Nitrogen-assisted removal of deuterated carbon layers

• Deuterated carbon films prepared in laboratory and boronised films prepared in the TEXTOR tokamak were exposed to hydrogen-nitrogen plasmas in order to determine erosion characteristics and fuel removal efficiency. Exposures were performed in: (i) TEXTOR tokamak during ion cyclotron heated wall conditioning discharges (ICWC) and (ii) TOMAS magnetic plasma facility in radio frequency-assisted glow discharges. The essential results are: (i) films exposed in TEXTOR are not affected: deuterium and carbon content does not decrease and the morphology is unchanged, and (ii) deuterium and carbon contents in films exposed in TOMAS is reduced by 30-60% after 2 h of cleaning and topographical changes are noted. The study shows that while exposure to H-2-N-2 laboratory plasma removes a-C:D films, no effect is seen at the position of the sample exposure during tokamak ICWC plasmas. It also indicates that the removal efficiency is only weakly related to nitrogen, since the highest removal efficiency is seen with pure hydrogen plasma. A comparison to oxygen-assisted fuel removal is given.

Ämnesord

NATURVETENSKAP  -- Fysik -- Fusion, plasma och rymdfysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Fusion, Plasma and Space Physics (hsv//eng)

Nyckelord

PLASMA-FACING COMPONENTS

LABORATORY PLASMAS

TRITIUM RETENTION

ENERGY-DEPENDENCE

Plasma physics

Plasmafysik

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