A photoelectric-surface electron source includes: a glass substrate that receives laser light from a substrate light-receiving surface including microlenses and that focuses the laser light toward a substrate main surface located on the opposite side from the substrate light-receiving surface; a photoelectric surface that is provided to the substrate main surface, and that receives the focused laser light and emits photoelectrons; and an extraction electrode that is fixed to the substrate main surface and that extracts the photoelectrons from the photoelectric surface. The extraction electrode is disposed away from the photoelectric surface along the normal direction of the substrate main surface and has: an electrode part in which electrode holes for allowing the photoelectrons to pass therethrough are provided; and a frame part that is fixed to a region surrounding the photoelectric surface in the substrate main surface.

A photoelectric-surface electron source includes: a glass substrate that receives laser light from a substrate light-receiving surface including microlenses and that focuses the laser light toward a substrate main surface located on the opposite side from the substrate light-receiving surface; a photoelectric surface that is provided to the substrate main surface, and that receives the focused laser light and emits photoelectrons; and an extraction electrode that is fixed to the substrate main surface and that extracts the photoelectrons from the photoelectric surface. The extraction electrode is disposed away from the photoelectric surface along the normal direction of the substrate main surface and has: an electrode part in which electrode holes for allowing the photoelectrons to pass therethrough are provided; and a frame part that is fixed to a region surrounding the photoelectric surface in the substrate main surface.

In some embodiments, a gas discharge tube (GDT) can include first and second electrodes each including an edge and an inward facing surface, such that the inward facing surfaces of the first and second electrodes face each other. The GDT can further include a sealing portion implemented to join and seal the edge portions of the inward facing surfaces of the first and second electrodes to define a sealed chamber between the inward facing surfaces of the first and second electrodes. The GDT can further include an electrically insulating portion implemented to provide a surface in the sealed chamber and to cover a portion of the inward facing surface of each of at least one of the first and second electrodes such that a leakage path within the sealed chamber includes the surface of the electrically insulating portion.

An annular cathode for a vacuum tube includes a central cylindrical support whose axis is that of the cathode; an outer peripheral electron emitter with annular section whose axis is that of the cathode, extending over the outer perimeter of the cathode; and a folded skirt, secured at an inner end to the central support, and secured, at its outer end, to a plurality of lugs; each lug being disposed in series with the folded skirt, and secured with the folded skirt and with the inner surface of the electron emitter.

An annular cathode for a vacuum tube includes a central cylindrical support whose axis is that of the cathode; an outer peripheral electron emitter with annular section whose axis is that of the cathode, extending over the outer perimeter of the cathode; and a folded skirt, secured at an inner end to the central support, and secured, at its outer end, to a plurality of lugs; each lug being disposed in series with the folded skirt, and secured with the folded skirt and with the inner surface of the electron emitter.

An annular cathode for a vacuum tube includes a central cylindrical support whose axis is that of the cathode; an outer peripheral electron emitter with annular section whose axis is that of the cathode, extending over the outer perimeter of the cathode; and a folded skirt, secured at an inner end to the central support, and secured, at its outer end, to a plurality of lugs; each lug being disposed in series with the folded skirt, and secured with the folded skirt and with the inner surface of the electron emitter.

An apparatus includes: a structure having a lumen for accommodating a beam (e.g., electron beam, proton beam, or a charged particle beam), wherein the structure is a component of a medical radiation machine having a target for interaction with the beam to generate radiation; and a first beam position monitor comprising a first electrode and a second electrode, the first electrode being mounted to a first side of the structure, the second electrode being mounted to a second side of the structure, the second side being opposite from the first side; wherein the first beam position monitor is located upstream with respect to the target.

An apparatus includes: a structure having a lumen for accommodating a beam (e.g., electron beam, proton beam, or a charged particle beam), wherein the structure is a component of a medical radiation machine having a target for interaction with the beam to generate radiation; and a first beam position monitor comprising a first electrode and a second electrode, the first electrode being mounted to a first side of the structure, the second electrode being mounted to a second side of the structure, the second side being opposite from the first side; wherein the first beam position monitor is located upstream with respect to the target.

An x-ray tube includes an electron emitter and a cathode cup having a recess that holds the electron emitter. The recess has a bottom surface, and a shield is positioned in the recess between the electron emitter and the bottom surface. The shield is configured to receive deposited sublimated emitter material and to maintain the sublimated emitter material away from the electron emitter.

An x-ray tube includes an electron emitter and a cathode cup having a recess that holds the electron emitter. The recess has a bottom surface, and a shield is positioned in the recess between the electron emitter and the bottom surface. The shield is configured to receive deposited sublimated emitter material and to maintain the sublimated emitter material away from the electron emitter.