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Author (down) Yokoyama, R. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tolosa-Delgado, A. doi  openurl
  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 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:000486641000001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4145  
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Author (down) Yokoyama, R. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tolosa-Delgado, A. doi  openurl
  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 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:001159167500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5939  
Permanent link to this record
 

 
Author (down) Xu, Z.Y. et al; Algora, A.; Morales, A.I. url  doi
openurl 
  Title Beta-delayed neutron spectroscopy of 133In Type Journal Article
  Year 2023 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 108 Issue 1 Pages 014314 - 9pp  
  Keywords  
  Abstract The decay properties of 133In were studied in detail at the ISOLDE Decay Station. The implementation of the Resonance Ionization Laser Ion Source allowed separate measurements of its 9/2+ ground state (133gIn) and 1/2- isomer (133mIn). With the use of & beta;-delayed neutron and & gamma; spectroscopy, the decay strengths above the neutron separation energy were quantified in this neutron-rich nucleus for the first time. The allowed Gamow-Teller transition 9/2+ & RARR; 7/2+ was located at 5.93 MeV in the 133gIn decay with a log ft = 4.7(1). In addition, several neutron-unbound states were populated at lower excitation energies by the first-forbidden decays of 133g,mIn. We assigned spins and parities to those neutron-unbound states based on the & beta;-decay selection rules, the log ft values, and systematics.  
  Address [Xu, Z. Y.; Madurga, M.; Grzywacz, R.; King, T. T.; Halverson, C.; Heideman, J.; Singh, M.; Yokoyama, R.] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 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 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001062056700002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5757  
Permanent link to this record
 

 
Author (down) Xu, Z.Y. et al; Algora, A.; Morales, A.I. url  doi
openurl 
  Title 133In: A Rosetta Stone for Decays of r-Process Nuclei Type Journal Article
  Year 2023 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 131 Issue 2 Pages 022501 - 6pp  
  Keywords  
  Abstract The beta decays from both the ground state and a long-lived isomer of In-133 were studied at the ISOLDE Decay Station (IDS). With a hybrid detection system sensitive to beta,gamma, and neutron spectroscopy, the comparative partial half-lives (log ft) have been measured for all their dominant beta-decay channels for the first time, including a low-energy Gamow-Teller transition and several first-forbidden (FF) transitions. Uniquely for such a heavy neutron-rich nucleus, their beta decays selectively populate only a few isolated neutron unbound states in Sn-133. Precise energy and branching-ratio measurements of those resonances allow us to benchmark beta-decay theories at an unprecedented level in this region of the nuclear chart. The results show good agreement with the newly developed large-scale shell model (LSSM) calculations. The experimental findings establish an archetype for the beta decay of neutron-rich nuclei southeast of Sn-132 and will serve as a guide for future theoretical development aiming to describe accurately the key beta decays in the rapid-neutron capture (r-) process.  
  Address [Xu, Z. Y.; Madurga, M.; Grzywacz, R.; King, T. T.; Halverson, C.; Heideman, J.; Singh, M.; Yokoyama, R.] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 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:001145547400003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5921  
Permanent link to this record
 

 
Author (down) Wu, J. et al; Algora, A.; Agramunt, J.; Morales, A.I.; Orrigo, S.E.A.; Tain, J.L.; Tarifeño-Saldivia, A.; Tolosa-Delgado, A. doi  openurl
  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  
  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  
  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:000906391600002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5452  
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Author (down) Watanabe, H.; Watanabe, Y.X.; Hirayama, Y.; Andreyev, A.N.; Hashimoto, T.; Kondev, F.G.; Lane, G.J.; Litvinov, Y.A.; Liu, J.J.; Miyatake, H.; Moon, J.Y.; Morales, A.I.; Mukai, M.; Nishimura, S.; Niwase, T.; Rosenbusch, M.; Schury, P.; Shi, Y.; Wada, M.; Walker, P.M. doi  openurl
  Title Beta decay of the axially asymmetric ground state of Re-192 Type Journal Article
  Year 2021 Publication Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 814 Issue Pages 136088 - 6pp  
  Keywords Re-192; beta decay; Axial asymmetry; Shape transition  
  Abstract The beta decay of Re-192(75)117, which lies near the boundary between the regions of predicted prolate and oblate deformations, has been investigated using the KEK Isotope Separation System (KISS) in RIKEN Nishina Center. This is the first case in which a low-energy beam of rhenium isotope has been successfully extracted from an argon gas-stopping cell using a laser-ionization technique, following production via multi-nucleon transfer between heavy ions. The ground state of Re-192 has been assigned J(pi) = (0(-)) based on the observed beta feedings and deduced logf t values towards the 0(+) and 2(+) states in Os-192, which is known as a typical gamma-soft nucleus. The shape transition from axial symmetry to axial asymmetry in the Re isotopes is discussed from the viewpoint of single-particle structure using the nuclear Skyrme-Hartree-Fock model.  
  Address [Watanabe, H.] Beihang Univ, Sch Phys, Beijing 100191, Peoples R China, Email: hiroshi@ribf.riken.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:000621722300008 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4747  
Permanent link to this record
 

 
Author (down) Vitez-Sveiczer, A. et al; Algora, A.; Morales, A.I.; Rubio, B.; Agramunt, J.; Guadilla, V.; Montaner-Piza, A.; Orrigo, S.E.A. doi  openurl
  Title The beta-decay of Kr-70 into Br-70: Restoration of the pseudo-SU(4) symmetry Type Journal Article
  Year 2022 Publication Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 830 Issue Pages 137123 - 8pp  
  Keywords Beta decay of Kr-70; pn pairing; GT strength distribution; Pseudo-SU(4) symmetry; QRPA calculations  
  Abstract The beta-decay of the even-even nucleus Kr-70 with Z=N+2, has been investigated at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center using the BigRIPS fragment separator, the ZeroDegree Spectrometer, the WAS3ABI implantation station and the EURICA HPGe cluster array. Fifteen gamma-rays associated with the beta-decay of( 70)Kr into Br-70 have been identified for the first time, defining ten populated states below E-exc=3300 keV. The half-life of Kr-70 was derived with increased precision and found to be t(1/2)=45.19 +/- 0.14 ms. The beta-delayed proton emission probability has also been determined as epsilon(p)=0.545(23)%. An increase in the beta-strength to the yrast 1(+) state in comparison with the heaviest Z=N+2 system studied so far (Ge-62 decay) is observed that may indicate increased np correlations in the T=0 channel. The beta-decay strength deduced from the results is interpreted in terms of the proton-neutron quasiparticle random-phase approximation (pnQRPA) and also with a schematic model that includes isoscalar and isovector pairing in addition to quadrupole deformation. The application of this last model indicates an approximate realization of pseudo-SU(4) symmetry in this system.  
  Address [Vitez-Sveiczer, A.; Algora, A.; Morales, A., I; Rubio, B.; Agramunt, J.; Guadilla, V; Montaner-Piza, A.; Orrigo, S. E. A.; Gelletly, W.] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, Spain, Email: algora@ific.uv.es;  
  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:000832707200002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5316  
Permanent link to this record
 

 
Author (down) Saha, S.; Arici, T.; Gerl, J.; Gorska, M.; Pietralla, N.; Davinson, T.; Morales, A.I.; Podolyak, Z. doi  openurl
  Title On the 6-detection efficiency of a combined Si and plastic stack detector for DESPEC Type Journal Article
  Year 2020 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A  
  Volume 975 Issue Pages 164196 - 8pp  
  Keywords  
  Abstract A Geant4 simulation has been carried out in order to determine the beta-detection efficiency of a rare isotope beam implantation setup, for decay spectroscopy experiments, comprising a number of Double Sided Silicon Strip Detectors (DSSSDs) and two plastic scintillation detectors placed upstream and downstream. The absolute efficiency for the emitted beta-particle detection from radioactive fragments implanted in the DSSSDs using fast-timing plastic-scintillator detector, is calculated. The detection efficiency of the setup has been studied with two different distances between the Si layers and plastics. The requirement for the thickness of the Si detector layers and its implication on the beta-detection efficiency has been investigated for 1 mm and 300 µm thickness of Si layers. The combined efficiency of DSSSD and plastic detectors were also simulated for two different thicknesses of the DSSSD.  
  Address [Saha, S.; Arici, T.; Gerl, J.; Gorska, M.] GSI Helmholtzzentrum Schwerionenforsch, Planckstr 1, D-64291 Darmstadt, Germany, Email: Sudipta_Saha@uml.edu  
  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 0168-9002 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000539967000003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4427  
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Author (down) Phong, V.H. et al; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Morales, A.I.; Tain, J.L.; Tarifeño-Saldivia, A.; Tolosa-Delgado, A. doi  openurl
  Title Observation of a μs isomer in In-134(49)85: Proton-neutron coupling “southeast” of Sn-132(50)82 Type Journal Article
  Year 2019 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 100 Issue 1 Pages 011302 - 6pp  
  Keywords  
  Abstract We report on the observation of a microsecond isomeric state in the single-proton-hole, three-neutron-particle nucleus In-134. The nuclei of interest were produced by in-flight fission of a U-238 beam at the Radioactive Isotope Beam Factory at RIKEN. The isomer depopulates through a gamma ray of energy 56.7(1) keV and with a half-life of T-1/2 = 3.5(4) μs. Based on the comparison with shell-model calculations, we interpret the isomer as the I-pi = 5(-) member of the pi 0g(9/2)(-1) circle times nu 1f(7/2)(3) multiplet, decaying to the I-pi = 7(-) ground state with a reduced-transition probability of B(E2; 5(-) -> 7(-)) = 0.53(6) W.u. Observation of this isomer, and lack of evidence in the current work for a I-pi = 5(-) isomer decay in In-132, provides a benchmark of the proton-neutron interaction in the region of the nuclear chart “southeast” of Sn-132, where experimental information on excited states is sparse.  
  Address [Phong, V. H.; Lorusso, G.; Liu, J.; Matsui, K.; Nishimura, S.; Ahn, D. S.; Baba, H.; Go, S.; Isobe, T.; Kiss, G.; Kubono, S.; Sakurai, H.; Shimizu, Y.; Sumikama, T.; Suzuki, H.; Takeda, H.] RIKEN, RIKEN Nishina Ctr, 2-1 Hirosawa, Wako, Saitama 3510198, Japan, Email: giuseppe.lorusso@npl.co.uk  
  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:000477895400001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4080  
Permanent link to this record
 

 
Author (down) Phong, V.H. et al; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tain, J.L.; Tarifeño-Saldivia, A.; Tolosa-Delgado, A. doi  openurl
  Title Beta-Delayed One and Two Neutron Emission Probabilities South-East of Sn-132 and the Odd-Even Systematics in r-Process Nuclide Abundances Type Journal Article
  Year 2022 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 129 Issue 18 Pages 172701 - 7pp  
  Keywords  
  Abstract The beta-delayed one- and two-neutron emission probabilities (P-1n and P-2n) of 20 neutron-rich nuclei with N >= 82 have been measured at the RIBF facility of the RIKEN Nishina Center. P-1n of Ag-130;131, Cd-133;134, In-135;136, and (138;13)9Sn were determined for the first time, and stringent upper limits were placed on P-2n for nearly all cases. beta-delayed two-neutron emission (beta 2n) was unambiguously identified in Cd-133 and In-135;136, and their P-2n were measured. Weak beta 2n was also detected from Sn-137;138. Our results highlight the effect of the N = 82 and Z = 50 shell closures on beta-delayed neutron emission probability and provide stringent benchmarks for newly developed macroscopic-microscopic and self-consistent global models with the inclusion of a statistical treatment of neutron and. emission. The impact of our measurements on r-process nucleosynthesis was studied in a neutron star merger scenario. Our P-1n and P-2n have a direct impact on the  
  Address [Phong, V. H.; Nishimura, S.; Lorusso, G.; Liu, J.; Nishimura, N.; Ahn, D. S.; Baba, H.; Fukuda, N.; Go, S.; Ha, J.; Isobe, T.; Kiss, G. G.; Kubono, S.; Matsui, K.; Sakurai, H.; Shimizu, Y.; Sumikama, T.; Suzuki, H.; Takeda, H.] RIKEN, Nishina Ctr, Wako, Saitama 3510198, Japan, Email: phong@ribf.riken.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 0031-9007 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000910940600006 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5458  
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