| 摘要 |
<p>PURPOSE:To attempt remarkable reduction of time required from start of current flow heating until achievement of thermally steady status, by applying some material of good heat conductivity to a supporter which holds cathode section. CONSTITUTION:Provide, inside of electron gun housing 11, some supporter, for instance, high voltage porcelain insulator 12 which should be made from substance of high heat conductivity such as BeO, BN, MgO etc. Utilize this high voltage porcelain insulator which supports cathode section holding LaB6 cathode 14 by means of heat generating block 13 made of pyrolitic graphite etc. and leads out the lead wire of heat generating block 13 out of housing 11 via high voltage cable 15, while keeping this status as it is. Around heat generating block 13 and cathode section composed of cathode 14, provide wenelt 16 which forms an aperture at the section corresponding to cathode 14. By means of this contrivance, it is possible to reduce remarkably the time required from start of current flow heating until achievement of thermally steady status.</p> |
