US3885179A - X-ray tube - Google Patents

X-ray tube Download PDF

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Publication number
US3885179A
US3885179A US443864A US44386474A US3885179A US 3885179 A US3885179 A US 3885179A US 443864 A US443864 A US 443864A US 44386474 A US44386474 A US 44386474A US 3885179 A US3885179 A US 3885179A
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US
United States
Prior art keywords
cathode
ray tube
ray
anode
ions
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US443864A
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English (en)
Inventor
Rudolf Friedel
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Siemens AG
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Siemens AG
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Filing date
Publication date
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Publication of US3885179A publication Critical patent/US3885179A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/24—Tubes wherein the point of impact of the cathode ray on the anode or anticathode is movable relative to the surface thereof
    • H01J35/30—Tubes wherein the point of impact of the cathode ray on the anode or anticathode is movable relative to the surface thereof by deflection of the cathode ray
    • H01J35/305—Tubes wherein the point of impact of the cathode ray on the anode or anticathode is movable relative to the surface thereof by deflection of the cathode ray by using a rotating X-ray tube in conjunction therewith
    • 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

Definitions

  • the load capacity of a rotary anode in short time space is determined by the greatest permissible focal point temperature, which is limited by reaching the melting point of the anode material.
  • the maximum focal point temperature must be considerably lower to provide a stable tube operation and sufficient life duration.
  • Anodes can be dirtied" during manufacture, further treatment and also during operation in the tube, for example, by coatings on the outer surface which have a higher steam pressure than the anode material.
  • the damage thereby produced appears typically as periodic meltings of the focal point path which are produced in the stated manner in combination with the generator (inner resistance, capacities). This problem becomes substantially more important for tubes with high output since the inner resistance of the generator must be held small due to the necessity select as low as possible the empty run voltage for technical and expense reasons, and even eliminate the inner resistance in wide operational ranges.
  • high load X-ray tubes have arrangements whereby electrons have the form of a hollow ray. Furthermore, a special striking surface for ions is provided in the center of the cathode for absorbing the ionic strike penetrating into the ray, instead of allowing it to strike the part emitting the electrons.
  • the cathode must also have a special construction with a striking section for ions enclosed by the electron source or the tubular electronic path. In addition, in this construction the cathode body is located only partially in the vertical projection of the ring-shaped focal point, it also goes past it. Parts of the cathode emitting electrons are also struck by the projection, so that the abovementioned damaging effects can still take place, at least partly.
  • An object of the present invention is to provide constructive means which would eliminate the abovementioned detrimental cathode back effect, which would provide greater operational safety of X-ray tubes used in medical field and which would increase their load capacity.
  • the striking location of the ions is a plate which melts with difficulty and is well heat conducting, such as a plate of tungsten, having a thickness of 0.5 to 5 mm (FIGS. 3, 4, 5 and 7).
  • the thickness of the plate is of less importance since it is only important for stability and heat capacity. It can consist of tungsten, molybdenum or tantalum.
  • An improvement can be provided if the plate is placed into the cathode body (FIG. 4).
  • the recess should have at least approximately the shape of the focal point. Due to this arrangement despite the high melting point and small gas pressure of tungsten, etc., the tungsten gas produced by the striking ions can not get into the range of the electronic ray or to locations which would affect the high voltage firmness of the tube.
  • the cathode head can be also held entirely out of the projection line of the focal point (FIG. 6).
  • a complicated cathode system for example, an electronic gun which has magnetic and electric lenses causing a sharply bundled electronic flat ray to drop upon the anode at an inclination, and to provide a separate ion receiving system.
  • Electrons produced by a heat coil or some other electronic emitter are deviated by an electric field to bent half-circular paths so that the outgoing direction and the striking direction of the electronic ray upon the anode differ from each other by more than 0 and a maximum of This provides that the heating coil is even more effectively protected from ionic striking.
  • the same effect is produced by deviating the ions by means of a permanent or electric magnet (FIG. 5).
  • the striking plate consists of tantalum, zirconium, titanium, etc., when the plate is heating during ionic striking in addition a getter effect is produced which is advantageous for the operation of the tube.
  • the space in which the plate is located is enclosed by metallic walls, so that various effects, for example, the coating of walls with metal, are limited to this space and cause no dam age.
  • FIG. 1 is a side view of an X-ray tube.
  • FIG. 2 is a diagrammatic section extending transversely to FIG. 1 through the cathode and anode of the tube shown therein.
  • FIG. 4 is a diagrammatic section showing a cathode arrangement wherein a plate of heavy metal is lowered into the body of the cathode.
  • FIG. 5 is a diagrammatic section illustrating the deviation of an ionic ray by means of a magnetic field.
  • FIG. 6 is a diagrammatic section showing the shooting of electrons by an electronic gun in an inclined direction upon the anode.
  • FIG. 7 is a diagrammatic section through a cathode arrangement wherein the electronic ray is deviated upon a curved path by 90.
  • FIG. 1 shows a vacuum casing l of the tube which contains the cathode device 2 and the anode device 3.
  • the cathode device 2 located at one end of the casing includes the outer casing 4, the mounting, namely, the actual cathode body 5, and the glow coils 6 and 7 which are actuated by lines 8, 9 and 10. Electrons leaving the coils 6 and 7 strike the rotary anode 11 which is connected by the axle 12 with the rotor 13.
  • a side shifting of the coils and such a shaping of the focus milling is provided, that there is a deviation of the electronic ray 14 upon the focal point 15 of the anode 11, as shown in FIG. 2.
  • the path 16 of ions shown by broken lines strikes the cathode body 5 at the location 17 outside of the coil 6.
  • the plate 19 consisting of molybdenum is arranged in a depression 20 so there is substantial space separation from the heating coil and the range of the electronic ray.
  • FIG. 5 corresponds to a substantial extent to that of FIG. 4.
  • a magnetic field 21 which is used to guide the ionic ray 22 upon the plate 23 consisting of tantalum which is arranged in the striking location.
  • the plate 23, as is also the case in the construction of FIG. 4, is located in a cover 23, shown by broken lines in FIG. 5 constituting a hollow space enclosed by metal walls, in which will be deposited the material given up by the plate 23.
  • FIG. 6 differs from the earlier described devices in that it does not require a special deviating device for the electronic ray 24, since this ray emerges with great acceleration from the electrode gun 25 and strikes the anode 26 in an inclined direction, so that particles emerging from the anode or ions released in space will not strike the cathode system.
  • the striking location of ions indicated by 25 is constructed in the same manner as in embodiments shown in other figures and is connected to or separately from the gun 25 in a manner which is not illustrated.
  • the shape of the cathode body 27 produces an electric field which devi ates the electronic ray 28 from the glow coil 29 by about to the anode 30. Ions leaving he focal point of the anode 29 pass through the hole 31 and stirke the plate 32 made of tungsten which is located in a separate hollow space 33 in a manner similar to that shown in FIGS. 4 and S.
  • the side walls of the space 33 constitute a tubular support 34 for the plate 32.
  • An X-ray tube comprising an anode body. a cathode body and at least one incandescent cathode coil located on said cathode body to project a cathode ray beam forming a focal spot on said anode body and located out of the area onto which said focal spot is projected in rectangular direction from its surface and which area is shaped to absorb ions, said area being fu rnished with a heat-conducting body of refractory material.
  • An X-ray tube according to claim 3 wherein the hole penetrates the cathode body totally and said area is located on a heat conducting body of refractory material suppoted on the rear of the cathode body.

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  • X-Ray Techniques (AREA)
  • Electron Sources, Ion Sources (AREA)
US443864A 1973-02-28 1974-02-19 X-ray tube Expired - Lifetime US3885179A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19732310061 DE2310061A1 (de) 1973-02-28 1973-02-28 Roentgenroehre

Publications (1)

Publication Number Publication Date
US3885179A true US3885179A (en) 1975-05-20

Family

ID=5873412

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Application Number Title Priority Date Filing Date
US443864A Expired - Lifetime US3885179A (en) 1973-02-28 1974-02-19 X-ray tube

Country Status (6)

Country Link
US (1) US3885179A (da)
JP (1) JPS502887A (da)
CH (1) CH563664A5 (da)
DE (1) DE2310061A1 (da)
FR (1) FR2219522B1 (da)
GB (1) GB1467487A (da)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5438605A (en) * 1992-01-06 1995-08-01 Picker International, Inc. Ring tube x-ray source with active vacuum pumping
US20060233308A1 (en) * 2005-04-19 2006-10-19 Rigaku Corporation X-ray tube
US20070140431A1 (en) * 2005-12-19 2007-06-21 Miller Robert S Shielded cathode assembly
US7352846B2 (en) 2005-10-21 2008-04-01 Rigaku Corporation Filament for X-ray tube and X-ray tube having the same
US20110038463A1 (en) * 2008-04-17 2011-02-17 Koninklijke Philips Electronics N.V. X-ray tube with passive ion collecting electrode

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2821597A1 (de) * 1978-05-17 1979-11-22 Siemens Ag Verwendung eines systems zur erzeugung eines elektronenflachstrahls mit rein elektrostatischer fokussierung in einer roentgenroehre
DE19700992C2 (de) * 1997-01-14 1999-10-07 Siemens Ag Röntgenröhre
DE102011003943A1 (de) * 2011-02-10 2012-08-16 Siemens Aktiengesellschaft Kathode und Röntgenröhre mit einer derartigen Kathode
US10242836B2 (en) 2012-03-16 2019-03-26 Nanox Imaging Plc Devices having an electron emitting structure
US9922793B2 (en) 2012-08-16 2018-03-20 Nanox Imaging Plc Image capture device
WO2015079393A1 (en) 2013-11-27 2015-06-04 Nanox Imaging Plc Electron emitting construct configured with ion bombardment resistant

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2691869A (en) * 1950-05-15 1954-10-19 Henry F Schmidt Unitary gated irrigation spile

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE538823C (de) * 1928-11-27 1931-11-17 Siemens Reiniger Veifa Ges Fue Gluehkathodenroentgenroehre
US2350269A (en) * 1942-06-15 1944-05-30 Gen Electric X Ray Corp X-ray tube
FR947581A (fr) * 1946-06-07 1949-07-06 Thomson Houston Comp Francaise Perfectionnements aux générateurs de rayons chi, et en particulier à leur cathode
US2671867A (en) * 1950-11-24 1954-03-09 Dunlee Corp Electrode structure for x-ray tubes

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2691869A (en) * 1950-05-15 1954-10-19 Henry F Schmidt Unitary gated irrigation spile

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5438605A (en) * 1992-01-06 1995-08-01 Picker International, Inc. Ring tube x-ray source with active vacuum pumping
US20060233308A1 (en) * 2005-04-19 2006-10-19 Rigaku Corporation X-ray tube
US7333592B2 (en) * 2005-04-19 2008-02-19 Rigaku Corp. X-ray tube
US7352846B2 (en) 2005-10-21 2008-04-01 Rigaku Corporation Filament for X-ray tube and X-ray tube having the same
US20070140431A1 (en) * 2005-12-19 2007-06-21 Miller Robert S Shielded cathode assembly
US7661445B2 (en) * 2005-12-19 2010-02-16 Varian Medical Systems, Inc. Shielded cathode assembly
US20110038463A1 (en) * 2008-04-17 2011-02-17 Koninklijke Philips Electronics N.V. X-ray tube with passive ion collecting electrode
US8351576B2 (en) 2008-04-17 2013-01-08 Koninklijke Philips Electronics N.V. X-ray tube with passive ion collecting electrode

Also Published As

Publication number Publication date
FR2219522B1 (da) 1978-01-06
DE2310061A1 (de) 1974-08-29
GB1467487A (en) 1977-03-16
CH563664A5 (da) 1975-06-30
JPS502887A (da) 1975-01-13
FR2219522A1 (da) 1974-09-20

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