Copper alloys selected for ITER investigated by positron annihilation spectroscopy

The work is oriented towards the study of the high-energy neutron (proton) flux induced disorder in ITER selected Cu-alloys by positron annihilation spectroscopy (PAS). Defects in the form of vacancies (loops, voids, etc.) in Cu-alloys were studied using pulsed low energy system (PLEPS). The selected specimens were implanted in Ion beam laboratory of FEI STU Bratislava. The energy of implantation was EH=2x95 keV for the molecular H2+ ion beam. Two implantation doses were chosen for both of the alloys: 1.3x1019 ions/cm2 (1.1 C/cm2) and 5x1018 ions/cm2 (0.4 C/cm2). Using PLEPS a depth profiling and a void creation (probably filled with H2) in the area from 50-480 nm was observed. The experimental simulation (for the range where protons and neutron are not thermalised) of radiation damage of ITER construction materials was successfully performed. After isochronal annealing of both materials in vacuum in range 100-600 deg. C, the recovering of defects in CuCrZr was much more effective than in CuAl25. (author)