A magnet system comprising: a supplied magnetic field producer configured for creating a supplied magnetic field (SMF) or a supplied radial electric field producer configured for creating a supplied radial electric field (SREF); and an electron gun positioned so as to fire electrons into the SMF or the SREF such that the electrons fired from the electron gun form an electron coil, wherein the electron coil creates a self-generated magnetic field (SGMF), wherein the electron coil is formed in a vacuum.

A laminated body is provided in a circumferential shape with a gap formed in a part of a circumferential direction on a semiconductor layer. In the laminated body, a first insulating layer, a gate layer, a second insulating layer, and a drain layer are layered in this order from the semiconductor layer side. An impurity diffusion layer is formed on a surface of the semiconductor layer, and a backside electrode on a backside surface. The impurity diffusion layer extends from a position in contact with side walls in a channel space to an outside of the laminated body through a region corresponding to the gap on the surface of the semiconductor layer. A portion of the impurity diffusion layer beyond the laminated body is a contact region to which a wiring for applying a predetermined voltage is connected. A cover layer made of an insulating material is formed in an upper portion and a periphery of the annular portion including the laminated body and the gap.

An apparatus includes: a structure having a lumen for accommodating a 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.

A vacuum tube for amplifier circuit includes: a light incidence window that transmits signal light; a photoelectric conversion unit that converts the signal light transmitted through the light incidence window into photoelectrons; an output unit that has an anode, on which the photoelectrons are incident, and outputs a signal corresponding to the incident photoelectrons; and a grid electrode that is disposed in a path of the photoelectrons from the photoelectric conversion unit to the anode and controls the amount of photoelectrons incident on the anode.

A vacuum transistor includes a substrate and a first terminal formed on the substrate. A piezoelectric element has a second terminal formed on the piezoelectric element, wherein the piezoelectric element is provided over the first terminal to provide a gap between the first terminal and the second terminal. The gap is adjusted in accordance with an electrical field on the piezoelectric element.

A vacuum transistor includes a substrate and a first terminal formed on the substrate. A piezoelectric element has a second terminal formed on the piezoelectric element, wherein the piezoelectric element is provided over the first terminal to provide a gap between the first terminal and the second terminal. The gap is adjusted in accordance with an electrical field on the piezoelectric element.

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.

A light intensifier includes a semiconductor structure to multiply electrons and block stray particles. A thin gain substrate layer includes an electron multiplier region that is doped to generate a plurality of electrons for each electron that impinges on an input surface of the gain substrate layer and blocking structures that are doped to direct the plurality of electrons towards emission areas of an emission surface of the gain substrate layer. Respective ribs of a first plurality of ribs on the input surface of the gain substrate layer are vertically aligned with respective blocking structures, and respective blocking structures are vertically aligned with respective ribs of a second plurality of ribs at the emission surface. This alignment directs electrons along a path through the gain substrate layer to reduce noise. The support ribs provide mechanical strength to the gain substrate layer, improving robustness of the light intensifier while minimizing noise.

A light intensifier includes a semiconductor structure to multiply electrons and block stray particles. A thin gain substrate layer includes an electron multiplier region that is doped to generate a plurality of electrons for each electron that impinges on an input surface of the gain substrate layer and blocking structures that are doped to direct the plurality of electrons towards emission areas of an emission surface of the gain substrate layer. Respective ribs of a first plurality of ribs on the input surface of the gain substrate layer are vertically aligned with respective blocking structures, and respective blocking structures are vertically aligned with respective ribs of a second plurality of ribs at the emission surface. This alignment directs electrons along a path through the gain substrate layer to reduce noise. The support ribs provide mechanical strength to the gain substrate layer, improving robustness of the light intensifier while minimizing noise.