Release of H and He from tic, stainless steel, and graphite by pulsed electron and furnace heating

Abstract Substantial release of implanted D and 3 He from TiC coatings and SS 304, and of D from graphite, by 50ns pulsed electron beam (e-beam) heating has been observed and is compared to release by isochronal furnace heating. A substantial enhancement in the fractional D release was found for D saturated TiC (0.25 D to host atom ratio) compared with low fluence implants for both e-beam and furnace heating. This enhancement was not observed for graphite and SS 304. E-beam release of 3 He from TiC was observed to be unaffected by the presence of saturation concentrations of D. Comparison to the calculated time evolution of the temperature profiles suggests a simple model for the D release based on diffusion-limited release in the case of pulsed e-beam treatments and trap-limited release in the case of furnace bulk heating. These processes are closely related to hydrogen recycle in tokamaks and have implications for T inventory control and He ash removal.