Measurements of the angle-dependent reflectivity of plasma-facing components and assessment of the impact on the estimations of coverage of the IVVS measurements of the ITER VV

Abstract The In-Vessel Viewing System (IVVS) is a metrology instrument designed for deployment inside the ITER Vacuum Vessel (VV) to assess any damage, erosion or displacements of the Plasma-Facing Components (PFCs) through the lifetime of the ITER experiment. The latest developments of the IVVS have identified the Incidence-Angle-Dependent Reflectivity (IADR) of the PFCs to be critical to the assessment of the coverage of the IVVS within the VV. Some ITER PFC prototypes have now been manufactured and a specific instrument has been developed to measure their IADR on site, in an IVVS-like geometry with 100 dB dynamic range. This work presents the first measurements of manufactured ITER PFCs’ IADR together with an assessment of the impact of the IADR on the effective coverage of the viewing channel of the IVVS operating through amplitude-modulated lidar.