Disclosed are methods and devices suitable for producing an electron beam.

Vacuum electron devices and linear accelerators include a hollow cathode configured to emit a beam of electrons. An anode is configured to attach and focus the beam of electrons. A control grid is configured to control the beam of electrons emitted from the hollow cathode. A cylinder is positioned substantially coaxial with the hollow cathode and is configured to maintain a shape and trajectory of the emitted beam of electrons.

Vacuum electron devices and linear accelerators include a hollow cathode configured to emit a beam of electrons. An anode is configured to attach and focus the beam of electrons. A control grid is configured to control the beam of electrons emitted from the hollow cathode. A cylinder is positioned substantially coaxial with the hollow cathode and is configured to maintain a shape and trajectory of the emitted beam of electrons.

A tunable photocathode for use in vacuum electronic devices includes a nanostructured photoemission layer including quantum confined nanostructures, such as quantum dots. The quantum confined nanostructures can be tuned (e.g., prepared to have various characteristics or parameters) in order to independently optimize various characteristics of the electron beam emitted by the photocathode. For example, by changing the material composition, size and geometry of the quantum confined nanostructures, the energy levels of the quantum confined nanostructures in the photoemission layer can be tuned to provide a photocathode having a high quantum efficiency, low emittance, fast response time to incident light pulses, long operational lifetime, and increased environmental stability compared with conventional photocathodes and cathodes in vacuum electronic devices.

An apparatus for attachment to a component of a microwave device, includes: a cage; a shield within the cage, wherein the shield is in a form of a container, at least a majority of the shield spaced away from an interior wall of the cage; and a connector at the cage, wherein the connector is configured to connect to a cable connection, and wherein the connector is electrically connected to two terminals within the shield. An apparatus for coupling to an input connection of an electron gun, the input connection having a heater terminal and a cathode terminal, the apparatus comprising: a connector having a first configured to attach to a cable, and a second end configured to connect to the input connection of the electron gun; and wherein the connector comprises an opening configured to receive the heater terminal of the input connection of the electron gun.

Example compact modular electron beam units are provided that can be used to generate electron beams using field emitter elements. A modular electron beam unit may comprise an electron beam source including a base portion, at least one field emitter element coupled to the base portion, the field emitter element including a field emitter tip, at least one gate electrode and a membrane window disposed over the at least one gate electrode.

Accelerator apparatus (100) for accelerating charged particles (2) with pulsed radiation includes horn-shaped coupling device (10) with at least one horn coupler (11, 15) having input aperture (12), electrically conductive walls (13) and output aperture (14), wherein pulsed radiation is received at input aperture and focused towards output aperture, and waveguide device (20) coupled with the output aperture and configured for receiving focused pulsed radiation. Waveguide device includes injection section (21) for providing charged particles and subjecting them to acceleration by pulsed radiation in injection section, and lateral output port (23) for releasing accelerated charged particles along particle acceleration direction. The at least one horn coupler receives linearly polarized single cycle pulses (1) including broadband frequency spectrum shaped as a linearly polarized plane wave and focuses linearly polarized single cycle pulses. Waveguide device has non-resonant broadband transmission characteristic. Furthermore, charged particle gun and method of accelerating charged particles are described.

Some embodiments include a system, comprising: a high voltage enclosure; a cathode disposed in the high voltage enclosure; an anode disposed in the high voltage enclosure; a plurality of grids disposed in the high voltage enclosure between the cathode and the anode; a voltage source configured to generate a common grid voltage; and a voltage divider disposed in the high voltage enclosure, configured to generate a plurality of grid voltages based on the common grid voltage, and configured to apply at least two of the grid voltages to the grids.

Some embodiments include a system, comprising: a high voltage enclosure; a cathode disposed in the high voltage enclosure; an anode disposed in the high voltage enclosure; a plurality of grids disposed in the high voltage enclosure between the cathode and the anode; a voltage source configured to generate a common grid voltage; and a voltage divider disposed in the high voltage enclosure, configured to generate a plurality of grid voltages based on the common grid voltage, and configured to apply at least two of the grid voltages to the grids.

To suppress both influence of electron emission from a cathode side surface and consumption of energy to be supplied to a heater, while being provided with a grid, an electron gun of the present invention includes: a cathode capable of emitting electrons by heating; a grid capable of controlling the electron emission; and a cathode shield which is an conductor including a material portion located in the vicinity of a side surface of the cathode and facing at least a portion of the side surface via a gap or a heat insulating material, and not being made in direct physical coupling nor in direct physical contact with the cathode.