Proceedings of ITC/ISHW2007 Use of a High Resolution Overview Spectrometer for the Visible Range in the TEXTOR Boundary Plasma

Passive spectroscopy is a standard diagnostic to observe the boundary layer of fusion plasmas. This visible spectroscopy is focused on the measurement of the deuterium recycling flux as well as on the monitoring of impurity fluxes like e.g. O,He... or W,C...which result from erosion of plasma-facing components. Moreover, the ro-vibrational analysis of molecular transitions provide information about the molecular break-up in the plasma. Spectrometer for the plasma boundary have to fulfil high demands with respect to the spectral, spatial and time resolution, to the observable wavelength range, to the sensitivity and dynamic range of the detector to observe and analyse simultaneously the emission of atomic and molecular species present in the observed region. We present an overview spectrometer system which is able a) to measure at once strong atomic lines (e.g. Dα) and weak molecular bands (e.g. C2 Swan-band), b) to resolve narrow molecular lines (e.g. D2 Fulcher-α band) and allow their ro-vibrational analysis, and c) to provide information about the spatial distribution in the plasma boundary. A full characterisation of the custom-made system in cross-dispersion arrangement with respect to resolving power, simultaneous wavelength coverage, sensitivity etc. is done. Spectra examples (”footprints”) taken from an injection of C3H4 into TEXTOR are presented