Development of the UV and visible impurity influx monitor (divertor) for ITER

Iwamae, Atsushi; Ogawa, Hiroaki; Sugie, Tatsuo; Kasai, Satoshi*; Kusama, Yoshinori

We are developing a spectroscopic diagnostics system in wavelength region of 2001000 nm for monitoring ITER divertor plasmas, such as the influxes of impurity elements, the position of the ionization front, the electron temperature and density. An equivalent size prototype of the optical components for the upper port spectroscopic diagnostics system has been fabricated and assembled into the system to estimate quantitative light throughput. Line intensities of helium ash and carbon ions are estimated with collisional radiative model. Measured signal intensity is estimated with the prototype spectral throughput and the estimated line radiance. The reflection of the plasma facing materials of divertor, tungsten and carbon fiber composite are measured. The tungsten reflection is 23% at 656 nm. There is anisotropic aspect of the reflection from the tungsten divertor material surface.