| 摘要 |
<p>PURPOSE:To produce a large quantity of electric field radiating cathodes excellent in directivity and current stability at a uniform standard by coating them with metals such as Ti, Zr, Hf without using a W monocrystal. CONSTITUTION:When a sharp needle is produced by polishing under an electric field a prism cut out in a strip shape at an angle of 45 deg. to the rolling direction from a W polycrystal plate (normal W plate) rolled to a thickness of 1mm. or less, the electric field radiation from this sharp needle indicates an electric field radiation pattern exactly the same as that of a polycrystal sharp needle in the direction of (100). The lower limit of the thickness is about 30mum or more from the standpoint of strength, and the actual thickness of the sharp needle is within a range of 0.1-0.5mm. due to the working problem. A cathode figure including a filament and the sharp needle in one body is photo-etched in the 45 deg. direction. A portion to become a frame is formed for each line and a non-etched portion is slightly formed with a filament end surface, and each cathode is made to be held by the W plate after etching. Metals such as Ti, Hf, Zr are deposited by spattering or evaporation from both sides. The tip is finely sharpened by electric field polishing.</p> |
