EP0168776A2 - X-ray tube - Google Patents

X-ray tube Download PDF

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Publication number
EP0168776A2
EP0168776A2 EP85108637A EP85108637A EP0168776A2 EP 0168776 A2 EP0168776 A2 EP 0168776A2 EP 85108637 A EP85108637 A EP 85108637A EP 85108637 A EP85108637 A EP 85108637A EP 0168776 A2 EP0168776 A2 EP 0168776A2
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EP
European Patent Office
Prior art keywords
target
potential
ray tube
cathode
anode
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EP85108637A
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German (de)
French (fr)
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EP0168776A3 (en
Inventor
Helge Carlsen
Hans-Erik Hjelmrodt
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Scanray AS
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Scanray AS
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Publication of EP0168776A2 publication Critical patent/EP0168776A2/en
Publication of EP0168776A3 publication Critical patent/EP0168776A3/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/14—Arrangements for concentrating, focusing, or directing the cathode ray

Definitions

  • the invention relates to an X-ray tube of the type mentioned in the preamble of the claim.
  • Such X-ray tubes are limited by the structural conditions with regard to the voltage between the cathode and the hole anode, so that the hardness of the X-ray radiation, which is dependent on the speed at which the electrons strike the target, is limited.
  • the invention has for its object to provide an X-ray tube of the type in question, in which the disadvantages mentioned do not exist, so that frequency variations of the X-ray radiation are possible without impairing the focus, in which the requirements for smoothing and stabilization hole between the cathode and / anode potential are reduced and a harder, that is higher frequency X-ray radiation can be generated.
  • This teaching is based on the basic idea of forming the X-ray beam between the cathode and the hole anode with a constant acceleration voltage between the cathode and the hole anode at a relatively low voltage, so that the electrical conditions with respect to the focusing, which are essentially determined by this voltage, are constant to keep. Thereby you can achieve a consistently high level of focus.
  • the smoothing and stabilization of this supply voltage is relatively simple and inexpensive. At the same time, this supply voltage need not be very high, which further simplifies smoothing and stabilization.
  • the invention is based on the idea of influencing the electron beam with regard to power or frequency variation in the region between the hole anode and the target, where the focusing is no longer influenced by applying an additional voltage.
  • Accelerating voltage between the hole anode and the target can also be used to supply additional power, which, however, also supply / electron beam with additional power, which is particularly advantageous in the case of electron beam welding devices.
  • this additional power supplying acceleration voltage leaves the focusing conditions largely unaffected, the requirements for smoothing this acceleration voltage are significantly reduced, so that the effort is reduced accordingly. It is even possible to use only a pulsating voltage or even an alternating voltage, depending on the desired requirements. Adjusting this acceleration voltage also has no influence on the focusing conditions, so that the frequency of the X-rays and / or the power of the electron beam striking the target can be set as desired for welding purposes.
  • the arrangement of a metallic tube between the hole anode and target is advantageous for the purpose of bundling known per se by forming a plasma.
  • This metallic tube is expediently at the potential of the hole anode or at a slightly positive potential.
  • the drawing shows, partially in section, an X-ray tube with a housing 1, which is connected to a line 2, which is connected to a pump, not shown, for lowering the pressure in the interior 3 of the X-ray tube.
  • a cathode 4 in the form of a small filament, which is bent in a V-shape and with its tip facing an anode 5 and a target 6.
  • a grid cap 7 is arranged in the region of the cathode 4, which projects into an opening 8 in the grid cap 7 and whose tip is approximately aligned with the front boundary of the opening 8. From this front boundary, the grille cap 7 widens in a conical surface 9.
  • a hole 11 runs through the hole anode 5 and continues into an interior 12 of the metallic tube 10 with a variable inside diameter.
  • a focusing coil 13 is arranged in the area of the metallic tube 10.
  • deflection coils 14 and 15 are provided, with which the electron beam can be deflected and which are of no further importance for the understanding of the invention.
  • the target 6 points to that by a dash-dotted line Line indicated axis 16 of the X-ray tube on an inclination and is held in a holder 17 which is connected via pipes 18 and 19 to a cooling source, not shown, for the purpose of cooling the target.
  • a window 20 in the housing Radially next to the surface of the target 6 there is a window 20 in the housing through which X-rays emanating from the target 6 can emerge in the area between two dashed lines 21 and 22.
  • the angle between a central axis of the emerging X-ray radiation, indicated by a broken line 23, and the surface of the target 6 is approximately f45 degrees or, in the case of an omnidirectional tube, 0 degrees.
  • the cathode 4 When the X-ray tube is in operation, the cathode 4 may be at a variable potential, for example -20 KV to -250 KV, the grid cap 7 at a potential of approximately 1-3 KV below, the hole anode 5 at zero potential and the target 6 at a variable Potential up to +250 KG.
  • the parts of the housing between these elements of the X-ray tube are of course made of insulating material, which requires no explanation.
  • the electrons emerging from the glowing cathode 4 are accelerated by the potential lying between the cathode 4 and the hole anode 5 and shoot through the hole 11 and finally through the interior 12 of the tube 10 to finally strike the surface of the target 6.
  • the electron beam is focused in a known manner by means of the focusing coil 13.
  • the pressure in the interior 3 is set such that a plasma forms inside the tube 10, in particular in the region facing the target 6, and on the way to the target, which bundles and closely guides the electron beam to the surface of the Targets leads so that there is an extremely small area of electrons and thus an extremely small extension of the radiation source is created for the radiation emerging from the window 20.
  • the invention lies between the hole anode 5 and the target 6 because of the additional use of the tube 10 in the embodiment between the end of the tube 10 and the Target 6 has a high acceleration voltage, in this case variable up to +250 KV.
  • This voltage has practically no influence on the focusing, it can therefore be variable, pulsating, changing or adjustable.
  • the voltage between the hole anode 5 and the target 6 or workpiece requires only a slight smoothing, without the focusing and thus, for example, the width of a weld seam variation in focus and is therefore subject to width variations.
  • the voltage between the hole anode 5 and the target 6 can be designed to be pulsating or alternating, in order to vary the frequency of the emerging radiation in order to blur diffraction patterns.

Abstract

An X-ray tube has a cathode, a grid, a perforated anode and a target arranged behind the perforated anode. The cathode and grid are located opposite the perforated anode at negative potentials, the potential of the grid being somewhat more negative than that of the cathode. According to the invention, the target is at a preferably positive potential which differs from the potential of the perforated anode. This potential does not affect the focusing, so that in the case of welding machines it requires little or no smoothing, while when using the X-ray tube for investigation purposes, variation or adjustability of the said voltage is possible without affecting the focusing, so that the frequency of the generated X-ray radiation can be changed or continuously varied in this way, in order to obliterate diffraction patterns, for example in the investigation of mono- crystals. <IMAGE>

Description

Die Erfindung betrifft eine Röntgenröhre der im Oberbegriff des Anspruchs genannten Art.The invention relates to an X-ray tube of the type mentioned in the preamble of the claim.

Beispielsweise aus dem Buch "Microfocal Radiography" von R.V. Ely, Academic Press 1980, ist zu entnehmen, daß Röntgenröhren der betreffenden Art mit einem Mikrofokus seit langem bekannt sind. Durch den Aufsatz "Positive-Ion Trapping in Electron Beams" von E.L. Ginzton und B.H. Wadia in der Zeitschrift "Proceedings of the I-R-E", Oktober 1955, S. 1548 bis 1554, ist es bekannt, einen Elektronenstrahl durch eine Raumladung zu bündeln. Mit einer derartigen Bündelung arbeitende Röntgenröhren wurden bereits von der Anmelderin hergestellt und vertrieben. Sie zeichnen sich durch einen außerordentlich kleinen Fokus aus, woraus sich eine wesentlich größere Auflösung von Röntgenbildern ableitet. Die in solchen Röntgenröhren verwendeten Elektronenstrahlkanonen wurden auch mit Vorteil bei Röntgenschweißgeräten verwendet.For example, from the book "Microfocal Radiography" by R.V. Ely, Academic Press 1980, it can be seen that X-ray tubes of the type in question with a microfocus have long been known. The essay "Positive-Ion Trapping in Electron Beams" by E.L. Ginzton and B.H. Wadia in the magazine "Proceedings of the I-R-E", October 1955, pp. 1548 to 1554, it is known to bundle an electron beam through a space charge. X-ray tubes working with such a bundle have already been manufactured and sold by the applicant. They are characterized by an extraordinarily small focus, from which a much greater resolution of X-ray images is derived. The electron guns used in such X-ray tubes have also been used to advantage in X-ray welding equipment.

Trotz des Vorteils des kleinen Fokus haben diese bekannten Röntgenröhren Nachteile. Um Diffraktionsmuster in Röntgenbildern, beispielsweise bei der Untersuchung von Monokristallen, zu verwischen,ist eine ständige Frequenzvariation der Röntgenstrahlung erwünscht. Diese Frequenzvariation läßt sich durch eine entsprechende Variation des zwischen Kathode und Lochanode liegenden Potentials erreichen, was jedoch zur Folge hat, daß auch die Fokussierung entsprechend variiert. Bei pulsierendem Potential zwischen Kathode und Lochanode läßt sich daher nur eine wesentlich schlechtere mittlere Fokussierung erreichen als bei Betrieb mit geglätteter Spannung.Despite the advantage of the small focus, these known X-ray tubes have disadvantages. In order to blur diffraction patterns in X-ray images, for example when examining monocrystals, a constant frequency variation of the X-rays is desirable. This frequency variation can be achieved by a corresponding variation of the potential lying between the cathode and the hole anode, but this has the consequence that the focusing also varies accordingly. With a pulsating potential between the cathode and the hole anode therefore only achieve a much poorer average focus than when operating with smoothed voltage.

Ein weiterer Nachteil ergibt sich bei diesen bekannten Röntgenröhren bei Einsatz für Elektronenstrahlschweißzwecke. Hierbei wird mit einer verhältnismäßig hohen elektrischen Leistung gearbeitet. Da es auf jeden Fall erwünscht ist, die Auftrefffläche des Elektronenstrahls auf das Target, in diesem Fall ein Werkstück, also den Fokus, möglichst klein und gleich groß zu halten, ist ein hohes Maß von Glättung hinsichtlich des Versorgungspotentials zwischen Kathode und Lochanode erforderlich. Da dieses Versorgungspotential z.B. bei 200 KV liegt, ergibt sich ein beträchtlicher Aufwand für die Glättung, um dadurch die Fokussierverhältnisse konstant und optimal zu halten. Wegen der Glättung ist aus gleichem Grunde auch eine Stabilisierung dieser Spannung erforderlich, was eine weitere Schwierigkeit bedeutet.Another disadvantage arises with these known X-ray tubes when used for electron beam welding purposes. Here, a relatively high electrical output is used. Since it is in any case desirable to keep the impact area of the electron beam on the target, in this case a workpiece, i.e. the focus, as small and as large as possible, a high degree of smoothing is necessary with regard to the supply potential between the cathode and the hole anode. Since this supply potential e.g. is 200 KV, there is a considerable effort for smoothing, in order to keep the focusing conditions constant and optimal. For the same reason, because of the smoothing, this voltage must also be stabilized, which means a further difficulty.

-Schließlich sind derartige Röntgenröhren durch die konstruktiven Verhältnisse hinsichtlich der zwischen Kathode und Lochanode liegenden Spannung begrenzt, so daß die von der Auftreffgeschwindigkeit der Elektronen auf das Target abhängige Härte der Röntgenstrahlung begrenzt ist.Finally, such X-ray tubes are limited by the structural conditions with regard to the voltage between the cathode and the hole anode, so that the hardness of the X-ray radiation, which is dependent on the speed at which the electrons strike the target, is limited.

Der Erfindung liegt die Aufgabe zugrunde, eine Röntgenröhre der betreffenden Art zu schaffen, bei der die genannten Nachteile nicht bestehen, bei der also Frequenzvariationen der Röntgenstrahlung ohne Beeinträchtigung der Fokussierung möglich sind, bei der die Anforderungen an Glättung und Stabi-Loch lisierung des zwischen Kathode und/anode liegenden Potentials verringert sind und bei der eine härtere, also höherfrequente Röntgenstrahlung erzeugbar ist.The invention has for its object to provide an X-ray tube of the type in question, in which the disadvantages mentioned do not exist, so that frequency variations of the X-ray radiation are possible without impairing the focus, in which the requirements for smoothing and stabilization hole between the cathode and / anode potential are reduced and a harder, that is higher frequency X-ray radiation can be generated.

Die der Erfindung zugrundeliegende Aufgabe wird durch die im Kennzeichen des Anspruchs 1 angegebene Lehre gelöst.The object on which the invention is based is achieved by the teaching specified in the characterizing part of claim 1.

Diese Lehre geht von dem Grundgedanken aus, den Röntgenstrahl zwischen Kathode und Lochanode mit konstanter Beschleunigungsspannung zwischen Kathode und Lochanode bei verhältnis-Spannung mäßig geringer / zu bilden, um so die elektrischen Verhältnisse hinsichtlich der Fokussierung, die im wesentlichen durch diese Spannung bestimmt sind, konstant zu halten. Dadurch läßt sich ein gleichmäßig hohes Maß an Fokussierung erzielen. Außerdem besteht der Vorteil, daß wegen der geringen Spannung die Glättung und Stabilisierung dieser Versorgungsspannung verhältnismäßig einfach und wenig aufwendig ist. Gleichzeitig braucht diese Versorgungsspannung nicht sehr hoch zu sein, wodurch sich Glättung und Stabilisierung weiter vereinfachen.This teaching is based on the basic idea of forming the X-ray beam between the cathode and the hole anode with a constant acceleration voltage between the cathode and the hole anode at a relatively low voltage, so that the electrical conditions with respect to the focusing, which are essentially determined by this voltage, are constant to keep. Thereby you can achieve a consistently high level of focus. There is also the advantage that, due to the low voltage, the smoothing and stabilization of this supply voltage is relatively simple and inexpensive. At the same time, this supply voltage need not be very high, which further simplifies smoothing and stabilization.

Insbesondere liegt aber der Erfindung der Gedanke zugrunde, sämtliche Beeinflussungen des Elektronenstrahls hinsichtlich Leistung oder Frequenzvariation im Bereich zwischen Lochanode und Target zu bewirken, wo durch Anlegen einer zusätzlichen Spannung keine Beeinflussung der Fokussierung mehr erfolgt. Auf diese Weise ist es zunächst möglich, durch bewußte Änderungen dieser zwischen Lochanode und Target liegenden Beschleunigungsspannung Frequenzvariationen der erzeugten Röntgenstrahlung zu schaffen, um so bei Verwendung der Röntgenröhre zur Erzeugung von Schattenbildern (Röntgenbildern) zu Untersuchungszwecken beispielsweise bei Monokristallen Diffraktionsmuster zu verwischen.Durch die zusätzliche Beschleuni ungsspannung zwischen Lochanode und Target läßt sich aber eiern zusätzliche Leistung zuführen, was aber auch/Elektronenstrahl zusätzliche Leistung zuführen, was insbesondere bei Elektronenstrahlschweißgeräten vorteilhaft ist. Da diese zusätzliche Leistung zuführende Beschleunigungsspannung die Fokussierverhältnisse weitgehend unbeeinflußt läßt, sind die Anforderungen an eine Glättung dieser Beschleunigungsspannung wesentlich verringert, so daß sich entsprechend auch der Aufwand verringert. Es ist sogar möglich, je nach den gewünschten Erfordernissen sogar nur mit einer pulsierenden Spannung oder gar nur einer Wechselspannung zu arbeiten. Auch eine Einstellung dieser Beschleunigungsspannung ist ohne Einfluß auf die Fokussierverhältnisse, so daß die Frequenz der Röntgenstrahlung und/oder die Leistung des auf das Target treffenden Elektronenstrahls zu Schweißzwecken beliebig einstellbar sind.In particular, however, the invention is based on the idea of influencing the electron beam with regard to power or frequency variation in the region between the hole anode and the target, where the focusing is no longer influenced by applying an additional voltage. In this way, it is first possible to create frequency variations of the generated X-ray radiation by deliberately changing this acceleration voltage lying between the hole anode and the target, so that when using the X-ray tube for producing shadow images (X-ray images) for examination purposes, for example in the case of monocrystals, the diffraction pattern is blurred Accelerating voltage between the hole anode and the target can also be used to supply additional power, which, however, also supply / electron beam with additional power, which is particularly advantageous in the case of electron beam welding devices. Since this additional power supplying acceleration voltage leaves the focusing conditions largely unaffected, the requirements for smoothing this acceleration voltage are significantly reduced, so that the effort is reduced accordingly. It is even possible to use only a pulsating voltage or even an alternating voltage, depending on the desired requirements. Adjusting this acceleration voltage also has no influence on the focusing conditions, so that the frequency of the X-rays and / or the power of the electron beam striking the target can be set as desired for welding purposes.

Es wurde zusätzlich gefunden, daß bei Anwendung der wenigstens erfindungsgemäßen Lehre die Verwendung/einer Fokussiereinrichtung im Bereich zwischen Lochanode und Target . die Fokussion zusätzlich erhöht, wobei diese Fokussion weitgehend unabhängig von der zusätzlichen Beschleunigungsspannung zwischen Lochanode und Target ist, jedenfalls wesentlich unempfindlicher als die vor Austritt des Elektronenstrahls aus dem Einfluß der Lochanode liegende Fokussiereinrichtung hinsichtlich der zwischen Kathode und Lochanode liegenden Spannung.It was additionally found that when using the teaching according to the invention at least the use / a focusing device in the region between the hole anode and the target. the focus is additionally increased, this focus being largely independent of the additional acceleration voltage between the hole anode and the target, in any case considerably less sensitive than the focusing device which lies before the electron beam emerges from the influence of the hole anode with regard to the voltage lying between the cathode and the hole anode.

Vorteilhaft ist die Anordnung einer metallischen Röhre zwischen Lochanode und Target zum Zwecke der an sich bekannten Bündelung durch Bildung eines Plasmas. Diese metallische Röhre liegt dabei zweckmäßigerweise auf dem Potential der Lochanode oder einem geringfügig positiven Potential.The arrangement of a metallic tube between the hole anode and target is advantageous for the purpose of bundling known per se by forming a plasma. This metallic tube is expediently at the potential of the hole anode or at a slightly positive potential.

Anhand der Zeichnung soll die Erfindung an einem Ausführungsbeispiel näher erläutert werden.The invention will be explained in more detail using an exemplary embodiment with reference to the drawing.

Die Zeichnung zeigt teilweise geschnitten eine Röntgenröhre mit einem Gehäuse 1, das an eine Leitung 2 angeschlossen ist, die mit einer nicht dargestellten Pumpe zur Absenkung des Druckes im Innenraum 3 der Röntgenröhre verbunden ist.The drawing shows, partially in section, an X-ray tube with a housing 1, which is connected to a line 2, which is connected to a pump, not shown, for lowering the pressure in the interior 3 of the X-ray tube.

Im Innenraum 3 befindet sich eine Kathode 4 in Form eines kleinen Glühdrahtes,der V-förmig gebogen ist und mit seiner Spitze einer Anode 5 und einem Target 6 zugewandt ist. Eine Gitterkappe 7 ist im Bereich der Kathode 4 angeordnet, die in einen Durchbruch 8 der Gitterkappe 7 ragt und mit ihrer Spitze etwa mit der vorderen Begrenzung des Durchbruchs 8 fluchtet. Von dieser vorderen Begrenzung aus erweitert sich die Gitterkappe 7 in einer Kegelfläche 9.In the interior 3 there is a cathode 4 in the form of a small filament, which is bent in a V-shape and with its tip facing an anode 5 and a target 6. A grid cap 7 is arranged in the region of the cathode 4, which projects into an opening 8 in the grid cap 7 and whose tip is approximately aligned with the front boundary of the opening 8. From this front boundary, the grille cap 7 widens in a conical surface 9.

Auf der Rückseite der Lochanode 5 befindet sich eine Röhre 10, die mit der Lochanode 5 leitend verbunden ist. Durch die Lochanode 5 verläuft ein Loch 11, das sich in einen Innenraum 12 der metallischen Röhre 10 mit variablem Innendurchmesser fortsetzt.On the back of the hole anode 5 there is a tube 10 which is conductively connected to the hole anode 5. A hole 11 runs through the hole anode 5 and continues into an interior 12 of the metallic tube 10 with a variable inside diameter.

Im Bereich der metallischen Röhre 10 ist eine Fokussierspule 13 angeordnet. Außerdem sind Ablenkspulen 14 und 15 vorgesehen, mit denen der Elektronenstrahl ablenkbar ist und die für das Verständnis der Erfindung nicht weiter von Bedeutung sind.A focusing coil 13 is arranged in the area of the metallic tube 10. In addition, deflection coils 14 and 15 are provided, with which the electron beam can be deflected and which are of no further importance for the understanding of the invention.

Das Target 6 weist zu der durch eine strichpunktierte Linie angedeuteten Achse 16 der Röntgenröhre eine Neigung auf und ist in einer Halterung 17 gehalten, die zum Zwecke der Kühlung des Targets über Rohrleitungen 18 und 19 an eine nicht gezeigte Kühlquelle angeschlossen ist.The target 6 points to that by a dash-dotted line Line indicated axis 16 of the X-ray tube on an inclination and is held in a holder 17 which is connected via pipes 18 and 19 to a cooling source, not shown, for the purpose of cooling the target.

Radial neben der Oberfläche des Targets 6 befindet sich in dem Gehäuse ein Fenster 20, durch das von dem Target 6 ausgehende Röntgenstrahlung im Bereich zwischen zwei gestrichelten Linien 21 und 22 austreten kann. Der Winkel zwischen einer durch eine gestrichelte Linie 23 angedeuteten Mittelachse der austretenden Röntgenstrahlung und der Oberfläche des Targets 6 beträgt circa f45 Grad oder im Falle einer Rundstrahlröhre 0 Grad.Radially next to the surface of the target 6 there is a window 20 in the housing through which X-rays emanating from the target 6 can emerge in the area between two dashed lines 21 and 22. The angle between a central axis of the emerging X-ray radiation, indicated by a broken line 23, and the surface of the target 6 is approximately f45 degrees or, in the case of an omnidirectional tube, 0 degrees.

Bei Betrieb der Röntgenröhre möge die Kathode 4 an einem variablen Potential, beispielsweise -20 KV bis -250 KV, liegen, die Gitterkappe 7 auf einem Potential von circa 1-3 KV darunter, die Lochanode 5 auf Nullpotential und das Target 6 auf einem variablen Potential bis +250 KG. Die Teile des Gehäuses zwischen diesen Elementen der Röntgenröhre bestehen natürlich aus isolierendem Material, was keiner Erläuterung bedarf. Die aus der glühenden Kathode 4 austretenden Elektronen werden durch das zwischen der Kathode 4 und der Lochanode 5 liegende Potential beschleunigt und schießen durch das Loch 11 und schließlich durch den Innenraum 12 der Röhre 10, um schließlich auf die Oberfläche des Targets 6 aufzutreffen. Mittels der Fokussierspule 13 wird der Elektronenstrahl in bekannter Weise fokussiert. Der Druck in dem Innenraum 3 ist so eingestellt, daß sich innerhalb der Röhre 10, insbesondere im dem Target 6 zugewandten Bereich, und auf dem Weg zu dem Target hin ein Plasma bildet, das zu einer Bündelung und engen Führung des Elektronenstrahls zu der Oberfläche des Targets hin führt, so daß dort ein äußerst geringer Flächenbereich von Elektronen beaufschlagt und damit für die aus dem Fenster 20 austretende Strahlung eine äußerst geringe Ausdehnung der Strahlungsquelle geschaffen ist.When the X-ray tube is in operation, the cathode 4 may be at a variable potential, for example -20 KV to -250 KV, the grid cap 7 at a potential of approximately 1-3 KV below, the hole anode 5 at zero potential and the target 6 at a variable Potential up to +250 KG. The parts of the housing between these elements of the X-ray tube are of course made of insulating material, which requires no explanation. The electrons emerging from the glowing cathode 4 are accelerated by the potential lying between the cathode 4 and the hole anode 5 and shoot through the hole 11 and finally through the interior 12 of the tube 10 to finally strike the surface of the target 6. The electron beam is focused in a known manner by means of the focusing coil 13. The pressure in the interior 3 is set such that a plasma forms inside the tube 10, in particular in the region facing the target 6, and on the way to the target, which bundles and closely guides the electron beam to the surface of the Targets leads so that there is an extremely small area of electrons and thus an extremely small extension of the radiation source is created for the radiation emerging from the window 20.

Erfindungsgemäß liegt zwischen der Lochanode 5 und dem Target 6 wegen der zusätzlichen Verwendung der Röhre 10 beim Ausführungsbeispiel zwischen dem Ende der Röhre 10 und dem Target 6 eine hohe Beschleunigungsspannung, in diesem Fall variabel bis +250 KV. Diese Spannung beeinflußt die Fokussierung praktisch nicht, sie kann daher variabel, pulsierend, wechselnd oder einstellbar sein. Handelt es sich um ein Elektronenstrahlschweißgerät, in welchem Falle das Target 6 das zu schweißende Werkstück bildet, so bedarf die Spannung zwischen Lochanode 5 und Target 6 bzw. Werkstück nur einer geringfügigen Glättung, ohne daß dadurch die Fokussierung und damit z.B. die Breite einer Schweißnaht Fokussionsvariationen und damit Breitenvariationen unterliegt. Handelt es sich um eine Röntgenröhre zu Untersuchungszwecken, so kann die Spannung zwischen Lochanode 5 und Target 6 pulsierend oder wechselnd ausgebildet werden, um dadurch die Frequenz der austretenden Strahlung zu variieren, um so Diffraktionsmuster zu verwischen.According to the invention lies between the hole anode 5 and the target 6 because of the additional use of the tube 10 in the embodiment between the end of the tube 10 and the Target 6 has a high acceleration voltage, in this case variable up to +250 KV. This voltage has practically no influence on the focusing, it can therefore be variable, pulsating, changing or adjustable. If it is an electron beam welding device, in which case the target 6 forms the workpiece to be welded, then the voltage between the hole anode 5 and the target 6 or workpiece requires only a slight smoothing, without the focusing and thus, for example, the width of a weld seam variation in focus and is therefore subject to width variations. If it is an X-ray tube for examination purposes, the voltage between the hole anode 5 and the target 6 can be designed to be pulsating or alternating, in order to vary the frequency of the emerging radiation in order to blur diffraction patterns.

Claims (9)

1. Röntgenröhre, mit einer Kathode, mit einem Gitter, mit einer Lochanode und mit einem hinter der Lochanode angeordneten Target, wobei die Kathode und das Gitter gegenüber der Lochanode auf negativen Potentialen liegen, von denen das des Gitters etwas negativer ist als das der Kathode, dadurch gekennzeichnet, daß das Target (6) auf einem von dem Potential der Lochanode (5) abweichenden Potential liegt.1. X-ray tube, ochanode having a cathode with a grid having an L and with a arranged behind the perforated anode target, wherein the cathode and the grid with respect to the hole anode are at negative potentials, of which the grid is somewhat more negative than that of the Cathode, characterized in that the target (6) is at a potential deviating from the potential of the hole anode (5). 2. Röntgenröhre nach Anspruch 1, dadurch gekennzeichnet, daß das Potential des Targets (6) eine Gleichspannung ist.2. X-ray tube according to claim 1, characterized in that the potential of the target (6) is a DC voltage. 3. Röntgenröhre nach Anspruch 1, dadurch gekennzeichnet, daß das Potential des Targets (6) eine pulsierende Gleichspannung oder eine Wechselspannung ist.3. X-ray tube according to claim 1, characterized in that the potential of the target (6) is a pulsating DC voltage or an AC voltage. 4. Röntgenröhre nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Potential des Targets (6) einstellbar ist.4. X-ray tube according to one of the preceding claims, characterized in that the potential of the target (6) is adjustable. 5. Röntgenröhre nach Anspruch 1, dadurch gekennzeichnet, daß sich zwischen der Lochanode (5) und dem Target (6) wenigstens eine Fokussiereinrichtung .(13) befindet.5. X-ray tube according to claim 1, characterized in that there is at least one focusing device (13) between the hole anode (5) and the target (6). 6. Röntgenröhre nach Anspruch 5, dadurch gekennzeichnet, daß die Fokussiereinrichtung (13) eine elektrostatische oder elektromagnetische Fokussiereinrichtung ist.6. X-ray tube according to claim 5, characterized in that the focusing device (13) is an electrostatic or electromagnetic focusing device. 7. Röntgenröhre nach Anspruch 1, dadurch gekennzeichnet, daß hinter der Lochanode (5), vorzugsweise im Bereich einer hinter der Lochanode (5) angeordneten magnetischen Fokussiereinrichtung (13), eine zu dem Elektronenstrahl konzentrische metallische Röhre (10) angeordnet ist.7. X-ray tube according to claim 1, characterized in that behind the hole anode (5), preferably in the region of a behind the hole anode (5) arranged magnetic focusing device (13), a concentric to the electron beam metallic tube (10) is arranged. 8. Röntgenröhre nach Anspruch 7, dadurch gekennzeichnet, daß die metallische Röhre (10) auf dem Potential der Lochanode (5) liegt.8. X-ray tube according to claim 7, characterized in that the metallic tube (10) is at the potential of the hole anode (5). 9. Röntgenröhre nach Anspruch 1, dadurch gekennzeichnet, daß das Potential zwischen Lochanode (5) und Target (6) wesentlich größer ist als das zwischen Lochanode (5) und Kathode (4).9. X-ray tube according to claim 1, characterized in that the potential between the hole anode (5) and target (6) is substantially greater than that between the hole anode (5) and cathode (4).
EP85108637A 1984-07-19 1985-07-11 X-ray tube Withdrawn EP0168776A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3426623A DE3426623A1 (en) 1984-07-19 1984-07-19 X-RAY TUBES
DE3426623 1984-07-19

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EP0168776A2 true EP0168776A2 (en) 1986-01-22
EP0168776A3 EP0168776A3 (en) 1988-03-30

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DE (1) DE3426623A1 (en)
DK (1) DK326585A (en)

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WO2000025342A1 (en) * 1998-10-27 2000-05-04 Litton Systems, Inc. X-ray tube providing variable imaging spot size

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DE4230047C1 (en) * 1992-09-08 1993-10-14 Siemens Ag Rotating anode X=ray tube for eg for medical computer tomography - has aperture plate stop in path of electron beam between cathode and anode coated with material having low atomic number.
DE4430622C2 (en) * 1994-08-29 1998-07-02 Siemens Ag Cathode system for an X-ray tube
DE19513291C2 (en) * 1995-04-07 1998-11-12 Siemens Ag X-ray tube

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US2862107A (en) * 1951-04-06 1958-11-25 Gen Electric Means for and method of controlling the generation of x-rays
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DE3222512A1 (en) * 1982-06-16 1984-03-29 Feinfocus Röntgensysteme GmbH, 3050 Wunstorf Method and device for operating an X-ray tube

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DE328834C (en) * 1920-11-09 Julius Edgar Lilienfeld Dr High vacuum roentgen tube with a diaphragm placed in the path of the cathode rays
US2862107A (en) * 1951-04-06 1958-11-25 Gen Electric Means for and method of controlling the generation of x-rays
US3783323A (en) * 1972-08-30 1974-01-01 Picker Corp X-ray tube having focusing cup with non-emitting coating
US3852605A (en) * 1972-12-27 1974-12-03 Jeol Ltd Control circuitry for preventing damage to the target of a scanning x-ray generator
DE3222512A1 (en) * 1982-06-16 1984-03-29 Feinfocus Röntgensysteme GmbH, 3050 Wunstorf Method and device for operating an X-ray tube

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000025342A1 (en) * 1998-10-27 2000-05-04 Litton Systems, Inc. X-ray tube providing variable imaging spot size
US6236713B1 (en) 1998-10-27 2001-05-22 Litton Systems, Inc. X-ray tube providing variable imaging spot size

Also Published As

Publication number Publication date
DE3426623A1 (en) 1986-01-30
DK326585D0 (en) 1985-07-18
DE3426623C2 (en) 1987-10-01
EP0168776A3 (en) 1988-03-30
DK326585A (en) 1986-01-20

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