Thermal desorption analysis of beryllium tile pieces from JET

Pieces of beryllium tile exposed to a D–D plasma in JET have been studied by thermal desorption spectroscopy. These tiles have a thick layer of redeposited Be–C–O with considerable hydrogen and deuterium present. The samples were heated at a constant rate of 2°C/min, from 100°C to 900°C. Desorption peaks occurred in the range of 140–480°C. There was no significant desorption at temperatures above 600°C. The amount of deuterium detected varied from a low of 8×1021/m2 to a high of 2.1×1023/m2. In one case, the amount of deuterium in a tile piece was seven times greater than the amount in a neighboring tile piece. Some of the tile pieces in the plasma-exposed region showed surface melting. Despite this, the deuterium yield from one of these pieces is >1023/m2.