| Records |
| Author |
n_TOF Collaboration (Amaducci, S. et al); Babiano-Suarez, V.; Caballero-Ontanaya, L.; Domingo-Pardo, C.; Ladarescu, I.; Tain, J.L. |
| Title |
First Results of the Ce-140(n,gamma)Ce-141 Cross-Section Measurement at n_TOF |
Type |
Journal Article |
| Year |
2021 |
Publication |
Universe |
Abbreviated Journal |
Universe |
| Volume |
7 |
Issue |
6 |
Pages |
200 - 11pp |
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| Abstract |
An accurate measurement of the Ce-140(n,gamma) 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 Ce-140 capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in Ce-140 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 Ce-140 Maxwellian-averaged cross-section. |
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WOS:000665969800001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4877 |
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| Author |
Esposito, R. et al; Domingo-Pardo, C. |
| Title |
Design of the third-generation lead-based neutron spallation target for the neutron time-of-flight facility at CERN |
Type |
Journal Article |
| Year |
2021 |
Publication |
Physical Review Accelerators and Beams |
Abbreviated Journal |
Phys. Rev. Accel. Beams |
| Volume |
24 |
Issue |
9 |
Pages |
093001 - 17pp |
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| Abstract |
The neutron time-of-flight (n_TOF) facility at the European Laboratory for Particle Physics (CERN) is a pulsed white-spectrum neutron spallation source producing neutrons for two experimental areas: the Experimental Area 1 (EAR1), located 185 m horizontally from the target, and the Experimental Area 2 (EAR2), located 20 m above the target. The target, based on pure lead, is impacted by a high-intensity 20-GeV/c pulsed proton beam. The facility was conceived to study neutron-nucleus interactions for neutron kinetic energies between a few meV to several GeV, with applications of interest for nuclear astrophysics, nuclear technology, and medical research. After the second-generation target reached the end of its lifetime, the facility underwent a major upgrade during CERN's Long Shutdown 2 (LS2, 2019-2021), which included the installation of the new third-generation neutron target. The first- and second-generation targets were based on water-cooled massive lead blocks and were designed focusing on EAR1, since EAR2 was built later. The new target is cooled by nitrogen gas to avoid erosion-corrosion and contamination of cooling water with radioactive lead spallation products. Moreover, the new design is optimized also for the vertical flight path and EAR2. This paper presents an overview of the target design focused on both physics and thermomechanical performance, and includes a description of the nitrogen cooling circuit and radiation protection studies. |
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[Esposito, R.; Calviani, M.; Aberle, O.; Barbagallo, M.; Coiffet, T.; Dragoni, F.; Ximenes, R. Franqueira; Giordanino, L.; Grenier, D.; Kershaw, K.; Maire, V.; Moyret, P.; Fontenla, A. Perez; Perillo-Marcone, A.; Pozzi, F.; Sgobba, S.; Timmins, M.; Vlachoudis, V.] European Lab Particle Phys CERN, CH-1211 Geneva 23, Switzerland, Email: raffaele.esposito@cern.ch; |
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Amer Physical Soc |
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English |
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WOS:000696029700001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4963 |
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| Author |
Massimi, C.; Cristallo, S.; Domingo-Pardo, C.; Lederer-Woods, C. |
| Title |
n_TOF: Measurements of Key Reactions of Interest to AGB Stars |
Type |
Journal Article |
| Year |
2022 |
Publication |
Universe |
Abbreviated Journal |
Universe |
| Volume |
8 |
Issue |
2 |
Pages |
100 - 19pp |
| Keywords |
s process; MACS; time of flight |
| Abstract |
In the last 20 years, the neutron time-of-flight facility nTOF at CERN has been providing relevant data for the astrophysical slow neutron capture process (s process). At nTOF, neutron-induced radiative capture (n,gamma) as well as (n,p) and (n,alpha) reaction cross sections are measured as a function of energy, using the time-of-flight method. Improved detection systems, innovative ideas and collaborations with other neutron facilities have lead to a considerable contribution of the n_TOF collaboration to studying the s process in asymptotic giant branch stars. Results have been reported for stable and radioactive samples, i.e.,Mg- 24,Mg-25,Mg-26, Al-26, S-33,Fe- 54,Fe-57, Ni-58,Ni-59,Ni-62,Ni-63, Ge-70,Ge-72,Ge-73, Zr-90,Zr-91,Zr-92,Zr-93,Zr-94,Zr-96, La-139, Ce-140, Pm-147, Sm-151,Gd- 154,Gd-155,Gd-157, Tm-171, Os-186,Os-187,Os-188, Au-197, Tl-203,Tl-204,Pb- 204,Pb-206,Pb-207 and Bi-209 isotopes, while others are being studied or planned to be studied in the near future. In this contribution, we present an overview of the most successful achievements, and an outlook of future challenging measurements, including ongoing detection system developments. |
| Address |
[Massimi, Cristian] Univ Bologna, Dept Phys & Astron, I-40127 Bologna, Italy, Email: cristian.massimi@unibo.it; |
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Mdpi |
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English |
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WOS:000762514400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5144 |
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Fougeres, C. et al; Domingo-Pardo, C. |
| Title |
Search for Na-22 in novae supported by a novel method for measuring femtosecond nuclear lifetimes |
Type |
Journal Article |
| Year |
2023 |
Publication |
Nature Communications |
Abbreviated Journal |
Nat. Commun. |
| Volume |
14 |
Issue |
1 |
Pages |
4536 - 7pp |
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Classical novae are thermonuclear explosions in stellar binary systems, and important sources of Al-26 and Na-22. While ? rays from the decay of the former radioisotope have been observed throughout the Galaxy, Na-22 remains untraceable. Its half-life (2.6 yr) would allow the observation of its 1.275 MeV ?-ray line from a cosmic source. However, the prediction of such an observation requires good knowledge of its nucleosynthesis. The Na-22(p, ?)Mg-23 reaction remains the only source of large uncertainty about the amount of Na-22 ejected. Its rate is dominated by a single resonance on the short-lived state at 7785.0(7) keV in Mg-23. Here, we propose a combined analysis of particle-particle correlations and velocity-difference profiles to measure femtosecond nuclear lifetimes. The application of this method to the study of the Mg-23 states, places strong limits on the amount of Na-22 produced in novae and constrains its detectability with future space-borne observatories. The authors report a particle-particle correlation and velocity-difference profile method to measure nuclear lifetime. The results obtained for excited states of 23Mg are used to constrain the production of 22Na in the astrophysical novae explosions. |
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[Fougeres, Chloe; Santos, Francois de Oliveira; Michelagnoli, Caterina; Clement, Emmanuel; Kim, Yung Hee; Lemasson, Antoine; Boulay, Florent; Goupil, Johan; Li, Hongjie; Navin, Alahari; Ralet, Damien; Saillant, Frederic] Grand Accelerateur Natl Ions Lourds GANIL, CEA, IN2P3, DRF CNRS, Caen, France, Email: chloe.fougeres@gmail.com; |
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Nature Portfolio |
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English |
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WOS:001063751200012 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5671 |
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Kiss, G.G. et al; Tarifeño-Saldivia, A.; Tain, J.L.; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Morales, A.I.; Nacher, E.; Rubio, B.; Tolosa, A. |
| Title |
Measuring the beta-decay Properties of Neutron-rich Exotic Pm, Sm, Eu, and Gd Isotopes to Constrain the Nucleosynthesis Yields in the Rare-earth Region |
Type |
Journal Article |
| Year |
2022 |
Publication |
Astrophysical Journal |
Abbreviated Journal |
Astrophys. J. |
| Volume |
936 |
Issue |
2 |
Pages |
107 - 18pp |
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The beta-delayed neutron-emission probabilities of 28 exotic neutron-rich isotopes of Pm, Sm, Eu, and Gd were measured for the first time at RIKEN Nishina Center using the Advanced Implantation Detector Array (AIDA) and the BRIKEN neutron detector array. The existing beta-decay half-life (T (1/2)) database was significantly increased toward more neutron-rich isotopes, and uncertainties for previously measured values were decreased. The new data not only constrain the theoretical predictions of half-lives and beta-delayed neutron-emission probabilities, but also allow for probing the mechanisms of formation of the high-mass wing of the rare-earth peak located at A approximate to 160 in the r-process abundance distribution through astrophysical reaction network calculations. An uncertainty quantification of the calculated abundance patterns with the new data shows a reduction of the uncertainty in the rare-earth peak region. The newly introduced variance-based sensitivity analysis method offers valuable insight into the influence of important nuclear physics inputs on the calculated abundance patterns. The analysis has identified the half-lives of Sm-168 and of several gadolinium isotopes as some of the key variables among the current experimental data to understand the remaining abundance uncertainty at A = 167-172. |
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[Kiss, G. G.; Vitez-Sveiczer, A.; Algora, A.; Szegedi, T. N.] Inst Nucl Res ATOMKI, Bem Ter 18-c, H-4026 Debrecen, Hungary, Email: ggkiss@atomki.hu; |
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IOP Publishing Ltd |
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English |
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0004-637x |
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| Notes |
WOS:000850804600001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5353 |
| Permanent link to this record |
