US3710162A - X-ray tube having a rotary anode - Google Patents

X-ray tube having a rotary anode Download PDF

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Publication number
US3710162A
US3710162A US00116879A US3710162DA US3710162A US 3710162 A US3710162 A US 3710162A US 00116879 A US00116879 A US 00116879A US 3710162D A US3710162D A US 3710162DA US 3710162 A US3710162 A US 3710162A
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United States
Prior art keywords
ray tube
cylinder
anode
layer
metal
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Expired - Lifetime
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US00116879A
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English (en)
Inventor
F Bougle
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Compagnie Generale de Radiologie SA
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Compagnie Generale de Radiologie SA
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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
    • H01J35/10—Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes
    • 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
    • H01J35/10—Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes
    • H01J35/101—Arrangements for rotating anodes, e.g. supporting means, means for greasing, means for sealing the axle or means for shielding or protecting the driving
    • H01J35/1017—Bearings for rotating anodes
    • H01J35/1024—Rolling bearings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/10—Drive means for anode (target) substrate
    • H01J2235/1006—Supports or shafts for target or substrate
    • H01J2235/1013—Fixing to the target or substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/20—Arrangements for controlling gases within the X-ray tube
    • H01J2235/205—Gettering

Definitions

  • ABSTRACT I An X-ray tube having a rotary anode comprising a Foreign Appliclfioll Priority Data disc-shaped anode and a substantially cylindrical ro- Feb.
  • the present invention relates to rotary anodes for X-v ray tubes and relates, more particularly, to anodes made substantially of graphite.
  • the device in accordance with the invention enables this drawback to be overcome by achieving better heat dissipation and, moreover, allows a lighter rotor-anode assembly design so that the starting time of the rotation is shortened.
  • an X- ray tube having a rotary anode, said anode comprising a first disc-shaped portion and a second portion in the shape of a hollow cylinder, said disc being covered, at least over an area corresponding to the focal track of the tube, with a layer of refractory material generating X-rays under electron bombardment, characterized in that said two anode portions are formed integrally from a single piece graphite having a very fine structure said second cylinder-shaped portion being provided, over at least part of its internal periphery, with a hollow cylinder of a ferromagnetic material, constituting the rotor on which the rotary stator field acts.
  • This X-ray generating refractory layer may be made of a metal having a high atomic number, as for example, tungsten, rhenium, tantalum, hafnium etc, or ofalloys or of a superimposition of layers of two or more of these metals.
  • the focal track may be covered by a refractory metal carbide layer the melting point of which is considerably higher than that of the metal, resulting in the possibility of increasing the amount of useful emitted radiation by raising the admissible focal temperature.
  • the increase of the useful maximum temperature in this case is such that it more than compensates for the lower specific X-ray yield of this metal carbide which has a lower equivalent atomic number than the metal itself.
  • a further object of the present invention consists in providing one or more recesses in the graphite and depositing an absorbent getter there.
  • FIG. 1 represents a sectional view of a part of an X- ray tube in accordance with the invention
  • FIG. 2 shows an anode-rotor assembly according to an embodiment of the invention
  • FIG. 3 shows another embodiment of an anode rotor assembly according to the invention.
  • the reference 1 indicates part of the glass envelope of the X-ray tube.
  • a cylindrical tube-shaped part 2 made of a metal or alloy having practically the same coefficient of expansion as glass enables the envelope l to be welded to a first part 3 made of a nonferrous metal and designed to carry the rotor.
  • a shaft 4 carrying the rotor is connected to the first part 3 by means of two ball bearings 5 and 6.
  • the top end of the shaft 4 is fixed to a second part 7 which terminates in a disc to which the anode-rotor assembly 8 is attached.
  • the anode-rotor assembly 8 is manufactured integrally from one piece of the fine-grain, high density graphite defined in the aforementioned patent specification.
  • a graphite of this kind is obtained by compression and heating, giving rise to pseudo-vitrified material with high mechanical strength, which is also chosen to have a coefficient of expansion close to that of the X-ray emissive metal layer to be deposited upon the focal track.
  • Said assembly 8 comprises a first disc-shaped portion 9 having an oblique face, which carries the layer 10 generating the X-rays deposited on the focal track and a second portion 11 substantially in the form of a hollow cylinder.
  • the second portion 11 of the rotor 8 carries a hollow cylinder 12 of a ferromagnetic material force-fitted into its interior, this cylinder constituting the rotor proper upon which the rotary magnetic field generated by a conventional stator (not shown in FIG. 1 acts.
  • the disc constituting the first portion 9 comprises at its center a cylindrical hollow 13 which lightens it and through the base of which the rotor 8 is attached to its shaft 4.
  • the hollow 13 will advantageously contain either recesses 14 preferably disposed symmetrically about the rotor axis, or one or more annular grooves. Said recesses 14 or said grooves are filled with a material having absorbent properties, i.e. a getter, such as titanium, zirconium or tantalum. It is also possible to place additional getter pills elsewhere outside the zone of electron bombardment.
  • this kind of graphite rotor-anode assembly makes it possible to use X-ray emissive layers made of carbides of certain refractory metals having a high atomic number, like Hafnium or Titanium, so that the focal temperatureof the track can be raised and the radiated power can be thus increased.
  • the starting of the rotor is relatively slow.
  • FIGS. 2 and 3 show two embodiments of such an arrangement.
  • the anode-rotor assembly 8 is provided with a second hollow cylinder or cylindrical layer 15 made of a good conductor like copper or silver, located between the outer faceof the ferromagnetic cylinder 12 and the inner face of its cylindrical portion 11.
  • This metal cylinder 15 will provide a low resistance path for the starting current, copper for instance, having a resistivity of about 1.7 microohms. cm.
  • Cylinder 15 can be made from copper, silver or aluminum sheet or tubing, however the most advantageous way of obtaining it is by depositing the metal in a layer on the ferromagnetic cylinder 12 or on the inner or outer faces of the cylindrical rotor portion 11. This layer can be deposited by any known method as for example electrolytically, pyrolytically (deposited in gaseous phase) or by means of a plasma torch.
  • the preferred embodiment shown in FIG. 3, comprises a layer of pyrolytic graphite l6 deposited upon the outer face of the cylindrical graphite portion 11 of the assembly 8. Such a layer is obtained by inserting the cylindrical portion 11 heated to a temperature lying between 1500' 2800C into a hydrocarbon atmosphere (containing methane, for example) having a predetermined pressure.
  • a hydrocarbon atmosphere containing methane, for example
  • Such a pyrolytic graphite layer is strongly anisotropic as far as its mechanical, electrical and thermal properties are concerned. Thus its electrical resistivity in the directions perpendicular to that of its growth is much lower (comparable to that of copper) than in its growth direction.
  • Such a layer can be made even more conductive by appropriate heat treatment, such that it becomes a pseudo-monocrystal of carbon. In this case its conductivity can become up to five times that of copper.
  • the main advantage of such a pyrolytic graphite layer resides in its low specific weight, thus providing the rotor with a conducting layer without adding appreciably to its weight.
  • An X-ray tube having a rotary anode, said anode comprising a first disc-shaped portion and a second portion in the shape of a hollow cylinder, said disc being covered, at least over an area corresponding to the focal track of the tube, with a layer of refractory material generating X-rays under electron bombardment, characterized in that said two anode portions are formed integrally from a single piece graphite having a very fine structure said second cylinder-shaped portion being provided, over at least part of its internal periphery, with a hollow cylinder of a ferromagnetic material, constituting the rotor on which the rotary stator-field acts.
  • X-ray tube as claimed in claim 1, wherein said anode-rotor assembly further comprises a further hollow cylinder or cylindrical layer coaxial with both said second cylindrical portion and said ferromagnetic cylinder and made of a material which is a good electrical conductor at least in direction parallel to its surface.
  • X-ray tube as claimed in claim 3, wherein said metal cylinder or layer is placed in the vicinity of one of the faces of said secondcylinder-shaped portion.
  • X-ray tube as claimed in claim 4, wherein said metal cylinder is made up by a layer of metal deposited upon said second portion.
  • X-ray tube as claimed in claim 2, wherein said further cylinder is built up by a layer of pyrolytical graphite deposited on at least a part of the outer face of said second cylinder-shaped portion.
  • X-ray tube as claimed in claim 6, wherein said pyrolytical graphite layer is heat treated so as to provide pseudo-monocrystalline structure.
  • X-ray tube as claimed in claim 1, wherein said X- ray generating material is a refractory metal.
  • X-ray tube as claimed in claim 1, wherein said X- ray generating material is a carbide of a refractory metal.
  • X-ray tube as claimed in claim 1 wherein said disc-shaped anode portion comprises one or more recesses or grooves formed in a part thereof not subjected to the electron bombardment, and filled with material having, after its evaporation, gas absorptive properties, in other words a getter.

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  • Analysing Materials By The Use Of Radiation (AREA)
  • X-Ray Techniques (AREA)
US00116879A 1970-02-27 1971-02-19 X-ray tube having a rotary anode Expired - Lifetime US3710162A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7007192A FR2080250A5 (enrdf_load_stackoverflow) 1970-02-27 1970-02-27

Publications (1)

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US3710162A true US3710162A (en) 1973-01-09

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US00116879A Expired - Lifetime US3710162A (en) 1970-02-27 1971-02-19 X-ray tube having a rotary anode

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US (1) US3710162A (enrdf_load_stackoverflow)
FR (1) FR2080250A5 (enrdf_load_stackoverflow)
GB (1) GB1288703A (enrdf_load_stackoverflow)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3855492A (en) * 1973-11-19 1974-12-17 Machlett Lab Inc Vibration reduced x-ray anode
US4063124A (en) * 1976-03-06 1977-12-13 Siemens Aktiengesellschaft Rotating anode for X-ray tubes
FR2475800A1 (fr) * 1980-02-08 1981-08-14 Siemens Ag Tube a rayons x a anode tournante
US4326144A (en) * 1979-04-03 1982-04-20 Siemens Aktiengesellschaft Rotating anode x-ray tube
US4327305A (en) * 1978-11-20 1982-04-27 The Machlett Laboratories, Inc. Rotatable X-ray target having off-focal track coating
US4367556A (en) * 1979-10-12 1983-01-04 U.S. Philips Corporation Rotary-anode X-ray tube
US4388728A (en) * 1978-11-20 1983-06-14 The Machlett Laboratories, Incorporated Soft X-ray lithography system
US4392238A (en) * 1979-07-18 1983-07-05 U.S. Philips Corporation Rotary anode for an X-ray tube and method of manufacturing such an anode
US4920551A (en) * 1985-09-30 1990-04-24 Kabushiki Kaisha Toshiba Rotating anode X-ray tube
US5086442A (en) * 1990-03-28 1992-02-04 Siemens Aktiengesellschaft Magnetic coupling for a rotating X-ray tube
US5508118A (en) * 1992-07-03 1996-04-16 Tokyo Tungsten Co., Ltd. Rotary anode for x-ray tube
US5548628A (en) * 1994-10-06 1996-08-20 General Electric Company Target/rotor connection for use in x-ray tube rotating anode assemblies
US5652778A (en) * 1995-10-13 1997-07-29 General Electric Company Cooling X-ray tube
WO2003050840A1 (en) * 2001-12-13 2003-06-19 Koninklijke Philips Electronics N.V. Device for generating x-rays having an integrated anode and bearing member
AT410991B (de) * 1996-12-11 2003-09-25 Gen Electric Verfahren zum zusammenbauen einer rotierenden röntgenröhrenstruktur
US20080019481A1 (en) * 2005-03-02 2008-01-24 Jean-Pierre Moy Monochromatic x-ray source and x-ray microscope using one such source

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2601529C2 (de) * 1976-01-16 1982-04-29 Philips Patentverwaltung Gmbh, 2000 Hamburg Magnetische Lagerung der Drehwelle der Drehanode für eine Röntgenröhre
FR2625365B1 (fr) * 1987-12-23 1995-05-19 Thomson Cgr Tube a rayons x a anode tournante
FR3062950A1 (fr) * 2017-02-15 2018-08-17 Acerde Dispositif rotatif de production de rayons x, appareil comprenant un tel dispositif et procede de traitement d'un tel dispositif

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2336271A (en) * 1941-12-23 1943-12-07 Machlett Lab Inc Rotary anode x-ray tube

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2336271A (en) * 1941-12-23 1943-12-07 Machlett Lab Inc Rotary anode x-ray tube

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3855492A (en) * 1973-11-19 1974-12-17 Machlett Lab Inc Vibration reduced x-ray anode
US4063124A (en) * 1976-03-06 1977-12-13 Siemens Aktiengesellschaft Rotating anode for X-ray tubes
US4327305A (en) * 1978-11-20 1982-04-27 The Machlett Laboratories, Inc. Rotatable X-ray target having off-focal track coating
US4388728A (en) * 1978-11-20 1983-06-14 The Machlett Laboratories, Incorporated Soft X-ray lithography system
US4326144A (en) * 1979-04-03 1982-04-20 Siemens Aktiengesellschaft Rotating anode x-ray tube
US4392238A (en) * 1979-07-18 1983-07-05 U.S. Philips Corporation Rotary anode for an X-ray tube and method of manufacturing such an anode
US4367556A (en) * 1979-10-12 1983-01-04 U.S. Philips Corporation Rotary-anode X-ray tube
FR2475800A1 (fr) * 1980-02-08 1981-08-14 Siemens Ag Tube a rayons x a anode tournante
US4920551A (en) * 1985-09-30 1990-04-24 Kabushiki Kaisha Toshiba Rotating anode X-ray tube
US5086442A (en) * 1990-03-28 1992-02-04 Siemens Aktiengesellschaft Magnetic coupling for a rotating X-ray tube
US5508118A (en) * 1992-07-03 1996-04-16 Tokyo Tungsten Co., Ltd. Rotary anode for x-ray tube
US5548628A (en) * 1994-10-06 1996-08-20 General Electric Company Target/rotor connection for use in x-ray tube rotating anode assemblies
US5652778A (en) * 1995-10-13 1997-07-29 General Electric Company Cooling X-ray tube
AT410991B (de) * 1996-12-11 2003-09-25 Gen Electric Verfahren zum zusammenbauen einer rotierenden röntgenröhrenstruktur
WO2003050840A1 (en) * 2001-12-13 2003-06-19 Koninklijke Philips Electronics N.V. Device for generating x-rays having an integrated anode and bearing member
US20080019481A1 (en) * 2005-03-02 2008-01-24 Jean-Pierre Moy Monochromatic x-ray source and x-ray microscope using one such source

Also Published As

Publication number Publication date
GB1288703A (enrdf_load_stackoverflow) 1972-09-13
FR2080250A5 (enrdf_load_stackoverflow) 1971-11-12

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