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1. Status report of the n_TOF facility after the 2nd CERN long shutdown period

Author

N. Patronis, A. Mengoni, S. Goula, O. Aberle, V. Alcayne, S. Altieri, S. Amaducci, J. Andrzejewski, V. Babiano-Suarez, M. Bacak, J. Balibrea Correa, C. Beltrami, S. Bennett, A. P. Bernardes, E. Berthoumieux, R. Beyer, M. Boromiza, D. Bosnar, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, 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, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, Z. Eleme, S. Fargier, B. Fernández, B. Fernández-Domínguez, P. Finocchiaro, S. Fiore, F. García-Infantes, A. Gawlik-Ramiega, 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, G. Kaur, A. Kimura, I. Knapová, M. Kokkoris, M. Krtička, N. Kyritsis, I. Ladarescu, C. Lederer-Woods, J. Lerendegui-Marco, G. Lerner, A. Manna, T. Martínez, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, V. Michalopoulou, P. M. Milazzo, R. Mucciola, F. Murtas, E. Musacchio-Gonzalez, A. Musumarra, A. Negret, A. Pérez de Rada, P. Pérez-Maroto, J. A. Pavón-Rodríguez, M. G. Pellegriti, J. Perkowski, C. Petrone, E. Pirovano, J. Plaza del Olmo, S. Pomp, I. Porras, J. Praena, J. M. Quesada, R. Reifarth, D. Rochman, Y. Romanets, C. Rubbia, A. Sánchez-Caballero, M. Sabaté-Gilarte, P. Schillebeeckx, D. Schumann, A. Sekhar, A. G. Smith, N. V. Sosnin, 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, R. Zarrella, and P. Zugec

Subjects
Neutron time of flight, Spallation target, Nuclear astrophysics, Neutron physics, Neutron induced fission, Neutron reactions, Physics, QC1-999, Optics. Light, QC350-467, Descriptive and experimental mechanics, QC120-168.85
Abstract

Abstract During the second long shutdown period of the CERN accelerator complex (LS2, 2019-2021), several upgrade activities took place at the n_TOF facility. The most important have been the replacement of the spallation target with a next generation nitrogen-cooled lead target. Additionally, a new experimental area, at a very short distance from the target assembly (the NEAR Station) was established. In this paper, the core commissioning actions of the new installations are described. The improvement in the n_TOF infrastructure was accompanied by several detector development projects. All these upgrade actions are discussed, focusing mostly on the future perspectives of the n_TOF facility. Furthermore, some indicative current and future measurements are briefly reported.

Published
2023
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2. Low Mass Stars or Intermediate Mass Stars? The Stellar Origin of Presolar Oxide Grains Revealed by Their Isotopic Composition

Author

S. Palmerini, S. Cristallo, M. Busso, M. La Cognata, M. L. Sergi, and D. Vescovi

Subjects
AGB stars, presolar grains, nucleosynthesis–stars: abundances, reaction rates, isotopic abundances, Astronomy, QB1-991, Geophysics. Cosmic physics, QC801-809
Abstract

Among presolar grains, oxide ones are made of oxygen, aluminum, and a small fraction of magnesium, produced by the 26Al decay. The largest part of presolar oxide grains belong to the so-called group 1 and 2, which have been suggested to form in Red Giant Branch (RGB) and Asymptotic Giant Branch (AGB) stars, respectively. However, standard stellar nucleosynthesis models cannot account for the 17O/16O, 18O/16O, and 26Al/27Al values recorded in those grains. Hence, for more than 20 years, the occurrence of mixing phenomena coupled with stellar nucleosynthesis have been suggested to account for this peculiar isotopic mix. Nowadays, models of massive AGB stars experiencing Hot Bottom Burning or low mass AGB stars where Cool Bottom Process, or another kind of extra-mixing, is at play, nicely fit the oxygen isotopic mix of group 2 oxide grains. The largest values of the 26Al/27Al ratio seem somewhat more difficult to account for.

Published
2021
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3. Measurement of the 154Gd(n,γ) cross section and its astrophysical implications

Author

A. Mazzone, S. Cristallo, O. Aberle, G. Alaerts, V. Alcayne, S. Amaducci, J. Andrzejewski, L. Audouin, V. Babiano-Suarez, M. Bacak, M. Barbagallo, V. Bécares, F. Bečvář, 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, D.M. Castelluccio, F. Cerutti, Y.H. Chen, E. Chiaveri, G. Clai, N. Colonna, G.P. Cortés, M.A. Cortés-Giraldo, L. Cosentino, L.A. Damone, 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. Göbel, E. González-Romero, C. Guerrero, F. Gunsing, S. Heinitz, J. Heyse, D.G. Jenkins, E. Jericha, Y. Kadi, F. Käppeler, A. Kimura, N. Kivel, M. Kokkoris, Y. Kopatch, S. Kopecky, M. Krtička, D. Kurtulgil, I. Ladarescu, C. Lederer-Woods, J. Lerendegui-Marco, S. Lo Meo, S.-J. Lonsdale, D. Macina, A. Manna, T. Martínez, A. Masi, C. Massimi, P.F. Mastinu, M. Mastromarco, F. Matteucci, E. Maugeri, E. Mendoza, A. Mengoni, V. Michalopoulou, P.M. Milazzo, F. Mingrone, R. Mucciola, 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, P. Schillebeeckx, D. Schumann, A.G. Smith, N. Sosnin, A. Stamatopoulos, G. Tagliente, J.L. Tain, Z. Talip, A.E. Tarifeño-Saldivia, L. Tassan-Got, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, S. Valenta, G. Vannini, V. Variale, P. Vaz, A. Ventura, D. Vescovi, V. Vlachoudis, R. Vlastou, A. Wallner, P.J. Woods, R. Wynants, T.J. Wright, and P. Žugec

Subjects
Physics, QC1-999
Abstract

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 kT=30 keV, significantly lower compared to values available in literature. The new adopted 154Gd(n,γ) cross section reduces the discrepancy between observed and calculated solar s-only isotopic abundances predicted by s-process nucleosynthesis models. Keywords: s process, 154Gd, Neutron time of flight, n_TOF

Published
2020
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4. Neutron spectroscopy of 26Mg states: Constraining the stellar neutron source 22Ne(α,n)25Mg

Author

C. Massimi, S. Altstadt, J. Andrzejewski, L. Audouin, M. Barbagallo, V. Bécares, F. Bečvář, F. Belloni, E. Berthoumieux, J. Billowes, S. Bisterzo, D. Bosnar, M. Brugger, M. Calviani, F. Calviño, D. Cano-Ott, C. Carrapiço, D.M. Castelluccio, F. Cerutti, E. Chiaveri, L. Cosentino, M. Chin, G. Clai, N. Colonna, G. Cortés, M.A. Cortés-Giraldo, S. Cristallo, M. Diakaki, C. Domingo-Pardo, I. Duran, R. Dressler, C. Eleftheriadis, A. Ferrari, P. Finocchiaro, K. Fraval, S. Ganesan, A.R. García, G. Giubrone, I.F. Gonçalves, E. González-Romero, E. Griesmayer, C. Guerrero, F. Gunsing, A. Hernández-Prieto, D.G. Jenkins, E. Jericha, Y. Kadi, F. Käppeler, D. Karadimos, N. Kivel, P. Koehler, M. Kokkoris, S. Kopecky, M. Krtička, J. Kroll, C. Lampoudis, C. Langer, E. Leal-Cidoncha, C. Lederer, H. Leeb, L.S. Leong, S. Lo Meo, R. Losito, A. Mallick, A. Manousos, J. Marganiec, T. Martínez, P.F. Mastinu, M. Mastromarco, E. Mendoza, A. Mengoni, P.M. Milazzo, F. Mingrone, M. Mirea, W. Mondelaers, A. Musumarra, C. Paradela, A. Pavlik, J. Perkowski, M. Pignatari, L. Piersanti, A. Plompen, J. Praena, J.M. Quesada, T. Rauscher, R. Reifarth, A. Riego, M.S. Robles, C. Rubbia, M. Sabaté-Gilarte, R. Sarmento, A. Saxena, P. Schillebeeckx, S. Schmidt, D. Schumann, G. Tagliente, J.L. Tain, D. Tarrío, L. Tassan-Got, A. Tsinganis, S. Valenta, G. Vannini, I. Van Rijs, V. Variale, P. Vaz, A. Ventura, M.J. Vermeulen, V. Vlachoudis, R. Vlastou, A. Wallner, T. Ware, M. Weigand, C. Weiß, R. Wynants, T. Wright, and P. Žugec

Subjects
s Process, α+22Ne, Neutron spectroscopy, Physics, QC1-999
Abstract

This work reports on accurate, high-resolution measurements of the 25Mg(n,γ)26Mg and 25Mg(n,tot) cross sections in the neutron energy range from thermal to about 300 keV, leading to a significantly improved 25Mg(n,γ)26Mg parametrization. The relevant resonances for n+25Mg were characterized from a combined R-matrix analysis of the experimental data. This resulted in an unambiguous spin/parity assignment of the corresponding excited states in 26Mg. With this information experimental upper limits of the reaction rates for 22Ne(α,n)25Mg and 22Ne(α,γ)26Mg were established, potentially leading to a significantly higher (α,n)/(α,γ) ratio than previously evaluated. The impact of these results has been studied for stellar models in the mass range 2 to 25 M⊙.

Published
2017
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5. Magnetic-buoyancy-induced mixing in AGB Stars: a theoretical explanation of the non-universal [Y/Mg]-age relation

Author

L., Magrini, D., Vescovi, G., Casali, S., Cristallo, C., Viscasillas Vazquez, G., Cescutti, L., Spina, M., Van Der Swaelmen, and S, Randich

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract

The use of abundance ratios involving Y, or other slow-neutron capture elements, are routinely used to infer stellar ages.Aims.We aim to explain the observed [Y/H] and [Y/Mg] abundance ratios of star clusters located in the inner disc with a new prescription for mixing in Asymptotic Giant Branch (AGB) stars. In a Galactic chemical evolution model, we adopt a new set of AGB stellar yields in which magnetic mixing is included. We compare the results of the model with a sample of abundances and ages of open clusters located at different Galactocentric distances. The magnetic mixing causes a less efficient production of Y at high metallicity. A non-negligible fraction of stars with super-solar metallicity is produced in the inner disc, and their Y abundances are affected by the reduced yields. The results of the new AGB model qualitatively reproduce the observed trends for both [Y/H] and [Y/Mg] vs age at different Galactocetric distances. Our results confirm from a theoretical point of view that the relationship between [Y/Mg] and stellar age cannot be universal, i.e., the same in every part of the Galaxy. It has a strong dependence on the star formation rate, on the s-process yields and their relation with metallicity, and thus it varies across the Galactic disc., Comment: Accepted for publication as an A&A Letter

Published
2021
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6. The Gaia-ESO survey: placing constraints on the origin of r-process elements

Author

M. Van der Swaelmen, C. Viscasillas Vázquez, G. Cescutti, L. Magrini, S. Cristallo, D. Vescovi, S. Randich, G. Tautvaišienė, V. Bagdonas, T. Bensby, M. Bergemann, A. Bragaglia, A. Drazdauskas, F. Jiménez-Esteban, G. Guiglion, A. Korn, T. Masseron, R. Minkeviiūtė, R. Smiljanic, L. Spina, E. Stonkutė, S. Zaggia, Van der Swaelmen, M., Viscasillas Vázquez, C., Cescutti, G., Magrini, L., Cristallo, S., Vescovi, D., Randich, S., Tautvaišienė, G., Bagdonas, V., Bensby, T., Bergemann, M., Bragaglia, A., Drazdauskas, A., Jiménez-Esteban, F., Guiglion, G., Korn, A., Masseron, T., Minkevičiūtė, R., Smiljanic, R., Spina, L., Stonkutė, E., and Zaggia, S.

Subjects
CLUSTERS TRUMPLER 20, FOS: Physical sciences, NEUTRON-STAR MERGERS, Astrophysics, Astrophysics of Galaxies, Astrophysics Solar and Stellar Astrophysics, HEAVY-ELEMENTS, STELLAR POPULATIONS, Astrophysic, PROCESS NUCLEOSYNTHESIS, Astronomi, astrofysik och kosmologi, Astronomy, Astrophysics and Cosmology, STOCHASTIC CHEMICAL EVOLUTION, Astrophysics of Galaxie, GIANT BRANCH STARS, Solar and Stellar Astrophysics (astro-ph.SR), abundances [Galaxy], Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, abundances [stars], ALPHA-RICH STARS, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), MILKY-WAY, CAPTURE ELEMENTS, general [open clusters and associations], disk [Galaxy]
Abstract

A renewed interest about the origin of \emph{r}-process elements has been stimulated by the multi-messenger observation of the gravitational event GW170817, with the detection of both gravitational waves and electromagnetic waves corresponding to the merger of two neutron stars. Such phenomenon has been proposed as one of the main sources of the \emph{r}-process. However, the origin of the \emph{r}-process elements at different metallicities is still under debate. We aim at investigating the origin of the \emph{r}-process elements in the Galactic thin disc population. From the sixth internal data release of the \emph{Gaia}-ESO we have collected a large sample of Milky Way thin- and thick-disc stars for which abundances of Eu, O, and Mg are available. The sample consists of members of 62 open clusters, located at a Galactocentric radius from $\sim 5$ kpc to $\sim 20$ kpc in the disc, in the metallicity range $[-0.5, 0.4]$ and covering an age interval from 0.1 to 7 Gy, and about 1300 Milky Way disc field stars in the metallicity range $[-1.5, 0.5]$. We compare the observations with the results of a chemical evolution model, in which we varied the nucleosynthesis sources for the three considered elements. Our main result is that Eu in the thin disc is predominantly produced by sources with short lifetimes, such as magneto-rotationally driven SNe. There is no strong evidence for additional sources at delayed times. Our findings do not imply that there cannot be a contribution from mergers of neutron stars in other environments, as in the halo or in dwarf spheroidal galaxies, but such a contribution is not needed to explain Eu abundances at thin disc metallicities., 20 pages, accepted for publication in A&A

Published
2023

7. Neutron-induced cross section measurements

Author

C. Massimi, O. Aberle, V. Alcayne, S. Altieri, S. Amaducci, J. Andrzejewski, V. Babiano-Suarez, M. Bacak, J. Balibrea, C. Beltrami, S. Bennett, A. P. Bernardes, E. Berthoumieux, M. Boromiza, D. Bosnar, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, 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, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, Z. Eleme, S. Fargier, B. Fernández, B. Fernández-Domínguez, P. Finocchiaro, S. Fiore, V. Furman, F. GarcíaInfantes, 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, G. Kaur, A. Kimura, I. Knapová, M. Kokkoris, Y. Kopatch, M. Krtička, N. Kyritsis, I. Ladarescu, C. Lederer-Woods, J. Lerendegui-Marco, G. Lerner, A. Manna, T. Martínez, A. Masi, 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, 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. E. Stamati, A. Sturniolo, G. Tagliente, D. Tarrío, P. Torres-Sánchez, S. Urlass, 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, Freeman, S., Lederer-Woods, C., Manna, A., and Mengoni, A.

Subjects
Subatomär fysik, cross section, n_TOF, neutron time of flight, Subatomic Physics, General Medicine
Abstract

Neutron-induced cross sections represent the main nuclear input to models of stellar and Big-Bang nucleosynthesis. While (n,γ) reactions are relevant for the formation of elements heavier than iron, (n,p) and (n,α) reactions can play an important role in specific cases. The time-of-flight method is routinely used at n_TOF to experimentally determine the cross section data. In addition, recent upgrades of the facility will allow the use of activation techniques as well, possibly opening the way to a systematic study of neutron interaction with radioactive isotopes. In the last 20 years n_TOF has provided a large amount of experimental data for Nuclear Astrophysics. Our plan is to carry on challenging measurements and produce nuclear data in the next decades as well.

Published
2023

8. MINCE:I. Presentation of the project and of the first year sample

Author

G. Cescutti, P. Bonifacio, E. Caffau, L. Monaco, M. Franchini, L. Lombardo, A. M. Matas Pinto, F. Lucertini, P. François, E. Spitoni, R. Lallement, L. Sbordone, A. Mucciarelli, M. Spite, C. J. Hansen, P. Di Marcantonio, A. Kučinskas, V. Dobrovolskas, A. J. Korn, M. Valentini, L. Magrini, S. Cristallo, F. Matteucci, ITA, FRA, Cescutti, G., Bonifacio, P., Caffau, E., Monaco, L., Franchini, M., Lombardo, L., Matas Pinto, A. M., Lucertini, F., Francois, P., Spitoni, E., Lallement, R., Sbordone, L., Mucciarelli, A., Spite, M., Hansen, C. J., Di Marcantonio, P., Kucinskas, A., Dobrovolskas, V., Korn, A. J., Valentini, M., Magrini, L., Cristallo, S., and Matteucci, F.

Subjects
Galaxy halo, FOS: Physical sciences, Stars abundance, evolution [Galaxy], Abundance, Astronomi, astrofysik och kosmologi, Galaxy evolution, Astronomy, Astrophysics and Cosmology, halo [Galaxy], Abundances, atmospheres [Stars], Solar and Stellar Astrophysics (astro-ph.SR), Nucleosynthesi, Galaxy: evolution, Galaxy formation, evolution, Galaxy: formation, Galaxy: halo, stars: abundances, stars: atmospheres, nuclear reactions, nucleosynthesis, abundances, Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies [Galaxy], Stars: abundances, Astronomy and Astrophysics, Nuclear reaction, Astrophysics - Astrophysics of Galaxies, Nuclear reactions, Nucleosynthesis, Stars abundances, Stars atmospheres, formation [Galaxy], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), abundances [Stars], Stars: atmospheres
Abstract

In recent years, Galactic archaeology has become a particularly vibrant field of astronomy, with its main focus set on the oldest stars of our Galaxy. In most cases, these stars have been identified as the most metal-poor. However, the struggle to find these ancient fossils has produced an important bias in the observations - in particular, the intermediate metal-poor stars (-2.5, 21 pages, 23 figures, online material. Accepted for publication in A&A

Published
2022

9. Constraints on the dipole photon strength for the odd uranium isotopes

Author

J. Moreno-Soto, S. Valenta, E. Berthoumieux, A. Chebboubi, M. Diakaki, W. Dridi, E. Dupont, F. Gunsing, M. Krti( (c))ka, O. Litaize, O. Serot, O. Aberle, V. Alcayne, S. Amaducci, J. Andrzejewski, L. Audouin, V. B('(e))cares, V. Babiano-Suarez, M. Bacak, M. Barbagallo, Th. Benedikt, S. Bennett, J. Billowes, D. Bosnar, A. Brown, M. Busso, M. Caama(~(n))o, L. Caballero-Ontanaya, F. Calvi(~(n))o, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, E. Chiaveri, N. Colonna, G. Cort('(e))s, M. A. Cort('(e))s-Giraldo, L. Cosentino, S. Cristallo, L. A. Damone, P. J. Davies, M. Dietz, C. Domingo-Pardo, R. Dressler, Q. Ducasse, I. Dur('(a))n, Z. Eleme, B. Fern('(a))ndez-Dom('(i))nguez, A. Ferrari, P. Finocchiaro, V. Furman, K. Göbel, A. Gawlik-Rami(k(e))ga, S. Gilardoni, I. F. Gon(c(c))alves, E. Gonz('(a))lez-Romero, C. Guerrero, S. Heinitz, J. Heyse, D. G. Jenkins, A. Junghans, F. Käppeler, Y. Kadi, A. Kimura, I. Knapov('(a)), M. Kokkoris, Y. Kopatch, D. Kurtulgil, I. Ladarescu, C. Lampoudis, C. Lederer-Woods, S. J. Lonsdale, D. Macina, A. Manna, T. Mart('(i))nez, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, V. Michalopoulou, P. M. Milazzo, F. Mingrone, A. Musumarra, A. Negret, R. Nolte, F. Og('(a))llar, 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. 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. Tarife(~(n))o-Saldivia, L. Tassan-Got, P. Torres-S('(a))nchez, 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. ( (Z))ugec and, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), n_TOF, ITA, USA, GBR, FRA, DEU, Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. ANT - Advanced Nuclear Technologies Research Group, J. Moreno-Soto, S. Valenta, E. Berthoumieux, A. Chebboubi, M. Diakaki, W. Dridi, E. Dupont, F. Gunsing, M. Krti{\v{c}}ka, O. Litaize, O. Serot, O. Aberle, V. Alcayne, S. Amaducci, J. Andrzejewski, L. Audouin, V. B{\'{e}}care, V. Babiano-Suarez, M. Bacak, M. Barbagallo, Th. Benedikt, S. Bennett, J. Billowe, D. Bosnar, A. Brown, M. Busso, M. Caama{\~{n}}o, L. Caballero-Ontanaya, F. Calvi{\~{n}}o, M. Calviani, D. Cano-Ott, A. Casanova, F. Cerutti, E. Chiaveri, N. Colonna, G. Cort{\'{e}}, M. A. Cort{\'{e}}s-Giraldo, L. Cosentino, S. Cristallo, L. A. Damone, P. J. Davie, M. Dietz, C. Domingo-Pardo, R. Dressler, Q. Ducasse, I. Dur{\'{a}}n, Z. Eleme, B. Fern{\'{a}}ndez-Dom{\'{\i}}nguez, A. Ferrari, P. Finocchiaro, V. Furman, K. Göbel, A. Gawlik-Rami{\k{e}}ga, S. Gilardoni, I. F. Gon{\c{c}}alve, E. Gonz{\'{a}}lez-Romero, C. Guerrero, S. Heinitz, J. Heyse, D. G. Jenkin, A. Junghan, F. Käppeler, Y. Kadi, A. Kimura, I. Knapov{\'{a}}, M. Kokkori, Y. Kopatch, D. Kurtulgil, I. Ladarescu, C. Lampoudi, C. Lederer-Wood, S. J. Lonsdale, D. Macina, A. Manna, T. Mart{\'{\i}}nez, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, V. Michalopoulou, P. M. Milazzo, F. Mingrone, A. Musumarra, A. Negret, R. Nolte, F. Og{\'{a}}llar, A. Oprea, N. Patroni, A. Pavlik, J. Perkowski, L. Piersanti, C. Petrone, E. Pirovano, I. Porra, J. Praena, J. M. Quesada, D. Ramos-Doval, T. Rauscher, R. Reifarth, D. Rochman, M. Sabat{\'{e}}-Gilarte, A. Saxena, P. Schillebeeckx, D. Schumann, A. Sekhar, A. G. Smith, N. V. Sosnin, P. Sprung, A. Stamatopoulo, G. Tagliente, J. L. Tain, A. Tarife{\~{n}}o-Saldivia, L. Tassan-Got, P. Torres-S{\'{a}}nchez, A. Tsingani, J. Ulrich, S. Urla, G. Vannini, V. Variale, P. Vaz, A. Ventura, D. Vescovi, V. Vlachoudi, R. Vlastou, A. Wallner, P. J. Wood, T. Wright, and P. {\v{Z}}ugec and

Subjects
Física [Àrees temàtiques de la UPC], Nuclear physics, photon strength function, n_TOF, radiative capture, Nuclear Physics - Experiment, Física nuclear, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Photon strength functions (PSFs), uranium isotopes, dipole photon strength, n_TOF, Nuclear level density (NLD)
Abstract

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

Published
2022
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10. Results of the 244Cm, 246Cm and 248Cm neutron-induced capture cross sections measurements at EAR1 and EAR2 of the n_TOF facility

Author

V. Alcayne, E. Mendoza, D. Cano-Ott, A. Kimura, O. Aberle, S. Amaducci, J. Andrzejewski, L. Audouin, V. Babiano-Suarez, M. Bacak, M. Barbagallo, V. Bécares, F. Bečvář, G. Bellia, E. Berthoumieux, J. Billowes, D. Bosnar, A. S. Brown, M. Busso, M. Caamaño, L. Caballero, M. Calviani, F. Calviño, A. Casanovas, F. Cerutti, Y. H. Chen, E. Chiaveri, N. Colonna, G. P. Cortés, M. A. Cortés-Giraldo, L. Cosentino, S. Cristallo, L. A. Damone, 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. Göbel, E. González-Romero, C. Guerrero, F. Gunsing, S. Heinitz, J. Heyse, D. G. Jenkins, E. Jericha, Y. Kadi, F. Käppeler, N. Kivel, M. Kokkoris, Y. Kopatch, M. Krtička, D. Kurtulgil, I. Ladarescu, C. Lederer-Woods, J. Lerendegui-Marco, S. Lo Meo, S.-J. Lonsdale, D. Macina, A. Manna, T. Martínez, A. Masi, C. Massimi, P. F. Mastinu, M. Mastromarco, F. Matteucci, E. Maugeri, A. Mazzone, A. Mengoni, V. Michalopoulou, P. M. Milazzo, 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, P. Schillebeeckx, D. Schumann, A. G. Smith, N. Sosnin, A. Stamatopoulos, G. Tagliente, J. L. Tain, Z. Talip, A. E. Tarifeño-Saldivia, L. Tassan-Got, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, S. Valenta, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, P. J. Woods, T. J. Wright, and P. Žugec

Subjects
General Medicine
Abstract

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, critical fast reactors like Gen-IV systems, and other innovative reactor systems such as accelerator driven systems (ADS). In particular, 244Cm, 246Cm and 248Cm play a role in the transport, storage and transmutation of the nuclear waste of the current nuclear reactors, due to the contribution of these isotopes to the radiotoxicity, neutron emission, and decay heat in the spent nuclear fuel. Also, capture reactions in these Cm isotopes open the path for the formation of heavier elements. In this work, the results of the capture cross section measurement on 244Cm, 246Cm and 248Cm performed at the CERN n_TOF facility are presented. It is important to notice that the Cm samples used in the experiment at n_TOF have been used previously in an experiment at J-PARC, this experiment and the previous one done in the 70s with a nuclear explosion were the only previous capture experiments for these isotopes. At n_TOF, the capture cross section measurements of 244Cm, 246Cm and 248Cm were performed at the 20 m vertical flight path (EAR2) with three C6D6 total energy detectors. In addition, the cross section of 244Cm was measured at the 185 m flight path (EAR1) with a Total Absorption Calorimeter (TAC). The combination of measurements in EAR1 and EAR2 has contributed to controlling and reducing the systematic uncertainties in the results. The compatibility of the different measurements performed and the techniques to obtain the results are presented in this paper as well as the procedure to obtain the resonance parameters.

Published
2023

11. Overview of the dissemination of n_TOF experimental data and resonance parameters

Author

E. Dupont, N. Otuka, D. Rochman, G. Nogèure, O. Aberle, V. Alcayne, S. Altieri, S. Amaducci, J. Andrzejewski, V. Babiano-Suarez, M. Bacak, J. Balibrea, C. Beltrami, S. Bennett, A.P. Bernardes, E. Berthoumieux, R. Beyer, M. Boromiza, D. Bosnar, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, G. Cescutti, 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, C. Domingo-Pardo, R. Dressler, I. Durán, Z. Eleme, S. Fargier, B. Fernández, B. Fernández-Domínguez, P. Finocchiaro, S. Fiore, V. Furman, F. García-Infantes, A. Gawlik-Ramięga, G. Gervino, S. Gilardoni, E. González-Romero, C. Guerrero, F. Gunsing, C. Gustavino, J. Heyse, W. Hillman, G.D. 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, J. Lerendegui-Marco, G. Lerner, 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, R. Mucciola, F. Murtas, E. Musacchio-Gonzalez, A. Musumarra, A. Negret, A. Pérez de Rada, P. Pérez-Maroto, N. Patronis, J.A. Pavón-Rodrgíuez, M.G. Pellegriti, J. Perkowski, C. Petrone, E. Pirovano, J. Plaza, S. Pomp, I. Porras, J. Praena, J.M. Quesada, R. Reifarth, Y. Romanets, C. Rubbia, A. Sánchez-Caballero, M. Sabaté-Gilarte, P. Schillebeeckx, D. Schumann, A. Sekhar, A.G. Smith, N.V. Sosnin, M.E. Stamati, A. Sturniolo, G. Tagliente, A. Tarifeño-Saldivia, D. Taríro, 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, and P. Žugec

Subjects
General Medicine
Abstract

The n_TOF neutron time-of-flight facility at CERN is used for nuclear data measurements. The n_TOF Collaboration works closely with the Nuclear Reaction Data Centres (NRDC) network to disseminate the experimental data through the international EXFOR library. In addition, the Collaboration helps integrate the results in the evaluated library projects. The present contribution describes the dissemination status of n_TOF results, their impact on evaluated libraries and ongoing efforts to provide n_TOF resonance parameters in ENDF-6 format for further use by evaluation projects.

Published
2023

12. Measurement of the 241Am(n,γ) cross section at the n_TOF facility at CERN

Author

A. Oprea, F. Gunsing, P. Schillebeeckx, O. Aberle, M. Bacak, E. Berthoumieux, D. Cano-Ott, M. Diakaki, E. Dupont, B. Geslot, T. Glodariu†, J. Heyse, E. Mendoza, A. Negret, V. Alcayne, S. Amaducci, J. Andrzejewski, L. Audouin, V. Bécares, V. Babiano-Suarez, M. Barbagallo, F. Bečvář, G. Bellia, J. Billowes, D. Bosnar, A. Brown, M. Busso, M. Caamaño, L. Caballero-Ontanaya, F. Calviño, M. Calviani, A. Casanovas, F. Cerutti, Y. H. Chen, E. Chiaveri, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, S. Cristallo, L. A. Damone, M. Dietz, C. Domingo-Pardo, R. Dressler, I. Durán, Z. Eleme, B. Fernández-Domínguez, A. Ferrari, P. Finocchiaro, V. Furman, K. Göbel, R. Garg, A. Gawlik-Ramięga, S. Gilardoni, I. F. Gonçalves, E. González-Romero, C. Guerrero, H. Harada, S. Heinitz, D. G. Jenkins, E. Jericha, F. Käppeler†, G. Kaur, Y. Kadi, A. Kimura, N. Kivel, M. Kokkoris, Y. Kopatch, M. Krtička, D. Kurtulgil, I. Ladarescu, C. Lederer-Woods, H. Leeb, J. Lerendegui-Marco, S. Lo Meo, S. J. Lonsdale, D. Macina, A. Manna, T. Martínez, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, F. Matteucci, E. A. Maugeri, A. Mazzone, A. Mengoni, V. Michalopoulou, P. M. Milazzo, F. Mingrone, A. Musumarra, R. Nolte, F. Ogállar, 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, D. Schumann, A. G. Smith, N. V. Sosnin, A. Stamatopoulos, G. Tagliente, J. L. Tain, T. Talip, A. Tarifeño-Saldivia, L. Tassan-Got, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, S. Valenta, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, P. J. Woods, T. Wright, and P. Žugec

Subjects
General Medicine
Abstract

The neutron capture cross section of 241Am is an important quantity for nuclear energy production and fuel cycle scenarios. Several measurements have been performed in recent years with the aim to reduce existing uncertainties in evaluated data. Two previous measurements, performed at the 185 m flight-path station EAR1 of the neutron time-of-flight facility n_TOF at CERN, have permitted to substantially extend the resolved resonance region, but suffered in the near-thermal energy range from the unfavorable signal-to-background ratio resulting from the combination of the high radioactivity of 241Am and the rather low thermal neutron flux. The here presented 241Am(n,γ) measurement, performed with C6D6 liquid scintillator gamma detectors at the 20 m flight-path station EAR2 of the n_TOF facility, took advantage of the much higher neutron flux. The current status of the analysis of the data, focussed on the low-energy region, will be described here.

Published
2023

13. Detector set up for the measurements of the neutron-induced fission cross section of 235U relative to n-p scattering up to 150 MeV at CERN-n_TOF

Author

E. Pirovano, A. Manna, N. Colonna, P. Console Camprini, L. Cosentino, M. Dietz, Q. Ducasse, P. Finocchiaro, C. Massimi, A. Mengoni, R. Nolte, D. Radeck, L. Tassan-Got, N. Terranova, A. Ventura, 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-Ontanaya, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, E. Chiaveri, G. Cortés, M. A. Cortés-Giraldo, S. Cristallo, L. A. Damone, P. J. Davies, M. Diakaki, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, Z. Eleme, B. Fernández-Domínguez, A. Ferrari, K. Göbel, R. Garg, A. Gawlik-Ramie˛ga, 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, M. Krtička, D. Kurtulgil, I. Ladarescu, C. Lederer-Woods, H. Leeb, J. Lerendegui-Marco, S. J. Lonsdale, D. Macina, T. Martínez, A. Masi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, V. Michalopoulou, P. M. Milazzo, F. Mingrone, J. Moreno-Soto, A. Musumarra, A. Negret, F. Ogállar, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, L. Piersanti, C. Petrone, I. Porras, J. Praena, J. M. Quesada, D. Ramos-Doval, T. Rauscher, R. Reifarth, D. Rochman, C. Rubbia, 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, Th. Thomas, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, S. Valenta, G. Vannini, V. Variale, P. Vaz, D. Vescovi, V. Vlachoudis, R. Vlastou, A. Wallner, P. J. Woods, T. Wright, and P. Žugec

Subjects
General Medicine
Abstract

A new measurement of the 235U(n,f) fission cross section was carried out at n_TOF. The experiment covered the neutron energy range from 10 MeV up to 500 MeV, and it used the 1H(n,n) cross section as normalization for the neutron fluence measurement. In this contribution, the measurements and the characterization of the detectors covering the incident energy range up to 150 MeV are discussed.

Published
2023

14. Characterization of a detector setup for the measurement of the 235U(n,f) cross section relative to n-p scattering up to 500 MeV at the n_TOF facility at CERN

Author

A. Manna, E. Pirovano, N. Colonna, D. Castelluccio, P. Console Camprini, L. Cosentino, M. Dietz, Q. Ducasse, P. Finocchiaro, C. Le Naour, C. Massimi, A. Mengoni, R. Nolte, L. Tassan-Got, N. Terranova, G. Vannini, A. Ventura, 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-Ontanaya, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, E. Chiaveri, G. Cortés, M. A. Cortés-Giraldo, S. Cristallo, L. A. Damone, P. J. Davies, M. Diakaki, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, Z. Eleme, B. Fernández-Domínguez, A. Ferrari, K. Göbel, R. Garg, R. A. Gawlik-Ramiega, 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, M. Krtička, D. Kurtulgil, I. Ladarescu, C. Lederer-Woods, H. Leeb, J. Lerendegui-Marco, S. J. Lonsdale, D. Macina, T. Martínez, A. Masi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, V. Michalopoulou, P. M. Milazzo, F. Mingrone, J. Moreno-Soto, A. Musumarra, A. Negret, F. Ogállar, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, L. Piersanti, C. Petrone, I. Porras, J. Praena, J. M. Quesada, D. Ramos-Doval, T. Rauscher, R. Reifarth, D. Rochman, C. Rubbia, 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, Th. Thomas, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, S. Valenta, V. Variale, P. Vaz, D. Vescovi, V. Vlachoudis, R. Vlastou, A. Wallner, P. J. Woods, T. Wright, and P. Žugec

Subjects
General Medicine
Abstract

The measurement of the 235U(n,f) reaction cross section in the neutron energy region 10 MeV to 500 MeV was carried out at the CERN n_TOF facility. The experimental campaign, completed in 2018, provided precise and accurate data on the fission reaction relative to neutron-proton elastic scattering. A description and characterization of the used setup for the simultaneous measurement of fission fragments and neutron flux is reported here.

Published
2023

15. Review and new concepts for neutron-capture measurements of astrophysical interest

Author

M. Sabaté-Gilarte, A. Kimura, A. Segarr, J. Lerendegui-Marco, M. Krtička, T. Martinez, M. Busso, M. Mastromarco, L. Caballero, J. L. Tain, G. Tagliente, Mario Barbagallo, Z. Eleme, D. Schumann, I. Knapova, S. Bennett, B. Fernandez-Domingez, G. Vannini, P. Vaz, P. Sprung, A. Masi, F. Ogallar, A. Saxena, F. Gunsing, V. Michalopoulou, J. Heyse, A. Stamatopoulos, N. Patronis, A. Casanovas, D. G. Jenkins, Alberto Ventura, E. Jericha, E. Berthoumieux, Javier Praena, B. Thomas, A. Negret, Cristian Massimi, Alberto Mengoni, I. Ferro-Goncalves, P. J. Davies, M. A. Cortés-Giraldo, C. Rubbia, P. M. Milazzo, Paolo Finocchiaro, G. Cortes, D. R. Doval, E. Mendoza, S. Urlass, Alfredo Ferrari, J. Balibrea-Correa, J. Moreno-Soto, D. Rochman, L. Cosentino, N. V. Sosnin, A. Mazzone, M. Kokkoris, E. Maugeri, P. F. Mastinua, A. Oprea, Rene Reifarth, C. Petrone, Claudia Lederer-Woods, V. Variale, Arnd R. Junghans, P. Torres-Sanchez, A. Sekhar, M. Diakaki, U. Jiri, F. Mingrone, S. Amaducci, M. Bacak, J. M. Quesada, L. Tassan-Got, Deniz Kurtulgil, J. Andrzejewski, M. Caamaño, E. Chiaveri, V. Babiano-Suarez, D. Cano-Ott, D. Macina, F. Cerutti, V. Vlachoudis, I. Ladarescu, L. Audouin, Carlos Guerrero, L. Piersanti, A. Pavlik, A. S. Brown, R. Garg, C. Domingo-Pardo, E. González-Romero, I. Porras, Ariel Tarifeño-Saldivia, S. J. Lonsdale, M. T. Rodriguez-Gonzalez, O. Aberle, V. Furman, Y. Kopatch, A. Tsinganis, Simone Gilardoni, F. Calviño, E. Pirovano, Nicola Colonna, J. Perkowski, E. Dupont, M. A. Millán-Callado, K. Göbel, S. Cristallo, T. Wright, Diego Vescovi, F. Käppeler, A. Musumarra, R. Vlastou, Damir Bosnar, Y. Kadi, A. Manna, Q. Ducasse, S. Valenta, P. Zugec, Marco Calviani, A. G. Smith, M. Dietz, Philip Woods, Anton Wallner, P. Schillebeeckx, A. Gawlik, L. A. Damone, I. Duran, R. Dressler, V. Alcayne, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, n_TOF, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Domingo-Pardo, C., Babiano-Suarez, V., Balibrea-Correa, J., Caballero, L., Ladarescu, I., Lerendegui-Marco, J., Tain, J. L., Calvino, F., Casanovas, A., Segarr, A., Tarifeno-Saldivia, A. E., Guerrero, C., Millan-Callado, M. A., Quesada, J. M., Rodriguez-Gonzalez, M. T., Aberle, O., Alcayne, V., Amaducci, S., Andrzejewski, J., Audouin, L., Bacak, M., Barbagallo, M., Bennett, S., Berthoumieux, E., Bosnar, D., Brown, A. S., Busso, M., Caamano, M., Calviani, M., Cano-Ott, D., Cerutti, F., Chiaveri, E., Colonna, N., Cortes, G. P., Cortes-Giraldo, M. A., Cosentino, L., Cristallo, S., Damone, L. A., Davies, P. J., Diakaki, M., Dietz, M., Dressler, R., Ducasse, Q., Dupont, E., Duran, I., Eleme, Z., Fernandez-Domingez, B., Ferrari, A., Ferro-Goncalves, I., Finocchiaro, P., Furman, V., Garg, R., Gawlik, A., Gilardoni, S., Gobel, K., Gonzalez-Romero, E., Gunsing, F., Heyse, J., Jenkins, D. G., Jericha, E., Jiri, U., Junghans, A., Kadi, Y., Kappeler, F., Kimura, A., Knapova, I., Kokkoris, M., Kopatch, Y., Krticka, M., Kurtulgil, D., Lederer-Woods, C., Lonsdale, S. -J., Macina, D., Manna, A., Martinez, T., Masi, A., Massimi, C., Mastinua, P. F., Mastromarco, M., Maugeri, E., Mazzone, A., Mendoza, E., Mengoni, A., Michalopoulou, V., Milazzo, P. M., Mingrone, F., Moreno-Soto, J., Musumarra, A., Negret, A., Ogallar, F., Oprea, A., Patronis, N., Pavlik, A., Perkowski, J., Petrone, C., Piersanti, L., Pirovano, E., Porras, I., Praena, J., Doval, D. R., Reifarth, R., Rochman, D., Rubbia, C., Sabate-Gilarte, M., Saxena, A., Schillebeeckx, P., Schumann, D., Sekhar, A., Smith, A. G., Sosnin, N., Sprung, P., Stamatopoulos, A., Tagliente, G., Tassan-Got, L., Thomas, B., Torres-Sanchez, P., Tsinganis, A., Urlass, S., Valenta, S., Vannini, G., Variale, V., Vaz, P., Ventura, A., Vescovi, D., Vlachoudis, V., Vlastou, R., Wallner, A., Woods, P. J., Wright, T. J., Zugec, P., Domingo-Pardo C., Babiano-Suarez V., Balibrea-Correa J., Caballero L., Ladarescu I., Lerendegui-Marco J., Tain J.L., Calvino F., Casanovas A., Segarr A., Tarifeno-Saldivia A.E., Guerrero C., Millan-Callado M.A., Quesada J.M., Rodriguez-Gonzalez M.T., Aberle O., Alcayne V., Amaducci S., Andrzejewski J., Audouin L., Bacak M., Barbagallo M., Bennett S., Berthoumieux E., Bosnar D., Brown A.S., Busso M., Caamano M., Calviani M., Cano-Ott D., Cerutti F., Chiaveri E., Colonna N., Cortes G.P., Cortes-Giraldo M.A., Cosentino L., Cristallo S., Damone L.A., Davies P.J., Diakaki M., Dietz M., Dressler R., Ducasse Q., Dupont E., Duran I., Eleme Z., Fernandez-Domingez B., Ferrari A., Ferro-Goncalves I., Finocchiaro P., Furman V., Garg R., Gawlik A., Gilardoni S., Gobel K., Gonzalez-Romero E., Gunsing F., Heyse J., Jenkins D.G., Jericha E., Jiri U., Junghans A., Kadi Y., Kappeler F., Kimura A., Knapova I., Kokkoris M., Kopatch Y., Krticka M., Kurtulgil D., Lederer-Woods C., Lonsdale S.-J., Macina D., Manna A., Martinez T., Masi A., Massimi C., Mastinua P.F., Mastromarco M., Maugeri E., Mazzone A., Mendoza E., Mengoni A., Michalopoulou V., Milazzo P.M., Mingrone F., Moreno-Soto J., Musumarra A., Negret A., Ogallar F., Oprea A., Patronis N., Pavlik A., Perkowski J., Petrone C., Piersanti L., Pirovano E., Porras I., Praena J., Doval D.R., Reifarth R., Rochman D., Rubbia C., Sabate-Gilarte M., Saxena A., Schillebeeckx P., Schumann D., Sekhar A., Smith A.G., Sosnin N., Sprung P., Stamatopoulos A., Tagliente G., Tassan-Got L., Thomas B., Torres-Sanchez P., Tsinganis A., Urlass S., Valenta S., Vannini G., Variale V., Vaz P., Ventura A., Vescovi D., Vlachoudis V., Vlastou R., Wallner A., Woods P.J., Wright T.J., and Zugec P.

Subjects
History, Physics - Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Measure (physics), FOS: Physical sciences, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Education, Nuclear physics, Nucleosynthesis, 0103 physical sciences, Neutron, 14. Life underwater, Instrumentation (computer programming), [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Detectors and Experimental Techniques, 010306 general physics, physics.ins-det, 010303 astronomy & astrophysics, Stellar evolution, Physics, neutron capture, detector, TOF, Detector, Instrumentation and Detectors (physics.ins-det), Computer Science Applications, Progressive refinement, Neutron capture, astrophysics, neutron capture, neutron time of flight, n_TOF
Abstract

The idea of slow-neutron capture nucleosynthesis formulated in 1957 triggered a tremendous experimental effort in different laboratories worldwide to measure the relevant nuclear physics input quantities, namely (n, γ) cross sections over the stellar temperature range (from few eV up to several hundred keV) for most of the isotopes involved from Fe up to Bi. A brief historical review focused on total energy detectors will be presented to illustrate how advances in instrumentation have led to the assessment of new aspects of s-process nucleosynthesis and to the progressive refinement of stellar models. A summary will be presented on current efforts to develop new detection concepts, such as the Total-Energy Detector with γ-ray imaging capability (i-TED). The latter is based on the simultaneous combination of Compton imaging with neutron time-of-flight (TOF) techniques, in order to achieve a superior level of sensitivity and selectivity in the measurement of stellar neutron capture rates., European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (ERC Consolidator Grant project HYMNS) 681740, Instituto de Salud Carlos III Spanish Government FPA2014-52823-C2-1-P FPA2017-83946-C2-1-P, Consejo Superior de Investigaciones Cientificas (CSIC) PIE-201750I26, Program Severo Ochoa SEV-2014-0398

Published
2020

16. Neutron Capture on the s -Process Branching Point Tm 171

Author

C. Guerrero, J. Lerendegui-Marco, M. Paul, M. Tessler, S. Heinitz, C. Domingo-Pardo, S. Cristallo, R. Dressler, S. Halfon, N. Kivel, U. Köster, E. A. Maugeri, T. Palchan-Hazan, J. M. Quesada, D. Rochman, D. Schumann, L. Weissman, O. Aberle, S. Amaducci, J. Andrzejewski, L. Audouin, V. Bécares, M. Bacak, J. Balibrea, A. Barak, M. Barbagallo, S. Barros, F. Bečvář, C. Beinrucker, D. Berkovit

Published
2020
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17. Impact of a revised 25Mg(p, γ)26Al reaction rate on the operation of the Mg-Al cycle

Author

O. Straniero, G. Imbriani, F. Strieder, D. Bemmerer, C. Broggini, A. Caciolli, P. Corvisiero, H. Costantini, S. Cristallo, A. Dileva, A. Formicola, Elekes Z. Fülöp, G. Gervino, A. Guglielmetti, C. Gustavino, G. Gyürky, M. Junker, A. Lemut, B. Limata, M. Marta, C. Mazzocchi, R. Menegazzo, L. Piersanti, P. Prati, V. Roca, C. Rolfs, C. Rossi Alvarez, E. Somorjai, H. P. Trautvetter, H. P., TERRASI, Filippo, O., Straniero, G., Imbriani, F., Strieder, D., Bemmerer, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, S., Cristallo, A., Dileva, A., Formicola, Elekes Z., Fülöp, G., Gervino, A., Guglielmetti, C., Gustavino, G., Gyürky, M., Junker, A., Lemut, B., Limata, M., Marta, C., Mazzocchi, R., Menegazzo, L., Piersanti, P., Prati, V., Roca, C., Rolf, C., Rossi Alvarez, E., Somorjai, Terrasi, Filippo, H. P., Trautvetter, and H., P.

Published
2013

18. NGC 1866: a milestone for understanding the chemical evolution of stellar populations in the Large Magellanic Cloud

Author

MUCCIARELLI, ALESSIO, S. Cristallo, E. Brocato, L. Pasquini, O. Straniero, E. Caffau, G. Raimondo, A. Kaufer, I. Musella, V. Ripepi, M. Romaniello, A. R. Walker, A. Mucciarelli, S. Cristallo, E. Brocato, L. Pasquini, O. Straniero, E. Caffau, G. Raimondo, A. Kaufer, I. Musella, V. Ripepi, M. Romaniello, and A. R. Walker

Subjects
Stars: abundance, Magellanic Cloud, Techniques: spectroscopic, Astrophysics::Cosmology and Extragalactic Astrophysics, Spectroscopic, Galaxies, Stars, Techniques, NGC 1866, Globular clusters, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Abundances, Large Magellanic Clouds (LMC), Globular clusters: individual: NGC 1866, Astrophysics::Galaxy Astrophysics
Abstract

We present new FLAMES@VLT spectroscopic observations of 30 stars in the field of the LMC stellar cluster NGC 1866. NGC 1866 is one of the few young and massive globular cluster that is close enough so that its stars can be individually studied in detail. Radial velocities have been used to separate stars belonging to the cluster and to the LMC field and the same spectra have been used to derive chemical abundances for a variety of elements, from [Fe/H] to the light (i.e. Na, O, Mg...) to the heavy ones. The average iron abundance of NGC 1866 turns out to be [Fe/H]= -0.43+-0.01 dex (with a dispersion of 0.04 dex), from the analysis of 14 cluster-member stars. Within our uncertainties, the cluster stars are homogeneous, as far as chemical composition is concerned, independent of the evolutionary status. The observed cluster stars do not show any sign of the light elements 'anti-correlation' present in all the Galactic globular clusters so far studied, and also found in the old LMC stellar clusters. A similar lack of anti-correlations has been detected in the massive intermediate-age LMC clusters, indicating a different formation/evolution scenario for the LMC massive clusters younger than ~3 Gyr with respect to the old ones. Also opposite to the Galactic globulars, the chemical composition of the older RGB field stars and of the young post-MS cluster stars show robust homogeneity suggesting a quite similar process of chemical evolution. The field and cluster abundances are in agreement with recent chemical analysis of LMC stars, which show a distinctive chemical pattern for this galaxy with respect to the Milky Way. We discuss these findings in light of the theoretical scenario of chemical evolution of the LMC., Part of this work has been supported by the Spanish Ministry of Science and Innovation projects AYA2008-04211-C02-02.

Published
2010

19. Proton-capture Nucleosynthesis In Low Mass Stars: Effects of New Reaction Rates

Author

S. Palmerini, M. Busso, M. La Cognata, S. Cristallo, Paraskevi Demetriou, Rauno Julin, and Sotirios Harissopulos

Subjects
Nuclear reaction, Physics, Circumstellar shells, Masses, circumstellar masers, Stellar mass, Red giant, Radiative capture, Metallicity, formation, and abundances of the elements, clouds, Astrophysics, Giant star, Nuclear physics, Reaction rate, Stars, Origin, Nucleosynthesis, and expanding envelopes, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Nuclear Experiment, Astrophysics::Galaxy Astrophysics
Abstract

We present computations of nucleosynthesis in low‐mass asymptotic‐giant‐branch stars of solar metallicity experiencing deep mixing. In this framework, we discuss the effects of recent improvements in relevant reaction rates for proton captures on intermediate‐mass nuclei. The calculations are then performed on the basis of a parameterized circulation, where the effects of the new nuclear inputs are best compared to previous works. We find that especially the new reaction rate for the 14N(p,γ)15O reaction implies considerable modifications in the composition of low mass red giant stars.

Published
2011

20. Progresses in AGB Modelling

Author

S. Cristallo, O. Straniero, R. Gallino, M. T. Lederer, L. Piersanti, I. Domínguez, Roald Guandalini, Sara Palmerini, and Maurizio Busso

Subjects
Physics, Convection, Stars, Nucleosynthesis, Milky Way, Astrophysics::Solar and Stellar Astrophysics, Astronomy, Astrophysics, Dredge-up, Low Mass, Giant star, Stellar evolution, Astrophysics::Galaxy Astrophysics
Abstract

The full understanding of final stellar evolution phases is a fundamental request to properly investigate the Universe at any temporal and spatial scale. While the theoretical scenarios of H‐ and He‐burning have been deeply investigated in the last 30 years, the modelling of stellar evolution beyond the core‐helium burning phase and the related nucleosynthesis still present problems related to the physics and to the numerical methods. Low mass AGB Stars (1

Published
2008

21. Analysis of Two Carbon Stars in the Carina Dwarf Spheroidal Galaxy

Author

C. Abia, P. de Laverny, R. Wahlin, I. Domínguez, S. Cristallo, O. Straniero, Roald Guandalini, Sara Palmerini, and Maurizio Busso

Subjects
Physics, Spiral galaxy, K-type main-sequence star, Stellar collision, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Carbon star, Dwarf spheroidal galaxy, T Tauri star, Stellar mass loss, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Dwarf galaxy
Abstract

We present a chemical analysis of two metal‐poor carbon stars belonging to the Carina Dwarf Spheroidal galaxy using high resolution optical spectra obtained with the VLT/UVES instrument. Their derived properties and chemical composition are compatible with these stars being in the TP‐AGB phase undergoing third dredge‐up episodes, although their extrinsic nature cannot be definitively discarded. The analysis indicates that these stars have large s‐element enhancements, which are compatible with theoretical s‐process nucleosynthesis predictions in low‐mass AGB stars (∼1.5M⊙), and also large carbon enhancements (C/O⩾5), much larger than the values typically found in galactic AGB carbon stars (C/O∼1–2). This is also in agreement with the theoretical prediction that carbon stars are formed more easily through third dredge‐up episodes as the initial stellar metallicity drops. We speculate on the possibility that the abundance pattern found in the low‐mass s‐elements (Y, Zr) may be revealing the existence of som...

Published
2008

22. Observing Third Dredge Up in NGC 1846

Author

T. Lebzelter, K. H. Hinkle, M. T. Lederer, S. Cristallo, O. Straniero, W. Nowotny, P. Wood, Roald Guandalini, Sara Palmerini, and Maurizio Busso

Subjects
Physics, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Horizontal branch, Dredge-up, Giant star, Blue straggler, Luminosity, Stars, Globular cluster, Astrophysics::Solar and Stellar Astrophysics, Stellar evolution, Astrophysics::Galaxy Astrophysics
Abstract

In this contribution we present the first measurements of the C/O ratio for a sample of AGB stars in the LMC globular cluster NGC 1846. From a variability study we set strong constraints on the mass of the cluster stars, which is an important quantity for comparison with evolutionary models. Variations of the surface abundance both with luminosity and pulsation properties were found and the various relevant factors are discussed. We find a good agreement with our synthetic models if we assume [O/Fe] = ±0.2 dex. The F abundance seems to increase with the C/O ratio. As variability plays a key role on the AGB we give some preliminary results from our study of abundance determination in the dynamical case at the end of this paper.

Published
2008

23. Abundances of Heavy Elements in PNe and AGB Model Predictions

Author

M. Pignatari, R. Gallino, S. Cristallo, O. Straniero, Roald Guandalini, Sara Palmerini, and Maurizio Busso

Subjects
Physics, Nebula, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Giant star, Planetary nebula, Protoplanetary nebula, Stars, Emission nebula, Nucleosynthesis, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Stellar evolution, Astrophysics::Galaxy Astrophysics
Abstract

During the AGB phase of low and intermediate mass stars heavy s–process elements are produced and dredged–up in the envelope. In the following Planetary Nebula phase part of the AGB envelope will form the nebula around the hot central star, carrying the s–process signature unchanged. Recently, heavy elements have been observed is many Planetary Nebulae, providing a new tool to analyze the s–process nucleosynthesis working in the AGB stars. In this paper we present s–process predictions for a large spread of stellar masses, metallicities and 13C–pocket efficiencies. Theoretical results are compared with the most recent observations in PNe, finding a general good agreement.

Published
2008

24. On the Origin of Early Solar System Radioactivities: Problems with the Asymptotic Giant Branch and Massive Star Scenarios.

Author

D. Vescovi, M. Busso, S. Palmerini, O. Trippella, S. Cristallo, L. Piersanti, A. Chieffi, M. Limongi, P. Hoppe, and K.-L. Kratz

Subjects
GIANT stars, SUPERGIANT stars, SOLAR system, RADIOISOTOPES, NEUTRON stars
Abstract

Recent improvements in stellar models for intermediate-mass stars and massive stars (MSs) are recalled, together with their expectations for the synthesis of radioactive nuclei of lifetimes τ ≲ 25 Myr, in order to re-examine the origins of now extinct radioactivities that were alive in the solar nebula. The Galactic inheritance broadly explains most of them, especially if r-process nuclei are produced by neutron star merging, according to recent models. Instead, 26Al, 41Ca, 135Cs, and possibly 60Fe require nucleosynthetic events close to the solar formation. We outline the persisting difficulties to account for these nuclei by intermediate-mass stars (2 ≲ M/M⊙ ≲ 7–8). Models of their final stages now predict the ubiquitous formation of a 13C reservoir as a neutron capture source; hence, even in the presence of 26Al production from deep mixing or hot bottom burning, the ratio 26Al/107Pd remains incompatible with measured data, with a large excess in 107Pd. This is shown for two recent approaches to deep mixing. Even a late contamination by an MS encounters problems. In fact, the inhomogeneous addition of supernova debris predicts nonmeasured excesses on stable isotopes. Revisions invoking specific low-mass supernovae and/or the sequential contamination of the presolar molecular cloud might be affected by similar problems, although our conclusions here are weakened by our schematic approach to the addition of SN ejecta. The limited parameter space that remains to be explored for solving this puzzle is discussed. [ABSTRACT FROM AUTHOR]

Published
2018
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25. The Importance of the 13C(α,n)16O Reaction in Asymptotic Giant Branch Stars.

Author

S. Cristallo, M. La Cognata, C. Massimi, A. Best, S. Palmerini, O. Straniero, O. Trippella, M. Busso, G. F. Ciani, F. Mingrone, L. Piersanti, and D. Vescovi

Subjects
*ASYMPTOTIC giant branch stars, *INTERSTELLAR medium, *RED giants, *NEUTRON capture, *NEUTRON sources
Abstract

Low-mass asymptotic giant branch stars are among the most important polluters of the interstellar medium. In their interiors, the main component (A ≳ 90) of the slow neutron capture process (the s-process) is synthesized, the most important neutron source being the 13C(α,n)16O reaction. In this paper, we review its current experimental status, discussing possible future synergies between some experiments currently focused on the determination of its rate. Moreover, in order to determine the level of precision needed to fully characterize this reaction, we present a theoretical sensitivity study, carried out with the FUNS evolutionary stellar code and the NEWTON post-process code. We modify the rate up to a factor of 2 with respect to a reference case. We find that variations of the 13C(α,n)16O rate do not appreciably affect s-process distributions for masses above 3 M⊙ at any metallicity. Apart from a few isotopes, in fact, the differences are always below 5%. The situation is completely different if some 13C burns in a convective environment: this occurs in FUNS models with M < 3 M⊙ at solar-like metallicities. In this case, a change of the 13C(α,n)16O reaction rate leads to nonnegligible variations of the element surface distribution (10% on average), with larger peaks for some elements (such as rubidium) and neutron-rich isotopes (such as 86Kr and 96Zr). Larger variations are found in low-mass, low-metallicity models if protons are mixed and burned at very high temperatures. In this case, the surface abundances of the heavier elements may vary by more than a factor of 50. [ABSTRACT FROM AUTHOR]

Published
2018
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26. CONSTRAINTS OF THE PHYSICS OF LOW-MASS AGB STARS FROM CH AND CEMP STARS.

Author

S. Cristallo, D. Karinkuzhi, A. Goswami, L. Piersanti, and D. Gobrecht

Subjects
*ASYMPTOTIC giant branch stars, *STELLAR evolution, *STELLAR mass, *NUCLEAR reactions, *NUCLEOSYNTHESIS, *THERMODYNAMICS
Abstract

We analyze a set of published elemental abundances from a sample of CH stars which are based on high resolution spectral analysis of ELODIE and SUBARU/HDS spectra. All the elemental abundances were derived from local thermodynamic equilibrium analysis using model atmospheres, and thus they represent the largest homogeneous abundance data available for CH stars to date. For this reason, we can use the set to constrain the physics and the nucleosynthesis occurring in low mass asymptotic giant branch (AGB) s.tars. CH stars have been polluted in the past from an already extinct AGB companion and thus show s-process enriched surfaces. We discuss the effects induced on the surface AGB s-process distributions by different prescriptions for convection and rotation. Our reference theoretical FRUITY set fits only part of the observations. Moreover, the s-process observational spread for a fixed metallicity cannot be reproduced. At [Fe/H] > −1, a good fit is found when rotation and a different treatment of the inner border of the convective envelope are simultaneously taken into account. In order to increase the statistics at low metallicities, we include in our analysis a selected number of CEMP stars and, therefore, we compute additional AGB models down to [Fe/H] = −2.85. Our theoretical models are unable to attain the large [hs/ls] ratios characterizing the surfaces of those objects. We speculate on the reasons for such a discrepancy, discussing the possibility that the observed distribution is a result of a proton mixing episode leading to a very high neutron density (the so-called i-process). [ABSTRACT FROM AUTHOR]

Published
2016
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31. ON THE NEED FOR THE LIGHT ELEMENTS PRIMARY PROCESS (LEPP).

Author

S. Cristallo, C. Abia, O. Straniero, and L. Piersanti

Subjects
*LIGHT elements, *INTERSTELLAR magnetic fields, *ISOTOPES, *SOLAR system, *CHEMICAL reactions
Abstract

Extant chemical evolution models underestimate the galactic production of Sr, Y, and Zr as well as the solar system abundances of s-only isotopes with 90 A 130. To solve this problem, an additional (unknown) process has been invoked, the so-called light element primary process (LEPP). In this paper we investigate possible alternative solutions. Based on Full Network Stellar evolutionary calculations, we investigate the effects on the solar system s-only distribution induced by the inclusion of some commonly ignored physical processes (e.g., rotation) or by the variation of the treatment of convective overshoot, mass loss, and the efficiency of nuclear processes. Our main findings are (1) at the epoch of the formation of the solar system, our reference model produces supersolar abundances for the whole s-only distribution, even in the range 90 A 130, (2) within errors, the s-only distribution relative to 150Sm is flat, (3) the s-process contribution of the less massive AGB stars (M 1.5 M ) as well as of the more massive ones (M 4.0 M ) are negligible, (4) the inclusion of rotation implies a downward shift of the whole distribution with a higher efficiency for the heavy s-only isotopes, leading to a flatter s-only distribution, (5) different prescriptions on convection or mass loss produce nearly rigid shifts of the whole distribution. In summary, a variation of the standard paradigm of AGB nucleosynthesis would allow reconciliation of model predictions with solar system s-only abundances. Nonetheless, the LEPP cannot be definitely ruled out because of the uncertainties still affecting stellar and galactic chemical evolution models. [ABSTRACT FROM AUTHOR]

Published
2015
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32. Impact of a revised $^{25}$Mg(p,$\gamma$)$^{26}$Al reaction rate on the operation of the Mg-Al cycle

Author

Daniel Bemmerer, H. P. Trautvetter, Michele Marta, Gianluca Imbriani, Carlo Broggini, A. Lemut, Luciano Piersanti, H. Costantini, Oscar Straniero, Filippo Terrasi, Vincenzo Roca, Gyuri Gyürky, Frank Strieder, Paolo Prati, C. Mazzocchi, A. Guglielmetti, B. Limata, C. Gustavino, M. Junker, A. Formicola, Roberto Menegazzo, G. Gervino, C. Rolfs, C. Rossi Alvarez, Sergio Cristallo, Antonio Caciolli, E. Somorjai, Z. Elekes, P. Corvisiero, Zsolt Fülöp, A. DiLeva, O., Straniero, Imbriani, Gianluca, F., Strieder, D., Bemmerer, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, S., Cristallo, DI LEVA, Antonino, A., Formicola, Z., Eleke, Fülöp, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gyürky, G. y., M., Junker, A., Lemut, B., Limata, M., Marta, C., Mazzocchi, R., Menegazzo, L., Piersanti, P., Prati, Roca, Vincenzo, C., Rolf, C., Rossi Alvarez, E., Somorjai, F., Terrasi, and H. P., Trautvetter

Subjects
Nuclear reaction, Proton, globular clusters: general, nuclear reactions, nucleosynthesis, abundances, stars: AGB and post-AGB, stars: WolfRayet, Astronomy and Astrophysics, Space and Planetary Science, astrofisica nucleare, Astrophysics, Evoluzione stellare, Chemical kinetics, Reaction rate, Nucleosynthesis, Nuclear astrophysics, Asymptotic giant branch, Nuclear Experiment, Physics, abundances, Presolar grains, Nuclear reactions, nucleosynthesis, abundances — Stars: AGB and post-AGB — Stars: Wolf-Rayet — globular clusters: general, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H-burning regions. In particular, low-energy nuclear resonances in the $^{25}$Mg(p,$\gamma$)$^{26}$Al reaction affect the production of radioactive $^{26}$Al$^{gs}$ as well as the resulting Mg/Al abundance ratio. Reliable estimations of these quantities require precise measurements of the strengths of low-energy resonances. Based on a new experimental study performed at LUNA, we provide revised rates of the $^{25}$Mg(p,$\gamma$)$^{26}$Al$^{gs}$ and the $^{25}$Mg(p,$\gamma$)$^{26}$Al$^{m}$ reactions with corresponding uncertainties. In the temperature range 50 to 150 MK, the new recommended rate of the $^{26}$Al$^{m}$ production is up to 5 times higher than previously assumed. In addition, at T$=100$ MK, the revised total reaction rate is a factor of 2 higher. Note that this is the range of temperature at which the Mg-Al cycle operates in an H-burning zone. The effects of this revision are discussed. Due to the significantly larger $^{25}$Mg(p,$\gamma$)$^{26}$Al$^{m}$ rate, the estimated production of $^{26}$Al$^{gs}$ in H-burning regions is less efficient than previously obtained. As a result, the new rates should imply a smaller contribution from Wolf-Rayet stars to the galactic $^{26}$Al budget. Similarly, we show that the AGB extra-mixing scenario does not appear able to explain the most extreme values of $^{26}$Al/$^{27}$Al, i.e. $>10^{-2}$, found in some O-rich presolar grains. Finally, the substantial increase of the total reaction rate makes the hypothesis of a self-pollution by massive AGBs a more robust explanation for the Mg-Al anticorrelation observed in Globular-Cluster stars.

Published
2012

33. Measurement of the ^{140}Ce(n,γ) Cross Section at n&#95;TOF and Its Astrophysical Implications for the Chemical Evolution of the Universe.

Author

Amaducci S, Colonna N, Cosentino L, Cristallo S, Finocchiaro P, Krtička M, Massimi C, Mastromarco M, Mazzone A, Maugeri EA, Mengoni A, Roederer IU, Straniero O, Valenta S, Vescovi D, Aberle O, Alcayne V, Andrzejewski J, Audouin L, Babiano-Suarez V, Bacak M, Barbagallo M, Bennett S, Berthoumieux E, Billowes J, Bosnar D, Brown A, Busso M, Caamaño M, Caballero-Ontanaya L, Calviño F, Calviani M, Cano-Ott D, Casanovas A, Cerutti F, Chiaveri E, Cortés G, Cortés-Giraldo MA, Damone LA, Davies PJ, Diakaki M, Dietz M, Domingo-Pardo C, Dressler R, Ducasse Q, Dupont E, Durán I, Eleme Z, Fernández-Domínguez B, Ferrari A, Furman V, Göbel K, Garg R, Gawlik-Ramięga A, Gilardoni S, Gonçalves IF, González-Romero E, Guerrero C, Gunsing F, Harada H, Heinitz S, Heyse J, Jenkins DG, Junghans A, Käppeler F, Kadi Y, Kimura A, Knapová I, Kokkoris M, Kopatch Y, Kurtulgil D, Ladarescu I, Lederer-Woods C, Leeb H, Lerendegui-Marco J, Lonsdale SJ, Macina D, Manna A, Martínez T, Masi A, Mastinu P, Mendoza E, Michalopoulou V, Milazzo PM, Mingrone F, Moreno-Soto J, Musumarra A, Negret A, Nolte R, Ogállar F, Oprea A, Patronis N, Pavlik A, Perkowski J, Petrone C, Piersanti L, Pirovano E, Porras I, Praena J, Quesada JM, Ramos-Doval D, Rauscher T, Reifarth R, Rochman D, Rubbia C, Sabaté-Gilarte M, Saxena A, Schillebeeckx P, Schumann D, Sekhar A, Smith AG, Sosnin NV, Sprung P, Stamatopoulos A, Tagliente G, Tain JL, Tarifeño-Saldivia A, Tassan-Got L, Thomas T, Torres-Sánchez P, Tsinganis A, Ulrich J, Urlass S, Vannini G, Variale V, Vaz P, Ventura A, Vlachoudis V, Vlastou R, Wallner A, Woods PJ, Wright T, and Žugec P

Abstract

^{140}Ce(n,γ) 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&#95;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.

Published
2024
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34. Direct Measurement of the ^{13}C(α,n)^{16}O Cross Section into the s-Process Gamow Peak.

Author

Ciani GF, Csedreki L, Rapagnani D, Aliotta M, Balibrea-Correa J, Barile F, Bemmerer D, Best A, Boeltzig A, Broggini C, Bruno CG, Caciolli A, Cavanna F, Chillery T, Colombetti P, Corvisiero P, Cristallo S, Davinson T, Depalo R, Di Leva A, Elekes Z, Ferraro F, Fiore E, Formicola A, Fülöp Z, Gervino G, Guglielmetti A, Gustavino C, Gyürky G, Imbriani G, Junker M, Lugaro M, Marigo P, Masha E, Menegazzo R, Mossa V, Pantaleo FR, Paticchio V, Perrino R, Piatti D, Prati P, Schiavulli L, Stöckel K, Straniero O, Szücs T, Takács MP, Terrasi F, Vescovi D, and Zavatarelli S

Abstract

One of the main neutron sources for the astrophysical s process is the reaction ^{13}C(α,n)^{16}O, taking place in thermally pulsing asymptotic giant branch stars at temperatures around 90 MK. To model the nucleosynthesis during this process the reaction cross section needs to be known in the 150-230 keV energy window (Gamow peak). At these sub-Coulomb energies, cross section direct measurements are severely affected by the low event rate, making us rely on input from indirect methods and extrapolations from higher-energy direct data. This leads to an uncertainty in the cross section at the relevant energies too high to reliably constrain the nuclear physics input to s-process calculations. We present the results from a new deep-underground measurement of ^{13}C(α,n)^{16}O, covering the energy range 230-300 keV, with drastically reduced uncertainties over previous measurements and for the first time providing data directly inside the s-process Gamow peak. Selected stellar models have been computed to estimate the impact of our revised reaction rate. For stars of nearly solar composition, we find sizeable variations of some isotopes, whose production is influenced by the activation of close-by branching points that are sensitive to the neutron density, in particular, the two radioactive nuclei ^{60}Fe and ^{205}Pb, as well as ^{152}Gd.

Published
2021
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35. Neutron Capture on the s-Process Branching Point ^{171}Tm via Time-of-Flight and Activation.

Author

Guerrero C, Lerendegui-Marco J, Paul M, Tessler M, Heinitz S, Domingo-Pardo C, Cristallo S, Dressler R, Halfon S, Kivel N, Köster U, Maugeri EA, Palchan-Hazan T, Quesada JM, Rochman D, Schumann D, Weissman L, Aberle O, Amaducci S, Andrzejewski J, Audouin L, Bécares V, Bacak M, Balibrea J, Barak A, Barbagallo M, Barros S, Bečvář F, Beinrucker C, Berkovits D, Berthoumieux E, Billowes J, Bosnar D, Brugger M, Buzaglo Y, Caamaño M, Calviño F, Calviani M, Cano-Ott D, Cardella R, Casanovas A, Castelluccio DM, Cerutti F, Chen YH, Chiaveri E, Colonna N, Cortés G, Cortés-Giraldo MA, Cosentino L, Dafna H, Damone A, Diakaki M, Dietz M, Dupont E, Durán I, Eisen Y, Fernández-Domínguez B, Ferrari A, Ferreira P, Finocchiaro P, Furman V, Göbel K, García AR, Gawlik A, Glodariu T, Gonçalves IF, González-Romero E, Goverdovski A, Griesmayer E, Gunsing F, Harada H, Heftrich T, Heyse J, Hirsh T, Jenkins DG, Jericha E, Käppeler F, Kadi Y, Kaizer B, Katabuchi T, Kavrigin P, Ketlerov V, Khryachkov V, Kijel D, Kimura A, Kokkoris M, Kriesel A, Krtička M, Leal-Cidoncha E, Lederer-Woods C, Leeb H, Lo Meo S, Lonsdale SJ, Losito R, Macina D, Manna A, Marganiec J, Martínez T, Massimi C, Mastinu P, Mastromarco M, Matteucci F, Mendoza E, Mengoni A, Milazzo PM, Millán-Callado MA, Mingrone F, Mirea M, Montesano S, Musumarra A, Nolte R, Oprea A, Patronis N, Pavlik A, Perkowski J, Piersanti L, Porras I, Praena J, Rajeev K, Rauscher T, Reifarth R, Rodríguez-González T, Rout PC, Rubbia C, Ryan JA, Sabaté-Gilarte M, Saxena A, Schillebeeckx P, Schmidt S, Shor A, Sedyshev P, Smith AG, Stamatopoulos A, Tagliente G, Tain JL, Tarifeño-Saldivia A, Tassan-Got L, Tsinganis A, Valenta S, Vannini G, Variale V, Vaz P, Ventura A, Vlachoudis V, Vlastou R, Wallner A, Warren S, Weigand M, Weiss C, Wolf C, Woods PJ, Wright T, and Žugec P

Abstract

The neutron capture cross sections of several unstable nuclides acting as branching points in the s process are crucial for stellar nucleosynthesis studies. The unstable ^{171}Tm (t&#95;{1/2}=1.92  yr) is part of the branching around mass A∼170 but its neutron capture cross section as a function of the neutron energy is not known to date. In this work, following the production for the first time of more than 5 mg of ^{171}Tm at the high-flux reactor Institut Laue-Langevin in France, a sample was produced at the Paul Scherrer Institute in Switzerland. Two complementary experiments were carried out at the neutron time-of-flight facility (n&#95;TOF) at CERN in Switzerland and at the SARAF liquid lithium target facility at Soreq Nuclear Research Center in Israel by time of flight and activation, respectively. The result of the time-of-flight experiment consists of the first ever set of resonance parameters and the corresponding average resonance parameters, allowing us to make an estimation of the Maxwellian-averaged cross sections (MACS) by extrapolation. The activation measurement provides a direct and more precise measurement of the MACS at 30 keV: 384(40) mb, with which the estimation from the n&#95;TOF data agree at the limit of 1 standard deviation. This value is 2.6 times lower than the JEFF-3.3 and ENDF/B-VIII evaluations, 25% lower than that of the Bao et al. compilation, and 1.6 times larger than the value recommended in the KADoNiS (v1) database, based on the only previous experiment. Our result affects the nucleosynthesis at the A∼170 branching, namely, the ^{171}Yb abundance increases in the material lost by asymptotic giant branch stars, providing a better match to the available pre-solar SiC grain measurements compared to the calculations based on the current JEFF-3.3 model-based evaluation.

Published
2020
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36. ^{7}Be(n,p)^{7}Li Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n&#95;TOF at CERN.

Author

Damone L, Barbagallo M, Mastromarco M, Mengoni A, Cosentino L, Maugeri E, Heinitz S, Schumann D, Dressler R, Käppeler F, Colonna N, Finocchiaro P, Andrzejewski J, Perkowski J, Gawlik A, Aberle O, Altstadt S, Ayranov M, Audouin L, Bacak M, Balibrea-Correa J, Ballof J, Bécares V, Bečvář F, Beinrucker C, Bellia G, Bernardes AP, Berthoumieux E, Billowes J, Borge MJG, Bosnar D, Brown A, Brugger M, Busso M, Caamaño M, Calviño F, Calviani M, Cano-Ott D, Cardella R, Casanovas A, Castelluccio DM, Catherall R, Cerutti F, Chen YH, Chiaveri E, Correia JGM, Cortés G, Cortés-Giraldo MA, Cristallo S, Diakaki M, Dietz M, Domingo-Pardo C, Dorsival A, Dupont E, Duran I, Fernandez-Dominguez B, Ferrari A, Ferreira P, Furman W, Ganesan S, García-Rios A, Gilardoni S, Glodariu T, Göbel K, Gonçalves IF, González-Romero E, Goodacre TD, Griesmayer E, Guerrero C, Gunsing F, Harada H, Heftrich T, Heyse J, Jenkins DG, Jericha E, Johnston K, Kadi Y, Kalamara A, Katabuchi T, Kavrigin P, Kimura A, Kivel N, Köster U, Kokkoris M, Krtička M, Kurtulgil D, Leal-Cidoncha E, Lederer-Woods C, Leeb H, Lerendegui-Marco J, Lo Meo S, Lonsdale SJ, Losito R, Macina D, Marganiec J, Marsh B, Martínez T, Masi A, Massimi C, Mastinu P, Matteucci F, Mazzone A, Mendoza E, Milazzo PM, Mingrone F, Mirea M, Musumarra A, Negret A, Nolte R, Oprea A, Patronis N, Pavlik A, Piersanti L, Piscopo M, Plompen A, Porras I, Praena J, Quesada JM, Radeck D, Rajeev K, Rauscher T, Reifarth R, Riego-Perez A, Rothe S, Rout P, Rubbia C, Ryan J, Sabaté-Gilarte M, Saxena A, Schell J, Schillebeeckx P, Schmidt S, Sedyshev P, Seiffert C, Smith AG, Sosnin NV, Stamatopoulos A, Stora T, Tagliente G, Tain JL, Tarifeño-Saldivia A, Tassan-Got L, Tsinganis A, Valenta S, Vannini G, Variale V, Vaz P, Ventura A, Vlachoudis V, Vlastou R, Wallner A, Warren S, Weigand M, Weiß C, Wolf C, Woods PJ, Wright T, and Žugec P

Abstract

We report on the measurement of the ^{7}Be(n,p)^{7}Li cross section from thermal to approximately 325 keV neutron energy, performed in the high-flux experimental area (EAR2) of the n&#95;TOF facility at CERN. This reaction plays a key role in the lithium yield of the big bang nucleosynthesis (BBN) for standard cosmology. The only two previous time-of-flight measurements performed on this reaction did not cover the energy window of interest for BBN, and they showed a large discrepancy between each other. The measurement was performed with a Si telescope and a high-purity sample produced by implantation of a ^{7}Be ion beam at the ISOLDE facility at CERN. While a significantly higher cross section is found at low energy, relative to current evaluations, in the region of BBN interest, the present results are consistent with the values inferred from the time-reversal ^{7}Li(p,n)^{7}Be reaction, thus yielding only a relatively minor improvement on the so-called cosmological lithium problem. The relevance of these results on the near-threshold neutron production in the p+^{7}Li reaction is also discussed.

Published
2018
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37. ^{7}Be(n,α)^{4}He Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n&#95;TOF at CERN.

Author

Barbagallo M, Musumarra A, Cosentino L, Maugeri E, Heinitz S, Mengoni A, Dressler R, Schumann D, Käppeler F, Colonna N, Finocchiaro P, Ayranov M, Damone L, Kivel N, Aberle O, Altstadt S, Andrzejewski J, Audouin L, Bacak M, Balibrea-Correa J, Barros S, Bécares V, Bečvář F, Beinrucker C, Berthoumieux E, Billowes J, Bosnar D, Brugger M, Caamaño M, Calviani M, Calviño F, Cano-Ott D, Cardella R, Casanovas A, Castelluccio DM, Cerutti F, Chen YH, Chiaveri E, Cortés G, Cortés-Giraldo MA, Cristallo S, Diakaki M, Domingo-Pardo C, Dupont E, Duran I, Fernandez-Dominguez B, Ferrari A, Ferreira P, Furman W, Ganesan S, García-Rios A, Gawlik A, Glodariu T, Göbel K, Gonçalves IF, González-Romero E, Griesmayer E, Guerrero C, Gunsing F, Harada H, Heftrich T, Heyse J, Jenkins DG, Jericha E, Katabuchi T, Kavrigin P, Kimura A, Kokkoris M, Krtička M, Leal-Cidoncha E, Lerendegui J, Lederer C, Leeb H, Lo Meo S, Lonsdale SJ, Losito R, Macina D, Marganiec J, Martínez T, Massimi C, Mastinu P, Mastromarco M, Mazzone A, Mendoza E, Milazzo PM, Mingrone F, Mirea M, Montesano S, Nolte R, Oprea A, Pappalardo A, Patronis N, Pavlik A, Perkowski J, Piscopo M, Plompen A, Porras I, Praena J, Quesada J, Rajeev K, Rauscher T, Reifarth R, Riego-Perez A, Rout P, Rubbia C, Ryan J, Sabate-Gilarte M, Saxena A, Schillebeeckx P, Schmidt S, Sedyshev P, Smith AG, Stamatopoulos A, Tagliente G, Tain JL, Tarifeño-Saldivia A, Tassan-Got L, Tsinganis A, Valenta S, Vannini G, Variale V, Vaz P, Ventura A, Vlachoudis V, Vlastou R, Vollaire J, Wallner A, Warren S, Weigand M, Weiß C, Wolf C, Woods PJ, Wright T, and Žugec P

Abstract

The energy-dependent cross section of the ^{7}Be(n,α)^{4}He reaction, of interest for the so-called cosmological lithium problem in big bang nucleosynthesis, has been measured for the first time from 10 meV to 10 keV neutron energy. The challenges posed by the short half-life of ^{7}Be and by the low reaction cross section have been overcome at n&#95;TOF thanks to an unprecedented combination of the extremely high luminosity and good resolution of the neutron beam in the new experimental area (EAR2) of the n&#95;TOF facility at CERN, the availability of a sufficient amount of chemically pure ^{7}Be, and a specifically designed experimental setup. Coincidences between the two alpha particles have been recorded in two Si-^{7}Be-Si arrays placed directly in the neutron beam. The present results are consistent, at thermal neutron energy, with the only previous measurement performed in the 1960s at a nuclear reactor. The energy dependence reported here clearly indicates the inadequacy of the cross section estimates currently used in BBN calculations. Although new measurements at higher neutron energy may still be needed, the n&#95;TOF results hint at a minor role of this reaction in BBN, leaving the long-standing cosmological lithium problem unsolved.

Published
2016
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