Injection of nitrogen-15 tracer into ASDEX-Upgrade : New technique in material migration studies

• For the first time nitrogen-15 gas was used as a tracer for determining of global nitrogen retention in ASDEX-Upgrade. The injection done from the midplane gas inlet on the last day of the experimental campaign was followed by retrieval and ex situ analyses of many limiter and divertor tiles. The study was done by nuclear reaction analysis using the N-15(H-1,gamma He-4)C-12 process and detecting both gamma radiation and He-4. The highest and peaked concentrations of N-15, 8 x 10(16) cm(2), were found on limiters close to the injection point, while fairly homogeneous flat profiles were measured on most of the divertor plates. The measured concentrations are compared to an ASCOT simulation of the injection.

Ämnesord

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

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

Nyckelord

ASDEX-upgrade

Divertor plate

Divertor tiles

Ex situ analysis

Experimental campaign

Material migration

Nitrogen retention

Nuclear reaction analysis

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