| 摘要 |
PURPOSE:To increase lifetime of gas by sucking part of circulating gas from a gas flow pool near a preparatory ionization pin to purify it, and discharging purified gas between an electrode and a window along an optical axis. CONSTITUTION:A suction tube 2 is provided in a gas pool 1 of a preparatory ionization pin 4 of an impurity generator for deteriorating laser gas, and introduced to a purifier 6. The purifying gas to be returned to a main flow through the purifier 6 is driven by a centrifugal fan 7 installed coaxially with a gas circulating fan 10 in a pressure partition wall 12, and purified gas is circulated from the intermediate part 13 of a laser optical axis direction between a window glass or mirror 14 and a main discharge electrode 5. Thus, gas can be guided to the purified in a state that impurity concentration is high to enhance purifying efficiency and to remarkably increase gas lifetime. |
