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

Author(s)

, Pablo Torres-Sánchez, Javier Praena, Ignacio Porras, Marta Sabaté-Gilarte, Claudia Lederer-Woods, Oliver Aberle, Victor Alcayne, Simone Amaducci, Józef Andrzejewski, Laurent Audouin, Vicente Bécares, Victor Babiano-Suarez, Michael Bacak, Massimo Barbagallo, František Bečvář, Giorgio Bellia, Eric Berthoumieux, Jon Billowes, Damir Bosnar, Adam Brown, Maurizio Busso, Manuel Caamaño, Luis Caballero, Francisco Calviño, Marco Calviani, Daniel Cano-Ott, Adria Casanovas, Francesco Cerutti, Yonghao Chen, Enrico Chiaveri, Nicola Colonna, Guillem Cortés, Miguel Cortés-Giraldo, Luigi Cosentino, Sergio Cristallo, Lucia Anna Damone, Maria Diakaki, Mirco Dietz, César Domingo-Pardo, Rugard Dressler, Emmeric Dupont, Ignacio Durán, Zinovia Eleme, Beatriz Fernández-Domínguez, Alfredo Ferrari, Francisco Javier Ferrer, Paolo Finocchiaro, Valter Furman, Andreas Pavlik, Gavin Smith

Abstract

Background: The N14(n,p)C14 reaction is of interest in neutron capture therapy, where nitrogen-related dose is the main component due to low-energy neutrons, and in astrophysics, where N14 acts as a neutron poison in the s process. Several discrepancies remain between the existing data obtained in partial energy ranges: thermal energy, keV region, and resonance region.Purpose: We aim to measure the N14(n,p)C14 cross section from thermal to the resonance region in a single measurement for the first time, including characterization of the first resonances, and provide calculations of Maxwellian averaged cross sections (MACS). Method: We apply the time-of-flight technique at Experimental Area 2 (EAR-2) of the neutron time-of-flight (n_TOF) facility at CERN. B10(n,α)Li7 and U235(n,f) reactions are used as references. Two detection systems are run simultaneously, one on beam and another off beam. Resonances are described with the R-matrix code sammy.Results: The cross section was measured from subthermal energy to 800 keV, resolving the first two resonances (at 492.7 and 644 keV). A thermal cross section was obtained (1.809±0.045 b) that is lower than the two most recent measurements by slightly more than one standard deviation, but in line with the ENDF/B-VIII.0 and JEFF-3.3 evaluations. A 1/v energy dependence of the cross section was confirmed up to tens of keV neutron energy. The low energy tail of the first resonance at 492.7 keV is lower than suggested by evaluated values, while the overall resonance strength agrees with evaluations. Conclusions: Our measurement has allowed determination of the N14(n,p) cross section over a wide energy range for the first time. We have obtained cross sections with high accuracy (2.5%) from subthermal energy to 800 keV and used these data to calculate the MACS for kT=5 to kT=100 keV.

Organisation(s)

Isotope Physics

External organisation(s)

Universidad de Granada, European Organization for Nuclear Research (CERN), Universidad de Sevilla, University of Edinburgh, Centro de Investigaciones Energeticas Medioambientales y Tecnológica, Istituto Nazionale di Fisica Nucleare (INFN), Roma, Università degli Studi di Catania, University of Lodz, IPHC, Universitat de València, Technische Universität Wien, Université Paris Saclay, Charles University Prague, University of Manchester, University of Zagreb, University of York, Università degli Studi di Perugia, Universidade de Santiago de Compostela (USC), Universitat Politècnica de Catalunya, Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, INAF-Osservatorio Astrofisico di Torino, Università degli Studi di Bari Aldo Moro, National Technical University of Athens (NTUA), Paul Scherrer Institute, University of Ioannina, Centro Nacional de Aceleradores (CNA), Dubna

Journal

Physical Review C

Volume

107

No. of pages

15

ISSN

2469-9985

DOI

https://doi.org/10.1103/PhysRevC.107.064617

Publication date

06-2023

Peer reviewed

Yes

Austrian Fields of Science 2012

103014 Nuclear physics

ASJC Scopus subject areas

Nuclear and High Energy Physics

Portal url

https://ucrisportal.univie.ac.at/en/publications/46f8f8e1-4d92-4cde-a2af-203d66ac4834