[Table of Contents]

Plasma and Fusion Research

Volume 2, 011 (2007)

Rapid Communications

Investigation of Carbon Films on Material Probes in the Vicinity of Local Island Divertor in the Large Helical Device
Tomoaki HINO, Tomoya HIRATA, Yuji NOBUTA, Suguru MASUZAKI1), Naoko ASHIKAWA1), Akio SAGARA1), Nobuaki NODA1), Nobuyoshi OHYABU1), Akio KOMORI1), Osamu MOTOJIMA1) and LHD Experimental Group1)
Laboratory of Plasma Physics and Engineering, Hokkaido University
1)
National Institute for Fusion Science
(Received 9 March 2007 / Accepted 27 March 2007 / Published 23 April 2007)

Abstract

Two sets of material probes were installed in LHD in the vicinity of the Local Island Divertor (LID) head made of carbon fiber composite. One set of the material probes faced the LID head, while the other set was placed in a shallow line of sight to the head. Carbon films on the former and the later sets of probes are expected to be formed by the deposition of physically sputtered carbon atoms and chemically sputtered hydrocarbon, respectively, during the LID discharges. Surface morphology and thickness of the films, and the amount of retained hydrogen in the films were investigated, and hydrogen concentration in the probes was estimated. The hydrogen concentration in the carbon films on the probes placed in a shallow line of sight of the head was significantly large with the atomic ratio of H/C = 0.6-1.1.

Keywords

carbon film, hydrogen retention, Local Island Divertor, Large Helical Device, tritium concentration, carbon dust, ITER

DOI: 10.1585/pfr.2.011

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This paper may be cited as follows:

Tomoaki HINO, Tomoya HIRATA, Yuji NOBUTA, Suguru MASUZAKI, Naoko ASHIKAWA, Akio SAGARA, Nobuaki NODA, Nobuyoshi OHYABU, Akio KOMORI, Osamu MOTOJIMA and LHD Experimental Group, Plasma Fusion Res. 2, 011 (2007).