EP0131339B1 - Electron multiplier element, electron multiplying device made up of this element and its application to a photomultiplier tube - Google Patents

Electron multiplier element, electron multiplying device made up of this element and its application to a photomultiplier tube Download PDF

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Publication number
EP0131339B1
EP0131339B1 EP84200994A EP84200994A EP0131339B1 EP 0131339 B1 EP0131339 B1 EP 0131339B1 EP 84200994 A EP84200994 A EP 84200994A EP 84200994 A EP84200994 A EP 84200994A EP 0131339 B1 EP0131339 B1 EP 0131339B1
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European Patent Office
Prior art keywords
multiplier
holes
plate
electron
auxiliary
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EP84200994A
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German (de)
French (fr)
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EP0131339A1 (en
Inventor
Gilbert Eschard
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HYPERELEC
Koninklijke Philips NV
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HYPERELEC
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J43/00—Secondary-emission tubes; Electron-multiplier tubes
    • H01J43/04—Electron multipliers
    • H01J43/06—Electrode arrangements
    • H01J43/18—Electrode arrangements using essentially more than one dynode
    • H01J43/22—Dynodes consisting of electron-permeable material, e.g. foil, grid, tube, venetian blind

Definitions

  • the present invention relates to an electron multiplier device comprising a parallel stack of N secondary emission multiplier elements of the “hole plate” type, each of which comprises a plate pierced with multiplier holes arranged in a regular plane network, each multiplier hole defining, on a first face of said plate, an inlet opening and, on the second face of the plate, an outlet opening smaller than the inlet opening. It also relates to a photomultiplier tube comprising a photocathode, at least one anode and an electron multiplier device according to the invention.
  • An electron multiplier device is known, for example, from French patent n ° 2 299 722.
  • This patent describes an electron multiplier device constituted by a stack of electron multiplier elements with secondary emission composed of two half-plates drilled with holes with concave walls so that, the half-plates being assembled, the corresponding holes of each half-plate form a single barrel-shaped hole.
  • the walls of these holes carry a layer of secondary emission material, the useful part of each single hole being constituted by the lower half-hole.
  • this type of known electron multiplier device has a drawback which resides in the fact that a certain number of incident electrons do not give rise to secondary emission because they pass directly through the multiplier holes without undergoing multiplication and that others reach the multiplier element in places from which the secondary electrons cannot be extracted, for example between two holes or outside the useful part of the holes.
  • the object of the present invention is to remedy this drawback by seeking to increase the collection efficiency of the multiplier elements.
  • the first plate offers the incident electrons a much larger useful multiplication surface than in the plates with known holes.
  • the second plate the holes of which, called auxiliary, substantially reproduce the shape of the outlet opening of the multiplier holes, serves as an accelerating electrode.
  • this configuration in which the multiplier elements are relatively far apart, has the advantage of a better collection of electrons between one multiplier element and the next.
  • a particular embodiment of the multiplier device according to the invention consists in that the multiplier and auxiliary holes of the (i + 1) th multiplier element are located opposite the multiplier and auxiliary holes of the i th multiplier element, so that the multiplier holes and auxiliary counterparts of the N multiplying elements constitute rectilinear channels whose direction is perpendicular to the faces of the N multiplying elements.
  • This embodiment has the advantage of allowing the formation of intensified images, when it is used in a tube of the image intensifier type, since the secondary electrons leaving a channel of the device come in principle only from the multiplication of incident electrons entering the same channel.
  • the multipliers and auxiliaries of (i + 1) th multiplier element are offset from the multiplier and auxiliary holes of the th multiplier element so that the homologous multiplier and auxiliary holes of the N multiplier elements constitute rectilinear channels whose direction makes an acute angle with the normal to the faces of the N multiplier elements.
  • a staggered structure of the multiplier holes ensures very good efficiency of the whole of the multiplier device according to the invention.
  • the outlet openings of the multiplier holes of the first plate are offset with respect to their inlet openings so that said multiplier holes are asymmetrical.
  • a device of multiplier elements with asymmetrical holes allows both good electronic performance and the possibility of image formation.
  • the advantage of having asymmetrical multiplier holes is also to spatially define the position of the useful multiplication part with respect to the exit opening of the multiplier holes and therefore to preferentially orient the trajectories of the secondary electrons.
  • the multiplier and auxiliary holes of the (i + 1 ) th multiplier element are offset from the multiplier and auxiliary holes of the th multiplier element so that the homologous multiplier and auxiliary holes of the N multiplier elements constitute channels describing a helix.
  • the electron multiplier device according to the invention can be used in a particularly advantageous manner in a photomultiplier tube comprising a photocathode and at least one anode.
  • said multiplier device is placed between the photocathode and the anode, and at least partially replaces the conventional dynodes.
  • This type of photomultiplier tube has many advantages: large collection surface, good linearity, speed and small footprint.
  • a particular photomultiplier tube comprising a plurality of adjacent coplanar anodes is remarkable in that said multiplier device is divided into a plurality of secondary multiplier devices separated by electron-tight partitions and perpendicular to the planes of the multiplier device, the multiplier device being placed, on the one hand, close to the photocathode so that the photoelectrons emitted by the photocathode portion located opposite the jth secondary multiplier device do not reach the (j + 1 ) th secondary device, and, on the other hand, in parallel at the anodes and in such a way that the watertight partitions are located opposite the separation zones of two consecutive anodes, so as to produce n secondary photomultiplier tubes in the same photomultiplier tube.
  • each secondary photomultiplier supplies an electrical signal proportional to the light information received by the corresponding photocathode element.
  • This kind of tube is well suited for the localization of nuclear particles, for example.
  • FIG. 1 shows, in section, an electron multiplier element 11 with secondary emission of the “hole plate” type.
  • this multiplier element is composed, on the one hand, of a first plate 12 pierced with holes 13, called multiplier holes, arranged in a regular plane network.
  • Each multiplier hole 13 defines, on a first face 14 of said first plate, an opening 15, called the inlet opening, larger than the opening 16, called the outlet opening, defined on the second face 17 of the first plate 12 , the inlet opening of each multiplier hole being substantially tangent to the inlet openings of the nearest neighbors of said multiplier hole.
  • the multiplier element 11 comprises a second plate 22 parallel to the first plate 12, also pierced with holes 23, called auxiliary holes, the opening 25 of which on a first face 24 of the second plate 22, located in look of the second face 17 of the first plate 12, is substantially equal to the opening 16 of the outlet of the multiplier holes 13 and smaller than the opening 26 of said auxiliary holes 23 defined on the second face 27 of the second plate 22.
  • said first 12 and second 22 plates are electrically isolated from each other, the second plate 22 being brought to a potential V1 greater than the potential VO of the first plate 12.
  • At least the first plate 12 is made of a material which can give rise to secondary emission such as a copper-beryllium alloy having undergone the conventional treatment: heating-migration of beryllium and oxidation. It can also be produced in an inexpensive material, such as mild steel, covered with secondary emission material: layer of oxidized copper-beryllium alloy or layer of manganese oxide.
  • the multiplier element 11 according to the invention offers incident electrons 60 on the side of the first face 14 of the first plate 12 a collection and multiplication surface. significantly larger.
  • the electrical insulation of the two plates 12 and 22 can be done, for example, using small glass balls 70, 100 to 200 ⁇ m in diameter sealed at the periphery of said plates.
  • FIG. 2 shows a top view of the first plate 12 of the multiplier element 11 in FIG. 1.
  • the inlet 15 and outlet 16 openings of the multiplier holes 13 are circular and said regular flat network is square .
  • FIG. 3 gives a first variant of the plate shown in FIG. 2 which makes it possible to increase the useful multiplication surface of the first plate.
  • the inlet 15 and outlet 16 openings of the multiplier holes 13 of the first plate 12 are circular and said regular plane network is hexagonal.
  • FIGS. 4 and 5 If one wishes to further increase the collection and multiplication efficiency of the first plate, one can refer to FIGS. 4 and 5 in which the inlet opening 15 of the multiplier holes 13 of the first plate 12 is substantially square , respectively hexagonal, and said regular plane network is square, respectively hexagonal.
  • Figs. 5 and 6 show a third variant of a multiplier element according to the invention in which the outlet openings 16 of the multiplier holes 13 of the first plate 12 are offset with respect to their inlet openings 15 so that said multiplier holes 13 are asymmetrical.
  • the realization of such multiplier elements is done by chemical attack on both sides of a metal plate through masks offset appropriately.
  • N 3 multiplier elements
  • the distance D between the second side 27 of the second plate 22 of the ith multiplier element and the first face 14 of the first plate 12 of the (i + 1) th multiplier element is greater than the distance d separating the first 12 and second 22 plates of the same multiplier element .
  • the second plate 22 of the ith multiplier element is at an electric potential V1 i identical to the electric potential VO (i + 1) of the first plate 12 of the (i + 1) th multiplier element.
  • the multiplier device according to the invention has better collection efficiency than in the known devices, due to the good collection efficiency of each multiplier element and also the effect of distance between two consecutive multiplier elements.
  • the multiplier elements are kept at distance D from each other by spacers 29 arranged at the periphery of the plates.
  • the multiplier 13 and auxiliary holes 23 of the (i + 1) th multiplier element are located opposite the multiplier and auxiliary holes of the i th multiplier element, so that the homologous multiplier and auxiliary holes N multiplying elements constitute rectilinear channels whose direction 30 is perpendicular to the faces of the N multiplying elements.
  • This embodiment of the multiplier device according to the invention offers the advantage of being able to be used in a tube of the image intensifier type since the secondary electrons leaving a channel of the device result from the multiplication of incident electrons 60 entering the same channel.
  • Fig. 8 shows in section an alternative embodiment of the multiplier device of FIG. 7, variant in which the multiplier 13 and auxiliary holes 23 of the (i + 1) th multiplier element are offset with respect to the multiplier and auxiliary holes of the ith multiplier element so that the homologous multiplier and auxiliary holes of the N multiplier elements constitute rectilinear channels whose direction 31 makes an acute angle with the normal 30 to the faces of the N multiplier elements.
  • This variant of execution makes it possible to increase the gain of the multiplier device according to the invention since incident electrons which would pass through a multiplier element at the center of a multiplier hole, therefore without multiplication, are then multiplied by the following multiplier element whereas 'they would not be in the embodiment of Figure 7.
  • the device shown can not be used for image formation because there is no one-to-one correspondence between a given multiplier hole of the 1st multiplier element and a multiplier hole of Nth and last multiplier element.
  • the multiplier 13 and auxiliary holes 23 of the (i + 1) th multiplier element are offset with respect to the multiplier and auxiliary holes of the ith multiplier element so that the homologous multiplier and auxiliary holes of the N multiplier elements constitute channels describing a helix.
  • FIG. 11 b shows a top view of a plate of a triangle-shaped multiplier element, the useful part of which is represented by the circle 80.
  • This plate has a tab 81 for electrical connection and is pierced with three holes 82 which allow assembling the plates of the multiplying elements using posts passing through the holes 82.
  • the helical offset is obtained by shifting the position of the three holes 82 in opposite directions after having determined the origins of the axes (x, y) by fixing pins which penetrate into multiplier or auxiliary holes in the central area 80.
  • the electron multiplier device according to the invention finds a particularly advantageous application to photomultiplier tubes.
  • the photomultiplier tube comprises a photocathode 41 and an anode 42; the multiplier device 40 according to the invention is placed between the photocathode 41 and the anode 42, the inlet opening 15 of the multiplier holes being oriented towards the photocathode 41.
  • the tube has a first dynode 43 which can be of large size, hence greater collection efficiency as well as better linearity, better speed and less bulk.
  • FIG. 13 shows, in section, another application of the invention to a photomultiplier tube comprising n adjacent anodes 42.
  • said multiplier device is divided into a plurality n of secondary multiplier devices separated by partitions 50 that are electron-tight and perpendicular to the planes of the multiplier device, the multiplier device being placed, on the one hand, near the photocathode of in such a way that the photoelectrons emitted by the photocathode position situated opposite the jth secondary multiplier device do not reach the (j:!: 1) th secondary device, and, on the other hand, parallel to the anodes 42 and in such a way that the watertight partitions 50 are located opposite the zones 51 of separation of two consecutive anodes 42, so as to produce n secondary photomultiplier tubes in the same photomultiplier tube.
  • Tubes of the type shown in FIG. 13 find advantageous use in nuclear physics because they allow precise localization of the particles detected.
  • the watertight partitions 50 can be produced in a

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  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Electron Tubes For Measurement (AREA)
  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Description

La présente invention concerne un dispositif multiplicateur d'électrons comportant un empilement parallèle de N éléments multiplicateurs à émission secondaire du type «plaque à trous», dont chacun comporte une plaque percée de trous multiplicateurs disposés selon un réseau plan régulier, chaque trou multiplicateur définissant, sur une première face de ladite plaque, une ouverture d'entrée et, sur la deuxième face de la plaque, une ouverture de sortie plus petite que l'ouverture d'entrée. Elle concerne également un tube photomultiplicateur comportant une photocathode, au moins une anode et un dispositif multiplicateur d'électrons selon l'invention.The present invention relates to an electron multiplier device comprising a parallel stack of N secondary emission multiplier elements of the “hole plate” type, each of which comprises a plate pierced with multiplier holes arranged in a regular plane network, each multiplier hole defining, on a first face of said plate, an inlet opening and, on the second face of the plate, an outlet opening smaller than the inlet opening. It also relates to a photomultiplier tube comprising a photocathode, at least one anode and an electron multiplier device according to the invention.

Un dispositif multiplicateur d'électrons est connu, par exemple, du brevet français n° 2 299 722. Ce brevet décrit un dispositif multiplicateur d'électrons constitué par un empilement d'éléments multiplicateurs d'électrons à émission secondaire composés de deux demi-plaques percées de trous à parois concaves de façon que, les demi-plaques étant rassemblées, les trous correspondants de chaque demi-plaque forment un trou unique en forme de tonneau. Les parois de ces trous portent une couche d'un matériau à émission secondaire, la partie utile de chaque trou unique étant constituée par le demi- trou inférieur.An electron multiplier device is known, for example, from French patent n ° 2 299 722. This patent describes an electron multiplier device constituted by a stack of electron multiplier elements with secondary emission composed of two half-plates drilled with holes with concave walls so that, the half-plates being assembled, the corresponding holes of each half-plate form a single barrel-shaped hole. The walls of these holes carry a layer of secondary emission material, the useful part of each single hole being constituted by the lower half-hole.

L'avantage d'une telle structure d'éléments multiplicateurs d'électrons est qu'elle permet, sous un encombrement réduit, la multiplication d'électrons incidents se présentant, au niveau de la plaque, sous la forme d'un faisceau large, par exemple un faisceau cylindrique, et ceci sans qu'il soit nécessaire d'utiliser une optique électronique de focalisation. D'autre part, une structure répétitive de faible pas se prête bien à la formation d'images intensifiées.The advantage of such a structure of electron multiplier elements is that it allows, under a reduced bulk, the multiplication of incident electrons appearing, at the level of the plate, in the form of a wide beam, for example a cylindrical beam, and this without the need to use electronic focusing optics. On the other hand, a repetitive structure of low pitch lends itself well to the formation of intensified images.

On connaît également de la demande de brevet français n° 2 226 749 et du brevet américain n° 3182 221, des dispositifs du type connu susmentionné, dont les éléments multiplicateurs, dits «plaques à trous», comportent chacun une plaque percés de trous multiplicateurs, disposés selon un réseau plan régulier, chaque trou multiplicateur définissant, sur une première face de ladite plaque, une ouverture d'entrée et sur la deuxième face de la plaque, une ouverture de sortie plus petite que l'ouverture d'entrée.Also known from French patent application No. 2,226,749 and American patent No. 3,182,221, devices of the aforementioned known type, the multiplier elements of which, called “hole plates”, each include a plate pierced with multiplier holes , arranged in a regular plane network, each multiplier hole defining, on a first face of said plate, an inlet opening and on the second face of the plate, an outlet opening smaller than the inlet opening.

Toutefois, ce type de dispositifs multiplicateurs d'électrons connus présente un inconvénient qui réside dans le fait qu'un certain nombre d'électrons incidents ne donnent pas lieu à émission secondaire parce qu'ils traversent directement les trous multiplicateurs sans subir de multiplication et que d'autres atteignent l'élément multiplicateur en des endroits d'où les électrons secondaires ne peuvent être extraits, par exemple entre deux trous ou en dehors de la partie utile des trous.However, this type of known electron multiplier device has a drawback which resides in the fact that a certain number of incident electrons do not give rise to secondary emission because they pass directly through the multiplier holes without undergoing multiplication and that others reach the multiplier element in places from which the secondary electrons cannot be extracted, for example between two holes or outside the useful part of the holes.

Le but de la présente invention est de remédier à cet inconvénient en cherchant à augmenter l'efficacité de collection des éléments multiplicateurs.The object of the present invention is to remedy this drawback by seeking to increase the collection efficiency of the multiplier elements.

En effet, selon la présente invention, un dispositif multiplicateur d'électrons conforme au préambule est notamment remarquable en ce que

  • - chaque élément multiplicateur comprend une deuxième plaque, parallèle à la susdite plaque, dite première plaque, et également percée de trous, dits trous auxiliaires, dont l'ouverture sur une première face de la deuxième plaque, située en regard de la deuxième face de la première plaque, est sensiblement identique à l'ouverture de sortie des trous multiplicateurs et plus petite que l'ouverture desdits trous auxiliaires définie sur la deuxième face de la deuxième plaque, en ce que
  • - l'ouverture d'entrée de chaque trou multiplicateur est sensiblement tangente aux ouvertures d'entrée des plus proches voisins dudit trou multiplicateur, en ce que
  • - les première et deuxième plaques de chaque élément multiplicateur sont isolées électriquement l'une de l'autre, en ce que
  • - la distance entre la deuxième face de la deuxième plaque du ième multiplicateur et la première face de la première plaque du (i+1)ème élément multiplicateur est plus grande que la distance séparant les première et deuxième plaques d'un même élément multiplicateur, et en ce que
  • - i désignant le rang occupé par un élément multiplicateur dans l'empilement en partant de la face d'entrée des électrons primaires, il comprend, pour toutes les valeurs de i, des moyens permettant de porter la deuxième plaque du ième élément multiplicateur à un potentiel électrique Vli supérieur au potentiel VOi de la première plaque dudit ième élément multiplicateur, lequel potentiel Vli est, pour les valeurs de i n'excédant pas N-1, identique au potentiel électrique VO(i+ 1) de la première plaque du (i+1)ème élément multiplicateur.
Indeed, according to the present invention, an electron multiplier device in accordance with the preamble is particularly remarkable in that
  • each multiplier element comprises a second plate, parallel to the aforesaid plate, called the first plate, and also pierced with holes, called auxiliary holes, the opening of which on a first face of the second plate, located opposite the second face of the first plate, is substantially identical to the outlet opening of the multiplier holes and smaller than the opening of said auxiliary holes defined on the second face of the second plate, in that
  • the inlet opening of each multiplier hole is substantially tangent to the inlet openings of the nearest neighbors of said multiplier hole, in that
  • - the first and second plates of each multiplier element are electrically isolated from each other, in that
  • the distance between the second face of the second plate of the ith multiplier and the first face of the first plate of the (i + 1) th multiplier element is greater than the distance separating the first and second plates of the same multiplier element, and in that
  • - i designating the rank occupied by a multiplier element in the stack starting from the input face of the primary electrons, it comprises, for all the values of i, means making it possible to bring the second plate of the ith multiplier element to a electric potential V l i greater than the potential VOi of the first plate of said ith multiplying element, which potential V l i is, for the values of i not exceeding N-1, identical to the electric potential VO (i + 1) of the first (i + 1) th multiplier element plate.

Ainsi, du fait que les ouvertures d'entrée sont quasi tangentes et que les trous multiplicateurs présentent une structure ouverte en demi-tonneau, la première plaque offre aux électrons incidents une surface utile de multiplication beaucoup plus grande que dans les plaques à trous connues. La deuxième plaque, dont les trous, dits auxiliaires, reproduisent sensiblement la forme de l'ouverture de sortie des trous multiplicateurs, sert d'éléctrode accélératrice.Thus, because the inlet openings are almost tangent and the multiplier holes have an open structure in a half barrel, the first plate offers the incident electrons a much larger useful multiplication surface than in the plates with known holes. The second plate, the holes of which, called auxiliary, substantially reproduce the shape of the outlet opening of the multiplier holes, serves as an accelerating electrode.

De même, cette configuration, dans laquelle les éléments multiplicateurs sont relativement éloignés, présente l'avantage d'une meilleure collection des électrons entre un élément multiplicateur et le suivant.Likewise, this configuration, in which the multiplier elements are relatively far apart, has the advantage of a better collection of electrons between one multiplier element and the next.

Un mode particulier de réalisation du dispositif multiplicateur selon l'invention consiste en ce que les trous multiplicateurs et auxiliaires du (i+1)ème élément multiplicateur sont situés en regard des trous multiplicateurs et auxiliaires du ième élément multiplicateur, de façon que les trous multiplicateurs et auxiliaires homologues des N éléments multiplicateurs constituent des canaux rectilignes dont la direction est perpendiculaire aux faces des N éléments multiplicateurs. Ce mode de réalisation présente l'avantage de permettre la formation d'images intensifiées, quand il est utilisé dans un tube du type intensifi- cateur d'images, puisque les électrons secondaires sortant d'un canal du dispositif ne proviennent en principe que de la multiplication des électrons incidents pénétrant dans le même canal.A particular embodiment of the multiplier device according to the invention consists in that the multiplier and auxiliary holes of the (i + 1) th multiplier element are located opposite the multiplier and auxiliary holes of the i th multiplier element, so that the multiplier holes and auxiliary counterparts of the N multiplying elements constitute rectilinear channels whose direction is perpendicular to the faces of the N multiplying elements. This embodiment has the advantage of allowing the formation of intensified images, when it is used in a tube of the image intensifier type, since the secondary electrons leaving a channel of the device come in principle only from the multiplication of incident electrons entering the same channel.

Par contre si l'on désire augmenter encore le gain du dispositif selon l'invention, mais en renonçant à la possibilité de formation d'images lorsque les trous multiplicateurs sont symétriques, il est prévu que les multiplicateurs et auxiliaires du (i+1)ème élément multiplicateur sont décalés par rapport aux trous multiplicateurs et auxiliaires du ième élément multiplicateur de façon que les trous multiplicateurs et auxiliaires homologues des N éléments multiplicateurs constituent des canaux rectilignes dont la direction fait un angle aigu avec la normale aux faces des N éléments multiplicateurs. En particulier, une structure en quinconce des trous multiplicateurs assure une très bonne efficacité de l'ensemble du dispositif multiplicateur selon l'invention.On the other hand, if it is desired to further increase the gain of the device according to the invention, but by renouncing the possibility of image formation when the multiplier holes are symmetrical, it is expected that the multipliers and auxiliaries of (i + 1) th multiplier element are offset from the multiplier and auxiliary holes of the th multiplier element so that the homologous multiplier and auxiliary holes of the N multiplier elements constitute rectilinear channels whose direction makes an acute angle with the normal to the faces of the N multiplier elements. In particular, a staggered structure of the multiplier holes ensures very good efficiency of the whole of the multiplier device according to the invention.

On prévoit également que les ouvertures de sortie des trous multiplicateurs de la première plaque sont décalées par rapport à leurs ouvertures d'entrée de sorte que lesdits trous multiplicateurs sont dissymétriques. Notons qu'un dispositif d'éléments multiplicateurs à trous dissymétriques permet à la fois un bon rendement électronique et la possibilité de formation d'images. L'avantage de disposer de trous multiplicateurs dissymétriques est également de définir spatiale- ment la position de la partie utile de multiplication par rapport à l'ouverture de sortie des trous multiplicateurs et donc d'orienter de façon préférentielle les trajectoires des électrons secondaires.It is also provided that the outlet openings of the multiplier holes of the first plate are offset with respect to their inlet openings so that said multiplier holes are asymmetrical. Note that a device of multiplier elements with asymmetrical holes allows both good electronic performance and the possibility of image formation. The advantage of having asymmetrical multiplier holes is also to spatially define the position of the useful multiplication part with respect to the exit opening of the multiplier holes and therefore to preferentially orient the trajectories of the secondary electrons.

Dans le but d'éviter le retour d'ions et de lumière vers la photocathode à travers lesdits canaux rectilignes, lorsque le dispositif selon l'invention est incorporé à un tube photomultiplicateur, on envisage que les trous multiplicateurs et auxiliaires du (i+1)ème élément multiplicateur sont décalés par rapport aux trous multiplicateurs et auxiliaires du ième élément multiplicateur de façon que les trous multiplicateurs et auxiliaires homologues des N éléments multiplicateurs constituent des canaux décrivant une hélice.In order to avoid the return of ions and light to the photocathode through said straight channels, when the device according to the invention is incorporated in a photomultiplier tube, it is envisaged that the multiplier and auxiliary holes of the (i + 1 ) th multiplier element are offset from the multiplier and auxiliary holes of the th multiplier element so that the homologous multiplier and auxiliary holes of the N multiplier elements constitute channels describing a helix.

Le dispositif multiplicateur d'électrons selon l'invention peut être utilisé de façon particulièrement avantageuse à un tube photomultiplicateur comportant une photocathode et au moins une anode. Dans cette utilisation, ledit dispositif multiplicateur est placé entre la photocathode et l'anode, et remplace au moins partiellement les dynodes classiques. Ce type de tube photomultiplicateur présente de multiples avantages: grande surface de collection, bonne linéarité, rapidité et faible encombrement.The electron multiplier device according to the invention can be used in a particularly advantageous manner in a photomultiplier tube comprising a photocathode and at least one anode. In this use, said multiplier device is placed between the photocathode and the anode, and at least partially replaces the conventional dynodes. This type of photomultiplier tube has many advantages: large collection surface, good linearity, speed and small footprint.

Un tube photomultiplicateur particulier comportant une pluralité d'anodes coplanaires adjacentes est remarquable en ce que ledit dispositif multiplicateur est divisé en une pluralité de dispositifs multiplicateurs secondaires séparés par des cloisons étanches aux électrons et perpendiculaires aux plans du dispositif multiplicateur, le dispositif multiplicateur étant placé, d'une part, à proximité de la photocathode de manière telle que les photoélectrons émis par la portion de photocathode située en regard du jème dispositif multiplicateur secondaire ne parviennent pas au (j+1)ème dispositif secondaire, et, d'autre part, parallèlement aux anodes et de manière telle que les cloisons étanches sont situées en regard des zones de séparation de deux anodes consécutives, de façon à réaliser n tubes photomultiplicateurs secondaires dans le même tube photomultiplicateur.A particular photomultiplier tube comprising a plurality of adjacent coplanar anodes is remarkable in that said multiplier device is divided into a plurality of secondary multiplier devices separated by electron-tight partitions and perpendicular to the planes of the multiplier device, the multiplier device being placed, on the one hand, close to the photocathode so that the photoelectrons emitted by the photocathode portion located opposite the jth secondary multiplier device do not reach the (j + 1 ) th secondary device, and, on the other hand, in parallel at the anodes and in such a way that the watertight partitions are located opposite the separation zones of two consecutive anodes, so as to produce n secondary photomultiplier tubes in the same photomultiplier tube.

Ainsi, chaque photomultiplicateur secondaire fournit en sortie un signal électrique proportionnel à l'information lumineuse reçue par l'élément de photocathode correspondant. Ce genre du tube est bien adapté à la localisation de particules nucléaires, par exemple.Thus, each secondary photomultiplier supplies an electrical signal proportional to the light information received by the corresponding photocathode element. This kind of tube is well suited for the localization of nuclear particles, for example.

La description qui va suivre en regard des dessins annexés, donnés à titre d'exemples non limitatifs, fera bien comprendre en quoi consiste l'invention et comment elle peut être réalisée.

  • La fig. 1 est une vue en coupe d'un mode de réalisation de l'élément multiplicateur d'un dispositif multiplicateur d'électrons selon l'invention.
  • La fig. 2 est une vue de dessus de la première plaque de l'élément multiplicateur de la figure 1.
  • La fig. 3 est une vue de dessus d'une première variante d'une première plaque de l'élément multiplicateur d'un dispositif multiplicateur d'électrons selon l'invention.
  • La fig. 4 est une vue de dessus d'une deuxième variante d'une première plaque de l'élément multiplicateur d'un dispositif multiplicateur d'électrons selon l'invention.
  • La fig. 5 est une vue de dessus d'une troisième variante d'une première plaque de l'élément multiplicateur d'un dispositif multiplicateur d'électrons selon l'invention.
  • La fig. 6 est une coupe selon la ligne III-III de la figure 5.
  • La fig. 7 est une coupe d'un dispositif multiplicateur selon l'invention constitué par des éléments multiplicateurs analogues à celui de la figure 1.
  • La fig. 8 est une coupe d'une variante d'exécution du dispositif multiplicateur de la figure 7.
  • La fig. 9 est une coupe d'un dispositif multiplicateur selon l'invention constitué par des éléments multiplicateurs analogues à celui de la figure 6.
  • La fig. 10 est une coupe d'une variante du dispositif multiplicateur de la figure 9.
  • La fig. 11 a est un schéma donnant le principe de réalisation d'un dispositif multiplicateur selon l'invention dont les éléments multiplicateurs sont assemblés en hélice.
  • La fig. 11 b montre un élément multiplicateur se présentant sous une forme propre à la mise en ceuvre du principe de réalisation illustré à la figure 11 a.
  • La fig. 12 est une coupe d'un tube photomultiplicateur comportant un dispositif multiplicateur selon l'invention.
  • La fig. 13 est une coupe d'un tube photomultiplicateur constitué par des photomultiplicateurs secondaires réalisés à l'aide d'un dispositif multiplicateur selon l'invention.
The description which follows with reference to the appended drawings, given by way of nonlimiting examples, will make it clear what the invention consists of and how it can be implemented.
  • Fig. 1 is a sectional view of an embodiment of the multiplier element of an electron multiplier device according to the invention.
  • Fig. 2 is a top view of the first plate of the multiplier element of FIG. 1.
  • Fig. 3 is a top view of a first variant of a first plate of the multiplier element of an electron multiplier device according to the invention.
  • Fig. 4 is a top view of a second variant of a first plate of the multiplier element of an electron multiplier device according to the invention.
  • Fig. 5 is a top view of a third variant of a first plate of the multiplier element of an electron multiplier device according to the invention.
  • Fig. 6 is a section along line III-III of FIG. 5.
  • Fig. 7 is a section through a multiplier device according to the invention constituted by multiplier elements similar to that of FIG. 1.
  • Fig. 8 is a section through an alternative embodiment of the multiplier device of FIG. 7.
  • Fig. 9 is a section through a multiplier device according to the invention constituted by multiplier elements similar to that of FIG. 6.
  • Fig. 10 is a section through a variant of the multiplier device of FIG. 9.
  • Fig. 11 a is a diagram giving the principle of embodiment of a multiplier device according to the invention whose multiplier elements are assembled in a helix.
  • Fig. 11 b shows a multiplier element in a form suitable for the implementation work of the principle of realization illustrated in figure 11 a.
  • Fig. 12 is a section through a photomultiplier tube comprising a multiplier device according to the invention.
  • Fig. 13 is a section through a photomultiplier tube constituted by secondary photomultipliers produced using a multiplier device according to the invention.

La figure 1 montre, en coupe, un élément multiplicateur 11 d'électrons à émission secondaire du type «plaque à trous». Comme le montre la figure 1, cet élément multiplicateur est composé, d'une part, d'une première plaque 12 percée de trous 13, dits trous multiplicateurs, disposés selon un réseau plan régulier. Chaque trou multiplicateur 13 définit, sur une première face 14 de ladite première plaque, une ouverture 15, dite ouverture d'entrée, plus grande que l'ouverture 16, dite ouverture de sortie, définie sur la deuxième face 17 de la première plaque 12, l'ouverture 15 d'entrée de chaque trou multiplicateur étant sensiblement tangente aux ouvertures d'entrée des plus proches voisins dudit trou multiplicateur. D'autre part, l'élément multiplicateur 11 comporte une deuxième plaque 22 parallèle à la première plaque 12, également percée de trous 23, dits trous auxiliaires, dont l'ouverture 25 sur une première face 24 de la deuxième plaque 22, située en regard de la deuxième face 17 de la première plaque 12, est sensiblement égale à l'ouverture 16 de sortie des trous multiplicateurs 13 et plus petite que l'ouverture 26 desdits trous auxiliaires 23 définie sur la deuxième face 27 de la deuxième plaque 22. Comme on peut le voir à la figure 1, lesdites première 12 et deuxième 22 plaques sont isolées électriquement l'une de l'autre, la deuxième plaque 22 étant portée à un potentiel V1 supérieur au potentiel VO de la première plaque 12.FIG. 1 shows, in section, an electron multiplier element 11 with secondary emission of the “hole plate” type. As shown in FIG. 1, this multiplier element is composed, on the one hand, of a first plate 12 pierced with holes 13, called multiplier holes, arranged in a regular plane network. Each multiplier hole 13 defines, on a first face 14 of said first plate, an opening 15, called the inlet opening, larger than the opening 16, called the outlet opening, defined on the second face 17 of the first plate 12 , the inlet opening of each multiplier hole being substantially tangent to the inlet openings of the nearest neighbors of said multiplier hole. On the other hand, the multiplier element 11 comprises a second plate 22 parallel to the first plate 12, also pierced with holes 23, called auxiliary holes, the opening 25 of which on a first face 24 of the second plate 22, located in look of the second face 17 of the first plate 12, is substantially equal to the opening 16 of the outlet of the multiplier holes 13 and smaller than the opening 26 of said auxiliary holes 23 defined on the second face 27 of the second plate 22. As can be seen in FIG. 1, said first 12 and second 22 plates are electrically isolated from each other, the second plate 22 being brought to a potential V1 greater than the potential VO of the first plate 12.

Au moins la première plaque 12 est réalisée dans un matériau pouvant donner lieu à émission secondaire comme un alliage cuivre-béryllium ayant subi le traitement classique: chauffage-migration du béryllium et oxydation. Elle peut être également réalisée dans un matériau peu coûteux, comme l'acier doux, recouvert de matériau à émission secondaire: couche d'alliage cuivre-béryllium oxydée ou couche d'oxyde de manganèse. Par rapport aux multiplicateurs d'électrons, du type «plaque à trous» connus, l'élément multiplicateur 11 selon l'invention offre aux électrons incidents 60 du côté de la première face 14 de la première plaque 12 une surface de collection et de multiplication sensiblement plus grande.At least the first plate 12 is made of a material which can give rise to secondary emission such as a copper-beryllium alloy having undergone the conventional treatment: heating-migration of beryllium and oxidation. It can also be produced in an inexpensive material, such as mild steel, covered with secondary emission material: layer of oxidized copper-beryllium alloy or layer of manganese oxide. Compared to known electron multipliers, of the known “hole plate” type, the multiplier element 11 according to the invention offers incident electrons 60 on the side of the first face 14 of the first plate 12 a collection and multiplication surface. significantly larger.

L'isolation électrique des deux plaques 12 et 22 peut se faire, par exemple, à l'aide de petites billes 70 de verre, de 100 à 200 pm de diamètre scellées à la périphérie desdites plaques. La deuxième plaque 22, dont le potentiel est supérieur à celui de la première plaque 12, joue le rôle d'électrode accélératrice.The electrical insulation of the two plates 12 and 22 can be done, for example, using small glass balls 70, 100 to 200 μm in diameter sealed at the periphery of said plates. The second plate 22, whose potential is greater than that of the first plate 12, acts as an accelerating electrode.

La fig. 2 montre en vue de dessus la première plaque 12 de l'élément multiplicateur 11 de la figure 1. Conformément de la figure 2, les ouvertures d'entrée 15 et de sortie 16 des trous multiplicateurs 13 sont circulaires et ledit réseau plan régulier est carré. La figure 3 donne une première variante de la plaque montrée à la figure 2 qui permet d'augmenter la surface utile de multiplication de la première plaque. Selon la figure 3, les ouvertures d'entrée 15 et de sortie 16 des trous multiplicateurs 13 de la première plaque 12 sont circulaires et ledit réseau plan régulier est hexagonal.Fig. 2 shows a top view of the first plate 12 of the multiplier element 11 in FIG. 1. In accordance with FIG. 2, the inlet 15 and outlet 16 openings of the multiplier holes 13 are circular and said regular flat network is square . FIG. 3 gives a first variant of the plate shown in FIG. 2 which makes it possible to increase the useful multiplication surface of the first plate. According to FIG. 3, the inlet 15 and outlet 16 openings of the multiplier holes 13 of the first plate 12 are circular and said regular plane network is hexagonal.

Si l'on désire augmenter encore l'efficacité de collection et de multiplication de la première plaque, on peut se référer aux figures 4 et 5 dans lesquelles l'ouverture d'entrée 15 des trous multiplicateurs 13 de la première plaque 12 est sensiblement carrée, respectivement hexagonale, et ledit réseau plan régulier est carré, respectivement hexagonal.If one wishes to further increase the collection and multiplication efficiency of the first plate, one can refer to FIGS. 4 and 5 in which the inlet opening 15 of the multiplier holes 13 of the first plate 12 is substantially square , respectively hexagonal, and said regular plane network is square, respectively hexagonal.

Les fig. 5 et 6 montrent une troisième variante d'un élément multiplicateur selon l'invention dans laquelle les ouvertures de sortie 16 des trous multiplicateurs 13 de la première plaque 12 sont décalées par rapport à leurs ouvertures d'entrée 15 de sorte que lesdits trous multiplicateurs 13 sont dissymétriques. La réalisation de tels éléments multiplicateurs se fait par attaque chimique sur les deux faces d'une plaque métallique à travers des masques décalées de façon appropriée.Figs. 5 and 6 show a third variant of a multiplier element according to the invention in which the outlet openings 16 of the multiplier holes 13 of the first plate 12 are offset with respect to their inlet openings 15 so that said multiplier holes 13 are asymmetrical. The realization of such multiplier elements is done by chemical attack on both sides of a metal plate through masks offset appropriately.

La fig. 7 montre en coupe un dispositif multiplicateur d'électrons comportant un empilement parallèle de N (ici N=3) éléments multiplicateurs analogues à celui représenté à la figure 1. Comme on peut l'observer à la figure 7, la distance D entre la deuxième face 27 de la deuxième plaque 22 du ième élément multiplicateur et la première face 14 de la première plaque 12 du (i+ 1)éme élément multiplicateur est plus grande que la distance d séparant les première 12 et deuxième 22 plaques d'un même élément multiplicateur. D'autre part, la deuxième plaque 22 du ième élément multiplicateur est à un potentiel électrique V1 i identique au potentiel électrique VO(i+1) de la première plaque 12 du (i+ 1)éme élément multiplicateur. Le dispositif multiplicateur selon l'invention possède une meilleure efficacité de collection que dans les dispositifs connus, du fait de la bonne efficacité de collection de chaque élément multiplicateur et également de l'effet de distance entre deux éléments multiplicateurs consécutifs.Fig. 7 shows in section an electron multiplier device comprising a parallel stack of N (here N = 3) multiplier elements similar to that represented in FIG. 1. As can be observed in FIG. 7, the distance D between the second side 27 of the second plate 22 of the ith multiplier element and the first face 14 of the first plate 12 of the (i + 1) th multiplier element is greater than the distance d separating the first 12 and second 22 plates of the same multiplier element . On the other hand, the second plate 22 of the ith multiplier element is at an electric potential V1 i identical to the electric potential VO (i + 1) of the first plate 12 of the (i + 1) th multiplier element. The multiplier device according to the invention has better collection efficiency than in the known devices, due to the good collection efficiency of each multiplier element and also the effect of distance between two consecutive multiplier elements.

Les éléments multiplicateurs sont maintenus à la distance D les uns des autres par des entretoises 29 disposées à la périphérie des plaques.The multiplier elements are kept at distance D from each other by spacers 29 arranged at the periphery of the plates.

Dans le mode de réalisation montré à la figure 7, les trous multiplicateurs 13 et auxiliaires 23 du (i+1)ème élément multiplicateur sont situés en regard des trous multiplicateurs et auxiliaires du ième élément multiplicateur, de façon que les trous multiplicateurs et auxiliaires homologues des N éléments multiplicateurs constituent des canaux rectilignes dont la direction 30 est perpendiculaire aux faces des N éléments multiplicateurs. Ce mode de réalisation du dispositif multiplicateur selon l'invention offre l'avantage de pouvoir être utilisé dans un tube du type intensifi- cateur d'images puisque les électrons secondaires sortant d'un canal du dispositif sont issus de la multiplication des électrons incidents 60 pénétrant dans le même canal.In the embodiment shown in FIG. 7, the multiplier 13 and auxiliary holes 23 of the (i + 1) th multiplier element are located opposite the multiplier and auxiliary holes of the i th multiplier element, so that the homologous multiplier and auxiliary holes N multiplying elements constitute rectilinear channels whose direction 30 is perpendicular to the faces of the N multiplying elements. This embodiment of the multiplier device according to the invention offers the advantage of being able to be used in a tube of the image intensifier type since the secondary electrons leaving a channel of the device result from the multiplication of incident electrons 60 entering the same channel.

La fig. 8 représente en coupe une variante d'exécution du dispositif multiplicateur de la figure 7, variante dans laquelle les trous multiplicateurs 13 et auxiliaires 23 du (i+1 )ème élément multiplicateur sont décalés par rapport aux trous multiplicateurs et auxiliaires du ième élément multiplicateur de façon que les trous multiplicateurs et auxiliaires homologues des N éléments multiplicateurs constituent des canaux rectilignes dont la direction 31 fait un angle aigu avec la normale 30 aux faces des N éléments multiplicateurs. Cette variante d'exécution permet d'augmenter le gain du dispositif multiplicateur selon l'invention puisque des électrons incidents qui traverseraient un élément multiplicateur au cente d'un trou multiplicateur, donc sans multiplication, sont alors multipliés par l'élément multiplicateur suivant alors qu'ils ne le seraient pas dans le mode de réalisation de la figure 7. Par contre, comme le montre la figure 8, le dispositif représenté ne peut pas être utilisé pour la formation d'images car il n'y a pas correspondance univoque entre un trou multiplicateur donné du 1ème élément multiplicateur et un trou multiplicateur de Nième et dernier élément multiplicateur.Fig. 8 shows in section an alternative embodiment of the multiplier device of FIG. 7, variant in which the multiplier 13 and auxiliary holes 23 of the (i + 1) th multiplier element are offset with respect to the multiplier and auxiliary holes of the ith multiplier element so that the homologous multiplier and auxiliary holes of the N multiplier elements constitute rectilinear channels whose direction 31 makes an acute angle with the normal 30 to the faces of the N multiplier elements. This variant of execution makes it possible to increase the gain of the multiplier device according to the invention since incident electrons which would pass through a multiplier element at the center of a multiplier hole, therefore without multiplication, are then multiplied by the following multiplier element whereas 'they would not be in the embodiment of Figure 7. By cons, as shown in Figure 8, the device shown can not be used for image formation because there is no one-to-one correspondence between a given multiplier hole of the 1st multiplier element and a multiplier hole of Nth and last multiplier element.

On peut cependant obtenir à la fois un bon rendement électronique et la possibilité de formation d'images en utilisant des éléments multiplicateurs à trous multiplicateurs dissymétriques tels que représentés à la figure 6. C'est le cas du dispositif multiplicateur montré à la figure 9. Afin d'éviter le décalage entre l'image d'entrée et l'image de sortie, décalage qui peut ête important si le nombre N d'éléments multiplicateurs est grand, il est prévu, comme le montre la figure 10, que les trous multiplicateurs dissymétriques 13 du (i+1)ème élément multiplicateur sont en configuration tête-bêche par rapport aux trous multiplicateurs dissymétriques du ième élément multiplicateur.However, both good electronic efficiency and the possibility of image formation can be obtained by using multiplier elements with asymmetric multiplier holes as shown in FIG. 6. This is the case of the multiplier device shown in FIG. 9. In order to avoid the offset between the input image and the output image, which offset can be significant if the number N of multiplying elements is large, it is provided, as shown in FIG. 10, that the holes asymmetric multipliers 13 of the (i + 1) th multiplier element are in head-to-tail configuration with respect to the asymmetric multiplier holes of the i th multiplier element.

Afin d'éviter que des ions ou de la lumière ne remontent vers la photocathode par lesdits canaux rectilignes dans le cas où le dispositif selon l'invention fait partie d'un tube photomultiplicateur, on prévoit, en référence à la figure 11 a, que les trous multiplicateurs 13 et auxiliaires 23 du (i+1 )ème élément multiplicateur sont décalés par rapport aux trous multiplicateurs et auxiliaires du ième élément multiplicateur de façon que le trous multiplicateurs et auxiliaires homologues des N éléments multiplicateurs constituent des canaux décrivant une hélice.In order to prevent ions or light from going up towards the photocathode by said rectilinear channels in the case where the device according to the invention forms part of a photomultiplier tube, provision is made, with reference to FIG. 11 a, that the multiplier 13 and auxiliary holes 23 of the (i + 1) th multiplier element are offset with respect to the multiplier and auxiliary holes of the ith multiplier element so that the homologous multiplier and auxiliary holes of the N multiplier elements constitute channels describing a helix.

Les axes (x, y) des N éléments multiplicateurs restent parallèles entre eux, mais les centres 70 des trous auxiliaires 23 de référence sont régulièrement répartis sur un cercle donné 71. Les centres 70 de deux trous 23 consécutifs font avec le centre 72 du cercle 71 un angle donné a qui dépend du nombre total N d'éléments multiplicateurs. La figure 11 b montre en vue de dessus une plaque d'un élément multiplicateur en forme de triangle et dont la partie utile est représentée par le cercle 80. Cette plaque possède une patte 81 de connexion électrique et est percée de trois trous 82 qui permettent l'assemblage des plaques des éléments multiplicateurs à l'aide de colonnettes passant par les trous 82. Le décalage en hélice est obtenu en décalant en sens contraire la position des trois trous 82 après avoir déterminé les origines des axes (x, y) par des pions de fixation qui pénètrent dans des trous multiplicateurs ou auxiliaires de la zone centrale 80.The axes (x, y) of the N multiplying elements remain parallel to each other, but the centers 70 of the auxiliary reference holes 23 are regularly distributed over a given circle 71. The centers 70 of two consecutive holes 23 make with the center 72 of the circle 71 a given angle a which depends on the total number N of multiplying elements. FIG. 11 b shows a top view of a plate of a triangle-shaped multiplier element, the useful part of which is represented by the circle 80. This plate has a tab 81 for electrical connection and is pierced with three holes 82 which allow assembling the plates of the multiplying elements using posts passing through the holes 82. The helical offset is obtained by shifting the position of the three holes 82 in opposite directions after having determined the origins of the axes (x, y) by fixing pins which penetrate into multiplier or auxiliary holes in the central area 80.

Le dispositif multiplicateur d'électrons selon l'invention trouve une application particulièrement avantageuse aux tubes photomultiplicateurs. Comme le montre la figure 12, le tube photomultiplicateur comporte une photocathode 41 et une anode 42; le dispositif multiplicateur 40 selon l'invention est placé entre la photocathode 41 et l'anode 42, l'ouverture d'entrée 15 des trous multiplicateurs étant orientée vers la photocathode 41. Dans l'exemple de la figure 12, le tube possède une première dynode 43 qui peut être de grande dimension, d'où une plus grande efficacité de collection ainsi qu'une meilleure linéarité, une meilleure rapidité et un encombrement plus faible.The electron multiplier device according to the invention finds a particularly advantageous application to photomultiplier tubes. As shown in FIG. 12, the photomultiplier tube comprises a photocathode 41 and an anode 42; the multiplier device 40 according to the invention is placed between the photocathode 41 and the anode 42, the inlet opening 15 of the multiplier holes being oriented towards the photocathode 41. In the example of FIG. 12, the tube has a first dynode 43 which can be of large size, hence greater collection efficiency as well as better linearity, better speed and less bulk.

La figure 13 montre, en coupe, une autre application de l'invention à un tube photomultiplicateur comportant n anodes 42 adjacentes. Dans cette application, ledit dispositif multiplicateur est divisé en une pluralité n de dispositifs multiplicateurs secondaires séparés par des cloisons 50 étanches aux électrons et perpendiculaires aux plans du dispositif multiplicateur, le dispositif multiplicateur étant placé, d'une part, à proximité de la photocathode de manière telle que les photoélectrons émis par la position de photocathode située en regard du jème dispositif multiplicateur secondaire ne parviennent pas au (j:!:1)ème dispositif secondaire, et, d'aute part, parallèlement aux anodes 42 et de manière telle que les cloisons 50 étanches sont situées en regard des zones 51 de séparation de deux anodes 42 consécutives, de façon à réaliser n tubes photomultiplicateurs secondaires dans le même tube photomultiplicateur. Les tubes du type de celui représenté à la figure 13 trouvent une utilisation avantageuse en physique nucléaire car ils permettent une localisation précise des particules détectées. Les cloisons étanches 50 peuvent être réalisées de façon classique par masquage et photogravure d'une plaque métallique.FIG. 13 shows, in section, another application of the invention to a photomultiplier tube comprising n adjacent anodes 42. In this application, said multiplier device is divided into a plurality n of secondary multiplier devices separated by partitions 50 that are electron-tight and perpendicular to the planes of the multiplier device, the multiplier device being placed, on the one hand, near the photocathode of in such a way that the photoelectrons emitted by the photocathode position situated opposite the jth secondary multiplier device do not reach the (j:!: 1) th secondary device, and, on the other hand, parallel to the anodes 42 and in such a way that the watertight partitions 50 are located opposite the zones 51 of separation of two consecutive anodes 42, so as to produce n secondary photomultiplier tubes in the same photomultiplier tube. Tubes of the type shown in FIG. 13 find advantageous use in nuclear physics because they allow precise localization of the particles detected. The watertight partitions 50 can be produced in a conventional manner by masking and photoengraving of a metal plate.

Claims (8)

1. An electron multiplier device comprising a parallel stack of N multiplier elements (11) of secondary emission of the «apertured plate» type each of which comprises a plate (12) having multiplier holes (13) arranged in a regular plane pattern, each multiplier hole (13) defining, on a first surface (14) of the said plate (12) an input aperture (15) and, on the second surface (17) of the plate (12), an output aperture (16) which is smaller than the input aperture (15), characterized in that each multiplier element comprises a second plate (22), which is parallel to the above-mentioned first plate (12), which also comprises auxiliary holes (23) the aperture (25) of which is on a first surface (24) of the second plate (22) which is situated opposite to the second surface (17) of the first plate (12) is substantially equal to the output aperture (16) of the multiplier holes (13) and is smaller than the aperture (26) of the said auxiliary holes (23) which is defined on the second surface (27) of the second plate (22), in that
the input aperture (15) of each multiplier hole (13) is substantially tangent to the input apertures of the nearest neighbours of the said multiplier hole, in that
the first (12) and second (22) plates of each multiplier element (11) are electrically insulated from each other, in that
the spacing (D) between the second surface (27) of the second plate (22) of the i-th multiplier element and the first surface (14) of the first plate (12) of the (i+1 )th multiplier element is larger than the spacing (d) which separates the first (12) and the second (22) plates of the same multiplier element (11), and in that

whilst i (i) designates the row occupied by a multiplier element (11) in the stacking as from the input surface of primary electrons, the device comprises means for all the values of i (i) to bring the second plate (22) of the i-th multiplier element to an electric potential Vli (Vii) which is higher than the potential VOi (VOi) of the first plate (12) of the said i-th multiplier element, which potential Vli (Vii), for the values of i (i) not exceeding N-1 (N-1), is identical to the electric potential V0(i+1) (V0(i+1)) of the first plate (12) of the (i+1 )th multiplier element.
2. An electron multiplier device as claimed in Claim 1, characterized in that the multiplier holes (13) and auxiliary holes (23) of the (i+1)th multiplier element are situated with respect to the multiplier holes and auxiliary holes of the ith multiplier element in such manner that the corresponding multiplier holes and auxiliary holes of the N multiplier elements constitute rectilinear channels the direction (30) of which is at right angles to the surfaces of the N multiplier elements.
3. An electron multiplier device as claimed in Claim 1, characterized in that the multiplier holes (13) and auxiliary holes (23) of the (i+1)th multiplier element are shifted with respect to the multiplier holes and auxiliary holes of the ith multiplier element in such manner that the corresponding multiplier holes and auxiliary holes of the N multiplier elements constitute rectilinear channels the direction (31) of which encloses an acute angle with the normal (30) to the surfaces of the N multiplier elements.
4. An electron multiplier device as claimed in Claim 3, characterized in that the output apertures (16) of the multiplier holes (13) of the first plate (12) are shifted with respect to their input apertures (15) in such manner that the said multiplier holes (13) are asymmetrical.
5. An electron multiplier device as claimed in Claim 4, characterized in that the asymmetric multiplier holes (13) of the (i+1)th multiplier element are in a head-tail configuration with respect to the asymmetrical multiplier holes of the ith multiplier element.
6. An electron multiplier device as claimed in Claim 1, characterized in that the multiplier holes (13) and the auxiliary holes (23) of the (i+1)th multiplier element are shifted with respect to the multiplier and auxiliary holes and the ith multiplier element in such manner that the corresponding multiplier holes and auxiliary holes of the N multiplier elements constitute channels which describe a helix.
7. A photomultiplier tube having a photocathode (41) at least an anode (42) and an electron multiplier device as claimed in any of Claims 1 to 6, characterized in that the multiplier device is placed between the photocathode (41) and the anode (42), the input aperture (15) of the multiplier holes (13) being directed towards the photocathode (41).
8. A photomultiplier tube as claimed in Claim 7, comprising a plurality of co-planer.(n) adjoining anodes (42), characterized in that the said multiplier device is devided into a plurality of n (n) secondary multiplier devices separated by partitions 50 (50) which are closed for the electrons and which are perpendicular to the planes of the multiplier device, the multiplier device being placed in the proximity of the photocathode in such manner that the photoelectrons emitted by the portion of the photocathode situated opposite to the j-th secondary multiplier device do not reach the (j±1)th secondary device, and being parallel to the anodes 42 (42) in such manner that the imprevious partitions 50 (50) are situated opposite to the separation zones 51 (51) of the two successive anodes 42 (42) in such manner that n secondary photomultiplier tubes are realised in the same photomultiplier tube.
EP84200994A 1983-07-11 1984-07-10 Electron multiplier element, electron multiplying device made up of this element and its application to a photomultiplier tube Expired EP0131339B1 (en)

Applications Claiming Priority (2)

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FR8311514 1983-07-11
FR8311514A FR2549288B1 (en) 1983-07-11 1983-07-11 ELECTRON MULTIPLIER ELEMENT, ELECTRON MULTIPLIER DEVICE COMPRISING THE MULTIPLIER ELEMENT AND APPLICATION TO A PHOTOMULTIPLIER TUBE

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EP0131339A1 EP0131339A1 (en) 1985-01-16
EP0131339B1 true EP0131339B1 (en) 1988-06-01

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FR2592523A1 (en) * 1985-12-31 1987-07-03 Hyperelec Sa HIGH EFFICIENCY COLLECTION MULTIPLIER ELEMENT
DE3609967A1 (en) * 1986-03-25 1987-10-01 Standard Elektrik Lorenz Ag CONTROL DISC FOR IMAGE DISPLAY DEVICES
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JPS6039752A (en) 1985-03-01
JPH056301B2 (en) 1993-01-26
FR2549288A1 (en) 1985-01-18
FR2549288B1 (en) 1985-10-25
CA1223029A (en) 1987-06-16
EP0131339A1 (en) 1985-01-16
DE3471820D1 (en) 1988-07-07
US4649314A (en) 1987-03-10

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