Measurement of the survival probabilities for hot fusion reactions.
We have studied the fission-neutron emission competition in highly excited (274)Hs (Z=108) (where the fission barrier is due to shell effects) formed by a hot fusion reaction. Matching cross bombardments ((26)Mg+(248)Cm and (25)Mg+(248)Cm) were used to identify the properties of first chance fission of (274)Hs. A Harding-Farley analysis of the fission neutrons emitted in the (25)Mg,26+(248)Cm was performed to identify the prescission and postscission components of the neutron multiplicities in each system. (Γn/Γt) for the first chance fission of (274)Hs (E*=63  MeV) is 0.89±0.13; i.e., ∼90% of the highly excited nuclei survive. The high value of that survival probability is due to dissipative effects during deexcitation. A proper description of the survival probabilities of excited superheavy nuclei formed in hot fusion reactions requires consideration of both dynamic and static (shell-related) effects.
Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA.
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R
Yanez
Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA.
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W
Loveland
Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA.
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L
Yao
Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA.
J S
JS
Barrett
Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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S
Zhu
Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
B B
BB
Back
Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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TL
Khoo
Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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M
Alcorta
Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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M
Albers