Displacement cross-section of aluminum induced by neutrons and protons

Meigo, Shinichiro   ; Matsuda, Hiroki  ; Iwamoto, Yosuke   ; Nakano, Keita   

In high-intensity proton accelerator facilities such as ADS, damage estimation of materials is important. Displacement induced by radiation is estimated by the number of displacements per atom (dpa), which is given by the displacement cross-section and the particle flux. Although experimental data are required to validate the calculation model for the displacement cross-section, the experimental data is scarce in the energy region higher than 20 MeV. We carried out the experiment for proton incident at the J-PARC 3GeV synchrotron and MR accelerator facilities. Aluminum alloy has been utilized as the proton beam window for the spallation neutron source at J-PARC. In the future planned facilities at J-PARC, the proton beam window will receive a beam with a higher current density than MLF. It is important to compare the cross-section of neutrons incident to evaluate the displacement of beam windows by neutrons. From the past experimental data irradiated with the 14 MeV neutrons on an aluminum sample cooled to cryotemperature.