| 摘要 |
PURPOSE:To remove carbon without opening or closing an apparatus and avoid a contamination in the apparatus due to dust, oil, moisture and the like in the air by filling a cleaning gas in a circulating path and removing carbon attached to an electrode while executing an electric discharge. CONSTITUTION:A laser gas composed of CO, O2, N2, He and the like is filled in a circulating path 1. Since the laser gas is circulated by a circulator 4 in a direction shown by an arrow in an oscillation operation and the temperature of the laser gas is raised by an electric discharge in a discharge portion 3, the laser gas is cooled by an indirect heat exchange with a low temperature refrigerant such as liquid nitrogen in a heat exchanger 5. When the discharge is executed between the electrodes 2 of the discharge portion 3 and a laser is outputted, CO gas in the laser gas generates carbon in part, which is attached to the electrodes 2. When the carbon is attached to the electrodes 2, the electric discharge in the discharge portion 3 is stopped once, the laser gas is exhausted from the circulating path 1 and a cleaning gas is supplied to the circulating passage 1 from a cleaning gas supply 10. Thereafter, by executing the electric discharge in the discharge portion 3, the carbon reacts with oxygen in the cleaning gas to be changed to CO gas and removed from the electrodes 2. |
