Remote infrared view of JET divertor compatible with D-T operations

A remote viewing system located outside the biological shield wall to image the divertor region in JET is presented here. This paper focuses on the optical and mechanical designs of the installation of a line of sight which is capable of imaging the divertor over an optical distance of approximately 31 m. In addition, it includes the experience obtained during operations and it demonstrates its successful performance. This line of sight was the second viewing system used during the D-T campaign and it follows from the paper dedicated to the remote wide angle view line of sight which is also compatible with D-T operations and includes common elements to the construction of the two lines of sight. The main novel feature is the design in house of two glass reinforced plastic kinematic mounts standing vertically to each accommodate a mirror of 500 mm in diameter.