TEM and EELS characterization of carbon dust and co-deposited layers from the TEXTOR tokamak

Co-deposited layers and dust agglomerates formed at TEXTOR tokamak were collected and examined in detail by means of transmission electron microscopy and electron energy-loss spectroscopy. The analysis has shown that thick deposits and dust contain mainly carbon with an admixture of boron precipitates and small amounts of other elements. The carbon deposit was mostly amorphous, while strips were graphite crystallites embedded in dust agglomerates. In thin co-deposits on the collector probe very small graphite crystallites were piled up with a preferential orientation. The results are discussed in terms of processes decisive for the erosion of plasma facing components and for the fuel retention.