut l'aluminium) et enfin il doit être formable à partir d'une feuille de métal et ne pas être coûteux. Ces critères permettent de retenir plusieurs métaux ou alliages, préférentiellement le cuivre-béryllium, mais également le nickel...The support 1 is necessarily metallic, because it must be brought to a certain voltage, so as to accelerate the electrons coming from a lower dynode. In addition, it must not have magnetic properties, it must be able to be evacuated (which excludes aluminum) and finally it must be formable from a sheet of metal and not be expensive. These criteria make it possible to retain several metals or alloys, preferably copper-beryllium, but also nickel ...

La première couche intermédiaire 2, joue le rôle d'une couche barrière entre d'une part le support métallique et d'autre part la couche émissive. Les métaux, susceptibles de remplir cette fonction, sont typiquement les métaux nobles qui ne sont pas oxydables et qui ne réagissent pratiquement pas avec les autres éléments. Parmi ceux-ci, la Demanderesse a sélectionné (à l'exception du platine qui réagit avec le cuivre), ceux qui sont électrolysables : le groupe retenu est alors cons- titué par le rhodium, le ruthénium, le molybdène, l'iridium, le rhénium, le tungstène et le palladium. Mais en vue de réaliser le meilleur mode de réalisation, il est préférable d'utiliser le rhodium, car le palladium réagit faiblement avec le cuivre et le ruthénium est plus difficile à mettre en oeuvre, sous la forme d'un bain électrolysable, avec une température optimale vers 70 ou 80°C, ce qui entraîne une évaporation importante d'eau.The first intermediate layer 2 plays the role of a barrier layer between on the one hand the metal support and on the other hand the emissive layer. The metals capable of fulfilling this function are typically the noble metals which are not oxidizable and which practically do not react with the other elements. Among these, the Applicant has selected (with the exception of platinum which reacts with copper), those which are electrolysable: the group selected is then constituted by rhodium, ruthenium, molybdenum, iridium, rhenium, tungsten and palladium. But in order to achieve the best embodiment, it is preferable to use rhodium, because palladium reacts weakly with copper and ruthenium is more difficult to implement, in the form of an electrolysable bath, with a optimal temperature around 70 or 80 ° C, which results in significant water evaporation.

Le dépôt de ces couches (rhodium, antimoine, etc...) peut se faire par tous moyens (évaporation sous vide, pulvérisation cathodique...) mais préférentiellement, il est effectué par voie électrolytique, au moyen d'une solution d'électrolyte adéquate. En effet, cette voie est aisément industrialisable et donc moins onéreuse pour le dépôt d'une couche d'un matériau. Mais, l'électrolyse n'est possible que si l'objet présente une résistance de surface relativement faible (ce qui n'est pas le cas, en présence d'une couche d'oxyde en surface). Ce dépôt par voie électrolytique est donc effectué directement sur le support métallique de cuivre-beryllium non oxydé, par la voie usuelle, à savoir immersion dans une solution d'électrolyte adéquate, portée à une température convenable généralement spécifiée par la firme productrice, et relié à la borne négative d'un générateur de courant, dont l'autre borne est reliée par exemple à une électrode de platine.The deposition of these layers (rhodium, antimony, etc.) can be done by any means (vacuum evaporation, sputtering, etc.) but preferably it is carried out electrolytically, using a solution of adequate electrolyte. Indeed, this route is easily industrializable and therefore less expensive for the deposition of a layer of a material. However, electrolysis is only possible if the object has a relatively low surface resistance (which is not the case, in the presence of an oxide layer on the surface). This electrolytic deposition is therefore carried out directly on the metallic support of non-oxidized copper-beryllium, by the usual route, namely immersion in an adequate electrolyte solution, brought to a suitable temperature generally specified by the producing firm, and connected to the negative terminal of a current generator, the other terminal of which is connected for example to a platinum electrode.

Ainsi, pour le dépôt d'une couche de rhodium sur un support de cuivre-beryllium, il convient d'utiliser une solution aqueuse de sulfate de rhodium, en milieu sulfurique (ph-1), avec une quantité d'ions rhodium voisine de 5 g/litre. Une telle solution se trouve commercialisée par la Société ENGELHARD Industries , sous la référence "Rhodium Electrolytique brillant S 100", et par la Société Continentale PARKER, sous la référence "Bain rhodium brillant T30". Le dépôt d'une couche de 0,25/um, nécessite l'établissement d'un courant d'une densité voisine de 1 A/dm2 pendant environ deux minutes à une température comprise entre 30 et 40°C. Des bains d'électrolytes, pour le dépôt du métal choisi dans le groupe sont également disponibles chez les mêmes fournisseurs.Thus, for the deposition of a layer of rhodium on a copper-beryllium support, it is advisable to use an aqueous solution of rhodium sulphate, in sulfuric medium (ph-1), with an amount of rhodium ions close to 5 g / liter. Such a solution is marketed by the company ENGELHARD Industries, under the reference "Bright Rhodium Electrolytic S 100", and by the Continental Company PARKER, under the reference "Bright rhodium bath T30". The deposition of a 0.25 / μm layer requires the establishment of a current with a density close to 1 A / dm 2 for approximately two minutes at a temperature between 30 and 40 ° C. Electrolyte baths for depositing the metal chosen from the group are also available from the same suppliers.

De même , pour le dépôt de la couche supérieure d'antimoine il est avantageux d'utiliser une solution aqueuse de chlorure d'antimoine (Sb C1 3), en milieu chlorhydrique, avec une quantité d'ions antimoine voisine de 20 g/litre. On dépose alors une couche d'une épaisseur de l'ordre de quelques centaines d'Angstrëms,par l'établissement d'un courant d'une densité voisine de 2A/dm2, pendant un temps de 4 à 8 secondes (en moyenne) à la température ambiante.Similarly, for the deposition of the upper layer of antimony it is advantageous to use an aqueous solution of antimony chloride (Sb C1 3 ), in hydrochloric medium, with an amount of antimony ions close to 20 g / liter . A layer with a thickness of the order of a few hundred Angstroms is then deposited, by establishing a current with a density close to 2A / dm 2 , for a time of 4 to 8 seconds (on average ) at room temperature.

La couche d'antimoine est ensuite exposée, à des vapeurs d'éléments alcalins- généralement du césium et/ou du potassium, - produite dans une enceinte soumise à un vide assez poussé, au moyen d'un générateur au bichromate par effet Joule. Il se produit une réaction chimique entre l'élément alcalin et l'antimoine, qui augmente avec la température. La couche d'antimoine et l'enceinte sont chauffées à une température sensiblement comprise entre 130 et 150°C, de manière à accélérer cette réaction chimique et à éviter la condensation de l'élément alcalin sur des régions froides de l'enceinte. Il se produit alors, au moins dans une région superficielle 4, d'une épaisseur de quelques centaines d'Angströms,la formation de composés alcalins d'antimoine, présentant un fort coefficient d'émission secondaire.The antimony layer is then exposed to vapors of alkaline elements - generally cesium and / or potassium - produced in an enclosure subjected to a fairly high vacuum, using a dichromate generator using the Joule effect. There is a reaction chemical between the alkaline element and antimony, which increases with temperature. The antimony layer and the enclosure are heated to a temperature substantially between 130 and 150 ° C, so as to accelerate this chemical reaction and to avoid condensation of the alkaline element on cold regions of the enclosure. It then occurs, at least in a surface region 4, of a thickness of a few hundred Angstroms, the formation of alkaline antimony compounds, having a high coefficient of secondary emission.

La figure 2 est une vue en perspective d'une dynode particulière, dont la géométrie est adaptée à la position et à l'ajustage des potentiels, de telle manière que les électrons émis par une dynode inférieure soient le mieux captés. Cette géométrie n'est pas limitative en elle-même de l'invention et n'est donnée ici qu'à titre d'exemple, alors qu'il existe de multiples formes de dynodes commercialisées.FIG. 2 is a perspective view of a particular dynode, the geometry of which is adapted to the position and the adjustment of the potentials, so that the electrons emitted by a lower dynode are best captured. This geometry is not in itself limiting of the invention and is given here only by way of example, while there are multiple forms of dynodes on the market.

La figure 3 représente un schéma d'un type de photomultiplicateur , à photocathode semi-transparente en bout. La lumière incidente vient frapper une photocathode 10, qui émet des électrons qui sont focalisés dans l'orifice central d'une électrode 11, et qui tombent alors sur une première dynode 12, ayant un coefficient d'émission secondaire élevé 6. Pour un électron incident, y a alôrs6 électrons émis, qui sont reçus, grâce à une géométrie appropriée et un potentiel croissant, sur une deuxième dynode, le phénomène se poursuivant de part en part.FIG. 3 represents a diagram of a type of photomultiplier, with semi-transparent photocathode at the end. The incident light strikes a photocathode 10, which emits electrons which are focused in the central orifice of an electrode 11, and which then fall on a first dynode 12, having a high secondary emission coefficient 6. For an electron incident, there are al6 emitted electrons, which are received, thanks to an appropriate geometry and an increasing potential, on a second dynode, the phenomenon continuing from side to side.

Ainsi, si n est le nombre total de dynodes, le gain de l'amplificateur ainsi constitué vaut :

Figure imgb0001
Thus, if n is the total number of dynodes, the gain of the amplifier thus constituted is worth:
Figure imgb0001

Il est alors évident que pour améliorer le gain G, on peut augmenter le nombre de dynodes mais également améliorer le coefficient d'émission secondaire, conformément à l'esprit de la présente invention, telle que revendiquée ci-après.It is then obvious that to improve the gain G, it is possible to increase the number of dynodes but also to improve the secondary emission coefficient, in accordance with the spirit of the present invention, as claimed below.

Claims (5)

1. Electrode à émission secondaire comprenant au moins un support métallique (1) et une couche à fort coefficient d'émission secondaire (3), en un composé alcalin d'antimoine, caractérisée en ce qu'elle comprend également une couche intermédiaire (2) d'un métal choisi dans le groupe constitué par le rhodium, le ruthénium, le molybdène, l'iridium, le rhénium, le tungstène et le palladium.1. Secondary emission electrode comprising at least one metallic support (1) and a layer with a high secondary emission coefficient (3), made of an alkaline antimony compound, characterized in that it also comprises an intermediate layer (2 ) of a metal chosen from the group consisting of rhodium, ruthenium, molybdenum, iridium, rhenium, tungsten and palladium. 2. Electrode selon la revendication 1, caractérisée en ce que le métal de la couche intermédiaire (2) est le rhodium.2. Electrode according to claim 1, characterized in that the metal of the intermediate layer (2) is rhodium. 3. Electrode selon la revendication 1, caractérisée en-ce que le support métallique (1) est en un alliage cuivre-béryllium (2 %)3. Electrode according to claim 1, characterized in that the metal support (1) is made of a copper-beryllium alloy (2%) 4. Electrode selon l'une des revendications 1 à 3, caractérisée en ce que la couche à fort coefficient d'émission secondaire (3) comprend au moins un élément choisi dans le groupe formé par le césium, le sodium, le potassium et le rubidium.4. Electrode according to one of claims 1 to 3, characterized in that the layer with a high secondary emission coefficient (3) comprises at least one element chosen from the group formed by cesium, sodium, potassium and rubidium. 5. Photomultiplicateur comportant au moins une électrode à émission secondaire, selon l'une des revendications 1 à 4.5. Photomultiplier comprising at least one secondary emission electrode, according to one of claims 1 to 4.
EP80200903A 1979-10-03 1980-09-26 Secondary-emission electrode, particularly for a photomultiplier Withdrawn EP0026949A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7924639A FR2466851A1 (en) 1979-10-03 1979-10-03 SECONDARY EMISSION ELECTRODE, IN PARTICULAR FOR A PHOTOMULTIPLIER
FR7924639 1979-10-03

Publications (1)

Publication Number Publication Date
EP0026949A1 true EP0026949A1 (en) 1981-04-15

Family

ID=9230274

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80200903A Withdrawn EP0026949A1 (en) 1979-10-03 1980-09-26 Secondary-emission electrode, particularly for a photomultiplier

Country Status (3)

Country Link
EP (1) EP0026949A1 (en)
JP (1) JPS5659446A (en)
FR (1) FR2466851A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2508232A1 (en) * 1981-06-19 1982-12-24 Hyperelec Photo-electrode for electron photomultiplier tube - has thin conductive layer forming cylindrical portion between photocathode and accelerating electrode to correct focussing
FR2644288A1 (en) * 1989-03-13 1990-09-14 Asulab Sa METHOD FOR MANUFACTURING A DYNODE AND DYNODE MANUFACTURED ACCORDING TO THIS METHOD
EP1329939A1 (en) * 2000-07-27 2003-07-23 Hamamatsu Photonics K.K. Photomultiplier

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB559591A (en) * 1942-07-17 1944-02-25 Int Standard Electric Corp Improvements relating to secondary electron emissive electrodes
GB689966A (en) * 1948-04-05 1953-04-08 Sylvania Electric Prod Secondary-electron emitters and method of manufacture
FR1128707A (en) * 1955-07-07 1957-01-09 D Electronique Et De Physque A Improvements in the manufacturing process of secondary emission dynodes and said dynodes
FR2091148A5 (en) * 1970-05-05 1972-01-14 Rca Corp

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB559591A (en) * 1942-07-17 1944-02-25 Int Standard Electric Corp Improvements relating to secondary electron emissive electrodes
GB689966A (en) * 1948-04-05 1953-04-08 Sylvania Electric Prod Secondary-electron emitters and method of manufacture
FR1128707A (en) * 1955-07-07 1957-01-09 D Electronique Et De Physque A Improvements in the manufacturing process of secondary emission dynodes and said dynodes
FR2091148A5 (en) * 1970-05-05 1972-01-14 Rca Corp

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
RADIO ENGINEERING AND ELECTRONIC PHYSICS, Vol. 15, No. 2, Fevrier 1970, pages 360,361 Washington, U.S.A. G.B. STUCHINSKIY: "Inelastic Electron Reflection from Emitters of Cs3Sb and (Cs) Na2KSb" *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2508232A1 (en) * 1981-06-19 1982-12-24 Hyperelec Photo-electrode for electron photomultiplier tube - has thin conductive layer forming cylindrical portion between photocathode and accelerating electrode to correct focussing
FR2644288A1 (en) * 1989-03-13 1990-09-14 Asulab Sa METHOD FOR MANUFACTURING A DYNODE AND DYNODE MANUFACTURED ACCORDING TO THIS METHOD
EP0387615A1 (en) * 1989-03-13 1990-09-19 Asulab S.A. Process for manufacturing a dynode, and dynode produced according to this process
EP1329939A1 (en) * 2000-07-27 2003-07-23 Hamamatsu Photonics K.K. Photomultiplier
EP1329939A4 (en) * 2000-07-27 2005-01-19 Hamamatsu Photonics Kk Photomultiplier
US6927538B2 (en) 2000-07-27 2005-08-09 Hamamatsu Photonics K.K. Photomultiplier tube

Also Published As

Publication number Publication date
JPS5659446A (en) 1981-05-22
FR2466851B1 (en) 1982-09-03
FR2466851A1 (en) 1981-04-10

Similar Documents

Publication Publication Date Title
KR102029648B1 (en) Metal sheet for separators of polymer electrolyte fuel cells, and metal sheet for manufacturing the same
JP5136346B2 (en) X-ray device electrode
US7612384B2 (en) Reflective electrode for a semiconductor light emitting apparatus
FR2656337A1 (en) OXYGEN GENERATING ELECTRODE AND PROCESS FOR PREPARING THE SAME.
TWI320803B (en) Electrode material
US20060032757A1 (en) Activation of aluminum for electrodeposition or electroless deposition
WO2016166935A1 (en) Metal plate for use as separator of solid polymer fuel cell
FR2599050A1 (en) SUSTAINABLE ELECTRODES FOR ELECTROLYSIS WITH ANODE OXYGEN RELEASE AND PROCESS THEREOF
FR2599386A1 (en) SUSTAINABLE ELECTRODES FOR ELECTROLYSIS AND PROCESS FOR THEIR MANUFACTURE
KR20140066221A (en) Solar cell interconnector material, solar cell interconnector, and solar cell with interconnector
JPS61224234A (en) Film material of dinode for photo electric multiplier
US4079164A (en) Base metal plate for directly heated oxide cathode
EP0026949A1 (en) Secondary-emission electrode, particularly for a photomultiplier
US4260665A (en) Electron tube cathode and method for producing the same
JPH0544132B2 (en)
WO2018065478A1 (en) Improved contacts for a photovoltaic cell having two active faces
CH619492A5 (en) Process for the preparation of a substrate bearing a tin oxide coating
KR20090072900A (en) Electrode for cold-cathode fluorescent lamp
EP1451875B1 (en) Method for producing an imaging device
JP3241257B2 (en) Method for manufacturing electron-emitting device
FR2600177A1 (en) METHOD OF MANUFACTURING A RADIOLOGICAL IMAGE INTENSIFIER AND INTENSIFIER OF RADIOLOGICAL IMAGES THUS OBTAINED
EP1200973A1 (en) Improved oxide-coated cathode and method for making same
KR830002360B1 (en) Direct Oxide Cathode
JPH06293998A (en) Insoluble iridium oxide coated electrode and its production
BE443426A (en)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19810928

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: N.V. PHILIPS' GLOEILAMPENFABRIEKEN

Owner name: LABORATOIRES D'ELECTRONIQUE ET DE PHYSIQUE APPLIQU

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19830907

RIN1 Information on inventor provided before grant (corrected)

Inventor name: AUDIER, MARCEL

Inventor name: TRANCHART, JEAN-CLAUDE