Abstract: An alumina-ceramic-based electrical insulator, to a method for producing the insulator, and to a vacuum tube includes the insulator. The electrical insulator is for insulating two electrodes of a vacuum tube through which a charged particle beam flows, the electrical insulator being formed of an alumina-based ceramic. The ceramic comprises a vitreous phase of between 2% and 8% by weight into which at least one metal oxide is diffused from a face of the electrical insulator.

Abstract: An alumina-ceramic-based electrical insulator, to a method for producing the insulator, and to a vacuum tube includes the insulator. The electrical insulator is for insulating two electrodes of a vacuum tube through which a charged particle beam flows, the electrical insulator being formed of an alumina-based ceramic. The ceramic comprises a vitreous phase of between 2% and 8% by weight into which at least one metal oxide is diffused from a face of the electrical insulator.

Abstract: A radiation source includes a vacuum chamber, means for injecting an optical wave, a cold source for emitting electrons, a power supply, an anode for emitting X-rays, and at least one window through which the X-rays exit. A light source delivers the optical wave, and the cold source includes at least one substrate with a conducting surface and is subjected to an electric field. The cold further includes a photoconductive element in which the current is controlled approximately linearly by the illumination and at least one electron-emitting element, the photoconductive element electrically connected in series between an emitting element and a conducting surface. Current photogenerated in the photoconductive device is equal to that emitted by the emitter or the group of emitters with which it is associated, and the emitted stream of X-rays is approximately linearly dependent on the illumination.

Abstract: A radiation source includes a vacuum chamber, means for injecting an optical wave, a cold source for emitting electrons, a power supply, an anode for emitting X-rays, and at least one window through which the X-rays exit. A light source delivers the optical wave, and the cold source includes at least one substrate with a conducting surface and is subjected to an electric field. The cold further includes a photoconductive element in which the current is controlled approximately linearly by the illumination and at least one electron-emitting element, the photoconductive element electrically connected in series between an emitting element and a conducting surface. Current photogenerated in the photoconductive device is equal to that emitted by the emitter or the group of emitters with which it is associated, and the emitted stream of X-rays is approximately linearly dependent on the illumination.