Erosion and deuterium retention behavior of tungsten exposed to impurity-seeded deuterium plasma

Abstract

The effect of plasma impurity seeding on erosion and deuterium (D) retention behavior of tungsten (W) is investigated on linear experimental plasma system (LEPS). The incident D energy is 38 and 71 eV per D, and the D fluence varies from 3 × 10 23 to 1 × 10 26 D•m -2 . The results of erosion reveal that argon (Ar) seeding strongly enhances erosion, helium (He) seeding slightly increases sputtering yield depending on the ratio of He in plasma, while nitrogen (N) seeding inhibits erosion and reduces the sputtering yield. Furthermore, O impurity dominates the erosion behavior during pure D plasma exposure when the D incident energy is lower than the sputtering threshold of W by D. For blistering and D retention behavior, compared with pure D exposure, Ar seeding reduces the amount and increases the size of blister, and leads to the increase of D inventory. He seeding has the opposite result, showing almost no blisters at sample surface and a dramatic drop in D retention. D retention decreases with increasing N content, and ruptured blisters are observed at a high D fluence of 1 × 10 26 D•m -2 .

Deuterium retention in heavy-ion and helium-ion sequentially irradiated tungsten

“…All samples were exposed for 2.8 h corresponding to a total D fluence of 1.0 × 10 25 D m −2 . The incident ion energy was selected to be 38 eV D −1 , determined by the −100 V bias voltage applied to the sample holder and the 15 V plasma floating potential, as described in [26]. During D plasma exposure, a sample temperature of 450 K was chosen to ensure that a sufficient amount of D could diffuse into the damaged region, as well as to avoid defect annealing such as vacancy migration [27].…”