C12(p, n)N12reaction at 99 MeV

Cross sections were measured for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(p, n){}_{}{}^{12}{}_{}{}^{}\mathrm{N}$ reaction at 99.1 MeV for nine laboratory angles between 0° and 48.5°. Two detector stations were used: one at 68.0 m was for angles between 0° and 24.5°, the other at 76.3 m for angles between 24° and 48.5°. Overall energy resolutions of 260 and 230 keV for neutrons of about 80 MeV were achieved at the first and second detector stations, respectively, with large-volume mean-timed counter assemblies. Cross sections for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{N}$ ground state ($1^{+}$) and 0.96 MeV state ($2^{+}$) are compared with a distorted-wave impulse approximation calculation using an effective nucleon-nucleon interaction derived from nucleon-nucleon scattering data. For the ground state, the magnitudes of the calculated cross sections agree with the measured cross sections at forward angles but significantly underestimate the measured values beyond about 30°; for the 0.96 MeV state, the calculated cross sections must be reduced by 30% to obtain agreement with the cross sections measured at forward angles.