Electron power tube cooled by circulation of a fluid

A power electron tube comprising:

• substantially coaxial electrodes including an anode having an interior, hermetically closed space subject to a vacuum, the anode being positioned external to a grid surrounding a cathode;
• a substantially circular anode connection part for external electrical connection of the anode, the anode connection part having first and second ends and first and second main faces, the first end of the anode connection part being connected to the anode and a portion of the first main face of the anode connection part being sealed, at a sealing zone, to one end of an insulating tie having another end thereof joined to one of the coaxial electrodes different from the anode, the anode connection part and the insulating tie closing a portion of the interior, hermetically closed space of the anode;
• and
• a cooler providing forced circulation of a cooling fluid and formed by substantially coaxial inner and outer jackets mounted around the anode and defining a closed chamber, the anode connection part being brazed at the second end thereof to a part which is solidly joined to the outer jacket, the anode connection part closing a portion of the closed chamber of the cooler and the cooling fluid circulating along at least a portion of the second main face of the anode connection part adjacent to the insulating tie to cool the sealing zone between the insulating tie and the anode connection part.