Fusion reactions break down gaseous hydrogen electrically, forming a plasma. Plasma particles heat up to fusion temperatures and create fusion reactions, releasing huge amounts of energy. Fusion reactors such as tokamaks use tiles made of Tungsten for the interior section exposed to the highest heat and particle fluxes. A major goal of research into fusion materials testing involves exploring material performance in deuterium, helium, or mixed plasmas. The ability to effectively measure helium and deuterium in plasmas simulating fusion plasmas or the effect on plasma facing materials after exposure to such plasmas through techniques such as TDS and TPD is critical to developing our understanding proposed materials’ suitability for long-term use in fusion and other plasma facing applications. An Extrel VeraSpec HRQ (High Resolution Quadrupole) Mass Spectrometer was used for the analysis of gas phase components expected in fusion reactions. A certified cylinder containing helium and deuterium was leaked into the vacuum chamber to characterize the long term mass stability of the system under high resolution conditions. This gas was then diluted to determine the low detection limits of these species under the same conditions. A certified cylinder containing carbon monoxide and nitrogen was also leaked into the vacuum chamber to assess the system’s ability to resolve the spectrum of this mixture. Spectra at six hour time intervals were taken of the helium and deuterium mixture over 24 hours. The experiment demonstrated that, under high resolution conditions, no detectable mass spectral changes were observed. Diluting the mixture, detection limits of approximately 10ppm (parts per million) were calculated for helium and deuterium. Quadrupole mass spectrometry provides a low cost, simple experimental setup to monitor the effects of fusion reactions on reactor materials.

High-resolution quadrupole mass spectrometry analysis for fusion reactor and plasma facing materials

2019 Fall National Meeting

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