DYNAMICAL SIMULATION OF FISSION FRAGMENTS AVERAGE KINETIC ENERGY IN HEAVY-ION FUSION–FISSION REACTIONS

2011 ◽  
Vol 26 (13) ◽  
pp. 975-985 ◽  
Author(s):  
M. R. PAHLAVANI ◽  
D. NADERI ◽  
S. M. MIRFATHI
Keyword(s):  
Kinetic Energy ◽  
Three Dimensional ◽  
Heavy Ion ◽  
Langevin Equations ◽  
Average Kinetic Energy ◽  
Mass Asymmetry ◽  
Fission Fragments ◽  
Neck Thickness ◽  
Dynamical Parameters ◽  
Heavy Ion Fusion

Monte Carlo simulation based on the three-dimensional Langevin equations and one-body dissipation mechanism has been applied to highly excited compound nucleus to investigate the kinetic energy distribution of fission fragments. The effect of center to center distance between nascent fragments and other dynamical parameters (elongation, neck thickness and mass asymmetry) on average kinetic energy of fragments also studied. Finally, obtained results using this approach are compared with earlier theoretical and experimental data for a few typical systems.

DYNAMICAL SIMULATION OF EMISSION ANGLE DEPENDENCE OF FRAGMENTS SPIN IN HEAVY ION FUSION–FISSION REACTIONS

2010 ◽  
Vol 19 (07) ◽  
pp. 1451-1461 ◽  
Author(s):  
M. R. PAHLAVANI ◽  
D. NADERI ◽  
S. M. MIRFATHI
Keyword(s):  
Experimental Data ◽  
Heavy Ion ◽  
Emission Angle ◽  
Fission Reactions ◽  
Angle Dependence ◽  
Dynamical Simulation ◽  
Deformation Parameters ◽  
Average Spin ◽  
Neck Thickness ◽  
Heavy Ion Fusion

In this paper, a formalism consisting of multi-dimensional Langevin equation (LE) and Scission point Transition State Model (SCTSM) have been applied to study the angle dependence of fragment's average spin for 16 O + 209 Bi and 16 O + 232 Th systems. The influence of asymmetry and deformation parameters, neck thickness of compound nucleus and pre-scission neutron multiplicity on the fragment's average spin is discussed. Results obtained using this approach are in better agreement with the experimental data as compared with the SCTSM.

scholarly journals Neutron excess dependence of fusion barrier parameters

2019 ◽  
Vol 11 ◽  
Author(s):  
N. G. Nicolis
Keyword(s):  
Barrier Height ◽  
Potential Application ◽  
Heavy Ion ◽  
Degree Of Freedom ◽  
Entrance Channel ◽  
Neutron Excess ◽  
Fusion Barrier ◽  
Mass Asymmetry ◽  
Heavy Ion Fusion

The neutron excess dependence of heavy ion fusion barrier parameters is investigated, guided by predictions of different heavy ion potentials. We develop parametrizations for the fusion barrier height and radius which explicitly involve the entrance channel mass asymmetry and neutron excess of the projectile and target. The developed expressions reproduce theoretical barrier parameters within 0.2%, which represents a big improvement over previous parametrizations. Furthermore, they provide a means to assess the importance of the neutron excess degree of freedom implied by each potential. Application of these expressions to systematics of experimental barrier parameters will be discussed.

Study of fission time and prescission neutron multiplicity using four-dimensional Langevin equations

2014 ◽  
Vol 23 (12) ◽  
pp. 1450087 ◽  
Author(s):  
D. Naderi
Keyword(s):  
Stochastic Dynamics ◽  
Stochastic Approach ◽  
Degree Of Freedom ◽  
Neutron Multiplicity ◽  
Langevin Equations ◽  
Orientation Degree ◽  
Four Dimensions ◽  
Dissipation Coefficient ◽  
Mass Asymmetry ◽  
Neck Thickness

In this paper, four-dimensional stochastic approach is applied on dynamics of fission process to calculate mean fission time and prescission neutron multiplicity. Elongation, neck thickness, mass asymmetry and orientation degree of freedom (K-coordinate) are four dimensions in dynamical calculations. In order to investigate the influence of the dissipation coefficient of K-coordinate, the stochastic dynamics of the orientation degree of freedom using nonconstant dissipation coefficient was studied. Calculations were done for the 16 O +208 Pb and 16 O +232 Th reactions. Obtained results were compared with a constant dissipation coefficient (γK = 0.077( MeVzs )-1/2). The mean fission time and prescission neutron multiplicity for nonconstant dissipation case were lower than for the constant one.

scholarly journals δf simulation studies of the ion–electron two-stream instability in heavy ion fusion beams

2003 ◽  
Vol 21 (1) ◽  
pp. 21-26 ◽  
Author(s):  
HONG QIN ◽  
RONALD C. DAVIDSON ◽  
EDWARD A. STARTSEV ◽  
W. WEI-LI LEE
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Longitudinal Direction ◽  
Simulation Method ◽  
Heavy Ion ◽  
Particle Simulation ◽  
Linear Growth Rate ◽  
Momentum Spread ◽  
Heavy Ion Fusion ◽  
Stream Instability

Ion–electron two-stream instabilities in high intensity heavy ion fusion beams, described self-consistently by the nonlinear Vlasov–Maxwell equations, are studied using a three-dimensional multispecies perturbative particle simulation method. Large-scale parallel particle simulations are carried out using the recently developed Beam Equilibrium, Stability, and Transport (BEST) code. For a parameter regime characteristic of heavy ion fusion drivers, simulation results show that the most unstable mode of the ion–electron two-stream instability has a dipole-mode structure, and the linear growth rate decreases with increasing axial momentum spread of the beam particles due to Landau damping by the axial momentum spread of the beam ions in the longitudinal direction.

scholarly journals Particle-in-cell simulations of the dynamic aperture of the HCX

2002 ◽  
Vol 20 (4) ◽  
pp. 577-579 ◽  
Author(s):  
C.M. CELATA ◽  
D.P. GROTE ◽  
I. HABER
Keyword(s):  
National Laboratory ◽  
Three Dimensional ◽  
Heavy Ion ◽  
High Current ◽  
Current Experiment ◽  
Particle Loss ◽  
Particle In Cell ◽  
Dynamic Aperture ◽  
Heavy Ion Fusion ◽  
Three Dimensional Simulations

The Heavy Ion Fusion Virtual National Laboratory High Current Experiment (HCX) is exploring transport issues such as dynamic aperture, effects of quadrupole rotation, and the effects on the beam of nonideal distribution function, mismatch, and electrons, using one driver-scale 0.2 μC/m, 2–10 μs coasting K+ beam. Two- and three-dimensional simulations are being done, using the particle-in-cell code WARP to study these phenomena. We present results which predict that the dynamic aperture in the electrostatic focusing transport section will be set by particle loss.

Effect of the entrance channel mass asymmetry on the limitation of light heavy-ion fusion cross sections

1990 ◽  
Vol 42 (1) ◽  
pp. 354-362 ◽  
Author(s):  
R. M. Anjos ◽  
V. Guimares ◽  
N. Added ◽  
N. Carlin Filho ◽  
M. M. Coimbra ◽  
...  
Keyword(s):  
Cross Sections ◽  
Heavy Ion ◽  
Entrance Channel ◽  
Mass Asymmetry ◽  
Heavy Ion Fusion

scholarly journals Fission observables from 4D Langevin calculations with macroscopic transport coefficients

2018 ◽  
Vol 169 ◽  
pp. 00027 ◽  
Author(s):  
Mark D. Usang ◽  
Fedir A. Ivanyuk ◽  
Chikako Ishizuka ◽  
Satoshi Chiba ◽  
Joachim A. Maruhn
Keyword(s):  
Kinetic Energy ◽  
Transport Coefficients ◽  
Considerable Improvement ◽  
The Other ◽  
Total Kinetic Energy ◽  
Langevin Equations ◽  
Preliminary Results ◽  
Fission Fragments ◽  
Other Hand ◽  
The Moment

We have extended the Langevin equations to 4 dimensions (4D) by allowing the independent deformation for the left (δ1) and right fragments (δ2) of the fissioning nucleus. At the moment we are only able to use them in conjunction with the macroscopic transport coefficients. Nevertheless, we can see a considerable improvement in the preliminary results for the fission observables, especially those related to the total kinetic energy (TKE) of fission fragments. By plotting the TKE distributions we have revealed the super-long fission modes in 236U and super-short fission modes in 257Fm. By plotting the distribution of δ against the fragment’s TKE we have noted a correlation between the values of δ and Brosa’s fission modes. We have found that the standard fission modes correspond to prolate tips of the light fragments while the complementary heavy fragments have oblate fission tips. On the other hand, if both fragments were prolate at the tips, we get super-long fission modes. If both fragments were oblate at the tips, we get super-short fission modes.

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