Divertor Impurity Monitor for ITER

The design of the divertor impurity monitoring system for ITER is now well advanced. The main functions of this system are to identify impurity species and to measure the two-dimensional distributions of the particle influxes in the divertor plasmas. The expected impurities are carbon, tungsten, beryllium and copper originating from the divertor target plate and from the surface of the first wall in the main chamber. Neon and other impurity gases injected into the plasma for radiation cooling in the divertor will also be observed. The wavelength range is 200 nm to 1000 nm. This system, which is one of the most important diagnostic systems for plasma control, is included in the start-up set of ITER diagnostics1.