12C(n, n+3α) and 12C(n, α0)9Be cross sections in the MeV neutron energy region

mechanism and in the applications of nuclear technology. However, large differences (approximate to 200%) exist in the C-12(n, n+3 alpha) cross section data of measurements and evaluations. Using a single crystal chemical vapor deposited (sCVD) diamond detector as an active target, cross sections of the C-12(n, n+3 alpha) and C-12(n, alpha(0))Be-9 reactions were measured simultaneously in the neutron energy region of 9.50 - 14.67 MeV. The present cross sections of the C-12(n, alpha(0))Be-9 reaction are consistent with the results of the latest measurement, which confirms the reliability of this work. The measurement results of the C-12(n, n+3 alpha) reaction with uncertainties smaller than 15% contribute to effectively clarify the discrepancies of the measurements and evaluations. To our knowledge, this is the first time to measure the C-12(n, n+3 alpha) cross sections using the diamond detector as an active target. Our method can be used in the future measurements to constrain the C-12(n, n+3 alpha) excitation function in a much wider neutron energy region. R-matrix analysis was carried out for n+C-12 system using the RAC code in the neutron energy region below 30 MeV. Systematic and reliable calculation results are obtained for various reaction channels. (C)2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).