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Carroll RJ, Page RD, Joss DT, Uusitalo J, Darby IG, Andgren K, Cederwall B, Eeckhaudt S, Grahn T, Gray-Jones C, Greenlees PT, Hadinia B, Jones PM, Julin R, Juutinen S, Leino M, Leppänen AP, Nyman M, O'Donnell D, Pakarinen J, Rahkila P, Sandzelius M, Sarén J, Scholey C, Seweryniak D, Simpson J. Blurring the boundaries: decays of multiparticle isomers at the proton drip line. Phys Rev Lett 2014; 112:092501. [PMID: 24655248 DOI: 10.1103/physrevlett.112.092501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Indexed: 06/03/2023]
Abstract
A multiparticle spin-trap isomer has been discovered in the proton-unbound nucleus (73)(158)Ta85 . The isomer mainly decays by γ-ray emission with a half-life of 6.1(1) μs. Analysis of the γ-ray data shows that the isomer lies 2668 keV above the known 9+ state and has a spin 10ℏ higher and negative parity. This 19- isomer also has an 8644(11) keV, 1.4(2)% α-decay branch that populates the 9+ state in (154)Lu. No proton-decay branch from the isomer was identified, despite the isomer being unbound to proton emission by 3261(14) keV. This remarkable stability against proton emission is compared with theoretical predictions, and the implications for the extent of observable nuclides are considered.
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Affiliation(s)
- R J Carroll
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - R D Page
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - D T Joss
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - J Uusitalo
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - I G Darby
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - K Andgren
- Department of Physics, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - B Cederwall
- Department of Physics, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - S Eeckhaudt
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - T Grahn
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - C Gray-Jones
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - P T Greenlees
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - B Hadinia
- Department of Physics, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - P M Jones
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - R Julin
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - S Juutinen
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - M Leino
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - A-P Leppänen
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - M Nyman
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - D O'Donnell
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom and STFC, Daresbury Laboratory, Daresbury, Warrington WA4 4AD, United Kingdom
| | - J Pakarinen
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - P Rahkila
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - M Sandzelius
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - J Sarén
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - C Scholey
- Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - D Seweryniak
- Argonne National Laboratory, Physics Division, Argonne, Illinois 60439, USA
| | - J Simpson
- STFC, Daresbury Laboratory, Daresbury, Warrington WA4 4AD, United Kingdom
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Ketelhut S, Greenlees PT, Ackermann D, Antalic S, Clément E, Darby IG, Dorvaux O, Drouart A, Eeckhaudt S, Gall BJP, Görgen A, Grahn T, Gray-Jones C, Hauschild K, Herzberg RD, Hessberger FP, Jakobsson U, Jones GD, Jones P, Julin R, Juutinen S, Khoo TL, Korten W, Leino M, Leppänen AP, Ljungvall J, Moon S, Nyman M, Obertelli A, Pakarinen J, Parr E, Papadakis P, Peura P, Piot J, Pritchard A, Rahkila P, Rostron D, Ruotsalainen P, Sandzelius M, Sarén J, Scholey C, Sorri J, Steer A, Sulignano B, Theisen C, Uusitalo J, Venhart M, Zielinska M, Bender M, Heenen PH. Gamma-ray spectroscopy at the limits: first observation of rotational bands in 255Lr. Phys Rev Lett 2009; 102:212501. [PMID: 19519098 DOI: 10.1103/physrevlett.102.212501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Indexed: 05/27/2023]
Abstract
The rotational band structure of 255Lr has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, 255Lr is the heaviest nucleus to be studied in this manner. One rotational band has been unambiguously observed and strong evidence for a second rotational structure was found. The structures are tentatively assigned to be based on the 1/2-[521] and 7/2-[514] Nilsson states, consistent with assignments from recently obtained alpha decay data. The experimental rotational band dynamic moment of inertia is used to test self-consistent mean-field calculations using the Skyrme SLy4 interaction and a density-dependent pairing force.
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Affiliation(s)
- S Ketelhut
- Department of Physics, University of Jyväskylä, FIN-40014 Jyväskylä, Finland.
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Herzberg RD, Greenlees PT, Butler PA, Jones GD, Venhart M, Darby IG, Eeckhaudt S, Eskola K, Grahn T, Gray-Jones C, Hessberger FP, Jones P, Julin R, Juutinen S, Ketelhut S, Korten W, Leino M, Leppänen AP, Moon S, Nyman M, Page RD, Pakarinen J, Pritchard A, Rahkila P, Sarén J, Scholey C, Steer A, Sun Y, Theisen C, Uusitalo J. Nuclear isomers in superheavy elements as stepping stones towards the island of stability. Nature 2006; 442:896-9. [PMID: 16929293 DOI: 10.1038/nature05069] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Accepted: 07/11/2006] [Indexed: 11/09/2022]
Abstract
A long-standing prediction of nuclear models is the emergence of a region of long-lived, or even stable, superheavy elements beyond the actinides. These nuclei owe their enhanced stability to closed shells in the structure of both protons and neutrons. However, theoretical approaches to date do not yield consistent predictions of the precise limits of the 'island of stability'; experimental studies are therefore crucial. The bulk of experimental effort so far has been focused on the direct creation of superheavy elements in heavy ion fusion reactions, leading to the production of elements up to proton number Z = 118 (refs 4, 5). Recently, it has become possible to make detailed spectroscopic studies of nuclei beyond fermium (Z = 100), with the aim of understanding the underlying single-particle structure of superheavy elements. Here we report such a study of the nobelium isotope 254No, with 102 protons and 152 neutrons--the heaviest nucleus studied in this manner to date. We find three excited structures, two of which are isomeric (metastable). One of these structures is firmly assigned to a two-proton excitation. These states are highly significant as their location is sensitive to single-particle levels above the gap in shell energies predicted at Z = 114, and thus provide a microscopic benchmark for nuclear models of the superheavy elements.
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Affiliation(s)
- R-D Herzberg
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK.
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