SMuK 2021 – scientific programme
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P: Fachverband Plasmaphysik
P 17: Poster II
P 17.13: Poster
Friday, September 3, 2021, 14:00–16:00, P
Towards the operation of a high-resolution mass spectrometer for exhaust gas analysis at ASDEX Upgrade — •Antonello Zito1,2, Thomas Schwarz-Selinger1, Volker Rohde1, Athina Kappatou1, and Marco Wischmeier1 — 1Max-Planck-Institut für Plasmaphysik, Garching, Germany — 2Physik-Department E28, Technische Universität München, Garching, Germany
The removal of helium, which is the product of the D-T reaction, in magnetic fusion devices must be as efficient as possible in order to avoid fuel dilution and not degrade the confinement properties. Optimizing the strategies for a good helium pumping is possible by monitoring the behavior of the exhaust gas in helium-seeded plasma discharges in currently operating devices. In the framework of helium exhaust studies, a high-resolution quadrupole mass spectrometer has been recently installed at the pumping ducts of the ASDEX Upgrade tokamak. This diagnostic has been proven successful in discriminating molecules of deuterium and atoms of helium, which have a tiny mass difference of only 0,025 AMU, with elevated accuracy. The capability of detecting even trace levels of helium (< 5%) in a deuterium gas has been confirmed. However, the harsh environment involving the presence of radiations and intense currents in proximity of the instrument is seen to strongly affect the reliability of the measurements during plasma operations. In this work we will present some of the challenges which were faced during the efforts towards the detection of helium in the exhaust gas of ASDEX Upgrade using this technique.