Measurement of displacement cross-sections of Nb irradiated by protons with kinetic energy range between 0.4 and 3 GeV

Abstract

In high-intensity proton accelerator facilities, it is crucial to evaluate the damage of beam-interception materials and accelerator components, such as a superconducting magnet coil and cavity. The displacement per atom (dpa) is used as a damage index derived by integrating the particle flux and the displacement cross section. 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. To obtain the data for superconducting materials for high-intensity accelerators and magnets, we measured the displacement cross section of Nb for proton irradiation with a kinetic energy range between 0.4 and 3 GeV at J-PARC. The present experimental results were compared with the calculation of PHITS code and Karlsruhe Institute of Technology (KIT) evaluation using both NorgerttRobinson-Torrens (NRT) and the athermal recombination corrected dpa (arc-dpa) models. The experiment showed that the widely utilized NRT model overestimates the cross section by 50%. It is also found that the arc-dpa model shows remarkably good agreement with the present data.