| 摘要 |
PURPOSE:To exhaust moisture or the like stuck to the casing inner wall at the bake-out time in large quantities and in a short time by providing a casing forming a gas laser generating part with not less than two open hole parts for exhaustion. CONSTITUTION:A gas laser casing 1 is provided with an open hole part 1B apart from an open hole part for exhaustion 1A which is a larger diameter than that of 1A. An exhaust pipe 6 formed having the same outer diameter with that of the open hole part is connected thereto, and on its half way an exhaust valve 7 and an exhaust pump 8 are provided in order. Consequently, a pump having larger exhaust capacity than that of an exhaust device for gas exchange can be connected to the open hole part 1B. Accordingly, a high- vacuum state can be easily obtained by exhausting gas inside the casing 1 by simultaneously using two exhaust devices at the bake-out time immediately after assembly so as to remove moisture or the like stuck to the inner wall of the casing 1. |
