250results about "X-ray tube multi-cathode assembly" 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 at least one field-emission cold cathode having a substrate and incorporating nanostructure-containing material including carbon nanotubes. The device further includes at least one anode target. Associated methods are also described.

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.

A micro-miniature x-ray apparatus comprises: a first chip subassembly including a source of x-rays including both Bremsstrahlung photons and characteristic x-rays; a second chip subassembly including a filter for transmitting the characteristic x-rays and blocking the Bremsstrahlung photons; a third chip subassembly including a movable element for focusing or collimating the transmitted characteristic x-rays into a beam and means for controlling the position of the focusing element. In one embodiment, the controlling means include a micro-electromechanical system (MEMS). In another embodiment, the position of the movable element determines how the x-ray beam is steered to the focal area. In still another embodiment, the x-ray source includes a field emitter electron source and a target responsive to the electrons for generating x-rays. In this case, the x-ray beam is also steered by selectively energizing the anode segments. In yet another embodiment, the movable element includes a Fresnel zone plate; in still another embodiment it includes an array of poly-capillaries. Advantageously, our x-ray source, including its focusing, collimating and steering components, can be fabricated small enough to be mounted at the end of a catheter. In addition, in some embodiments it can also fabricated sufficiently inexpensively to be disposable after each use.

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.

A dual filament x-ray tube assembly (16) includes an evacuated envelope (52) having an anode (54) disposed at a first end of the evacuated envelope (52) and a cathode assembly (62) disposed at a second end of the evacuated envelope (52). The cathode assembly includes a variable-length filament assembly (72, 74; 100) which emits electron beams for impingement on the anode (54) at focal spots having varying lengths. The cathode assembly (62) further includes a cathode cup (64, 66, 68; 110, 112) which is subdivided into a plurality of electrically insulated deflection electrodes (64, 66, 68; 110, 112). A filament select circuit (80) selectively and individually heats a portion of the variable-length filament assembly (72, 74). Electron beams emitted from the filament assembly (72, 74) are electrostatically focused and controlled by applying potentials to different ones of the deflection electrodes (64, 66, 68; 110, 112). The x-ray tube assembly (16) provides longer focal spots for thick-slice scanning applications and shorter focal spots for thin-slice scanning applications along with the benefit of electrostatic focusing and control.

A multi X-ray generating apparatus which has a plurality of electron sources arranged two-dimensionally and targets arranged at positions opposite to the electron sources includes a multi electron source which includes a plurality of electron sources and outputs electrons from driven electron sources by selectively driving a plurality of electron sources in accordance with supplied driving signals, and a target unit which includes a plurality of targets which generate X-rays in accordance with irradiation of electrons output from the multi electron source and outputs X-rays with different radiation qualities in accordance with the generation locations of X-rays. The generation locations and radiation qualities of X-rays from the target unit are controlled by selectively driving the electron sources of the multi electron source.

An x-ray source (32) for performing energy discrimination within an imaging system (10) includes a cathode-emitting device (82) emitting electrons and an anode (81) that has a target (80) whereupon the electrons impinge to generate an x-ray beam (93) with multiple x-ray quantity energy peaks (116 and 120). A method of performing energy discrimination in the imaging system (10) includes emitting the electrons. The x-ray beam (93) with the x-ray quantity energy peaks (116 and 120) is generated. The x-ray beam (93) is directed through an object (44) and is received. An x-ray image having multiple energy differentiable characteristics is generated in response to the x-ray beam (93).

Systems and methods are provided for reconstructing projection data that is mathematically complete or sufficient acquired using a computed tomography (CT) system. In one embodiment, a set of projection data representative of a sampled portion of a cylindrical surface is provided. The set of projection data is reconstructed using a suitable cone-beam reconstruction algorithm. In another embodiment, two or more sets of spatially interleaved helical projection data are processed using helical interpolation. The helically interpolated set of projection data is reconstructed using a two-dimensional axial reconstruction algorithm or a three-dimensional reconstruction algorithm.

In a method and device for producing a tomosynthetic 3D x-ray image, a number of 2D projection images of an examination subject are acquired using a fixed x-ray source. The x-ray source has multiple, individually controllable emitters that respectively emit a single x-ray dose from various different directions. The tomosynthetic 3D image is reconstructed from the individual 2D projection images, and at least one 2D projection image is composed of multiple individual images.

An improved x-ray generation system produces a converging or diverging radiation pattern particularly suited for substantially cylindrical or spherical treatment devices. In an embodiment, the system comprises a closed or concave outer wall about a closed or concave inner wall. An electron emitter is situated on the inside surface of the outer wall, while a target film is situated on the outside surface of the inner wall. An extraction voltage at the emitter extracts electrons which are accelerated toward the inner wall by an acceleration voltage. Alternately, electron emission may be by thermionic means. Collisions of electrons with the target film causes x-ray emission, a substantial portion of which is directed through the inner wall into the space defined within. In an embodiment, the location of the emitter and target film are reversed, establishing a reflective rather than transmissive mode for convergent patterns and a transmissive mode for divergent patterns.

A novel x-ray treatment system utilizes one or more large area flat panel sources of x-ray radiation directed into a target zone. A target substance within the target zone is irradiated with x-ray radiation from the one or more flat panel sources, reducing the biological effects of a contaminant presence therein. The flat panel source comprises an electron source, an electron accelerator, and an electron target medium. The electron source may emit electrons either via field emission or thermionic emission. The x-ray source may operate in transmissive, reflective, or combined transmissive / reflective mode. The use of large area flat panel x-ray sources in the inventive systems allows for decreased installation and operational costs as well as increased efficiency.

An X-ray generating device includes an electron-beam generator, a target assembly group, and an electron-beam focusing unit. The electron-beam generator generates electron beams. The target assembly group includes a plurality of target assemblies that are arranged along a straight line in a direction in which X-rays are output; each of the target assemblies includes a target and a supporting member; the target generates X-rays from one of the electron beams generated by the electron-beam generator; and the supporting member supports the target by being disposed adjacent thereto. The electron-beam focusing unit focuses the electron beams onto the targets included in the target assembly group so that X-rays are generated in each of the target assemblies and output along the straight line after passing through the target assemblies.

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 imaging system has an x-ray source having an electron field emission source that emits an x-ray beam that strikes an elongated, stationary anode in an evacuated housing. A magnetic deflection system steers the electron beam between the electron field emission source and the anode, so that the electron beam can strike the anode at different locations, thereby causing x-rays to be emitted from those different locations, by controlling the degree of magnetic deflection. A radiation detector detects the x-rays after attenuation by an examination subject, and generates signals dependent on the detected radiation that represent an image of the subject.

A multi X-ray generating apparatus which has a plurality of electron sources arranged two-dimensionally and targets arranged at positions opposite to the electron sources includes a multi electron source which includes a plurality of electron sources and outputs electrons from driven electron sources by selectively driving a plurality of electron sources in accordance with supplied driving signals, and a target unit which includes a plurality of targets which generate X-rays in accordance with irradiation of electrons output from the multi electron source and outputs X-rays with different radiation qualities in accordance with the generation locations of X-rays. The generation locations and radiation qualities of X-rays from the target unit are controlled by selectively driving the electron sources of the multi electron source.

An x-ray generator capable of generating multiple selected spectra of x-rays to penetrate an object being studied is described. An x-ray detector designed so as to detect and / or image different x-ray spectra selectively is also described. Undesired spectral components can be rejected, and desired spectral components accepted for detection and / or imaging.

A multiple spot x-ray generator is provided that includes a plurality of electron generators. Each electron generator includes an emitter element to emit an electron beam, a meshed grid adjacent each emitter element to enhance an electric field at a surface of the emitter element, and a focusing element positioned to receive the electron beam from each of the emitter elements and focus the electron beam to form a focal spot on a shielded target anode, the shielded target anode structure producing an array of x-ray focal spots when impinged by electron beams generated by the plurality of electron generators. The plurality of electron generators are arranged to form an electron generator matrix that includes activation connections electrically connected to the plurality of electron generators, wherein each electron generator is connected to a pair of the activation connections to receive an electric potential therefrom.

The present specification discloses an X-ray scanning system with a non-rotating X-ray scanner that generates scanning data defining a tomographic X-ray image of the object and a processor executing programmatic instructions where the executing processor analyzes the scanning data to extract at least one parameter of the tomographic X-ray image and where the processor is configured to determine if the object comprises a liquid, sharp object, narcotic, currency, nuclear materials, cigarettes or fire-arms.

An X-ray source includes an electron-beam generating unit that generates an electron beam, and a transmission type target electrode to be irradiated with the electron beam to generate X-ray radiation. A plurality of convex portions each having an inclined surface with respect to an incident direction of the electron beam is formed on a surface of the transmission type target electrode.

An apparatus for modifying an aspect ratio of an electron beam to form a focal spot having a desired size and aspect ratio on a target anode is disclosed. The apparatus includes an emitter element configured to generate an electron beam having a first aspect ratio shape and an extraction electrode positioned adjacent to the emitter element to extract the electron beam out therefrom, the extraction electrode including an opening therethrough. The apparatus also includes at least one shaping electrode positioned to receive the electron beam after passing through the extraction electrode, the shaping electrode defining a non-circular aperture therein and being configured to provide at least one of shaping and focusing of the electron beam to have a second aspect ratio shape different from the first aspect ratio shape so as to form a focal spot having a desired size and aspect ratio on a target anode.

A system and method for addressing individual electron emitters in an emitter array is disclosed. The system includes an emitter array comprising a plurality of emitter elements arranged in a non-rectangular layout and configured to generate at least one electron beam and a plurality of extraction grids positioned adjacent to the emitter array, each extraction grid being associated with at least one emitter element to extract the at least one electron beam therefrom. The field emitter array system also includes a plurality of voltage control channels connected to the plurality of emitter elements and the plurality of extraction grids such that each of the emitter elements and each of the extraction grids is individually addressable. In the field emitter array system, the number of voltage control channels is equal to the sum of a pair of integers closest in value whose product equals the number of emitter elements.

An X-ray generating device includes an electron-beam generator, a target assembly group, and an electron-beam focusing unit. The electron-beam generator generates electron beams. The target assembly group includes a plurality of target assemblies that are arranged along a straight line in a direction in which X-rays are output; each of the target assemblies includes a target and a supporting member; the target generates X-rays from one of the electron beams generated by the electron-beam generator; and the supporting member supports the target by being disposed adjacent thereto. The electron-beam focusing unit focuses the electron beams onto the targets included in the target assembly group so that X-rays are generated in each of the target assemblies and output along the straight line after passing through the target assemblies.