Measurement of displacement cross section for 8-GeV and 30-GeV protons

Meigo, Shinichiro   ; Matsuda, Hiroki  ; Iwamoto, Yosuke   ; Iwamoto, Hiroki   ; Hasegawa, Shoichi   ; Maekawa, Fujio  ; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*

In high-intensity proton accelerator facilities, the evaluation of the damage of the materials used for the beam window is essential. The damage is widely estimated by the dpa given by the displacement cross-section. Since the experimental data of the cross-section were scarce, we have started the experiment in the energy region less than 3 GeV. In order to confirm the applicability of the calculation model in the higher energy region, the cross-sections for 8 GeV and 30 GeV protons were measured at the J-PARC MR. The calculation by the NRT model showed overestimation about 2 to 4 times, as shown in the energy range below 3 GeV. It was found that the calculation with the athermal recombination correction model showed remarkably good agreement with the experiment in the energy range up to 30 GeV. It was also shown that the cross-section in the energy region above 3 GeV is proportional to the 1.2th power of the mass number of the target element.