| 摘要 |
PURPOSE:To suppress a heat transfer to the side of a high frequency acting part and prevent fluctuations of operating characteristics by forming an insulating supporter, arranged between a collector-supporting plate and a collector electrode which is located just on the downstream side, by the use of a material whose thermal conductivity is low compared with the insulating supporter mutually arranged between collector electrodes which are located on the downstream side. CONSTITUTION:A ring-shaped insulating supporter 37, arranged between a combination of a collector-supporting plate 26, which has both the same electrical potential and the slight heat-transferred continuity to a high frequency acting part 11, and a heat shield 27, and the first collector electrode 28 which is located just on the beam downstream side, is composed of ceramics having low thermal conductivity and high electrical resistance such as alumina-zircon, steatite, forsterite, and mullite ceramics. Therefore, heat conductive from the collector electrode side to high frequency acting part 11 can be suppressed more greatly. |
