Dynamic CT system for visible light emission from tokamak plasma with charge coupled detectors

A tomographic reconstruction system with five channels for visible light emission has been developed and applied to observe the visible light emission from HYBTOK-II tokamak plasma. A compact and low cost computed tomography (CT) system with a good spatial and time resolution was established using an array of charge coupled devices. The shuttering capability of the CT system is 300μs. A rapid change of the emission profile due to the deviation from the tokamak equilibrium was successfully followed. Present CT system with five CCD cameras enables us to recognize a local increment of the visible light emission due to the plasma arcing, which is difficult to observe with the conventional three camera CT system, which is often employed for fusion plasma diagnostics. (author)