Measurement of activation cross sections of the target and the proton beam window materials at J-PARC

Matsuda, Hiroki  ; Meigo, Shinichiro   ; Iwamoto, Hiroki   

For the improvement of the accuracy of nuclear design for spallation neutron sources and transmutation systems, nuclear reaction cross sections are required. Considering decommissioning of the accelerator facilities, accurate cross sections are mandatory. The activation cross sections have been measured in several facilities. However, they have low accuracy and precision. Especially, since there is almost no data for 3 GeV protons which are used for spallation neutron source (JSNS) in J-PARC, the experimental data is required for the improvement of the target materials.For the sake of the forthcoming full-time measurement of the activation cross sections for various nuclei, we measured the ones of aluminium with 0.4, 1.3, 2.2, and 3.0 GeV protons as the test purpose. It was found that more accurate data than current ones would be measured by using precise beam controls and highly accurate beam monitoring. We compared the experimental data, the evaluated data (JENDL-HE/2007), and the calculations with several intra-nuclear cascade models by PHITS code. Although the experimental data agreed with JENDL-HE/2007, the calculations underestimated about 40%. This could come from the evaporation model (GEM) being included in PHITS code. We found that the calculations agreed with the experimental data by upgrading PHITS code.