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Title: Development of a laser cleaning method for the first mirror surface of the charge exchange recombination spectroscopy diagnostics on ITER

Journal Article · · Physics of Atomic Nuclei
 [1]; ; ; ;  [2];  [1]
  1. State Research Center Troitsk Institute for Innovation and Fusion Research (TRINITI) (Russian Federation)
  2. National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation)

A set of optical diagnostics is expected for measuring the plasma characteristics in ITER. Optical elements located inside discharge chambers are exposed to an intense radiation load, sputtering due to collisions with energetic atoms formed in the charge transfer processes, and contamination due to recondensation of materials sputtered from different parts of the construction of the chamber. Removing the films of the sputtered materials from the mirrors with the aid of pulsed laser radiation is an efficient cleaning method enabling recovery of the optical properties of the mirrors. In this work, we studied the efficiency of removal of metal oxide films by pulsed radiation of a fiber laser. Optimization of the laser cleaning conditions was carried out on samples representing metal substrates polished with optical quality with deposition of films on them imitating the chemical composition and conditions expected in ITER. It is shown that, by a proper selection of modes of radiation exposure to the surface with a deposited film, it is feasible to restore the original high reflection characteristics of optical elements.

OSTI ID:
22471866
Journal Information:
Physics of Atomic Nuclei, Vol. 78, Issue 14; Other Information: Copyright (c) 2015 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7788
Country of Publication:
United States
Language:
English