| 摘要 |
<p>PURPOSE:To obtain high brightness and to take out large current stably, by adsorbing a metal selected from Zr, Hf groups on an electron emissive surface and operating its needle cathode with temperature of specific brightness. CONSTITUTION:One metal selected from Zr and Hf groups is adsorbed through oxygen with depth shorter than a unit atom layer on the surface of tip region of needle cathode made of single crystal metal of W or Mo having crystal axis of (100) where at least the electron is mainly emitted, then covered with an adsorption layer. Consequently the emission angle distribution of electron is reduced thereby large current can be obtained. Moreover when heating the electrode within the luminance temperature of 1,000-1,110 deg.K, the stability of current can be improved.</p> |
