US2496112A - X-ray tube - Google Patents

X-ray tube Download PDF

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Publication number
US2496112A
US2496112A US662962A US66296246A US2496112A US 2496112 A US2496112 A US 2496112A US 662962 A US662962 A US 662962A US 66296246 A US66296246 A US 66296246A US 2496112 A US2496112 A US 2496112A
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US
United States
Prior art keywords
anode
screen
cathode
aperture
cylindrical portion
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
US662962A
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English (en)
Inventor
Tuuk Jacob Harmannus Van Der
Smit Johannes Jan
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.)
Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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Filing date
Publication date
Application filed by Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
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Publication of US2496112A publication Critical patent/US2496112A/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
    • H01J35/26—Tubes wherein the point of impact of the cathode ray on the anode or anticathode is movable relative to the surface thereof by rotation of the anode or anticathode

Definitions

  • a hood In order to prevent the wall of X-ray tubes from being struck by electrons a hood is often placed on the anode, which hood exhibits opposite the cathode an aperture for the cathode rays and a lateral window through which the useful X-rays can emerge. By this cap secondary electrons are collected for the greater part thus preventing dangerous loads on the wall of the tube.
  • a hood When securing such a hood to a rotary anode it must have an aperture for the cathode rays whose diameter corresponds at least to that of the path covered by the outermost point of the focal spot. In this case the hood is too wide for collecting secondary electrons to a suflicient degree.
  • the invention concerns an X-ray tube having a rotary anode furnished with a screen which surrounds the front surface of the anode as a hood and exhibits opposite the cathode an aperture for the beam of primary electrons.
  • this screen does not follow the rotation of the anode so that the aperture does not transpose relatively to the cathode and need not exceed the section of the electron beam having to pass it. It extends completely beyond the axis of rotation and in this way the screen collects a much larger part of the electrons emitted by the heated part of the anode than if it would follow the rotation of the anode and would require a wide concentric aperture.
  • it collects metal particles disintegrating from the anode surface and breaks undesirable discharges.
  • the screen in the tube according to the invention must be placed at some distance from the front surface of the anode in order that electrons emitted from the focal spot on the anode may be checked as much as possible. Due to this the aperture for the beam of primary electrons cannot serve at the same time for the passage of the X-rays,
  • a stationary screen according to the invention still has other advantages than better checking the electrons and other particles from the focal spot.
  • the surface of the anode heated by electron-impact conserves a high temperature for some time so that, after it has left the beam of cathode rays, it is able to emit electrons.
  • the screen remains: at a comparatively low temperature so that it does not emit a considerable quantity of electrons. Its surface, where the lines of force end, is not attacked but remains smooth so that there is no risk of so-called cold emission.
  • the screen according to the invention acquires particular importance if it is extended to the rear and secured at the extremity, in contradistinction to the tube according to French pat. spec. 713,190 where it is attached at the middle, and more particularly with a good terminal contact, to the body from which is suspended the rotary part of the anode.
  • the rotary part is completely enclosed by the screen and then the latter is capable of absorbing the heat radiated by the rotor to the outside and of carrying it away to the supporting member, whence it can be transmitted to a cooler, such as the well-known highly upstanding ribs which fit with a small intermediate space in corresponding grooves of the rotor and serve to collect the radiated heat and to carry it off to the cooler.
  • a cooler such as the well-known highly upstanding ribs which fit with a small intermediate space in corresponding grooves of the rotor and serve to collect the radiated heat and to carry it off to the cooler.
  • the hood is provided at the inner side and the rotor at the outside
  • the outer surface of the screen may be made highly res flective. This is also advantageous from an electrical point of view, since there are no strong concentrations of the electric held at a smooth surface. Consequently secondary and coldemis sion is counteracted by making the surface smooth.
  • FIG. 1 is a longitudinal section of an X-ray tube
  • Fig. 2 being a cross-section of the same tube on the line II-II.
  • the wall of the tube consists of a metal middle :portion l and two glass: portions 2 and 3 sealed to. the. edges. thereof.
  • The. anode consists of. a rotarypartlha supporting body E'and a screen 6.
  • Thelatter. surrounds. the front surface of the ro tary Dartas av cap andexhibits opposite the cathode an. apcrtureB which lies entirel beyond the axis. of. rotation and permits the passage of the beam of' primary electrons.
  • the part of the screen where is provided? the aperturea is located at somedistance from the. conical front surface of. the rotor. Laterally of this front surface the.
  • a screen 6' exhibits a window 9. and opposite this window the metal part i has also a Window ill. These windows permit the passage of'the useful X-rays emitted by the tungsten anode mirror 5 E.
  • a sealing edge l2 which similarly to the part I may consist of chrome iron, and a cooling rod iii.
  • the glass part 2 exhibits a reentrant sealing tube M which is sealed to the rim l2.
  • the supporting body-5 contains two ball blocks [5 and IS in which is journall'ed a spindle H to which the rotor is'fixed-by means of a thin-walled metal tube l8.
  • the glass part 2' is surrounded by an electromagnetic system 191 by means of which a magnetic rotary fieldcan be produced by which the rotor iis actuated.
  • the metal part 1 maybe connected to a point of the electric feed system which has about equal potential differences in regard to the anode and thecathode and is usuall'y connected to earth.
  • the secondary and thermionically emitted electrons emitted by the strongly heated front surface of the rotor are collected for the greater part by the screen 6 and cannot involve an unduly strong current to the metal-part l. Inaddition they cannot form dangerous loads on the glass parts of the wall and on the metal part i if the latter is kept insulated. Owingto the screen a current between theanode and cathode in a wrong direction is not tube feared.
  • Thespace between the screen and the anodemirror is field-free for the greater part so-thatthe tendency of thetube. to emit electrons fromthe anode is low.
  • Thev screen. t extends to the, rear and is connected witha good terminal'contact to the outer wall of the supporting body 5.
  • the inner surfaceof thescreen opposite therotor and the outer surface-of the rotor-"5 opposite the screen are-s0 made asto readily absorb and radiate heat re spectively. They are preferably coated with a dull black layer.
  • the screen 6 readily takes up. heat from the rotor without contacting therewith. This heat is. carried. away to the supporting member b the screen 6 which preferably consists of copper.
  • the part ofthesupporting bodyprojectinginto the rotor absorbs the heat radiated by the. inner surface of the rotor. In the same way, therefore, the opposed surfaces of rotor and supporting body can also be made appropriate for the radiation and absorbtion of heat.
  • the supporting body 5 has a ring 20 of ferromagnetic material through which the magnetic rotary field isqlcompleted.
  • the lines of force of this field have to'penetrate through the stationary screen 6 and'may cause considerable Foucault currents therein which involves a decrease of the driving couple.
  • the screen opposite to the poles of the magnet' system l9 (this will usually have not more than three poles in order to attain as high a sp e of. rotation as possible) ma be furnished with apertures for the passage of the magnetic flux. These apertures are designated by 2
  • V7 hat we claim is:
  • An X-ray tube comprising a-cathod'eelec trode, a rotatable anode electrode; and a shield member comprising a cylindrical portion surrounding the anode and a disc-shaped portion closing the cylindrical portion interposed between the anode and cathode electrodes; said. cylindrical portion being fixedly'mounted" to a support member which rotatably supports the anode whereb the rotatableanode is completely onclosed. by the shield, said disc shaipe-d portion having :an aperture therein to permit electronsemitt'ed by said' cathode elect'rodeto impinge on said anode electrode and said cylindrical portion having an'aperture therein to permit. the passage of X-rays from saidanoda.
  • An XJ-ray tube comprising an evaouatedtubular envelope havin a metallic wall. portion, a cathode electrode within said: envelope, a. rotatable anode electrode within said envelope,v and a shield member comprising a cylindrical portion surrounding the anodeandia: disc shaped portion closing said cylindrical:portioninterposedbetween the cathode and anode electrodes; said cylindrical portion beingfixedly-mountedt to a suppor member which rotatably supports the anode whereby the rotatable anode.- is completely enclosed-by the shield; said-.disc-shapedportion having' an aperture thereinv to permit electrons emitted by said cathode electrode-to impinge on said anode electrode: and said cylindrical portion having an aperture therein. aligned with an aperture in said metal Walt-portion to-permit thepassage of X-rays.
  • An X-ra tube comprising-an evacuated tubular envelope having a metallicv wall portion, a cathode electrode within saidenvelope, at rotatable anode electrode within saidenvelope; and a shield member comprising a cylindrical portion surrounding theanode and: adisc-shaped portion closing the cylindrical portioninterposed'between the cathode and'anode electrodes, said cylindrical portion. being fixedly mounted-toasupport memher for rotatably supporting-.- the anode whereby the rotatable anode is completely enclosed by the shield, the external surfaceot which is smooth to prevent cold and. secondary emission.
  • said disc-shaped portion having; an aper-- ture therein tov permitelectronn emitted by said cathode electrode to impinge onsaid anode electrode. and. said cylindrical portion having an aperture therein aligned. with. an apertured pore ti-on in said metallic wall. portiomtopermit the passage of x rays.
  • An Y-ray tube comprising an evacuated tubular envelope having a metallic wall portion, a rotatable anode electrode within said envelope, a cathode electrode within said envelope, and a shield member comprising a cylindrical portion surrounding the anode and a disc-shaped portion closing the cylindrical portion interposed between the anode and cathode electrodes, said cylindrical portion being fixedly mounted to a support member for rotatably supporting the anode whereby the rotatable anode is completely enclosed within the shield member, the external surface of which is smooth to prevent secondary and cold emission therefrom, said disc-shaped portion having an aperture therein eccentricali disposed with respect to the axis of rotation of said anode to permit electrons emitted by said cathode electrode to impinge on said anode electrode and said cylindrical portion having an aperture therein aligned with an apertured portion in said metallic wall portion to permit the passage of X-rays.
  • An X-ray tube comprising an evacuated tubular envelope having a metallic wall portion, a rotatable anode electrode within said envelope,
  • a shield member comprising a cylindrical portion surrounding the anode and a disc-shaped portion closing the cylindrical portion interposed between the anode and cathode electrodes, said cylindrical portion being fixedly mounted to a support for rotatably supporting the anode electrode whereby the rotatable anode is completely enclosed within the shield member, said discshaped portion having an aperture therein eccentrically disposed with respect to the axis of r0- tation of said anode to permit electrons emitted by said cathode electrode to impinge on said anode electrode, said cylindrical portion having an aperture therein aligned with an apertured portion in said metallic wall portion to .permit the passage of X-rays and apertures therein to permit the passage of magnetic flux to cause said anode to rotate.
  • An X-ray tube comprising an evacuated tubular envelope having a metallic wall portion, a rotatable anode electrode within said envelope, a support member for rotatably supporting said anode, magnet means for impartin rotation to said anode electrode, a cathode electrode within said envelope, and a shield member comprising a cylindrical member surrounding the anode and a disc-shaped member closing the cylindrical member interposed between the anode and cathode electrodes, the cylindrical portion being fixedly mounted to said supporting member for said anode and in heat transfer relationship thereto for conducting heat away from said anode whereby said rotatable anode is completely enclosed within the shield member, said disc-shaped portion having an aperture therein eccentrically lobated with respect to the axis of rotation of said anode to permit electrons emitted by said cathode electrode to impinge on said anode electrode, said cylindrical portion having an aperture therein aligned with an apertured portion in said metallic wall portion to permit the passage of X-rays and apertures

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  • X-Ray Techniques (AREA)
US662962A 1941-11-20 1946-04-18 X-ray tube Expired - Lifetime US2496112A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL239103X 1941-11-20

Publications (1)

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US2496112A true US2496112A (en) 1950-01-31

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US662962A Expired - Lifetime US2496112A (en) 1941-11-20 1946-04-18 X-ray tube

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US (1) US2496112A (ro)
BE (1) BE448042A (ro)
CH (1) CH239103A (ro)
FR (1) FR887991A (ro)
GB (1) GB610447A (ro)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3018398A (en) * 1958-10-27 1962-01-23 Dunlee Corp X-ray generator
US3500097A (en) * 1967-03-06 1970-03-10 Dunlee Corp X-ray generator
US3855492A (en) * 1973-11-19 1974-12-17 Machlett Lab Inc Vibration reduced x-ray anode
US4188559A (en) * 1977-07-29 1980-02-12 Compagnie Generale De Radiologie Rotary anode X-ray tube
US6453011B1 (en) * 1999-12-02 2002-09-17 Dr. Franz Lohmann, Inh. Hermann Lohmann X-ray tube with rotating anode core

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1211092A (en) * 1915-06-05 1917-01-02 Gen Electric X-ray tube.
DE591005C (de) * 1928-08-31 1934-01-15 C H F Mueller Akt Ges Roentgenroehre mit oszillierender Anode
US1949347A (en) * 1924-06-04 1934-02-27 Philips Nv Electric discharge tube
US2075146A (en) * 1933-06-25 1937-03-30 Sergeeff Sergei Metallic roentgen tube with revolving anticathode
US2081789A (en) * 1932-05-30 1937-05-25 Philips Nv X-ray tube having a rotary anode
GB501253A (en) * 1937-08-02 1939-02-23 Philips Nv Improvements in or relating to x-ray tubes
US2205297A (en) * 1938-07-23 1940-06-18 Gen Electric X-ray tube
US2222549A (en) * 1937-12-23 1940-11-19 Hartford Nat Bank & Trust Co X-ray tube
US2229152A (en) * 1938-09-21 1941-01-21 Westinghouse Electric & Mfg Co Rotary anode X-ray tube
US2341483A (en) * 1942-08-19 1944-02-08 Hartford Nat Bank & Trust Co Getter for electron discharge tubes

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1211092A (en) * 1915-06-05 1917-01-02 Gen Electric X-ray tube.
US1949347A (en) * 1924-06-04 1934-02-27 Philips Nv Electric discharge tube
DE591005C (de) * 1928-08-31 1934-01-15 C H F Mueller Akt Ges Roentgenroehre mit oszillierender Anode
US2081789A (en) * 1932-05-30 1937-05-25 Philips Nv X-ray tube having a rotary anode
US2075146A (en) * 1933-06-25 1937-03-30 Sergeeff Sergei Metallic roentgen tube with revolving anticathode
GB501253A (en) * 1937-08-02 1939-02-23 Philips Nv Improvements in or relating to x-ray tubes
US2222549A (en) * 1937-12-23 1940-11-19 Hartford Nat Bank & Trust Co X-ray tube
US2205297A (en) * 1938-07-23 1940-06-18 Gen Electric X-ray tube
US2229152A (en) * 1938-09-21 1941-01-21 Westinghouse Electric & Mfg Co Rotary anode X-ray tube
US2341483A (en) * 1942-08-19 1944-02-08 Hartford Nat Bank & Trust Co Getter for electron discharge tubes

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3018398A (en) * 1958-10-27 1962-01-23 Dunlee Corp X-ray generator
US3500097A (en) * 1967-03-06 1970-03-10 Dunlee Corp X-ray generator
US3855492A (en) * 1973-11-19 1974-12-17 Machlett Lab Inc Vibration reduced x-ray anode
US4188559A (en) * 1977-07-29 1980-02-12 Compagnie Generale De Radiologie Rotary anode X-ray tube
US6453011B1 (en) * 1999-12-02 2002-09-17 Dr. Franz Lohmann, Inh. Hermann Lohmann X-ray tube with rotating anode core

Also Published As

Publication number Publication date
GB610447A (en) 1948-10-15
FR887991A (fr) 1943-11-29
CH239103A (de) 1945-09-15
BE448042A (ro)

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