Zeitschrift für Physik A Atomic Nuclei

, Volume 324, Issue 4, pp 489–490

Evidence for264108, the heaviest known even-even isotope

  • G. Münzenberg
  • P. Armbruster
  • G. Berthes
  • H. Folger
  • F. P. He\berger
  • S. Hofmann
  • K. Poppensieker
  • W. Reisdorf
  • B. Quint
  • K. -H. Schmidt
  • H. -J. Schött
  • K. Sümmerer
  • I. Zychor
  • M. E. Leino
  • U. Gollerthan
  • E. Hanelt
Short Note

Conclusion

We have observed the decay of one atom of the doubly even isotope 108. We observed α-decay with a halflife, of (76−36+364) Μs. The full α-decay energy could not be measured, as the α escaped the detector. With the knowledge of the halflife, an estimate on the α-decay energy can be made.

From the formula of Rasmussen9 and a reduced α-width of 1, a value which has been measured for260106 and also for the doubly even isotones of N=156, we obtain Q=(11.0−0.3+0.1 MeV. This value is higher than given by Moeller10 (10.35 MeV), and agrees with that of Uran and Zeldes11 (10.9 MeV). A hindrance factor wα of 0.5 increases the Qα-value by 0.14 MeV. The mass excess of264108 follows as (120.0±0.3) MeV. The groundstate shell effect amounts to (−5.0±0.3) MeV using the macroscopic mass values of Ref. 10. The formation cross section of (3.2−2.6+6.1) pb overlaps with the value of ∼ 5 pb from Dubna for the 6 ms sf-activity mentioned initially but is considerably lower than an extrapolation from the reaction58Fe (208Pb,n)265108 which gave 10 pb with the lower limit of 4 pb.

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Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • G. Münzenberg
    • 1
  • P. Armbruster
    • 1
  • G. Berthes
    • 1
  • H. Folger
    • 1
  • F. P. He\berger
    • 1
  • S. Hofmann
    • 1
  • K. Poppensieker
    • 1
  • W. Reisdorf
    • 1
  • B. Quint
    • 1
  • K. -H. Schmidt
    • 1
  • H. -J. Schött
    • 1
  • K. Sümmerer
    • 1
  • I. Zychor
    • 1
  • M. E. Leino
    • 2
  • U. Gollerthan
    • 3
  • E. Hanelt
    • 3
  1. 1.Gesellschaft für Schwerionenforschung mbHDarmstadtFederal Republic of Germany
  2. 2.University of HelsinkiHelsinkiFinland
  3. 3.Institut für KernphysikTechnische Hochschule DarmstadtDarmstadtFederal Republic of Germany

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