Temperature dependence of surface topography and deuterium retention in tungsten exposed to low-energy, high-flux D plasma

Surface topography and deuterium retention in tungsten have been examined after exposure to a low-energy (38 eV/D), high-flux (1022 D/m2s) deuterium plasma at ion fluences of 1026 and 1027 D/m2 and various temperatures. The methods used were scanning electron microscopy equipped with focused ion beam, thermal desorption spectroscopy, and the D(3He,p)4He nuclear reaction at 3He energies varied from 0.69 to 4.0 MeV. During exposure to the D plasma, blisters with various shapes and sizes depending on the exposure temperature are formed on the W surface. At the temperatures above 700 K no blisters appear. The deuterium retention increases with the exposure temperature, reaching its maximum value of about 1022 D/m2 at 480–530 K, and then decreases to about 1019 D/m2 at 800 K.