Application of optical techniques for in situ analysis of plasma facing carbon tiles

Optical absorption/emission spectroscopy is considered to be used for in situ characterization of plasma facing carbon tiles and quantitative evaluation of tritium. In this paper we have applied ex situ laser Raman spectroscopy for carbon tiles used as first wall and divertor in JT-60 exposed to HH discharge plasma to verify the applicability of the technique. The analysis shows that the micro-structure of the carbon tile surfaces is modified in a similar way like damaging by energetic ion irradiation and that one can get information of how graphite structures are damaged by plasma exposure or what kind of structures the redeposited carbon obtains.