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  • A new sniffer probe for the determination of hydrogen isotope ratios in the W7-AS stellerator A new sniffer probe for the determination of hydrogen isotope ratios in the W7-AS stellerator A new sniffer probe for the determination of hydroge

Abstract

An improved sniffer probe was constructed for measurements of the hydrogen isotope ratio and impurities in the plasma edge of the W7-AS stellerator. Details of the new design and the probe performance are presented. The new design allows changing the head without breaking the vacuum in the torus. It has a high mechanical stability, effective screening of the magnetic field and high sensitivity. The gas dynamic properties of the probe are analyzed using transmission line calculus, resulting in a rise time of 114ms for hydrogen. During the 1997 spring measurement campaign, H/D isotope ratio measurements were carried through showing considerable outgassing of the walls during and after discharge. He glow discharges reduce the isotope ratio drastically. Results from a typical experiment day are presented together the analytic procedure for determining the isotope ratio in both the plasma edge and in the neutral gas region between the plasma and the vessel walls.

Additional information

Authors: MAX-PLANCK-INSTITUT FUR PLASMAPHYSIK, ;GARCHING (DE),
Bibliographic Reference: Article: Review of Scientific Instruments, 70 (1999) 7, 3007-3014
Record Number: 199911419 / Last updated on: 1999-10-01
Category: PUBLICATION
Original language: en
Available languages: en
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