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Author Guadilla, V. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Orrigo, S.E.A.; Rubio, B.; Valencia, E. url  doi
openurl 
  Title (up) Determination of beta-decay ground state feeding of nuclei of importance for reactor applications Type Journal Article
  Year 2020 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 102 Issue 6 Pages 064304 - 12pp  
  Keywords  
  Abstract In beta-decay studies the determination of the decay probability to the ground state (g.s.) of the daughter nucleus often suffers from large systematic errors. The difficulty of the measurement is related to the absence of associated delayed gamma-ray emission. In this work we revisit the 4 pi gamma – beta method proposed by Greenwood and collaborators in the 1990s, which has the potential to overcome some of the experimental difficulties. Our interest is driven by the need to determine accurately the beta-intensity distributions of fission products that contribute significantly to the reactor decay heat and to the antineutrinos emitted by reactors. A number of such decays have large g.s. branches. The method is relevant for nuclear structure studies as well. Pertinent formulas are revised and extended to the special case of beta-delayed neutron emitters, and the robustness of the method is demonstrated with synthetic data. We apply it to a number of measured decays that serve as test cases and discuss the features of the method. Finally, we obtain g.s. feeding intensities with reduced uncertainty for four relevant decays that will allow future improvements in antineutrino spectrum and decay heat calculations using the summation method.  
  Address [Guadilla, V; Tain, J. L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Orrigo, S. E. A.; Rubio, B.; Valencia, E.] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, Spain  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000595153500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4626  
Permanent link to this record
 

 
Author Wimmer, K. et al; Algora, A.; Rubio, B. url  doi
openurl 
  Title (up) Discovery of Br-68 in secondary reactions of radioactive beams Type Journal Article
  Year 2019 Publication Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 795 Issue Pages 266-270  
  Keywords Radioactive beams; New isotope; Direct reaction  
  Abstract The proton-rich isotope Br-68 was discovered in secondary fragmentation reactions of fast radioactive beams. Proton-rich secondary beams of (70,71,72) Kr and Br-70, produced at the RIKEN Nishina Center and identified by the BigRIPS fragment separator, impinged on a secondary Be-9 target. Unambiguous particle identification behind the secondary target was achieved with the ZeroDegree spectrometer. Based on the expected direct production cross sections from neighboring isotopes, the lifetime of the ground or long-lived isomeric state of Br-68 was estimated. The results suggest that secondary fragmentation reactions, where relatively few nucleons are removed from the projectile, offer an alternative way to search for new isotopes, as these reactions populate preferentially low-lying states.  
  Address [Wimmer, K.; Ando, T.; Koyama, S.; Nagamine, S.; Niikura, M.; Saito, Ty; Sakurai, H.; Taniuchi, R.] Univ Tokyo, Dept Phys, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1130033, Japan, Email: wimmer@phys.s.u-tokyo.ac.jp  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0370-2693 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000477924000037 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4100  
Permanent link to this record
 

 
Author Tain, J.L. et al; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M.D. url  doi
openurl 
  Title (up) Enhanced gamma-Ray Emission from Neutron Unbound States Populated in beta Decay Type Journal Article
  Year 2015 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 115 Issue 6 Pages 062502 - 5pp  
  Keywords  
  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.  
  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  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9007 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000359059100002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2319  
Permanent link to this record
 

 
Author Liddick, S.N.; Spyrou, A.; Crider, B.P.; Naqvi, F.; Larsen, A.C.; Guttormsen, M.; Mumpower, M.; Surman, R.; Perdikakis, G.; Bleuel, D.L.; Couture, A.; Campo, L.C.; Dombos, A.C.; Lewis, R.; Mosby, S.; Nikas, S.; Prokop, C.J.; Renstrom, T.; Rubio, B.; Siem, S.; Quinn, S.J. doi  openurl
  Title (up) Experimental Neutron Capture Rate Constraint Far from Stability Type Journal Article
  Year 2016 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 116 Issue 24 Pages 242502 - 6pp  
  Keywords  
  Abstract Nuclear reactions where an exotic nucleus captures a neutron are critical for a wide variety of applications, from energy production and national security, to astrophysical processes, and nucleosynthesis. Neutron capture rates are well constrained near stable isotopes where experimental data are available; however, moving far from the valley of stability, uncertainties grow by orders of magnitude. This is due to the complete lack of experimental constraints, as the direct measurement of a neutron-capture reaction on a short-lived nucleus is extremely challenging. Here, we report on the first experimental extraction of a neutron capture reaction rate on Ni-69, a nucleus that is five neutrons away from the last stable isotope of Ni. The implications of this measurement on nucleosynthesis around mass 70 are discussed, and the impact of similar future measurements on the understanding of the origin of the heavy elements in the cosmos is presented.  
  Address [Liddick, S. N.; Spyrou, A.; Crider, B. P.; Naqvi, F.; Perdikakis, G.; Dombos, A. C.; Lewis, R.; Prokop, C. J.; Quinn, S. J.] Michigan State Univ, Natl Supercond Cyclotron Lab, E Lansing, MI 48824 USA  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9007 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000378058700003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2735  
Permanent link to this record
 

 
Author Fujita, H. et al; Algora, A.; Estevez-Aguado, E.; Molina, F.; Rubio, B. doi  openurl
  Title (up) Experimental study of Gamow-Teller transitions via the high-energy-resolution O-18(He-3, t)F-18 reaction: Identification of the low-energy “super” -Gamow-Teller state Type Journal Article
  Year 2019 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 100 Issue 3 Pages 034618 - 13pp  
  Keywords  
  Abstract Using the high-resolution O-18(He-3, t)F-18 reaction at 0 degrees and at 140 MeV/nucleon, Gamow-Teller (GT) transitions were studied. A high energy resolution of 31 keV was achieved by applying dispersion matching techniques. The main part of the observed GT transition strength is concentrated in the transition to the F-18 ground state (g.s.). The absolute values of the reduced GT transition strengths, B(GT), were derived up to E-x = 12 MeV assuming proportionality between the B(GT) values and the reaction cross sections at 0 degrees. The B(GT) value obtained from the beta decay of F-18 (g.s.) -> O-18 (g.s.) was used to determine the proportionality constant. A total B(GT) of 4.06(5) was found and 76(1)% of the strength is concentrated to the ground state of F-18. The obtained B(GT) values were compared with those from the O-18(p, n) F-18 reaction and the mirror symmetric beta(+) decay of Ne-18 -> F-18. The candidates for 1(+) states with isospin T = 1 were identified by comparison with the O-18(p, p') data. The results of shell-model and quasiparticle-random-phase approximation calculations suggest constructive contributions of various configurations to the F-18 ground state, suggesting that this state is the low-energy super GT state.  
  Address [Fujita, H.; Fujita, Y.; Adachi, T.; Hatanaka, K.; Hirota, K.; Ishikawa, D.; Matsubara, H.; Okamura, H.; Ong, H. J.; Susoy, G.; Suzuki, T.; Tamii, A.; Zenihiro, J.] Osaka Univ, Res Ctr Nucl Phys, Ibaraki, Osaka 5670047, Japan, Email: hfujita@rcnp.osaka-u.ac.jp  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000488259800004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4165  
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