Abstract
Tungsten (W) targets have been exposed to high density (ne ≤ 4 × 1019 m-3), low temperature (Te ≤ 3 eV) CH4-seeded deuterium (D) plasma in Pilot-PSI. The surface temperature of the target was ∼1220 K at the center and decreased radially to ∼650 K at the edges. Carbon film growth was found to only occur in regions where there was a clear CII emission line, corresponding to regions in the plasma with Te ≥ 2 eV. The maximum film thickness was ∼2.1 μm after a plasma exposure time of 120 s. 3He nuclear reaction (NRA) analysis and thermal desorption spectroscopy (TDS) determine that the presence of a thin carbon film dominates the hydrogenic retention properties of the W substrate. Thermal desorption spectroscopy analysis shows retention increasing roughly linearly with incident plasma fluence. NRA measures a C/D ratio of ∼0.002 in these films deposited at high surface temperatures.
Original language | English |
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Pages (from-to) | 176-180 |
Number of pages | 5 |
Journal | Journal of Nuclear Materials |
Volume | 396 |
Issue number | 2-3 |
DOIs | |
State | Published - Jan 31 2010 |
Externally published | Yes |
Funding
This work, supported by the European Communities under the contract of the Association EURATOM/FOM, was carried out within the framework of the European Fusion Programme with financial support from NWO. The views and opinions expressed herein do not necessarily reflect those of the European Commission.