Application of optical reflectivity measurements to diagnostics for plasma facing materials

The detectable change of the reflectivity was observed and the level of the degradation depended on the location, exposure period and employing wavelength. Microstructure observation of the mirror surface revealed that the behavior of the reflectivity change correlated closely with the ion-induced damages and the depositions thickness in the vicinity of the sample surface. Thus, the optical reflectivity measurement is considered to be a possible method for convenient in-situ diagnostics for PFMs.