Graphene grids are configured for applications in vacuum electronic devices. A multilayer graphene grid is configured as a filter for electrons in a specific energy range, in a field emission device or other vacuum electronic device. A graphene grid can be deformable responsive to an input to vary electric fields proximate to the grid. A mesh can be configured to support a graphene grid.

The present disclosure is directed to an electron source and an X-ray source using the same. The electron source of the present invention comprises: at least two electron emission zones, each of which comprises a plurality of micro electron emission units, wherein the micro electron emission unit comprises: a base layer, an insulating layer on the base layer, a grid layer on the insulating layer, an opening in the grid layer, and an electron emitter that is fixed at the base layer and corresponds to a position of the opening, wherein the micro electron emission units in the same electron emission zone are electrically connected and simultaneously emit electrons or do not emit electrons at the same time, and wherein different electron emission zones are electrically partitioned.

An apparatus is provided for generating X-ray radiation in an outer magnetic field, which may be generated by a magnetic field device. The apparatus includes a cathode configured to generate an electron beam and an anode configured to retard the electrons of the electron beam and generate an X-ray beam. The apparatus further includes a device configured to generate an electric field orientated from the anode in the direction of the cathode and substantially collinear to the outer magnetic field, wherein the cathode, as an electron emitter, includes a cold cathode that passively provides free electrons by field emission.

An apparatus is provided for generating X-ray radiation in an outer magnetic field, which may be generated by a magnetic field device. The apparatus includes a cathode configured to generate an electron beam and an anode configured to retard the electrons of the electron beam and generate an X-ray beam. The apparatus further includes a device configured to generate an electric field orientated from the anode in the direction of the cathode and substantially collinear to the outer magnetic field, wherein the cathode, as an electron emitter, includes a cold cathode that passively provides free electrons by field emission.

The disclosure relates to a detecting system including a terahertz wave source, a detector and a controlling computer. The terahertz wave source includes a terahertz reflection klystron including an electron emission unit, a resonance unit, an output unit. The electron emission unit is configured to emit electrons. The resonance unit includes a resonant cavity communicated with the electron emission unit so that the electron emission unit emit electrons into the resonant cavity. The resonant cavity of the electron emission unit opposite the cavity wall has an output aperture coupled. The output unit is communicated with the resonance unit by the output aperture coupled. The resonance unit generate terahertz wave transmit to the output unit by the output aperture coupled.

A Tera Hertz reflex klystron includes an electron emission unit, a resonant unit and an output unit. The electron emission is used to emit a plurality of electrons. The electron emission unit defines a first opening. The resonant unit comprises a resonant cavity frame. The resonant cavity frame comprises a top wall and a bottom wall and defines a resonant cavity. The top wall and the bottom wall faces with each other. The bottom wall comprises a bottom opening. The top wall comprises a top opening and at least one outputting hole. The bottom opening and the first opening are merged with each other. The output unit being configured to output Tera Hertz waves. The plurality of electrons are transferred to the output unit from the at least one outputting hole.

Graphene grids are configured for applications in vacuum electronic devices. A multilayer graphene grid is configured as a filter for electrons in a specific energy range, in a field emission device or other vacuum electronic device. A graphene grid can be deformable responsive to an input to vary electric fields proximate to the grid. A mesh can be configured to support a graphene grid.

The present disclosure is directed to an electron source and an X-ray source using the same. The electron source of the present invention comprises: at least two electron emission zones, each of which comprises a plurality of micro electron emission units, wherein the micro electron emission unit comprises: a base layer, an insulating layer on the base layer, a grid layer on the insulating layer, an opening in the grid layer, and an electron emitter that is fixed at the base layer and corresponds to a position of the opening, wherein the micro electron emission units in the same electron emission zone are electrically connected and simultaneously emit electrons or do not emit electrons at the same time, and wherein different electron emission zones are electrically partitioned.

A field emission cathode device and method for forming a field emission cathode device involve a cathode element having a field emission surface, and a gate electrode element disposed in spaced-apart relation to the field emission surface of the cathode element so as to define a gap therebetween, with the gate electrode element having a plurality of parallel grill members or a mesh structure laterally-extending between opposing anchored ends. A film element laterally co-extends and is engaged with the gate electrode element, with the film element being arranged to allowed electrons emitted from the field emission surface of the cathode element to pass therethrough, and to cooperate with the gate electrode element and the cathode element to form a substantially uniform electric field within the gap and about the field emission surface.

A field emission electron source includes a linear carbon nanotube structure, an insulating layer and at least one conductive ring. The linear carbon nanotube structure has a first end and a second end. The insulating layer is located on outer surface of the linear carbon nanotube structure. The first conductive ring includes a first ring face 1301 and a second ring face, an end surface of the linear carbon nanotube structure, and the first ring face are coplanar.