With Movable Electrode Patents (Class 378/135)
  • Patent number: 11665806
    Abstract: The present disclosure relates to a downhole tool that includes a first photon flux detector disposed at a first radial position about a longitudinal axis of the downhole tool that measures a first signal indicative of an x-ray flux of the x-ray photons. The downhole tool also includes a second photon flux detector disposed at a second radial position about the longitudinal axis of the downhole tool that measures a second signal indicative of the x-ray flux of the x-ray photons. Further, the downhole tool includes a controller communicatively coupled to the first photon flux detector and the second photon flux detector that determines a condition associated with the electron beam based at least in part on a relative x-ray flux from the first photon flux detector and the second photon flux detector.
    Type: Grant
    Filed: December 20, 2019
    Date of Patent: May 30, 2023
    Assignee: SCHLUMBERGER TECHNOLOGY CORPORATION
    Inventors: Jani Reijonen, Vincent Ernst
  • Patent number: 11443913
    Abstract: An X-ray radiator and an X-ray assembly are disclosed. The X-ray radiator according to an embodiment has an evacuated X-ray tube housing, mounted to be rotatable about a rotation axis, the X-ray tube housing including an anode and an electron source. The anode is arranged within the X-ray tube housing non-rotatably relative to the X-ray tube housing and is configured to generate X-ray radiation via electrons impacting upon a focal spot of the anode, the electron source being mounted substantially stationary within the X-ray tube housing relative to the rotation axis. The electron source has a main emitter and at least one subsidiary emitter for emitting electrons. The electron emission of the main emitter and/or of the at least one subsidiary emitter is controllable such that a spatial movement of the focal spot due to a movement of the electron source is reduced.
    Type: Grant
    Filed: May 26, 2021
    Date of Patent: September 13, 2022
    Assignee: Siemens Healthcare GmbH
    Inventor: Anja Fritzler
  • Patent number: 11315750
    Abstract: An anode target comprises: a plurality of target structures, used for receiving an electron beam emitted by a cathode to generate a ray, the plurality of target structures being of three-dimensional structures having bevels; a copper cooling body, used for bearing the target structures and comprising an oxygen-free copper cooling body; a cooling oil tube, used for cooling the anode target; and a shielding layer, used for achieving a shielding effect and comprising a tungsten shielding layer. The anode target, the ray light source, the computed tomography scanning device, and the imaging method in the present application are able to enable all target spots on the anode target to be distributed on a straight line, imaging quality of a ray system is improved, and complexity of an imaging system is reduced.
    Type: Grant
    Filed: June 1, 2018
    Date of Patent: April 26, 2022
    Assignees: Nuctech Company Limited, TSINGHUA UNIVERSITY
    Inventors: Chengjun Tan, Wenhui Huang, Chuanxiang Tang, Qingxiu Jin, Dongsheng Zhang, Qun Luo, Donghai Liu, Luming Zhang, Peidong Wu
  • Patent number: 8983037
    Abstract: An X-ray tube with a rotatable anode for generating X-rays and an X-ray apparatus and a method for balancing the rotary anode of an X-ray tube include balancing of the rotary anode applicable to an anode mounted inside an X-ray tube. The rotatable anode includes an anode disc fixedly mounted to a rotatably driven support body, which is rotatably supported by a bearing arrangement. The anode includes at least one balancing cavity to adjust the center of gravity of the anode. The balancing cavity is partly filled with a balancing material being solid at operating temperature of the X-ray tube and liquid at a higher temperature. The balancing method includes determining an imbalance of the anode; heating liquefy balancing material; dislocating the balancing material inside the balancing cavity to compensate the imbalance; and cooling to solidify the balancing material.
    Type: Grant
    Filed: September 8, 2010
    Date of Patent: March 17, 2015
    Assignee: Koninklijke Philips N.V.
    Inventors: Rolf Karl Otto Behling, Christoph Bathe
  • Publication number: 20140314208
    Abstract: The present invention relates to balancing of a rotating anode. In order to provide a facilitated balancing of a rotating anode allowing balancing also in a state where the rotating anode disk is mounted inside an X-ray tube, an adjustment device (54) for balancing a rotating anode disk in an operating state is provided. The adjustment device comprises at least a first plurality (72) of balancing elements (74), wherein the balancing elements are attached to at least one circular ring structure (76), and wherein the balancing elements each comprise a balancing portion (80) mounted to the circular ring structure via a bending portion (82).
    Type: Application
    Filed: November 28, 2012
    Publication date: October 23, 2014
    Inventor: Marcus Walter Foellmer
  • Publication number: 20140270084
    Abstract: An x-ray transmission device includes two surfaces in frictional contact within a low fluid pressure environment provided by a housing substantially opaque to x-rays. Materials of the two surfaces are selected such that the frictional contact generates relative charging between the surfaces. The housing includes a window substantially transparent to x-rays, and an electron target, for example a metal, is on an interior surface of the window. The electron target faces the surface that is relatively negatively charged, such that electrons accelerated from that surface, or accelerated due to the negative charge of that surface strike the electron target to generate x-rays, which may be transmitted through the window.
    Type: Application
    Filed: March 15, 2013
    Publication date: September 18, 2014
    Inventor: Carlos G. Camara
  • Publication number: 20140126698
    Abstract: The present invention relates to the generation of multiple energy X-ray radiation. In order to provide multiple energy X-ray radiation with increased switching frequencies, a rotating anode (10) for an X-ray tube is provided with an anode body (12), a circular focal track (14), and an axis of rotation (16). The focal track is provided on the anode body and comprises at least one first focal track portion (18) and at least one second focal track portion (20). Transition portions (22) are provided between the at least one first and second focal track portions. The at least one first focal track portion is inclined towards an X-ray radiation projection direction (24) of the X-ray tube.
    Type: Application
    Filed: June 4, 2012
    Publication date: May 8, 2014
    Applicant: KONINKLIJKE PHILIPS N.V.
    Inventor: Rolf Karl Otto Behling
  • Publication number: 20130070903
    Abstract: The invention relates to an X-ray tube (12) with a rotatable anode (30) for generating X-rays and an X-ray apparatus (10) with such an X-ray tube and a method for balancing a rotary anode of an X-ray tube. In order to provide a balancing of the rotary anode applicable to an anode mounted inside an X-ray tube, an X-ray tube with a rotatable anode (30) for generating X-rays is provided, wherein the anode comprises an anode disc (32) fixedly mounted to a rotatably driven support body (44, 46), which support body is rotatably supported by a bearing arrangement (34). The anode comprises at least one balancing cavity (70) to adjust the center of gravity of the anode, which balancing cavity (70) is partly filled with a balancing material (72) being solid at operating temperature of the X-ray tube and liquid at a higher temperature.
    Type: Application
    Filed: September 8, 2010
    Publication date: March 21, 2013
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Rolf Karl Otto Behling, Christoph Bathe
  • Patent number: 8126117
    Abstract: A multi-beam x-ray system includes an x-ray source which emits x-rays and a housing with a first part and a second part. The second part is moveable relative to the first part and includes a plurality of optics of different performance characteristics. Each optic, through the movement of the second part relative to the first part, is positioned to a working position so that the optic receives the x-rays from the x-ray source and directs the x-rays with the desired performance attributes to a desired location.
    Type: Grant
    Filed: February 3, 2010
    Date of Patent: February 28, 2012
    Assignee: Rigaku Innovative Technologies, Inc.
    Inventors: Boris Verman, Michael Young, Licai Jiang
  • Publication number: 20110188636
    Abstract: A multi-beam x-ray system includes an x-ray source which emits x-rays and a housing with a first part and a second part. The second part is moveable relative to the first part and includes a plurality of optics of different performance characteristics. Each optic, through the movement of the second part relative to the first part, is positioned to a working position so that the optic receives the x-rays from the x-ray source and directs the x-rays with the desired performance attributes to a desired location.
    Type: Application
    Filed: February 3, 2010
    Publication date: August 4, 2011
    Applicant: Rigaku Innovative Technologies, Inc.
    Inventors: Boris Verman, Michael Young, Licai Jiang
  • Patent number: 7965818
    Abstract: Disclosed herein is an x-ray field emission apparatus, system and method, the apparatus having a hollow probe held at vacuum; a cathode enclosed within the probe, the cathode producing an electron stream when connected to a high negative potential; an anode enclosed within the probe and separated from the cathode by a gap, said the providing a target for the electron stream; and a shield assembly comprising a hollow shield electrode positioned within the probe and about the cathode.
    Type: Grant
    Filed: December 17, 2008
    Date of Patent: June 21, 2011
    Assignee: Minnesota Medical Physics LLC
    Inventors: Ali Jaafar, Victor I. Chornenky
  • Patent number: 7835501
    Abstract: According to an exemplary embodiment an x-ray tube comprises a cathode, rotable disc anode, and a focal spot modulating unit, wherein the cathode is adapted to emit an electron beam, and wherein the focal spot modulating unit is adapted to modulate the electron beam in such a way that an intensity distribution of the electron beam on a focal spot on the anode is asymmetric such that the intensity of the electron beam on the focal spot is higher at the front of the focal spot with respect to the rotation direction.
    Type: Grant
    Filed: October 9, 2007
    Date of Patent: November 16, 2010
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Stefan Hauttmann, Rainer Pietig, Jeroen Jan Lambertus Horikx
  • Patent number: 7778391
    Abstract: A field emission cathode has a field emitter and an extraction grid, and the field emitter and the extraction grid can be moved relative to one another. Such a field emission cathode is highly durable and exhibits a longer lifespan. An x-ray tube has a field emission cathode composed of a field emitter and an extraction grid that can be moved relative to one another. Such an x-ray tube is highly durable and exhibits a longer lifespan.
    Type: Grant
    Filed: June 4, 2009
    Date of Patent: August 17, 2010
    Assignee: Siemens Aktiengesellschaft
    Inventors: Jens Fuerst, Stefan Popescu, Georg Wittmann
  • Patent number: 7759663
    Abstract: A radiation source having self-shading electrodes is disclosed. Debris originating from the electrodes is reduced. The path from the electrodes to the EUV optics is blocked by part of the electrodes themselves (termed self-shading). This may significantly reduce the amount of electrode-generated debris.
    Type: Grant
    Filed: December 6, 2006
    Date of Patent: July 20, 2010
    Assignee: ASML Netherlands B.V.
    Inventors: Maarten Marinus Johannes Wilhelmus Van Herpen, Wouter Anthon Soer
  • Publication number: 20100008470
    Abstract: According to an exemplary embodiment an x-ray tube comprises a cathode, rotable disc anode, and a focal spot modulating unit, wherein the cathode is adapted to emit an electron beam, and wherein the focal spot modulating unit is adapted to modulate the electron beam in such a way that an intensity distribution of the electron beam on a focal spot on the anode is asymmetric such that the intensity of the electron beam on the focal spot is higher at the front of the focal spot with respect to the rotation direction.
    Type: Application
    Filed: October 9, 2007
    Publication date: January 14, 2010
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Stefan Hauttmann, Rainer Pietig, Jeroen Jan Lambertus Horikx
  • Patent number: 7518134
    Abstract: A radiation source is disclosed that includes an anode and a cathode that are configured and arranged to create a discharge in a substance in a discharge space between the anode and the cathode and to form a plasma so as to generate electromagnetic radiation, the anode and the cathode being rotatably mounted around an axis of rotation, the cathode being arranged to hold a liquid metal. The radiation source further includes an activation source arranged to direct an energy beam onto the liquid metal so as to vaporize part of the liquid metal and a liquid metal provider arranged to supply additional liquid metal so as to compensate for the vaporized part of the liquid metal.
    Type: Grant
    Filed: December 6, 2006
    Date of Patent: April 14, 2009
    Assignee: ASML Netherlands B.V.
    Inventors: Vladimir Vitalevitch Ivanov, Vadim Yevgenyevich Banine, Konstantin Nikolaevitch Koshelev, Vladimir Mihailovitch Krivtsun
  • Patent number: 7479646
    Abstract: An extreme ultraviolet source with wide-angle vapor containment and reflux is described. In the optical output directions radiating from the source plasma there is an array of tapered buffer gas heat pipes, with wick structures in the walls. In directions toward the insulators separating the discharge electrodes there are disc-shaped buffered gas heat pipes that prevent metal vapor from condensing on these insulators. A preferred electrode configuration has three electrode discs that operate in the star pinch mode. Another electrode configuration comprises two electrode discs and supports a pseudospark discharge. The star pinch variant of this source has efficiently generated 13.5 nm radiation with lithium vapor and helium buffer gas.
    Type: Grant
    Filed: December 11, 2006
    Date of Patent: January 20, 2009
    Assignee: PLEX LLC
    Inventor: Malcolm W. McGeoch
  • Publication number: 20080277599
    Abstract: A device constructed to generate radiation includes a liquid bath, and a pair of electrodes. At least a part of one of the electrodes is formed by a cable part moveable with respect to the liquid bath. The device also includes an actuator arranged to move the cable part from a liquid-adhering position to an ignition position, and an ignition source configured to trigger a discharge produced radiating plasma from the liquid adherent to the cable part, when the cable part is in the ignition position, by a discharge between the electrodes. The liquid-adhering position is a position for adhering a liquid from the bath to the part of the electrode.
    Type: Application
    Filed: May 9, 2007
    Publication date: November 13, 2008
    Applicant: ASML NETHERLANDS B.V.
    Inventors: Wouter Anthon Soer, Maarten Marinus Johannes Wilhelmus Van Herpen
  • Patent number: 7035377
    Abstract: To solve a difference in an emitting directions by switching the types of X-rays. An X-ray generator comprises: an anticathode unit 3 in which a plurality of anticathode parts 2 (2A and 2B) that emit X-rays by collision of thermoelectrons are disposed side by side; a cathode 4 for releasing the thermoelectrons toward the anticathode parts 2A and 2B on the anticathode unit 3; and a cathode moving mechanism that switches the anticathode parts, against which the thermoelectrons from the cathode 4 collide by moving the cathode 4 along the diction of aligning anticathode parts 2A and 2B.
    Type: Grant
    Filed: January 28, 2005
    Date of Patent: April 25, 2006
    Assignee: Bruker AXS K.K.
    Inventor: Chuji Katayama
  • Patent number: 6275567
    Abstract: The invention relates to a rotary-anode X-ray tube which includes a sleeve bearing which is composed of an inner and an outer bearing segment, the outer bearing segment including intermediate pieces and a holder on which the intermediate pieces bear so as to transfer the bearing forces. Suitable shaping of the external surfaces of the intermediate pieces and the inner surfaces of the holder which contact these outer surfaces ensures that the intermediate pieces become aligned with the bearing surfaces on the inner bearing segment. This strongly reduces the complexity of manufacture.
    Type: Grant
    Filed: September 10, 1998
    Date of Patent: August 14, 2001
    Assignee: U.S. Philips Corporation
    Inventor: Ulrich Hove
  • Patent number: 6164820
    Abstract: X-ray examination installation, particularly for computed tomography for mammography, has a rotating bulb x-ray tube with a cathode-side drive as its x-ray source, with the tube being oriented so that its anode faces toward the exposure side or actuation side of the system. The distance between the x-ray beam exit window of the tube, and the exposure side or actuation side of the system, thus is made small.
    Type: Grant
    Filed: May 6, 1999
    Date of Patent: December 26, 2000
    Assignee: Siemens Aktiengesellschaft
    Inventors: Erich Hell, Detlef Mattern, Peter Schardt
  • Patent number: 5581591
    Abstract: An x-ray tube includes an anode (A) and an envelope (C). A cathode assembly (B) which is supported in the envelope on a bearing (32) emits a beam of electrons which strike the anode forming a focal spot. The anode rotates (D) relative to the cathode such that focal spot follows a generally annular path along a beveled track (14). If the axis of the anode and the cathode assembly are screwed or offset, the focal spot path is not circular and wobbles. An adjustment assembly (60) adjusts the relative positions of the anode, the cathode and the envelope to adjust the anode and cathode assembly axes. The adjustment assembly also includes one or more electrodes (102, 108) which adjust the position of the focal spot. An angular position encoder (106) identifies an angular orientation of the anode. A control circuit (110) applies an electrostatic potential to the electrodes to move the focal spot such that it stays on a constant plane of the leveled anode surface.
    Type: Grant
    Filed: November 28, 1994
    Date of Patent: December 3, 1996
    Assignee: Picker International, Inc.
    Inventors: James E. Burke, Lester Miller, Salvatore Perno, Norman E. Wandke
  • Patent number: 5526396
    Abstract: An X-ray tube, comprising a cathode arrangement which includes an electron emitter connected to supporting pins which in turn are connected to the cathode structure via a respective fixing element. Particularly simple adjustment of the position of the filament is achieved in that the fixing elements are connected to the cathode structure in a first region and to the associated supporting pin in a second region which is remote from the first region, and that the fixing elements comprise a deformation zone between the first and the second region, deformation of said zone enabling adjustment of the position of the electron emitter relative to the cathode structure.
    Type: Grant
    Filed: July 8, 1994
    Date of Patent: June 11, 1996
    Assignee: U.S. Philips Corporation
    Inventor: Heinz-Jurgen Jacob
  • Patent number: 5475729
    Abstract: A toroidal x-ray tube (I) is supported and selectively positioned by a gantry (II). The x-ray tube includes a toroidal housing (A) in which a rotor (30) is rotatably mounted. One or more cathodes (C) are mounted on the rotor for generating an electron beam which strikes an anode (B) to generate a beam of x-rays which passes through a window (20) and strikes an annular ring of detectors (160). A grid bias control circuit (100) selectively applies a continuously adjustable bias to a grid (36) for regulating the electron current, hence the intensity of the x-ray beam. A scintillating optical fiber (110) extends around the exterior of the window. The scintillation optical fiber includes fluorescent dopant (116) which convert a very small fraction of the x-rays into optical light which is transmitted along the fibers to an opto-electric transducer (118). The opto-electric transducer is connected with the grid bias control circuit.
    Type: Grant
    Filed: April 8, 1994
    Date of Patent: December 12, 1995
    Assignee: Picker International, Inc.
    Inventors: Rodney A. Mattson, Theodore A. Resnick
  • Patent number: 5438605
    Abstract: A toroidal x-ray tube housing (A) is composed of multiple sections which are clamped together and sealed by elastomeric gaskets (128). An annular anode (B) is mounted to the housing with coolant passages (12, 14) extending thereadjacent. A rotor (30) is rotated within the toroidal housing by a motor (60). At least one cathode assembly (C) is mounted to the rotor adjacent the anode. The rotor is supported by magnetic bearings (40) whose active coils are separated from the vacuum region by a magnetic window (48). Alternately, a series of vanes (136, 138) are provided to divide the vacuum chamber into a high vacuum region (132) adjacent the cathode and anode and a low vacuum region (134) adjacent the motor (60) and bearings (40, 150, 152) for rotatably supporting the rotor within the housing. An active vacuum pump, preferably a ion pump (112) and a getter (114) are hermetically sealed into the vacuum region for maintaining the vacuum.
    Type: Grant
    Filed: December 6, 1993
    Date of Patent: August 1, 1995
    Assignee: Picker International, Inc.
    Inventors: James E. Burke, Lester Miller
  • Patent number: 5384820
    Abstract: A housing (A) which has a radiation transmissive window (52) defines a coolant oil reservoir (50). An x-ray tube (B) is mounted within the cooling oil reservoir. The x-ray tube includes a vacuum envelope having a cylindrical wall portion (10). A cylindrical sleeve (70) is mounted around the cylindrical wall (10) defining a narrow coolant oil gap (100). In one embodiment, a motor (16) rotates the vacuum envelope and an anode (14). The cylindrical sleeve (70) and the cylindrical rotating vacuum envelope wall portion (10) with the cooling oil film in the gap define a journal bearing which minimizes the horsepower requirements of the motor (16). A diaphragm (102) is expanded to reduce the thickness of the coolant oil film in the journal bearing gap. The cylindrical sleeve (70) is preferably constructed of a radiation blocking material such that the body of coolant oil (50) is shielded from x-rays (42).
    Type: Grant
    Filed: July 16, 1993
    Date of Patent: January 24, 1995
    Assignee: Picker International, Inc.
    Inventor: James E. Burke
  • Patent number: 5291538
    Abstract: An evacuated envelope (C) which is connected with an anode (A), has a cathode assembly (B) rotatably mounted inside. Magnets (44, 46) hold the cathode assembly stationary as the anode and envelope rotate. A ferrite core transformer (60) includes a ferrite core primary (66) stationarily mounted exterior to the envelope. A secondary (64) is mounted to the cathode assembly interior to the envelope. The secondary winding includes a ferrite core (70), a portion of which is surrounded by a ceramic, dielectric bobbin (76). The bobbin includes walls or ridges (78) which define a spiral groove (80) therearound in which an uninsulated electric wire (82) is received. The uninsulated electric wire is connected with a cathode filament (52). The primary winding has a ferrite core (90) that has about five times the cross section as the secondary ferrite core to compensate for a low, about 20%, coupling efficiency between the primary and secondary windings.
    Type: Grant
    Filed: June 3, 1993
    Date of Patent: March 1, 1994
    Assignee: Picker International. Inc.
    Inventors: James E. Burke, Lester Miller, Salvatore G. Perno
  • Patent number: 5274690
    Abstract: An x-ray tube includes an anode (A) and envelope (C) which are rotated (D) at a relatively high rate of speed. A cathode assembly (B) is supported in the envelope on a bearing (32). In order to hold the cathode assembly stationary, a magnetic susceptor (40) having periodic projections (44) is disposed with the projections closely adjacent an outer peripheral wall (20) of the envelope. A plurality of permanent magnets (52) are mounted on a stationary keeper (50), each magnet adjacent one of the susceptor projections. Preferably, the magnets have alternating polarity such that magnetic flux lines (54) flow between adjacent magnets through the magnetic susceptor.
    Type: Grant
    Filed: December 9, 1992
    Date of Patent: December 28, 1993
    Assignee: Picker International, Inc.
    Inventors: James E. Burke, Lester Miller, Salvatore G. Perno
  • Patent number: 5268955
    Abstract: A toroidal x-ray tube housing (A) has an evacuated interior. An annular anode (B) is connected with the housing closely adjacent the window such that a cooling fluid passage (12) is defined in intimate thermal communication with the anode. A cathode assembly (32) is mounted within the evacuated housing or an annular ring (30) that rotates an electron beam (22) around the large diameter annular anode. In the embodiment of FIGS. 1 and 2, the annular ring is magnetically levitated (40) and rotated by a motor (50). A collimator (62) and filter (64) are rotated with the cathode assembly closely adjacent an electron emitter or cathode cup (32) such that the generated x-rays are collimated and filtered within the x-ray tube. Preferably, a plurality of cathode cups (120) are provided, whose operation is selected by a series of magnetically controlled switches (76). The cathode cup is insulated (106) from the annular ring and isolated by a transformer (104, 112) from the filament current control switches.
    Type: Grant
    Filed: April 8, 1992
    Date of Patent: December 7, 1993
    Assignee: Picker International, Inc.
    Inventors: James E. Burke, Lester Miller
  • Patent number: 5241577
    Abstract: An anode (A) closes one end of an evacuated envelope (C) and a cathode end plate (22) closes the other. A cathode assembly (B) is mounted on a bearing (40) in the evacuated envelope such that the envelope and cathode can undergo relative rotation. A motor (38) rotates the anode and envelope while a pair of magnets (44, 46) hold the cathode assembly stationary. Bearing (40) functions as a current path from a current source (72) to the primary windings of a transformer (58). Another bearing (94) provides a return current path from the transformer to the current source. The secondary windings of the transformer are connected with a cathode filament (52). The transformer enables a relatively low ampere current to pass through the bearings to limit cathodic damage to the bearings, yet provides sufficient amperage to the filament to cause thermionic emission.
    Type: Grant
    Filed: January 6, 1992
    Date of Patent: August 31, 1993
    Assignee: Picker International, Inc.
    Inventors: James E. Burke, Salvatore G. Perno
  • Patent number: 5200985
    Abstract: A cathode assembly (B) including cathode filaments (52, 54) remain stationary in the interior of a rotating evacuated envelope (C). The cathode filaments generate a beam of electrons (12) which strike an annular anode surface (10) that rotates with the envelope to generate a beam of x-rays (14). Electrical power from an AC electrical source (62) is conveyed across a circularly cylindrical peripheral side wall (20) of the envelope by pairs of concentric capacitive ring members (64, 70); (66, 72). One of the cathode filaments is selected either with (i) reed switches (82, 84), (ii) by bringing a selected one of the filaments and the capacitor rings into resonance at the frequency of the AC electrical source with a switch (86) and inductance (88a, 88b), or (iii) with a third pair of annular capacitive members (100, 102).
    Type: Grant
    Filed: January 6, 1992
    Date of Patent: April 6, 1993
    Assignee: Picker International, Inc.
    Inventor: Lester Miller
  • Patent number: 5179583
    Abstract: An X-ray tube for a CT apparatus comprises a ring-shaped vacuum tube containing a fixed cathode having a thermion emitting surface, a ring-shaped fixed anode, and a ring-shaped rotatable cathode interposed between the fixed cathode and fixed anode. The rotatable cathode defines a thermion receiving surface opposed to the thermion emitting surface, and a thermion emitting portion opposed to the fixed anode. Thermions are emitted from the thermion emitting portion toward the fixed anode while the rotatable cathode is suspended to non-contact state and rotated at high speed. With the thermions being accelerated and colliding on the fixed anode, an X-ray is generated toward the center of the vacuum tube. The X-ray generating position moves at high speed along a circumferential surface of the fixed anode with rotation of the rotatable cathode.
    Type: Grant
    Filed: April 30, 1991
    Date of Patent: January 12, 1993
    Assignee: Shimadzu Corporation
    Inventor: Shiro Oikawa
  • Patent number: 4679219
    Abstract: An X-ray tube is disclosed, which comprises an evacuated envelope having a cathode assembly and an anode assembly provided at the opposite ends of the envelope such that they face each other. The cathode assembly includes a spiral filament for generating an electron beam with a beam axis. One of the terminal ends of the spiral filament is located in the proximity of the center thereof. The anode assembly includes a conical target with a tip corresponding to the beam axis, for radiating X-rays in all directions. When a current flows with the filament of the X-ray tube, the temperature of the filament is reduced for a central portion thereof to reduce the density of electrons emitted from the central portion, thus preventing overheating of the tip of the conical target.
    Type: Grant
    Filed: June 12, 1985
    Date of Patent: July 7, 1987
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Hidemichi Ozaki
  • Patent number: 4675891
    Abstract: The invention relates to an X-ray apparatus with focus position control, the focus being formed on the anode of an X-ray tube with magnetic bearings. The X-ray apparatus comprises a focus position sensing device cooperating with electronic means associated with the magnetic bearings, in order to control the position of the focus by displacing a rotor under the action of the magnetic bearings.
    Type: Grant
    Filed: June 25, 1985
    Date of Patent: June 23, 1987
    Assignee: Thomson-CGR
    Inventors: Andre Plessis, Jacques Leguen
  • Patent number: 4669102
    Abstract: A method and a device for operating and focusing a tomographic x-ray unit using an electron beam and embodying at least one electron gun (1), an anode (2) at which the gun is aimed as well as the x-ray detectors (5) needed to produce a tomographic photograph. In order to construct a device with a sufficiently short exposure time and capable of taking tomographic photographs of fast-moving objects, it is particularly characteristic of this invention that an electron beam (8) emitted by an electron gun (1) is roughly deflected at a hole (4) in the focusing plane (3) which, by means of focusing field lines, draws the electrons into the hole, focuses and accelerates the electron beam which strikes the surface of the anode (2), generating an x-ray source, and that the focusing hole (4) is moved in regard to the anode (2) to generate a series of x-ray sources needed to produce a "layerwise" tomographic photograph of the object under examination.
    Type: Grant
    Filed: April 18, 1984
    Date of Patent: May 26, 1987
    Assignee: Puumalaisen Tutkimuslaitos Oy
    Inventor: Pertti Puumalainen
  • Patent number: 4563769
    Abstract: In an X-ray generator device a target member emitting X-rays by electron bombardment is arranged in a rod-shaped tubular probe and is provided with a conically tapering front part facing a comparatively narrow aperture in a controlling electron beam diaphragm for the purpose of forming a substantially punctiform radiation source. The position of the target member is adjusted by securing the rod-shaped target member at a part of its length reckoned from its opposite, rearmost end in a central bore of an oblong cylindrical target carrier positioned coaxially in the probe, said target carrier being only at its foremost end connected with the wall of the probe, thereby allowing fine adjustment of the target member with respect to said aperture by displacement of said opposite end of the target carrier in a radial plane in the probe, e.g. by means of wedge means formed as adjusting screws in the annular channel between the target carrier and the inner wall of the probe.
    Type: Grant
    Filed: December 21, 1982
    Date of Patent: January 7, 1986
    Assignee: Andrex Radiation Products A/S
    Inventor: Jens U. Madsen
  • Patent number: 4357555
    Abstract: An X-ray tube having a rotary anode which is supported by a bearing system comprising an axial magnetic bearing and at least one radial sleeve bearing. In operation, mutually cooperating metal (e.g. W or Mo) supporting faces of the sleeve bearing are separated by a liquid layer wetting the supporting faces. The liquid layer consists of a metal or a metal alloy, such as Ga or a Ga alloy, whose vapor pressure at 300.degree. C. is below 10.sup.-5 N/m.sup.2, and which does not attack the supporting faces to any substantial extent. The tube has a long life, produces little noise during operation, and is of relatively simple construction.
    Type: Grant
    Filed: May 8, 1980
    Date of Patent: November 2, 1982
    Assignee: U.S. Philips Corporation
    Inventors: Jan Gerkema, Evert M. H. Kamerbeek