Surface modifications and deuterium retention in polycrystalline and single crystal tungsten as a function of particle flux and temperature

The effects of particle flux and exposure temperature on surface modifications and deuterium (D) retention were systematically investigated on four different tungsten (W) microstructures. As-received, recrystallized, and single crystal W samples were exposed to D plasmas at surface temperatures of 530-1170 K. Two different ranges of D ion fluxes (1022 and 1024 D+m−2s−1) were used with the ion energy of 40 eV and particle fluence of 1026 D+m−2. Increasing the particle flux by two orders of magnitude caused blister formation and D retention even at temperatures above 700 K. The main effect of increasing the particle flux on total D retention was the shifting of temperature at which the retention was maximal towards higher temperatures. Diffusion-trapping simulations were used to fit the thermal desorption spectroscopy (TDS) release peaks of D, yielding one or two types of trapping sites with de-trapping energies around 2 eV.