Measurement of neutron-induced fission cross sections of ²³⁵U and ²³⁸U relative to n-p scattering at CSNS Back-n facility

¹ Institute of High Energy Physics, Chinese Academy of Sciences (CAS), 100049 Beijing, China
² Spallation Neutron Source Science Center, 523803 Dongguan, China
³ Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, 621900 Mianyang, China
⁴ Department of Modern Physics, University of Science and Technology of China, 230026 Hefei, China

^* Corresponding author: chenyonghao@ihep.ac.cn

Published online: 26 May 2023

Abstract

²³⁵U and ²³⁸U are very important isotopes in the nuclear energy system. Their neutron-induced fission cross sections have been measured intensively and evaluated as standard up to 200 MeV. However, as a matter of fact, the experimental data in the high-energy region are scarce. This work reports the measurement of ²³⁵, ²³⁸U(n, f) cross sections relative to n-p scattering performed at the China Spallation Neutron Source (CSNS) back-streaming neutron facility (Back-n). Preliminary results of ²³⁵, ²³⁸U(n, f) cross sections from 10 to 66 MeV are obtained, which are generally following the shape of the IAEA standard. However, significant discrepancies are observed at some given energies, which will be further studied.