PURPOSE: To improve the electric-power resistant capacity and the thermal conductivity of an electron tube and reduce the gas-discharge rate at high temperature of said electron tube by preparing the attenuators, which are installed in a vacuum area, form high-density ceramics which contains a specified amount of SiC with a specified relative density.
CONSTITUTION: Wedge-like high-frequency attenuators 13 and 14 provided at a circuit-dividing part, are stuck to the surfaces of a circuit-shielding plate 25 which has an electron-beam passing hole 22 and has no connection holes. The attenuators 13 and 14 are prepared from ceramics which consists of over 85wt% of SiC and at least one matter chosen from among the group consisting of the simple substances and the chemical compounds of C, B, Be, Al, Ti, W, Nb, Mo, Zr, Va and Ta. As a result, the electric-power resistant capacity and the thermal conductivity of the electron tube can be increased, and the gas-discharge rate at high temperature can be decreased.
MATSUNAKA MASAFUMI
SUGIYAMA TSUTOMU
KYOCERA CORP
TOKYO SHIBAURA ELECTRIC CO