US2499545A - Rotary x-ray tube - Google Patents

Rotary x-ray tube Download PDF

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Publication number
US2499545A
US2499545A US662133A US66213346A US2499545A US 2499545 A US2499545 A US 2499545A US 662133 A US662133 A US 662133A US 66213346 A US66213346 A US 66213346A US 2499545 A US2499545 A US 2499545A
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United States
Prior art keywords
cathode
anode
tube
rotation
axis
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
US662133A
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English (en)
Inventor
Tuuk Jacob Hermannus Van Der
Combee Bart
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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 US2499545A publication Critical patent/US2499545A/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
    • H01J35/24—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

Definitions

  • An X-ray tube of this type is known, for example, from German patent specification No. 574,865.
  • the cathode is arranged in the axis of rotation and, in order to deflect the electron beam, use is made of the' electric field between the anode and the cathode.
  • Bymean's of a stationary directing body which is fastened to the anode this field is given the structure required for this purpose.
  • the invention likewise relates to a rotary!- ray tube, wherein thecathode is located-in the axis of rotation.
  • the electrons are also moved to the anode in an oblique direction without the use of cross fields.
  • the stationary directingbody serving for this purpose is arranged in the proximity of the cathode.
  • This form of construction is better suitable for obtaining a sharply defined'focal spot than the well-known constructions and-consequently it favours the sharpnessof definition of the image; Besides; it has the-advantage that rapid secondary electrons, which in X-ray tubes may have allsorts of detrimental effects occur to amuch smaller extent.
  • the directing body may be electrically-connected to the incandescent'cathode. Under determined conditions, for example if it is desired that the focal spot should be movable in a radial direction, it is advantageous to keep the directing body insulated from the incandescent cathode and to provide it with a separate current supply wire, so that between the directing body and the cathode a potential difierence can be maintained.
  • the directing body may serve at the same time as a. collecting device which concentrates the electrons in the focal spot. It is mounted so as to be rotatable about the incandescent cathode and it has an oblique front face which exhibits an aperture for the passa e of the beam 2 of electrons which is located eccentrically with respect to the axis of rotation.
  • the electrons In the Well-known rotary X-ray tubes comprising a cathode which is also rotatable the electrons, only after having reached a considerable velocity, experience a noticeable force which forces them in a lateral direction, since the electric field in the proximity of the cathode still extends in an axial direction.
  • the electrons With the tube according to the invention, on the contrary, the electrons have already the desired direction when they enter the discharge path, owing to which the beam may beshorter and exhibits less disperson, which is beneficial to the sharp-'- wise the size and the'position of the focal spot would no longer be completely independent of the anode voltage.
  • the voltage on thedirecting body may also be negative with respect to the cathode and proportional to the anode voltage.
  • a device for controlling the suction anode voltage iscoupled-with the selector of the anode voltage in such a manner that, independently of the voltage chosen, the suction anode always has the same percentage of the anode voltage.
  • a directing body having a positive potential may be struck by electrons.
  • the disadvantage caused by the impact of electrons on the directing body is much less than with the tube wherein the directingbody is fastened-to the anode, since these electrons have a much higher speed and consequently generate X-rays and secondary electrons.
  • a directing body which comprises two diaphragms insulated from one another, of which the outer one is provided with a separate current supply wire and the inner one-is connected to the cathode or also has a separate current supply wire;
  • the outer diaphragm can be given in this case such a positive. "voltage proportional to the anode voltage that it aotsljas a suction anode.
  • an electron-optical lens which, in agreement with the object of the invention, concentrates the cathode rays on a very narrow focal spot.
  • the retracting efiect of the field in the proximity of the anode is slight owing to-the high speed the electrons have in the place.
  • This effect can, indeed, be suppressed by rotatably fastening to the anode a diaphragm whose front face is normal to the direction of the axis of the electron beam at the cathode.
  • the axis of the electric field in the acceleration space is a straight line and the space between the diaphragm and the anode is free from any field.
  • the diaphram exhibits a narrowed portion and in this place the directing body is mounted so as to be rotatable about the wall of the tube, consequently outside the vacuum.
  • This body should preferably have a rotation-symmetric shape and exhibit a longitudinal slit. It may have the shape of a funnel as well as that of a cylinder.
  • the slit causes disturbance of the radial symmetry of the electric field in the proximity of the cathode, which makes the electrons travel in an oblique direction.
  • Fig. 1 is a tube wherein the directing body has cathode potential.
  • Fig. 2 is a form of construction wherein the directing body consists of two parts.
  • Fig. '3 represents a tube wherein the directing body is located outside the vacuum.
  • Fig. 4 is an "axial projection of the directing body of the tube shown in Fig. 3.
  • the anode and the incandescent cathode are. denoted by I, 2 and 3 respectively.
  • the anode which is shown in section only in Fig.1, exhibits a cavity 4 for the purpose of cooling by means of a circulating liquid supplied through a "tube 5.
  • a directing body which, in the tubes according to Figs. 1 and 2, held in place by a magnetic yoke 6 when the X-ray tube rotatable about its axis 1 is set rotating.
  • the directing body is constituted by a collecting device 8 which is mounted on a metal cylinder 9 so as to be easily rotatable, said cylinder carrying the incandescent cathode. It is provided with ferromagnetic poles It in order to be immobilised magnetically with the aid of the yoke 6 when the tube is rotating. In order to give the desired direction to the lines of force of the electric field in the place where the electrons leave the body '8 the directing body exhibits an oblique front'face.
  • the directing body consists of two metal caps l3 and 14 which are insulated from one another, each of them having on the front side an oblique diaphragm. They are fastened to the pole system It by bolts l5, but rings I6 of insulating material ensure that only the cap I4 is electrically connected to the anchor l U.
  • the cap I3 is placed on a ball block l1 and thus it is connected with a current supply wire I8.
  • the anchor I0 bears on a ball block l9 and is thus connected with a current supply wire 20.
  • the wires I 8 and 20 are connected to bushes 2! and 22 which are secured to one another by means of an intermediate piece 23 of glass sealed thereto.
  • the blocks I1 and [9 are mounted on the bushes 21.
  • the bush 22 is clamped around a glass cylinder 24 which is sealed to the re-entrant portion 25 of the wall of the tube, which portion also carries a pinch 26.
  • Current supply wires 21 and 28 serve to'conduct the heating current of the cathode.
  • the wire 18 and therefore the cap 13 may be given a negative potential
  • the diaphragms of the caps l3 and II have each an ecc'entrically arranged aperture 28 and 30 respectively.
  • the beam of electrons passes through these apertures to the outside in the direction designated by 3
  • the wall I exhibits in the proximity of the incandescent cathode 3 a narrowed part "32, so that between the wall and the cylinder 33 whose edge surrounds the filament there is at this place only a narrow space.
  • a directing body 34 is rotatably arranged around the part 32. This can be kept completely stationary when the tube rotates about its axis 1, owing'to which vacillation of the focal spot, which cannot always be avoided when the direct ing body is magnetically immobilised, is excluded.
  • the directing body 34 has the shape of a funnel and exhibits awidelongitudinal slit 35 (Fig. 4). The consequence thereof is that with a negative potential of the directing body the electrons are deflected towards the slit and move in the direction indicated by 36 in the plane of symmetry of the body 34 to the anode target 12.
  • the potential or the locality of the directing body '34 it is possible to modify the locality of the focal spot. This is important, for example, with tubes designed for the testing of materials, in which case "it is required to generate X-rays of determined wavelengths. It may, in this case, be necessary to have at ones disposal anode targets of different materials, in order to be able to make a choice out of different spectra of the rays emitted. With a tube according to the invention these anode targets may be provided as concentric rings on the front face l2 of the anode. By regulating the potential -or. the,
  • the directing body 34 If the directing body 34 is given a positive potential with respect to the cathode, it attracts the beam of electrons and it causes the focal spot to be produced on the opposite side. It is consequently possible to cause the X-rays to emerge at will from the tube on two opposite sides.
  • An X-ray tube comprising a tubular evacuated envelope, cathode and anode electrodes mounted in said envelope and having a given axis for rotation thereabout with said envelope, said cathode having an emitting surface the diameter of which is small relative to the diameter of the area of electron impact on the anode, an electrostatic focussing element having a focussing axis forming an oblique angle with respect to the axis of rotation for directing a stream of electrons from the cathode at said anode, and means to fixedly position said focussing member to thereby permit relative rotation between said focussing member and said cathode during rotation of said tube.
  • An X-ray tube comprising a tubular evacu ated envelope, cathode and anode electrodes mounted within said envelope and having a given axis for rotation thereabout with said envelope, said cathode having an emitting surface the diameter of which is small relative to the diameter of the area of electron impact on the anode, an electrostatic focussing member interposed between the cathode and the anode having a iocussing axis forming an oblique angle with the said axis of rotation, means to apply a potential to said focussing member to focus a beam of electrons emitted by said cathode at said anode along said focussing axis, and means to fixedly position the focussing member to thereby permit relative rotation between the cathode and the focussing member during rotation of the tube.
  • An X-ray tube comprising a tubular evacuated envelope having a givenaxis for rotation thercabout, cathode and anode electrodes mounted within said envelope for rotation therewith about the axis of rotation, said cathode having an emitting surface the diameter of which is small relative to the diameter of the area of electron impact on the anode, a tubular body having a curved end portion enclosing one end thereof surrounding said cathode, said curved end portion having an aperture eccentrically located with respect to the axis of rotat on of said tubular evacuated envelope for providing an electron beam focussing axis forming an oblique angle with respect to the axis of rotation for directing a stream of electrons from the cathode at the anode, means for applying an energizing potential to said tubular body, bearing means interposed between said tubular body and said cathode to permit said tube to rotate relative to said tubular body, and means to fixedly position said tubular body to thereby permit relative rotation between said
  • a rotary Xray tube comprising a tubular evacuated envelope having a given axis for rotation thereabout, cathode and anode electrodes mounted within said envelope for rotation therewith about the axis of rotation, said cathode having an emitting surface the diameter of which is small relative to the diameter of the area of electron impact on the anode, an electrostatic focussing member comprising a plurality of diaphragm members electricallyinsulated from one another and positioned in proximity to said cathode electrode, said diaphragm members having aligned apertures eccentrically positioned with respect to the axis of rotation of said tube to provide an electron beam focussing axis forming an oblique angle with respect to the axis of rotation for directing a stream of electrons from the cathodeat the anode, bearing means interposed between said focussing member and said cathode to permit said tube to rotate relative to said focussing member, and means to fixedly position said focussing member within said envelope to thereby permit relative rotation between
  • a rotary X-ray tube comprising an evacuated tubular envelope having a given axis for rotation thereabout, cathode and anode electrodes mounted within said envelope for rotation therewith about the axis of rotation, said cathode having an emitting surface, the diameter of which is small relative to the diameter of the area of electron impact on the anode, an electrostatic focussing member comprising two diaphragm members spacedly positioned within said envelope and electrically insulated from each other, said diaphragm members positioned in proximity to said cathode and having aligned apertures eccentrically positioned with respect to the axis of rotation of said tube for providing an electron beam focussing axis forming an oblique angle with respect to the axis of rotation for directing a stream of electrons from the cathode at the anode, means for applying a negative potential to one of said diaphragm members, means for applying a positive potential to the other of said diaphragm members, bearing means interposed between said focuss
  • a rotary X-ray tube comprising an evacuated tubular envelope having a given axis for rotation thereabout, cathode and anode electrodes mounted within said envelope for rotation therewith about the axis of rotation, an electrostatic focussing member fixedly positioned external to said envelope and in proximity to said cathode for directing a stream of electrons emitted from said cathode at said anode in an oblique direction relative to said axis of rotation, and means for applying a negative potential to said focussing member.
  • a rotary X-ray tube comprising a tubular evacuated envelope having a portion of reduced cross-section and. having a given axis for rotation thereabout, cathode and anode electrodes mounted within said reduced portion for rotation with the envelope about the axis of rotation, a funnel-shaped member adapted to fit said reduced portion external to said envelope, and means for applying a negative potential to said funnelshaped member to thereby direct a stream of electrons emitted from said cathode at said anode in an oblique direction relative to said axis of rotation while said tube rotates relative to said funnel-shaped member.

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  • X-Ray Techniques (AREA)
US662133A 1943-12-31 1946-04-15 Rotary x-ray tube Expired - Lifetime US2499545A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL251524X 1943-12-31

Publications (1)

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US2499545A true US2499545A (en) 1950-03-07

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US (1) US2499545A (et)
BE (1) BE461891A (et)
CH (1) CH251524A (et)
FR (1) FR915221A (et)
GB (1) GB624030A (et)
NL (2) NL114571B (et)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2754349A (en) * 1951-03-28 1956-07-10 Leo C Werner Insulating spacers
DE2810628A1 (de) * 1977-03-14 1978-09-21 Neratoom Roentgenroehre
US4128781A (en) * 1976-02-25 1978-12-05 U.S. Philips Corporation X-ray tube
US4993055A (en) * 1988-11-23 1991-02-12 Imatron, Inc. Rotating X-ray tube with external bearings

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1203495A (en) * 1913-05-09 1916-10-31 Gen Electric Vacuum-tube.
US1219961A (en) * 1914-07-20 1917-03-20 Gen Electric Means for indicating electrical characteristics of alternating currents.
US1310061A (en) * 1917-04-13 1919-07-15 X-ray apparatus
AT127556B (de) * 1929-03-01 1932-04-11 Mueller C H F Ag Strichfokusröhre mit beweglicher Anode.
US2090582A (en) * 1934-02-09 1937-08-17 Gen Electric X Ray Corp X-ray tube
US2111412A (en) * 1928-12-08 1938-03-15 Gen Electric X-ray apparatus
US2119679A (en) * 1936-05-29 1938-06-07 Charles V Litton X-ray tube
DE671576C (de) * 1930-04-25 1939-02-13 Siemens Reiniger Werke Akt Ges Antriebsvorrichtung fuer drehbar gemachte Roentgenroehren
US2152363A (en) * 1934-12-13 1939-03-28 Firm Of Fernseh Ag Deflecting device for braun tubes
US2157718A (en) * 1935-02-26 1939-05-09 Mutscheller Arthur X-ray tube
US2240120A (en) * 1937-04-17 1941-04-29 Emi Ltd Electron device
US2336769A (en) * 1942-03-26 1943-12-14 Gen Electric X Ray Corp X-ray tube
US2361897A (en) * 1939-03-09 1944-10-31 Hartford Nat Bank & Trust Co Vacuum vessel

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1203495A (en) * 1913-05-09 1916-10-31 Gen Electric Vacuum-tube.
US1219961A (en) * 1914-07-20 1917-03-20 Gen Electric Means for indicating electrical characteristics of alternating currents.
US1310061A (en) * 1917-04-13 1919-07-15 X-ray apparatus
US2111412A (en) * 1928-12-08 1938-03-15 Gen Electric X-ray apparatus
AT127556B (de) * 1929-03-01 1932-04-11 Mueller C H F Ag Strichfokusröhre mit beweglicher Anode.
DE671576C (de) * 1930-04-25 1939-02-13 Siemens Reiniger Werke Akt Ges Antriebsvorrichtung fuer drehbar gemachte Roentgenroehren
US2090582A (en) * 1934-02-09 1937-08-17 Gen Electric X Ray Corp X-ray tube
US2152363A (en) * 1934-12-13 1939-03-28 Firm Of Fernseh Ag Deflecting device for braun tubes
US2157718A (en) * 1935-02-26 1939-05-09 Mutscheller Arthur X-ray tube
US2119679A (en) * 1936-05-29 1938-06-07 Charles V Litton X-ray tube
US2240120A (en) * 1937-04-17 1941-04-29 Emi Ltd Electron device
US2361897A (en) * 1939-03-09 1944-10-31 Hartford Nat Bank & Trust Co Vacuum vessel
US2336769A (en) * 1942-03-26 1943-12-14 Gen Electric X Ray Corp X-ray tube

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2754349A (en) * 1951-03-28 1956-07-10 Leo C Werner Insulating spacers
US4128781A (en) * 1976-02-25 1978-12-05 U.S. Philips Corporation X-ray tube
DE2810628A1 (de) * 1977-03-14 1978-09-21 Neratoom Roentgenroehre
US4161671A (en) * 1977-03-14 1979-07-17 B.V. Neratoom X-ray tube
US4993055A (en) * 1988-11-23 1991-02-12 Imatron, Inc. Rotating X-ray tube with external bearings

Also Published As

Publication number Publication date
CH251524A (de) 1947-10-31
FR915221A (fr) 1946-10-30
GB624030A (en) 1949-05-26
BE461891A (et)
NL114571B (et)
NL71102C (et)

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