A photonic electron emission device includes an emitter, a photonic energy conduit evanescently coupled to the emitter, and an anode. The emitter includes a component selected from the group consisting of a metal, a semimetal, a semiconductor having a bandgap that is less than about 3.5 eV. The anode is positively biased with respect to the emitter, the anode directing electrons emitted from the emitter.

The present invention refers to a device for generating charged particle beams with tunable orbital angular momentum. The device firstly includes one or more components for providing a charged particle beam. It is further characterized by an electrical arrangement for imparting a tunable orbital angular momentum to the charged particle beam during operation. The orbital angular momentum of the produced charged particle vortex beam is tunable by adjusting the amount of electrical current. The chirality of the produced charged particle vortex beam is switchable by reversing the direction of the electrical current. The generation of the charged particle vortex beam from the present invention does not depend on the energy of the charged particle beams. The generation of the charged particle vortex beams from the present invention is predictable and reproducible.

A photocathode for use in vacuum electronic devices has a bandgap gradient across the thickness (or depth) of the photocathode between the emitting surface and the opposing surface. This bandgap gradient compensates for depth-dependent variations in transport energetics. When the bandgap energy E.sub.BG(z) is increased for electrons with shorter path lengths to the emitting surface and decreased for electrons with longer path lengths to the emitting surface, such that the sum of E.sub.BG(z) and the scattering energy is substantially constant or similar for electrons photoexcited at all locations within the photocathode, the energies of the emitted electrons may be more similar (have less variability), and the emittance of the electron beam may be desirably decreased. The photocathode may be formed of a III-V semiconductor such as InGaN or an oxide semiconductor such as GaInO.

Controlling total emission current of an electron emitting construct in an x-ray emitting device by providing a cathode, providing multiple active areas each active area having a gated cone electron source, including multiple emitter tips arranged in an array, a gate electrode, and a gate interconnect lead connected to the gate electrode, providing an x-ray emitting construct comprising an anode, the anode being an x-ray target, situating the x-ray emitting construct facing the active areas face each other, selecting a set of active areas, and activating selected active areas by conductively connecting a voltage source to their associated the gate electrode interconnect lead.

The disclosure relates to an image capture device comprising an electron receiving construct and an electron emitting construct, and further comprising an inner gap providing an unobstructed space between the electron emitting construct and the electron receiving construct. The disclosure further relates to an x-ray emitting device comprising an x-ray emitting construct and an electron emitting construct, said x-ray emitting construct comprising an anode, the anode being an x-ray target, wherein the x-ray emitting device may comprise an inner gap providing an unobstructed space between the electron emitting construct and the x-ray emitting construct. The disclosure further relates to an x-ray imaging system comprising an image capture device and an x-ray emitting device.

Provided is a photocathode kit that does not require adjustment of the distance between a photocathode film and a lens focusing on the photocathode film when the photocathode and the lens are installed inside an electron gun. The photocathode kit includes: a photocathode including a substrate in which a photocathode film is formed on a first surface; a lens; and a holder that holds the substrate and the lens, and the holder has a retaining member that retains the photocathode film and the lens to be spaced apart by a predetermined distance, and a first communication path that communicates between inside of the holder and outside of the holder.

The inventive concept relates to an apparatus for aging a field emission device configured to emitting electrons based on an electric field between a first electrode and a second electrode, and an aging method thereof. The apparatus according to an embodiment of an inventive concept includes a voltage generator and a current controller. The voltage generator increases the voltage applied to the first electrode to the target voltage level during the first time. The current controller increases the field emission current for the second time to the target current level and increases the pulse width of the field emission current for the third time to the target pulse width. According to the inventive concept, the performance of a large field emission device may be improved with high efficiency and low cost.

An electron emitter structure includes an electron emission layer which is arranged to have a first side and a second side, and an electron accelerating structure which is arranged on the first side of the electron emission layer. The electron emission layer has a mixture of metals so as to be atmospherically stable. The electron accelerating structure has at least one electrode which is electrically insulated from the electron accelerating structure so as to form an acceleration path which allows electrons which are released from the electron emission layer to be selectively accelerated upon generation of an adjustable electric field. The acceleration path has a length l of from 10 nm to 1 ?m.

A photonic electron emission device includes an emitter, a photonic energy conduit evanescently coupled to the emitter, and an anode. The emitter includes a component selected from the group consisting of a metal, a semimetal, a semiconductor having a bandgap that is less than about 3.5 eV. The anode is positively biased with respect to the emitter, the anode directing electrons emitted from the emitter.

An object is to provide an electron gun that makes it possible to verify whether or not an electron beam emitted form a photocathode is misaligned from a designed emission center axis. The object can be achieved by an electron gun including: a light source; a photocathode; and an anode. The electron gun includes an intermediate electrode arranged between the photocathode and the anode, an electron beam shielding member configured to block a part of an electron beam, a measurement unit configured to measure an intensity of an electron beam blocked by the electron beam shielding member, and an electron beam emission direction deflector arranged between the anode and the electron beam shielding member and configured to change a position where an electron beam that passed through the anode reaches the electron beam shielding member. The intermediate electrode has an electron beam passage hole and a drift space.