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The neutron time-of-flight facility n_TOF at CERN is a spallation source dedicated to measurements of neutron- induced reaction cross-sections of interest in nuclear technologies, astrophysics, and other applications. Since 2014, Experimental ARea 2 (EAR2) is operational and delivers a neutron fluence of ~ 4 · 107 neutrons per nominal proton pulse, which is ~50 times higher than the one of Experimental ARea 1 (EAR1) of ~ 8 · 105 neutrons per pulse. The high neutron flux at EAR2 results in high counting rates in the detectors that challenged the previously existing capture detection systems. For this reason, a Segmented Total Energy Detector (sTED) has been developed to overcome the limitations in the detector’s response, by reducing the active volume per module and by using a photo-multiplier (PMT) optimized for high counting rates. This paper presents the main characteristics of the sTED, including energy and time resolution, response to ¿-rays, and provides as well details of the use of the Pulse Height Weighting Technique (PHWT) with this detector. The sTED has been validated to perform neutron-capture cross-section measurements in EAR2 in the neutron energy range from thermal up to at least 400 keV. The detector has already been successfully used in several measurements at n_TOF EAR2., This work was supported in part by the I+D+i grant PGC2018- 096717-B-C21 funded by MCIN/AEI/10.13039/501100011033, by the European Commission H2020 Framework Programme project SANDA (Grant agreement ID: 847552) and by funding agencies of the n_TOF participating institutions., Article signat per 136 autors/es: V. Alcayne, D. Cano-Ott, J. Garcia, E. González-Romero, T. Martínez, A. Pérez de Rada, J. Plaza, A. Sánchez-Caballero, J. Balibrea-Correa, C. Domingo-Pardo, J. Lerendegui-Marco, A. Casanovas, F. Calviño, O. Aberle, S. Altieri, S. Amaducci, J. Andrzejewski, V. Babiano-Suarez, M. Bacak, C. Beltrami, S. Bennett, A.P. Bernardes, E. Berthoumieux, R. Beyer , M. Boromiza, D. Bosnar, M. Caamaño, M. Calviani, D.M. Castelluccio, F. Cerutti, G. Cescutti, S. Chasapoglou, E. Chiaveri, P. Colombetti, N. Colonna, P. Console Camprini, G. Cortés, M.A. Cortés-Girald, L. Cosentino, S. Dellmann, M. Di Castro, S. Di Maria, M. Diakaki, M. Dietz, R. Dressler, E. Dupont, I. Durán, Z. Eleme, S. Fargier, B. Fernández, B. Fernández-Domínguez, P. Finocchiaro, S. Fiore, V. Furman, F. García-Infantes, A. Gawlik-Ramiega, G. Gervino, S. Gilardoni, C. Guerrero, F. Gunsing, C. Gustavino, J. Heyse, W. Hillman, D.G. Jenkins, E. Jericha, A. Junghans, Y. Kadi, K. Kaperoni, G. Kaur, A. Kimura, I. Knapová, M. Kokkoris, Y. Kopatch, M. Krtička, N. Kyritsis, I. Ladarescu, C. Lederer-Woods, G. Lerner, A. Manna, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E.A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, V. Michalopoulou, P.M. Milazzo, R. Mucciola, F. Murtas, E. Musacchio-Gonzalez, A. Musumarra, A. Negret, P. Pérez-Maroto, N. Patronis, J.A. Pavón-Rodríguez, M.G. Pellegriti, J. Perkowski, C. Petrone, L. Piersanti, E. Pirovano, S. Pomp, I. Porras, J. Praena, J.M. Quesada, R. Reifarth, D. Rochman, Y. Romanets, C. Rubbia, M. Sabaté-Gilarte, P. Schillebeeckx, D. Schumann, A. Sekhar, A.G. Smith, N.V. Sosnin, M. Spelta, M.E. Stamati, A. Sturniolo, G. Tagliente, A. Tarifeño-Saldivia, D. Tarrío, P. Torres-Sánchez, E. Vagena, S. Valenta, V. Variale, P. Vaz, G. Vecchio, D. Vescovi, V. Vlachoudis, R. Vlastou, A. Wallner, P.J. Woods, T. Wright, R. Zarrella, P. Žugec., Postprint (published version)

One of the critical aspects for the accurate determination of neutron capture cross sections when combining time-of-flight and total energy detector techniques is the characterization and control of systematic uncertainties associated to the measuring devices. In this work we explore the most conspicuous effects associated to harsh count rate conditions: dead-time and pile-up effects. Both effects, when not properly treated, can lead to large systematic uncertainties and bias in the determination of neutron cross sections. In the majority of neutron capture measurements carried out at the CERN n_TOF facility, the detectors of choice are the C6D6 liquid-based either in form of large-volume cells or recently commissioned sTED detector array, consisting of much smaller-volume modules. To account for the aforementioned effects, we introduce a Monte Carlo model for these detectors mimicking harsh count rate conditions similar to those happening at the CERN n_TOF 20 m flight path vertical measuring station. The model parameters are extracted by comparison with the experimental data taken at the same facility during 2022 experimental campaign. We propose a novel methodology to consider both, dead-time and pile-up effects simultaneously for these fast detectors and check the applicability to experimental data from 197Au(n, gamma), including the saturated 4.9 eV resonance which is an important component of normalization for neutron cross section measurements., This work has been carried out in the framework of a project funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC Consolidator Grant project HYMNS, with grant agreement No. 681740). This work was supported by grant ICJ220-045122-I funded by MCIN/AEI/10.130 39/501100011033 and by European Union NextGenerationEU/PRTR. The authors acknowledge support from the Spanish Ministerio de Ciencia e Innovación under grants PID2019-104714GB-C21, PID2022- 138297NB-C21 and the funding agencies of the participating institutes. The authors acknowledge the financial support from MCIN and the European Union NextGenerationEU and Generalitat Valenciana in the call PRTR PC I+D+i ASFAE/2022/027., Article signat per 132 autors/es: J. Balibrea-Correa, J. Lerendegui-Marco, V. Babiano-Suarez, C. Domingo-Pardo, I. Ladarescu, A. Tarifeño-Saldivia, G. de la Fuente-Rosales, V. Alcayne, D. Cano-Ott, E. González-Romero, T. Martínez, E. Mendoza, A. Pérez de Rada, J. Plaza del Olmo, A. Sánchez-Caballero, A. Casanovas, F. Calviño, S. Valenta, O. Aberle, S. Altieri, S. Amaducci, J. Andrzejewski, M. Bacak, C. Beltrami, S. Bennett, A.P. Bernardes, E. Berthoumieux, R. Beyer, M. Boromiza, D. Bosnar, M. Caamaño, M. Calviani, D.M. Castelluccio, F. Cerutti, G. Cescutti, S. Chasapoglou, E. Chiaveri, P. Colombetti, N. Colonna, P. Console Camprini, G. Cortés, M.A. Cortés-Giraldo, L. Cosentino, S. Cristallo, S. Dellmann, M. Di Castro, S. Di Maria, M. Diakaki, M. Dietz, R. Dressler, E. Dupont, I. Durán, Z. Eleme, S. Fargier, B. Fernández, B. Fernández-Domínguez, P. Finocchiaro, S. Fiore, V. Furman, F. García-Infantes, A. Gawlik-Ramikega, G. Gervino, S. Gilardoni, C. Guerrero, F. Gunsing, C. Gustavino, J. Heyse, W. Hillman, D.G. Jenkins, E. Jericha, A. Junghans, Y. Kadi, K. Kaperoni, G. Kaur, A. Kimura, I. Knapová, M. Kokkoris, Y. Kopatch, M. Krtička, N. Kyritsis, C. Lederer-Woods, G. Lerner, A. Manna, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E.A. Maugeri, A. Mazzone, A. Mengoni, V. Michalopoulou, P.M. Milazzo, R. Mucciola, F. Murtas, E. Musacchio-Gonzalez, A. Musumarra, P. Negret, P. Pérez-Maroto, N. Patronis, J.A. Pavón-Rodríguez, M.G. Pellegriti, J. Perkowski, C. Petrone, E. Pirovano, S. Pomp, I. Porras, J. Praena, J.M. Quesada, R. Reifarth, D. Rochman, Y. Romanets, C. Rubbia, M. Sabaté-Gilarte, P. Schillebeeckx, D. Schumann, A. Sekhar, A.G. Smith, N.V. Sosnin, M.E. Stamati, A. Sturniolo, G. Tagliente, D. Tarrío, P. Torres-Sánchez, E. Vagena, V. Variale, P. Vaz, G. Vecchio, D. Vescovi, V. Vlachoudis, R. Vlastou, A. Wallner, P.J. Woods, T. Wright, R. Zarrella, P. Žugec, Postprint (published version)

140 Ce (n, y) is a key reaction for slow neutron-capture (s-process) nucleosynthesis due to being a bottleneck in the reaction flow. For this reason, it was measured with high accuracy (uncertainty˜5%) at the n_TOF facility, with an unprecedented combination of a high purity sample and low neutron-sensitivity detectors. The measured Maxwellian averaged cross section is up to 40% higher than previously accepted values. Stellar model calculations indicate a reduction around 20% of the s-process contribution to the Galactic cerium abundance and smaller sizeable differences for most of the heavier elements. No variations are found in the nucleosynthesis from massive stars., I.U.R. acknowledges support from the U.S. National Science Foundation (Grants No. AST 1613536, No. AST 1815403/1815767, No. AST 2205847, and No. PHY1430152—Joint Institute for Nuclear Astrophysics—Chemical Evolution of the Elements). S.C. acknowledges funding by the European Union—NextGenerationEU RFFM4C2 1.1 PRIN 2022 project “2022RJLWHN URKA” and by INAF Theory Grant “Understanding R-process & Kilonovae Aspects (URKA).” The authors acknowledge support from the MSMT of the Czech Republic, the Charles University UNCE/SCI/013 project, and by the funding agencies of the participating institutes. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this Letter., Article signat per 141 autors/es: S. Amaducci, N. Colonna, L. Cosentino, S. Cristallo, P. Finocchiaro, M. Krtička, C. Massimi, M. Mastromarco, A. Mazzone, E. A. Maugeri, A. Mengoni, I. U. Roederer, O. Straniero, S. Valenta, D. Vescovi, O. Aberle, V. Alcayne, J. Andrzejewski, L. Audouin, V. Babiano-Suarez, M. Bacak, M. Barbagallo, S. Bennett, E. Berthoumieux, J. Billowes, D. Bosnar, A. Brown, M. Busso, M. Caamaño, L. Caballero-Ontanaya, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, E. Chiaveri, G. Cortés, M. A. Cortés-Giraldo, L. A. Damone, P. J. Davies, M. Diakaki, M. Dietz, C. Domingo-Pardo, R. Dressler, Q. Ducasse, E. Dupont, I. Durán, Z. Eleme, B. Fernández-Domínguez, A. Ferrari, V. Furman, K. Göbel, R. Garg, A. Gawlik-Ramięga, S. Gilardoni, I. F. Gonçalves, E. González-Romero, C. Guerrero, F. Gunsing, H. Harada, S. Heinitz, J. Heyse, D. G. Jenkins, A. Junghans, F. Käppeler, Y. Kadi, A. Kimura, I. Knapová, M. Kokkoris, Y. Kopatch, D. Kurtulgil, I. Ladarescu, C. Lederer-Woods, H. Leeb, J. Lerendegui-Marco, S. J. Lonsdale, D. Macina, A. Manna, T. Martínez, A. Masi, P. Mastinu, E. Mendoza, V. Michalopoulou, P. M. Milazzo, F. Mingrone, J. Moreno-Soto, A. Musumarra, A. Negret, R. Nolte, F. Ogállar, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, C. Petrone, L. Piersanti, E. Pirovano, I. Porras, J. Praena, J. M. Quesada, D. Ramos-Doval, T. Rauscher, R. Reifarth, D. Rochman, C. Rubbia, M. Sabat ́e-Gilarte, A. Saxena, P. Schillebeeckx, D. Schumann, A. Sekhar, A. G. Smith, N. V. Sosnin, P. Sprung, A. Stamatopoulos, G. Tagliente, J. L. Tain, A. Tarifeño-Saldivia, L. Tassan-Got, Th. Thomas, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, P. J. Woods, T. Wright, P.Žugec, Postprint (published version)

The cross section of the 89Y(n, ¿) reaction has important implications in nuclear astrophysics and for advanced nuclear technology. Given its neutron magic number N = 50 and a consequent small neutron capture cross section, 89Y represents one of the key nuclides for the stellar s-process. It acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier elements. Moreover, it is located at the overlapping region, where both the weak and main s-process components take place. 89Y, the only stable yttrium isotope, is also used in innovative nuclear reactors. Neutron capture and transmission measurements were performed at the time-of-flight facilities n_TOF at CERN and GELINA at JRC-Geel. Resonance parameters of individual resonances were extracted from a resonance analysis of the experimental transmission and capture yields, up to a neutron incident energy of 95 keV. Even though a comparison with results reported in the literature shows differences in resonance parameters, the present data are consistent with the Maxwellian averaged cross section suggested by the astrophysical database KADoNiS., This research was funded by the European Community Seventh Framework Programme FP7/2007- 2011 under the Project CHANDA (Grant No. 605203), by the European Commission within HORIZON2020 via the EURATOM project EUFRAT for transnational access and by the funding agencies of the participating institutes., Article signat per 135 autors/es: G. Tagliente, P.M. Milazzo, C. Paradela, S. Kopecky, D. Vescovi, G. Alaerts, L.A. Damone, J. Heyse, M. Krtiˇcka, P. Schillebeeckx, A. Mengoni, R. Wynants, S. Valenta, O. Aberle, V. Alcayne, S.Amaducci, J. Andrzejewski, L. Audouin, V. Babiano-Suarez, M. Bacak, M. Barbagallo, V. Bécares, F. Beˇcváˇr, G. Bellia, E. Berthoumieux, J. Billowes, D. Bosnar, A.S. Brown, M. Busso, M. Caamaño, L. Caballero, M. Calviani, F. Calviño, D. Cano-Ott, A. Casanovas, F. Cerutti, Y.H. Chen, E. Chiaveri, N. Colonna, G.P. Cortés, M.A. Cortés-Giraldo, L. Cosentino, S. Cristallo, M. Diakaki, M. Dietz, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, Z. Eleme, B. Fernández-Domíngez, A.Ferrari, I. Ferro-Gonçalves, P. Finocchiaro, V. Furman, R. Garg, A. Gawlik, S. Gilardoni, T. Glodariu, K. Göbel32 , E. González-Romero, C. Guerrero, F. Gunsing, S. Heinitz, D.G. Jenkins, E. Jericha, Y. Kadi , F. Käppeler, A. Kimura, N. Kivel, M. Kokkoris, Y. Kopatch, D. Kurtulgil, I. Ladarescu, A.C. Larsen, C. Lederer-Woods, J. Lerendegui-Marco, S. Lo Meo, S.J. Lonsdale, M. Lugaro, D. Macina, A. Manna, T. Martínez, A. Masi, C. Massimi, P.F. Mastinu, M. Mastromarco, F. Matteucci, E. Maugeri, A. Mazzone, E. Mendoza, V. Michalopoulou, F. Mingrone, A. Musumarra, A. Negret, R. Nolte, F. Ogállar, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, L. Piersanti, I. Porras, J. Praena, J.M. Quesada, D. Radeck, D. Ramos Doval, R. Reifarth, D. Rochman, C. Rubbia, M. Sabaté-Gilarte, A. Saxena, D. Schumann, A.G. Smith, M. Spelta, N. Sosnin, A. Stamatopoulos, J.L. Tain, Z. Talip, A.E. Tarifeño-Saldivia, L. Tassan-Got, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, P.J. Woods, T.J. Wright, P. Zugec, Postprint (author's final draft)

The average energy and multiplicity of prompt y -rays from slow neutron-induced fission of 235 U have been measured using the STEFF spectrometer at the neutron time-of-flight facility n_TOF. The individual responses from 11 NaI scintillators were corrected for multiple y -ray interactions, prompt fission neutrons and background counts before being deconvolved to estimate the emitted spectrum of prompt fission y -rays. The results give an average y -ray energy ¯Ey of 1.71(5) MeV and multiplicity ¯vy of 2.66(18) considering y -rays emitted within the energy range 0.8–6.8 MeV. The n_TOF data has a slightly larger ¯Ey and smaller ¯vy than other recent measurements, however the product of the two is in agreement within quoted uncertainties., This work was supported by the UK Nuclear Data Network, the BEIS Advanced Fuel Cycle programme, the SANDA Nuclear Data Euratom Project, and the funding agencies of the participating institutes., Article signat per 124 autors/es: T. Wright, A.G.Smith, N. V. Sosnin, S. A. Bennett, P.J.Davies, A. V. Popescu, J. A. Ryan, A. Sekhar, S. Warren, O. Aberle, S. Amaducci, J. Andrzejewski, L. Audouin, M. Bacak, J. Balibrea, M. Barbagallo, F.Becvár, E. Berthoumieux, J. Billowes, D. Bosnar, A.Brown, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, R. Cardella, A. Casanovas, F. Cerutti, Y. H. Chen, E. Chiaveri, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, L. A. Damone, M. Diakaki, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, B. Fernández-Domínguez, A. Ferrari, P. Ferreira, P. Finocchiaro, V. Furman, K. Göbel, A. R. García, A. Gawlik-Ramie ̨ga, S. Gilardoni, T. Glodariu, I. F. Gonçalves, E. González-Romero, E. Griesmayer, C. Guerrero, F. Gunsing, H. Harada, S. Heinitz, J. Heyse, D. G. Jenkins, E. Jericha, F. Käppeler, Y. Kadi, A. Kalamara, P. Kavrigin, A. Kimura, N.Kivel, M. Kokkoris, M.Krtiˇcka, D. Kurtulgil, E. Leal-Cidoncha, C. Lederer-Woods, H. Leeb, J. Lerendegui-Marco, S.LoMeo, S. J. Lonsdale, D. Macina, A. Manna, J. Marganiec, T. Martínez, A.Masi, C. Massimi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, P. M. Milazzo, F. Mingrone, A. Musumarra, A. Negret, R.Nolte, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, I. Porras, J. Praena, J. M. Quesada, D. Radeck, T. Rauscher, R. Reifarth, C. Rubbia, M. Sabaté-Gilarte, A. Saxena, P. Schillebeeckx, D. Schumann, P. Sedyshev, A. Stamatopoulos, G. Tagliente, J.L.Tain, A. Tarifeño-Saldivia, L. Tassan-Got, S. Valenta, G. Vannini, V. Variale, P.Vaz, A. Ventura, V. Vlachoudis, R.Vlastou, A. Wallner, C. Weiss, P. J. Woods, P. Žugec., Postprint (published version)

This is an Accepted Manuscript, the final version can be found at: https://journals.aps.org/prc/abstract/10.1103/PhysRevC.108.064307 ©2024 American Physical Society., ß-delayed ¿-neutron spectroscopy has been performed on the decay of A = 84 to 87 gallium isotopes at the RI-beam Factory at the RIKEN Nishina Center using a high-efficiency array of 3He neutron counters (BRIKEN). ß-2n-¿ events were measured in the decays of all of the four isotopes for the first time, which is direct evidence for populating the excited states of two-neutron daughter nuclei. Detailed decay schemes with the ¿ branching ratios were obtained for these isotopes and the neutron emission probabilities (Pxn) were updated from the previous study. Hauser-Feshbach statistical model calculations were performed to understand the experimental branching ratios. We found that the P1n and P2n values are sensitive to the nuclear level densities of 1n daughter nuclei and showed that the statistical model reproduced the P2n/P1n ratio better when experimental levels + shell-model level densities fit by the Gilbert-Cameron formula were used as the level-density input. We also showed the neutron and ¿ branching ratios are sensitive to the ground-state spin of the parent nucleus. Our statistical model analysis suggested J = 3 for the unknown ground-state spin of the odd-odd nucleus, 86Ga, from the I¿(4+ ¿ 2 +)/I¿(2+ ¿ 0 +) ratio of 84Ga and the P2n/P1n ratio. These results show the necessity of detailed understanding of the decay scheme, including data from neutron spectroscopy, in addition to ¿ measurements of the multi-neutron emitters., This experiment was performed at the RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo. This research was sponsored in part by the Office of Nuclear Physics, U.S. Department of Energy under Award No. DE-FG02-96ER40983 (UTK) and DE-AC05-00OR22725 (ORNL), No. DE-SC0016988 (TTU) and by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through DOE Award No. DE-NA0002132. This work was supported by National Science Foundation under Grants No. PHY-1430152 (JINA Center for the Evolution of the Elements), No. PHY-1565546 (NSCL), and No. PHY-1714153 (Central Michigan University). This work was partially funded by the Polish National Science Center under Contracts No. UMO2015/18/E/ST2/00217, 2020/39/B/ST2/02346, and No. 2017/01/X/ST2/01144. This work was also supported by JSPS KAKENHI (Grants No. 14F04808, No. 17H06090, No. 25247045, 20H05648, 22H04946 and No. 19340074), by the UK Science and Technology Facilities Council, by NKFIH (NN128072), by Spanish Ministerio de Economia y Competitividad grants (FPA2011-06419, FPA2011- 28770-C03-03, FPA2014-52823-C2-1-P, FPA2014-52823- C2-2-P, SEV-2014-0398, IJCI-2014-19172), by Generarlitat Valenciana regional grant PROMETEO/2019/007, by European Commission FP7/EURATOM Contract No. 605203, by the UK Science and Technology Facilities Council Grant No. ST/N00244X/1, ST//P004598/1, and ST/V001027/1 by the National Research Foundation (NRF) in South Korea (No. 2016K1A3A7A09005575, No. 2015H1A2A1030275) and by the Natural Sciences and Engineering Research Council of Canada (NSERC) via the Discovery Grants SAPIN-2014-00028 and RGPAS 462257-2014. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada. The author, R.Y. acknowledges support from JSPS KAKENHI 22K14053. G.G.K. acknowledges support from the Janos Bolyai research fellowship of the Hungarian Academy of Sciences. M.W.- C. acknowledges support from the Pol, Article signat per 72 autors/es: R. Yokoyama, R. Grzywacz, B. C. Rasco, N. Brewer, K. P. Rykaczewski, I. Dillmann, J. L. Tain, S. Nishimura, D. S. Ahn, A. Algora, J. M. Allmond, J. Agramunt, H. Baba, S. Bae, C. G. Bruno, R. Caballero-Folch, F. Calvino, P. J. Coleman-Smith, G. Cortes, T. Davinson, C. Domingo-Pardo, A. Estrade, N. Fukuda, S. Go, C. J. Griffin, J. Ha, O. Hall, L. J. Harkness-Brennan, J. Heideman, T. Isobe, D. Kahl, M. Karny, T. Kawano, L. H. Khiem, T. T. King, G. G. Kiss, A. Korgul, S. Kubono, M. Labiche, I. Lazarus, J. Liang, J. Liu, G. Lorusso, M. Madurga, K. Matsui, K. Miernik, F. Montes, A. I. Morales, P. Morrall, N. Nepal, R. D. Page, V. H. Phong, M. Piersa-Siłkowska, M. Prydderch, V. F. E. Pucknell, M. M. Rajabali, B. Rubio, Y. Saito, H. Sakurai, Y. Shimizu, J. Simpson, M. Singh, D. W. Stracener, T. Sumikama, H. Suzuki, H. Takeda, A. Tarifeño-Saldivia, S. L. Thomas, A. Tolosa-Delgado, M. Wolińska-Cichocka, P. J. Woods, and X. X. Xu, Postprint (published version)

The version of record of this article, first published in [The Europen Physics Journal A], is available online at Publisher’s website: http://dx.doi.org/10.1140/epja/s10050-022-00876-7, This article presents a few selected developments and future ideas related to the measurement of (n,¿) data of astrophysical interest at CERN n_TOF. The MC-aided analysis methodology for the use of low-efficiency radiation detectors in time-of-flight neutron-capture measurements is discussed, with particular emphasis on the systematic accuracy. Several recent instrumental advances are also presented, such as the development of total-energy detectors with ¿ - ray imaging capability for background suppression, and the development of an array of small-volume organic scintillators aimed at exploiting the high instantaneous neutron-flux of EAR2. Finally, astrophysics prospects related to the intermediate i neutron-capture process of nucleosynthesis are discussed in the context of the new NEAR activation area, Peer Reviewed, Article escrit per 139 auors/autores C. Domingo-Pardo, V. Babiano-Suarez, J. Balibrea-Correa, L. Caballero, I. Ladarescu, J. Lerendegui-Marco, J. L. Tain, A. Tarifeño-Saldivia, O. Aberle, V. Alcayne, S. Altieri, S. Amaducci, J. Andrzejewski, M. Bacak, C. Beltrami, S. Bennett, A. P. Bernardes, E. Berthoumieux, M. Boromiza, D. Bosnar, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, G. Cescutti, S. Chasapoglou, E. Chiaveri, N. M. Chiera, P. Colombetti, N. Colonna, P. Console Camprini, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, S. Cristallo, S. Dellmann, M. Di Castro, S. Di Maria, M. Diakaki, M. Dietz, R. Dressler, E. Dupont, I. Durán, Z. Eleme, S. Fargier, B. Fernández, B. Fernández-Domínguez, P. Finocchiaro, S. Fiore, F. García-Infantes, A. Gawlik-Ramięga , G. Gervino, S. Gilardoni, E. González-Romero, C. Guerrero, F. Gunsing, C. Gustavino, J. Heyse, W. Hillman, D. G. Jenkins, E. Jericha, A. Junghans, Y. Kadi, K. Kaperoni, F. Käppeler, G. Kaur, A. Kimura, I. Knapová, U. Köster, M. Kokkoris, M. Krtička, N. Kyritsis, C. Lederer-Woods, G. Lerner, A. Manna, T. Martínez, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, P. M. Milazzo, I. Mönch, R. Mucciola, F. Murtas, E. Musacchio-Gonzalez, A. Musumarra, A. Negret, A. Pérez de Rada, P. Pérez-Maroto, N. Patronis, J. A. Pavón-Rodríguez, M. G. Pellegriti, J. Perkowski, C. Petrone, E. Pirovano, J. Plaza, S. Pomp, I. Porras, J. Praena, J. M. Quesada, R. Reifarth, D. Rochman, Y. Romanets, C. Rubbia, A. Sánchez, M. Sabaté-Gilarte, P. Schillebeeckx, D. Schumann, A. Sekhar, A. G. Smith, N. V. Sosnin, M. Stamati, A. Sturniolo, G. Tagliente, D. Tarrío, P. Torres-Sánchez, J. Turko, S. Urlass, E. Vagena, S. Valenta, V. Variale, P. Vaz, G. Vecchio, D. Vescovi, V. Vlachoudis, R. Vlastou, T. Wallner, P. J. Woods, T. Wright, R. Zarrella, P. Žugec, Postprint (published version)

At the RIKEN Nishina Center, exotic neutron-rich isotopes of Ba, La, Ce, Pr, and Nd were measured. This work reports their half-lives (T1/2) and ß-delayed neutron-emission probabilities (Pxn). The setup consisted of the BigRIPS in-flight separator for particle identification, the Advanced Implanta- tion Detector Array (AIDA) for ions and ß detection, and the BRIKEN neutron counter for neutron detection. Using this arrangement, 4 new T1/2 and 14 new P1n were measured. Furthermore, 38 T1/2 and 2 P1n values were remeasured, decreasing the uncertainties for some of them. In addition to improving predic- tions of nucleosynthesis models that describe the production of the rare-earth peak at A~160 via the r-process, these additional experimental data should help to constrain theoretical models for calculations of T1/2 and Pxn in this region., This work has been supported by the Spanish Ministerio de Economía y Competitividad un- der Grants nos. FPA2014-52823-C2-1-P, FPA2014-52823-C2-2-P, FPA2017-83946-C2-1-P, FPA2017-83946-C2-2-P and grants from Ministerio de Ciencia e Innovacion nos PID2019- 104714GB-C21, PID2019-104714GB-C22. It was also supported by NKFIH (NN128072) and by the ÚNKP-22-2 and ÚNKP-22-3 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and In- novation Fund (Project numbers: ÚNKP-22-2-I-DE-75; ÚNKP-22-3-II- DE-132)., Article signat per 61 autors/es: M. Pallàs, A. Tarifeño-Saldivia, G. G. Kiss, J. L. Tain, A. Tolosa- Delgado, A. Vitéz-Sveiczer, F. Calviño, J. Agramunt, P. Aguilera, A. Algora, J. M. Allmond, H. Baba, N. T. Brewer, R. Caballero-Folch, P. J. Coleman-Smith, G. Cortes, T. Davinson, I. Dillmann, C. Domingo-Pardo, A. Estrade, N. Fukuda, S. Go, C. J. Griffin, R. K. Grzywacz, O. Hall, L. J. Harkness-Brennan, T. Isobe, D. Kahl, T. T. King, A. Korgul, S. Kovács, S. Kubono, M. Labiche, J. Liu, M. Madurga, K. Miernik, F. Molina, N. Mont-Geli, A. I. Morales, E. Nácher, A. Navarro, N. Nepal, S. Nishimura, M. Piersa- Silkowska, V. Phong, B. C. Rasco, J. Romero-Barrientos, B. Rubio, K. P. Rykaczewski, Y. Saito, H. Sakurai, Y. Shimizu, M. Singh, T. Sumikama, H. Suzuki, T. N. Szegedi, H. Takeda, K. Wang, M. Woli´nska-Cichocka, P. J. Woods, and R. Yokoyama for the BRIKEN collaboration., Postprint (published version)

Half-lifes (T1/2) of exotic neutron-rich isotopes of Ba, La, Ce, Pr, and Nd were measured at the RIKEN Nishina Center. The experimental setup consisted of the BigRIPS in-flight separator for ion selection identification, the Advance Implantation Detector Array (AIDA) for ions and ß detection, and the BRIKEN detector for neutron counting. Using this setup, 4 new T1/2 have been measured for the first time, and 38 T1/2 have been remeasured with improved precision in several cases. These new experimental data should help to constrain theoretical models for calculations of T1/2. The status of the experimental analysis and preliminary results are provided in this contribution., This work has been supported by the Spanish Ministerio de Economía y Competitividad under Grants. FPA2014- 52823-C2-1-P, FPA2014-52823-C2-2-P, FPA2017-83946- C2-1-P, FPA2017-83946-C2-2-P and grants from Ministerio de Ciencia e Innovacion PID2019-104714GB-C21, PID2019-104714GB-C22. Supported by Generalitat Valenciana regional grant PROMETEO/2019/007. Supported by European Union FEDER funds. It also has been supported by NKFIH (NN128072)., Article signat per 61 autors/es: M. Pallàs, A. Tarifeño-Saldivia, G. G. Kiss, J. L. Tain, A. Tolosa-Delgado, A. Vitéz- Sveiczer, F. Calviño, J. Agramunt, P. Aguilera, A. Algora, J. M. Allmond, H. Baba, N. T. Brewer, R. Caballero-Folch, P. J. Coleman-Smith, G. Cortes, T. Davinson, I. Dillmann, C. Domingo-Pardo, A. Estrade, N. Fukuda, S. Go, C. J. Griffin, R. K. Grzywacz, O. Hall, L. J. Harkness-Brennan, T. Isobe, D. Kahl, T. T. King, A. Korgul, S. Kovács, S. Kubono, M. Labiche, J. Liu, M. Madurga, K. Miernik, F. Molina, N. Mont-Geli, A. I. Morales, E. Nácher, A. Navarro, N. Nepal, S. Nishimura, M. Piersa-Silkowska, V. Phong, B. C. Rasco, J. Romero-Barrientos, B. Rubio, K. P. Rykaczewski, Y. Saito, H. Sakurai, Y. Shimizu, M. Singh, T. Sumikama, H. Suzuki, T. N. Szegedi, H. Takeda, K. Wang, M. Woli´nska-Cichocka, P. J. Woods, and R. Yokoyama for the BRIKEN collaboration., Postprint (published version)

The 77Se(n,¿) reaction is of importance for 77Se abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the 77Se radiative neutron capture cross section at the Neutron Time-of-Flight facility at CERN. Resonance capture kernels were derived up to 51 keV and cross sections up to 200 keV. Maxwellian-averaged cross sections were calculated for stellar temperatures between kT=5keV and kT=100keV, with uncertainties between 4.2% and 5.7%. Our results lead to substantial decreases of 14% and 19% in 77Se abundances produced through the slow neutron capture process in selected stellar models of 15M¿ and 2M¿, respectively, compared to using previous recommendation of the cross section., This work was supported by the UK Science and Facilities Council (ST/M006085/1), the MSMT of the Czech Republic, the Charles University UNCE/SCI/013 project, the European Research Council ERC-2015-StG No. 677497, and by the funding agencies of the participating institutes. In line with the principles that apply to scientific publishing and the CERN policy in matters of scientific publications, the n_TOF Col- laboration recognizes the work of Y. Kopatch and V. Furman (JINR, Russia), who have contributed to the experiment used to obtain the results described in this paper., Article signat per 131 autors/es: N. V. Sosnin , C. Lederer-Woods, M. Krtiˇcka, R. Garg, M. Dietz, M. Bacak, M. Barbagallo, U. Battino, S. Cristallo, L. A. Damone, M. Diakaki, S. Heinitz, D. Macina, M. Mastromarco, F. Mingrone, A. St. J. Murphy, G. Tagliente, S. Valenta, D. Vescovi, O. Aberle, V. Alcayne, S. Amaducci, J. Andrzejewski, L. Audouin, V. Bécares, V. Babiano-Suarez, F. Beˇcváˇr, G. Bellia, E. Berthoumieux, J. Billowes, D. Bosnar, A. Brown, M. Busso, M. Caamaño, L. Caballero, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, Y. H. Chen, E. Chiaveri, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, Z. Eleme, B. Fernández-Domínguez, A. Ferrari, P. Finocchiaro, K. Göbel, A. Gawlik-Rami˛ega, S. Gilardoni, T. Glodariu, I. F. Gonçalves, E. González-Romero, C. Guerrero, F. Gunsing, H. Harada, J. Heyse, D. G. Jenkins, E. Jericha, F. Käppeler, Y. Kadi, A. Kimura, N. Kivel, M. Kokkoris, D. Kurtulgil, I. Ladarescu, H. Leeb, J. Lerendegui-Marco, S. Lo Meo, S. J. Lonsdale, A. Manna, T. Martínez, A. Masi, C. Massimi, P. Mastinu, F. Matteucci, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, V. Michalopoulou, P. M. Milazzo, A. Musumarra, A. Negret, R. Nolte, F. Ogállar, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, L. Piersanti, I. Porras, J. Praena, J. M. Quesada, D. Radeck, D. Ramos-Doval, T. Rauscher, R. Reifarth, D. Rochman, C. Rubbia, M. Sabaté-Gilarte, A. Saxena, P. Schillebeeckx, D. Schumann, A. G. Smith, A. Stamatopoulos, J. L. Tain, T. Talip, A. Tarifeño-Saldivia, L. Tassan-Got, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, P. J. Woods,T. Wright, and P. Žugec., Postprint (published version)

Background: The 14N(n,p)14C 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 14N 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 14N(n,p)14C 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. 10B(n,a)7Li and 235U(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 14N(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., We thank Mr. Wilhelmus Vollenberg for the preparation of the adenine samples. This work was partially supported by Spanish Ministerio de Ciencia e Innovación (PID2020- 117969RB-I00), Junta de Andalucía (FEDER Andalucia 2014-2020) Projects No. P20-00665 and No. B-FQM-156- UGR20. This work was also supported by the UK Science and Facilities Council (ST/M006085/1, ST/P004008/1), by the European Research Council ERC-2015-StG No. 677497, and by the funding agencies of the n_TOF participating in- stitutes. P.T. acknowledges support from the Spanish Ministry of Science, Innovation and Universities under the FPU Grant No. FPU17/02305., Article signat per 132 autors/es: 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 Beˇcváˇr, 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, Kathrin Göbel, Ruchi Garg, Aleksandra Gawlik-Ramiega, Benoit Geslot, Simone Gilardoni, Tudor Glodariu, Isabel Gonçalves, Enrique González-Romero, Carlos Guerrero, Frank Gunsing, Hideo Harada, Stephan Heinitz, Jan Heyse, David Jenkins, Erwin Jericha, Franz Käppeler, Yacine Kadi, Atsushi Kimura, Niko Kivel, Michael Kokkoris, Yury Kopatch, Milan Krtiˇcka, Deniz Kurtulgil, Ion Ladarescu, Helmut Leeb, Jorge Lerendegui-Marco, Sergio Lo Meo, Sarah-Jane Lonsdale, Daniela Macina, Alice Manna, Trinitario Martínez, Alessandro Masi, Cristian Massimi, Pierfrancesco Mastinu, Mario Mastromarco, Francesca Matteucci, Emilio-Andrea Maugeri, Annamaria Mazzone, Emilio Mendoza, Alberto Mengoni, Veatriki Michalopoulou, Paolo Maria Milazzo, Federica Mingrone, Agatino Musumarra, Alexandru Negret, Ralf Nolte, Francisco Ogállar, Andreea Oprea, Nikolas Patronis, Andreas Pavlik, Jarosław Perkowski, Luciano Persanti, José-Manuel Quesada, Désirée Radeck, Diego Ramos-Doval, Thomas Rauscher, René Reifarth, Dimitri Rochman, Carlo Rubbia, Alok Saxena, Peter Schillebeeckx, Dorothea Schumann, Gavin Smith, Nikolay Sosnin, Athanasios Stamat, Postprint (published version)

(English) Thin targets, in form of foils, stripes or wires, are widely used in beam instrumentation to measure various beam parameters, such as intensity, position and size. All these monitors can differ in geometry and material. Depending on beam parameters such as intensity, energy, transverse and longitudinal size, the detector can suffer thermomechanical stresses. This can potential ly perturb the measurement accuracy and degrade the integrity of the detector. The core of this c ontribution presents the development of a finite finite-difference model, developed to simulate the particle particle-detector interactions and predict the detector material heating and damage. This work has been mainly performed in the context of LINAC4, which is the first accelerator at CERN's accelerator chain. Some other facilities (CERN PS Booster, CERN SPS, GSI facility) will also be mentioned in this document. However, the majority of the studies and conclusions will refer to the energy range (45 keV - 160 MeV) an d detector types available at LINAC4 (SEM grids and wire scanners). To understand the purpose, functionality and limitation of thin target detectors, this document introduces the basic principles of transverse beam dynamics and beam matter interactions, focusing on processes such as: energy deposition, secondary electron emission (SEE), electron backscattering, etc. The thermal model implemented during this work (PyTT) to simulate the thermal evolution of thin target detectors is presented and detailed di scussed. To assess the reliability of the simulated results, an experiment performed at LINAC4 is presented. This experiment heavily relied on the theory of thermionic emission to indirectl indirectly measure the temperature of the detectors during operation. The performance of the simulation tool is discussed, in terms of results sensitivity to parameter uncertainty. Uncertainties in material parameters, such as the emissivity, yield uncertainties in simulation results, (Español) Blancos finos, en forma de laminas, bandas o hilos, son comúnmente usados en el mundo de la instrumentación de haces para medir varios parámetros del haz de partículas, por ejemplo la intensidad, posición y medida. Dependiendo de los parámetros del haz, tales como la intensidad, la energía, el tamaño longitudinal y transversal, los detectores pueden sufrir un grave estrés termodinámico. Esto puede potencialmente perturbar la precisión de las medidas y degradar la integridad del detector. La parte principal de esta contribución presenta la implementación de un modelo basado en diferencias finitas, desarrollado para simular las interacciones entre las partículas y el detector y predecir el calentamiento del material y el daño. Este trabajo ha sido realizado principalmente en el contexto del LINAC4, que es el primer acelerador en la cadena de aceleradores del CERN. Algunas otras instalaciones (CERN PS Booster, CERN SPS, GSI ). También se mencionan en este documento. Sin embargo, la mayoría de los estudios y las conclusiones se refieren al rango de energías ( 45 keV - 160 MeV) y tipos de detectores disponibles en el LINAC4 (SEM grids y Wire Scanners). Para entender el propósito, la funcionalidad y las limitaciones de los detectores de blanco fino, este documento introduce los principios básicos de la dinámica transversal de haces y las interacciones haz-materia, prestando especial atención a procesos como: Deposición de energía, emisión secundaria de electrones (SEE), back-scattering de electrones, etc. El modelo termico implementados durante este trabajo (PyTT) simula la evolución térmica de un detector fino y esta discutido en detalle en este documento. Para comprobar la precisión de las simulaciones, se presenta un experimento realizado en el LINAC4. La temperatura de los detectores se pudo medir de forma indirecta gracias a la teoría de emision de electrones thermoionicos. El rendimiento de las simulaciones se discute en terminos de sensitividad y incertid, Postprint (published version)

The neutron-induced fission cross section of 230 Th has been measured at the neutron time-of-flight facility n_TOF located at CERN. The experiment was performed at the experimental area EAR-1 with a neutron flight path of 185 m, using Micromegas detectors for the detection of the fission fragments. The 230 Th(n, f ) cross section was determined relative to the 235 U(n, f ) one, covering the energy range from the fission threshold up to 400 MeV. The results from the present work are compared with existing cross-section datasets and the observed discrepancies are discussed and analyzed. Finally, using the code EMPIRE 3.2.3 a theoretical study, based on the statistical model, was performed leading to a satisfactory reproduction of the experimental results with the proper tuning of the respective parameters, while for incident neutron energy beyond 200 MeV the fission of 230 Th was described by Monte Carlo simulations., This project received funding from the Euratom “Support safe operation of nuclear systems” program 2014–2018 under Grant Agreement No. 847552 (SANDA) and by the funding agencies of the participating institutes. This research is imple- mented through the IKY scholarships program and cofinanced by the European Union (European Social Fund ’ESF) and Greek national funds through the action entitled “Reinforce- ment of Postdoctoral Researchers - 2nd call (MIS 5033021)”, in the framework of the Operational Programme “Human Resources Development Program, Education and Lifelong Learning” of the National Strategic Reference Framework., Article signat per 137 autors/es: V. Michalopoulou, A. Stamatopoulos, M. Diakaki, A. Tsinganis, R. Vlastou, M. Kokkoris, N. Patronis, Z. Eleme, D. Macina, L. Tassan-Got, N. Colonna, E. Chiaveri, A. Ventura, P. Schillebeeckx, J. Heyse, G. Sibbens, G. Alaerts, A. Borella, A. Moens, D. Vanleeuw, O. Aberle, V. Alcayne, S. Amaducci, J. Andrzejewski, L. Audouin, V. Babiano-Suarez, M. Bacak, M. Barbagallo, S. Bennett, E. Berthoumieux, J. Billowes, D. Bosnar, A. Brown, M. Busso, M. Caamaño, L. Caballero, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, S. Cristallo, L. A. Damone, P. J. Davies, M. Dietz, C. Domingo-Pardo, R. Dressler, Q. Ducasse, E. Dupont, I. Durán, B. Fernández-Domínguez, A. Ferrari, P. Finocchiaro, V. Furman, K. Göbel, R. Garg, A. Gawlik-Ramiega, S. Gilardoni, I. F. Gonçalves, E. González-Romero, C. Guerrero, F. Gunsing, H. Harada, S. Heinitz, D. G. Jenkins, A. Junghans, F. Käppeler, Y. Kadi, A. Kimura, I. Knapová, Y. Kopatch, M. Krticka, D. Kurtulgil, I. Ladarescu, C. Lederer-Woods, H. Leeb, J. Lerendegui-Marco, S. J. Lonsdale, A. Manna, T. Martínez, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, P. M. Milazzo, F. Mingrone, J. Moreno-Soto, A. Musumarra, A. Negret, R. Nolte, F. Ogállar, A. Oprea, A. Pavlik, J. Perkowski, C. Petrone, L. Piersanti, E. Pirovano, I. Porras, J. Praena, J. M. Quesada, D. Ramos-Doval, T. Rauscher, R. Reifarth, D. Rochman, Y. Romanets, C. Rubbia, M. Sabaté-Gilarte, A. Saxena, D. Schumann, A. Sekhar, A. G. Smith, N. V. Sosnin, P. Sprung, G. Tagliente, J. L. Tain, A. Tarifeño-Saldivia, Th. Thomas, P. Torres-Sánchez, J. Ulrich, S. Urlass, S. Valenta, G. Vannini, V. Variale, P. Vaz, D. Vescovi, V. Vlachoudis, A. Wallner, P. J. Woods, T. Wright, and P. Žugec., Postprint (published version)

The neutron-induced fission cross sections of 232 Th and 233 U were measured relative to 235 U in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of 232 Th , and from 0.7 eV in case of 233 U ), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of 233 U , previous results available in EXFOR, whereas in the case of 232 Th these data were obtained from our measurement, using PPACs and targets tilted 45 ° with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL + + and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those ( p , f ) data with our ( n , f ) data on 232 Th and 233 U and on other isotopes studied earlier at n_TOF using the same experimental setup., Peer Reviewed, Article escrit per 81 autors/autores: D. Tarrío , L. Tassan-Got, I. Duran, L. S. Leong, C. Paradela, L. Audouin, E. Leal-Cidoncha, C. Le Naour, M. Caamaño, A. Ventura, S. Altstadt, J. Andrzejewski, M. Barbagallo, V. Bécares, F. Becvá ˇ ˇr,F. Belloni, E. Berthoumieux, J. Billowes, V. Boccone, D. Bosnar, M. Brugger, M. Calviani, F. Calviño, D. Cano-Ott, C. Carrapiço, F. Cerutti, E. Chiaveri,M. Chin, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, M. Diakaki, C. Domingo-Pardo, N. Dzysiuk, C. Eleftheriadis, A. Ferrari, K. Fraval, S. Ganesan, A. R. García, G. Giubrone, M. B. Gómez-Hornillos, I. F. Gonçalves, E. González-Romero,E. Griesmayer, C. Guerrero, F. Gunsing, P. Gurusamy, D. G. Jenkins, E. Jericha, Y. Kadi, F. Käppeler,† D. Karadimos, P. Koehler, M. Kokkoris, M. Krticka, J. Kroll, C. Langer, C. Lederer, H. Leeb, R. Losito, A. Manousos, J. Marganiec, T. Martínez, C. Massimi, P. F. Mastinu,M. Mastromarco, M. Meaze, E. Mendoza, A. Mengoni, P. M. Milazzo, F. Mingrone, M. Mirea,,† W. Mondalaers, A. Pavlik, J. Perkowski, A. Plompen, J. Praena, J. M. Quesada, T. Rauscher, R. Reifarth, A. Riego, M. S. Robles, F. Roman, C. Rubbia, R. Sarmento, P. Schillebeeckx,S. Schmidt, G. Tagliente, J. L. Tain, A. Tsinganis, S. Valenta, G. Vannini, V. Variale, P. Vaz, R. Versaci, M. J. Vermeulen, V. Vlachoudis, R. Vlastou,A. Wallner, T. Ware, M. Weigand, C. Weiß, T. J. Wright, P. Žugec, Postprint (published version)

Neutron capture cross section measurements in time-of-flight facilities are usually performed by detecting the prompt ¿-rays emitted in the capture reactions. One of the difficulties to be addressed in these measurements is that the emitted ¿-rays may change with the neutron energy, and therefore also the detection efficiency. To deal with this situation, many measurements use the so called Total Energy Detection (TED) technique, usually in combination with the Pulse Height Weighting Technique (PHWT). With it, it is sought that the detection efficiency depends only on the total energy of the ¿-ray cascade, which does not vary much with the neutron energy. This technique was developed in the 1960s and has been used in many neutron capture experiments to date. One of the requirements of the technique is that ¿-ray detectors have a low efficiency. This has meant that the PHWT has been used with experimental setups with low detection efficiencies. However, this condition does not have to be fulfilled by the experimental system as a whole. The main goal of this work is to show that it is possible to measure with a high efficiency detection system that uses the PHWT, and how to analyze the measured data, Peer Reviewed, Postprint (published version)

Stellar nucleosynthesis of elements heavier than iron is driven by neutron capture processes. Zr92 is positioned at a strategic point along the slow nucleosynthesis path, given its proximity to the neutron magic number N=50 and its position at the matching region between the weak and main slow processes. Purpose: In parallel with recent improved astronomical data, the extraction of accurate Maxwellian averaged cross sections (MACSs) derived from a more complete and accurate set of resonance parameters should allow for a better understanding of the stellar conditions at which nucleosynthesis takes place. Methods: Transmission and capture cross section measurements using enriched Zr92 metallic samples were performed at the time-of flight facilities GELINA of JRC-Geel (BE) and n_TOF of CERN (CH). The neutron beam passing through the samples was investigated in transmission measurements at GELINA using a Li-glass scintillator. The ¿ rays emitted during the neutron capture reactions were detected by C6D6 detectors at both GELINA and n_TOF. Results: Resonance parameters of individual resonances up to 81 keV were extracted from a combined resonance shape analysis of experimental transmissions and capture yields. For the majority of the resonances the parity was determined from an analysis of the transmission data obtained with different sample thicknesses. Average resonance parameters were calculated. Conclusions: Maxwellian averaged cross sections were extracted from resonances observed up to 81 keV. The MACS for kT=30keV is fully consistent with experimental data reported in the literature. The MACSs for kT¿15keV are in good agreement with those derived from the ENDF/B-VIII.0 library and recommended in the KADoNiS database. For kT higher than 30 keV differences are observed. A comparison with MACSs obtained with the cross sections recommended in the JEFF-3.3 and JENDL-4.0 libraries shows discrepancies even for kT¿15keV., Peer Reviewed, Article escrit per 116 Autors/autores : Tagliente, G.; Kopecky, S.; Heyse, J.; Krtička, M.; Massimi, C.; Mengoni, A.; Milazzo, P. M.; Plompen, A. J. M.; Schillebeeckx, P.; Valenta, S.; Wynants, R.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Barbagallo, M.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviño, F.; Calviani, M.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Cristallo, S.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Durán, I.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Furman, V.; Göbel, K.; Gómez-Hornillos, M. B.; Ganesan, S.; García, A. R.; Giubrone, G.; Gonçalves, I. F.; González-Romero, E.; Goverdovski, A¸ E. Griesmayer¸C. Guerrero; F. Gunsing; T. Heftrich; A. Hernández-Prieto; E. Jericha; F. Käppeler, Y. Kadi, D. Karadimos, T. Katabuchi, V. Ketlerov, V. Khryachkov, N. Kivel, M. Kokkoris, J. Kroll, C. Lampoudis, C. Langer, E. Leal-Cidoncha, C. Lederer, H. Leeb, L. S. Leong, R. Losito, M. Lugaro, A. Mallick, A. Manousos, J. Marganiec, T. Martínez, P. Mastinu, M. Mastromarco, E. Mendoza, F. Mingrone, M. Mirea, C. Paradela, A. Pavlik, J. Perkowski, J. Praena, J. M. Quesada, T. Rauscher, R. Reifarth, A. Riego-Perez, M. Robles, C. Rubbia, J. A. Ryan, M. Sabaté-Gilarte, R. Sarmento, A. Saxena, S. Schmidt, D. Schumann, P. Sedyshev, J. L. Tain, A. Tarifeño-Saldivia, D. Tarrío, L. Tassan-Got, A. Tsinganis, G. Vannini, V. Variale, P. Vaz, A. Ventura, M. J. Vermeulen, D. Vescovi, V. Vlachoudis, R. Vlastou,21 A. Wallner, T. Ware, M. Weigand, C. Weiss, T. Wright, P. Žugec, Postprint (published version)

The version of record os available online at:https://doi.org/10.1140/epja/s10050-022-00878-5, Neutron capture reaction cross sections on 74Ge are of importance to determine 74Ge production during the astrophysical slow neutron capture process. We present new resonancedataon74Ge(n,¿)reactionsbelow70keVneutron energy. We calculate Maxwellian averaged cross sections, combining our data below 70 keV with evaluated cross sections at higher neutron energies. Our stellar cross sections are in agreement with a previous activation measurement performed at Forschungszentrum Karlsruhe by Marganiec et al., once their data has been re-normalised to account for an update in the reference cross section used in that experiment, Peer Reviewed, Article escrit per 123 autors/autores C. Lederer-Woods, O. Aberle, J. Andrzejewski, L. Audouin, V. Bécares, M. Bacak, J. Balibrea, M. Barbagallo, S. Barros, U. Battino, F. Bečvář, C. Beinrucker, E. Berthoumieux, J. Billowes, D. Bosnar, M. Brugger, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, R. Cardella, A. Casanovas, D. M. Castelluccio, F. Cerutti, Y. H. Chen, E. Chiaveri, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, L. A. Damone, M. Diakaki, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, B. Fernández-Domínguez, A. Ferrari, P. Ferreira, P. Finocchiaro, V. Furman, K. Göbel, A. R. García, A. Gawlik-Ramięga, T. Glodariu, I. F. Gonçalves, E. González-Romero, A. Goverdovski, E. Griesmayer, C. Guerrero, F. Gunsing, H. Harada, T. Heftrich, S. Heinitz, J. Heyse, D. G. Jenkins, E. Jericha, F. Käppeler, Y. Kadi, T. Katabuchi, P. Kavrigin, V. Ketlerov, V. Khryachkov, A. Kimura, N. Kivel, M. Kokkoris, M. Krtička, E. Leal-Cidoncha, H. Leeb, J. Lerendegui-Marco, S. Lo Meo, S. J. Lonsdale, R. Losito, D. Macina, J. Marganiec, T. Martínez, C. Massimi, P. Mastinu, M. Mastromarco, F. Matteucci, E. A. Maugeri, E. Mendoza, A. Mengoni, P. M. Milazzo, F. Mingrone, M. Mirea, S. Montesano, A. Musumarra, R. Nolte, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, I. Porras, J. Praena, J. M. Quesada, K. Rajeev, T. Rauscher, R. Reifarth, A. Riego-Perez, P. C. Rout, C. Rubbia, J. A. Ryan, M. Sabaté-Gilarte, A. Saxena, P. Schillebeeckx, S. Schmidt, D. Schumann, P. Sedyshev, A. G. Smith, A. Stamatopoulos, G. Tagliente, J. L. Tain, A. Tarifeño-Saldivia, L. Tassan-Got, A. Tsinganis, S. Valenta, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, S. Warren, M. Weigand, C. Weiss, C. Wolf, P. J. Woods, T. Wright, P. Žugec, Postprint (published version)

For purposes of engineering education, computer experiments or simulations are powerful tools to demonstrate and emphasize physical concepts instead of relying on complex and ambiguous mathematics. The main advantage of MC methods in the discipline of neutron transport that facilitates teaching is the simplicity of the Random Walk concept; thus, allowing the use of trivial arguments and visualization of problems. Simple applications of MC methods for neutron slowing-down and diffusion through elastic scattering and absorption in a homogeneous media from a monochromatic beam were illustrated separately by Peralta (2002 Eur. J. Phys. 23 307) and Capizzo et al. (2005 Eur. J. Phys. 26 85). In this contribution, the two applications are merged to serve as a course project, a few corrections to the original manuscripts are provided and important theoretical aspects are highlighted. In essence, conservation equations of neutron-nucleus collisions are solved using frame-of-reference transformation and analytical formula independently to demonstrate the equivalency using the case of slowing-down in a mixture. 1-D/3-D transformation of coordinates are reviewed and deployed to eliminate any bias in the MC simulation., Peer Reviewed, Postprint (published version)

El LINremext2 es un dosímetro de rango extendido creado por el Grupo de Física Nuclear Experimental de la UPC optimizado para protonterapia. El trabajo describe el proceso de mejora en la respuesta del prototipo, el reemplazo del sensor de neutrones térmicos y el rediseño mecánico final. Respecto al proceso de mejora, se ha analizado el modelo mediante simulaciones Monte Carlo y se han aportado propuestas que aproximan mejor su respuesta. Por otro lado, se ha estudiado el impacto por el reemplazo del sensor de neutrones térmicos por otro modelo de sensor más económico producido por la empresa europea VACUTEC, además de ser más óptimo para instalaciones de trabajos de altas energías, como es el caso de las instalaciones de protonterapia. En lo que refiere al modelo mecánico, actualmente el dosímetro de neutrones de alta energía LINremext2 es un prototipo funcional pero le falta robustez y no cumple con los estándares homologados. A través del proceso de rediseño se han establecido unas mejoras para que el prototipo sea factible de mecanizar, el sensor quede sujeto al cuerpo del dosímetro y se han añadido elementos de fijación entre la base y la tapa del modelo para que cumpla con la homologación vigente. El prototipo final es un modelo que cumple con todos los requisitos además de que dispone la función de poder operar con dos sensores de neutrones térmicos distintos en función de las instalaciones en las que se quiera operar.

he version of record os available online at: http://dx.doi.org/10.1140/epja/s10050-022-00779-7, U(n,f) cross section was measured in a wide energy range (18 meV–170 keV) at the n_TOF facility at CERN, relative to 6Li(n,t) and 10B(n,a) standard reactions, with high resolution and accuracy, with a setup based on a stack of six samples and six silicon detectors placed in the neutron beam. In this paper we report on the results in the region between 18 meV and 10 keV neutron energy. A resonance analysis has been performed up to 200 eV, with the code SAMMY. The resulting fission kernels are compared with the ones extracted on the basis of the resonance parameters of the most recent major evaluated data libraries. A comparison of the n_TOF data with the evaluated cross sections is also performed from thermal to 10 keV neutron energy for the energy-averaged cross section in energy groups of suitably chosen width. A good agreement, within 0.5%, is found on average between the new results and the latest evaluated data files ENDF/B-VIII.0 and JEFF-3.3, as well as with respect to the broad group average fission cross section established in the framework of the standard working group of IAEA (the so-called reference file). However, some discrepancies, of up to 4%, are still present in some specific energy regions. The new dataset here presented, characterized by a unique combination of high resolution and accuracy, low background and wide energy range, can help to improve the evaluations from the Resolved Resonance Region up to 10 keV, also reducing the uncertainties that affect this region., Peer Reviewed, Aquest article està escrit per 130 autors/autores: Simone Amaducci, Nicola Colonna, Luigi Cosentino, Sergio Cristallo, Paolo Finocchiaro, Milan Krtiˇcka, Cristian Massimi, Mario Mastromarco, Annamaria Mazzone, Alberto Mengoni, Stanislav Valenta, Oliver Aberle, Victor Alcayne, Józef Andrzejewski, Laurent Audouin, Victor Babiano-Suarez, Michael Bacak, Massimo Barbagallo, Samuel Bennett, Eric Berthoumieux, Jon Billowes, Damir Bosnar, Adam Brown, Maurizio Busso, Manuel Caamaño, Luis Caballero-Ontanaya, Francisco Calviño, Marco Calviani, Daniel Cano-Ott, Adria Casanovas, Francesco Cerutti, Enrico Chiaveri, Guillem Cortés, Miguel Cortés-Giraldo, Lucia-Anna Damone, Paul-John Davies, Maria Diakaki, Mirco Dietz, Cesar Domingo-Pardo, Rugard Dressler, Quentin Ducasse, Emmeric Dupont, Ignacio Durán, Zinovia Eleme, Beatriz Fernández-Domínguez, Alfredo Ferrari, Valter Furman, Kathrin Göbel, Ruchi Garg, Aleksandra Gawlik, Simone Gilardoni, Isabel Gonçalves, Enrique González-Romero, Carlos Guerrero, Frank Gunsing, Hideo Harada, Stephan Heinitz, Jan Heyse, David Jenkins, Arnd Junghans, Franz Käppeler, Yacine Kadi, Atsushi Kimura, Ingrid Knapova, Michael Kokkoris, Yuri Kopatch, Deniz Kurtulgil, Ion Ladarescu, Claudia Lederer-Woods, Helmut Leeb, Jorge Lerendegui-Marco, Sarah-Jane Lonsdale, Daniela Macina, Alice Manna, Trinitario Martínez, Alessandro Masi, Pierfrancesco Mastinu, Emilio-Andrea Maugeri, Emilio Mendoza, Veatriki Michalopoulou, Paolo Milazzo, Federica Mingrone, Javier Moreno-Soto, Agatino Musumarra, Alexandru Negret, Francisco Ogállar, Andreea Oprea, Nikolas Patronis, Andreas Pavlik, Jarosław Perkowski, Luciano Piersanti, Cristina Petrone, Elisa Pirovano, Ignacio Porras, Javier Praena, José-Manuel Quesada, Diego Ramos-Doval, Thomas Rauscher, René Reifarth, Dimitri Rochman, Carlo Rubbia, Marta Sabaté-Gilarte, Alok Saxena, Peter Schillebeeckx, Dorothea, Postprint (published version)

We report results on the long-term variation of the neutron counting rate at the Canfranc Underground Laboratory, of importance for several low-background experiments installed there, including rare-event searches. The measurement campaign was performed employing the High Efficiency Neutron Spectrometry Array (HENSA) mounted in Hall A and lasted 412 live days. The present study is the first long-term measurement of the neutron rate with sensitivity over a wide range of neutron energies (from thermal up to 0.1 GeV and beyond) performed in any underground laboratory so far. Data on the environmental variables inside the experimental hall (radon concentration, air temperature, air pressure and humidity) were also acquired during all the measurement campaign. We have investigated for the first time the evolution of the neutron rate for different energies of the neutrons and its correlation with the ambient variables., Peer Reviewed, Postprint (published version)

Nuclear level densities (NLDs) and photon strength functions (PSFs), also called ¿ -ray or radiation strength functions, represent average properties of the nucleus in the regime of excitation where individual levels and transition probabilities by ¿ decay are not readily accessible by experimental or theoretical means. They are key ingredients for statistical calculations of the reaction cross sections involving ¿ rays via the Hauser-Feshbach approach [1], like inelastic scattering or neutron capture reactions., Peer Reviewed, Aquest article té 124 autors/autores J. Moreno-Soto, S. Valenta, E. Berthoumieux, A. Chebboubi, M. Diakaki, W. Dridi, E. Dupont, F. Gunsing, M. Krticka, O. Litaize, O. Serot, O. Aberle, V. Alcayne, S. Amaducci, J. Andrzejewski, L. Audouin, V. Bécares, V. Babiano-Suarez, M. Bacak, M. Barbagallo, Th. Benedikt, S. Bennett, J. Billowes, D. Bosnar, A. Brown, M. Busso, M. Caamaño, L. Caballero-Ontanaya, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, E. Chiaveri, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, Cristallo, L. A. Damone, P. J. Davies, M. Dietz, C. Domingo-Pardo, R. Dressler, Q. Ducasse, I. Durán, Z. Eleme, B. Fernández-Domínguez, A. Ferrari, P. Finocchiaro, V. Furman, K. Göbel, A. Gawlik-Rami, S. Gilardoni, I. F. Gonçalves, E. González-RomeroC. Guerrero, S. Heinitz, J. Heyse, D. G. Jenkins, A. Junghans, F. Käppeler, Y. Kadi, A. Kimura, I. Knapová, M. Kokkoris, Y. Kopatch, D. Kurtulgil, I. Ladarescu, C. Lampoudis, C. Lederer-Woods, S. J. Lonsdale, D. Macina, A. Manna, T. Martínez, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, V. Michalopoulou, P. M. Milazzo, F. MingroneA. Musumarra, A. Negret, R. Nolte, F. Ogállar, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, L. Piersanti, C. Petrone, E. Pirovano, I. Porras, J. Praena, J. M. Quesada, D. Ramos-Doval, T. Rauscher, R. Reifarth, D. Rochman, M. Sabaté-Gilarte, A. Saxena, P. Schillebeeckx, D. Schumann, A. Sekhar, A. G. Smith, N. V. Sosnin, P. Sprung, A. Stamatopoulos, G. Tagliente, J. L. Tain, A. Tarifeño-Saldivia, L. Tassan-Got, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, G. Vannini, V. Variale, P. Vaz, A. Ventura, D. Vescovi, V. Vlachoudis, R. Vlastou, A. Wallner, P. J. Woods, T. Wright, P. Žugec, Postprint (published version)

This manuscript summarizes the results of radiative neutron capture cross-section measurements on two stable germanium isotopes, 70Ge and 73Ge. Experiments were performed at the n_TOF facility at CERN via the time-of-flight technique, over a wide neutron energy range, for all stable germanium isotopes (70,72,73,74, and 76). Results for 70Ge [Phys. Rev. C 100, 045804 (2019)] and 73Ge [Phys. Lett. B 790, 458 (2019)] are already published. In the field of nuclear structure, such measurements allow to study excited levels close to the neutron binding energy and to obtain information on nuclear properties. In stellar nucleosynthesis research, neutron induced reactions on germanium are of importance for nucleosynthesis in the weak component of the slow neutron capture processes., Peer Reviewed, Article signat per 134 autors/autores: A. Gawlik, C. Lederer-Woods, J. Andrzejewski, J. Perkowski, U. Battino, P. Ferreira, F. Gunsing, S. Heinitz, M. Krtička, C. Massimi, F. Mingrone, R. Reifarth, A. Tattersall, S. Valenta, C. Weiss, O. Aberle, L. Audouin, M. Bacak, J. Balibrea, M. Barbagallo, S. Barros, V. Bécares, F. Bečvář, C. Beinrucker, E. Berthoumieux, J. Billowes, D. Bosnar, M. Brugger, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, R. Cardella, A. Casanovas, D.M. Castelluccio, F. Cerutti, Y.H. Chen, E. Chiaveri, N. Colonna, G. Cortés, M.A. Cortés-Giraldo, L. Cosentino, L.A. Damone, M. Diakaki, M. Dietz, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, B. Fernández-Domínguez, A. Ferrari, P. Finocchiaro, V. Furman, K. Göbel, A.R. García, T. Glodariu, I.F. Gonçalves, E. González-Romero, A. Goverdovski, E. Griesmayer, C. Guerrero, H. Harada, T. Heftrich, J. Heyse, D.G. Jenkins, E. Jericha, F. Käppeler, Y. Kadi, T. Katabuchi, P. Kavrigin, V. Ketlerov, V. Khryachkov, A. Kimura, N. Kivel, I. Knapova, M. Kokkoris, E. Leal-Cidoncha, H. Leeb, J. Lerendegui-Marco, S. Lo Meo, S.J. Lonsdale, R. Losito, D. Macina, T. Martínez, P. Mastinu, M. Mastromarco, F. Matteucci, E.A. Maugeri, E. Mendoza, A. Mengoni, P.M. Milazzo, M. Mirea, S. Montesano, A. Musumarra, R. Nolte, A. Oprea, N. Patronis, A. Pavlik, J.I. Porras, J. Praena, J.M. Quesada, K. Rajeev, T. Rauscher, A. Riego-Perez, P.C. Rout, C. Rubbia, J.A. Ryan, M. Sabaté-Gilarte, A. Saxena, P. Schillebeeckx, S. Schmidt, D. Schumann, P. Sedyshev, A.G. Smith, A. Stamatopoulos, G. Tagliente, J.L. Tain, A. Tarifeño-Saldivia, L. Tassan-Got, A. Tsinganis, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, S. Warren, M. Weigand, C. Wolf, P.J. Woods, T. Wright, P. Žugec, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Postprint (author's final draft)

An accurate measurement of the 140Ce(n,¿) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the 140Ce capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in 140Ce to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the 140Ce Maxwellian-averaged cross-section., Peer Reviewed, Article signat per 130 autors/es: Simone Amaducci, Nicola Colonna, Luigi Cosentino, Sergio Cristallo, Paolo Finocchiaro, Milan Krtiˇcka, Cristian Massimi, Mario Mastromarco, Annamaria Mazzone, Alberto Mengoni, Stanislav Valenta, Oliver Aberle, Victor Alcayne, Józef Andrzejewski, Laurent Audouin, Victor Babiano-Suarez, Michael Bacak, Massimo Barbagallo, Samuel Bennett, Eric Berthoumieux, Jon Billowes, Damir Bosnar, Adam Brown, Maurizio Busso, Manuel Caamaño, Luis Caballero-Ontanaya, Francisco Calviño, Marco Calviani, Daniel Cano-Ott, Adria Casanovas, Francesco Cerutti, Enrico Chiaveri, Guillem Cortés, Miguel Cortés-Giraldo, Lucia-Anna Damone, Paul-John Davies, Maria Diakaki, Mirco Dietz, Cesar Domingo-Pardo, Rugard Dressler, Quentin Ducasse, Emmeric Dupont, Ignacio Durán, Zinovia Eleme, Beatriz Fernández-Domínguez, Alfredo Ferrari, Valter Furman, Kathrin Göbel, Ruchi Garg, Aleksandra Gawlik, Simone Gilardoni, Isabel Gonçalves, Enrique González-Romero, Carlos Guerrero, Frank Gunsing, Hideo Harada, Stephan Heinitz, Jan Heyse, David Jenkins, Arnd Junghans, Franz Käppeler, Yacine Kadi, Atsushi Kimura, Ingrid Knapova, Michael Kokkoris, Yuri Kopatch, Deniz Kurtulgil, Ion Ladarescu, Claudia Lederer-Woods, Helmut Leeb, Jorge Lerendegui-Marco, Sarah-Jane Lonsdale, Daniela Macina, Alice Manna, Trinitario Martínez, Alessandro Masi, Pierfrancesco Mastinu, Emilio-Andrea Maugeri, Emilio Mendoza, Veatriki Michalopoulou, Paolo Milazzo, Federica Mingrone, Javier Moreno-Soto, Agatino Musumarra, Alexandru Negret, Francisco Ogállar, Andreea Oprea, Nikolas Patronis, Andreas Pavlik, Jarosław Perkowski, Luciano Piersanti, Cristina Petrone, Elisa Pirovano, Ignacio Porras, Javier Praena, José-Manuel Quesada, Diego Ramos-Doval, Thomas Rauscher, René Reifarth, Dimitri Rochman, Carlo Rubbia, Marta Sabaté-Gilarte, Alok Saxena, Peter Schillebeeckx, Dorothea Schumann, Adhitya Sekhar, Gavin Smith, Nikolay Sosnin, Peter Sprung, Athanasios Stamatopoulos, Giuseppe Tagliente, José Tain, Ariel Tarifeño, Postprint (author's final draft)

Theoretical models of ß-delayed neutron emission are used as crucial inputs in r-process calculations. Benchmarking the predictions of these models is a challenge due to a lack of currently available experimental data. In this work the ß-delayed neutron emission probabilities of 33 nuclides in the important mass regions south and south-west of 132Sn are presented, 16 for the first time. The measurements were performed at RIKEN using the Advanced Implantation Detector Array (AIDA) and the BRIKEN neutron detector array. The values presented constrain the predictions of theoretical models in the region, affecting the final abundance distribution of the second r-process peak at ., Peer Reviewed, Article signat per 58 autors/es J. Liu, S. Bae, N.T. Brewer, C.G. Bruno, R. Caballero-Folch, P.J. Coleman-Smith, I. Dillmann, C. Domingo-Pardo, A. Fijalkowska, N. Fukuda, S. Go, C.J. Griffin, R. Grzywacz, J. Ha, L. J. Harkness-Brennan, T. Isobe, D. Kahl, L.H. Khiem, G.G. Kiss, A. Korgul, S. Kubono, M. Labiche, I. Lazarus, P. Morrall, M.R. Mumpower, N. Nepal, R.D. Page, M. Piersa , V.F.E. Pucknell , B.C. Rasco, B. Rubio, K.P. Rykaczewski , H. Sakurai , Y. Shimizu , D.W. Stracener, T. Sumikama , H. Suzuki, J.L. Tain , H. Takeda, A. Tarifeño-Saldivia, A. Tolosa-Delgado , M. Wolinska-Cichocka , R. Yokoyama, Postprint (author's final draft)

The 76 Ge ( n , ¿ ) reaction has been measured at the n_TOF facility at CERN via the time-of-flight technique. Neutron capture cross sections on 76 Ge are of interest to a variety of low-background experiments, such as neutrinoless double ß decay searches, and to nuclear astrophysics. We have determined resonance capture kernels up to 52 keV neutron energy and used the new data to calculate Maxwellian-averaged neutron capture cross sections for k B T values of 5 to 100 keV., Peer Reviewed, Article signat per 134 autors/es: A. Gawlik, C. Lederer-Woods, J. Andrzejewski, J. Perkowski, U. Battino, P. Ferreira, F. Gunsing, S. Heinitz, M. Krtička, C. Massimi, F. Mingrone, R. Reifarth, A. Tattersall, S. Valenta, C. Weiss, O. Aberle, L. Audouin, M. Bacak, J. Balibrea, M. Barbagallo, S. Barros, V. Bécares, F. Bečvář, C. Beinrucker, E. Berthoumieux, J. Billowes, D. Bosnar, M. Brugger, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, R. Cardella, A. Casanovas, D.M. Castelluccio, F. Cerutti, Y.H. Chen, E. Chiaveri, N. Colonna, G. Cortés, M.A. Cortés-Giraldo, L. Cosentino, L.A. Damone, M. Diakaki, M. Dietz, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, B. Fernández-Domínguez, A. Ferrari, P. Finocchiaro, V. Furman, K. Göbel, A.R. García, T. Glodariu, I.F. Gonçalves, E. González-Romero, A. Goverdovski, E. Griesmayer, C. Guerrero, H. Harada, T. Heftrich, J. Heyse, D.G. Jenkins, E. Jericha, F. Käppeler, Y. Kadi, T. Katabuchi, P. Kavrigin, V. Ketlerov, V. Khryachkov, A. Kimura, N. Kivel, I. Knapova, M. Kokkoris, E. Leal-Cidoncha, H. Leeb, J. Lerendegui-Marco, S. Lo Meo, S.J. Lonsdale, R. Losito, D. Macina, T. Martínez, P. Mastinu, M. Mastromarco, F. Matteucci, E.A. Maugeri, E. Mendoza, A. Mengoni, P.M. Milazzo, M. Mirea, S. Montesano, A. Musumarra, R. Nolte, A. Oprea, N. Patronis, A. Pavlik, J.I. Porras, J. Praena, J.M. Quesada, K. Rajeev, T. Rauscher, A. Riego-Perez, P.C. Rout, C. Rubbia, J.A. Ryan, M. Sabaté-Gilarte, A. Saxena, P. Schillebeeckx, S. Schmidt, D. Schumann, P. Sedyshev, A.G. Smith, A. Stamatopoulos, G. Tagliente, J.L. Tain, A. Tarifeño-Saldivia, L. Tassan-Got, A. Tsinganis, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, S. Warren, M. Weigand, C. Wolf, P.J. Woods, T. Wright, P. Žugec, Postprint (author's final draft)

We have performed a long-term measurement of the neutron flux with the High Efficiency Neutron Spectrometry Array HENSA in the Hall A of the Canfranc Underground Laboratory. The Hall A measurement campaign lasted from October 2019 to March 2021, demonstrating an excellent stability of the HENSA setup. Preliminary results on the neutron flux from this campaign are presented for the first time. In Phase 1 (113 live days) a total neutron flux of 1.662 ¿10–5 cm–2 s–1 is obtained. Our results are in good agreement with those from our previous shorter measurement where a reduced experimental setup was employed., This work was supported by the Spanish MICINN Grants No. PID2019-104714GB-C21 and No. FPA2017- 83946-C2-1-P (MCIU/AEI/FEDER). We acknowledge the support of the Generalitat Valenciana Grant No. PROMETEO/2019/007. We are grateful to Laboratorio Subterráneo de Canfranc for hosting the HENSA spectrometer and for the support received by the LSC personnel during the measurement campaign., Peer Reviewed, Postprint (published version)

The HENSA/ANAIS collaboration aims for the precise determination of the neutron flux that could affect ANAIS-112, an experiment looking for the dark matter annual modulation using NaI(Tl) scintillators. In this work, the first measurements of the neutron flux and Monte Carlo simulations of the neutron spectrum are reported., Peer Reviewed, Postprint (published version)

The 26 Al ( n , p ) 26 Mg reaction is the key reaction impacting on the abundances of the cosmic ¿ -ray emitter 26 Al produced in massive stars and impacts on the potential pollution of the early solar system with 26 Al by asymptotic giant branch stars. We performed a measurement of the 26 Al ( n , p ) 26 Mg cross section at the high-flux beam line EAR-2 at the n_TOF facility (CERN). We report resonance strengths for eleven resonances, nine being measured for the first time, while there is only one previous measurement for the other two. Our resonance strengths are significantly lower than the only previous values available. Our cross-section data range to 150 keV neutron energy, which is sufficient for a reliable determination of astrophysical reactivities up to 0.5 GK stellar temperature., Peer Reviewed, Postprint (published version)

The 72 Ge ( n , ¿ ) cross section was measured for neutron energies up to 300 keV at the neutron time-of-flight facility n _ TOF (CERN), Geneva, for the first time covering energies relevant to heavy-element synthesis in stars. The measurement was performed at the high-resolution beamline EAR-1, using an isotopically enriched 72 Ge O 2 sample. The prompt capture ¿ rays were detected with four liquid scintillation detectors, optimized for low neutron sensitivity. We determined resonance capture kernels up to a neutron energy of 43 keV , and averaged cross sections from 43 to 300 keV . Maxwellian-averaged cross section values were calculated from k T = 5 to 100 keV , with uncertainties between 3.2 % and 7.1 % . The new results significantly reduce uncertainties of abundances produced in the slow neutron capture process in massive stars., Peer Reviewed, Article signat per 144 autors/es: M. Dietz ,C. Lederer-Woods, A. Tattersall, U. Battino, F. Gunsing, S. Heinitz, M. Krticka, J. Lerendegui-Marco, R. Reifarth, S. Valenta, O. Aberle, S. Amaducci, J. Andrzejewski, L. Audouin, M. Bacak, J. Balibrea, M. Barbagallo, F. Becvá, E. Berthoumieux, J. Billowes, D. Bosnar, A. Brown, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, R. Cardella, A. Casanovas, F. Cerutti, Y. H. Chen, E. Chiaveri, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, L. A. Damone, M. Diakaki,C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, B. Fernández-Domínguez, A. Ferrari, P. Ferreira, P. Finocchiaro, V. Furman,K. Göbel, A. R. García, A. Gawlik, S. Gilardoni, T. Glodariu, I. F. Gonçalves, E. González-Romero, E. Griesmayer, C. Guerrero, H. Harada, J. Heyse, D. G. Jenkins, E. Jericha, F. Käppeler, Y. Kadi, D. Kahl, A. Kalamara, P. Kavrigin, A. Kimura, N. Kivel, M. Kokkoris, D. Kurtulgil, E. Leal-Cidoncha, H. Leeb, S. Lo Meo, S. J. Lonsdale, D. Macina, A. Manna, J. Marganiec, T. Martínez, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, P. M. Milazzo, F. Mingrone, A. Musumarra, A. Negret, R. Nolte, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, I. Porras, J. Praena, J. M. Quesada, D. Radeck, T. Rauscher, C. Rubbia, J. A. Ryan, M. Sabaté-Gilarte, A. Saxena, P. Schillebeeckx, D. Schumann, P. Sedyshev, A. G. Smith, N. V. Sosnin, A. Stamatopoulos, G. Tagliente, J. L. Tain, A. Tarifeño-Saldivia, L. Tassan-Got, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, S. Warren, C. Weiss, P. J. Woods, T. Wright, P. Žugec, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Postprint (author's final draft)

Low efficiency total-energy detectors (TEDs) are one of the main tools for neutron capture cross section measurements utilizing the time-of-flight (TOF) technique. State-of-the-art TEDs are based on a CD liquid-scintillation cell optically coupled to a fast photomultiplier tube. The large photomultiplier tube represents yet a significant contribution to the so-called neutron sensitivity background, which is one of the most conspicuous sources of uncertainty in this type of experiments. Here we report on the development of a first prototype of a TED based on a silicon-photomultiplier (SiPM) readout, thus resulting in a lightweight and much more compact detector. Apart from the envisaged improvement in neutron sensitivity, the new system uses low voltage (+28 V) and low current supply (50 mA), which is more practical than the kV supply required by conventional photomultipliers. One important difficulty hindering the earlier implementation of SiPM readout for this type of detector was the large capacitance for the output signal when all pixels of a SiPM array are summed together. The latter leads to long pulse rise and decay times, which are not suitable for time-of-flight experiments. In this work we demonstrate the feasibility of a Schottky-diode multiplexing readout approach, that allows one to preserve the excellent timing properties of SiPMs, hereby paving the way for their implementation in future neutron TOF experiments., Postprint (published version)

Background: Nuclear waste management is considered amongst the major challenges in the field of nuclear energy. A possible means of addressing this issue is waste transmutation in advanced nuclear systems, whose operation requires a fast neutron spectrum. In this regard, the accurate knowledge of neutron-induced reaction cross sections of several (minor) actinide isotopes is essential for design optimization and improvement of safety margins of such systems. One such case is 240 Pu , due to its accumulation in spent nuclear fuel of thermal reactors and its usage in fast reactor fuel. The measurement of the 240 Pu ( n , f ) cross section was previously attempted at the CERN n_TOF facility EAR1 measuring station using the time-of-flight technique. Due to the low amount of available material and the given flux at EAR1, the measurement had to last several months to achieve a sufficient statistical accuracy. This long duration led to detector deterioration due to the prolonged exposure to the high a activity of the fission foils, therefore the measurement could not be successfully completed. Purpose: It is aimed to determine whether it is feasible to study neutron-induced fission at n_TOF/EAR2 and provide data on the 240 Pu ( n , f ) reaction in energy regions requested for applications. Methods: The study of the 240 Pu ( n , f ) reaction was made at a new experimental area (EAR2) with a shorter flight path which delivered on average 30 times higher flux at fast neutron energies. This enabled the measurement to be performed much faster, thus limiting the exposure of the detectors to the intrinsic activity of the fission foils. The experimental setup was based on microbulk Micromegas detectors and the time-of-flight data were analyzed with an optimized pulse-shape analysis algorithm. Special attention was dedicated to the estimation of the non-negligible counting loss corrections with the development of a new methodology, and other corrections were estimated via Monte Car, Postprint (published version)

We measured the neutron capture-to-fission cross-section ratio (a ratio) and the capture cross section of 235U between 0.2 and 200 eV at the n_TOF facility at CERN. The simultaneous measurement of neutron-induced capture and fission rates was performed by means of the n_TOF BaF2 Total Absorption Calorimeter (TAC), used for detection of ¿ rays, in combination with a set of micromegas detectors used as fission tagging detectors. The energy dependence of the capture cross section was obtained with help of the 6 Li(n,t) standard reaction determining the n_TOF neutron fluence; the well-known integral of the 235U(n, f ) cross section between 7.8 and 11 eV was then used for its absolute normalization. The a ratio, obtained with slightly higher statistical fluctuations, was determined directly, without need for any reference cross section. To perform the analysis of this measurement we developed a new methodology to correct the experimentally observed effect that the probabilities of detecting a fission reaction in the TAC and the micromegas detectors are not independent. The results of this work have been used in a new evaluation of 235U performed within the scope of the Collaborative International Evaluated Library Organisation (CIELO) Project, and are consistent with the ENDF/B-VIII.0 and JEFF-3.3 capture cross sections below 4 eV and above 100 eV. However, the measured capture cross section is on average 10% larger between 4 and 100 eV, Postprint (published version)

In the measurement of neutron capture cross-sections of fissile isotopes, the fission channel is a source of background which can be removed efficiently using the so-called fission-tagging or fission-veto technique. For this purpose a new compact and fast fission chamber has been developed. The design criteria and technical description of the chamber are given within the context of a measurement of the 233U(n,gamma) cross-section at the n_TOF facility at CERN, where it was coupled to the n_TOF Total Absorption Calorimeter. For this measurement the fission detector was optimized for time resolution, minimization of material in the neutron beam and for alpha-fission discrimination. The performance of the fission chamber and its application as a fission tagging detector are discussed., Postprint (published version)

The neutron capture cross section of 154Gd was measured from 1 eV to 300 keV in the experimental area located 185 m from the CERN n_TOF neutron spallation source, using a metallic sample of gadolinium, enriched to 67% in 154Gd. The capture measurement, performed with four C6D6 scintillation detectors, has been complemented by a transmission measurement performed at the GELINA time-of-flight facility (JRC-Geel), thus minimising the uncertainty related to sample composition. An accurate Maxwellian averaged capture cross section (MACS) was deduced over the temperature range of interest for s process nucleosynthesis modelling. We report a value of 880(50) mb for the MACS at keV, significantly lower compared to values available in literature. The new adopted 154Gd(n,¿) cross section reduces the discrepancy between observed and calculated solar s-only isotopic abundances predicted by s-process nucleosynthesis models., Postprint (published version)

Although the 12C(n,p)12B and 12C(n,d)11B reactions are of interest in several fields of basic and applied Nuclear Physics the present knowledge of these two cross-sections is far from being accurate and reliable, with both evaluations and data showing sizable discrepancies. As part of the challenging n_TOF program on (n,cp) nuclear reactions study, the energy differential cross-sections of the 12C(n,p)12B and 12C(n,d)11 B reactions have been measured at CERN from the reaction thresholds up to 30 MeV neutron energy. Both measurements have been recently performed at the long flight-path (185 m) experimental area of the n_TOF facility at CERN using a pure (99.95%) rigid graphite target and two silicon telescopes. In this paper an overview of the experiment is presented together with a few preliminary results.

Accurate neutron capture cross section data for minor actinides (MAs) are required to estimate the production and transmutation rates of MAs in light water reactors with a high burnup, critical fast reactors like Gen-IV systems and other innovative reactor systems such as accelerator driven systems (ADS). Capture reactions of 244Cm open the path for the formation of heavier Cm isotopes and of heavier elements such as Bk and Cf. In addition, 244Cm shares nearly 50% of the total actinide decay heat in irradiated reactor fuels with a high burnup, even after three years of cooling. Experimental data for this isotope are very scarce due to the difficulties of providing isotopically enriched samples and because the high intrinsic activity of the samples requires the use of neutron facilities with high instantaneous flux. The only two previous experimental data sets for this neutron capture cross section have been obtained in 1969 using a nuclear explosion and, more recently, at J-PARC in 2010. The neutron capture cross sections have been measured at n_TOF with the same samples that the previous experiments in J-PARC. The samples were measured at n_TOF Experimental Area 2 (EAR-2) with three C6D6 detectors and also in Experimental Area 1 (EAR-1) with the Total Absorption Calorimeter (TAC). Preliminary results assessing the quality and limitations of these new experimental datasets are presented for the experiments in both areas. Preliminary yields of both measurements will be compared with evaluated libraries for the first time.

The neutron induced fission of 235U is extensively used as a reference for neutron fluence measurements in various applications, ranging from the investigation of the biological effectiveness of high energy neutrons, to the measurement of high energy neutron cross sections of relevance for accelerator driven nuclear systems. Despite its widespread use, no data exist on neutron induced fission of 235U above 200 MeV. The neutron facility n_TOF offers the possibility to improve the situation. The measurement of 235U(n,f) relative to the differential n-p scattering cross-section, was carried out in September 2018 with the aim of providing accurate and precise cross section data in the energy range from 10 MeV up to 1 GeV. In such measurements, Recoil Proton Telescopes (RPTs) are used to measure the neutron flux while the fission events are detected and counted with dedicated detectors. In this paper the measurement campaign and the experimental set-up are illustrated.

Neutron-induced fission cross sections of isotopes involved in the nuclear fuel cycle are vital for the design and safe operation of advanced nuclear systems. Such experimental data can also provide additional constraints for the adjustment of nuclear model parameters used in the evaluation process, resulting in the further development of fission models. In the present work, the 237Np(n,f) cross section was studied at the EAR2 vertical beam-line at CERN's n_TOF facility, over a wide range of neutron energies, from meV to MeV, using the time-of-flight technique and a set-up based on Micromegas detectors, in an attempt to provide accurate experimental data. Preliminary results in the 200 keV – 14 MeV neutron energy range as well as the experimental procedure, including a description of the facility and the data handling and analysis, will be presented.

Since the start of its operation in 2001, based on an idea of Prof. Carlo Rubbia [1], the neutron time of-flight facility of CERN, n_TOF, has become one of the most forefront neutron facilities in the world for wide-energy spectrum neutron cross section measurements. Thanks to the combination of excellent neutron energy resolution and high instantaneous neutron flux available in the two experimental areas, the second of which has been constructed in 2014, n_TOF is providing a wealth of new data on neutron-induced reactions of interest for nuclear astrophysics, advanced nuclear technologies and medical applications. The unique features of the facility will continue to be exploited in the future, to perform challenging new measurements addressing the still open issues and long-standing quests in the field of neutron physics. In this document the main characteristics of the n_TOF facility and their relevance for neutron studies in the different areas of research will be outlined, addressing the possible future contribution of n_TOF in the fields of nuclear astrophysics, nuclear technologies and medical applications. In addition, the future perspectives of the facility will be described including the upgrade of the spallation target, the setup of an imaging installation and the construction of a new irradiation area.

Neutron capture cross sections are fundamental in the study of the slow neutron capture process of nucleosynthesis, also known as the s-process, which produces half of the observed solar system abundances of elements heavier than iron. Some nuclei along the nucleosynthesis chain are unstable, and there the capture process competes with the decay process, creating a split in the nucleosynthesis path. The nuclear properties of some of these radionuclides change with the conditions of the stellar environment, a fact that influences the local abundance pattern. 204Tl is a very interesting branching point, because it is shielded from any contribution from other nucleosynthesis processes. The result is that both 204Tl and its stable daughter isotope 204Pb are only produced by the s-process. Hence, by competing with the beta decay, the capture cross section of 204Tl crucially determines the final abundance of 204Pb. A faithful prediction of the solar abundances of s-only isotopes, like 204Pb, is one of the key accuracy tests for modern stellar nucleosynthesis calculations. However, until the present work, due to the challenges of performing a capture measurement on 204Tl, there was no experimental data of its cross section. Thus, large uncertainties existed in its capture cross section, which hampered a more accurate and precise knowledge of the predicted s-process production of 204Pb. By affecting the abundance of 204Pb, the cross section of 204Tl(n,¿) also influences the ratio of abundances 205Pb/204Pb. 205Pb is also produced only by the s-process, and it is radioactive, with a long half-life of 17.2 My. Therefore, the ratio of abundances of 205Pb/204Pb has the potential to be used as a chronometer of the s-process. In the year 2013, a sample enriched up to a few percent in 204Tl was produced by neutron irradiation of a 203Tl seed sample at the high thermal neutron flux nuclear reactor of the ILL, in Grenoble (France). Two years later, the 204Tl enriched sample was emplo, Les seccions eficaces de captura de neutrons són fonamentals en l'estudi del procés lent de nucleosíntesi estel·lar dels elements, també conegut com a procés s (de l'anglès "slow"). El procés s és responsable de la producció d'aproximadament la meitat de les abundàncies solars dels elements més pesats que el ferro. Alguns nuclis en la cadena de nucleosíntesi són inestables, i en aquests el procés de captura competeix amb el procés de desintegració, el que dóna lloc a una ramificació del camí de producció dels elements. Les propietats nuclears d'alguns d'aquests núclids canvien amb les condicions de l'entorn estel·lar on són produïts, el que influencia el patró d'abundàncies local. El 204Tl és un punt de ramificació molt interessant, perquè està protegit de contribucions d'altres processos de nucleosíntesi. El resultat és que tant el 204Tl com el seu producte de desintegració 204Pb només són produïts pel procés s. Per tant, degut que competeix amb el procés de desintegració, la secció eficaç de captura neutrònica del 204Tl és clau per fixar l'abundància final de 204Pb. Una predicció cartera de l'abundància dels núclids només produïts pel procés s és una de les proves de precisió dels models de càlculs de nucleosíntesi estel·lar. Tot i això, fins el present treball, no hi havia dades de la seva secció eficaç degut al reptes en la realització d'una mesura de captura en el 204Tl. Això feia que hi hagués una incertesa important en la secció eficaç estel·lar, la qual cosa dificultava una predicció precisa de la producció de 204Pb pel procés s. De la mateixa manera, la secció eficaç de 204Tl(n,y) també afecta la relació d'abundàncies 205Pb/204Pb. Degut al fet que el 205Pb és radioactiu, amb un període de semidesintegració de 17,2 Ma, la dita relació té el potencial de ser usada com a cronòmetre del procés s. L'any 2013, es va produir una mostra enriquida en 204Tl per irradiació neutrònica d'una llavor de 203Tl al reactor nuclear del ILL de Grenoble (França). Dos anys despr, Postprint (published version)