摘要 |
An indirectly heated cathode includes a cathode sleeve ( 2 ) housing a heater ( 1 ), a caplike base ( 3 ) attached onto the cathode sleeve ( 2 ), and an electron emitter layer ( 4 ) formed on a surface of the base ( 3 ). The cathode sleeve ( 2 ) is made of a metal material that contains nickel and chromium as main components and further contains at least silicon, aluminum, cerium, and lanthanum. According to this construction, the cathode sleeve ( 2 ) is kept from heat deformation. Hence a reliable indirectly heated cathode which suppresses variations in cutoff voltage can be realized.
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