Reduction of radiation-enhanced sublimation of graphite under high flux beam irradiation

• Published in: Journal of nuclear materials Vol. 227; no. 3; pp. 251 - 258
• Main Authors: Ueda, Yoshio, Nakano, Kaori, Ohtsuka, Yusuke, Isobe, Michiro, Goto, Seiichi, Nishikawa, Masahiro
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1996
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/0022-3115(95)00158-1

Radiation-enhanced sublimation (RES) of isotropic graphite was studied under high flux beam irradiation. Irradiation was performed with a 5 keV Ar beam with a maximum flux of 1.5 × 10
21 m
−2 s
−1, about two orders of magnitude higher than that of previous beam experiments. It is found that the total erosion yield of isotropic graphite at 1980 K under high flux conditions of 1 × 10
21 m
−2 s
−1 is reduced to a value of about 3 in comparison with a yield of 5.9 under low flux conditions of 3.5 × 10
19 m
−2 s
−1. The dependence of the RES yield (total yield subtracted by physical sputtering yield) on the flux
φ (
φ > 1 × 10
20 m
−2 s
−1) is as
φ
−0.26, which is much stronger than that obtained in the low flux region (
φ
−0.07,
φ < 1 × 10
19 m
−2 s
−1). The RES model based on diffusion and annihilation of C self-interstitials including stable defects for the sinks of interstitials is discussed in terms of the flux dependence of RES yield.