A simplified two-dimensional diffusion model for calculating the fission-fragment kinetic-energy distribution

Abstract

The variance 0 .2 of the fission-fragment kinetic-energy distribution is calculated in Ek describing the dynamics of fission of an excited nucleus by a Fokker-Planck equation for the quantum distribution function of two collective coordinates (the distance between the centers of mass of the nascent fragments and the neck parameter) and their conjugate momenta. In the calculations fluctuations in collective coordinates near scission and prescission kinetic energy have been taken into account simultaneously. The results of statistical model calculations for the case of high friction in fission mode and those of the calculations in the framework of a dynamical model for zero nuclear viscosity are the limiting cases of the proposed model. The dependence of a2 upon the fissility parameter is studied.

Systematic studies of fission fragment kinetic energy distributions by Langevin simulations

“…We consider a correction of a finite neck radius on the TKE formula (17) in this paper, therefore, the friction coefficient has the value t/0 = (1.2 _+ 0.3) 10-23 MeV fm-3, which is found between two values corresponding to a zero neck radius [14] and a finite neck radius [19] as scission conditions. Firstly, we study the TKE of the compound nucleus 233pu (the fission barrier height B I = 4.02 MeV) with 5.104 trajectories by using two methods: (1) The complete Langevin simulation starting from the ground state (LSGS) with the initial condition shown in formula (13); (2) The Langevin simulation starting from the saddle point (LSSP) in which the initial distribution at the saddle point is approximated as in [20,21]:…”

Application of Spectrometry and Spectroscopy to Time Scale Analysis in Astrochemistry

“…Around 200 years ago Joseph von Fraunhofer developed production of very pure prisms that allowed observation of dark lines in continuous spectrum and in combination with the telescope to observe the stellar and planets' spectrum and led to finding element Hellium in the Sun's spectrum 150 years ago, a year before publication of the first Periodic Table of Elements by Mendeleev. Only after 27 years this colorless and odorless element was found on Earth [36,37].…”

Total kinetic energy release in the fast neutron induced fission of actinide nuclei

“…The Folker-Plank equation is also the basis of papers describing the massenergy distributions of fission fragments and the dependences of the mean kinetic energy for a wide variety of heavy nuclei ranging from Hg to Pu [49]. A two-dimensional diffusion model is also used to describe the TKE release [50].…”