An X-ray generation apparatus includes an electron gun having a cathode emitting an electron beam, a first housing accommodating the electron gun, a target on which the electron beam emitted from the electron gun is incident, a second housing accommodating the target, and an electron passage extending between the first housing and the second housing and configured to transfer the electron beam from a first internal space of the first housing to a second internal space of the second housing. The electron passage includes a diameter-reduced end portion decreasing in diameter toward the target. The first housing is provided with a first exhaust flow path for evacuating the first internal space in the first housing. The second housing is provided with a second exhaust flow path for evacuating the second internal space in the second housing.

An X-ray tube, including: an envelope (11) that holds inside thereof at a predetermined pressure; a filament (12) for emitting electrons and a focus electrode (13) provided in the envelope: and a target (15) for generating X-ray provided in the envelope facing to the filament (12) and the focus electrode (13), wherein the envelope (11) has an envelope body (11a) and an X-ray window portion (16) having a higher X-rays transmissivity and a higher electric conductivity than the envelope body (11a), when the X-ray window portion (16) or the anode (14) is set to a lower electric potential than both of an electric potential of the anode (14) or the X-ray window portion (16) and an electric potential of the filament (12) and the focus electrode (13), detection of at least one of an ion current (Ii) or an electron current (Ie) through the X-ray window portion (16) or the anode (14) is possible.

An electron gun includes a cathode including an electron emitting portion, an extraction electrode for extracting electrons emitted from the electron emitting portion, and a focusing electrode for focusing the electrons extracted by the extraction electrode. The focusing electrode includes an outside electrode having a tubular shape, and an inside electrode arranged inside the outside electrode. The inside electrode defines a first space having a columnar shape, and includes a first surface on a side of the cathode, and a second surface on an opposite side of the first surface. An inside surface of the outside electrode and the second surface of the inside electrode define a second space. The inside electrode includes an electron passage hole, and a communicating portion which makes the first space and the second space communicate with each other.

A method for generating X-ray radiation, the method including providing a liquid target in a chamber, directing an electron beam towards the liquid target such that the electron beam interacts with the liquid target to generated X-ray radiation, estimating a number of particles produced from the interaction between the electron beam and the liquid target by measuring a number of positively charged particles in the chamber and eliminating a contribution from scattered electrons to the estimated number of particles, and controlling the electron beam, and/or a temperature in a region of the liquid target in which the electron beam interacts with the target, such that the estimated number of particles is below a predetermined limit. Also, a corresponding X-ray source.

An X-ray tube, including: an envelope (11) that holds inside thereof at a predetermined pressure; a filament (12) for emitting electrons and a focus electrode (13) provided in the envelope: and a target (15) for generating X-ray provided in the envelope facing to the filament (12) and the focus electrode (13), wherein the envelope (11) has an envelope body (11a) and an X-ray window portion (16) having a higher X-rays transmissivity and a higher electric conductivity than the envelope body (11a), when the X-ray window portion (16) or the anode (14) is set to a lower electric potential than both of an electric potential of the anode (14) or the X-ray window portion (16) and an electric potential of the filament (12) and the focus electrode (13), detection of at least one of an ion current (Ii) or an electron current (Ie) through the X-ray window portion (16) or the anode (14) is possible.

An electron beam generator includes a cathode having a distal end portion emitting an electron beam, a first electrode accommodating the distal end portion, and a second electrode surrounding the first electrode when viewed from a direction along an emission axis of the electron beam. The first electrode has a first side wall surrounding the distal end portion. The second electrode has a second side wall separated from the first side wall and surrounding the first side wall. The first side wall is provided with a first opening portion allowing a first space surrounded by the first side wall and a second space between the first side wall and the second side wall to communicate with each other. The second electrode is provided with a second opening portion opening in the direction along the emission axis such that the second space and an external space communicate with each other.

In embodiments, a linac electron beam excited X-ray source weighing less than 50 pounds, and having a volume less than 1 cubic foot, injects electrons from an RF-excited, diamond tip cathode into a dielectric accelerator tube of diameter less than 10 mm, where the electrons are RF-accelerated to 1-4 MeV. A focusing channel having a plurality of annular permanent magnets can surround the dielectric tube, and a vacuum can be maintained in the tube by a getter pump. The accelerating RF can be 10 GHz or higher. The X-ray source can be powered by a rechargeable battery for more than an hour. Embodiments can be transported within a case having a display attached to an interior surface of its lid. An X-ray head can be removed from the case and extended up to 10 feet while remaining interconnected with the case by a flexible conduit.

X-ray generation tube includes electron gun, and anode having target to generate X-rays upon collision with electrons from the electron gun. The electron gun includes cathode having electron emitting portion, extraction electrode to extract the electrons from the electron emitting portion, and focusing electrode to focus the extracted electrons. The focusing electrode includes first portion having tubular shape, and second portion arranged inside the first portion. The first portion includes distal end facing the anode, the second portion includes opposing surface facing the anode, and the opposing surface includes electron passage hole through which the electrons from the electron emitting portion pass. Distance between the distal end and the anode is shorter than that between the opposing surface and the anode. Thermal conductivity of the distal end is lower than that of the second portion.

The object of the present invention is to provide a cold cathode X-ray tube capable of being driven stably over a long period of time by preventing temporal reduction in anode current. A cold cathode X-ray tube 1 comprises an electron emission part 10 including an electron emission element using a cold cathode, an anode part 11 disposed opposite to the electron emission part 10, a target 12 disposed on a part of a surface of the anode part 11, a housing 15 in which the electron emission part 10, the anode part 11, and the target 12 are disposed, and a hydrogen generation part 14 that is made of a material that generates hydrogen when receiving collision of electrons and disposed on a portion other than the surface of the target 12 out of surfaces existing in the housing 15.

An x-ray tube includes an electron emitter and a cathode cup having a recess that holds the electron emitter. The recess has a bottom surface, and a shield is positioned in the recess between the electron emitter and the bottom surface. The shield is configured to receive deposited sublimated emitter material and to maintain the sublimated emitter material away from the electron emitter.