Measurement of DPA cross-section of 0.4 - 3 GeV proton at J-PARC

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

For a damage evaluation of targets and beam window for a high-intensity proton accelerator facility, DPA based on a model calculation of a cross section of displacement per atom (DPA). However, the models are not sufficiently validated since there are almost no data induced by protons above 20 MeV. Thus, we measure DPA cross section for various measurement at J-PARC by using 0.4-3.0 GeV protons. DPA cross section can be obtained by dividing a resistivity increase after proton irradiation by the resistivity per Frenkel pairs. In this measurement, the sample were placed onto a front edge of a two-stage 4K GM cryocooler (Sumitomo Heavy Industries, Ltd.). In this measurement, an copper wire (diameter 0.25 mm) that was annealed by 800C was employed. The experiment is performed with low-intensity beam at 3NBT line where the proton beam is transported from 3 GeV Synchrotron (RCS) to the Material and Life science Facility (MLF). We started vacuum pumping after an installation and we confirmed that the pressure level achieved the one where the beam can be transported. The achieved temperatures were 4 K around the front edge of the cryocooler and 20 K around the sample due to radiation heat. In this talk, we report a current status of experiment and discuss an effect of a beam profile to the DPA cross section.