17-21 July 2017
Santiago de Compostela, Facultade de Química
Europe/Madrid timezone

Dissipative effects in fission investigated in complete kinematics measurements

17 Jul 2017, 16:25
Aula Química Física (Facultade de Química (USC))

Aula Química Física

Facultade de Química (USC)

Nuclear Physics Nuclear Physics I


Mr. Jose Luis Rodriguez Sanchez (USC)


A complete description of the fission process still represents a challenge, despite the recent progress based on time-dependent Hartree-Fock models [1]. Statistical models provide a tool to describe fission probabilities at excitation energies around the fission barrier. This approach is justified because, under such conditions, statistical times dominate over the typical timescales for the coupling between intrinsic and collective degrees of freedom (~10-21s). At high excitation energies, pre- and postscission particle emission and fission probabilities [2,3] indicate that simple statistical approaches are not valid and models, describing the dynamics of the process, are required. These models are based on transport equations, e.g. Fokker-Planck or Langevin, where the main ingredients are the potential landscape and the friction and inertia tensors [4]. The friction parameter is particularly interesting because it quantifies the magnitude of the coupling between collective and intrinsic degrees of freedom in fission. In this work, we propose to investigate these effects by taking advantage of proton-induced fission reactions at relativistic energies for producing highly-excited fissioning nuclei with low angular momentum, where dissipative effects should manifest in a clear way. The SOFIA setup together with the inverse kinematics technique were used for the first time to measure in coincidence the mass and atomic number of the two fission fragments with good resolution [5]. These high-quality data allowed us to obtain new observables in fission. In particular, total and partial fission cross sections and the charge distribution of the fission fragments are used to characterize the fission dynamics at small deformation [6]. Moreover, we will also present the results concerning the neutron excess and the average pre- and postneutron multiplicities, which help us to investigate the postsaddle dynamics [7]. References [1] G. Scamps et al., Phys. Rev. C 91, (2015) 044606 [2] J. P. Lestone et al., Phys. Rev. C 79, (2009) 044611 [3] J. Benlliure et al., Phys. Rev. C 74, (2008) 014609 [4] P. N. Nadtochy et al., Phys. Rev. C 65, (2002) 064615 [5] J. L. Rodríguez-Sánchez et al., Phys. Rev. C 91, (2015) 064616 [6] J. L. Rodríguez-Sánchez et al., Phys. Rev. C 92, (2015) 044612 [7] J. L. Rodríguez-Sánchez et al., Phys. Rev. C 94, (2016) 061601(R)

Primary author

Mr. Jose Luis Rodriguez Sanchez (USC)

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