High-power, room-temperature operated CO laser

The objectives of this study are to achieve high-power, efficient operation of a room-temperature CO laser and to collect data for designing the CO laser system for nuclear reactor decommissioning. The influence of the H20 concentration in the laser gas on the output performance was investigated, and it was found that the H,O concentration should be kept as low as possible (less than 260 ppm) to obtain stable, high-power outputs. To improve output performance, the rf frequency was increased from 13.56 MHz to 27.12 MHz. The output power for the 27.12 MHz excitation was increased by 10 to 20% compared with that for the 13.56 MHz excitation. The laser output was scaled by extending the discharge tube inner diameter from 19 mm to 30 mm. By optimizing the air gap length and the curvature radius of the outer metallic electrode, the operating gas conditions, and the reflectivity of the output coupler, a maximum output of 830 W was obtained at a laser efficiency of 12.2 % with adding neither Kr nor Xe. The addition of Kr was more effective for increasing the output than the addition ofXe. A maximum output of9IO W was obtained at a laser efficiency of 14.8 % with Kr addition, and a maximum output of8IO W was obtained at a laser efficiency of I 6.2 % with Xe addition