Monte Carlo studies of alpha-accompanied fission (original) (raw)
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Transient effects in highly-excited fissioning systems
Journal of Physics: Conference Series, 2014
In this work we report the proton-and deuteron-induced fission of 208 Pb at 500A MeV in inverse kinematics. We obtained two observables that allow us to investigate dynamical effects in the fission process: partial fission cross sections and the width of the fission fragment charge distribution as a function of the atomic number of the fissioning system. Results are compared to nuclear reaction model calculations in order to describe the evolution of the system from ground to saddle.
Fission of highly excited nuclei investigated in complete kinematic measurements
Fission is an extremely complex mechanism that requires a dynamical approach to describe the evolution of the process in terms of intrinsic and collective excitations of the nuclear constituents. In order to determine these effects a complex experimental setup was mounted at GSI, which allowed us for the first time the full identification in charge and mass of all fission fragments thanks to a magnetic separation and the use of the inverse kinematic technique. Moreover, we also measured the neutron multiplicities and the light-charged particles emitted in coincidence with fission. These complete kinematic measurements will be used to define sensitive observables to dissipative and transient effects in fission. In this manuscript we present the first results for the total fission cross sections. Reactions p+ Bychenkov V.S. Konshin V. A. Kotov A.A. Brandt R. Hagebo E. Gloris M. Pb+p 208 Reactions This work
Monte Carlo Hauser-Feshbach predictions of prompt fission γ rays: Application to nth+235U, <sp...
Physical Review C, 2013
The prompt neutron and γ emission from primary fission fragments are calculated for thermal neutron induced fission of 235 U and 239 Pu and for spontaneous fission of 252 Cf using a Monte Carlo Hauser-Feshbach approach for the evaporation of the excited fission fragments. Remaining free model parameters, such as excitation energy sharing and initial spin distribution, are determined by comparison of the neutron emission characteristics with experimental data. Using the obtained parameters the γ -ray characteristics, e.g., γ spectrum, multiplicity distribution, average multiplicity and energy, and multiplicity distribution, are calculated and compared with available experimental data.
arXiv: Nuclear Theory, 2020
In recent years, investigations of angular distributions of fragments in neutron-induced nuclear fission have been extended to intermediate energies, up to 200 MeV, as well as to a wide range of target isotopes. Using as an example the latest data obtained by our group for the reaction 237-Np(n,f), we discuss the specific features of fission fragment angular distribution and present a method for their simulation based on the code TALYS. It is shown that a simplified model reasonably describes energy dependence of the angular distribution in the whole range 1-200 MeV. The ways to improve the model are discussed along with the possibilities to use it for obtaining new information on fission and pre-equilibrium processes in neutron-nucleus interaction. We consider also the relevant problems of describing fission fragment angular distributions.
Experimental studies of nuclear fission dynamics near the scission point
Bulletin of the Russian Academy of Sciences: Physics, 2007
Conditions for formation of angular and energy distributions of light particles emitted in ternary fission of 233, 235 U , 239 Pu , and 245 Cm nuclei induced by cold polarized neutrons have been studied in the course of investigating T -odd asymmetry in emission of these particles with respect to the plane formed by the fission axis and the polarization axis of the fissioning nucleus. The results obtained lead to the conclusion that in ternary fission charged particles are emitted by the fissioning nuclear system rotating around the polarization direction.
Fission dynamics in the proton induced fission of heavy nuclei
Nuclear Physics A, 2004
Multi-parameter correlation study of the reaction 242Pu(p, f) at E,, = 13, 20 and 55 MeV has been carried out. Fission fragment mass and kinetic energy distributions and the double differential neutron spectra have been measured. It was observed that the two-humped shape of mass distributions prevailed up to highest proton energy. Manifestation of the nuclear shell 2 = 28 near fragment mass Af, = 70 has been detected. The experimental results were analyzed in the framework of a time-dependent statistical model with inclusion of nuclear friction effects in the fission process. The multi-parameter correlation study of the reaction During the past two decades the number and the scope of studies on fission dynamics involving heavy ion reactions have increased significantly [l]. Nevertheless, the use of light projectiles for investigation of fission dynamics of heavy compound nuclei retains at least two important advantages: (i) the contribution of the fast fission will be excluded due to small angular momenta, and (ii) it is possible to study the fission dynamics at the compound nuclei excitation energy below 50 MeV where the fusion-fission heavy ion reaction cross sections are small. The contradictions between the pre-and postscission neutron multiplicities measured in the heavy ion reactions and with light particle projectiles were already discussed [2] but data about the pre-and post-scission neutron multiplicities from light particle induced fission remain scarce and are mainly at excitation energies below 30 MeV. The other important aspects of fission dynamics are the interplay *email rubchen@phys.jyu.fi 0375-9474/$ ~ see front matter 0 2004 Elsevier B.V. All rights reserved
Fission induced by nucleons at intermediate energies
Nuclear Physics A 933, 43, 2015
Monte Carlo calculations of fission of actinides and pre-actinides induced by protons and neutrons in the energy range from 100 MeV to 1 GeV are carried out by means of a recent version of the Liège Intranuclear Cascade Model, INCL++, coupled with two different evaporation-fission codes, GEMINI++ and ABLA07. In order to reproduce experimental fission cross sections, model parameters are usually adjusted on available (p, f ) cross sections and used to predict (n, f ) cross sections for the same isotopes. arXiv:1409.4885v1 [nucl-th] 17 Sep 2014 Important applications of intermediate energy fission are energy production with accelerator driven systems [1], radioactive waste transmutation[2]