| 摘要 |
<p>PURPOSE:To position a metallic block for a second electrode and an insulating vessel easily while improving safety by forming a groove receiving a lead for a control electrode and a mark for positioning to the metallic block for the second electrode. CONSTITUTION:A mark 17 for positioning projected to the outer surface of the flange 15 of a metallic block 14 for a second electrode up to an inner end from an outer end and a reference positioning mark 18 consisting of a projection shaped to the outer surface of the flange 2 of an insulating vessel 1 are positioned, an opening section at the other end of the insulating vessel 1 is sealed by the metallic block 14 for the second electrode, and a lead 12 for a control electrode is received completely into a groove 16a. The groove 16a and the lead 12 for the control electrode are displaced and the flange 15 and the flange 2 are not welded and joined because both flanges 15 and 2 can be welded and joined while making sure the mark 17 for positioning and the reference positioning mark 18.</p> |
