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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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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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Eichler R, Brüchle W, Buda R, Bürger S, Dressler R, Düllmann CE, Dvorak J, Eberhardt K, Eichler B, Folden CM, Gäggeler HW, Gregorich KE, Haenssler F, Hoffman DC, Hummrich H, Jäger E, Kratz JV, Kuczewski B, Liebe D, Nayak D, Nitsche H, Piguet D, Qin Z, Rieth U, Schädel M, Schausten B, Schimpf E, Semchenkov A, Soverna S, Sudowe R, Trautmann N, Thörle P, Türler A, Wierczinski B, Wiehl N, Wilk PA, Wirth G, Yakushev AB, von Zweidorf A. Attempts to chemically investigate element 112. RADIOCHIM ACTA 2009. [DOI: 10.1524/ract.2006.94.4.181] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Summary
Two experiments aiming at the chemical investigation of element 112 produced in the heavy ion induced nuclear fusion reaction of 48Ca with 238U were performed at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt, Germany. Both experiments were designed to determine the adsorption enthalpy of element 112 on a gold surface using a thermochromatography setup. The temperature range covered in the thermochromatography experiments allowed the adsorption of Hg at about 35 °C and of Rn at about -180 °C. Reports from the Flerov Laboratory for Nuclear Reactions (FLNR), Dubna, Russia claim production of a 5-min spontaneous fission (SF) activity assigned to 283112 for the 238U(48Ca,3n) 283112 reaction. Hence, Experiment I was designed to detect spontaneously fissioning (SF) isotopes of element 112 with half-lives (t
1/2) longer than about 20 s. 11 high-energy events were detected. 7 events exhibit a deposition pattern resembling a chromatographic peak in the vicinity of Rn deposition. However, the energy of the events observed in Experiment I was lower than expected for a SF-decay of 283112. Therefore, these events could not be unambiguously attributed to the decay of 283112. In contradiction with earlier publications newer reports from FLNR Dubna claim that 283112 decays by α-particle emission (E
α = 9.5 MeV) with t
1/2 = 4 s followed by a SF-decay of 279Ds (t
1/2 = 0.2 s). Therefore, Experiment II was designed to be sensitive to both claimed decay properties of 283112. However, during this experiment neither short α-SF correlations nor SF coincidences were detected. The conclusion is that 283112 was not unambiguously detected, neither in Experiment I nor in Experiment II.
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