EP0292055B1 - Radiation source for the generation of essentially monochromatic x-rays - Google Patents
Radiation source for the generation of essentially monochromatic x-rays Download PDFInfo
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- EP0292055B1 EP0292055B1 EP88200941A EP88200941A EP0292055B1 EP 0292055 B1 EP0292055 B1 EP 0292055B1 EP 88200941 A EP88200941 A EP 88200941A EP 88200941 A EP88200941 A EP 88200941A EP 0292055 B1 EP0292055 B1 EP 0292055B1
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- anode
- radiation source
- radiation
- rays
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J35/00—X-ray tubes
- H01J35/02—Details
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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
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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
- H01J35/06—Cathodes
- H01J35/066—Details of electron optical components, e.g. cathode cups
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2235/00—X-ray tubes
- H01J2235/16—Vessels
- H01J2235/165—Shielding arrangements
- H01J2235/168—Shielding arrangements against charged particles
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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
- H01J35/08—Anodes; Anti cathodes
- H01J35/112—Non-rotating anodes
- H01J35/116—Transmissive anodes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J35/00—X-ray tubes
- H01J35/02—Details
- H01J35/16—Vessels; Containers; Shields associated therewith
- H01J35/18—Windows
- H01J35/186—Windows used as targets or X-ray converters
Definitions
- the invention relates to a radiation source for generating an essentially monochromatic X-ray radiation with a cathode for generating electrons accelerated to an anode and with a conical body enclosed by the anode, which converts the X-rays impinging on it into fluorescent radiation and with its tapering end onto one Radiation leakage points.
- Such a radiation source is known from DE-OS 22 59 382.
- the monochromatic radiation is formed by the fluorescent radiation which emanates from the body when it is struck by primary X-ray radiation.
- the primary X-ray radiation is suppressed by a collimator located at a suitable location.
- the anode In the known radiation source, the anode is designed as a so-called transmission anode, ie it is struck by electrons on its outer surface and the X-ray radiation that strikes the conical body emerges from the inner surface of the anode.
- the thickness of the anode must be a compromise between the contradictory demands to absorb as many electrons as possible on the one hand and to weaken the generated X-rays as little as possible on the other. This results in relatively small thicknesses, which results in poor heat dissipation and thus a limited tube load capacity.
- the object of the present invention is to design a radiation source of the type mentioned at the outset in such a way that there is an increased thermal load capacity.
- This object is achieved in that the anode is hit on its inner surface facing the body by the electrons emitted from the cathode.
- the heat can be dissipated much better from the anode, for example by liquid cooling and / or by using a relatively thick-walled anode.
- DE-A-2 029 141 discloses an analysis arrangement in which a sample holder is partially surrounded by a cylindrical, water-cooled anode with a radiation outlet and a conical inner surface, while a cathode filament is coaxial with the radiation outlet and the sample holder lies.
- the electrons of the cathode hit the inner surface of the anode and generate primary X-rays.
- the sample attached to the sample holder is exposed to primary X-rays and emits fluorescent X-rays and secondary electrons that are measured together.
- a further development of the invention provides that the inner surface of the anode facing the body has the shape of a truncated cone jacket tapering towards the radiation exit.
- the anode consists of a solid metal block which is provided on its inner surface with a heavy-duty metal layer.
- the material of the metal block of the anode can consist of a thermally highly conductive material, for example copper, while the metal on the inner surface can be chosen with a view to the highest possible fluorescence radiation yield.
- the material for the inner surface of the anode and the outer surface of the body is selected so that the characteristic X-ray radiation emitted from the anode has an energy that is slightly greater than the K-absorption edge of the body. Since X-rays, the energy of which is slightly above the absorption edge of a material, are converted into fluorescence radiation to a particularly high percentage, this results in an increased intensity of the fluorescence radiation.
- a cylindrical metal screen which surrounds the body and which only weakens the X-ray radiation only slightly.
- the screen absorbs the secondary electrons and prevents them from generating X-rays with an energy different from the energy of the fluorescent radiation.
- the rotationally symmetrical radiation source has a cylindrical housing 1 to which a cathode arrangement 3 with a ring-shaped or spiral-shaped cathode 4 is attached via a ceramic insulator 2.
- a cathode arrangement 3 with a ring-shaped or spiral-shaped cathode 4 is attached via a ceramic insulator 2.
- an electron beam indicated by the dashed lines 4a, is emitted, which strikes the inner surface of an anode, which is shaped like the shell of a truncated cone. This results in a relatively uniform distribution of the electrons on the inner surface of the anode.
- the anode consists of a metal block 5a made of a thermally highly conductive material, preferably copper, which is coated on its inner surface with a heavy-duty metal layer, in which X-rays are generated by the electron bombardment.
- the X-ray radiation strikes a target 7 through a thin cylindrical screen 6, which is conical on its side facing away from the cathode and converts the primary radiation striking it into essentially monochromatic fluorescent radiation.
- the screen 6, which carries the target 7, has the task of keeping scattered electrons away from the target 7. These stray electrons would generate an undesirable bremsradiation spectrum when they hit the target 7.
- the screen 6 absorbs too much primary X-ray radiation and on the other hand even emits X-radiation due to stray or secondary electrons, the screen 6 is as thin-walled as is just permitted for mechanical reasons and consists of a low-atom material, e.g. Titanium.
- the primary X-ray radiation emanating from the anode 5a, 5b is suppressed by a collimator arrangement 8, in the center of which the screen 6 is attached in a vacuum-tight manner.
- the collimator consists of a radiation-absorbing material or a plurality of plates of such a material which are offset with respect to one another in the direction of the axis of symmetry, the thickness of the collimator or the distance between the outer plates of this collimator being selected such that the anode starts primary X-ray radiation must hit the collimator before it reaches the radiation exit 9.
- the energy of the fluorescence radiation depends on the material of the target. If tantalum is chosen as the material, the energy of the fluorescent radiation is 57.5 keV (K ⁇ 1 line). If a fluorescence radiation with higher or lower energy is to be generated, the tantalum target must be replaced by a target which consists of an element or an alloy with a higher or lower atomic number.
- the tube voltage (expressed in kV) must be about twice as high as the energy of the fluorescent radiation (expressed in keV).
- it is expedient to detachably e.g. by a screw connection to connect to the screen.
- the screen must be designed so that it hermetically seals the inside of the evacuated housing of the radiation source to the outside
- the layer 5b in which the primary X-ray radiation is generated, has a high atomic number and is expediently chosen such that the energy of the characteristic radiation generated in this layer lies slightly above the K absorption edge of the target 7, because this results in a particularly good implementation in fluorescence radiation. If the target consists of tantalum (K absorption edge at 67.4 keV), this condition is met by a layer 5b of gold (K ⁇ line at 68.8 keV).
- the layer 5b is preferably applied to a solid metal block 5a made of copper.
- the back of this copper block is cooled by a cooling liquid which flows into a cavity 10, which is hermetically sealed from the inside of the tube, around the copper block from the outside in a manner not shown in detail.
- a cooling liquid which flows into a cavity 10, which is hermetically sealed from the inside of the tube, around the copper block from the outside in a manner not shown in detail.
- water is preferably used as the cooling liquid.
- a metal block enclosed by a cavity for cooling it is also possible to use a metal block in which cooling channels, for example in spiral form, have already been incorporated. With a suitable design, this allows the cooling surface and thus also the maximum electrical power that can be supplied to be increased.
- the fluorescence radiation generated on the target 7 is not completely monochromatic. This is because other lines besides the desired K ⁇ lines are excited, e.g. the higher energy Kß line or L lines with much lower energy.
- the Kß line can be suppressed by a radiation filter arranged in the radiation outlet, which consists of a material whose absorption edge lies between the K ⁇ and the Kß line.
- filters made of ytterbium or thulium are suitable as radiation filters.
- the soft lines can optionally be suppressed by the same filter or by a filter made of a material with a lower atomic number, which is dimensioned such that the desired K ⁇ line is only slightly weakened, while the L lines are largely suppressed.
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- X-Ray Techniques (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
Abstract
Description
Die Erfindung betrifft eine Strahlenquelle zur Erzeugung einer im wesentlichen monochromatischen Röntgenstrahlung mit einer Kathode zur Erzeugung von auf eine Anode beschleunigten Elektronen und mit einem von der Anode umschlossenen kegelförmigen Körper, der auf ihn auftreffende Röntgenstrahlung in Fluoreszenzstrahlung umsetzt und der mit seinem sich verjüngenden Ende auf einen Strahlenaustritt weist.The invention relates to a radiation source for generating an essentially monochromatic X-ray radiation with a cathode for generating electrons accelerated to an anode and with a conical body enclosed by the anode, which converts the X-rays impinging on it into fluorescent radiation and with its tapering end onto one Radiation leakage points.
Eine solche Strahlenquelle ist aus der DE-OS 22 59 382 bekannt. Die monochromatische Strahlung wird bei dieser Strahlenquelle durch die Fluoreszenzstrahlung gebildet, die von dem Körper ausgeht, wenn er durch primäre Röntgenstrahlung getroffen wird. Die primäre Röntgenstrahlung wird durch einen an geeigneter Stelle befindlichen Kollimator unterdrückt.Such a radiation source is known from DE-OS 22 59 382. In this radiation source, the monochromatic radiation is formed by the fluorescent radiation which emanates from the body when it is struck by primary X-ray radiation. The primary X-ray radiation is suppressed by a collimator located at a suitable location.
Bei der bekannten Strahlenquelle ist die Anode als sogenannte Transmissionsanode ausgebildet, d.h. sie wird auf ihrer Außenfläche von Elektronen getroffen und die Röntgenstrahlung, die auf den kegelförmigen Körper auftrifft, tritt aus der Innenfläche der Anode aus. Die Dicke der Anode muß ein Kompromiß sein zwischen den gegensätzlichen Forderungen, einerseits möglichst alle Elektronen zu absorbieren und andererseits die erzeugte Röntgenstrahlung möglichst wenig zu schwächen. Dabei ergeben sich relativ geringe Dicken, woraus eine schlechte Wärmeabfuhr und damit eine begrenzte Röhrenbelastbarkeit resultieren.In the known radiation source, the anode is designed as a so-called transmission anode, ie it is struck by electrons on its outer surface and the X-ray radiation that strikes the conical body emerges from the inner surface of the anode. The thickness of the anode must be a compromise between the contradictory demands to absorb as many electrons as possible on the one hand and to weaken the generated X-rays as little as possible on the other. This results in relatively small thicknesses, which results in poor heat dissipation and thus a limited tube load capacity.
Aufgabe der vorliegenden Erfindung ist es, eine Strahlenquelle der eingangs genannten Art so auszugestalten, daß sich eine erhöhte thermische Belastbarkeit ergibt.The object of the present invention is to design a radiation source of the type mentioned at the outset in such a way that there is an increased thermal load capacity.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß die Anode auf ihrer dem Körper zugewandten Innenfläche von den aus der Kathode emittierten Elektronen getroffen wird.This object is achieved in that the anode is hit on its inner surface facing the body by the electrons emitted from the cathode.
Da bei dieser Bauform der Anode nur deren Innenfläche dem Elektronenbeschuß ausgesetzt und Ausgangspunkt der Röntgenstrahlung ist, kann die Wärme wesentlich besser aus der Anode abgeführt werden, beispielsweise durch eine Flüssigkeitskühlung und/oder dadurch, daß eine relativ dickwandige Anode verwendet wird.Since in this design the anode only its inner surface is exposed to the electron bombardment and the starting point of the X-rays, the heat can be dissipated much better from the anode, for example by liquid cooling and / or by using a relatively thick-walled anode.
An sich ist aus der Schrift DE-A-2 029 141 eine Analyseanordnung bekannt, bei der ein Probenhalter teilweise von einer zylindrischen, wassergekühlten Anode mit einem Strahlenaustritt und einer kegelförmigen Innenfläche umschlossen ist, während ein Kathoden-Glühfaden koaxial gegenüber dem Strahlenaustritt und dem Probenhalter liegt.DE-A-2 029 141 discloses an analysis arrangement in which a sample holder is partially surrounded by a cylindrical, water-cooled anode with a radiation outlet and a conical inner surface, while a cathode filament is coaxial with the radiation outlet and the sample holder lies.
Die Elektronen der Kathode treffen auf die Innenfläche der Anode und erzeugen eine primäre Röntgenstrahlung. Die auf dem Probenhalter befestigte Probe ist der primären Röntgenstrahlung ausgesetzt und emittiert fluoreszierende Röntgenstrahlung und sekundäre Elektronen, die zusammen gemessen werden.The electrons of the cathode hit the inner surface of the anode and generate primary X-rays. The sample attached to the sample holder is exposed to primary X-rays and emits fluorescent X-rays and secondary electrons that are measured together.
Eine Weiterbildung der Erfindung sieht vor, daß die dem Körper zugewandte Innenfläche der Anode die Form eines sich zum Strahlenaustritt hin verjüngenden Kegelstumpfmantels aufweist. Bei dieser Ausgestaltung, bei der das sich verjüngende Ende der Anode dem Strahlenaustritt und das sich erweiternde Ende der Kathode zugewandt ist, ergibt sich eine relativ gleichmäßige Verteilung der Elektronen über die Anodenfläche, so daß auch die thermische Belastbarkeit vergleichmäßigt wird.A further development of the invention provides that the inner surface of the anode facing the body has the shape of a truncated cone jacket tapering towards the radiation exit. With this configuration, in which the tapered end of the anode faces the radiation exit and the widening end of the cathode, the electrons are distributed relatively evenly over the anode surface, so that the thermal load capacity is also made more uniform.
Eine andere Weiterbildung sieht vor, daß die Anode aus einem massiven Metallblock besteht, der auf seiner Innenfläche mit einer schweratomigen Metallschicht versehen ist. Das Material des Metallblocks der Anode kann dabei aus einem thermisch gut leitenden Werkstoff bestehen, beispielsweise Kupfer, während das Metall auf der Innenfläche im Hinblick auf eine möglichst hohe Fluoreszenzstrahlungsausbeute gewählt werden kann.Another development provides that the anode consists of a solid metal block which is provided on its inner surface with a heavy-duty metal layer. The material of the metal block of the anode can consist of a thermally highly conductive material, for example copper, while the metal on the inner surface can be chosen with a view to the highest possible fluorescence radiation yield.
Eine andere Weiterbildung sieht vor, daß das Material für die Innenfläche der Anode und die Außenfläche des Körpers so gewählt ist, daß die aus der Anode emittierte charakteristische Röntgenstrahlung eine Energie besitzt, die geringfügig größer ist als die K-Absorptionskante des Körpers. Da Röntgenstrahlung, deren Energie geringfügig oberhalb der Absorptionskante eines Materials liegt, in diesem zu einem besonders hohen Prozentsatz in Fluoreszenzstrahlung umgesetzt wird, ergibt sich dadurch eine vergrößerte Intensität der Fluoreszenzstrahlung.Another development provides that the material for the inner surface of the anode and the outer surface of the body is selected so that the characteristic X-ray radiation emitted from the anode has an energy that is slightly greater than the K-absorption edge of the body. Since X-rays, the energy of which is slightly above the absorption edge of a material, are converted into fluorescence radiation to a particularly high percentage, this results in an increased intensity of the fluorescence radiation.
Nach einer anderen Weiterbildung ist vorgesehen, daß sich zwischen der Anode und dem Körper ein den Körper umschließender zylinderförmiger Metallschirm befindet, der die Röntgenstrahlung nur geringfügig schwächt. Der Schirm absorbiert die Sekundärelektronen und verhindert, daß dadurch in dem Körper Röntgenstrahlung mit einer von der Energie der Fluoreszenzstrahlung abweichenden Energie erzeugt wird.According to another development, it is provided that between the anode and the body there is a cylindrical metal screen which surrounds the body and which only weakens the X-ray radiation only slightly. The screen absorbs the secondary electrons and prevents them from generating X-rays with an energy different from the energy of the fluorescent radiation.
Die Erfindung wird nachstehend anhand der Zeichnung näher erläutert, die einen Querschnitt durch einen Teil einer erfindungsgemäßen Strahlenquelle zeigt.The invention is explained in more detail below with reference to the drawing, which shows a cross section through part of a radiation source according to the invention.
Die rotationssymmetrisch ausgebildete Strahlenquelle besitzt ein zylinderförmiges Gehäuse 1, an dem über einen Keramikisolator 2 eine Kathodenanordnung 3 mit einer ring-oder spiralförmigen Kathode 4 befestigt ist. Im Betriebszustand wird aus der Kathode ein durch die gestrichelten Linien 4a angedeutetes Elektronenbündel emittiert, das auf die Innenfläche einer Anode trifft, die wie der Mantel eines Kegelstumpfes geformt ist. Dadurch ergibt sich eine relativ gleichmäßige Verteilung der Elektronen auf der Anodeninnenfläche.The rotationally symmetrical radiation source has a cylindrical housing 1 to which a cathode arrangement 3 with a ring-shaped or spiral-
Die Anode besteht aus einem Metallblock 5a aus thermisch gut leitendem Material, vorzugsweise Kupfer, das auf seiner Innenfläche mit einer schweratomigen Metallschicht beschichtet ist, in der durch den Elektronenbeschuß Röntgenstrahlung entsteht.The anode consists of a metal block 5a made of a thermally highly conductive material, preferably copper, which is coated on its inner surface with a heavy-duty metal layer, in which X-rays are generated by the electron bombardment.
Die Röntgenstrahlung trifft durch einen dünnen zylindrischen Schirm 6 hindurch auf ein Target 7, das auf seiner von der Kathode abgewandten Seite kegelförmig gestaltet ist und die auf ihn auftreffende Primärstrahlung in im wesentlichen monochromatische Fluoreszenzstrahlung umsetzt.The X-ray radiation strikes a
Der Schirm 6, der das Target 7 trägt, hat die Aufgabe, Streuelektronen vom Target 7 fernzuhalten. Diese Streuelektronen würden beim Auftreffen auf das Target 7 ein unerwünschtes Bremsstrahlungsspektrum erzeugen. Um zu vermeiden, daß einerseits der Schirm 6 zuviel primäre Röntgenstrahlung absorbiert und andererseits durch auftreffende Streu- oder Sekundärelektronen selbst Röntgenstrahlung emittiert, ist der Schirm 6 so dünnwandig wie aus mechanischen Gründen gerade noch zulässig und besteht aus einem niederatomigen Material, z.B. Titan.The screen 6, which carries the
Das offene Ende des Schirms, dem die Spitze des kegelförmigen Targets 7 zugewandt ist, bildet den Strahlenaustritt 9 für die erzeugte Fluoreszenzstrahlung. Die von der Anode 5a, 5b ausgehende primäre Röntgenstrahlung wird von einer Kollimatoranordnung 8 unterdrückt, in deren Zentrum der Schirm 6 vakuumdicht angebracht ist. Der Kollimator besteht aus einem strahlenabsorbierenden Material oder mehreren in Richtung der Symmetrieachse gegeneinander versetzten Platten aus einem solchen Material, wobei die Dicke des Kollimators bzw. der Abstand der äußeren Platten dieses Kollimators so gewählt sind, daß von der Anode ausgehende primäre Röntgenstrahlung auf den Kollimator treffen muß, bevor sie den Strahlenaustritt 9 erreicht.The open end of the screen, which the tip of the
Die Energie der Fluoreszenzstrahlung hängt von dem Material des Targets ab. Wenn Tantal als Material gewählt wird, ergibt sich eine Energie der Fluoreszenzstrahlung von 57,5 keV (Kα₁-Linie). Wenn eine Fluoreszenzstrahlung mit höherer oder niedrigerer Energie erzeugt werden soll, muß das Tantaltarget durch eine Target ersetzt werden, das aus einem Element oder einer Legierung mit höherer bzw. niedrigerer Ordnungszahl besteht. Die Röhrenspannung (ausgedrückt in kV) muß dabei jeweils etwa doppelt so groß sein wie die Energie der Fluoreszenzstrahlung (ausgedrückt in keV). Um zwecks Erzeugung von monochromatischer Strahlung mit unterschiedlicher Wellenlänge aus unterschiedlichem Material bestehende Targets verwenden zu können, ist es zweckmäßig, das Target lösbar, z.B. durch eine Schraubverbindung, mit dem Schirm zu verbinden. Der Schirm muß dabei so gestaltet sein, daß er das Innere des evakuierten Gehäuses der Strahlenquelle hermetisch nach außen hin abschließtThe energy of the fluorescence radiation depends on the material of the target. If tantalum is chosen as the material, the energy of the fluorescent radiation is 57.5 keV (Kα₁ line). If a fluorescence radiation with higher or lower energy is to be generated, the tantalum target must be replaced by a target which consists of an element or an alloy with a higher or lower atomic number. The tube voltage (expressed in kV) must be about twice as high as the energy of the fluorescent radiation (expressed in keV). In order to be able to use targets made of different materials for the purpose of generating monochromatic radiation with different wavelengths, it is expedient to detachably, e.g. by a screw connection to connect to the screen. The screen must be designed so that it hermetically seals the inside of the evacuated housing of the radiation source to the outside
Die Schicht 5b, in der die primäre Röntgenstrahlung erzeugt wird, hat eine hohe Ordnungszahl und ist zweckmäßigerweise so gewählt, daß die Energie der in dieser Schicht erzeugten charakteristischen Strahlung geringfügig oberhalb der K-Absorptionskante des Targets 7 liegt, weil sich dabei eine besonders gute Umsetzung in Fluoreszenzstrahlung ergibt. Wenn das Target aus Tantal besteht (K-Absorptionskante bei 67,4 keV), wird diese Bedingung durch eine Schicht 5b aus Gold (Kα-Linie bei 68,8 keV) erfüllt.The
Wie bereits erwähnt, ist die Schicht 5b auf einen massiven Metallblock 5a vorzugsweise aus Kupfer aufgebracht. Die Rückseite dieses Kupferblocks wird von einer Kühlflüssigkeit gekühlt, die in einen zum Röhreninnern hin hermetisch abgedichteten Hohlraum 10 um den Kupferblock herum in nicht näher dargestellter Weise von außen einströmt. Da die Anode 5a, 5b ebenso wie das Gehäuse 1 und der Kollimator 8 Massepotential führen, wird als Kühlflüssigkeit vorzugsweise Wasser eingesetzt. Anstelle eines von einem Hohlraum für die Kühlung umschlossenen Metallblocks kann auch ein Metallblock eingesetzt werden, in den bereits Kühlkanäle, beispielsweise in Spiralform, eingearbeitet sind. Dadurch läßt sich bei geeigneter Auslegung die Kühlfläche und damit auch die maximal zuführbare elektrische Leistung vergrößern.As already mentioned, the
Die auf dem Target 7 erzeugte Fluoreszenzstrahlung ist nicht völlig monochromatisch. Dies liegt daran, daß außer der erwünschten Kα-Linien auch andere Linien angeregt werden, z.B. die höherenergetische Kß-Linie oder L-Linien mit wesentlich niedrigerer Energie. Die Kß-Linie kann durch ein im Strahlenaustritt angeordnetes Strahlenfilter unterdrückt werden, das aus einem Material besteht, dessen Absorptionskante zwischen der Kα- und der Kß-Linie liegt. Bei einem Tantaltarget eignen sich als Strahlenfilter Filter aus Ytterbium oder Thulium. Die weichen Linien können gegebenenfalls durch das gleiche Filter oder durch ein Filter aus einem Material mit einer niedrigeren Ordnungszahl unterdrückt werden, das so bemessen ist, daß die erwünschte Kα-Linie nur unwesentlich geschwächt wird, während die L-Linien weitgehend unterdrückt sind.The fluorescence radiation generated on the
Claims (12)
- A radiation source for generating essentially monochromatic X-rays comprising a cathode (3,4) for generating electrons which are accelerated onto anode (5a, 5b) and also comprising a conical member (7) which is enclosed by the anode and which converts X-rays incident thereon into fluorescence radiation, the apex of said conical member being directed towards a radiation exit, characterized in that the inner surface (5b) of the anode which faces the member (7) is struck by the electrons emitted by the cathode (4).
- A radiation source as claimed in Claim 1, characterized in that the cathode (4) is arranged at the side which is remote from the radiation exit and has annular or spiral shape.
- A radiation source as claimed in any one of the preceding Claims, characterized in that the inner surface (5b) of the anode which faces the member is shaped as a truncated cone which is tapered towards the radiation exit.
- A radiation source as claimed in any one of the Claims 1 to 3, characterized in that the outer surface of the anode can be cooled by means of a cooling liquid.
- A radiation source as claimed in any one of the preceding Claims, characterized in that the cathode is maintained at a negative high voltage potential and the anode is maintained at ground potential, the cooling liquid being water.
- A radiation source as claimed in any one of the preceding Claims, characterized in that the anode consists of a solid metal block (5a), the inner surface of which is provided with a heavy-atom metal layer (5b).
- A radiation source as claimed in any one of the preceding Claims, characterized in that the material for the inner surface of the anode and the outer surface of the member is chosen so that the energy of the characteristic X-rays emitted by the anode is slightly higher than the K-absorption edge of the outer surface of the member.
- A radiation source as claimed in Claim 7, characterized in that the anode is made of gold, at least at the area of the inner surface, the member being made of tantalum.
- A radiation source as claimed in any one of the Claims 1 to 8, characterized in that between the anode and the member there is arranged a cylindrical metal shield (6) which encloses the member and which attenuates the X-rays only slightly.
- A radiation source as claimed in Claim 9, characterized in that the shield (6) supports the member (7) and seals the housing of the radiation source in a vacuumtight manner.
- A radiation source as claimed in Claim 9, characterized in that the shield (6) opens towards the outside, the member (7) being detachably connected to the shield.
- A radiation source as claimed in any one of the preceding Claims, characterized in that in the radiation exit there is arranged a filter (9) which is made of a material whose absorption edge is situated between the Kα-line and the Kβ-line of the member.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT88200941T ATE74690T1 (en) | 1987-05-18 | 1988-05-11 | RADIATION SOURCE FOR PRODUCING SUBSTANTIALLY MONOCHROMATIC X-RAY RADIATION. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3716618 | 1987-05-18 | ||
| DE19873716618 DE3716618A1 (en) | 1987-05-18 | 1987-05-18 | RADIATION SOURCE FOR GENERATING AN ESSENTIAL MONOCHROMATIC X-RAY RADIATION |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0292055A2 EP0292055A2 (en) | 1988-11-23 |
| EP0292055A3 EP0292055A3 (en) | 1989-04-19 |
| EP0292055B1 true EP0292055B1 (en) | 1992-04-08 |
Family
ID=6327798
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP88200941A Expired - Lifetime EP0292055B1 (en) | 1987-05-18 | 1988-05-11 | Radiation source for the generation of essentially monochromatic x-rays |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4903287A (en) |
| EP (1) | EP0292055B1 (en) |
| JP (1) | JP2747295B2 (en) |
| AT (1) | ATE74690T1 (en) |
| DE (2) | DE3716618A1 (en) |
Families Citing this family (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0432568A3 (en) * | 1989-12-11 | 1991-08-28 | General Electric Company | X ray tube anode and tube having same |
| DE4017002A1 (en) * | 1990-05-26 | 1991-11-28 | Philips Patentverwaltung | Monochromatic X=radiation source |
| DE4215343A1 (en) * | 1992-05-09 | 1993-11-11 | Philips Patentverwaltung | Filter method for an X-ray system and arrangement for carrying out such a filter method |
| US5433771A (en) * | 1994-04-25 | 1995-07-18 | Westinghouse Electric Corporation | Hot gas filtration system fail-safe and thermal regeneration device |
| DE19509006C2 (en) * | 1995-03-13 | 1998-11-05 | Siemens Ag | X-ray tube |
| DE19544203A1 (en) * | 1995-11-28 | 1997-06-05 | Philips Patentverwaltung | X-ray tube, in particular microfocus X-ray tube |
| JPH11288678A (en) * | 1998-02-10 | 1999-10-19 | Siemens Ag | Fluorescence x-ray source |
| DE19808342C1 (en) * | 1998-02-27 | 1999-08-19 | Siemens Ag | Variable high-flux fluorescence X=ray source which can be switched off |
| RU2161843C2 (en) * | 1999-02-17 | 2001-01-10 | Кванта Вижн, Инк. | Point high-intensity source of x-ray radiation |
| DE10251635A1 (en) | 2002-11-06 | 2004-05-27 | Feinfocus Röntgen-Systeme GmbH | X-ray tube, in particular microfocus X-ray tube |
| JP2007503703A (en) * | 2003-05-19 | 2007-02-22 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | X-ray fluorescence source |
| US7200203B2 (en) * | 2004-04-06 | 2007-04-03 | Duke University | Devices and methods for targeting interior cancers with ionizing radiation |
| JP4738189B2 (en) * | 2006-02-01 | 2011-08-03 | 東芝電子管デバイス株式会社 | X-ray source and fluorescent X-ray analyzer |
| JP2007207539A (en) * | 2006-02-01 | 2007-08-16 | Toshiba Corp | X-ray source and fluorescent x-ray analysis system |
| WO2007088934A1 (en) * | 2006-02-01 | 2007-08-09 | Toshiba Electron Tubes & Devices Co., Ltd. | X-ray source, and fluorescent x-ray analyzing device |
| US8331534B2 (en) | 2009-04-16 | 2012-12-11 | Silver Eric H | Monochromatic X-ray methods and apparatus |
| TWI555511B (en) | 2010-12-07 | 2016-11-01 | 和鑫生技開發股份有限公司 | A transmission tpye x-ray tube and a reflection type x-ray tube |
| CN103094030A (en) * | 2011-10-28 | 2013-05-08 | 和鑫生技开发股份有限公司 | Transmission type x-ray tube and reflection type x-ray tube |
| US9368316B2 (en) * | 2013-09-03 | 2016-06-14 | Electronics And Telecommunications Research Institute | X-ray tube having anode electrode |
| KR20240055138A (en) | 2017-05-19 | 2024-04-26 | 이매진 싸이언티픽, 인크. | Monochromatic x-ray imaging systems and methods |
| CA3129632A1 (en) | 2018-02-09 | 2019-08-15 | Imagine Scientific, Inc. | Monochromatic x-ray imaging systems and methods |
| US10818467B2 (en) | 2018-02-09 | 2020-10-27 | Imagine Scientific, Inc. | Monochromatic x-ray imaging systems and methods |
| WO2020056281A1 (en) | 2018-09-14 | 2020-03-19 | Imagine Scientific, Inc. | Monochromatic x-ray component systems and methods |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1655455A (en) * | 1923-09-29 | 1928-01-10 | Gen Electric | X-ray apparatus |
| US2309566A (en) * | 1940-09-09 | 1943-01-26 | Gen Electric X Ray Corp | Window for X-ray tubes |
| US2343730A (en) * | 1942-11-30 | 1944-03-07 | Gen Electric X Ray Corp | X-ray tube |
| US3567928A (en) * | 1969-06-12 | 1971-03-02 | Du Pont | Fluorescent analytical radiation source for producing soft x-rays and secondary electrons |
| GB1443048A (en) * | 1972-12-05 | 1976-07-21 | Strahlen Umweltforsch Gmbh | X-ray source |
| JPS542084A (en) * | 1977-06-02 | 1979-01-09 | Philips Corp | Rotary anode xxray tube |
-
1987
- 1987-05-18 DE DE19873716618 patent/DE3716618A1/en not_active Withdrawn
-
1988
- 1988-05-11 DE DE8888200941T patent/DE3869829D1/en not_active Expired - Lifetime
- 1988-05-11 AT AT88200941T patent/ATE74690T1/en active
- 1988-05-11 EP EP88200941A patent/EP0292055B1/en not_active Expired - Lifetime
- 1988-05-16 JP JP63117155A patent/JP2747295B2/en not_active Expired - Lifetime
- 1988-05-16 US US07/194,631 patent/US4903287A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE3869829D1 (en) | 1992-05-14 |
| EP0292055A3 (en) | 1989-04-19 |
| US4903287A (en) | 1990-02-20 |
| JP2747295B2 (en) | 1998-05-06 |
| EP0292055A2 (en) | 1988-11-23 |
| JPS63304557A (en) | 1988-12-12 |
| DE3716618A1 (en) | 1988-12-08 |
| ATE74690T1 (en) | 1992-04-15 |
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