Observation of the competing fission modes in 178 Pt

Igor Tsekhanovich, A. N. Andreyev, K. Nishio, D. Denis-Petit, K. Hirose, H. Makii, Z. Matheson, K. Morimoto, K. Morita, W. Nazarewicz, R. Orlandi, J. Sadhukhan, T. Tanaka, M. Vermeulen, M. Warda

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Fragment mass distributions from fission of the excited compound nucleus 178 Pt have been deduced from the measured fragment velocities. The 178 Pt nucleus was created at the JAEA tandem facility in a complete fusion reaction 36 Ar + 142 Nd, at beam energies of 155, 170 and 180 MeV. The data are indicative of a mixture of the mass-asymmetric and mass-symmetric fission modes associated with higher and lower total kinetic energies of the fragments, respectively. The measured fragment yields are dominated by asymmetric mass splits, with the symmetric mode contributing at the level of ≈1/3. This constitutes the first observation of a multimodal fission in the sub-lead region. Most probable experimental fragment-mass split of the asymmetric mode, A L /A H ≈79/99, is well reproduced by nuclear density functional theory using the UNEDF1-HFB and D1S potentials. The symmetric mode is associated by theory with very elongated fission fragments, which is consistent with the observed total kinetic energy/fragment mass correlation.

Original languageEnglish
Pages (from-to)583-588
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Early online date12 Feb 2019
Publication statusE-pub ahead of print - 12 Feb 2019

Bibliographical note

© 2019 The Authors.


  • Pt
  • Fusion–fission
  • Symmetric and asymmetric fission modes

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