A microwave tube comprises an electron gun that emits an electron beam; a magnetic circuit that focuses the electron beam emitted from the electron gun; a collector that captures the electron beam that has passed through the magnetic circuit; a high frequency circuit that is spirally arranged around the electron beam focused by the magnetic circuit and that transmits a high frequency; and a magnetic body part arranged around the electron gun so as to be movable in an emission direction of the electron beam, wherein a high frequency output from the high frequency circuit is controlled to be constant by moving the magnetic body part in an emission direction of the electron beam.

A microwave tube comprises an electron gun that emits an electron beam; a magnetic circuit that focuses the electron beam emitted from the electron gun; a collector that captures the electron beam that has passed through the magnetic circuit; a high frequency circuit that is spirally arranged around the electron beam focused by the magnetic circuit and that transmits a high frequency; and a magnetic body part arranged around the electron gun so as to be movable in an emission direction of the electron beam, wherein a high frequency output from the high frequency circuit is controlled to be constant by moving the magnetic body part in an emission direction of the electron beam.

A microwave source used in the radiotherapy device can be provided. The microwave source may include an anode block and one or more cathodes. The cathode of the microwave source may include a cathode support element having a plurality of slots. The plurality of slots can be axially around a circumference of the cathode support element. The microwave source may include a cathode heater including at least one filament. A first part of the at least one filament may be wound around the cathode support element along a first direction and received by a first portion of the plurality of slots, and a second part of the at least one filament may be wound around the cathode support element along a second direction and received by a second portion of the plurality of slots.

A microwave tube includes an electron gun that emits an electron beam; a magnetic circuit that focuses the electron beam emitted from the electron gun; a collector that captures the electron beam that has passed through the magnetic circuit; a high frequency circuit that is spirally arranged around the electron beam focused by the magnetic circuit and that transmits a high frequency; and a magnetic body part arranged around the electron gun so as to be movable in an emission direction of the electron beam. A high frequency output from the high frequency circuit is controlled to be constant by moving the magnetic body part in an emission direction of the electron beam.

A microwave tube includes an electron gun that emits an electron beam; a magnetic circuit that focuses the electron beam emitted from the electron gun; a collector that captures the electron beam that has passed through the magnetic circuit; a high frequency circuit that is spirally arranged around the electron beam focused by the magnetic circuit and that transmits a high frequency; and a magnetic body part arranged around the electron gun so as to be movable in an emission direction of the electron beam. A high frequency output from the high frequency circuit is controlled to be constant by moving the magnetic body part in an emission direction of the electron beam.

A travelling-wave tube comprising a helix joined by posts to a vacuum chamber, each post made of electrically insulating material being covered by an electrically conductive material, of electrical conductivity comprised between 1000 and 100000 S.Math.m−1, over a portion of the post extending from the end of the post joined to the helix to the end of the post joined to the vacuum chamber and corresponding to a height comprised between 10% and 50% of the post.

A travelling-wave tube comprising a helix joined by posts to a vacuum chamber, each post made of electrically insulating material being covered by an electrically conductive material, of electrical conductivity comprised between 1000 and 100000 S.Math.m−1, over a portion of the post extending from the end of the post joined to the helix to the end of the post joined to the vacuum chamber and corresponding to a height comprised between 10% and 50% of the post.

The objective of the invention is to provide a microwave tube, or the like, wherein gas adsorption action of a getter may be satisfactorily performed independently from a microwave amplification operation. In order to solve this problem, this microwave electron tube comprises: a helix wherein a microwave may progress oriented from an input section to an output section within a helical tube; an electron gun emitting an electron flow oriented toward the helix; a focusing device causing the electron flow to traverse the vicinity of the helix in the direction of a collector; the collector absorbing the electron flow; and a getter having a heater insulated from the cathode provided in the electron gun.

The objective of the invention is to provide a microwave tube, or the like, wherein gas adsorption action of a getter may be satisfactorily performed independently from a microwave amplification operation. In order to solve this problem, this microwave electron tube comprises: a helix wherein a microwave may progress oriented from an input section to an output section within a helical tube; an electron gun emitting an electron flow oriented toward the helix; a focusing device causing the electron flow to traverse the vicinity of the helix in the direction of a collector; the collector absorbing the electron flow; and a getter having a heater insulated from the cathode provided in the electron gun.

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.