Ray tracing study of ITER in-vessel lighting system

In-vessel lighting system is being developed for ITER. The diagnostic system is for inspecting and detecting eventual damages and defects of in-vessel components between discharges by illuminating the vacuum vessel with light sources. In this work, feasibility study of the in-vessel lighting system is performed using a ray tracing simulation. We installed sources and detectors in a ray tracing model using the field of views of wide-angle viewing systems and calculated the radiance profiles at detectors for different wall reflection scenarios. It was found that the wall is uniformly illuminated when the wall has a diffuse reflectance while the specular case has more brightness. We will discuss feasibility of the diagnostics system based on expected signal and noise levels.