Deuterium trapping in low-Z coatings

Measurements of deuteron trapping in a series of low-Z wall coatings, proposed for use in JET, are reported. Mass spectrometry has been used to study the re-emission of incident ions of 100 eV-2 keV D2+ during bombardment at implant temperatures of between 300 K and 1100 K. Titanium carbide coatings of 20 μm thickness are found to trap large quantities of deuterium at temperatures <= 800 K. Other samples, including alumina, silicon and titanium dioxide all show a saturation behavior following ion doses >= 1018 deuterons cm-2. Under certain bombardment conditions an increase in trapping is recorded as the implant temperature is increased from 600 K to 800 K. The implications of these results for the tritium inventory when using D/T plasmas is discussed. (orig.)