Records |
Author |
n_TOF Collaboration (Tagliente, G. et al.); Domingo-Pardo, C.; Tain, J.L. |
Title |
The Zr-92(n,gamma) reaction and its implications for stellar nucleosynthesis |
Type |
Journal Article |
Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
Volume |
81 |
Issue |
5 |
Pages |
055801 - 9pp |
Keywords |
|
Abstract |
Because the relatively small neutron capture cross sections of the zirconium isotopes are difficult to measure, the results of previous measurements are often not adequate for a number of problems in astrophysics and nuclear technology. Therefore, the Zr-92(n,gamma) cross section has been remeasured at the CERN n_TOF facility, providing a set of improved parameters for 44 resonances in the neutron energy range up to 40 keV. With this information the cross-section uncertainties in the keV region could be reduced to 5% as required for s-process nucleosynthesis studies and technological applications. |
Address |
[Tagliente, G.; Colonna, N.; Marrone, S.; Terlizzi, R.] Ist Nazl Fis Nucl, I-70126 Bari, Italy, Email: giuseppe.tagliente@ba.infn.it |
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 |
0556-2813 |
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 |
ISI:000278144800074 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ elepoucu @ |
Serial |
444 |
Permanent link to this record |
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Author |
Yokoyama, R. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tolosa-Delgado, A. |
Title |
β-delayed neutron emissions from N > 50 gallium isotopes |
Type |
Journal Article |
Year |
2023 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
Volume |
108 |
Issue |
6 |
Pages |
064307 - 15pp |
Keywords |
|
Abstract |
beta-delayed gamma-neutron spectroscopy has been performed on the decay of A=84 to 87 gallium isotopes at the RI-beam Factory at the RIKEN Nishina Center using a high-efficiency array of 3He neutron counters (BRIKEN). beta-2n-gamma events were measured in the decays of all of the four isotopes for the first time, which is direct evidence for populating the excited states of two-neutron daughter nuclei. Detailed decay schemes with the gamma branching ratios were obtained for these isotopes, and the neutron emission probabilities (P-xn) were updated from the previous study. Hauser-Feshbach statistical model calculations were performed to understand the experimental branching ratios. We found that the P-1n and P-2n values are sensitive to the nuclear level densities of 1n daughter nuclei and showed that the statistical model reproduced the P-2n/P-1n ratio better when experimental levels plus shell-model level densities fit by the Gilbert-Cameron formula were used as the level-density input. We also showed the neutron and gamma branching ratios are sensitive to the ground-state spin of the parent nucleus. Our statistical model analysis suggested J <= 3 for the unknown ground-state spin of the odd-odd nucleus Ga-86, from the I gamma(4(+)-> 2(+))/I-gamma(2(+)-> 0(+)) ratio of Ga-84 and the P-2n/P-1n ratio. These results show the necessity of detailed understanding of the decay scheme, including data from neutron spectroscopy, in addition to gamma measurements of the multineutron emitters. |
Address |
[Yokoyama, R.; Grzywacz, R.; Rasco, B. C.; Brewer, N.; Heideman, J.; King, T. T.; Madurga, M.; Singh, M.] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA, Email: yokoyama@cns.s.u-tokyo.ac.jp |
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 |
|
Notes |
WOS:001159167500001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5939 |
Permanent link to this record |
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Author |
Martinez, T. et al; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Jordan, M.D.; Rubio, B.; Tain, J.L. |
Title |
MONSTER: a TOF Spectrometer for beta-delayed Neutron Spectroscopy |
Type |
Journal Article |
Year |
2014 |
Publication |
Nuclear Data Sheets |
Abbreviated Journal |
Nucl. Data Sheets |
Volume |
120 |
Issue |
|
Pages |
78-80 |
Keywords |
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Abstract |
beta-delayed neutron (DN) data, including emission probabilities, P-n, and energy spectrum, play an important role in our understanding of nuclear structure, nuclear astrophysics and nuclear technologies. A MOdular Neutron time-of-flight SpectromeTER (MONSTER) is being built for the measurement of the neutron energy spectra and branching ratios. The TOF spectrometer will consist of one hundred liquid scintillator cells covering a significant solid angle. The MONSTER design has been optimized by using Monte Carlo (MC) techniques. The response function of the MONSTER cell has been characterized with mono-energetic neutron beams and compared to dedicated MC simulations. |
Address |
[Martinez, T.; Cano-Ott, D.; Castilla, J.; Garcia, A. R.; Marin, J.; Martinez, G.; Mendoza, E.; Santos, C.; Tera, F. J.; Villamarin, D.] CIEMAT, Ctr Invest Energet, Medio Ambient Tecnol, E-28040 Madrid, Spain, Email: trino.martinez@ciemat.es |
Corporate Author |
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Thesis |
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Publisher |
Academic Press Inc Elsevier Science |
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 |
0090-3752 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
|
Notes |
WOS:000339860100021 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
1872 |
Permanent link to this record |
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Author |
Domingo-Pardo, C. |
Title |
Beta-delayed neutron emission: first measurements in the heavy mass region and future prospects |
Type |
Journal Article |
Year |
2016 |
Publication |
Acta Physica Polonica B |
Abbreviated Journal |
Acta Phys. Pol. B |
Volume |
47 |
Issue |
3 |
Pages |
729-737 |
Keywords |
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Abstract |
Beta-delayed neutrons play a key role in the formation of heavy elements in explosive stellar environments. The final r-process abundance distribution, including the rare-earth peak, is tailored to a large extent by the neutrons released after the beta decay of very exotic neutron-rich nuclei encountered along the r-process path and during the freeze-out phase. Such scenarios involve a vast amount of – yet undiscovered – nuclei, and most of them are expected to be neutron emitters. In this respect, existing beta-delayed neutron emission data is rather scarce, spanning from the lightest isotopes up to the region of the fission-fragments with masses up to A similar to 150. This contribution gives an overview on the latest measurements of neutron branching ratios in the heavy mass region around N = 126, which was practically unexplored in the past. Present plans to access very exotic nuclei at the RIB-facility of RIKEN in the framework of the BRIKEN project, are presented, together with the expected impact in r-process nucleosynthesis studies. |
Address |
[Domingo-Pardo, C.; S410 GSI Collaboration; BRIKEN Collaboration] Univ Valencia, CSIC, IFIC, Valencia, Spain |
Corporate Author |
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Thesis |
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Publisher |
Wydawnictwo Uniwersytetu Jagiellonskiego |
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 |
0587-4254 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
|
Notes |
WOS:000373495500015 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
no |
Call Number |
IFIC @ pastor @ |
Serial |
2623 |
Permanent link to this record |
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Author |
Yokoyama, R. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tolosa-Delgado, A. |
Title |
Strong one-neutron emission from two-neutron unbound states in beta decays of the r-process nuclei Ga-86,Ga-87 |
Type |
Journal Article |
Year |
2019 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
Volume |
100 |
Issue |
3 |
Pages |
031302 - 6pp |
Keywords |
|
Abstract |
beta-delayed one-neutron and two-neutron branching ratios (P-1n and P-2n) have been measured in the decay of A = 84 to 87 Ga isotopes at the Radioactive-Isotope Beam Factory (RIBF) at the RIKEN Nishina Center using a high-efficiency array of He-3 neutron counters (BRIKEN). Two-neutron emission was observed in the decay of Ga-84,Ga-85,Ga-87 for the first time and the branching ratios were measured to be P-2n = 1.6(2)%, 1.3(2)%, and 10.2(28)(stat)(5)(sys)%, respectively. One-neutron branching ratio of Ga-87 (P-1n = 81(9)(stat)(8)(sys)%) and half-life of 29(4) ms were measured for the first time. The branching ratios of Ga-86 were also measured to be P-1n = 74(2)(stat)(8)(sys)% and 16.2(9)(stat)(6)(sys)% with better precision than a previous study. The observation that P-1n > P-2n for both Ga-86,Ga-87 was unexpected and is interpreted as a signature of dominating one-neutron emission from the two-neutron unbound excited states in Ge-86,Ge-87. In order to interpret the experimental results, shell-model and Hauser-Feshbach statistical model calculations of delayed particle and gamma-ray emission probabilities were performed. This model framework reproduces the experimental results. The shell model alone predicts P-2n significantly larger than P-1n for the Ga-87 decay, and it is necessary to invoke a statistical description to successfully explain the observation that P-1n > P-2n. Our new results demonstrate the relevance and importance of a statistical description of neutron emission for the prediction of the decay properties of multineutron emitters and that it must be included in the r-process modeling. |
Address |
[Yokoyama, R.; Grzywacz, R.; Rasco, B. C.; Brewer, N.; Heideman, J.; King, T. T.; Madurga, M.; Singh, M.] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA, Email: ryokoyam@utk.edu |
Corporate Author |
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Thesis |
|
Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
Language |
English |
Summary Language |
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Original Title |
|
Series Editor |
|
Series Title |
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Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
2469-9985 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
WOS:000486641000001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
4145 |
Permanent link to this record |