https://doi.org/10.1140/epja/s10050-026-01826-3
Regular Article - Experimental Physics
Measurement of the 35Cl(n, p)35S cross-section at the CERN n
TOF facility from subthermal energy to 120 keV
1
University of Granada, Granada, Spain
2
Instituto de Física Corpuscular, CSIC - Universidad de Valencia, Valencia, Spain
3
European Organization for Nuclear Research (CERN), Zurich, Switzerland
4
Universidad de Sevilla, Sevilla, Spain
5
Centro de Investigaciones Energénticas Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
6
INFN Laboratori Nazionali del Sud, Catania, Catania, Italy
7
Dipartimento di Fisica e Astronomia, Università di Catania, Catania, Italy
8
University of Lodz, Lodz, Poland
9
Institut de Physique Nucléaire, CNRS-IN2P3, Univ. Paris-Sud, Université Paris-Saclay, 91406, Orsay Cedex, France
10
TU Wien, Stadionallee 2, 1020, Atominstitut, Wien, Austria
11
CEA Irfu, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
12
Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Italy
13
Charles University, Prague, Czech Republic
14
University of Manchester, Manchester, UK
15
Department of Physics, Faculty of Science, University of Zagreb, Zagreb, Croatia
16
University of York, London, UK
17
Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, Italy
18
Dipartimento di Fisica e Geologia, Università di Perugia, Perugia, Italy
19
University of Santiago de Compostela, Santiago, Spain
20
Universitat Politècnica de Catalunya, Catalunya, Spain
21
Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Teramo, Teramo, Italy
22
Dipartimento Interateneo di Fisica, Università degli Studi di Bari, Bari, Italy
23
National Technical University of Athens, Athens, Greece
24
School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
25
Paul Scherrer Institut (PSI), Villigen, Switzerland
26
University of Ioannina, Ioannina, Greece
27
Centro Nacional de Aceleradores (CNA), Seville, Spain
28
Affiliated with an International Laboratory Covered by a Cooperation Agreement with CERN, Zurich, Switzerland
29
Goethe University, Frankfurt, Germany
30
DES, CEA Cadarache, 13108, Saint-Paul-les-Durance, France
31
Horia Hulubei National Institute of Physics and Nuclear Engineering, Magurele, Romania
32
Instituto Superior Técnico, Lisbon, Portugal
33
Japan Atomic Energy Agency (JAEA), Tokai-Mura, Japan
34
European Commission, Joint Research Centre (JRC), Geel, Belgium
35
Karlsruhe Institute of Technology, IKP, Campus North, 76021, Karlsruhe, Germany
36
Agenzia nazionale per le nuove tecnologie (ENEA), Bologna, Italy
37
Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Bologna, Italy
38
Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna, Italy
39
Istituto Nazionale di Fisica Nucleare, Sezione di Legnaro, Italy
40
Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste, Italy
41
Dipartimento di Astronomia, Università di Trieste, Trieste, Italy
42
Consiglio Nazionale delle Ricerche, Bari, Italy
43
Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
44
University of Vienna, Faculty of Physics, Vienna, Austria
45
Department of Physics, University of Basel, Basel, Switzerland
46
Centre for Astrophysics Research, University of Hertfordshire, Hertfordshire, UK
47
Bhabha Atomic Research Centre (BARC), Mumbai, India
48
Helmholtz-Zentrum Dresden-Rossendorf, Mumbai, Germany
49
Australian National University, Canberra, Australia
a
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Received:
14
November
2025
Accepted:
23
February
2026
Published online:
9
May
2026
Abstract
The 35Cl(n, p)35S reaction plays a key role in neutron dosimetry for Boron Neutron Capture Therapy, in the synthesis of the isotope 36S, whose astrophysical origin remains unresolved, and in the design of next-generation molten-salt reactors. Its relevance has motivated its inclusion in the High Priority Request List (HPRL) of NEA. The goal of this work is to determine the 35Cl(n, p)35S cross-section from thermal energy to 120 keV for the first time ever in a single measurement, thus reducing systematic uncertainties related to the normalization to the thermal value. This had been a subject of concern in previous evaluations of this reaction. We made use of the Time-of-Flight technique with microMEGAS detectors at Experimental Area 2 (EAR-2) of n_TOF facility at CERN. The 10B
7Li and 235U(n, f) reactions were used as references. Rutherford Back-scattering Spectrometry was performed at Centro Nacional de Aceleradores (CNA) in Sevilla, in order to accurately determine the masses of the irradiated samples. We obtained a thermal cross-section of 
barns. The 1/v energy dependence of the cross-section is observed up to the first resonance at 0.398 keV, the resonances up to 120 keV are analyzed and resonance parameters extracted using SAMMY. Maxwellian Averaged Cross-Section (MACS) was calculated for 
from 1 to 100 keV, and lower values compared to estimations from ENDF were found, e.g., 1.07 ± 0.20 mb at 
keV. The thermal cross-section and first two resonances are in agreement with the latest evaluation in ENDF/B-VIII.1, while remarkably lower resonance strengths were found for high energy resonances.
Communicated by Anu Kankainen.
T. Glodariu and F. Käppeler Deceased
© The Author(s) 2026
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