| 摘要 |
PURPOSE:To eliminate the use of a beryllia porcelain material, which is expensive and is difficult to be obtained, by forming a plasma small tube by graphite, holding the graphite by a metal and using the metal as one part of a surrounding instrument and a radiator. CONSTITUTION:The plasma small tube 3 consisting of a graphite cylinder with a small outside diameter is supported by metals 9, 9', 9'' forming one part of the vacuum surrounding instrument connected to hard glass 8, 8' shaping the surrounding instrument, and insulated by the glass 8, 8' at a predetermined interval. Radiation fins 5 are mounted outside the vacuum of the metal 9, and forcedly cooled by air by means of a cooling fan. A plurality of holes 10 with small diameters are bored to one part of the section 9' in the vacuum of the metal, and fill the role of gas return paths. Accordingly, the graphite easy to be obtained can be used for the plasma small tube, the tube is forcedly cooled by air by means of the radiation fins, and an external return path is unnecessitated. |
