Elsevier

Nuclear Physics A

Volume 568, Issue 1, 7 February 1994, Pages 121-140
Nuclear Physics A

Production of heavy residues in nuclear collisions leading to Zp + Zt ⩾ 75 at bombarding energies of E/A = (11.4–15.3) MeV/u

https://doi.org/10.1016/0375-9474(94)90007-8Get rights and content

Abstract

Heavy residues, produced in 40Ar, 84Kr and 86Kr induced reactions at E/A = 14.5 MeV/u, E/A = 11.6 MeV/u and E/A = 11A MeV/u, respectively, have been separated from the projectile beam by the velocity filter SHIP and identified by means of α-spectroscopy. The observed reaction products were assigned to evaporation residues from compound or compound-like nuclei up to Z = 96 rather than from products from deep-inelastic processes. This interpretation is based on the velocity distributions, which peak close to νCN, the independence of the residue mass distributions from the entrance channel, and from comparisons of the observed mass distributions with results from statistical model calculations.

The observed residue cross sections were found to be in the same order as or even higher than the values obtained at bombarding energies close to the fusion barrier. This we regard as a confirmation that fission is a process of low probability at high excitation energies.

An analysis of the velocity distributions of the evaporation residues showed that particle emission from a thermally equilibrated compound nucleus dominates; contributions from preequilibrium emission are small.

References (45)

  • K. Siwek-Wilczynska et al.

    Nucl. Phys.

    (1979)
  • H. Morgenstern et al.

    Phys. Lett.

    (1982)
  • J. Wilczynski et al.

    Nucl. Phys.

    (1982)
  • C. Cerruti et al.

    Nucl. Phys.

    (1986)
  • B. Borderie et al.

    Nucl. Phys.

    (1983)
  • D.J. Hinde et al.

    Nucl. Phys.

    (1986)
  • G. Münzenberg et al.

    Nucl. Instr. Meth.

    (1979)
  • W. Faust et al.

    Nucl. Instr. Meth.

    (1979)
  • W. Reisdorf et al.

    Nucl. Phys.

    (1985)
  • C. Gregoire et al.

    Ann. de Phys.

    (1986)
  • V.E. Viola et al.

    Phys. Rev.

    (1982)
  • H. Morgenstern et al.

    Z. Phys.

    (1983)
  • H. Morgenstern et al.

    Phys. Rev. Lett.

    (1984)
  • L.E. Tubbs et al.

    Phys. Rev.

    (1985)
  • A. Fahli et al.

    Phys. Rev.

    (1986)
  • M.F. Rivet et al.

    Phys. Rev.

    (1986)
  • D. Hilscher et al.

    Phys. Rev.

    (1987)
  • G.M. Berkowitz et al.

    Phys. Rev.

    (1981)
  • H. Machner et al.

    Phys. Rev.

    (1985)
  • H. Fuchs et al.

    Phys. Rev.

    (1985)
  • E. Holub et al.

    Phys. Rev.

    (1986)
  • W.P. Zank et al.

    Phys. Rev.

    (1986)
  • 1

    Present Address: Institute Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro, Padua, Italy.

    Deceased on January, 6th, 1993.

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