US3714487A - X-ray tube having external means to align electrodes - Google Patents

X-ray tube having external means to align electrodes Download PDF

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Publication number
US3714487A
US3714487A US00117436A US3714487DA US3714487A US 3714487 A US3714487 A US 3714487A US 00117436 A US00117436 A US 00117436A US 3714487D A US3714487D A US 3714487DA US 3714487 A US3714487 A US 3714487A
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US
United States
Prior art keywords
sleeve
envelope
electrode
ray tube
electrodes
Prior art date
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
US00117436A
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English (en)
Inventor
H Jacob
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
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US Philips Corp
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Filing date
Publication date
Priority claimed from DE19702014937 external-priority patent/DE2014937C3/de
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3714487A publication Critical patent/US3714487A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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

Definitions

  • the invention relates to an X-ray tube whose electrodes (anode and cathode) are connected with the tube bulb in a vacuum-tight manner.
  • the bulb of known X-ray tubes usually consists of glass.
  • the anode is then soldered to a ring consisting of an alloy having the same thermal expansion coefficient as glass and sealed-to the bulb by glass.
  • the cathode is usually mounted on a glass pinch. After assembly the ends of the glass bulb and of the pinch are heated, bent over towards each other and-fused together. As a matter of course this method of assembling does not permit an accurate alignment of the anode and the cathode.
  • this construction does not always provide useful results.
  • the required relative positionsof'cathode and anode have to be accurate within a tolerance of a fraction of a millimeter. Such an accuracy cannot be attained in the known structure.
  • local fusion of the target plate may occur during the first hours of operation and particularly during the running-in period, in which the power of the X-ray tube is gradually raised from an appropriate value to the nominal power. Said fusion is caused by residual gas released from the tube parts upon being heated, said gas being ionized by the voltage applied to the tube and affecting the field so that the electrons, which normally impinge upon a surface of 2 X 3 mms, are focused at one point. At this point temperatures are produced which result in fusion of the electron target plate.
  • the invention has for its object to avoid these disadvantages. According to the invention this is achieved by connecting at least one electrode, preferably the cathode, with the tube bulb by way of a deformable intermediate member, the deformation of which results in a variation of the place of the focal spot.
  • the cathode In general it is efficient to connect only the cathode through such an intermediate piece with the bulb of the tube, because the cathode has a smaller weight than the anode.
  • the deformable intermediate piece permits of shifting the cathode and the anode relatively to each other so that, for example, with conical anode X-ray tubes the focal spot is accurately concentrical to the tip of the conical anode. in X-ray tubes whose target plate is sealed at one place the focal spot can be located on an undamaged surface portion.
  • FIG. 1 is a cross sectional view and P10. 2 a plan view of an X-ray tube embodying the invention and a device for varying thefocal spot location is shown. 7
  • connection of the anode 2 with the glass bulb l is not shown in the drawing: it may i be made in known manner by means of a ring of an alloy (tradename Vacon) having the same heat expansion coefficient as glass, one end of said ring being soldered to the anode and the other end being sealed to the glass bulb. in this way a rigid connection is established between the anode and the glass bulb.
  • a ring of an alloy (tradename Vacon) having the same heat expansion coefficient as glass
  • the cathode 3 comprises a filament 4 and a cathode pot 5 acting upon the electron path, which elements are secured to a plate 6, to which is furthermore secured an external protecting cylinder 7 of nickel.
  • the plate 6 is held by a metal sleeve 8, which is slipped on a further metal sleeve 9, to which it is secured.
  • the metal sleeve 9, whose end projecting into the glass bulb is hermetically closed by a glass passage, is secured to a disc 11, from which it protrudes over about 10 mms.
  • the disc 11 is secured to a ring '12 of Vacon, which is sealed in turn to the giass bulb 1.
  • the connection between the parts 5 to 9 and 11, 12 of the cathode may be established in known manner by hard solder or by welding.
  • the positions of the filament 4 and of the cathode pot 5 and hence also the position of the focal spot can be varied in this construction by displacing the sleeves 8 and 9 relatively to the disc 1 1, without an appreciable load on the metal-glass connection between the ring 12 and the glass bulb l.
  • the drawing shows a suitable device for adjusting or displacing the focal spot. It comprises a bipartite sleeve 13, which is slipped onto the ring 12 and is tightened by means of screws 20 (FIG. 2).
  • the lower end of the sleeve 13 has a guide in which a flange l4'can be turned over at least 360 about the axis of the tube.
  • the flange 14 has a tapped hole for receiving a screw 15, the inner end of which is provided with'a suitably shaped extension 16, which engages a tube 17 of hard steel having a thick wall and being slipped into the cathode sleeve 9.
  • the cathode 3, that is to say the filament 4 and the cathode pot, are thus displaced in'the direction of the screw 15, the extent of the deflection being determined by the pressure exerted by the screw 15 on the tube -17.
  • the adjustment of the focal spot to the tip of the anode cone may be carried out as follows:
  • the X-ray tube driven by nominal voltage and an appropriate cur- 'rent is arranged on a .radiation density container provided with a radiation measuring chamber and turned by means of a motor once over 360 about its own axis.
  • the radiation intensity can be automatically registered in dependence upon the relative angles of rotation.
  • the screw 15 with the flange 14 is moved into the position corresponding to the minimum indication and tightened.
  • the connection between the disc 11 and the sleeve 9 is plastically deformed to an extent such that a repeated measurement exhibits a more uniform distribution of the dosage (deviation smaller than 10 percent) along the periphery.
  • An X-ray tube comprising an evacuated envelope, a plurality of electrodes within said envelope, a deformable rigid intermediate member connecting one of said electrodes to said envelope in a vacuum tight manner for laterally moving one electrode relative to the other, said deformable rigid intermediate member comprising a sleeve supporting the one electrode, a cup-shaped part secured to said envelope and sleeve, said cup-shaped part having a disc-shaped bottom arranged at right angles to said sleeve, and a plate having at least three relatively shifted tapped holes for receiving screws to be tightened against said disc-shaped bottom, and means for deforming said intermediate member to vary the position of the one electrode.

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  • X-Ray Techniques (AREA)
US00117436A 1970-03-26 1971-02-22 X-ray tube having external means to align electrodes Expired - Lifetime US3714487A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19702014937 DE2014937C3 (de) 1970-03-26 Röntgenröhre mit Justiervorrichtung, die eine Kippung einer eine der Röhren-Elektroden tragenden Hülse relativ zur Röhrenkolben-Achse ermöglicht

Publications (1)

Publication Number Publication Date
US3714487A true US3714487A (en) 1973-01-30

Family

ID=5766521

Family Applications (1)

Application Number Title Priority Date Filing Date
US00117436A Expired - Lifetime US3714487A (en) 1970-03-26 1971-02-22 X-ray tube having external means to align electrodes

Country Status (4)

Country Link
US (1) US3714487A (cg-RX-API-DMAC7.html)
CH (1) CH520400A (cg-RX-API-DMAC7.html)
FR (1) FR2085011A5 (cg-RX-API-DMAC7.html)
GB (1) GB1289949A (cg-RX-API-DMAC7.html)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4128781A (en) * 1976-02-25 1978-12-05 U.S. Philips Corporation X-ray tube
EP0083198A1 (en) * 1981-12-29 1983-07-06 Andrex Radiation Products A/S An X-ray generator device
US4679219A (en) * 1984-06-15 1987-07-07 Kabushiki Kaisha Toshiba X-ray tube
US5581591A (en) * 1992-01-06 1996-12-03 Picker International, Inc. Focal spot motion control for rotating housing and anode/stationary cathode X-ray tubes
US20140239799A1 (en) * 2013-02-25 2014-08-28 Siemens Aktiengesellschaft Flat emitter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2058105A (en) * 1928-03-31 1936-10-20 Pohl Ernst Rontgen tube
US2130020A (en) * 1934-03-13 1938-09-13 Harry B Mceuen Cathode filament control for x-ray tubes
US2926270A (en) * 1957-12-30 1960-02-23 Gen Electric Rotating anode x-ray tube
US3303372A (en) * 1964-08-20 1967-02-07 Dunlee Corp X-ray generator with a knife edged cold cathode emitter
US3398307A (en) * 1962-05-28 1968-08-20 Varian Associates Electron beam X-ray generator with rotatable target movable along axis of rotation

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2058105A (en) * 1928-03-31 1936-10-20 Pohl Ernst Rontgen tube
US2130020A (en) * 1934-03-13 1938-09-13 Harry B Mceuen Cathode filament control for x-ray tubes
US2926270A (en) * 1957-12-30 1960-02-23 Gen Electric Rotating anode x-ray tube
US3398307A (en) * 1962-05-28 1968-08-20 Varian Associates Electron beam X-ray generator with rotatable target movable along axis of rotation
US3303372A (en) * 1964-08-20 1967-02-07 Dunlee Corp X-ray generator with a knife edged cold cathode emitter

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4128781A (en) * 1976-02-25 1978-12-05 U.S. Philips Corporation X-ray tube
EP0083198A1 (en) * 1981-12-29 1983-07-06 Andrex Radiation Products A/S An X-ray generator device
US4563769A (en) * 1981-12-29 1986-01-07 Andrex Radiation Products A/S X-Ray generator device
US4679219A (en) * 1984-06-15 1987-07-07 Kabushiki Kaisha Toshiba X-ray tube
EP0168641A3 (en) * 1984-06-15 1987-10-28 Kabushiki Kaisha Toshiba X-ray tube
US5581591A (en) * 1992-01-06 1996-12-03 Picker International, Inc. Focal spot motion control for rotating housing and anode/stationary cathode X-ray tubes
EP0715333B1 (en) * 1994-11-28 2001-05-30 Marconi Medical Systems, Inc. X-ray tube assemblies
EP1087419A3 (en) * 1994-11-28 2004-01-07 Koninklijke Philips Electronics N.V. X-ray tube assemblies
US20140239799A1 (en) * 2013-02-25 2014-08-28 Siemens Aktiengesellschaft Flat emitter

Also Published As

Publication number Publication date
DE2014937B2 (de) 1972-02-17
CH520400A (de) 1972-03-15
GB1289949A (cg-RX-API-DMAC7.html) 1972-09-20
DE2014937A1 (de) 1971-11-04
FR2085011A5 (cg-RX-API-DMAC7.html) 1971-12-17

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