| 摘要 |
PURPOSE:To efficiently suppress temperature rise of a permanent magnet by a method wherein a radiating fin extending between an anode part and a permanent magnet is formed and both sides of a frame-shaped heel piece of this radiating fin are provided with number of salient edges separated by long slits in the direction crossing the surface, further these salient edges are provided with twisted parts. CONSTITUTION:A metal body 18 consisting of aluminium or its alloy has a cylindrical part 18a facing an inner circumferential surface of a ring permanent magnet 5 and a flange part 18b forming a radiating fin, further the cylindrical part 18a fits in a cylindrical salient part of a sealding case 9. The flange part 18b extending between an anode part of a magnetron 1 and a permanent magnet 5 has a larger outer diameter than the outer diameter of the permanent magnet 5 and has numbers of salient edges 18c on the side of the opening surface of a frame-shaped heel piece 8 while being separated by long slits in the direction crossing this opening surface and each salient edge 18c has twisted part formed by twisting processing by about 90 deg.. Thereby, temperature rise of the permanent magnet 5 can be efficiently suppressed.
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