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Author |
Watanabe, H. et al; Montaner-Piza, A. |
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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 |
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Year |
2013 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
111 |
Issue |
15 |
Pages |
152501 - 5pp |
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Keywords |
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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. |
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Address |
[Watanabe, H.] Beihang Univ, Int Res Ctr Nuclei & Particles Cosmos, Beijing 100191, Peoples R China, Email: hiroshi@ribf.riken.jp |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
0031-9007 |
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Notes |
WOS:000325372500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1605 |
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Author |
Taprogge, J. et al; Gadea, A.; Montaner-Piza, A. |
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Title |
1p(3/2) Proton-Hole State in Sn-132 and the Shell Structure Along N=82 |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
112 |
Issue |
13 |
Pages |
132501 - 6pp |
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Keywords |
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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. |
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Address |
[Taprogge, J.; Jungclaus, A.] CSIC, Inst Estruct Mat, E-28006 Madrid, Spain, Email: andrea.jungclaus@csic.es |
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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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ISSN |
0031-9007 |
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Conference |
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Notes |
WOS:000334336600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1759 |
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Author |
Watanabe, H. et al; Montaner-Piza, A. |
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Title |
Monopole-Driven Shell Evolution below the Doubly Magic Nucleus Sn-132 Explored with the Long-Lived Isomer in Pd-126 |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
113 |
Issue |
4 |
Pages |
042502 - 6pp |
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Keywords |
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Abstract |
A new isomer with a half-life of 23.0(8) ms has been identified at 2406 keV in Pd-126 and is proposed to have a spin and parity of 10(+) with a maximally aligned configuration comprising two neutron holes in the 1h(11/2) orbit. In addition to an internal-decay branch through a hindered electric octupole transition, beta decay from the long-lived isomer was observed to populate excited states at high spins in Ag-126. The smaller energy difference between the 10(+) and 7(-) isomers in Pd-126 than in the heavier N = 80 isotones can be interpreted as being ascribed to the monopole shift of the 1h(11/2) neutron orbit. The effects of the monopole interaction on the evolution of single-neutron energies below Sn-132 are discussed in terms of the central and tensor forces. |
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Address |
[Watanabe, H.] Beihang Univ, Sch Phys & Nucl Energy Engn, IRCNPC, Beijing 100191, Peoples R China, Email: hiroshi@ribf.riken.jp |
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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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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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Expedition |
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Conference |
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Notes |
WOS:000341261100004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1910 |
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Permanent link to this record |
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Author |
Simpson, G.S. et al; Montaner-Piza, A. |
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Title |
Yrast 6(+) Seniority Isomers of Sn-136,Sn-138 |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
113 |
Issue |
13 |
Pages |
132502 - 6pp |
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Keywords |
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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. |
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Address |
[Simpson, G. S.] Univ West Scotland, Sch Engn, Paisley PA1 2BE, Renfrew, Scotland |
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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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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:000342666500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1957 |
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Permanent link to this record |
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Author |
Lorusso, G. et al; Montaner-Piza, A. |
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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 |
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Year |
2015 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
114 |
Issue |
19 |
Pages |
192501 - 7pp |
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Keywords |
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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. |
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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 |
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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:000354347300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2224 |
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Permanent link to this record |