Eur. Phys. J. A (2026) 62: 5
https://doi.org/10.1140/epja/s10050-025-01767-3

Regular Article - Experimental Physics

New measurement of $_{}^{50}$Cr and $_{}^{53}$Cr (n,$\gamma$) cross sections at n_TOF: a call for chromium nuclear data revision

¹ Universidad de Sevilla, Seville, Spain
² Centro Nacional de Aceleradores (CNA), Seville, Spain
³ Universitat Politècnica de Catalunya, Barcelona, Spain
⁴ Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
⁵ Instituto de Física Corpuscular, CSIC-Universidad de Valencia, Paterna, Spain
⁶ NAPC-Nuclear Data Section, International Atomic Energy Agency, Vienna, Austria
⁷ European Organization for Nuclear Research (CERN), Geneva, Switzerland
⁸ Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy
⁹ Department of Physics, University of Pavia, Pavia, Italy
¹⁰ INFN Laboratori Nazionali del Sud, Catania, Italy
¹¹ University of Lodz, Łódź, Poland
¹² University of Manchester, Manchester, UK
¹³ CEA Irfu, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
¹⁴ Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
¹⁵ Horia Hulubei National Institute of Physics and Nuclear Engineering, Murele, Romania
¹⁶ Department of Physics, Faculty of Science, University of Zagreb, Zagreb, Croatia
¹⁷ University of Santiago de Compostela, Santiago, Spain
¹⁸ Agenzia nazionale per le nuove tecnologie, l’energia e lo sviluppo economico sostenibile (ENEA), Rome, Italy
¹⁹ Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Bologna, Italy
²⁰ Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste, Italy
²¹ Department of Physics, University of Trieste, Trieste, Italy
²² National Technical University of Athens, Athens, Greece
²³ Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Turin, Italy
²⁴ Department of Physics, University of Torino, Turin, Italy
²⁵ Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Bari, Italy
²⁶ Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, Perugia, Italy
²⁷ Istituto Nazionale di Astrofisica-Osservatorio Astronomico d’Abruzzo, L’Aquila, Italy
²⁸ Goethe University Frankfurt, Frankfurt, Germany
²⁹ Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
³⁰ Instituto Superior Técnico, Lisbon, Portugal
³¹ Paul Scherrer Institut (PSI), Villigen, Switzerland
³² University of Ioannina, Ioannina, Greece
³³ Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Rome, Italy
³⁴ Affiliated with an institute covered by a cooperation agreement with CERN, Geneva, Switzerland
³⁵ University of Granada, Granada, Spain
³⁶ European Commission, Joint Research Centre (JRC), Geel, Belgium
³⁷ University of York, York, UK
³⁸ TU Wien, Atominstitut, Stadionallee 2, 1020, Wien, Austria
³⁹ Japan Atomic Energy Agency (JAEA), Tokai-Mura, Japan
⁴⁰ Charles University, Prague, Czechia
⁴¹ School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
⁴² Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna, Italy
⁴³ INFN Laboratori Nazionali di Legnaro, Legnaro, Italy
⁴⁴ Dipartimento Interateneo di Fisica, Università degli Studi di Bari, Bari, Italy
⁴⁵ Consiglio Nazionale delle Ricerche, Bari, Italy
⁴⁶ Dipartimento di Fisica e Geologia, Università di Perugia, Perugia, Italy
⁴⁷ INFN Laboratori Nazionali di Frascati, Perugia, Italy
⁴⁸ Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Catania, Italy
⁴⁹ Department of Physics and Astronomy, University of Catania, Catania, Italy
⁵⁰ Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden

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Received: 29 July 2025
Accepted: 8 December 2025
Published online: 12 January 2026

Abstract

$_{}^{50}$Cr and $_{}^{53}$Cr are very relevant in criticality safety benchmarks related to nuclear reactors. The discrepancies of up to 30% between the neutron capture cross section evaluations have an important effect on the $k_{\mathit{eff}}$ and $k_{\infty }$ in criticality benchmarks particularly sensitive to chromium. In this work, the $_{}^{50,53}$Cr(n,$\gamma$) cross sections are to be determined between 1 and 100 keV with an 8–10% accuracy following the requirements of the NEA High Priority Request List (HPRL) to solve the current discrepancies. We have measured these reactions by the time-of-flight technique at the EAR1 experimental area of the n_TOF facility, using an array of four C$_6^{}$D$_6^{}$ detectors with very low neutron sensitivity. The highly-enriched samples used are significantly thinner than in previous measurements, thus minimizing the multiple-scattering effects. We have produced, and analysed with the R-matrix analysis code SAMMY, capture yields featuring 33 resonances of $_{}^{50}$Cr and 51 of $_{}^{53}$Cr with an accuracy between 5% and 9%, hence fulfilling the requirements made by the NEA. The differential and integral cross sections have been compared to previous data and evaluations. The new measured $_{}^{50,53}$Cr(n,$\gamma$) cross sections provide a valuable input for upcoming evaluations, which are deemed necessary given that the results presented herein do not support the increase in both cross sections proposed in the recent INDEN evaluation.