Probing nuclear dissipation with first-chance fission probability

2018 ◽  
Vol 97 (1) ◽  
Author(s):  
N. Wang ◽  
W. Ye
Keyword(s):  
Fission Probability ◽  
Nuclear Dissipation

INFLUENCE OF NUCLEAR DISSIPATION ON PRESCISSION NEUTRON MULTIPLICITY, FISSION PROBABILITY AND FISSION TIME FOR COMPOUND NUCLEUS 210Po

2012 ◽  
Vol 21 (01) ◽  
pp. 1250008 ◽  
Author(s):  
H. ESLAMIZADEH
Keyword(s):  
Compound Nucleus ◽  
Stochastic Approach ◽  
Neutron Multiplicity ◽  
Langevin Equations ◽  
Excitation Energies ◽  
One Dimensional ◽  
Reduction Coefficient ◽  
Fission Probability ◽  
Nuclear Dissipation ◽  
Good Agreement

A stochastic approach for fission dynamics based on one-dimensional Langevin equations was applied to investigate the effect of the nuclear dissipation on the prescission neutron multiplicity, fission probability and the fission time for the compound nucleus 210 Po in an intermediate range of excitation energies 30–120 MeV. A modified wall and window dissipation with a reduction coefficient, k s , has been used in the Langevin equations. It was shown that the results of the calculations are in good agreement with the experimental data by using values of k s in the range 0.28 ≤ k s ≤ 0.50.

scholarly journals Comparison of Direct and Adjoint k and α-Eigenfunctions

2021 ◽  
Vol 2 (2) ◽  
pp. 132-151
Author(s):  
Vito Vitali ◽  
Florent Chevallier ◽  
Alexis Jinaphanh ◽  
Andrea Zoia ◽  
Patrick Blaise
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Methods ◽  
Energy Transport ◽  
Distinct Point ◽  
Point Of View ◽  
Critical Systems ◽  
Small Deviations ◽  
Power Iteration ◽  
Continuous Energy ◽  
Fission Probability

Modal expansions based on k-eigenvalues and α-eigenvalues are commonly used in order to investigate the reactor behaviour, each with a distinct point of view: the former is related to fission generations, whereas the latter is related to time. Well-known Monte Carlo methods exist to compute the direct k or α fundamental eigenmodes, based on variants of the power iteration. The possibility of computing adjoint eigenfunctions in continuous-energy transport has been recently implemented and tested in the development version of TRIPOLI-4®, using a modified version of the Iterated Fission Probability (IFP) method for the adjoint α calculation. In this work we present a preliminary comparison of direct and adjoint k and α eigenmodes by Monte Carlo methods, for small deviations from criticality. When the reactor is exactly critical, i.e., for k0 = 1 or equivalently α0 = 0, the fundamental modes of both eigenfunction bases coincide, as expected on physical grounds. However, for non-critical systems the fundamental k and α eigenmodes show significant discrepancies.

FISSION TIME OF α-INDUCED REACTIONS MEASURED BY THE CRYSTAL BLOCKING TECHNIQUE

2010 ◽  
Vol 19 (05n06) ◽  
pp. 1227-1235 ◽  
Author(s):  
V. A. DROZDOV ◽  
D. O. EREMENKO ◽  
O. V. FOTINA ◽  
S. Yu. PLATONOV ◽  
O. A. YUMINOV ◽  
...  
Keyword(s):  
Fission Fragment ◽  
Statistical Approach ◽  
Reliable Information ◽  
Fission Barrier ◽  
Large Set ◽  
Angular Anisotropy ◽  
Excitation Energies ◽  
Shell Effects ◽  
Pu Isotopes ◽  
Nuclear Dissipation

A large set of experimental observables for the 232 Th , 235 U (α, xnf ) reactions has been analyzed within the dynamic-statistical approach with allowance for the nuclear dissipation phenomenon, the double humped structure of fission barrier, and also the temperature damping of shell effects. The energy dependences of the lifetime effect (experimentally measured by the crystal blocking technique) along the corresponding data on the fission fragment angular anisotropy and also fission probabilities of U and Pu isotopes produced in the reactions were chosen for the analysis. Reliable information on the nuclear viscosity at the low excitation energies (< 30 MeV) was obtained.

MODELLING OF DISSIPATION IN NUCLEAR FISSION

2004 ◽  
Vol 13 (01) ◽  
pp. 97-101
Author(s):  
C. SCHMITT ◽  
B. JURADO ◽  
A. R. JUNGHANS ◽  
K.-H. SCHMIDT ◽  
J. BENLLIURE
Keyword(s):  
Experimental Approach ◽  
Nuclear Fission ◽  
Heavy Ion ◽  
Analytical Approximation ◽  
Time Dependent ◽  
Relativistic Energy ◽  
Transient Effects ◽  
Ion Collisions ◽  
Relaxation Effects ◽  
Nuclear Dissipation

Peripheral heavy-ion collisions at relativistic energy are proposed as a new experimental approach dedicated to nuclear dissipation studies and, in particular, to investigate transient effects which are responsible for the inhibition of fission at the beginning of the process. To extract reliable information from the data, an analytical approximation of the time-dependent fission decay width is used in connection with new experimental signatures of relaxation effects.

Nuclear dissipation with residual interactions studied by means of the Mori formalism

1981 ◽  
Vol 299 (3) ◽  
pp. 231-239 ◽  
Author(s):  
E. Werner ◽  
H. S. Wio ◽  
H. Hofmann ◽  
K. Pomorski
Keyword(s):  
Nuclear Dissipation

Inference on fission timescale from neutron multiplicity measurement in18O+184W

2022 ◽  
Author(s):  
Niraj Kumar Rai ◽  
Aman Gandhi ◽  
M T Senthil Kannan ◽  
Sujan Kumar Roy ◽  
Saneesh Nedumbally ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Beam Energy ◽  
Incident Beam ◽  
Fission Process ◽  
Incident Beam Energy ◽  
Neutron Evaporation ◽  
Neutron Multiplicities ◽  
Nuclear Dissipation ◽  
Fission Yields ◽  
Primary Compound

Abstract The pre-scission and post-scission neutron multiplicities are measured for the 18O + 184W reaction in the excitation energy range of 67.23−76.37 MeV. Langevin dynamical calculations are performed to infer the energy dependence of fission decay time in compliance with the measured neutron multiplicities. Different models for nuclear dissipation are employed for this purpose. Fission process is usually expected to be faster at a higher beam energy. However, we found an enhancement in the average fission time as the incident beam energy increases. It happens because a higher excitation energy helps more neutrons to evaporate that eventually stabilizes the system against fission. The competition between fission and neutron evaporation delicately depends on the available excitation energy and it is explained here with the help of the partial fission yields contributed by the different isotopes of the primary compound nucleus.

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