| 摘要 |
PURPOSE:To enable early detection of water leakage by a method wherein the increase in water amount due to water leakage of cooling water supply pipes and the like in a discharge gas container is detected by a dew-point sensor, thus driving an abnormal operation means. CONSTITUTION:Normally the dew point in a casing 10 is kept at -40--60 deg.C; however, when a very small amount of water leaks out of the joint of e.g. a high voltage electrode cooling water supply pipe 9, this water amount mixes in the laser gas, and the water amount of the laser gas increases more than a predetermined proper amount of water, resulting in a rapid decrease in the due point. At this time, the dew-point sensor 11 detects this phenomenon, and a control circuit 12 sets in action and releases abnormal alarm; thus, the abnormality due to water leakage can be early detected. |
