Speaker
Gennady Sergienko
(Forschungszentrum Jülich GmbH)
Description
Deuterium-tritium gas mixture will be used as fuel in future fusion devises like ITER. Thus it is important to monitor hydrogen isotope ratios not only in fusion plasma and in the subdivertor/exhaust gases but also retained in the plasma facing components (PFC). Residual gas analysis is traditionally used to quantify the isotope species of the PFCs in the laboratory by means of thermal desorption spectroscopy (TDS). The drawback of this method is that the mass peaks of the isotopes cracking patterns and helium superimpose and complicate data analyses as well as accurate quantification.
Atomic spectral lines emitted from a Penning discharge are used to quantify partial pressures and isotopes ratios in gases. To identify the potential of this method for TDS studies, the hydrogen emission spectrum lines (Hα and Dα) were examined by Alcatel type Penning gauge. The hydrogen/deuterium pressures were measured by both a membrane vacuum gauge and the Penning gauge. Different gas mixtures were produced by varying of hydrogen/deuterium flows. The Hα and Dα Balmer series lines intensities were recorded with help of a high etendue spectrometer coupled to the Penning gauge using relay optics together with fiber bundle and equipped with Peltier cooled CCD camera. Subsequent measurements using hydrogen and deuterium gases revealed for identical pressures in the range of 10-7-7-10-3-3 mbar that the Hα line intensities are systematically higher by a factor of 1.25 with respect to the Dα line intensities. This observation can be explained by the dissociative excitation of the hydrogen molecules which has been found previously in electron beam excitation experiments [1]. Results of Hα/Dα line intensity measurements for different gas mixtures and pressures will be presented and a more accurate approach of isotope ratios determination will be discussed.
[1] C. Karolis, E. Harting, J. Phys. B: Atom. Molec. Phys. 11 (2) (1978) 357
Co-authors
Alexander Huber
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), Jülich, Germany)
Christian Linsmeier
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), Jülich, Germany)
Gennady Sergienko
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), Jülich, Germany)
Hans Gunter Esser
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), Jülich, Germany)
Marko Nonhoff
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), Jülich, Germany)
Michaele Freisinger
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), Jülich, Germany)
