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Author |
Valencia, E. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Estevez, E.; Jordan, M.D.; Rubio, B. |
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Title |
Total absorption gamma-ray spectroscopy of the beta-delayed neutron emitters Br-87, Br-88, and Rb-94 |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
95 |
Issue |
2 |
Pages |
024320 - 18pp |
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Keywords |
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Abstract  |
We investigate the decay of Br-87,Br-88 and Rb-94 using total absorption gamma-ray spectroscopy. These important fission products are beta-delayed neutron emitters. Our data show considerable beta gamma intensity, so far unobserved in high-resolution gamma-ray spectroscopy, from states at high excitation energy. We also find significant differences with the beta intensity that can be deduced from existing measurements of the beta spectrum. We evaluate the impact of the present data on reactor decay heat using summation calculations. Although the effect is relatively small it helps to reduce the discrepancy between calculations and integral measurements of the photon component for U-235 fission at cooling times in the range 1-100 s. We also use summation calculations to evaluate the impact of present data on reactor antineutrino spectra. We find a significant effect at antineutrino energies in the range of 5 to 9 MeV. In addition, we observe an unexpected strong probability for. emission from neutron unbound states populated in the daughter nucleus. The. branching is compared to Hauser-Feshbach calculations, which allow one to explain the large value for bromine isotopes as due to nuclear structure. However the branching for Rb-94, although much smaller, hints of the need to increase the radiative width gamma by one order of magnitude. This increase in gamma would lead to a similar increase in the calculated (n, gamma) cross section for this very neutron-rich nucleus with a potential impact on r process abundance calculations. |
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Address |
[Valencia, E.; Tain, J. L.; Algora, A.; Agramunt, J.; Estevez, E.; Jordan, M. D.; Rubio, B.] Univ Valencia, CSIC, Inst Fis Corpuscular, Apartado Correos 22085, E-46071 Valencia, Spain, Email: tain@ific.uv.es |
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Thesis |
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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 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:000394662200002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3015 |
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Author |
Molina, F. et al; Rubio, B.; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Gadea, A.; Tain, J.L. |
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Title |
T-z =-1 -> 0 beta decays of Ni-54, Fe-50, Cr-46, and Ti-42 and comparison with mirror (He-3,t) measurements |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
91 |
Issue |
1 |
Pages |
014301 - 19pp |
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Keywords |
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Abstract |
We have studied the beta decay of the T-z = -1, f(7/2) shell nuclei Ni-54, Fe-50, Cr-46, and Ti-42 produced in fragmentation reactions. The proton separation energies in the daughter T-z = 0 nuclei are relatively large (approximate to 4-5 MeV) so studies of the. rays are essential. The experiments were performed at GSI as part of the Stopped-beam campaign with the RISING setup consisting of 15 Euroball Cluster Ge detectors. From the newly obtained high precision beta-decay half-lives, excitation energies, and beta branching ratios, we were able to extract Fermi and Gamow-Teller transition strengths in these beta decays. With these improved results it was possible to compare in detail the Gamow-Teller (GT) transition strengths observed in beta decay including a sensitivity limit with the strengths of the T-z = +1 to T-z = 0 transitions derived from high resolution (He-3,t) reactions on the mirror target nuclei at RCNP, Osaka. The accumulated B(GT) strength obtained from both experiments looks very similar although the charge exchange reaction provides information on a broader energy range. Using the “merged analysis” one can obtain a full picture of the B(GT) over the full Q(beta) range. Looking at the individual transitions some differences are observed, especially for the weak transitions. Their possible origins are discussed. |
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Address |
[Molina, F.; Rubio, B.; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Gadea, A.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: berta.rubio@ific.uv.es |
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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 |
WOS:000347924300002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2087 |
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Author |
n_TOF Collaboration (Massimi, C. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Resonance neutron-capture cross sections of stable magnesium isotopes and their astrophysical implications |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
85 |
Issue |
4 |
Pages |
044615 - 15pp |
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Keywords |
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Abstract |
We have measured the neutron capture cross sections of the stable magnesium isotopes Mg-24,Mg-25,Mg-26 in the energy range of interest to the s process using the neutron time-of-flight facility n_TOF at CERN. Capture events from a natural metal sample and from samples enriched in Mg-25 and Mg-26 were recorded using the total energy method based on (C6H6)-H-2 detectors. Neutron resonance parameters were extracted by a simultaneous resonance shape analysis of the present capture data and existing transmission data on a natural isotopic sample. Maxwellian-averaged capture cross sections for the three isotopes were calculated up to thermal energies of 100 keV and their impact on s-process analyses was investigated. At 30 keV the new values of the stellar cross section for Mg-24, Mg-25, and Mg-26 are 3.8 +/- 0.2 mb, 4.1 +/- 0.6 mb, and 0.14 +/- 0.01 mb, respectively. |
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Address |
[Massimi, C.; Vannini, G.] Univ Bologna, Dipartimento Fis, Bologna, Italy, Email: Cristian.Massimi@bo.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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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:000303069400003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
994 |
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Author |
Mach, H.; Lindroth, A.; Ruchowska, E.; Kvasil, J.; Fogelberg, B.; Gulda, K.; Aas, A.J.; Borge, M.J.G.; Grant, I.S.; Hagebo, E.; Kurcewicz, W.; Martinez, T.; Rubio, B.; Smith, J.F.; Steffensen, K.; Tain, J.L.; Tengblad, O.; Thorsteinsen, T.F. |
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Title |
On the enhanced E1 transitions in the K=3/2 parity doublet band in Ra-223 |
Type |
Journal Article |
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Year |
2016 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
52 |
Issue |
6 |
Pages |
172 - 10pp |
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Keywords |
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Abstract |
We have applied the fast timing beta gamma gamma(t) technique to remeasure lifetimes of selected states in Ra-223 populated in the beta(-) decay of Fr-223. T-1/2 = 587(12) ps and 210(13) ps have been obtained for the 3/2(-) and 5/2(-) states at 50.1 and 79.7 keV, that are more accurate than the previous values of 630(70) ps and 166(55) ps, respectively. Our vertical bar D0 vertical bar value of 0.155(10) e.fm obtained for the K = 3/2 configuration together with the available values of vertical bar D0 vertical bar for the K = 1/2 and K = 5/2 parity doublet bands establish the configuration dependence of vertical bar D0 vertical bar at low spins in this nucleus. Results of theoretical calculations performed for Ra-223, using the quasiparticle-phonon model (QPM) with inclusion of the Coriolis coupling, reasonably well reproduce octupole correlations in this nucleus. |
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Address |
[Mach, H.; Ruchowska, E.; Gulda, K.] Natl Ctr Nucl Res, BP1,Hoza 69, PL-00681 Warsaw, Poland, Email: kurcewic@mimuw.edu.pl |
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Corporate Author |
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Thesis |
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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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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000378999800008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2749 |
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Author |
Tain, J.L. et al; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M.D. |
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Title |
Enhanced gamma-Ray Emission from Neutron Unbound States Populated in beta Decay |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
115 |
Issue |
6 |
Pages |
062502 - 5pp |
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Keywords |
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Abstract |
Total absorption spectroscopy is used to investigate the beta-decay intensity to states above the neutron separation energy followed by gamma-ray emission in Br-87,Br-88 and Rb-94. Accurate results are obtained thanks to a careful control of systematic errors. An unexpectedly large. intensity is observed in all three cases extending well beyond the excitation energy region where neutron penetration is hindered by low neutron energy. The gamma branching as a function of excitation energy is compared to Hauser-Feshbach model calculations. For Br-87 and Br-88 the gamma branching reaches 57% and 20%, respectively, and could be explained as a nuclear structure effect. Some of the states populated in the daughter can only decay through the emission of a large orbital angular momentum neutron with a strongly reduced barrier penetrability. In the case of neutron-rich Rb-94 the observed 4.5% branching is much larger than the calculations performed with standard nuclear statistical model parameters, even after proper correction for fluctuation effects on individual transition widths. The difference can be reconciled by introducing an enhancement of 1 order of magnitude in the photon strength to neutron strength ratio. An increase in the photon strength function of such magnitude for very neutron-rich nuclei, if it proves to be correct, leads to a similar increase in the (n, gamma) cross section that would have an impact on r process abundance calculations. |
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Address |
[Tain, J. L.; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M. D.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: tain@ific.uv.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 |
0031-9007 |
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:000359059100002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2319 |
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| Permanent link to this record |
