Deuterium accumulation in carbon materials at high fluence

Abstract D retention in fine grain graphite MPG-8 and carbon fiber composite NB31 after exposure to plasma was investigated by means of thermal desorption spectroscopy. It was observed, that deuterium accumulation in the two materials was similar in the region of the fluence of 10 22 –4 × 10 24 D + /m 2 , though NB31 retains about twice as much. The retention in MPG-8 reveals no saturation at high fluences and no flux dependence in the range of (0.5–3.5) × 10 20 D + /m 2 s. The difference between polished and unpolished samples, as well as between samples kept in air for various times after irradiation was within the experimental uncertainty.