Deuterium release rates in a-C:D-layers during oxygen attack

A laboratory produced very homogeneous a-C:D-layer (DIARC, 3.5 mu m of thickness, D/C = 0.1) is oxidised in oxygen (0.3-20 kPa) at temperatures of 523-723 K in order to generate D-releases; the results are used in development of a cleaning procedure of fusion reactor first walls from tritium. It is found, that the temperatures necessary for a continuous release are in the case of the DIARC specimen higher by about 100 K than for TEXTOR specimen examined earlier. Within the 50 K steps used, the burst-like D-release as observed for TEXTOR specimen at lower temperatures was not found for DIARC. Raman and SIMS spectra for both kinds of specimen are reported. (C) 1999 Elsevier Science B.V. All rights reserved.