Deuterium retention in sintered boron carbide exposed to a deuterium plasma

Depth profiles of deuterium up to a depth of 10 mu m have been measured using the D(3 He P)4 He nuclear reaction in a resonance-like technique after exposure of sintered boron carbide, B4C, at elevated temperatures to a low energy (approximate to 200 eV/ D) and high ion flux (approximate to 10(21) m(-2) s(-1)) D plasma. The proton yield was measured as a function of incident He-3 energy and the D depth profile was obtained by deconvolution of the measured proton yields using the program SIMNRA. D atoms diffuse into the bulk at temperatures above 553 K, and accumulate up to a maximum concentration of about 0.2 at.%. At high fluences (>= 10(24) D/m(2)), the accumulation in the bulk plays a major role in the D retention. With increasing exposure temperature, the amount of D retained in B4C increases and exceeds a value of 2 x 10(21) D/m(2) at 923 K. The deuterium diffusivity in the sintered boron carbide is estimated to be D = 2.6 x 10(-6) exp{-(107 +/- 10) kJ mol(-1)/RT}m(2) s(-1). (c) 2005 Published by Elsevier B.V.