| 摘要 |
PURPOSE:To prevent an undesired film from forming on the inner surface of a light incident window of a reaction vessel by blowing inert gas to the inner surface of the window, thereby preventing stock gas which contributes to the accumulation from contacting with the inner surface of the window. CONSTITUTION:A gas nozzle 17 for preventing the cloud of a light incident window is provided on the inner surface of a light incident window 12 of a reaction vessel 11. Inactive rare gas such as hydrogen or halogen is supplied to the nozzle 17. The nozzle 17 is formed of a stainless steel pipe, and a plurality of gas injection holes are formed toward the window 12 at the pipe. Thus, inactive gas is blown to the inner surface of the window 12 of the vessel 11, thereby eliminating the stock gas which contributes to the accumulation of the film on the inner surface of the window 12. Then, no undesired film is formed on the inner surface of the window 12. |
