REEMISSION OF DEUTERIUM FROM PURE AND BORONIZED GRAPHITE

Measurements of the re-emitted flux of deuterium implanted into pure and boronized graphite at temperatures between 300 K and 1500 K have been performed. The flux of deuterium, re-emitted after reaching saturation, decreases with increasing temperatures above 800-1000 K. At 1400 K, the re-emission coefficient amounts to about 60% in USB15 boronized graphite compared to about 35% in EK98 graphite. Diffusion of deuterium into deep regions of the target with different diffusion constants of the different target materials is one possible explanation of this behaviour. The CD4 production is similar in both cases; at 800 K, 20-25% of the deuterium is re-emitted as methane.