Cross section measurement for the 16O(n, α0)13C reaction in 6.8-11.7 MeV neutron energy region

AbstraktAbstract

Cross sections of the 16O(n, alpha 0)13C reaction were measured in the 6.8-11.7 MeV neutron energy region based on the HI-13 tandem accelerator of China Institute of Atomic Energy (CIAE). Two experiments were performed in 2022 and 2023 at total 21 neutron energy points. A gridded ionization chamber (GIC) was used as the charged particle detector, with working gas of 3.0 atm Kr+4.0%CO2 in 2022 and 4.0 atm Kr+3.0%CO2 in 2023. The oxygen atoms in the CO2 were used as the gas sample. A 238U3O8 sample inside the GIC was used to determine the neutron fluences and an EJ-309 scintillation detector was placed on the beam line to measure the neutron energy spectra to correct the events induced by the low-energy neutrons. Based on the present measurement cross sections and existing measurement data from the EXFOR library, R-matrix analysis was carried out for the n+16O system using the RAC code. Present cross sections are compared with existing measurement data and evaluation data. In the 6.8-9.5 MeV neutron energy region our measurement results are consistent with the evaluation data in the ENDF/B-VIII.1 library. In the 9.5-11.7 MeV neutron energy region, A peak near 10.5 MeV in the excitation function in our measurement and R-matrix calculation results was obtained while the excitation functions given by the evaluations and existing measurements have a valley structure.

Cross sections of the 16O(n, alpha 0)13C reaction were measured in the 6.8-11.7 MeV neutron energy region based on the HI-13 tandem accelerator of China Institute of Atomic Energy (CIAE). Two experiments were performed in 2022 and 2023 at total 21 neutron energy points. A gridded ionization chamber (GIC) was used as the charged particle detector, with working gas of 3.0 atm Kr+4.0%CO2 in 2022 and 4.0 atm Kr+3.0%CO2 in 2023. The oxygen atoms in the CO2 were used as the gas sample. A 238U3O8 sample inside the GIC was used to determine the neutron fluences and an EJ-309 scintillation detector was placed on the beam line to measure the neutron energy spectra to correct the events induced by the low-energy neutrons. Based on the present measurement cross sections and existing measurement data from the EXFOR library, R-matrix analysis was carried out for the n+16O system using the RAC code. Present cross sections are compared with existing measurement data and evaluation data. In the 6.8-9.5 MeV neutron energy region our measurement results are consistent with the evaluation data in the ENDF/B-VIII.1 library. In the 9.5-11.7 MeV neutron energy region, A peak near 10.5 MeV in the excitation function in our measurement and R-matrix calculation results was obtained while the excitation functions given by the evaluations and existing measurements have a valley structure.