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.

Large-area individually addressable multi-beam x-ray system and method of forming same

Computed tomography device comprising an x-ray source and an x-ray detecting unit. The x-ray source comprises a cathode with a plurality of individually programmable electron emitting units that each emit an electron upon an application of an electric field, an anode target that emits an x-ray upon impact by the emitted electron, and a collimator. Each electron emitting unit includes an electron field emitting material. The electron field emitting material includes a nanostructured material or a plurality of nanotubes or a plurality of nanowires. Computed tomography methods are also provided.

Computed tomography system for imaging of human and small animal

Stationary x-ray digital breast tomosynthesis systems and related methods are disclosed. According to one aspect, the subject matter described herein can include an x-ray tomosynthesis system having a plurality of stationary field emission x-ray sources configured to irradiate a location for positioning an object to be imaged with x-ray beams to generate projection images of the object. An x-ray detector can be configured to detect the projection images of the object. A projection image reconstruction function can be configured to reconstruct tomography images of the object based on the projection images of the object.

Stationary x-ray digital breast tomosynthesis systems and related methods

Methods and apparatus for independent control of electron emission current and x-ray energy in x-ray tubes are 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.

Method and apparatus for controlling electron beam current

An X-ray tube includes a radiopaque substrate including a window portion, an X-ray transmission window closing the window portion, an X-ray target provided at the window portion from an inner surface side of the substrate, a highly-evacuated container portion attached to the inner surface of the substrate, a cathode, a first control electrode and a second control electrode provided inside the container portion. A shielding electrode is provided at the inner surface of the substrate so as to surround the window portion. Electrons collide with the X-ray target to generate X-rays. Electrons reflected on the X-ray target between the shielding electrodes are absorbed by the shielding electrodes, so an inner surface of the container portion is not charged. The electron emission from the cathode is not affected by the reflected electrons, so a change in target current is small, and thus X-rays of substantially constant intensity can be radiated.

X-ray tube

An X-ray generator includes a cathode having an emitter made of carbon nanotubes which emits electrons by field emission and thus becomes a cold cathode electron emission source In the invention using the carbon nanotubes, any one of the following three forms is adopted to control the tube current apart from the electron-focusing control The first form is that a takeoff electrode is disposed near the cathode and the Wehnelt potential and the takeoff electrode potential are controlled independently The second form is that an electron emission source is disposed behind the cathode and the electron emission source emits electrons which collide against the back of the cathode so that the cathode temperature is controlled in a range of the room temperature to about 100 degrees Celsius to regulate an amount of electron emission from the cathode The third form is that the cathode has a heater so that the cathode temperature is controlled in a range of the room temperature to about 100 degrees Celsius to regulate an amount of electron emission from the cathode

X-ray generator

An X-ray Talbot-Lau interferometer scanning setup consisting of three transmission gratings, a laboratory-based X-ray source that emits X-rays vertically, and an image detector on the top has been developed for the application of X-ray phase imaging to moving objects that cannot be tested clearly with conventional absorption contrast. The grating-based X-ray phase imaging method usually employs a phase-stepping (or fringe-scanning) technique by displacing one of the gratings step-by-step while the object stays still. Since this approach is not compatible with a scanner-type application for moving objects, we have developed a new algorithm for achieving the function of phase-stepping without grating displacement. By analyzing the movie of the moire pattern as the object moves across the field of view, we obtain the absorption, differential phase, and visibility images. The feasibility of the X-ray phase imaging scanner has been successfully demonstrated for a long sample moving at 5 mm/s. This achievement is a breakthrough for the practical industrial application of X-ray phase imaging for screening objects carried on belt-conveyers such as those in factories.

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Laboratory-based X-ray phase-imaging scanner using Talbot-Lau interferometer for non-destructive testing.

PROBLEM TO BE SOLVED: To provide an X-ray generator for stably emitting a characteristic X-ray of a minute spot around 10-20 μmϕ at a low angle without being influenced by variation of the position of an electron beam around several μm. SOLUTION: This X-ray generator includes: a tube body structured to allow the inside to be brought into a vacuum state; an electron source generating an electron beam in the tube body; and target members arranged in the tube body for generating an X-ray by being irradiated with the electron beam emitted from the electron source. The X-ray generator is characteristically structured such that the target members 3a and 3b are formed by embedding a plurality of repeated minute-width stripe-like metal thin films 32 in base materials 31 and 31a, and a specific stripe-like metal thin films is irradiated with the electron beam, whereby a characteristic X-ray is emitted at a low angle from the specific stripe-like metal thin film to the outside through an X-ray window 12. COPYRIGHT: (C)2009,JPO&INPIT

X-ray generator, x-ray analysis device, x-ray transmission image measurement device, and x-ray interferometer

An X-ray tube includes an electron gun in which a Wehnelt electrode is formed with an opening asymmetric about an electron emitter. The electron emitter is an elongate coil filament which is disposed inside the elongate opening of the Wehnelt electrode. The opening has two longer sides positioned asymmetrically about a center-of-width line of the filament. Each of the two longer sides is curved in the same direction as viewed in a direction normal to the front face of the Wehnelt electrode. The two longer sides have curvature radii R 1 and R 2 different from each other, so that an electron-beam-irradiation region on a target is not curved but becomes almost straight.

X-ray phase imaging based on X-ray Talbot-Lau interferometry is an emerging nondestructive testing (NDT) method applicable to materials consisting of light elements such as organic and plastic materials. Aiming at future application to the examination of objects carried on conveyor systems, a scanner-type X-ray phase imaging apparatus is developed. Following the verification of the algorithm for phase-scanner image formation (S. Bachche et al., Sci. Rep., 2017), we report on a development with a desk-sized compact configuration and a 200-mm-wide field of view. Gratings used to construct an X-ray Talbot-Lau interferometer are bent and tiled. A scan speed of 9.2 mm/s with a spatial resolution of 0.29 mm is achieved in resultant images of absorption and scattering. Three scattering images are obtained for a carbon fiber reinforced plastic sample by changing its orientation against the gratings to visualize anisotropic fibrous structures.

Masaru Kuribayashi

Papers

X-ray generator

Laboratory-based X-ray phase-imaging scanner using Talbot-Lau interferometer for non-destructive testing.

X-ray generator, x-ray analysis device, x-ray transmission image measurement device, and x-ray interferometer

X-ray tube

X-ray phase-imaging scanner with tiled bent gratings for large-field-of-view nondestructive testing