Measurement of the 14N(n, p) 14C cross section at the CERN n\_TOF facility from subthermal energy to 800 keV

Background: The 14N(n, p) 14C reaction is of interest in neutron capturetherapy, where nitrogen-related dose is the main component due tolow-energy neutrons, and in astrophysics, where 14N acts as a neutronpoison in the s process. Several discrepancies remain between theexisting data obtained in partial energy ranges: thermal energy, keVregion, and resonance region. Purpose: We aim to measure the 14N(n, p)14C cross section from thermal to the resonance region in a singlemeasurement for the first time, including characterization of the firstresonances, and provide calculations of Maxwellian averaged crosssections (MACS). Method: We apply the time-of-flight technique atExperimental Area 2 (EAR-2) of the neutron time-of-flight (n\_TOF)facility at CERN. 10B(n, \& alpha;) 7Li and 235U(n, f ) reactions areused as references. Two detection systems are run simultaneously, one onbeam and another off beam. Resonances are described with the R-matrixcode SAMMY. Results: The cross section was measured from subthermalenergy to 800 keV, resolving the first two resonances (at 492.7 and 644keV). A thermal cross section was obtained (1.809 \& PLUSMN; 0.045 b)that is lower than the two most recent measurements by slightly morethan one standard deviation, but in line with the ENDF/B-VIII.0 andJEFF-3.3 evaluations. A 1/v energy dependence of the cross section wasconfirmed up to tens of keV neutron energy. The low energy tail of thefirst resonance at 492.7 keV is lower than suggested by evaluatedvalues, while the overall resonance strength agrees with evaluations.Conclusions: Our measurement has allowed determination of the 14N(n, p)cross section over a wide energy range for the first time. We haveobtained cross sections with high accuracy (2.5\%) from subthermalenergy to 800 keV and used these data to calculate the MACS for kT = 5to kT = 100 keV.