| Records |
| Author |
n_TOF Collaboration (Moreno-Soto, J. et al); Babiano-Suarez, V.; Caballero-Ontanaya, L.; Domingo-Pardo, C.; Ladarescu, I.; Tain, J.L. |
| Title |
Constraints on the dipole photon strength for the odd uranium isotopes |
Type |
Journal Article |
| Year |
2022 |
Publication |
Physical Review C |
Abbreviated Journal  |
Phys. Rev. C |
| Volume |
105 |
Issue |
2 |
Pages |
024618 - 14pp |
| Keywords |
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| Abstract |
Background: The photon strength functions (PSFs) and nuclear level density (NLD) are key ingredients for calculation of the photon interaction with nuclei, in particular the reaction cross sections. These cross sections are important especially in nuclear astrophysics and in the development of advanced nuclear technologies. Purpose: The role of the scissors mode in the M1 PSF of (well-deformed) actinides was investigated by several experimental techniques. The analyses of different experiments result in significant differences, especially on the strength of the mode. The shape of the low-energy tail of the giant electric dipole resonance is uncertain as well. In particular, some works proposed a presence of the E1 pygmy resonance just above 7 MeV. Because of these inconsistencies additional information on PSFs in this region is of great interest. Methods: The gamma-ray spectra from neutron-capture reactions on the U-234, U-236, and U-238 nuclei have been measured with the total absorption calorimeter of the n_TOF facility at CERN. The background-corrected sum-energy and multi-step-cascade spectra were extracted for several isolated s-wave resonances up to about 140 eV. Results: The experimental spectra were compared to statistical model predictions coming from a large selection of models of photon strength functions and nuclear level density. No combination of PSF and NLD models from literature is able to globally describe our spectra. After extensive search we were able to find model combinations with modified generalized Lorentzian (MGLO) E1 PSF, which match the experimental spectra as well as the total radiative widths. Conclusions: The constant temperature energy dependence is favored for a NLD. The tail of giant electric dipole resonance is well described by the MGLO model of the E1 PSF with no hint of pygmy resonance. The M1 PSF must contain a very strong, relatively wide, and likely double-resonance scissors mode. The mode is responsible for about a half of the total radiative width of neutron resonances and significantly affects the radiative cross section. |
| Address |
[Moreno-Soto, J.; Berthoumieux, E.; Dupont, E.; Gunsing, F.; Bacak, M.] Univ Paris Saclay, CEA Irfu, F-91191 Gif Sur Yvette, France, Email: jmoreno53@us.es; |
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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 Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
2469-9985 |
ISBN |
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Expedition |
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Conference |
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| Notes |
WOS:000810791100001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5278 |
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| Author |
Guadilla, V. et al; Algora, A.; Tain, J.L.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Nacher, E.; Orrigo, S.E.A.; Rubio, B.; Valencia, E. |
| Title |
Total absorption gamma-ray spectroscopy of the ss decays of Y-96gs,Y-m |
Type |
Journal Article |
| Year |
2022 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
106 |
Issue |
1 |
Pages |
014306 - 14pp |
| Keywords |
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| Abstract |
The ss decays of the ground state (gs) and isomeric state (m) of Y-96 have been studied with the total absorption gamma-ray spectroscopy technique at the Ion Guide Isotope Separator On-Line facility. The separation of the 8(+) isomeric state from the 0(-) ground state was achieved thanks to the purification capabilities of the JYFLTRAP double Penning trap system. The ss-intensity distributions of both decays have been independently determined. In the analyses the deexcitation of the 1581.6 keV level in Zr-96, in which conversion electron emission competes with pair production, has been carefully considered and found to have significant impact on the ss-detector efficiency, influencing the ss-intensity distribution obtained. Our results for Y-96gs (0(-)) confirm the large ground state to ground state ss-intensity probability, although a slightly larger value than reported in previous studies was obtained, amounting to 96.6(-2.1)(+0.3) % of the total ss intensity. Given that the decay of Y-96gs is the second most important contributor to the reactor antineutrino spectrum between 5 and 7 MeV, the impact of the present results on reactor antineutrino summation calculations has been evaluated. In the decay of Y-96m (8(+)), previously undetected ss intensity in transitions to states above 6 MeV has been observed. This shows the importance of total absorption gamma-ray spectroscopy measurements of ss decays with highly fragmented deexcitation patterns. Y-96m (8(+)) is a major contributor to reactor decay heat in uranium-plutonium and thorium-uranium fuels around 10 s after fission pulses, and the newly measured average ss and gamma energies differ significantly from the previous values in evaluated databases. The discrepancy is far above the previously quoted uncertainties. Finally, we also report on the successful implementation of an innovative total absorption gamma-ray spectroscopy analysis of the module-multiplicity gated spectra, as a first proof of principle to distinguish between decaying states with very different spin-parity values. |
| Address |
[Guadilla, V; Le Meur, L.; Fallot, M.; Briz, J. A.; Estienne, M.; Giot, L.; Porta, A.; Cucoanes, A.; Shiba, T.; Zakari-Issoufou, A-A] Univ Nantes, Subatech, IMT Atlantique, CNRS IN2P3, F-44307 Nantes, France, Email: vguadilla@fuw.edu.pl |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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Original Title |
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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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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000832364800001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5313 |
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| Author |
Wu, J. et al; Algora, A.; Agramunt, J.; Morales, A.I.; Orrigo, S.E.A.; Tain, J.L.; Tarifeño-Saldivia, A.; Tolosa-Delgado, A. |
| Title |
First observation of isomeric states in 111Zr, 113Nb, and 115Mo |
Type |
Journal Article |
| Year |
2022 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
106 |
Issue |
6 |
Pages |
064328 - 5pp |
| Keywords |
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| Abstract |
Isomeric states in the neutron-rich nuclei 111Zr [T1/2 = 0.10(7) μs], 113Nb [T1/2 = 0.7(4) μs], 115Mo [T1/2 = 46(3) μs] were first identified at the Radioactive Ion Beam Factory (RIBF) of RIKEN by using in-flight fission and fragmentation of a 238U beam at an energy of 345 MeV/u. This is a brief report of the gamma transitions de -exciting from isomeric states and half-lives measurements, which provides the first spectroscopy in the nuclear region of prolate-to-oblate shape-phase transition around mass A approximate to 110. |
| Address |
[Wu, J.] Brookhaven Natl Lab, Natl Nucl Data Ctr, Upton, NY 11973 USA, Email: jwu2@bnl.gov |
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Thesis |
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| Publisher |
Amer Physical Soc |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Edition |
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| ISSN |
2469-9985 |
ISBN |
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Expedition |
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Conference |
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| Notes |
WOS:000906391600002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5452 |
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| Author |
n_TOF Collaboration (Sosnin, N.V. et al.); Babiano-Suarez, V.; Caballero, L.; Domingo-Pardo, C.; Ladarescu, I.; Tain, J.L. |
| Title |
Measurement of the 77Se(n,gamma) cross section up to 200 keV at the n_TOF facility at CERN |
Type |
Journal Article |
| Year |
2023 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
107 |
Issue |
6 |
Pages |
065805 - 9pp |
| Keywords |
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| Abstract |
The 77Se(n,gamma) reaction is of importance for 77Se abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the 77Se radiative neutron capture cross section at the Neutron Time-of-Flight facility at CERN. Resonance capture kernels were derived up to 51 keV and cross sections up to 200 keV. Maxwellian-averaged cross sections were calculated for stellar temperatures between kT = 5 keV and kT = 100 keV, with uncertainties between 4.2% and 5.7%. Our results lead to substantial decreases of 14% and 19% in 77Se abundances produced through the slow neutron capture process in selected stellar models of 15M0 and 2M0, respectively, compared to using previous recommendation of the cross section. |
| Address |
[V. Sosnin, N.; Lederer-Woods, C.; Garg, R.; Dietz, M.; Murphy, A. St. J.; Lonsdale, S.; Woods, P. J.] Univ Edinburgh, Sch Phys & Astron, Edinburgh, Scotland, Email: nsosnin@ed.ac.uk |
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Thesis |
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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 Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
2469-9985 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
WOS:001023903800002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5599 |
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| Author |
n_TOF Collaboration (Tarrío, D. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. |
| Title |
Neutron-induced fission cross sections of Th-232 and U-233 up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility |
Type |
Journal Article |
| Year |
2023 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
107 |
Issue |
4 |
Pages |
044616 - 21pp |
| Keywords |
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| Abstract |
The neutron-induced fission cross sections of Th-232 and U-233 were measured relative to U-235 in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of Th-232, and from 0.7 eV in case of U-233), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (nTOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of U-233, previous results available in EXFOR, whereas in the case of Th-232 these data were obtained from our measurement, using PPACs and targets tilted 45 degrees with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL++ and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those ( p, f) data with our (n, f) data on Th-232 and U-233 and on other isotopes studied earlier at nTOF using the same experimental setup. |
| Address |
[Tarrio, D.] Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden, Email: diego.tarrio@physics.uu.se |
| 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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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:001021341000001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5618 |
| Permanent link to this record |
