EP0033894B1 - Plural-stage vacuum x-ray image amplifier - Google Patents

Plural-stage vacuum x-ray image amplifier Download PDF

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Publication number
EP0033894B1
EP0033894B1 EP81100574A EP81100574A EP0033894B1 EP 0033894 B1 EP0033894 B1 EP 0033894B1 EP 81100574 A EP81100574 A EP 81100574A EP 81100574 A EP81100574 A EP 81100574A EP 0033894 B1 EP0033894 B1 EP 0033894B1
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Prior art keywords
screen
layer
carrier
photo
image
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EP81100574A
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German (de)
French (fr)
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EP0033894A1 (en
Inventor
Ulrich Kröner
Walter Dipl.-Phys. Greschat
Peter Römer
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Siemens AG
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Siemens AG
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/50—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output
    • H01J31/508—Multistage converters

Definitions

  • the invention relates to multi-stage X-ray image intensifiers (RBV) according to the preamble of claim 1.
  • RBV X-ray image intensifiers
  • the individual stages which amplify the electron image by acceleration in the electric field, are coupled to one another via screens, the essential elements of which are a luminescent layer and an optical one with it Have contact standing photocathode layer.
  • these two reactive layers usually have little strength in themselves. They are therefore attached to both sides of a sufficiently stable carrier plate, which allows the light released in the luminescent layer to pass through to the photocathode layer provided on the other side.
  • the carrier must be designed in such a way that a good «contact copy» of the fluorescent screen image is created on the photocathode, i.e. that the carrier does not reduce the sharpness of the image. This is e.g. achievable through the use of fiber optic plates as supports for the layers. However, they have the major disadvantage that they are very expensive.
  • the thickness of the carrier layer must not cause any significant scattering of the light passing through.
  • the image sharpness that can usually be used in RBV, e.g. up to 50 ⁇ m still allowed.
  • the phosphor layer is first applied to the carrier. This is followed by installation in the image intensifier arrangement and finally the photocathode layer is applied to the still free surface of the support opposite the luminous layer.
  • a gamma camera which has an image intensifier part, the input screen of which is constructed on a 1 to 2 mm thick single crystal fluorescent screen.
  • a barrier layer made of, for example, cesium iodide, cesium iodide sodium, bismuth germanate or aluminum oxide is vapor-deposited between the screen and the photocathode layer in order to prevent the effect of impurities on the crystal. If a second stage is also provided, this is built up on a fiber optic plate, which serves as a carrier for a luminescent layer and a further photocathode layer.
  • the method used for their formation must be adapted to the substrate in question.
  • a special source of antimony is required for each substrate.
  • the invention is based on the object, in image intensifiers according to the preamble of claim 1, to counteract the effects of an unavoidable soiling of the support of the photocathode of a coupling screen, so that local faults in the photocathode are avoided, all photocathodes of the image intensifier in a single manufacturing process by means of a single one Source can be produced and a uniform formation of the photo cathodes of the image intensifier stages is nevertheless obtained.
  • This object is achieved according to the invention by the measures specified in the characterizing part of claim 1.
  • the subjects of the subclaims relate to advantageous developments of the invention.
  • the invention is based on the fact that a clean base for the photocathodes can be obtained by applying a clean covering before the photocathodes are applied.
  • it has proven to be expedient to provide surfaces on the entrance screen as well as on the intermediate screen which are of the same type and at the same time form a barrier against influences from the base.
  • care must be taken to ensure that the application on the coupling screen is thin in order to keep the loss of light and sharpness low, i.e. so that the light passing from the screen into the photocathode is not unduly absorbed and scattered.
  • An antimony (Sb1 source) can be used in the invention, whereas in the known production a special Sb source was required for each photocathode because of the necessary adaptation to the substrate. If water-soluble cesium iodide is used as the material of the additional layer, this can be done Cathode material can be simply rinsed off with water together with the background vaporization.
  • the technology according to the invention can also be used with advantage where subsequent cleaning of the base of the photocathode itself would be possible.
  • the intermediate layer can generally achieve a significant simplification in addition to the advantages stated above, because the cleaning step can be dispensed with (cleaning, polishing, etc.).
  • 1 denotes a vacuum-tight bulb, which carries on its one end wall 2 in the interior of the bulb a luminous layer 3 that is sensitive to X-ray light, which can consist, for example, of sodium-doped cesium iodide (CsJ: Na) and which is followed by a photocathode layer 4 .
  • CsJ cesium iodide
  • a photocathode layer 4 At a distance of approx. 12 mm follows an electron-sensitive fluorescent screen, which consists of an electron-transmissive, light-reflecting cover 5 made of aluminum and a fluorescent layer 6. This rests on a support 7, which consists of mica and is 50 / km thick.
  • the carrier 7 On its free surface, the carrier 7 is provided with a coating 8 made of cesium iodide, which is 8 microns thick.
  • a photocathode layer 9 which corresponds to layer 4 is applied to layer 8.
  • a voltage of 15 kV is applied between the photocathode 4 and the aluminum layer 5 for close focusing and acceleration from a direct current source 13.
  • a voltage of 20 kV from a source 14 is applied between the photocathode layer 9 and the aluminum cover 11.
  • a beam of rays 17 coming from an X-ray tube 16 is directed onto a body 18 from a device 15 for generating X-rays.
  • the rays from the bundle 17 come through the input window 2 onto the fluorescent screen 3, where they generate light which acts on the photocathode 4 and triggers electrons there. These are then accelerated according to the indication by dotted lines 19 on the fluorescent screen consisting of 5 and 6.
  • the electrons trigger light again in the sense of the desired imaging and amplification 19, which acts on the photocathode 9 through the support 7 and the coating 8 and there again triggers an electron beam 20, which then emits light in the phosphor screen consisting of 11 and 12 triggers, which, as indicated by arrows 21, can be observed from the outside.

Description

Die Erfindung betrifft mehrstufige Röntgenbildverstärker (RBV) nach dem Oberbegriff des Anspruchs 1. Derartige Bildverstärker sind etwa bekannt aus der US-A-2 555 423.The invention relates to multi-stage X-ray image intensifiers (RBV) according to the preamble of claim 1. Such image intensifiers are known, for example, from US Pat. No. 2,555,423.

Bei mehrstufigen Bildverstärkern, bei denen das Röntgenbild zuerst in ein Elektronen-Bild umgewandelt wird, sind die einzelnen, das Elektronen-Bild jeweils durch Beschleunigung im elektrischen Feld verstärkenden Stufen über Schirme miteinander gekoppelt, die als wesentliche Elemente eine Leuchtschicht und eine optisch mit dieser in Kontakt stehende Fotokathodenschicht aufweisen. Diese beiden reaktiven Schichten haben aberfür sich gewöhnlich nur wenig Festigkeit. Sie werden deshalb zu beiden Seiten einer ausreichend stabilen Trägerplatte angebracht, welche das in der Leuchtschicht ausgelöste Licht zu der auf der anderen Seite angebrachten Fotokathodenschicht hindurchlässt.In multi-stage image intensifiers, in which the x-ray image is first converted into an electron image, the individual stages, which amplify the electron image by acceleration in the electric field, are coupled to one another via screens, the essential elements of which are a luminescent layer and an optical one with it Have contact standing photocathode layer. However, these two reactive layers usually have little strength in themselves. They are therefore attached to both sides of a sufficiently stable carrier plate, which allows the light released in the luminescent layer to pass through to the photocathode layer provided on the other side.

Der Träger muss so gestaltet sein, dass eine gute «Kontaktkopie» des Leuchtschirmbildes auf der Fotokathode entsteht, d.h., dass der Träger keine Verringerung der Abbildungsschärfe bewirkt. Dies ist z.B. durch die Verwendung von Faseroptikplatten als Träger für die Schichten erreichbar. Sie haben aber den wesentlichen Nachteil, dass sie sehr teuer sind.The carrier must be designed in such a way that a good «contact copy» of the fluorescent screen image is created on the photocathode, i.e. that the carrier does not reduce the sharpness of the image. This is e.g. achievable through the use of fiber optic plates as supports for the layers. However, they have the major disadvantage that they are very expensive.

Eine Verringerung der Kosten wäre durch die Verwendung durchsichtiger Platten oder Folien, etwas aus Glas, Glimmer bzw. einem vakuumfesten organischen Material (z.B. Polyimid) oder ähnlichem, erreichbar. Dabei darf aber die Dicke der Trägerschicht keine wesentliche Streuung des durchgehenden Lichtes bewirken. Für die in RBV in der Regel brauchbaren Abbildungsschärfen wïen z.B. bis zu 50 um noch zulässig. Auf den Träger wird bei bekannten Verfahren zuerst die Leuchtstoffschicht aufgetragen. Hierauf erfolgt der Einbau in die Bildverstärkeranordnung und schliesslich das Aufbringen der Fotokathodenschicht auf die der Leuchtschicht gegenüberliegende noch freie Fläche des Trägers.A reduction in costs could be achieved by using transparent plates or foils, something made of glass, mica or a vacuum-proof organic material (e.g. polyimide) or the like. However, the thickness of the carrier layer must not cause any significant scattering of the light passing through. For the image sharpness that can usually be used in RBV, e.g. up to 50 µm still allowed. In known methods, the phosphor layer is first applied to the carrier. This is followed by installation in the image intensifier arrangement and finally the photocathode layer is applied to the still free surface of the support opposite the luminous layer.

Die meisten in bekannter Weise hergestellten Zwischenschirme weisen ungleichmässige Helligkeits- übertragung über die Fläche auf. Dies ist etwa dadurch erklärbar, dass selbst eine ursprünglich genügend saubere Fläche bei der Sedimentation des Leuchtstoffs auf die eine Seite des Trägers die gegenüberliegende, später mit der Fotokathode zu belegende Seite durch die bei der Herstellung des Leuchtschirms verwendeten Mittel «verschmutzt» wird, weil wegen der Empfindlichkeit der dünnen Folie kein ausreichender Schutz möglich ist. Auf der geringen Stabilität der Folie beruht es auch, dass die «verschmutzte» Fläche nicht nachträglich ausreichend gereinigt werden kann. So werden die lokalen Störungen der Fotokathode und damit ein fleckiges Bild erhalten.Most intermediate screens manufactured in a known manner have uneven brightness transmission over the surface. This can be explained, for example, by the fact that even a surface that was originally sufficiently clean during sedimentation of the phosphor on one side of the support "dirty" the opposite side, which would later be covered with the photocathode, by the means used in the manufacture of the fluorescent screen, because of the sensitivity of the thin film is insufficient protection. The low stability of the film also means that the “dirty” surface cannot be cleaned sufficiently afterwards. In this way, the local faults in the photocathode and thus a spotty image are obtained.

Aus der GB-A-2 016 206 (insbesondere Seite 4, Zeilen 7 bis 27) ist eine Gammakamera bekannt, die einen Bildverstärkerteil aufweist, dessen Eingangsschirm auf einem 1 bis 2 mm dicken Einkristall-Leuchtschirm aufgebaut ist. Dabei ist zwischen dem Schirm und der Fotokathodenschicht eine Sperrschicht etwa aus Cäsiumjodid, Cäsiumjodid-Natrium, Wismutgermanat oder Aluminiumoxid aufgedampft, um die Wirkung von Unreinheiten am Kristall zu verhindern. Falls noch eine zweite Stufe vorgesehen wird, ist diese auf einer Fiberoptikplatte aufgebaut, die als Träger für eine Leuchtschicht und eine weitere Fotokathodenschicht dient. Um sowohl an der Sperrschicht als auch an der Fiberoptikplatte Fotokathoden gleichartigen Aufbaus zu erzielen, muss das zu ihrer Formierung angewandte Verfahren jeweils vorliegendem Substrat angepasst werden. Etwa bei der Herstellung einer Antimon-Cäsium-Fotokathode ist für jedes Substrat eine spezielle Antimonquelle nötig.From GB-A-2 016 206 (in particular page 4, lines 7 to 27) a gamma camera is known which has an image intensifier part, the input screen of which is constructed on a 1 to 2 mm thick single crystal fluorescent screen. A barrier layer made of, for example, cesium iodide, cesium iodide sodium, bismuth germanate or aluminum oxide is vapor-deposited between the screen and the photocathode layer in order to prevent the effect of impurities on the crystal. If a second stage is also provided, this is built up on a fiber optic plate, which serves as a carrier for a luminescent layer and a further photocathode layer. In order to achieve photocathodes of the same structure both on the barrier layer and on the fiber optic plate, the method used for their formation must be adapted to the substrate in question. For example, when producing an antimony-cesium photocathode, a special source of antimony is required for each substrate.

Der Erfindung liegt die Aufgabe zugrunde, bei Bildverstärkern nach dem Oberbegriff des Anspruchs 1 den Auswirkugen einer unvermeidbaren Verschmutzung des Trägers der Fotokathode eines Kopplungsschirmes wirksame Mittel entgegenzusetzen, so dass lokale Störungen der Fotokathode vermieden werden, alle Fotokathoden des Bildverstärkers in einem einheitlichen Herstellungsprozess mittels einer einzigen Quelle herstellbar sind und trotzdem eine einheitliche Formierung der Fotokathoden der Bildverstärkerstufen erhalten wird. Diese Aufgabe wird erfindungsgemäss durch die im kennzeichnenden Teil des Anspruchs 1 angegebenen Massnahmen gelöst. die Gegenstände der Unteransprüche betreffen vorteilhafte Weiterbildungen der Erfindung.The invention is based on the object, in image intensifiers according to the preamble of claim 1, to counteract the effects of an unavoidable soiling of the support of the photocathode of a coupling screen, so that local faults in the photocathode are avoided, all photocathodes of the image intensifier in a single manufacturing process by means of a single one Source can be produced and a uniform formation of the photo cathodes of the image intensifier stages is nevertheless obtained. This object is achieved according to the invention by the measures specified in the characterizing part of claim 1. the subjects of the subclaims relate to advantageous developments of the invention.

Die Erfindung geht davon aus, dass eine saubere Basis für die Fotokathoden dadurch erhalten werden kann, dass vor der Auftragung der Fotokathoden eine saubere Belegung angebracht wird. Ausserdem hat es sich als zweckmässig erwiesen, sowohl am Eingangsschirm als auch am Zwischenschirm Flächen vorzusehen, die gleichartig sind und gleichzeitig eine Sperre gegenüber Einwirkungen aus der Unterlage bilden. Dabei ist allerdings darauf zu achten, dass die Auftragung auf dem Kopplungsschirm dünn sein soll, um den Verlust an Licht und Schärfe gering zu halten, d.h., damit das vom Leuchtschirm in die Fotokathode übertretende Licht nicht ungebührlich absorbiert und gestreut wird.The invention is based on the fact that a clean base for the photocathodes can be obtained by applying a clean covering before the photocathodes are applied. In addition, it has proven to be expedient to provide surfaces on the entrance screen as well as on the intermediate screen which are of the same type and at the same time form a barrier against influences from the base. However, care must be taken to ensure that the application on the coupling screen is thin in order to keep the loss of light and sharpness low, i.e. so that the light passing from the screen into the photocathode is not unduly absorbed and scattered.

Durch die zusätzliche Schicht ergeben sich folgende Vorteile:

  • a) Kathodenverträgliche Diffusionssperre gegen Verunreinigungen der Trägeroberfläche, die sonst zur partiellen «Vergiftung» der Fotokathode führen können.
  • b) Sowohl auf dem Eingangsschirm als auch auf dem Träger des bzw. der Zwischenschirme wird gleiches Substrat für die Fotokathode erhalten, so dass gleichmässigere Kathoden erzielt werden können.
  • c) Bei fehlerhafter Herstellung der Fotokathode und Verwendung einer zusätzlichen Schicht aus einem Mittel, das in einer Flüssigkeit löslich ist, die den Träger nicht angreift, kann die Fotokathodenschicht zusammen mit der zusätzlichen Schicht abgewaschen und der Schirm erneut verwendet werden.
The additional layer has the following advantages:
  • a) Cathode compatible diffusion barrier against contamination of the carrier surface, which can otherwise lead to partial "poisoning" of the photocathode.
  • b) The same substrate for the photocathode is obtained both on the input screen and on the support of the intermediate screen (s), so that more uniform cathodes can be achieved.
  • c) If the photocathode is manufactured incorrectly and an additional layer of an agent which is soluble in a liquid which does not attack the support is used, the photocathode layer can be washed off together with the additional layer and the screen can be used again.

Bei z.Z. üblichen Röntgenbildverstärkern, bei denen Cäsiumjodid mit Natrium dotiert (CsJ:Na) als Leuchtstoff des Eingangsschirms verwendet wird, hat sich eine Bedampfung des Kopplungsschirmes mit CsJ:Na als günstig erwiesen. Die Dicke der Bedampfung der später mit der Fotokathodenschicht zu belegenden Flächen sollte wenigstens so stark sein, dass eine dichte Abdeckung der Unterlage erhalten wird. Wenn diese erreicht ist, kann die Aufdampfung mit Cäsiumjodid abgebrochen werden. Eine Obergrenze ist durch die noch akzeptierbare Bildunschärfe gegeben.In current X-ray image intensifiers, in which cesium iodide doped with sodium (CsJ: Na) is used as the phosphor of the input screen, vaporization of the coupling screen with CsJ: Na has proven to be advantageous. The thickness of the vapor deposition on the surfaces to be covered later with the photocathode layer should be at least as strong be that a tight cover of the underlay is obtained. When this is reached, the evaporation can be stopped with cesium iodide. An upper limit is given by the still acceptable image blur.

Ein Verfahren, das sich als günstig erwiesen hat, besteht darin, dass die «verschmutzte» Oberfläche vor der Belegung mit der Fotokathode mit einer Schicht aus CsJ:Na belegt wird, die 5 bis 10 t-tm dick ist. So wird eine sehr saubere Unterlage für die Fotokathode erhalten. Ausserdem bekommen sowohl der Eingangsschirm als auch der bzw. die Zwischenschirm(e) Flächen gleichen Materials, d.h. es entsteht gleiches Substrat. Das bewirkt die Möglichkeit, die Fotokathoden in gleichem bzw. ähnlichem Ablauf herzustellen. So können Kathoden gleicher Cäsiumsättigung erhalten werden. Bei früheren Methoden konnte eine Übersättigung einer Kathode wegen an unterschiedlichen Unterlagen auftretenden unterschiedlichen Formierungsgeschwindigkeiten vorkommen. Bei der Erfindung kann man mit einer Antimon-(Sb1-Quelle auskommen, während man bei der bekannten Herstellung für jede Fotokathode wegen der notwendigen Anpassung an das Substrat eine spezielle Sb-Quelle benötigte. Bei Verwendung von wasserlöslichem Cäsiumjodid als Material der zusätzlichen Schicht kann das Kathodenmaterial zusammen mit der Untergrundbedampfung einfach mit Wasser abgespült werden.One method that has proven to be favorable is that the “dirty” surface is covered with a layer of CsJ: Na, which is 5 to 10 t-tm thick, before being coated with the photocathode. In this way, a very clean underlay for the photo cathode is obtained. In addition, both the entrance screen and the intermediate screen (s) are given areas of the same material, i.e. the same substrate is created. This makes it possible to manufacture the photocathodes in the same or a similar process. In this way, cathodes of the same cesium saturation can be obtained. In earlier methods, cathode oversaturation could occur due to different formation rates occurring on different substrates. An antimony (Sb1 source) can be used in the invention, whereas in the known production a special Sb source was required for each photocathode because of the necessary adaptation to the substrate. If water-soluble cesium iodide is used as the material of the additional layer, this can be done Cathode material can be simply rinsed off with water together with the background vaporization.

Die erfindungsgemässe Technik ist auch dort mit Vorteil einzusetzen, wo eine nachträgliche Reinigung der Fotokathodengrundfläche an sich möglich wäre. Durch die Zwischenschicht kann in der Regel neben den oben angegebenen Vorteilen eine wesentliche Vereinfachung erreicht werden, weil sich der Reinigungsschritt erübrigen kann (reinigen, polieren usw.).The technology according to the invention can also be used with advantage where subsequent cleaning of the base of the photocathode itself would be possible. The intermediate layer can generally achieve a significant simplification in addition to the advantages stated above, because the cleaning step can be dispensed with (cleaning, polishing, etc.).

Einzelheiten und Vorteile der Erfindung werden nachfolgend anhand der in der Figur im Querschnitt dargestellten Ausführungsform als Flach-RBV weiter erläutert.Details and advantages of the invention are further explained below using the embodiment shown in cross-section in the figure as a flat RBV.

In der Figur ist mit 1 ein vakuumdichter Kolben bezeichnet, der an seiner einen Endwand 2 im Inneren des Kolbens eine für Röntgenlicht empfindliche Leuchtschicht 3 trägt, die beispielsweise aus mit Natrium dotiertem Cäsiumjodid (CsJ:Na) bestehen kann und auf welche eine Fotokathodenschicht 4 folgt. In einem Abstand von ca. 12 mm folgt ein elektronenempfindlicher Leuchtschirm, der aus einer elektronendurchlässigen, lichtreflektierenden Abdeckung 5 aus Aluminium besteht und einer Leuchtschicht 6. Diese ruht auf einem Träger 7, der aus Glimmer besteht und 50 /km dick ist. An seiner freien Fläche ist der Träger 7 mit einer Belegung 8 aus Cäsiumjodid versehen, die 8 µm stark ist. Schliesslich ist auf die Schicht 8 eine mit der Schicht 4 übereinstimmende Fotokathodenschicht 9 aufgetragen. Die an der der Eingangsseite 2 gegenüberliegenden Ausgangsseite 10 liegende Leuchtschirmkombination besteht, wie diejenige im Zwischenschirm mit 5 und 6 bezeichnete, aus einer Abdeckung 11 aus Aluminium und einer Leuchtschicht 12.In the figure, 1 denotes a vacuum-tight bulb, which carries on its one end wall 2 in the interior of the bulb a luminous layer 3 that is sensitive to X-ray light, which can consist, for example, of sodium-doped cesium iodide (CsJ: Na) and which is followed by a photocathode layer 4 . At a distance of approx. 12 mm follows an electron-sensitive fluorescent screen, which consists of an electron-transmissive, light-reflecting cover 5 made of aluminum and a fluorescent layer 6. This rests on a support 7, which consists of mica and is 50 / km thick. On its free surface, the carrier 7 is provided with a coating 8 made of cesium iodide, which is 8 microns thick. Finally, a photocathode layer 9 which corresponds to layer 4 is applied to layer 8. The luminescent screen combination lying on the output side 10 opposite the input side 2, like that designated in the intermediate screen with 5 and 6, consists of a cover 11 made of aluminum and a luminescent layer 12.

Zum Betrieb des Bildverstärkers wird zur Nahfokussierung und Beschleunigung aus einer Gleichstromquelle 13 zwischen der Fotokathode 4 und der Aluminiumschicht 5 eine Spannung von 15 kV angelegt. Zum gleichen Zweck wird zwischen der Fotokathodenschicht 9 und der Aluminiumabdeckung 11 eine Spannung von 20 kV aus einer Quelle 14 angelegt.To operate the image intensifier, a voltage of 15 kV is applied between the photocathode 4 and the aluminum layer 5 for close focusing and acceleration from a direct current source 13. For the same purpose, a voltage of 20 kV from a source 14 is applied between the photocathode layer 9 and the aluminum cover 11.

Zur Erzeugung eines Röntgenbildes wird aus einer Einrichtung 15 zur Erzeugung von Röntgenstrahlen ein von einer Röntgenröhre 16 kommendes Strahlenbündel 17 auf einen Körper 18 gerichtet. Nach dem Durchdringen des Körpers 18 kommen die Strahlen aus dem Bündel 17 durch das Eingangsfenster 2 auf den Leuchtschirm 3, erzeugen dort Licht, welches auf die Fotokathode 4 einwirkt und dort Elektronen auslöst. Diese werden dann entsprechend der Andeutung durch punktierte Linien 19 auf den aus 5 und 6 bestehenden Leuchtschirm zu beschleunigt. Dort lösen die Elektronen im Sinne der erwünschten Abbildung und Verstärkung 19 erneut Licht aus, weiches durch den Träger 7 und die Belegung 8 hindurch auf die Fotokathode 9 einwirkt und dort erneut einen Elektronenstrahl 20 auslöst, der dann in dem aus 11 und 12 bestehenden Leuchtschirm Licht auslöst, das, wie durch Pfeile 21 angedeutet, von aussen beobachtet werden kann.To generate an X-ray image, a beam of rays 17 coming from an X-ray tube 16 is directed onto a body 18 from a device 15 for generating X-rays. After penetrating the body 18, the rays from the bundle 17 come through the input window 2 onto the fluorescent screen 3, where they generate light which acts on the photocathode 4 and triggers electrons there. These are then accelerated according to the indication by dotted lines 19 on the fluorescent screen consisting of 5 and 6. There, the electrons trigger light again in the sense of the desired imaging and amplification 19, which acts on the photocathode 9 through the support 7 and the coating 8 and there again triggers an electron beam 20, which then emits light in the phosphor screen consisting of 11 and 12 triggers, which, as indicated by arrows 21, can be observed from the outside.

Claims (5)

1. A multi-stage X-ray image intensifier, in which the X-ray image is converted into an electron image in an input screen (2, 3, 4), the electron image is intensified in an accelerating electric field and is subsequently rendered visible on an output screen (10, 11, 12), wherein between the end of the accelerating field and the output screen ( 10, 11,12), there is arranged at least one further accelerating electric field which starts with an intermediate screen (5 to 9) and wherein the intermediate screen (5 to 9) carries an electron-sensitive fluorescent layer (6) on a light-transmissive carrier (7) at the side facing the input screen (2, 3, 4) and a photo-cathode layer (9) at the opposite side, both the input screen (2, 3, 4) and the intermediate screen (5 to 9) having surfaces of the same material as a support for the photo-cathode layers (4, 9), characterised in that, in the case of the intermediate screen (5 to 9), material which is resistant to the photo-cathodes is disposed as a coating (8) on the carrier (7) at the side facing the photo-cathode (9); and that the surface, of the X-ray sensitive fluorescent layer (3) of the input screen (2, 3, 4), which is coated with the photo-cathode layer (4) and which is applied to a carrier (2) at its opposite side, also consists of this material.
2. An image intensifier according to claim 1, characterised in that the coating (3, 8) is a vapour- deposited layer which tightly covers the support [input window (2) and carrier (7)].
3. An image intensifier according to claim 1, characterised in that the coating (3, 8) consists of caesium iodide (Csl).
4. An image intensifier according to claim 2, characterised in that the coating (3, 8) consists of a sodium-activated caesium iodide phosphor (Csl:Na).
5. An image intensifier according to claim 4, characterised in that the resistant coating (8) of the carrier (7) of the intermediate screen has a thickness of 5 to 10 µm.
EP81100574A 1980-02-06 1981-01-27 Plural-stage vacuum x-ray image amplifier Expired EP0033894B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3004351 1980-02-06
DE19803004351 DE3004351A1 (en) 1980-02-06 1980-02-06 MULTI-STAGE VACUUM X-RAY IMAGE AMPLIFIER

Publications (2)

Publication Number Publication Date
EP0033894A1 EP0033894A1 (en) 1981-08-19
EP0033894B1 true EP0033894B1 (en) 1984-05-30

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP81100574A Expired EP0033894B1 (en) 1980-02-06 1981-01-27 Plural-stage vacuum x-ray image amplifier

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US (1) US4362933A (en)
EP (1) EP0033894B1 (en)
JP (1) JPS5843859B2 (en)
DE (2) DE3004351A1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4594566A (en) * 1984-08-30 1986-06-10 Advanced Nmr Systems, Inc. High frequency rf coil for NMR device
US4730106A (en) * 1986-12-04 1988-03-08 United States Department Of Energy Optical fiducial timing system for X-ray streak cameras with aluminum coated optical fiber ends
US4912737A (en) * 1987-10-30 1990-03-27 Hamamatsu Photonics K.K. X-ray image observing device
US5013902A (en) * 1989-08-18 1991-05-07 Allard Edward F Microdischarge image converter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2555423A (en) * 1947-04-16 1951-06-05 Sheldon Edward Emanuel Image intensifying tube
FR2161064A1 (en) * 1971-11-24 1973-07-06 Electron Physics Ltd
FR2284185A1 (en) * 1974-09-05 1976-04-02 Siemens Ag Alkali metal-antimony electro-optical emission layer - for X-ray intensifier with low antimony content, giving high quantum yield
DE2624781A1 (en) * 1975-06-04 1976-12-09 Rca Corp ELECTRON-EMITTING ELECTRODE
GB2016206A (en) * 1978-03-10 1979-09-19 Diagnostic Inform Gamma ray camera

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2851625A (en) * 1952-10-30 1958-09-09 Rca Corp Image tube
FR1474019A (en) * 1966-01-20 1967-03-24 Electronique & Physique Multistage Image Amplifier Tube Feeder
US3749920A (en) * 1971-12-03 1973-07-31 E Sheldon System for x-ray image intensification

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2555423A (en) * 1947-04-16 1951-06-05 Sheldon Edward Emanuel Image intensifying tube
FR2161064A1 (en) * 1971-11-24 1973-07-06 Electron Physics Ltd
FR2284185A1 (en) * 1974-09-05 1976-04-02 Siemens Ag Alkali metal-antimony electro-optical emission layer - for X-ray intensifier with low antimony content, giving high quantum yield
DE2624781A1 (en) * 1975-06-04 1976-12-09 Rca Corp ELECTRON-EMITTING ELECTRODE
GB2016206A (en) * 1978-03-10 1979-09-19 Diagnostic Inform Gamma ray camera

Also Published As

Publication number Publication date
JPS5843859B2 (en) 1983-09-29
DE3004351A1 (en) 1981-08-13
US4362933A (en) 1982-12-07
JPS56123655A (en) 1981-09-28
EP0033894A1 (en) 1981-08-19
DE3163788D1 (en) 1984-07-05

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