Darmstadt 2008 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 4: Magnetischer Einschluss I

P 4.2: Vortrag

Dienstag, 11. März 2008, 15:15–15:30, 2G

Compact Soft X-Ray Spectrometer for Argon Measurements at ASDEX-Upgrade — •Marco Sertoli, Rudolf Neu, Thomas Pütterich, Ralph Dux, and ASDEX Upgrade Team — Max-Plank-Institut für Plasmaphysik, Garching, Deutschland

In next step fusion plasmas, radiation cooling by seed impurities will be mandatory to keep the divertor power load below 10 MW/m². The use of medium-Z elements, such as Neon and Argon, as radiators in a full tungsten device is under investigation at ASDEX-Upgrade. To monitor these impurities, a new ITER prototype X-ray spectrometer has been installed on ASDEX-Upgrade. This diagnostic is a high-resolution compact Johann spectrometer currently optimized for Argon He-like X-ray spectra measurements. The crystal used is a high purity quartz of 35x20 mm² area, 0.2125 nm lattice spacing, 21.9 degrees asymmetrical cut, spherically bent to a curvature radius of 500 mm. Absolute intensity calibration has been achieved with a custom X-ray tube that simulates the plasma extended source, and geometric ray-tracing simulations have been carried out for correct data interpretation. The first experimental data is in good agreement with other diagnostics. Radiatively cooled scenarios are under development at ASDEX-Upgrade and the use of this diagnostic will guarantee a good time resolution (up to 4 ms) in the monitoring of Argon central particle balance and emission characteristics.