Conceptual design of optical path related elements in the port plug of ITER core lidar diagnostic

The present paper describes the engineering conceptual design of the optical labyrinth and the first and second mirror mounts of the ITER core LIDAR diagnostics. The optical labyrinth, being in a very sensitive location close and open to the plasma, has been examined carefully to be able to provide different solutions satisfying the needs of the diagnostics. Therefore the conceptual design considered the covering of the light path, the integration of the labyrinth into the port plug as well as the shape, color and material of the labyrinth inner surface to be able to handle the undesirable phenomena of scattered light and sputtered particles reaching the mirroring surface. Nevertheless, cooling/ baking has also been considered and appropriate solutions presented.