Experimental evidence of the effect of nuclear shells on fission dissipation and time

Abstract

Nuclear fission is still one of the most complex physical processes we can observe in nature due to the interplay of macroscopic and microscopic nuclear properties that decide the result. An example of this coupling is the presence of nuclear dissipation as an important ingredient that contributes to drive the dynamics and has a clear impact on the time of the process. However, different theoretical interpretations, and scarce experimental data make it poorly understood. In this letter, we present the first experimental determination of the dissipation energy in fission as a function of the fragment split, for three different fissioning systems. The amount of dissipation was obtained through the measurement of the relative production of fragments with even and odd atomic numbers with respect to different initial fission energies. The results reveal a clear effect of particular nuclear shells on the dissipation and fission dynamics. In addition, the relative production of fragments with even and odd atomic numbers appears as a potential contributor to the long-standing problem of the time scale in fission.

References in corpus (15)

• Induced Fission of ${}^{240}$Pu within a Real-Time Microscopic Framework
• Review on the progress in nuclear fission
• Future of Nuclear Fission Theory
• Formation and dynamics of fission fragments
• Entropy-driven excitation-energy sorting in superfluid fission dynamics
• Fission Hindrance in hot 216Th: Evaporation Residue Measurements
• Theory of Nuclear Fission
• Fission Dynamics of 240Pu from Saddle-to-Scission and Beyond
• Characterization of the scission point from fission-fragment velocities
• Transfer reactions in inverse kinematics, an experimental approach for fission investigations
• Influence of complete energy sorting on the characteristics of the odd-even effect in fission-fragment element distributions
• New dynamical pair breaking effect
• Scission configuration of ${}^{239}$U from yields and kinetic information of fission fragments
• Microscopic description of the odd-even effect in cold fission
• Methods for a quantitative evaluation of odd-even staggering effects

Cited by in corpus (4)

• Fourier-over-Spheroid shape parametrization applied to nuclear fission dynamics
• Shell Effects in Quasi-fission in Reactions Forming 226Th Compound Nucleus
• Isotopic fission yields of ${}^{240}$Pu as a function of the excitation energy
• Performance of the Particle-Identification Silicon-Telescope Array Coupled with the VAMOS++ Magnetic Spectrometer