| 摘要 |
PURPOSE:To reduce the heat loss in the axial direction caused by thermal conduction of an inner discharge tube, and improve laser efficiency, by installing a thermal conduction deteriorating part to decrease the thermal conduction in the axial direction of the inner discharge tube, on at least both end sides of the inner discharge tube which is inserted into a vacuum jacket, contains metal particles for producing metal vapor, and is arranged between electrodes. CONSTITUTION:The large diameter thick part 2A of an inner discharge tube 2 is enclosed by an atmospheric heat insulating layer 3. Thin parts 2B of said tube 2 are arranged on both end sides in the axial direction of the tube 2, and serve as thermal conduction deteriorating parts. The thin parts 2B are constituted of the groove bottom parts of ring type grooves formed on the outer peripheral parts on both end sides of the inner discharge tube 2. The heat generated by pulse discharge between electrodes in the atmosphere of discharge gas 14 in the inner discharge tube 2 is transferred to the inner discharge tube 2. In this case, the thermal conduction in the axial direction of the tube 2 is remarkably decreased by the thin part 2H. Further, since the large diameter thick part 2A of the tube 2 is surrounded by the atmospheric heat insulating layer 3, the heat loss in the axial direction caused by thermal conduction in the axial direction of the tube 2 is reduced, and laser efficiency is improved. |
