The effect of pre-damage distribution on deuterium-induced blistering and retention in Tungsten

Heavy ions have been widely used to simulate the effect of neutron irradiation-induced crystal defects on the plasma-wall interaction in the future fusion device. In this work, energetic argon ions were utilized to damage tungsten with the different pre-damage distributions. The pre-damage distribution is controlled by tuning ion energy and fluence. After exposure to deuterium plasma, the pre-damaged tungsten targets were analyzed to explore the impact of pre-damage distribution on deuterium-induced surface blistering and retention. Surface observation results reveal that increasing pre-damage depth and peak dpa significantly reduce the surface blister's area density, especially in diameters below ten micrometers. Meanwhile, thermal desorption spectra indicate that the given change in the pre-damage distribution barely change the type of irradiation-induced defects. The role of pre-damage increases in deuterium trapping and aggregation is discussed based on the experimental results.