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Khuyagbaatar J, Yakushev A, Düllmann CE, Ackermann D, Andersson LL, Block M, Brand H, Cox DM, Even J, Forsberg U, Golubev P, Hartmann W, Herzberg RD, Heßberger FP, Hoffmann J, Hübner A, Jäger E, Jeppsson J, Kindler B, Kratz JV, Krier J, Kurz N, Lommel B, Maiti M, Minami S, Mistry AK, Mrosek CM, Pysmenetska I, Rudolph D, Sarmiento LG, Schaffner H, Schädel M, Schausten B, Steiner J, De Heidenreich TT, Uusitalo J, Wegrzecki M, Wiehl N, Yakusheva V. New Short-Lived Isotope ^{221}U and the Mass Surface Near N=126. Phys Rev Lett 2015; 115:242502. [PMID: 26705628 DOI: 10.1103/physrevlett.115.242502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Indexed: 06/05/2023]
Abstract
Two short-lived isotopes ^{221}U and ^{222}U were produced as evaporation residues in the fusion reaction ^{50}Ti+^{176}Yb at the gas-filled recoil separator TASCA. An α decay with an energy of E_{α}=9.31(5) MeV and half-life T_{1/2}=4.7(7) μs was attributed to ^{222}U. The new isotope ^{221}U was identified in α-decay chains starting with E_{α}=9.71(5) MeV and T_{1/2}=0.66(14) μs leading to known daughters. Synthesis and detection of these unstable heavy nuclei and their descendants were achieved thanks to a fast data readout system. The evolution of the N=126 shell closure and its influence on the stability of uranium isotopes are discussed within the framework of α-decay reduced width.
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Affiliation(s)
- J Khuyagbaatar
- Helmholtz Institute Mainz, 55099 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - A Yakushev
- Helmholtz Institute Mainz, 55099 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - Ch E Düllmann
- Helmholtz Institute Mainz, 55099 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
- Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - D Ackermann
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | | | - M Block
- Helmholtz Institute Mainz, 55099 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
- Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - H Brand
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - D M Cox
- University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - J Even
- Helmholtz Institute Mainz, 55099 Mainz, Germany
| | | | | | - W Hartmann
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - R-D Herzberg
- University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - F P Heßberger
- Helmholtz Institute Mainz, 55099 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - J Hoffmann
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - A Hübner
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - E Jäger
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | | | - B Kindler
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - J V Kratz
- Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - J Krier
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - N Kurz
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - B Lommel
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - M Maiti
- Saha Institute of Nuclear Physics, Kolkata 700064, India
| | - S Minami
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - A K Mistry
- University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - Ch M Mrosek
- Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - I Pysmenetska
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | | | | | - H Schaffner
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - M Schädel
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - B Schausten
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - J Steiner
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | | | - J Uusitalo
- University of Jyväskylä, 40351 Jyväskylä, Finland
| | - M Wegrzecki
- The Institute of Electron Technology, 02-668 Warsaw, Poland
| | - N Wiehl
- Helmholtz Institute Mainz, 55099 Mainz, Germany
- Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - V Yakusheva
- Helmholtz Institute Mainz, 55099 Mainz, Germany
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Khuyagbaatar J, Yakushev A, Düllmann CE, Ackermann D, Andersson LL, Asai M, Block M, Boll RA, Brand H, Cox DM, Dasgupta M, Derkx X, Di Nitto A, Eberhardt K, Even J, Evers M, Fahlander C, Forsberg U, Gates JM, Gharibyan N, Golubev P, Gregorich KE, Hamilton JH, Hartmann W, Herzberg RD, Heßberger FP, Hinde DJ, Hoffmann J, Hollinger R, Hübner A, Jäger E, Kindler B, Kratz JV, Krier J, Kurz N, Laatiaoui M, Lahiri S, Lang R, Lommel B, Maiti M, Miernik K, Minami S, Mistry A, Mokry C, Nitsche H, Omtvedt JP, Pang GK, Papadakis P, Renisch D, Roberto J, Rudolph D, Runke J, Rykaczewski KP, Sarmiento LG, Schädel M, Schausten B, Semchenkov A, Shaughnessy DA, Steinegger P, Steiner J, Tereshatov EE, Thörle-Pospiech P, Tinschert K, Torres De Heidenreich T, Trautmann N, Türler A, Uusitalo J, Ward DE, Wegrzecki M, Wiehl N, Van Cleve SM, Yakusheva V. 48Ca+249Bk fusion reaction leading to element Z = 117: long-lived α-decaying 270Db and discovery of 266Lr. Phys Rev Lett 2014; 112:172501. [PMID: 24836239 DOI: 10.1103/physrevlett.112.172501] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Indexed: 06/03/2023]
Abstract
The superheavy element with atomic number Z=117 was produced as an evaporation residue in the (48)Ca+(249)Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope (294)117 and its decay products. A hitherto unknown α-decay branch in (270)Db (Z = 105) was observed, which populated the new isotope (266)Lr (Z = 103). The identification of the long-lived (T(1/2) = 1.0(-0.4)(+1.9) h) α-emitter (270)Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an "island of stability."
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Affiliation(s)
- J Khuyagbaatar
- Helmholtz Institute Mainz, 55099 Mainz, Germany and GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - A Yakushev
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - Ch E Düllmann
- Helmholtz Institute Mainz, 55099 Mainz, Germany and GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany and Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - D Ackermann
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | | | - M Asai
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - M Block
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - R A Boll
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - H Brand
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - D M Cox
- University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - M Dasgupta
- The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - X Derkx
- Helmholtz Institute Mainz, 55099 Mainz, Germany and Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - A Di Nitto
- Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - K Eberhardt
- Helmholtz Institute Mainz, 55099 Mainz, Germany and Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - J Even
- Helmholtz Institute Mainz, 55099 Mainz, Germany
| | - M Evers
- The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | | | | | - J M Gates
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - N Gharibyan
- Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | | | - K E Gregorich
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - J H Hamilton
- Vanderbilt University, Nashville, Tennessee 37235, USA
| | - W Hartmann
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - R-D Herzberg
- University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - F P Heßberger
- Helmholtz Institute Mainz, 55099 Mainz, Germany and GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - D J Hinde
- The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - J Hoffmann
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - R Hollinger
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - A Hübner
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - E Jäger
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - B Kindler
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - J V Kratz
- Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - J Krier
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - N Kurz
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - M Laatiaoui
- Helmholtz Institute Mainz, 55099 Mainz, Germany
| | - S Lahiri
- Saha Institute of Nuclear Physics, Kolkata 700064, India
| | - R Lang
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - B Lommel
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - M Maiti
- Saha Institute of Nuclear Physics, Kolkata 700064, India
| | - K Miernik
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - S Minami
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - A Mistry
- University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - C Mokry
- Helmholtz Institute Mainz, 55099 Mainz, Germany and Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - H Nitsche
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | | | - G K Pang
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - P Papadakis
- University of Liverpool, Liverpool L69 7ZE, United Kingdom and University of Jyväskylä, 40351 Jyväskylä, Finland
| | - D Renisch
- Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - J Roberto
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | | | - J Runke
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - K P Rykaczewski
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | | | - M Schädel
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany and Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - B Schausten
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | | | - D A Shaughnessy
- Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - P Steinegger
- Paul Scherrer Institute, 5232 Villigen, Switzerland and University of Bern, 3012 Bern, Switzerland
| | - J Steiner
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - E E Tereshatov
- Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - P Thörle-Pospiech
- Helmholtz Institute Mainz, 55099 Mainz, Germany and Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - K Tinschert
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | | | - N Trautmann
- Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - A Türler
- Paul Scherrer Institute, 5232 Villigen, Switzerland and University of Bern, 3012 Bern, Switzerland
| | - J Uusitalo
- University of Jyväskylä, 40351 Jyväskylä, Finland
| | - D E Ward
- Lund University, 22100 Lund, Sweden
| | - M Wegrzecki
- Institute of Electron Technology, 02-668 Warsaw, Poland
| | - N Wiehl
- Helmholtz Institute Mainz, 55099 Mainz, Germany and Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - S M Van Cleve
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - V Yakusheva
- Helmholtz Institute Mainz, 55099 Mainz, Germany
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Rudolph D, Forsberg U, Golubev P, Sarmiento LG, Yakushev A, Andersson LL, Di Nitto A, Düllmann CE, Gates JM, Gregorich KE, Gross CJ, Heßberger FP, Herzberg RD, Khuyagbaatar J, Kratz JV, Rykaczewski K, Schädel M, Åberg S, Ackermann D, Block M, Brand H, Carlsson BG, Cox D, Derkx X, Eberhardt K, Even J, Fahlander C, Gerl J, Jäger E, Kindler B, Krier J, Kojouharov I, Kurz N, Lommel B, Mistry A, Mokry C, Nitsche H, Omtvedt JP, Papadakis P, Ragnarsson I, Runke J, Schaffner H, Schausten B, Thörle-Pospiech P, Torres T, Traut T, Trautmann N, Türler A, Ward A, Ward DE, Wiehl N. Spectroscopy of element 115 decay chains. Phys Rev Lett 2013; 111:112502. [PMID: 24074079 DOI: 10.1103/physrevlett.111.112502] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Indexed: 06/02/2023]
Abstract
A high-resolution α, x-ray, and γ-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated α-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z=115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z>112. Comprehensive Monte Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.
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Greenlees PT, Rubert J, Piot J, Gall BJP, Andersson LL, Asai M, Asfari Z, Cox DM, Dechery F, Dorvaux O, Grahn T, Hauschild K, Henning G, Herzan A, Herzberg RD, Heßberger FP, Jakobsson U, Jones P, Julin R, Juutinen S, Ketelhut S, Khoo TL, Leino M, Ljungvall J, Lopez-Martens A, Lozeva R, Nieminen P, Pakarinen J, Papadakis P, Parr E, Peura P, Rahkila P, Rinta-Antila S, Ruotsalainen P, Sandzelius M, Sarén J, Scholey C, Seweryniak D, Sorri J, Sulignano B, Theisen C, Uusitalo J, Venhart M. Shell-structure and pairing interaction in superheavy nuclei: rotational properties of the z=104 nucleus (256)rf. Phys Rev Lett 2012; 109:012501. [PMID: 23031099 DOI: 10.1103/physrevlett.109.012501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Indexed: 06/01/2023]
Abstract
The rotational band structure of the Z=104 nucleus (256)Rf has been observed up to a tentative spin of 20ℏ using state-of-the-art γ-ray spectroscopic techniques. This represents the first such measurement in a superheavy nucleus whose stability is entirely derived from the shell-correction energy. The observed rotational properties are compared to those of neighboring nuclei and it is shown that the kinematic and dynamic moments of inertia are sensitive to the underlying single-particle shell structure and the specific location of high-j orbitals. The moments of inertia therefore provide a sensitive test of shell structure and pairing in superheavy nuclei which is essential to ensure the validity of contemporary nuclear models in this mass region. The data obtained show that there is no deformed shell gap at Z=104, which is predicted in a number of current self-consistent mean-field models.
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Affiliation(s)
- P T Greenlees
- Department of Physics, University of Jyväskylä, FIN-40014 Jyväskylä, Finland.
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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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