Influence of blistering on deuterium retention in tungsten irradiated by high flux deuterium 10–100 eV plasmas

The influence of blistering on deuterium retention in polycrystalline tungsten (W) has been studied at incident energies of tens of eV and a fixed incident flux of 1 × 1022 D/m2/s. The surface morphology was observed using scanning electron microscopy (SEM) and the deuterium retention in the irradiated samples measured using thermal desorption spectrometry (TDS). The results indicate that at substrate temperature around 400–500 K dense and high dome-shaped blisters appeared at the surface and the deuterium retention also reached its maxima. The blisters then became lower and sparse and finally disappeared at 900 K. Additionally, the D retention decreased to a quite low level above 700 K. Thermal desorption spectra of the deuterium in the irradiated samples showed four peak temperatures as a function of the substrate temperature during irradiation, indicating different types of trapping sites.