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n_TOF Collaboration (Amaducci, S. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Measurement of the U-235(n, f) cross section relative to the Li-6(n, t) and B-10(n,alpha) standards from thermal to 170 keV neutron energy range at n_TOF |
Type |
Journal Article |
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Year |
2019 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
55 |
Issue |
7 |
Pages |
120 - 19pp |
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Abstract  |
.The U-235(n, f ) cross section was measured at n_TOF relative to Li-6(n, t) and B-10(n,alpha) , with high resolution ( L=183.49(2) m) and in a wide energy range (25meV-170keV) with 1.5% systematic uncertainty, making use of a stack of six samples and six silicon detectors placed in the neutron beam. This allowed us to make a direct comparison of the yields of the U-235(n, f ) and of the two reference reactions under the same experimental conditions, and taking into account the forward/backward emission asymmetry. A hint of an anomaly in the 10-30keV neutron energy range had been previously observed in other experiments, indicating a cross section systematically lower by several percent relative to major evaluations. The present results indicate that the cross section in the 9-18keV neutron energy range is indeed overestimated by almost 5% in the recently released evaluated data files ENDF/B-VIII.0 and JEFF3.3, as a consequence of a 7% overestimate in a single GMA node in the IAEA reference file. Furthermore, these new high-resolution data confirm the existence of resonance-like structures in the keV neutron energy region. The results here reported may lead to a reduction of the uncertainty in the 1-100keV neutron energy region. Finally, from the present data, a value of 249.7 +/- 1.4( stat )+/- 0.94( syst ) b<bold>eV has been extracted for the cross section integral between </bold>7.8 and 11eV, confirming the value of 247.5 +/- 3 b<bold>eV recently established as a standard</bold>. |
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Address |
[Amaducci, S.; Cosentino, L.; Finocchiaro, P.; Musumarra, A.] INFN, Lab Nazl Sud, Catania, Italy, Email: finocchiaro@lns.infn.it |
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Springer |
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English |
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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 |
1434-6001 |
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Notes |
WOS:000477050900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4083 |
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Author |
n_TOF Collaboration (Amaducci, S. et al); Babiano-Suarez, V.; Caballero-Ontanaya, L.; Domingo-Pardo, C.; Ladarescu, I.; Tain, J.L.; Tarifeño-Saldivia, A. |
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Title |
Measurement of the 140Ceðn;γþ Cross Section at n_TOF and Its Astrophysical Implications for the Chemical Evolution of the Universe |
Type |
Journal Article |
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Year |
2024 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
132 |
Issue |
12 |
Pages |
122701 - 8pp |
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Keywords |
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Abstract |
140Ce(n, gamma) 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 approximate to 5%) at the n_TOF facility, with an unprecedented combination of a high purity sample and low neutron -sensitivity detectors. The measured Maxwellian averaged cross section is up to 40% higher than previously accepted values. Stellar model calculations indicate a reduction around 20% of the s -process contribution to the Galactic cerium abundance and smaller sizeable differences for most of the heavier elements. No variations are found in the nucleosynthesis from massive stars. |
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Address |
[Amaducci, S.; Cosentino, L.; Finocchiaro, P.; Brown, A.] INFN, Lab Nazl Sud, Catania, Italy |
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Amer Physical Soc |
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English |
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Edition |
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ISSN |
0031-9007 |
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Conference |
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Notes |
WOS:001202102900011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6074 |
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Author |
Napiralla, P. et al; Domingo-Pardo, C. |
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Title |
Benchmarking the PreSPEC@GSI experiment for Coulex-multipolarimetry on the pi(p3/2) -> pi(p1/2) spin-flip transition in 85Br |
Type |
Journal Article |
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Year |
2020 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
56 |
Issue |
5 |
Pages |
147 - 10pp |
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Keywords |
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Abstract |
A first performance test of the Coulomb excitation multipolarimetry (Coulex-multipolarimetry) method is presented. It is based on a 85Br pp3/ 2. pp1/ 2 spinflip experiment performed as part of the PreSPEC-AGATA campaign at the GSI Helmholtzzentrum fur Schwerionen-forschung (GSI). Via determination of background levels around the expected 85Br excitations as well as measured 197Au excitations, an upper limit for the M1 transition strength of the 1/2- 1. 3/2- g.s. transition in 85Br and a lower beam time limit for upcoming experimental campaigns utilizing Coulex-multipolarimetry have been inferred. The impact of the use of AGATA in its anticipated 1p configuration on these estimates is deduced via Geant4 simulations. |
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Address |
[Napiralla, P.; Lettmann, M.; Stahl, C.; Pietralla, N.; Boutachkov, P.; Cortes, M. L.; John, P. R.; Lizarazo, C.; Louchart-Henning, C.; Merchan, E.; Moeller, O.; Moeller, T.; Ralet, D.; Werner, V] Tech Univ Darmstadt, Inst Kernphys, Schlossgartenstr 9, D-64289 Darmstadt, Germany, Email: pnapiralla@ikp.tu-darmstadt.de |
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Publisher |
Springer |
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 |
1434-6001 |
ISBN |
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Conference |
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Notes |
WOS:000541855500002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4441 |
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Author |
n_TOF Collaboration (Tarrio, D. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. |
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Title |
Measurement of the angular distribution of fission fragments using a PPAC assembly at CERN n_TOF |
Type |
Journal Article |
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Year |
2014 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
743 |
Issue |
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Pages |
79-85 |
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Keywords |
Fission; Neutron; Anisotropy; Angular distribution; Th-232; Gas detectors |
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Abstract |
A fission reaction chamber based on Parallel Plate Avalanche Counters (PPACs) was built for measuring angular distributions of fragments emitted in neutron-induced fission of actinides at the neutron beam available at the Neutron Time-Of-Flight (n_TOF) facility at CERN. The detectors and the samples were tilted 45 degrees with respect to the neutron beam direction to cover all the possible values of the emission angle of the fission fragments. The main features of this setup are discussed and results on the fission fragment angular distribution are provided for the Th-232(n,f) reaction around the fission threshold. The results are compared with the available data in the literature, demonstrating the good capabilities of this setup. |
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Address |
[Tarrio, D.; Duran, I.; Paradela, C.; Caamano, M.] Univ Santiago de Compostela, Santiago De Compostela, Spain, Email: dtarriov@gmail.com |
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Publisher |
Elsevier Science Bv |
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 |
0168-9002 |
ISBN |
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Conference |
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Notes |
WOS:000334005000011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1746 |
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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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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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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 |
2469-9985 |
ISBN |
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Area |
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Expedition |
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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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| Permanent link to this record |
