A C-arm X-ray apparatus includes an x-ray emitter (5) and an X-ray detector (4) which are maintained on a C-arm (2) mounted on a reference plane. The x-ray emitter (5) has nanorods as electron emitters and has an elongated structure which is at least partially aligned along a surface normal of the reference plane.

A flat emitter, in an embodiment, includes an emitter surface to emit electrons when a filament current is applied; a first end region including at least one first connection leg; and a second end region including at least one second connection leg. According to an embodiment, at least one connection leg is embodied as a band-type connection leg and is torsioned at an angle in a longitudinal axis. According to an embodiment, the first connection leg and the second connection leg are embodied as band-type connection legs and in each case are torsioned at a definable angle in a longitudinal axis. As a result, a simply constructed flat emitter in terms of design is achieved, with a longer service life and a high level of electron emission.

A system for compensating for a back emission current in an X-ray generator is provided. The system includes a transformer, a common, and a voltage source. The transformer is operative to provide power to an electron emitter of the X-ray generator. The common is electrically coupled to an anode of the X-ray generator. The anode is operative to receive electrons emitted by the electron emitter such that the back emission current is generated between the common and the electron emitter. The voltage source electrically couples the common to the transformer and is operative to generate an offset voltage that reduces the back emission current.

A robust cold cathode uses an electron emitting construct design possibly for an x-ray emitter device. The electron beam emitted by the emitting construct is focused and accelerated by an electrical field towards an electron anode target. A shield is provided to prevent a cold cathode from being damaged by ion bombardment in high-voltage applications and a non-emitter zone may provide a robust ion bombardment zone. The system is further configured to provide an angled target anode or a stepped target anode to further reduce the ion bombardment damage.

Provided is a field emission device. The field emission device includes a cathode electrode having a first surface and a second surface facing the first surface, the cathode electrode including grooves that are recessed from the first surface toward the second surface, the grooves extending in a first direction parallel to the first surface and emitter structures which are disposed within the grooves and each of which includes a core extending in the first direction and a conductive wire configured to surround the core. The grooves may be arranged in a second direction crossing the first direction, and the emitter structures may be disposed at vertical levels different from each other.

The present invention provides an emitter, which comprises carbon nanotubes and is excellent in the efficiency of electron emission, and an X-ray tube comprising the same.

A vacuum electron tube comprises at least one electron-emitting cathode and at least one anode arranged in a vacuum chamber, the cathode having a planar structure comprising a substrate comprising a conductive material, a plurality of nanotube or nanowire elements electrically insulated from the substrate, the longitudinal axis of the nanotube or nanowire elements substantially parallel to the plane of the substrate, and at least one first connector electrically linked to at least one nanotube or nanowire element so as to be able to apply a first electrical potential to the nanowire or nanotube element.

An embodiment of the inventive concept provides an X-ray tube including a chamber having a hollow pillar shape using a first axis as a central axis, a cathode electrode disposed on a bottom surface of the chamber, an emitter provided at a position at which the cathode electrode meets the first axis, an anode electrode including a through-hole using the first axis as a central axis and a target layer inclined to the first axis, a gate electrode disposed between the cathode electrode and the anode electrode and having an opening exposing the emitter, a focusing electrode disposed between the gate electrode and the anode electrode, a window spaced apart from the target layer of the anode electrode, and a window electrode provided on a top surface of the chamber to fix a side surface of the window. Here, the window electrode is grounded.

A source for generating ionizing radiation and in particular x-rays, to an assembly includes a plurality of sources and to a process for producing the source. The source for generating ionizing radiation comprises: a vacuum chamber; a cathode that is able to emit an electron beam into the vacuum chamber; an anode that receives the electron beam and that comprises a target that is able to generate ionizing radiation from the energy received from the electron beam; and an electrode that is placed in the vicinity of the cathode and forming a wehnelt. The electrode is formed from a conductive surface adhering to a concave face of a dielectric.

A source for generating ionizing radiation and in particular x-rays, to an assembly includes a plurality of sources and to a process for producing the source. The source comprises: a vacuum chamber; a cathode that is able to emit an electron beam into the vacuum chamber, the electron beam developing about an axis; and an anode that receives the electron beam and that comprises a target that is able to generate ionizing radiation from the energy received from the electron beam; the ionizing radiation being generated toward the exterior of the vacuum chamber; the anode comprises a cavity into which the electron beam is intended to penetrate to reach the target and the walls of the cavity form a Faraday cage blocking parasitic ions that may be emitted by the target into the interior of the vacuum chamber; and at least one getter that is separate from the walls of the cavity and that is intended to trap the parasitic ions is placed in the cavity.