| 摘要 |
PURPOSE:To stabilize the energy of a laser without reducing the energy even in a long period shooting, and to supply the laser by providing a rare gas inlet hole at a position near an optical member, a halogen gas inlet hole at a position isolated from the member, and further separately a mixture gas discharge hole. CONSTITUTION:Rare gas blown from an inlet hole 4 is scattered around to cover a window 3. Halogen (F2) gas is so introduced from a hole 5 formed at a position isolated from a window member through a control valve 9 as to maintain concentration corresponding to the rare gas blowing amount, and other rare gas (Kr) is introduced from a hole 6 formed at a suitable position. Since the halogen gas has a plenty of activity, when it is introduced to the vicinity of the member, it is easily deposited on the member by means of optochemical reaction with a laser light irrespective of the sole gas or the mixture gas with the rare gas. Accordingly, it is important to introduced it at the position isolated from the member. The rare gas and the halogen gas are made uniform by auxiliary means such as mutual diffusion and fan at its next stage. Another discharge hole 7 is provided to maintain the pressure in a vessel constant, and it is discharged through a control valve 10. |
