An electron gun comprising a cathode having an electron emitting surface and whose planar shape is circular, a heater to increase the temperature of the cathode, and an anode to apply a positive electric potential relative to the cathode to extract electrons in a predetermined direction is provided. The cathode comprises a through hole at a central portion thereof along a central axis of the cathode, and either the cathode comprises a no-emitting layer at at least one of an opening edge on the electron emitting surface side of the through hole and an inner surface of the through hole, or the opening edge on the electron emitting surface side of the through hole is a chamfered C surface or a chamfered R surface.

A cathode assembly for emitting charged particles, used in for example an electron gun as source for generating an electron beam is provided. The cathode assembly has a cathode including an emitting member and a carrier. The emitting member is mounted in the carrier, and the carrier is electrically connected to a holder. The cathode is heated by irradiation from an external source, whereby the emitting member emits charged particles from an emitting surface at an emitting temperature. The connection between the carrier and the holder provides a thermal barrier for reducing the amount of thermal energy transferred from the cathode to the holder.

A cathode assembly for emitting charged particles, used in for example an electron gun as source for generating an electron beam is provided. The cathode assembly has a cathode including an emitting member and a carrier. The emitting member is mounted in the carrier, and the carrier is electrically connected to a holder. The cathode is heated by irradiation from an external source, whereby the emitting member emits charged particles from an emitting surface at an emitting temperature. The connection between the carrier and the holder provides a thermal barrier for reducing the amount of thermal energy transferred from the cathode to the holder.

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 method of controlling the performance of a night vision device includes storing, in memory of the night vision device, a plurality of performance configuration parameters, and after the storing, applying at least one of a hardware lock and a software lock to the night vision device such that at least some of the plurality of performance configuration parameters stored in the memory cannot be changed.

A method of controlling the performance of a night vision device includes storing, in memory of the night vision device, a plurality of performance configuration parameters, and after the storing, applying at least one of a hardware lock and a software lock to the night vision device such that at least some of the plurality of performance configuration parameters stored in the memory cannot be changed.

An electron emission source is provided. The electron emission source comprises a first electrode, an insulating layer, a semiconductor layer, and a second electrode. The first electrode, the insulating layer, the semiconductor layer, and the second electrode are successively stacked with each other. The second electrode is a graphene layer, and the graphene layer is an electron emission end to emit electrons.

Radial radio frequency (RF) electron guns and radial RF electron gun systems are provided that are capable of generating an electron beam that can propagate either radially inward, towards the axis of a cylinder, or radially outward from the axis. A beam source capable of generating a radially inwardly propagating electron beam, while perhaps not particularly useful as a source for a higher-energy accelerator, offers potential advantages for materials processing, as the geometry allows irradiation from all sides of an enclosed material flow with a single structure. Other potential applications include, but are not limited to, atmospheric plasma generation, radiation damage testing, and possibly, novel electron lens-type devices for hadron accelerators.

Radial radio frequency (RF) electron guns and radial RF electron gun systems are provided that are capable of generating an electron beam that can propagate either radially inward, towards the axis of a cylinder, or radially outward from the axis. A beam source capable of generating a radially inwardly propagating electron beam, while perhaps not particularly useful as a source for a higher-energy accelerator, offers potential advantages for materials processing, as the geometry allows irradiation from all sides of an enclosed material flow with a single structure. Other potential applications include, but are not limited to, atmospheric plasma generation, radiation damage testing, and possibly, novel electron lens-type devices for hadron accelerators.