| 摘要 |
PURPOSE:To reduce gas exchange time and gas consumption by raising the pressure of the gas in an oscillation tube to more than the atmospheric pressure at downtime, and at starting, by exhausting one kind of gas of a plurality of gases composing laser medium gas to partial pressure necessary for operation and injecting the other gases to the partial pressure necessary for operation. CONSTITUTION:A second control valve 13 is opened at downtime and N2 gas is injected in an oscillation tube 1. The gas pressure in the oscillation tube 1 is constantly monitored by a gas sensor 2 and when it attains 850 Torr, the second control valve 13 is closed. Since the pressure 850 Torr is higher than the usual atmospheric pressure, foreign material in the atmosphere is prevented from entering the oscillation tube 1 at downtime. Then at starting, N2 gas is exhausted to leave only 37.8 Torr that is the necessary partial pressure in the laser medium gas at operating. After that, a control valve 11 is opened to inject CO2 gas and He gas in the oscillation tube 1. When the gas pressure in the oscillation tube 1 reaches 120 Torr, the first control valve 11 is closed. CO2, N2, and He gases are involved in the gas thereby providing the specified pressure needed for oscillation. |
