| 摘要 |
PURPOSE:To prevent the infiltration of atmosphere into a laser oscillator by a method wherein the pressure in the laser oscillator is made equal to the atmospheric pressure or over it by supplying a laser gas into the laser oscillator at a down time of the laser oscillator. CONSTITUTION:When the operation of the oscillator 25 is suspended, an electromagnetic valve 24 is put in a state II (closed) at the same time with the stop of a vacuum pump 26, an electromagnetic valve 29 is put in a state I (opened), and thus the laser gas is supplied into the oscillator 25. Thereby, the infiltration of the atmosphere into the oscillator 25 is prevented by making the pressure in the oscillator 25 equal to the atmospheric pressure or over it. Since the laser gas has the purity of normally approximately 99 or 95%, the infiltration of an impurity becomes extremely small. As a result, the lifetime of mirrors and electrodes in the oscillator 25 or the discharge characteristics can be largely improved. |
