An electron emitter that consists of: a low work function material including Lanthanum hexaboride or Iridium Cerium that acts as an emitter, a cylinder base made of high work function material that has a cone shape where the low work function material is embedded in the high work function material but is exposed at end of the cone and the combined structure is heated and biased to a negative voltage relative to an anode, an anode electrode that has positive bias relative to the emitter, and a wehnelt electrode with an aperture where the cylindrical base protrudes through the wehnelt aperture so the end of the cone containing the emissive area is placed between the wehnelt and the anode.

An electron beam apparatus includes: a cathode configured to emit electrons; an anode that is an electrode which forms an electric field such that an electron beam is formed by the electrons emitted from the cathode, and that is formed with a first hole through which the electron beam passes; an aperture member formed with an opening that shades a part of the electron beam which passes through the anode; and a convergence electrode that is an electrode which forms an electric field such that the electron beam which passes through the opening converges, and that is configured to include one single-hole electrode formed with a second hole through which the electron beam passes.

An electron emitter that consists of: a low work function material including Lanthanum hexaboride or Iridium Cerium that acts as an emitter, a cylinder base made of high work function material that has a cone shape where the low work function material is embedded in the high work function material but is exposed at end of the cone and the combined structure is heated and biased to a negative voltage relative to an anode, an anode electrode that has positive bias relative to the emitter, and a wehnelt electrode with an aperture where the cylindrical base protrudes through the wehnelt aperture so the end of the cone containing the emissive area is placed between the wehnelt and the anode.

The present invention relates to an electron gun cathode mount adapted at one end to secure a thermionic cathode and at the other end to be connected to an attachment member, wherein the electron gun cathode mount is structured so as to be capable of, when in use, reducing heat transfer from the thermionic cathode to the attachment member, and the material forming the electron gun cathode mount has a thermal conductivity of less than 10 Wm.sup.1K.sup.1 at the operating temperature of the thermionic cathode in a direction from the thermionic cathode to the attachment member. The present invention also relates to an electron gun assembly having the electron gun cathode mount installed therein.

A device for converting light into an electron current emission is described. The device includes a substrate having first and second opposing surfaces. At least one antenna is disposed on the substrate. The at least one antenna is configured to absorb energy from photons having a selected wavelength. At least one dimension of the at least one antenna is a resonant length based on the selected wavelength. In response to photons incident thereon, at least a portion of the at least one antenna is heated to a degree which results in a thermionic emission from the antenna. The device also include at least one collector spaced apart from the at least one antenna by a selected distance. The at least one collector is configured to receive a Schottky emission from the at least one antenna. The received Schottky emissions may be used to signal a photon detection.