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Author Chen, Z.Q. et al; Montaner-Piza, A.
Title Proton Shell Evolution below Sn-132: First Measurement of Low-Lying beta-Emitting Isomers in Ag-123,Ag-325 Type Journal Article
Year 2019 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 122 Issue 21 Pages (down) 212502 - 6pp
Keywords
Abstract The beta-delayed gamma-ray spectroscopy of neutron-rich Ag-123,Ag-325 isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN, and the long-predicted 1/2(-) beta-emitting isomers in Ag-123,Ag-325 are identified for the first time. With the new experimental results, the systematic trend of energy spacing between the lowest 9/2(+) and 1/2(-) levels is extended in Ag isotopes up to N = 78, providing a clear signal for the reduction of the Z = 40 subshell gap in Ag towards N = 82. Shell-model calculations with the state-of-the-art V-MU plus M3Y spin-orbit interaction give a satisfactory description of the low-lying states in Ag-123,Ag-325. The tensor force is found to play a crucial role in the evolution of the size of the Z = 40 subshell gap. The observed inversion of the single-particle levels around Ag-123 can be well interpreted in terms of the monopole shift of the pi 1g(9/2) orbitals mainly caused by the increasing occupation of nu 1h(11/2) orbitals.
Address [Chen, Z. Q.; Li, Z. H.; Hua, H.; Zhang, S. Q.; Jiang, D. X.; Jin, Y.; Li, X. Q.; Lou, J. L.; Li, C. G.; Luo, D. W.; Niu, C. Y.; Wu, J.; Wang, C. G.; Wu, H. Y.; Wang, X.; Wu, C. G.; Xu, C.; Ye, Y. L.] Peking Univ, Sch Phys, Beijing 100871, Peoples R China, Email: zhli@pku.edu.cn;
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:000469334100003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4031
Permanent link to this record
 
 
Author Lorusso, G. et al; Montaner-Piza, A.
Title beta-Decay Half-Lives of 110 Neutron-Rich Nuclei across the N=82 Shell Gap: Implications for the Mechanism and Universality of the Astrophysical r Process Type Journal Article
Year 2015 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 114 Issue 19 Pages (down) 192501 - 7pp
Keywords
Abstract The beta-decay half-lives of 110 neutron-rich isotopes of the elements from 37 Rb to 50 Sn were measured at the Radioactive Isotope Beam Factory. The 40 new half-lives follow robust systematics and highlight the persistence of shell effects. The new data have direct implications for r-process calculations and reinforce the notion that the second (A approximate to 130) and the rare-earth-element (A approximate to 160) abundance peaks may result from the freeze-out of an (n, gamma) reversible arrow (gamma, n) equilibrium. In such an equilibrium, the new half-lives are important factors determining the abundance of rare-earth elements, and allow for a more reliable discussion of the r process universality. It is anticipated that universality may not extend to the elements Sn, Sb, I, and Cs, making the detection of these elements in metal-poor stars of the utmost importance to determine the exact conditions of individual r-process events.
Address [Lorusso, G.; Nishimura, S.; Xu, Z. Y.; Shimizu, Y.; Soederstroem, P. -A.; Watanabe, H.; Browne, F.; Doornenbal, P.; Gey, G.; Taprogge, J.; Vajta, Zs.; Wu, J.; Baba, H.; Fukuda, N.; Inabe, N.; Isobe, T.; Kameda, D.; Kubo, T.; Sakurai, H.; Schury, P.; Suzuki, H.; Takeda, H.] RIKEN, Nishina Ctr, Wako, Saitama 3510198, Japan
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:000354347300001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2224
Permanent link to this record
 
 
Author Goigoux, T. et al; Algora, A.; Guadilla, V.; Montaner-Piza, A.; Morales, A.I.; Orrigo, S.E.A.; Rubio, B.; Gelletly, W.
Title Two-Proton Radioactivity of Kr-67 Type Journal Article
Year 2016 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 117 Issue 16 Pages (down) 162501 - 6pp
Keywords
Abstract In an experiment with the BigRIPS separator at the RIKEN Nishina Center, we observed two-proton (2p) emission from Kr-67. At the same time, no evidence for 2p emission of Ge-59 and Se-63, two other potential candidates for this exotic radioactivity, could be observed. This observation is in line with Q value predictions which pointed to Kr-67 as being the best new candidate among the three for two-proton radioactivity. Kr-67 is only the fourth 2p ground-state emitter to be observed with a half-life of the order of a few milliseconds. The decay energy was determined to be 1690(17) keV, the 2p emission branching ratio is 37(14)%, and the half-life of Kr-67 is 7.4(30) ms.
Address [Goigoux, T.; Ascher, P.; Blank, B.; Gerbaux, M.; Giovinazzo, J.; Grevy, S.; Nieto, T. Kurtukian; Magron, C.] Univ Bordeaux, Ctr Etud Nucl Bordeaux Gradignan, IN2P3, UMR CNRS 5797, Chemin Solarium, F-33175 Gradignan, France
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:000385641900003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2831
Permanent link to this record
 
 
Author Watanabe, H. et al; Montaner-Piza, A.
Title Isomers in Pd-128 and Pd-126: Evidence for a Robust Shell Closure at the Neutron Magic Number 82 in Exotic Palladium Isotopes Type Journal Article
Year 2013 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 111 Issue 15 Pages (down) 152501 - 5pp
Keywords
Abstract The level structures of the very neutron-rich nuclei Pd-128 and Pd-126 have been investigated for the first time. In the r-process waiting-point nucleus Pd-128, a new isomer with a half-life of 5.8(8) μs is proposed to have a spin and parity of 8(+) and is associated with a maximally aligned configuration arising from the g(9/2) proton subshell with seniority v = 2. For Pd-126, two new isomers have been identified with half-lives of 0.33(4) and 0.44(3) μs. The yrast 2(+) energy is much higher in Pd-128 than in Pd-126, while the level sequence below the 8(+) isomer in Pd-128 is similar to that in the N = 82 isotone Cd-130. The electric quadrupole transition that depopulates the 8(+) isomer in Pd-128 is more hindered than the corresponding transition in Cd-130, as expected in the seniority scheme for a semimagic, spherical nucleus. These experimental findings indicate that the shell closure at the neutron number N = 82 is fairly robust in the neutron-rich Pd isotopes.
Address [Watanabe, H.] Beihang Univ, Int Res Ctr Nuclei & Particles Cosmos, Beijing 100191, Peoples R China, Email: hiroshi@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:000325372500001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1605
Permanent link to this record
 
 
Author Vitez-Sveiczer, A. et al; Algora, A.; Morales, A.I.; Rubio, B.; Agramunt, J.; Guadilla, V.; Montaner-Piza, A.; Orrigo, S.E.A.
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 (down) 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 Watanabe, H. et al; Montaner-Piza, A.
Title Impact of shell evolution on Gamow-Teller beta decay from a high-spin long-lived isomer in Ag-127 Type Journal Article
Year 2021 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 823 Issue Pages (down) 136766 - 6pp
Keywords Shell evolution; Gamow-Teller beta decay; Isomer; Ag-127; Radioactive isotope beam
Abstract The change of the shell structure in atomic nuclei, so-called “nuclear shell evolution”, occurs due to changes of major configurations through particle-hole excitations inside one nucleus, as well as due to variation of the number of constituent protons or neutrons. We have investigated how the shell evolution affects Gamow-Teller (GT) transitions that dominate the beta decay in the region below Sn-132 using the newly obtained experimental data on a long-lived isomer in Ag-127. The T-1/2 = 67.5(9) ms isomer has been identified with a spin and parity of (27/2(+)) at an excitation energy of 1942(-20)(+14) keV, and found to decay via an internal transition of an E3 character, which competes with the dominant beta-decay branches towards the high-spin states in Cd-127. The underlying mechanism of a strong GT transition from the Ag-127 isomer is discussed in terms of configuration-dependent optimization of the effective single-particle energies in the framework of a shell-model approach.
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:000719296400003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5041
Permanent link to this record
 
 
Author Simpson, G.S. et al; Montaner-Piza, A.
Title Yrast 6(+) Seniority Isomers of Sn-136,Sn-138 Type Journal Article
Year 2014 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 113 Issue 13 Pages (down) 132502 - 6pp
Keywords
Abstract Delayed gamma-ray cascades, originating from the decay of (6(+)) isomeric states, in the very neutron-rich, semimagic isotopes Sn-136,Sn-138 have been observed following the projectile fission of a U-238 beam at RIBF, RIKEN. The wave functions of these isomeric states are proposed to be predominantly a fully aligned pair of f(7/2) neutrons. Shell-model calculations, performed using a realistic effective interaction, reproduce well the energies of the excited states of these nuclei and the measured transition rates, with the exception of the B(E2; 6(+) -> 4(+)) rate of Sn-136, which deviates from a simple seniority scheme. Empirically reducing the nu f(7/2)(2) orbit matrix elements produces a 4(1)(+) state with almost equal seniority 2 and 4 components, correctly reproducing the experimental B(E2; 6(+) -> 4(+)) rate of Sn-136. These data provide a key benchmark for shell-model interactions far from stability.
Address [Simpson, G. S.] Univ West Scotland, Sch Engn, Paisley PA1 2BE, Renfrew, Scotland
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:000342666500001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1957
Permanent link to this record
 
 
Author Taprogge, J. et al; Gadea, A.; Montaner-Piza, A.
Title 1p(3/2) Proton-Hole State in Sn-132 and the Shell Structure Along N=82 Type Journal Article
Year 2014 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 112 Issue 13 Pages (down) 132501 - 6pp
Keywords
Abstract A low-lying state in In-131(82), the one-proton hole nucleus with respect to double magic Sn-132, was observed by its gamma decay to the I-pi 1/2(-) beta-emitting isomer. We identify the new state at an excitation energy of E-x = 1353 keV, which was populated both in the beta decay of Cd-131(83) and after beta-delayed neutron emission from Cd-132(84), as the previously unknown pi p(3/2) single-hole state with respect to the Sn-132 core. Exploiting this crucial new experimental information, shell-model calculations were performed to study the structure of experimentally inaccessible N = 82 isotones below Sn-132. The results evidence a surprising absence of proton subshell closures along the chain of N = 82 isotones. The consequences of this finding for the evolution of the N = 82 shell gap along the r-process path are discussed.
Address [Taprogge, J.; Jungclaus, A.] CSIC, Inst Estruct Mat, E-28006 Madrid, Spain, Email: andrea.jungclaus@csic.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:000334336600001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1759
Permanent link to this record
 
 
Author Morales, A.I. et al; Algora, A.; Rubio, B.; Orrigo, S.E.A.; Agramunt, J.; Gelletly, W.; Guadilla, V.; Montaner-Piza, A.
Title Simultaneous investigation of the T=1(J(pi)=0(+)) and T=0(J(pi)=9(+)) beta decays in Br-70 Type Journal Article
Year 2017 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 95 Issue 6 Pages (down) 064327 - 11pp
Keywords
Abstract The beta decay of the odd-odd nucleus Br-70 has been investigated with the BigRIPS and EURICA setups at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center. The T = 0(J(pi) = 9(+)) and T = 1(J(pi) = 0(+)) isomers have both been produced in in-flight fragmentation of Kr-78 with ratios of 41.6(8)% and 58.4(8)%, respectively. A half-life of t(1/2) = 2157(-49)(+53) ms has been measured for the J pi = 9(+) isomer from gamma-ray time decay analysis. Based on this result, we provide a new value of the half-life for the J pi = 0(+) ground state of Br-70, t(1/2) = 78.42 +/- 0.51 ms, which is slightly more precise, and in excellent agreement, with the best measurement reported hitherto in the literature. For this decay, we provide the first estimate of the total branching fraction decaying through the 2(1)(+) state in the daughter nucleus Se-70, R(2(1)(+)) = 1.3 +/- 1.1%. We also report four new low-intensity gamma-ray transitions at 661, 1103, 1561, and 1749 keV following the beta decay of the J pi = 9(+) isomer. Based on their coincidence relationships, we tentatively propose two new excited states at 3945 and 4752 keV in 70Se with most probable spins and parities of J(pi) = (6(+)) and (8(+)), respectively. The observed structure is interpreted with the help of shell-model calculations, which predict a complex interplay between oblate and prolate configurations at low excitation energies.
Address [Morales, A. I.; Algora, A.; Rubio, B.; Orrigo, S. E. A.; Agramunt, J.; Gelletly, W.; Guadilla, V.; Montaner-Piza, A.] Univ Valencia, CSIC, IFIC, E-46071 Valencia, Spain, Email: Ana.Morales@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 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000404470900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3184
Permanent link to this record
 
 
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.
Title 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 (down) 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