Measurement of Displacement Cross Section of Structural Materials Utilized in the Proton Accelerator Facilities with the Kinematic Energy above 400 MeV

For damage estimation of structural material in the accelerator facility, displacement per atom (DPA) is widely employed as an index of the damage calculated based on the displacement cross section obtained with the calculation model. Although the DPA is employed as the standard, the experimental data of displacement cross section are scarce for a proton in the energy region above 20 MeV. Among the calculation models, the difference exists about 8 times so that experimental data of the displacement cross section is crucial to validate the model. To obtain the displacement cross section, we conducted the experiment in J-PARC. As a preliminary result, the displacement cross section of copper was successfully obtained for 3-GeV proton. The present results showed that the widely utilized the Norgertt-Robinson-Torrens (NRT) model overestimates the cross section as suggested by the previous experiment for protons with lower energy.