| 摘要 |
An apparatus for an electron gun includes a one piece thermionic electron source that extends in a longitudinal direction and has opposite end portions, an aperture disposed therebetween, and two longitudinal portions that extend in the longitudinal direction and are spaced apart from one another by the aperture and rigidly joined together by the opposite end portions. The thermionic electron source is less susceptible to ion bombardment and therefore has a longer operating life than previous ribbon type electron sources. Further, because the electron source is one piece, it does not require support and relative positioning of multiple emitters such as that required by an electron source having two separate and parallel emitters.
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