Experimental Study of the 238U(36S,3-5n)269-271Hs Reaction Leading to the Observation of 270Hs

Research output: Contribution to journalArticle

Abstract

The deformed doubly magic nucleus (270)Hs has so far only been observed as the four-neutron (4n) evaporation residue of the reaction Mg-26+Cm-248, where a maximum cross section of 3 pb was measured. Theoretical studies on the formation of (270)Hs 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 Ca-48+Ra-226 and S-36+U-238 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 S-36+U-238 that are similar to those of the Mg-26+Cm-248 reaction. Here, we report on the first measurement of evaporation residues formed in the complete nuclear fusion reaction S-36+U-238 and the observation of (270)Hs, which is produced in the 4n evaporation channel, with a measured cross section of 0.8(-0.7)(+2.6) 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 Mg-26+Cm-248 reaction at similar excitation energy.

Details

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

Subject classification (UKÄ) – MANDATORY

  • Subatomic Physics
Original languageEnglish
Article number061601(R)
JournalPhysical Review C (Nuclear Physics)
Volume81
Issue number6
Publication statusPublished - 2010
Publication categoryResearch
Peer-reviewedYes