| 摘要 |
PURPOSE:To stably support the main portion of cathode by forming a conductive end board for brazing both ends of the main portion of cathode in accordance with the shape of both ends of the main portion of cathode. CONSTITUTION:The main portion of cathode 12 composed of thorium tungsten or the like while formed in spiral is supported between a conductive end board 10 electrically connected with a lead rod 13 and a conductive end board 11 fitted with a pipe-shaped lead member 14. Ring grooves 10a, 11a to be contacted with entire circumference of the main portion of cathode 12 are formed on said conductive end boards 10, 11 where both ends of the main portion of cathode 12 are fitted in the grooves 10a, 11a and brazed. Consequently the main portion of cathode is supported reliably by the conductive end board thereby the brazing work is facilitated. |
