Measurement of displacement cross-sections of copper and iron for proton with kinetic energies in the range 0.4 – 3 GeV
Hiroki Matsuda, Shin-ichiro Meigo, Yosuke Iwamoto, Makoto Yoshida, Shoichi Hasegawa, Fujio Maekawa, Hiroki Iwamoto, T. Nakamoto, Taku Ishida, Shunsuke Makimura
Abstract
To estimate the structural damages of materials in accelerator facilities, displacement per atom (dpa) is widely employed as a damage index, calculated based on the displacement cross-section obtained using a calculation model. Although dpa is applied as standard, the experimental data of the displacement cross-section for a proton in the energy region above 20 MeV are scarce. Among the calculation models, difference of about factor 8 exist, so that the experimental data of the cross-section are crucial to validate the model. To obtain the displacement cross-section, we conducted experiments at the Japan Proton Accelerator Research Complex (J-PARC). The displacement cross-section of copper and iron was successfully obtained for a proton projectile with the kinetic energies, 0.4, 0.8, 1.3, 2.2, and 3 GeV. The results were compared with those obtained using the widely utilized Norgertt–Robinson–Torrens (NRT) model and the athermal–recombination–corrected dpa (arc-dpa) model based on molecular dynamics (MD). It was found that the NRT model overestimates the present displacement cross-section by 3.5 times. The calculation results obtained using with the arc-dpa model based on the Nordlund parameter show remarkable agreement with the experimental data. It can be concluded that the arc-dpa model must be employed for the dpa calculation for the damage estimation of copper and iron.