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.

An emitter with a diameter of 100 nm or less is used with a protective cap layer and a diffusion barrier between the emitter and the protective cap layer. The protective cap layer is disposed on the exterior surface of the emitter. The protective cap layer includes molybdenum or iridium. The emitter can generate an electron beam. The emitter can be pulsed.

Disclosed herein is a system, comprising: a first X-ray source comprising a plurality of X-ray generators configured to respectively emit a plurality of X-rays toward an object; and a first X-ray detector configured to detect images of the object formed respectively by the plurality of X-rays from the first X-ray source.

A device and method for creating controlled radio frequency (RF) modulated X-ray radiation is described. The device includes an anode housed within a vacuum enclosure which acts to accelerate and convert an electron beam into X-ray radiation. A RF enclosure is housed within the vacuum enclosure and houses a field emission device, such as a carbon nanotube field emission device or similar cold cathode field emission device. The field emission device is biased to emit the electron beam from a field emission cathode via an extraction electrode in the RF enclosure towards the anode. Additionally an RF impedance matching and coupling circuit is connected electrically to the field emission device. The field emission device is thus directly driven with a RF signal to produce an RF modulated electron current to produce an RF modulated X-ray radiation.

Disclosed herein is an X-ray source, comprising: a cathode in a recess of a first substrate; a counter electrode on a sidewall of the recess, configured to cause field emission of electrons from the cathode; and a metal anode configured to receive the electrons emitted from the cathode and to emit X-ray from impact by the electrons on the metal anode.

An emitter (3) and a target (7) are arranged so as to face each other in a vacuum chamber (1), and a guard electrode (5) is provided at an outer circumferential side of an electron generating portion (31) of the emitter (3). The emitter (3) is supported movably in both end directions of the vacuum chamber (1) by the emitter supporting unit (4) having a movable body (40). The emitter supporting unit (4) is operated by an operating unit (6) connected to the emitter supporting unit (4). By operating the emitter supporting unit (4) by the operating unit (6), a distance between the electron generating portion (31) of the emitter (3) and the target (7) is changed, and a position of the emitter (3) is fixed at an arbitrary distance, then field emission is performed with the position of the emitter (3) fixed.

The present invention provides an X-Ray emitting device that comprises a focusing electrode composed of a ceramic-based material, which can be manufactured by a simple process and is excellent in durability.

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). Guard electrode (5) is supported movably in directions of both ends of vacuum chamber (1) by guard electrode supporting unit (6). To perform regeneration process of guard electrode (5), guard electrode (5) is moved to opening (22) side (to separate position) by operating guard electrode supporting unit (6), and a 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 performing regeneration process, by operating guard electrode supporting unit (6) again, guard electrode (5) is moved to opening (21) side (to emitter position), and a state in which field emission of electron generating portion (31) is possible is set.