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Preparation, analysis, and application of coated glass targets for the Wendelstein 7-X laser blow-off system

W7-X Team; Wegner, Th.; Geiger, B.; Foest, R.; Jansen van Vuuren, A.; Winters, V. R.; Biedermann, C.; Burhenn, R.; Buttenschön, B.; Cseh, G.; Joda, I.; Kocsis, G.; Kunkel, F.; Quade, A.; Schäfer, J.; Schmitz, O.; Szepesi, T.; Gantenbein, Gerd; Huber, Martina; Illy, Stefan; Jelonnek, John; ... mehr

Abstract (englisch):
Coated glass targets are a key component of the Wendelstein 7-X laser blow-off system that is used for impurity transport studies. The preparation and analysis of these glass targets as well as their performance is examined in this paper. The glass targets have a high laser damage threshold and are coated via physical vapor deposition with μm thick films. In addition, nm-thin layers of Ti are used as an interface layer for improved ablation efficiency and reduced coating stress. Hence, the metallic or ceramic coating has a lateral homogeneity within 2% and contaminants less than 5%, being optimal for laser ablation processing. With this method, a short (few ms) and well defined pulse of impurities with about 1017 particles can be injected close to the last closed flux surface of Wendelstein 7-X. In particular, a significant amount of atoms with a velocity of about 1 km/s enters the plasma within 1 ms. The atoms are followed by a negligible concentration of slower clusters and macro-particles. This qualifies the use of the targets and applied laser settings for impurity transport studies with the laser blow-off system in Wendelstein 7-X.

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Zugehörige Institution(en) am KIT Institut für Angewandte Materialien - Angewandte Werkstoffphysik (IAM-AWP)
Institut für Hochleistungsimpuls- und Mikrowellentechnik (IHM)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 08.2020
Sprache Englisch
Identifikator ISSN: 0034-6748, 1089-7623
KITopen-ID: 1000123337
HGF-Programm 31.03.02 (POF III, LK 01) Plasma Heizsysteme
Erschienen in Review of scientific instruments
Verlag American Institute of Physics (AIP)
Band 91
Heft 8
Seiten 083503
Projektinformation EUROfusion (EU, H2020, 633053)
Nachgewiesen in Web of Science
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