Analysis of the total kinetic energy of fission fragments with the Langevin equation

Abstract

We analyzed the total kinetic energy (TKE) of fission fragments with three-dimensional Langevin calculations for a series of actinides and Fm isotopes at various excitation energies. This allowed us to establish systematic trends of TKE with Z 2 /A 1/3 of the fissioning system and as a function of excitation energy. In the mass-energy distributions of fission fragments we see the contributions from the standard, super-long and super-short (in the case of 258 Fm) fission modes. For the fission fragments mass distribution of 258 Fm we obtained a single peak mass distribution. The decomposition of TKE into the prescission kinetic energy and Coulomb repulsion showed that decrease of TKE with growing excitation energy is accompanied by a decrease of prescission kinetic energy. It was also found that transport coefficients (friction and inertia tensors) calculated by a microscopic model and by macroscopic models give drastically different behavior of TKE as a function of excitation energy. The results obtained with microscopic transport coefficients are much closer to experimental data than those calculated with macroscopic ones.

Correlated transitions in TKE and mass distributions of fission fragments described by 4-D Langevin equation

“…Recently, we have introduced the microscopic mass and friction tensors to improve the calculations of 3-D Langevin equation 7 instead of the usual macroscopic mass and friction tensors 11–13 . With it, we see the average total kinetic energy 〈TKE〉 decreasing with larger excitation energy E x and the influence of pairing at smaller E x 3 . There are some deficiencies with the 3-D Langevin model because we were unable to observe the expected transition from double peak fission yield of 256 Fm to the single peak fission yield 258 Fm, and the TKE as a function fragment mass TKE( A ) are rather poor.…”

Cluster radioactivity of Og176118294

“…In this work, we set the dissipation strength η ij as an adjustable parameter rather than using some of the common prescriptions [52,53], which have not yet been adapted to DFT inputs. We examined the sensitivity of our calculations to η ij by varying it around the baseline value used in [22]: η 0 ≡ (η 22 , η 23 , η 33 ) ≡ (50 , 5 , 40 ).…”

Measurement of fission-fragment mass distributions in the multinucleon transfer channels of theO18+Np237reaction

“…Recently, Langevin calculations have been extensively adopted for the study of low-energy fission [3,[12][13][14][15][16][17][18][19][20]. In particular, thanks to the high predictive power for the FFMD calculation, the Langevin approach was used to discuss the importance of the multi-chance fission at high excitation energies [2,3].…”