| 摘要 |
The problems of maintaining proper alignment of the mirrors of an excimer laser in the face of thermal and pressure distortions of the ends of the laser vessel and when replacing the mirrors after removal for cleaning are overcome by mounting the mirrors on a separate, fixed supporting frame that is not influenced by movement of the vessel ends. The mounts nevertheless serve to connect the mirrors to the respective vessel ends so as to seal the pressurized gases in the vessel interior from the exterior. This sealing connection is a yielding one that permits relative movement between the vessel ends and the mirrors and hence avoids affecting the alignment of the mirrors. The mounts also include provision for ensuring that, after removal and replacement, wedge shaped mirrors are correctly realigned in respect of rotation about the axis of the laser beam, and that the mirrors can be replaced with their reference surfaces in exactly the original plane.
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