Experimental study of the U238 (S36 , 3-5n) Hs269-271 reaction leading to the observation of Hs270

Graeger, R.; Ackermann, D.; Chelnokov, M.; Chepigin, V.; Düllmann, Ch. E.; Dvorak, J.; Even, J.; Gorshkov, A.; Heßberger, F. P.; Hild, D.; Hübner, A.; Jäger, E.; Khuyagbaatar, J.; Kindler, B.; Kratz, J. V.; Krier, J.; Kuznetsov, A.; Lommel, B.; Nishio, K.; Nitsche, H.; Omtvedt, J. P.; Petrushkin, O.; Rudolph, D.; Runke, J.; Samadani, F.; Schädel, M.; Schausten, B.; Türler, A.; Yakushev, A.; Zhi, Q.

doi:10.1103/PhysRevC.81.061601

Title: Experimental study of the ${}^{238}U$ ( ${}^{36}S$ , $3 - 5 n$ ) ${}^{269 - 271}{Hs}$ reaction leading to the observation of ${}^{270}{Hs}$

Journal Article · Thu Jun 03 00:00:00 EDT 2010 · Physical Review C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.81.061601· OSTI ID:1511320

Graeger, R. ^[1]; Ackermann, D. ^[2]; Chelnokov, M. ^[3]; Chepigin, V. ^[3]; Düllmann, Ch. E. ^[2]; Dvorak, J. ^[4]; Even, J. ^[5]; Gorshkov, A. ^[1]; Heßberger, F. P. ^[2]; Hild, D. ^[5]; Hübner, A. ^[2]; Jäger, E. ^[2]; Khuyagbaatar, J. ^[2]; Kindler, B. ^[2]; Kratz, J. V. ^[5]; Krier, J. ^[2]; Kuznetsov, A. ^[3]; Lommel, B. ^[2]; Nishio, K. ^[6]; Nitsche, H. ^[7] more »

Technische Univ. Munchen, Garching (Germany)
GSI-Helmholtzzentrum fur Schwerionenforschung, Darmstadt (Germany)
Joint Inst. for Nuclear Research (JINR), Dubna (Russian Federation)
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Johannes Gutenberg Univ., Mainz (Germany)
Japan Atomic Energy Agency (JAEA), Tokai (Japan)
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
Univ. of Oslo (Norway)
GSI-Helmholtzzentrum fur Schwerionenforschung, Darmstadt (Germany); Johannes Gutenberg Univ., Mainz (Germany); Lund Univ. (Sweden)
Chinese Academy of Sciences (CAS), Lanzhou (China)

The deformed doubly magic nucleus ²⁷⁰Hs has so far only been observed as the four-neutron (4n) evaporation residue of the reaction ²⁶Mg+²⁴⁸Cm, where a maximum cross section of 3 pb was measured. Theoretical studies on the formation of ²⁷⁰Hs in the 4n evaporation channel of fusion reactions with different entrance channel asymmetry in the framework of a two-parameter Smoluchowski equation predict that the reactions ⁴⁸Ca+²²⁶Ra and ³⁶S+²³⁸U result in higher cross sections due to lower reaction Q values, in contrast to simple arguments based on the reaction asymmetry, which predict opposite trends. Calculations using hivap predict cross sections for the reaction ³⁶S+²³⁸U that are similar to those of the ²⁶Mg+²⁴⁸Cm reaction. Here, we report on the first measurement of evaporation residues formed in the complete nuclear fusion reaction ³⁶S+²³⁸U and the observation of ²⁷⁰Hs, which is produced in the 4n evaporation channel, with a measured cross section of 0.8$$ +2.6\atop{-0.7} $$ pb at 51-MeV excitation energy. The one-event cross-section limits (68% confidence level) for the 3n, 4n, and 5n evaporation channels at 39-MeV excitation energy are 2.9 pb, while the cross-section limits of the 3n and 5n channel at 51 MeV are 1.5 pb. This is significantly lower than the 5n cross section of the ²⁶Mg+²⁴⁸Cm reaction at similar excitation energy.

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Research Organization:: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Organization:: USDOE Office of Science (SC), High Energy Physics (HEP)

DOE Contract Number:: AC02-05CH11231

OSTI ID:: 1511320

Journal Information:: Physical Review C, Nuclear Physics, Vol. 81, Issue 6; ISSN 0556-2813

Publisher:: American Physical Society (APS)

Country of Publication:: United States

Language:: English

References (25)

IVO, a device for In situ Volatilization and On-line detection of products from heavy ion reactions Düllmann, Ch. E.; Eichler, B.; Eichler, R. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 479, Issue 2-3 https://doi.org/10.1016/S0168-9002(01)00898-1	journal	March 2002
The processes of fusion-fission and quasi-fission of superheavy nuclei Itkis, M. G.; Bogachev, A. A.; Itkis, I. M. Nuclear Physics A, Vol. 787, Issue 1-4 https://doi.org/10.1016/j.nuclphysa.2006.12.026	journal	May 2007
Superheavy nuclei in self-consistent nuclear calculations Rutz, K.; Bender, M.; Bürvenich, T. Physical Review C, Vol. 56, Issue 1 https://doi.org/10.1103/PhysRevC.56.238	journal	July 1997
Synthesis of rutherfordium isotopes in the ${}^{238}U$ ( ${}^{26}{Mg}$ , $xn)^{264 − x} Rf$ reaction and study of their decay properties Gates, J. M.; Garcia, M. A.; Gregorich, K. E. Physical Review C, Vol. 77, Issue 3 https://doi.org/10.1103/PhysRevC.77.034603	journal	March 2008
Some remarks on the error analysis in the case of poor statistics Schmidt, K. -H.; Sahm, C. -C.; Pielenz, K. Zeitschrift f�r Physik A Atoms and Nuclei, Vol. 316, Issue 1 https://doi.org/10.1007/BF01415656	journal	February 1984
Erratum: $^{248} Cm (^{22} Ne, xn)^{270 − x} Sg$ reaction and the decay properties of $^{265} Sg$ reexamined [Phys. Rev. C 77 , 064320 (2008)] Düllmann, Ch. E.; Türler, A. Physical Review C, Vol. 78, Issue 2 https://doi.org/10.1103/PhysRevC.78.029901	journal	August 2008
The Ame2003 atomic mass evaluation Audi, G.; Wapstra, A. H.; Thibault, C. Nuclear Physics A, Vol. 729, Issue 1 https://doi.org/10.1016/j.nuclphysa.2003.11.003	journal	December 2003
Ground-state properties of the heaviest nuclei analyzed in a multidimensional deformation space Patyk, Zygmunt; Sobiczewski, Adam Nuclear Physics A, Vol. 533, Issue 1 https://doi.org/10.1016/0375-9474(91)90823-O	journal	October 1991
Nuclear properties according to the Thomas-Fermi model Myers, W. D.; Swiatecki, W. J. Nuclear Physics A, Vol. 601, Issue 2 https://doi.org/10.1016/0375-9474(95)00509-9	journal	May 1996
On the decay properties of 269Hs and indications for the new nuclide 270Hs Türler, A.; Düllmann, Ch. E.; Gäggeler, H. W. The European Physical Journal A, Vol. 17, Issue 4 https://doi.org/10.1140/epja/i2002-10163-0	journal	August 2003
Chemical investigation of hassium (element 108) Düllmann, Ch. E.; Brüchle, W.; Dressler, R. Nature, Vol. 418, Issue 6900 https://doi.org/10.1038/nature00980	journal	August 2002
Cross section limits for the ${}^{248}{Cm} ({}^{25}{Mg}, 4 n − 5 n) {}^{268, 269}{Hs}$ reactions Dvorak, J.; Brüchle, W.; Düllmann, Ch. E. Physical Review C, Vol. 79, Issue 3 https://doi.org/10.1103/PhysRevC.79.037602	journal	March 2009
New isotope ${}^{264}{Sg}$ and decay properties of ${}^{262 - 264}{Sg}$ Gregorich, K. E.; Gates, J. M.; Düllmann, Ch. E. Physical Review C, Vol. 74, Issue 4 https://doi.org/10.1103/PhysRevC.74.044611	journal	October 2006
Evidence of Complete Fusion in the Sub-Barrier ${}^{16}O + {}^{238}U$ Reaction Nishio, K.; Ikezoe, H.; Nagame, Y. Physical Review Letters, Vol. 93, Issue 16 https://doi.org/10.1103/PhysRevLett.93.162701	journal	October 2004
The Cryo-Thermochromatographic Separator (CTS): Kirbach, U. W.; Folden III, C. M.; Ginter, T. N. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 484, Issue 1-3 https://doi.org/10.1016/S0168-9002(01)01990-8	journal	May 2002
Doubly Magic Nucleus ${}_{108}^{270}{Hs}_{162}$ Dvorak, J.; Brüchle, W.; Chelnokov, M. Physical Review Letters, Vol. 97, Issue 24 https://doi.org/10.1103/PhysRevLett.97.242501	journal	December 2006
Synthesis of superheavy nuclei: A search for new production reactions Zagrebaev, Valery; Greiner, Walter Physical Review C, Vol. 78, Issue 3 https://doi.org/10.1103/PhysRevC.78.034610	journal	September 2008
Attempts to chemically investigate element 112 Eichler, R.; Brüchle, W.; Buda, R. Radiochimica Acta, Vol. 94, Issue 4 https://doi.org/10.1524/ract.2006.94.4.181	journal	January 2006
Observation of the $3 n$ Evaporation Channel in the Complete Hot-Fusion Reaction ${}^{26}{Mg} + {}^{248}{Cm}$ Leading to the New Superheavy Nuclide ${}^{271}{Hs}$ Dvorak, J.; Brüchle, W.; Chelnokov, M. Physical Review Letters, Vol. 100, Issue 13 https://doi.org/10.1103/PhysRevLett.100.132503	journal	April 2008
$Q$ -value effects on the production of superheavy nuclei Liu, Z. H.; Bao, Jing-Dong Physical Review C, Vol. 74, Issue 5 https://doi.org/10.1103/PhysRevC.74.057602	journal	November 2006
Srim-2003 Ziegler, James F. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 219-220 https://doi.org/10.1016/j.nimb.2004.01.208	journal	June 2004
Measurement of evaporation residue cross-sections of the reaction 30Si + 238U at subbarrier energies Nishio, K.; Hofmann, S.; Heßberger, F. P. The European Physical Journal A, Vol. 29, Issue 3 https://doi.org/10.1140/epja/i2006-10091-y	journal	September 2006
How well do we understand the synthesis of heavy elements by heavy-ion induced fusion? Reisdorf, W.; Sch�del, M. Zeitschrift f�r Physik A Hadrons and Nuclei, Vol. 343, Issue 1 https://doi.org/10.1007/BF01291597	journal	March 1992
Effects of nuclear orientation on the mass distribution of fission fragments in the reaction of ${}^{36}S + {}^{238}U$ Nishio, K.; Ikezoe, H.; Mitsuoka, S. Physical Review C, Vol. 77, Issue 6 https://doi.org/10.1103/PhysRevC.77.064607	journal	June 2008
Shell structure of the superheavy elements Ćwiok, S.; Dobaczewski, J.; Heenen, P. -H. Nuclear Physics A, Vol. 611, Issue 2-3 https://doi.org/10.1016/S0375-9474(96)00337-5	journal	December 1996