Deuterium trapping near vanadium surface bombarded with hydrogen ions

Depth profiles of deuterium near surface of a vanadium sample were observed by nuclear reaction analysis. Irradiation defects were introduced in the sample by bombardment of 0.3-MeV H ions with a dose of 3.9 × 1021 m−2. During the experiment, the sample was continuously exposed to a rf plasma to be charged with deuterium atoms. The result showed that deuterium trapping sites (traps) were produced by the bombardment and the deuterium concentration increased by several times. The depth profile of trapped deuterium was similar to the distribution of atomic displacement. The traps began to decrease at 470 K, which agreed with the recovery temperature for point defects. From these results, the traps were considered to be vacancies, probably stabilized by impurity atoms or the irradiation defects. The ratio of the number of the traps to the displaced host atoms was estimated to be 0.026 at lower bombarding doses, which became lower at higher doses.