Renewal of the interfero-polarimeter diagnostic for WEST

Abstract In the frame of the WEST tokamak upgrade project, the Tore Supra combined interferometer-polarimeter diagnostic has been modified to fit the geometry and constraints induced by the implementation of divertor coils in the vacuum vessel. For a good spatial resolution of the plasma, as the vertical ports are now partially obstructed, 8 infrared beams go through a common horizontal port and are retro-reflected on an inner panel and 2 vertical port retro-reflected channels, with specific vacuum mirrors close to the divertor, could be implemented to diagnose the edge plasma. The electronics and the data acquisition have also been renewed to improve the reliability and precision of the measurements. Novel digital electronics with embedded interferometric and polarimetric algorithms produce 1 ms data outputs for real time control. The diagnostic has routinely been operated during the first WEST campaigns. In this article, we detail the new arrangement and discuss the first results with plasma.