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Haettner E, Ackermann D, Audi G, Blaum K, Block M, Eliseev S, Fleckenstein T, Herfurth F, Hessberger FP, Hofmann S, Ketelaer J, Ketter J, Kluge HJ, Marx G, Mazzocco M, Novikov YN, Plass WR, Rahaman S, Rauscher T, Rodríguez D, Schatz H, Scheidenberger C, Schweikhard L, Sun B, Thirolf PG, Vorobjev G, Wang M, Weber C. Mass measurements of very neutron-deficient Mo and Tc isotopes and their impact on rp process nucleosynthesis. Phys Rev Lett 2011; 106:122501. [PMID: 21517310 DOI: 10.1103/physrevlett.106.122501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Indexed: 05/30/2023]
Abstract
The masses of ten proton-rich nuclides, including the N=Z+1 nuclides ⁸⁵Mo and ⁸⁷Tc, were measured with the Penning trap mass spectrometer SHIPTRAP. Compared to the Atomic Mass Evaluation 2003 a systematic shift of the mass surface by up to 1.6 MeV is observed causing significant abundance changes of the ashes of astrophysical x-ray bursts. Surprisingly low α separation energies for neutron-deficient Mo and Tc are found, making the formation of a ZrNb cycle in the rp process possible. Such a cycle would impose an upper temperature limit for the synthesis of elements beyond Nb in the rp process.
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Affiliation(s)
- E Haettner
- II. Physikalisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany.
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Düllmann CE, Schädel M, Yakushev A, Türler A, Eberhardt K, Kratz JV, Ackermann D, Andersson LL, Block M, Brüchle W, Dvorak J, Essel HG, Ellison PA, Even J, Gates JM, Gorshkov A, Graeger R, Gregorich KE, Hartmann W, Herzberg RD, Hessberger FP, Hild D, Hübner A, Jäger E, Khuyagbaatar J, Kindler B, Krier J, Kurz N, Lahiri S, Liebe D, Lommel B, Maiti M, Nitsche H, Omtvedt JP, Parr E, Rudolph D, Runke J, Schausten B, Schimpf E, Semchenkov A, Steiner J, Thörle-Pospiech P, Uusitalo J, Wegrzecki M, Wiehl N. Production and decay of element 114: high cross sections and the new nucleus 277Hs. Phys Rev Lett 2010; 104:252701. [PMID: 20867370 DOI: 10.1103/physrevlett.104.252701] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Indexed: 05/29/2023]
Abstract
The fusion-evaporation reaction 244Pu(48Ca,3-4n){288,289}114 was studied at the new gas-filled recoil separator TASCA. Thirteen correlated decay chains were observed and assigned to the production and decay of {288,289}114. At a compound nucleus excitation energy of E{*}=39.8-43.9 MeV, the 4n evaporation channel cross section was 9.8{-3.1}{+3.9} pb. At E^{*}=36.1-39.5 MeV, that of the 3n evaporation channel was 8.0{-4.5}{+7.4} pb. In one of the 3n evaporation channel decay chains, a previously unobserved α branch in 281Ds was observed (probability to be of random origin from background: 0.1%). This α decay populated the new nucleus 277Hs, which decayed by spontaneous fission after a lifetime of 4.5 ms.
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Affiliation(s)
- Ch E Düllmann
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany.
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Block M, Ackermann D, Blaum K, Droese C, Dworschak M, Eliseev S, Fleckenstein T, Haettner E, Herfurth F, Hessberger FP, Hofmann S, Ketelaer J, Ketter J, Kluge HJ, Marx G, Mazzocco M, Novikov YN, Plass WR, Popeko A, Rahaman S, Rodríguez D, Scheidenberger C, Schweikhard L, Thirolf PG, Vorobyev GK, Weber C. Direct mass measurements above uranium bridge the gap to the island of stability. Nature 2010; 463:785-8. [DOI: 10.1038/nature08774] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 12/17/2009] [Indexed: 11/09/2022]
Affiliation(s)
- M Block
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany.
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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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Rauth C, Ackermann D, Blaum K, Block M, Chaudhuri A, Di Z, Eliseev S, Ferrer R, Habs D, Herfurth F, Hessberger FP, Hofmann S, Kluge HJ, Maero G, Martín A, Marx G, Mukherjee M, Neumayr JB, Plass WR, Rahaman S, Rodríguez D, Scheidenberger C, Schweikhard L, Thirolf PG, Vorobjev G, Weber C. First Penning trap mass measurements beyond the proton drip line. Phys Rev Lett 2008; 100:012501. [PMID: 18232754 DOI: 10.1103/physrevlett.100.012501] [Citation(s) in RCA: 2] [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: 10/26/2006] [Revised: 07/19/2007] [Indexed: 05/25/2023]
Abstract
The masses of six neutron-deficient rare holmium and thulium isotopes close to the proton drip line were determined with the SHIPTRAP Penning trap mass spectrometer. For the first time the masses of the proton-unbound isotopes 144,145Ho and 147,148Tm were directly measured. The proton separation energies were derived from the measured mass values and compared to predictions from mass formulas. The new values of the proton separation energies are used to determine the location of the proton drip line for holmium and thulium more accurately.
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Affiliation(s)
- C Rauth
- Gesellschaft für Schwerionenforschung (GSI), Planckstrasse 1, 64291 Darmstadt, Germany
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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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Ghiorso A, Seaborg GT, Organessian YT, Zvara I, Armbruster P, Hessberger FP, Hofmann S, Leino M, Munzenberg G, Reisdorf W, Schmidt KH. Responses on 'Discovery of the transfermium elements' by Lawrence Berkeley Laboratory, California; Joint Institute for Nuclear Research, Dubna; and Gesellschaft fur Schwerionenforschung, Darmstadt followed by reply to responses by the Transfermium Working Group. PURE APPL CHEM 1993. [DOI: 10.1351/pac199365081815] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
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Armbruster P, Agarwal YK, Brüchle W, Brügger M, Dufour JP, Gaggeler H, Hessberger FP, Hofmann S, Lemmertz P, Münzenberg G, Poppensieker K, Reisdorf W, Schadel M, Schmidt K, Schneider JH, Schneider WF, Sümmerer K, Vermeulen D, Wirth AG, Ghiorso A, Gregorich KE, Lee D, Leino M, Moody KJ, Seaborg GT, Welch RB, Wilmarth P, Yashita S, Frink C, Greulich N, Herrmann G, Hickmann U, Hildebrand N, Kratz JV, Trautman N, Fowler MM, Hoffman DC, Daniels WR, Dornhöfer H. Attempts to produce superheavy elements by fusion of 48Ca with 248Cm in the bombarding energy range of 4.5-5.2 MeV/u. Phys Rev Lett 1985; 54:406-409. [PMID: 10031507 DOI: 10.1103/physrevlett.54.406] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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