RADIATION ENHANCED SUBLIMATION OF GRAPHITE BOMBARDED BY LOW ENERGY H(+), D(+) AND HE(+) IONS IN THE RANGE OF 50 EV TO 6 KEV
Graphite as a first wall material will be used at temperatures well above 1000 C in future fusion devices such as CIT, ITER or NET. At these temperatures the erosion under ion bombardment is drastically increased by the radiation-enhanced sublimation, at least for energies above 500 eV. For lower energies only an insufficient data base exists, although this energy regime is of special interest for fusion, and threshold effects are expected. In this paper measured yield data are reported for H(+), D(+) and He(+) ions in the energy range between 50 eV and 6 keV. The graphite temperature was sampled between 900 C and 1700 C. All data are gained at normal ion incidence. The measured yield data show a similar energy dependence as found for physical sputtering. This holds also for the threshold regime which was clearly identified. The enhancement of the erosion yield at elevated temperature can be described by an effective activation energy of 0.78 eV. The measured data are described by an analytic expression which can also be used for an estimation of the yield data for tritium.
Bibliographic Reference: EXTRACT: THE PROCEEDINGS OF THE 15TH SYMPOSIUM ON FUSION TECHNOLOGY (1988) PP. 889-893, ELSEVIER SCIENCE PUBLISHERS B.V.
Record Number: 1989128057300 / Last updated on: 1990-11-09
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