Characteristics of traps for hydrogen in helium-irradiated copper

Characteristics of traps for hydrogen in helium-irradiated copper were experimentally studied by use of nuclear reaction analysis (NRA). Samples were continuously charged with deuterium from RF plasma during the experiment. The results showed that two types of traps associated with radiation damage were produced, called traps 1 and 2 here. From the temperature dependence of the deuterium concentration observed by NRA and the deuterium permeation flux, the trapping energies were estimated to be 0.65 eV for trap 1 and 0.57 eV for trap 2. The production ratio of trap 1 per atomic displacement was 0.0021. The density of trap 2 reached a constant value of 6 × 1025 m−3 at high irradiation doses. Traps 1 and 2 are assumed to be vacancy clusters and interstitial loops, respectively.