According to one embodiment, a klystron includes a plurality of cavity resonators arranged next to each other on a coaxial line. The cavity resonators each comprise a cylindrical body, one and another drift tubes provided on respective sides of respective ends of the cylindrical body, one and another support and a space adjustment means which adjusts the space between the one and the other drift tubes. The cylindrical body comprises a projection projecting from one end surface parallel to the axial line, and the one support is provided to abut on the projection, and the space adjustment means presses the one support toward the projection and adjusts the space between the one and the other drift tubes by plastically deforming the projection.

According to one embodiment, a klystron includes a plurality of cavity resonators arranged next to each other on a coaxial line. The cavity resonators each comprise a cylindrical body, one and another drift tubes provided on respective sides of respective ends of the cylindrical body, one and another support and a space adjustment means which adjusts the space between the one and the other drift tubes. The cylindrical body comprises a projection projecting from one end surface parallel to the axial line, and the one support is provided to abut on the projection, and the space adjustment means presses the one support toward the projection and adjusts the space between the one and the other drift tubes by plastically deforming the projection.

An electron beam 3D printing machine, comprising a chamber for generating and accelerating an electron beam and an operating chamber in which a metal powder is melted, with the consequent production of a three-dimensional product. The chamber for generating and accelerating an electron beam houses means for generating an electron beam and means for accelerating the generated electron beam, while the operating chamber houses at least one platform for depositing the metal powder, metal powder handling means and electron beam deflection means. The accelerator means for the generated electron beam comprise a series of resonant cavities fed with an alternating signal.

An electron beam 3D printing machine, comprising a chamber for generating and accelerating an electron beam and an operating chamber in which a metal powder is melted, with the consequent production of a three-dimensional product. The chamber for generating and accelerating an electron beam houses means for generating an electron beam and means for accelerating the generated electron beam, while the operating chamber houses at least one platform for depositing the metal powder, metal powder handling means and electron beam deflection means. The accelerator means for the generated electron beam comprise a series of resonant cavities fed with an alternating signal.

An electron gun comprising a cathode having an electron emitting surface and whose planar shape is circular, a heater to increase the temperature of the cathode, and an anode to apply a positive electric potential relative to the cathode to extract electrons in a predetermined direction is provided. The cathode comprises a through hole at a central portion thereof along a central axis of the cathode, and either the cathode comprises a no-emitting layer at at least one of an opening edge on the electron emitting surface side of the through hole and an inner surface of the through hole, or the opening edge on the electron emitting surface side of the through hole is a chamfered C surface or a chamfered R surface.

A liquid metal or spiral groove bearing structure for an x-ray tube and associated process for manufacturing the bearing structure is provided in which journal bearing sleeve is formed with a number of structures thereon that function to dissipate heat transmitted to the sleeve during operation of the bearing assembly within the x-ray tube to minimize thermal deformation of the sleeve, thereby minimizing gap size alteration within the bearing assembly. The structures formed within the sleeve are slots disposed within the section of the sleeve in which the highest temperature gradients develop. The slots enable an increase in thermal conductance away from the sleeve while minimizing the stresses created from the deformation of the portion(s) of the sleeve between the slots.

An electron gun comprising a cathode having an electron emitting surface and whose planar shape is circular, a heater to increase the temperature of the cathode, and an anode to apply a positive electric potential relative to the cathode to extract electrons in a predetermined direction is provided. The cathode comprises a through hole at a central portion thereof along a central axis of the cathode, and either the cathode comprises a no-emitting layer at at least one of an opening edge on the electron emitting surface side of the through hole and an inner surface of the through hole, or the opening edge on the electron emitting surface side of the through hole is a chamfered C surface or a chamfered R surface.

Some embodiments include a resonant converter klystron driver. A resonant converter klystron driver, for example, may include an input power supply; a full-bridge circuit coupled with the input power supply; a resonant circuit coupled with the full-bridge; a step-up transformer coupled with the resonant circuit; a rectifier coupled with a step-up transformer; a filter stage coupled with the rectifier; and an output coupled with the filter stage. In some embodiments, the output could be coupled with a klystron.

Some embodiments include a resonant converter klystron driver. A resonant converter klystron driver, for example, may include an input power supply; a full-bridge circuit coupled with the input power supply; a resonant circuit coupled with the full-bridge; a step-up transformer coupled with the resonant circuit; a rectifier coupled with a step-up transformer; a filter stage coupled with the rectifier; and an output coupled with the filter stage. In some embodiments, the output could be coupled with a klystron.

According to one embodiment, a klystron includes an electron gun unit, a plurality of resonant cavities, a collector, and a plurality of drift tubes. The resonant cavities include an input cavity, a plurality of intermediate cavities, and an output cavity, positioned sequentially along the traveling direction of electrons from the electron gun unit. The intermediate cavities include a plurality of second harmonic cavities. The collector captures the electrons that have passed through the resonant cavities. The drift tubes are provided between the electron gun unit and the input cavity, between the resonant cavities, and between the output cavity and the collector.