40results about "X-ray tube cathode movement" patented technology

A structure to generate x-rays has a plurality of stationary and individually electrically addressable field emissive electron sources with a substrate composed of a field emissive material, such as carbon nanotubes. Electrically switching the field emissive electron sources at a predetermined frequency field emits electrons in a programmable sequence toward an incidence point on a target. The generated x-rays correspond in frequency and in position to that of the field emissive electron source. The large-area target and array or matrix of emitters can image objects from different positions and / or angles without moving the object or the structure and can produce a three dimensional image. The x-ray system is suitable for a variety of applications including industrial inspection / quality control, analytical instrumentation, security systems such as airport security inspection systems, and medical imaging, such as computed tomography.

An x-ray generating device includes a field emission cathode formed at least partially from a nanostructure-containing material having an emitted electron current density of at least 4 A / cm2. High energy conversion efficiency and compact design are achieved due to easy focusing of cold cathode emitted electrons and dramatic reduction of heating at the anode. In addition, by pulsing the field between the cathode and the gate or anode and focusing the electron beams at different anode materials, pulsed x-ray radiation with varying energy can be generated from a single device. Methods and apparatus for independent control of electron emission current and x-ray energy in x-ray tubes are also provided. The independent control can be accomplished by adjusting the distance between the cathode and anode. The independent control can also be accomplished by adjusting the temperature of the cathode. The independent control can also be accomplished by optical excitation of the cathode. The cathode can include field emissive materials such as carbon nanotubes.

An x-ray generating device includes a field emission cathode formed at least partially from a nanostructure-containing material having an emitted electron current density of at least 4 A / cm2. High energy conversion efficiency and compact design are achieved due to easy focusing of cold cathode emitted electrons and dramatic reduction of heating at the anode. In addition, by pulsing the field between the cathode and the gate or anode and focusing the electron beams at different anode materials, pulsed x-ray radiation with varying energy can be generated from a single device.

An x-ray generating device includes a field emission cathode formed at least partially from a nanostructure-containing material having an emitted electron current density of at least 4 A / cm2. High energy conversion efficiency and compact design are achieved due to easy focusing of cold cathode emitted electrons and dramatic reduction of heating at the anode. In addition, by pulsing the field between the cathode and the gate or anode and focusing the electron beams at different anode materials, pulsed x-ray radiation with varying energy can be generated from a single device. Methods and apparatus for independent control of electron emission current and x-ray energy in x-ray tubes are also provided. The independent control can be accomplished by adjusting the distance between the cathode and anode. The independent control can also be accomplished by adjusting the temperature of the cathode. The independent control can also be accomplished by optical excitation of the cathode. The cathode can include field emissive materials such as carbon nanotubes.

Electron emitter assemblies and methods for generating an electron beam are provided. The electron emitter assembly includes a laser (80) configured to emit a first beam (96) and a second beam (98). The electron emitter assembly also includes a mirror (92) configured to move to a first operative position to reflect a first light beam (96) to a first region (122) of the photocathode (116). The mirror (92) is also configured to move to a second operative position to reflect the second light beam (98) to a second region (140) of the photocathode (116). The photocathode (116) is arranged to emit a first beam of electrons (126) when the first beam (96) contacts the first area (122) and a second electron beam (98) when it contacts the second area (140). Electron Beam (144). The electron emitter assembly also includes an anode (118) positioned to receive the first and second electron beams (126, 144) from the photocathode (116).

An x-ray tube having a liquid lubricated bearing assembly and a liquid cooled anode target. The anode target and bearing assembly having increased lubrication and cooling to withstand higher power, higher temperature and higher load applications.

An x-ray radiator has an anode that emits x-rays, a cathode that thermionically emits electrons upon irradiation thereof by a laser beam, a voltage source for application of a high voltage between the anode and the cathode for acceleration of the emitted electrons toward the anode to form an electron beam, a vacuum housing, an insulator that is part of the vacuum housing and that separates the cathode from the anode, an arrangement for cooling components of the x-ray radiator, a deflection and arrangement that deflects the laser beam from a stationary source, that is arranged outside of the vacuum housing, to a spatially stationary laser focal spot on the cathode.

Tomosynthesis system with a rotating anode X-ray tube enabling a circular scan trajectory, wherein the X-ray tube 1 may be equipped with a large number of cathodes (21, 22) distributed around an anode. This allows to generate X-rays (41, 42) at focal spot positions (11, 12), for example evenly distributed on a for example circular line (14) on the surface (15) of an anode (10). The object (61) may be located on the (10) axis of rotation (6) of the anode at some distance to the source. For an examination, the object (61) may be exposed to X-ray beams (41, 42) generated successively on all focal spot positions (11, 12), wherein no movement of the X-ray tube 1 is necessary. The transmitted X-ray intensities may be measured by a flat panel detector (50) to achieve a reconstructed three-dimensional image data.

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.

A device for generation of x-ray radiation has one or more cold electron sources as a cathode and at least one x-ray target as an anode that are arranged in an evacuable housing. Upon application of an electrical voltage between cathode and anode, electrons emitted from the electron source are accelerated in an electron beam onto the x-ray target. A device for reduction of the proportion of positive ions in the region of the electron source is arranged between the electron source and the x-ray target in the housing. The device exhibits a long lifespan with good focusing capability and fast modulation capability of the electron beam.

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.

An x-ray radiator has an anode that emits x-rays, a cathode that thermionically emits electrons upon irradiation thereof by a laser beam, a voltage source for application of a high voltage between the anode and the cathode for acceleration of the emitted electrons toward the anode to form an electron beam, a vacuum housing, an insulator that is part of the vacuum housing and that separates the cathode from the anode, an arrangement for cooling components of the x-ray radiator, a deflection and arrangement that deflects the laser beam from a stationary source, that is arranged outside of the vacuum housing, to a spatially stationary laser focal spot on the cathode.

The present invention provides apparatus and method for providing a stabilized x-ray output from a field emission x-ray apparatus by monitoring the operating current and adjusting the gap between the anode and cathode to stabilize the output.

An electron emitter assembly and a method for generating an electron beam are provided. The electron emitter assembly includes a laser configured to emit a first light beam and a second light beam. The electron emitter assembly further includes a mirror configured to move to a first operational position to reflect the first light beam toward a first region of a photo-cathode. The mirror is further configured to move to a second operational position to reflect the second light beam toward a second region of the photo-cathode. The photo-cathode is configured to emit a first electron beam when the first light beam contacts the first region and to emit a second electron beam when the second light beam contacts the second region. The electron emitter assembly further includes an anode configured to receive the first and second electron beams from the photo-cathode.

Tomosynthesis system with a rotating anode X-ray tube enabling a circular scan trajectory, wherein the X-raytube 1 may be equipped witha large number ofcathodes (21, 22) distributed around an anode. This allows to generate X-rays (41, 42) at focal spot positions (11, 12), for example evenly distributed on a for example circular line (14) on the surface (15) of an anode (10). The object (61) may be located on the (10) axis of rotation (6) of the anode at some distance to the source. For an examination, the object (61) may be exposed to X-raybeams (41, 42) generated successively on all focal spot positions (11, 12), wherein no movement of the X-raytube 1 isnecessary. The transmitted X-rayintensities may be measured by a flat panel detector (50) to achieve a reconstructed three-dimensional image data.

An x-ray generating device includes a field emission cathode formed at least partially from a nanostructure (1110) containing material having an emitted electron current density of at least 4 A / cm2. High energy conversion efficiency and compact design (1100) are achieved due to easy focusing of cold cathode emitted electron between the cathode (1110) and the gate or anode (1130) and focusing the electron beams at different anode materials (1130), pulsed x-ray radiation with varying energy can be generated from a single device.

An x-ray radiator has an anode that emits x-rays when struck by electrons, a cathode that thermionically emits electrons upon irradiation thereof by a laser beam, a voltage source for application of a high voltage between the anode and the cathode for acceleration of the emitted electrons towards the anode to form an electron beam. A surface of the cathode that can be irradiated by the laser beam is at least partially roughened and / or doped and / or is formed of an intermetallic compound or vitreous carbon.

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.

The present invention provides apparatus and method for providing a stabilized x-ray output from a field emission x-ray apparatus by monitoring the operating current and adjusting the gap between the anode and cathode to stabilize the output.

An electron emitter assembly and a method for generating an electron beam are provided. The electron emitter assembly includes a laser configured to emit a first light beam and a second light beam. The electron emitter assembly further includes a mirror configured to move to a first operational position to reflect the first light beam toward a first region of a photo-cathode. The mirror is further configured to move to a second operational position to reflect the second light beam toward a second region of the photo-cathode. The photo-cathode is configured to emit a first electron beam when the first light beam contacts the first region and to emit a second electron beam when the second light beam contacts the second region. The electron emitter assembly further includes an anode configured to receive the first and second electron beams from the photo-cathode.

Emitter (3) and target (7) are arranged so as to face each other in vacuum chamber (1), and guard electrode (5) is provided at outer circumferential side of electron generating portion (31) of emitter (3). Emitter (3) is supported movably in both end directions of vacuum chamber (1) by emitter supporting unit (4) having movable body (40). To perform regeneration process of guard electrode (5), emitter is moved to no-discharge position by operating emitter supporting unit, and state in which field emission of electron generating portion (31) is suppressed is set, then by applying voltage across guard electrode (5), discharge is repeated. After regeneration process, by operating emitter supporting unit again, emitter is moved to discharge position, and state in which field emission of electron generating portion (31) is possible is set with movement of movable body (40) toward the other end side being restrained by movement restraining unit (6).

A bearing assembly for an x-ray tube is disclosed that includes a bearing race, a bearing ball positioned adjacent to the bearing race, and a combination coating deposited on one of the bearing race and the bearing ball. The combination coating includes titanium carbide and a solid lubricant.

An appliance for use in delivering x-ray radiation therapy internally at desired locations in a body is disclosed. The appliance may be inserted into the tissue to receive radiation and expanded to a desired shape, thereby providing a predetermined configuration to the tissue surrounding the appliance. The appliance can be configured to provide a spherical shape, for example, or an elliptical shape if desired.

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.

An X-ray tube comprises a vacuum vessel; a cathode and an anode fixedly disposed inside the vacuum vessel; and a rotary mechanism that rotates the vacuum vessel. The cathode is disposed on the circumference with the rotary shaft of the rotary mechanism as its center and includes a plurality of cathode parts that can individually be turned ON / OFF. The anode includes parts opposite to the plurality of cathode parts, respectively.

An emitter (3) and a target (7) are arranged so as to face each other in a vacuum chamber (1), and a guard electrode (5) is provided at an outer circumferential side of an electron generating portion (31) of the emitter (3). The emitter (3) is supported movably in both end directions of the vacuum chamber (1) by the emitter supporting unit (4) having a movable body (40). The emitter supporting unit (4) is operated by an operating unit (6) connected to the emitter supporting unit (4). By operating the emitter supporting unit (4) by the operating unit (6), a distance between the electron generating portion (31) of the emitter (3) and the target (7) is changed, and a position of the emitter (3) is fixed at an arbitrary distance, then field emission is performed with the position of the emitter (3) fixed.

An x-ray source in which monochromatic x-rays can be produced is provided. A method for producing X-rays and to the use of the x-ray source for x-raying bodies is also provided. A metallic film is arranged in a housing as a target which is bombarded with the electron beam. As a result, the metallic film is excited for emitting monochromatic x-rays, the relatively thin-walled target being modified such that the intended use for producing monochromatic x-rays is no longer possible. Therefore, advantageously, the production device can be pivoted for producing the electron beam as well as being able to wind the target on rollers.

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. In such an X-ray generator, an optical element 6 is arranged, which emits incident X-rays R1 and R2, in a taking-out route of the X-rays emitted from the anticathode parts 2, as diffracted X-rays R11 and R12, and also an adjustment mechanism 7 that aligns emitting directions of the diffracted X-rays with respect to the incident X-rays emitted from each anticathode part, to one direction, when the anticathode parts, against which the thermoelectrons from the cathode collide, are switched by moving the cathode.