Provided herein is a field emission device. The field emission device includes a cathode which is connected to a negative power supply and emits electrons, an anode which is connected to a positive power supply and includes a target material receiving the electrons emitted from the cathode, and a ground electrode which is formed to face the anode and has an opening through which the electrons emitted from the cathode pass. The ground electrode is grounded so that when an arc discharge occurs due to high voltage operation of the anode, electric charge produced by the arc discharge is emitted to a ground.

Disclosed is a field emission apparatus. The apparatus comprises a cathode electrode and an anode electrode spaced apart from each other, an emitter on the cathode electrode, a gate electrode between the cathode and anode electrodes and including at least one gate aperture overlapping the emitter, and an electron transmissive sheet on the gate electrode and including a plurality of fine openings overlapping the gate aperture.

An x-ray tube casing is provided which includes a housing having a heat exchanger integrally formed thereon in an additive manufacturing process. The additive manufacturing process allows for tight tolerances with regard to the structure for the casing and the internal passages of the heat exchanger to significantly reduce the size and weight of the casing. The casing additionally includes a fluid distribution manifold that effectively distributes the cooling fluid within the casing to more efficiently provide cooling to the x-ray tube insert disposed within the casing.

The present disclosure relates to an X-ray source apparatus and a control method of the X-ray source apparatus in which a cathode electrode and a gate electrode are arranged in an array form to enable matrix control, and, thus, it is possible to irradiate X-rays at an optimum dose for each position on the subject. Therefore, it is possible to suppress the irradiation of more X-rays than are needed to the subject. Also, it is possible to obtain a high-resolution and high-quality X-ray image. As such, two-dimensional matrix control makes it easy to control the dose of X-rays and makes it possible to uniformly irradiate X-rays to the subject. Therefore, it is possible to manufacture a high-resolution surface X-ray source with less dependence on the size of the focus of electron beams.

The present invention generally relates to an x-ray source and specifically to an x-ray source suitable for large area x-ray generation. The invention also relates to a system comprising such an x-ray source.

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 and side being restrained by movement restraining unit (6).

An x-ray tube can include an electron-emitter, which can include a tube-shape with a minimum inside diameter of at least 0.5 millimeters. The electron-emitter can provide field-emission of electrons, and thus can avoid the electrical power required for heating, and can avoid degradation due to high temperature of, a thermionic-emission electron-emitter. This type of electron-emitter, with a tube-shape, can have a relatively large electron-emission region, allowing high electrical current without excessive current density.

In the present invention, a ferroelectric body is irradiated with ultraviolet light, and the ferroelectric body is caused to stably generate electric potential. A method for radiating charged particles, in which the UV-light-receiving surface of the ferroelectric body that receives UV light and is caused to generate a potential difference is irradiated with UV light having a wavelength not transmitted by the ferroelectric body, and charged particles are radiated from the charged-particle-radiation surface of the ferroelectric body, wherein the UV-light-receiving surface is irradiated with pulses of UV light at a peak power of 1 MW or greater. The pulse width of the UV light is measured in picoseconds (less than 110.sup.9 seconds), and the UV pulses can be transmitted by fiber.

Opening edge surface (45a) of an emitter supporting unit female screw bore (45) provided at an emitter supporting unit (4) extends along radial direction of the emitter supporting unit female screw bore (45). An emitter supporting unit operation hole (32) provided at a flange portion (30a) of a vacuum enclosure (11) has shape into which one selected from a position adjustment shaft (6) and a pressing shaft (9) can be inserted from their shaft tip sides. The position adjustment shaft is provided, on an outer circumferential surface of its tip (61), with a tip side male screw portion (61a) that can be screwed into the emitter supporting unit female screw bore (45). The pressing shaft has, at its tip (91), a tip surface (91a) having a larger diameter than an opening diameter of the emitter supporting unit female screw bore (45) and extending along radial direction of the pressing shaft.

A portable x-ray imaging source (100) capable of motion-free x-ray tomosynthesis, wherein said source is suitable for dental and small body-part/small area imaging.