Aachen PK 2003 – scientific programme
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P: Plasmaphysik
P 17: Poster III
P 17.30: Poster
Thursday, March 20, 2003, 17:30–19:15, Foyer
Design of Optimised VUV/XUV Spectrometers for Impurity Studies on W7-X — •Wolfgang Biel1 and Rainer Burhenn2 — 1Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster, D-52425 Jülich, Germany — 2Max-Planck-Institut für Plasmaphysik, EURATOM Ass., D-17491 Greifswald, Germany
A set of new VUV/XUV spectrometers is developed for impurity monitoring and impurity transport studies at the stellarator W7-X. The four new systems cover the entire wavelength range from 2.5 nm to 160 nm, divided into four subsections with some overlapping, thus achieving a complete coverage of prominent spectral lines from the relevant impurity elements (Z = 2 ... 30). Numerically optimised toroidal holographic diffraction gratings are designed and the spectrometer geometries and detector properties are chosen to obtain a high efficiency at a good wavelength resolution. The performance of the spectrometers is tested and optimised by means of ray tracing calculations. The intensity of spectral lines is simulated using the impurity transport code STRAHL and the achievable accuracy of the measured line intensities is discussed for typical concentrations of intrinsic plasma impurities as well as for the case of impurity injection experiments.