Charged particle pulse irradiation and damage evolution in metals

Abstract To develop nuclear materials, irradiation experiments are often performed using a pulse mode of charged particles, even though the materials are used under continuous beam conditions, such as in nuclear reactors. However, it is not clear whether the defect structure evolution is the same between the two irradiation modes. The effect of pulse irradiation on defect structure evolution was studied using 8 MeV electron irradiations for Ni, 2MeV self-ion irradiations for Fe, and reaction kinetics analysis using rate equations. The damage structures were detected using positron annihilation lifetime spectroscopy. The experiments and simulations showed the differences in the accumulation of point defects in clusters at 573 K by irradiation modes. In the electron-irradiated Ni, the accumulation of interstitials under pulse beams is higher than under continuous beams. In self-ion irradiated Fe, the effects of pulse frequencies were detected.