| 摘要 |
PROBLEM TO BE SOLVED: To obtain high-luminance, high-emittance beams exceeding a Langmuir limit with a plane drawer electrode electron gun equipped with a plane cathode, Wehnelt, and a drawer electrode or an anode. SOLUTION: A cathode 1 of a circular plane, a drawer electrode or an anode 3 shaped as a part of a spherical surface, and a Wehnelt electrode 2 of a frustum of a cone shape are provided. A virtual cone crossing a light axis on an outer periphery of the cathode and a drawer electrode position and a virtual frustum of a cone with an angle difference of 67.5°are assumed, outside which, the Wehnelt electrode is provided. Especially, a high luminance is obtained in a simulation with a cathode radius of 10μmR to 960μmR. Further, in the electron gun so controlled that electron beams emitted from the cathode of a photocathode monotonously decrease beam radii from the cathode to the drawer electrode, and form a crossover toward the rear of the drawer electrode, beams with high luminance and a small energy width can be utilized. COPYRIGHT: (C)2008,JPO&INPIT
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