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Author |
Esposito, R. et al; Domingo-Pardo, C. |
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Title |
Design of the third-generation lead-based neutron spallation target for the neutron time-of-flight facility at CERN |
Type |
Journal Article |
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Year |
2021 |
Publication |
Physical Review Accelerators and Beams |
Abbreviated Journal |
Phys. Rev. Accel. Beams |
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Volume |
24 |
Issue |
9 |
Pages |
093001 - 17pp |
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Keywords |
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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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Address  |
[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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Notes |
WOS:000696029700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4963 |
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Author |
Fernandez, A. et al; Gadea, A.; Perez-Vidal, R.M.; Jurado, M.; Domingo-Pardo, C. |
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Title |
Reinterpretation of excited states in Po-212: Shell-model multiplets rather than alpha-cluster states |
Type |
Journal Article |
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Year |
2021 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
104 |
Issue |
5 |
Pages |
054316 - 19pp |
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Keywords |
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Abstract |
A gamma-ray spectroscopic study of Po-212 was performed at the Grand Accelerateur National d'Ions Lourds, using the inverse kinematics alpha-transfer reaction C-12(Pb-208, Po-212) Be-8 and the AGATA spectrometer. A careful analysis based on gamma gamma coincidence relations allowed us to establish 14 new excited states in the energy range between 1.9 and 3.3 MeV. None of these states, however, can be considered as candidates for the levels with spins and parities of 1(-) and 2(-) and excitation energies below 2.1 MeV, which have been predicted by recent alpha-cluster model calculations. A systematic comparison of the experimentally established excitation scheme of Po-212 with shell-model calculations was performed. This comparison suggests that the six states with excitation energies (spins and parities) of 1744 (4(-)), 1751 (8(-)), 1787 (6(-)), 1946 (4(-)), 1986 (8(-)), and 2016 (6(-)) keV, which previously were interpreted as alpha-cluster states, may in fact be of positive parity and belong to low-lying shell-model multiplets. This reinterpretation of the structure of Po-212 is supported by experimental information with respect to the linear polarization of gamma rays, which suggests a magnetic character of the 432-keV gamma ray decaying from the state at an excitation energy of 1787 keV to the 6(1)(+) yrast state, and exclusive reaction cross sections. |
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Address |
[Fernandez, A.; Jungclaus, A.; Nacher, E.; Perea, A.; Wimmer, K.] CSIC, Inst Estruct Mat, E-28006 Madrid, Spain, Email: andrea.jungclaus@csic.es |
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Amer Physical Soc |
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English |
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ISSN |
2469-9985 |
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Conference |
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Notes |
WOS:000726014300010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5047 |
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Author |
Fougeres, C. et al; Domingo-Pardo, C. |
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Title |
Search for Na-22 in novae supported by a novel method for measuring femtosecond nuclear lifetimes |
Type |
Journal Article |
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Year |
2023 |
Publication |
Nature Communications |
Abbreviated Journal |
Nat. Commun. |
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Volume |
14 |
Issue |
1 |
Pages |
4536 - 7pp |
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Abstract |
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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Address |
[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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Publisher |
Nature Portfolio |
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English |
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Notes |
WOS:001063751200012 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5671 |
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Author |
n_TOF Collaboration (Fraval, K. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. |
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Title |
Measurement and analysis of the Am-241(n,gamma) cross section with liquid scintillator detectors using time-of-flight spectroscopy at the n_TOF facility at CERN |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
89 |
Issue |
4 |
Pages |
044609 - 14pp |
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Keywords |
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Abstract |
The Am-241(n,gamma) cross section has been measured at the n_TOF facility at CERN using deuterated benzene liquid scintillators, commonly known as C6D6 detectors, and time-of-flight spectrometry. The results in the resolved resonance range bring new constraints to evaluations below 150 eV, and the energy upper limit was extended from 150 to 320 eV with a total of 172 new resonances not present in current evaluations. The thermal capture cross section was found to be sigma(th) = 678 +/- 68 b, which is in good agreement with evaluations and most previous measurements. The capture cross section in the unresolved resonance region was extracted in the remaining energy range up to 150 keV, and found to be larger than current evaluations and previous measurements. |
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Address |
[Fraval, K.; Gunsing, F.; Belloni, F.; Berthoumieux, E.; Lampoudis, C.] CEA Saclay, Irfu, F-91191 Gif Sur Yvette, France, Email: frank.gunsing@cea.fr |
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Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0556-2813 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000335321400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1778 |
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Author |
n_TOF Collaboration (Fujii, K. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Neutron physics of the Re/Os clock. III. Resonance analyses and stellar (n, gamma) cross sections of Os-186,Os-187,Os-188 |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
82 |
Issue |
1 |
Pages |
015804 - 18pp |
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Keywords |
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Abstract |
Neutron resonance analyses have been performed for the capture cross sections of Os-186, Os-187, and Os-188 measured at the n_TOF facility at CERN. Resonance parameters have been extracted up to 5, 3, and 8 keV, respectively, using the SAMMY code for a full R-matrix fit of the capture yields. From these results average resonance parameters were derived by a statistical analysis to provide a comprehensive experimental basis for modeling of the stellar neutron capture rates of these isotopes in terms of the Hauser-Feshbach statistical model. Consistent calculations for the capture and inelastic reaction channels are crucial for the evaluation of stellar enhancement factors to correct the Maxwellian averaged cross sections obtained from experimental data for the effect of thermally populated excited states. These factors have been calculated for the full temperature range of current scenarios of s-process nucleosynthesis using the combined information of the experimental data in the region of resolved resonances and in the continuum. The consequences of this analysis for the s-process component of the Os-187 abundance and the related impact on the evaluation of the time duration of galactic nucleosynthesis via the Re/Os cosmochronometer are discussed. |
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Address |
[Fujii, K.; Abbondanno, U.; Belloni, F.; Milazzo, P. M.; Moreau, C.] Ist Nazl Fis Nucl, I-34149 Trieste, Italy, Email: Kaori.Fujii@ts.infn.it |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0556-2813 |
ISBN |
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Conference |
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Notes |
ISI:000279940200009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
410 |
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