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Gates JM, Pang GK, Pore JL, Gregorich KE, Kwarsick JT, Savard G, Esker NE, Kireeff Covo M, Mogannam MJ, Batchelder JC, Bleuel DL, Clark RM, Crawford HL, Fallon P, Hubbard KK, Hurst AM, Kolaja IT, Macchiavelli AO, Morse C, Orford R, Phair L, Stoyer MA. First Direct Measurements of Superheavy-Element Mass Numbers. Phys Rev Lett 2018; 121:222501. [PMID: 30547624 DOI: 10.1103/physrevlett.121.222501] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 09/07/2018] [Indexed: 06/09/2023]
Abstract
An experiment was performed at Lawrence Berkeley National Laboratory's 88-in. Cyclotron to determine the mass number of a superheavy element. The measurement resulted in the observation of two α-decay chains, produced via the ^{243}Am(^{48}Ca,xn)^{291-x}Mc reaction, that were separated by mass-to-charge ratio (A/q) and identified by the combined BGS+FIONA apparatus. One event occurred at A/q=284 and was assigned to ^{284}Nh (Z=113), the α-decay daughter of ^{288}Mc (Z=115), while the second occurred at A/q=288 and was assigned to ^{288}Mc. This experiment represents the first direct measurements of the mass numbers of superheavy elements, confirming previous (indirect) mass-number assignments.
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Affiliation(s)
- J M Gates
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - G K Pang
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - J L Pore
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - K E Gregorich
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - J T Kwarsick
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- University of California, Berkeley, California 94720, USA
| | - G Savard
- Argonne National Laboratory, Argonne, Illinois 60439, USA
- University of Chicago, Chicago, Illinois 60637, USA
| | - N E Esker
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - M Kireeff Covo
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - M J Mogannam
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - J C Batchelder
- University of California, Berkeley, California 94720, USA
| | - D L Bleuel
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R M Clark
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - H L Crawford
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - P Fallon
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - K K Hubbard
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- University of California, Berkeley, California 94720, USA
| | - A M Hurst
- University of California, Berkeley, California 94720, USA
| | - I T Kolaja
- University of California, Berkeley, California 94720, USA
| | - A O Macchiavelli
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - C Morse
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R Orford
- Argonne National Laboratory, Argonne, Illinois 60439, USA
- McGill University, Montreal, Québec H3A 0G4, Canada
| | - L Phair
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - M A Stoyer
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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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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