Distributions for Excitation Energy and Kinetic Energy in Nuclear Fission

2005 ◽  
Author(s):  
Herbert R. Faust
Keyword(s):  
Kinetic Energy ◽  
Excitation Energy ◽  
Nuclear Fission

The excitation energy of fragments in nuclear fission

Atomic Energy ◽  
1960 ◽  
Vol 6 (3) ◽  
pp. 184-189
Author(s):  
B. T. Geilikman
Keyword(s):  
Excitation Energy ◽  
Nuclear Fission

scholarly journals Study of High-Energy Fission in Inverse Kinematics

2019 ◽  
Vol 223 ◽  
pp. 01037
Author(s):  
G. Mantovani ◽  
D. Ramos ◽  
M. Caamaño ◽  
A. Lemasson ◽  
M. Rejmund ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Excitation Energy ◽  
Shell Structure ◽  
Inverse Kinematics ◽  
High Energy ◽  
Total Kinetic Energy ◽  
High Excitation Energy ◽  
High Excitation ◽  
Shell Effects

Fission at low excitation energy, is a process in which both macroscopic and microscopic aspects are involved. Some features in the total kinetic energy and in the N/Z distributions of the fragments, commonly associated with shell effects, came out in a series of recent experiments with high excitation energy fusionfission reactions in inverse kinematics. In the latest experiment of this campaign, a study of high-energy fission and quasi-fission between a 238U beam and a series of light targets was carried out by using the aforementioned technique, in order to probe the role of the shell structure in these processes.

scholarly journals Impact of nuclear inertia momenta on fission observables

2018 ◽  
Vol 193 ◽  
pp. 01004
Author(s):  
P. Tamagno ◽  
O. Litaize
Keyword(s):  
Rigid Body ◽  
Excitation Energy ◽  
Nuclear Fission ◽  
Particle Model ◽  
Rotational Inertia ◽  
Neutron Fission ◽  
Fission Fragments ◽  
Rigid Body Model ◽  
Two Parameters ◽  
The Impact

Fission is probably the nuclear process the less accurately described with current models because it involves dynamics of nuclear matter with strongly coupled manybody interactions. It is thus diffcult to find models that are strongly rooted in good physics, accurate enough to reproduce target observables and that can describe many of the nuclear fission observables in a consistent way. One of the most comprehensive current modeling of the fission process relies on the fission sampling and Monte-Carlo de-excitation of the fission fragments. This model is implemented for instance in the FIFRELIN code. In this model fission fragments and their state are first sampled from pre-neutron fission yields, angular momentum distribution and excitation energy repartition law then the decay of both initial fragments is simulated. This modeling provides many observables: prompt neutron and gamma fission spectra, multiplicities and also fine decompositions: number of neutrons emitted as a function of the fragment mass, spectra per fragments, etc. This model relies on nuclear structure databases and on several basic nuclear models describing for instance gamma strength functions or level densities. Additionally some free parameters are still to be determined, namely two parameters describing the excitation energy repartition law, the spin cutoff of the heavy and light fragments and a rescaling parameter for the rotational inertia momentum of the fragments with respect of the rigid-body model. In the present work we investigate the impact of this latter parameter. For this we mainly substitute the corrected rigid-body value by a quantity obtained from a microscopic description of the fission fragment. The independent-particle model recently implemented in the CONRAD code is used to provide nucleonic wave functions that are required to compute inertia momenta with an Inglis-Belyaev cranking model. The impact of this substitution is analyzed on different fission observables provided by the FIFRELIN code.

scholarly journals Fission fragment yields and total kinetic energy release in neutron-induced fission of235,238U,and239Pu

2018 ◽  
Vol 169 ◽  
pp. 00024 ◽  
Author(s):  
F. Tovesson ◽  
D. Duke ◽  
V. Geppert-Kleinrath ◽  
B. Manning ◽  
D. Mayorov ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Kinetic Energy Release ◽  
Nuclear Fission ◽  
Total Kinetic Energy ◽  
Experimental Techniques ◽  
Science Center ◽  
Fission Process ◽  
Induced Fission ◽  
Time Projection ◽  
Energy Dependent

Different aspects of the nuclear fission process have been studied at Los Alamos Neutron Science Center (LANSCE) using various instruments and experimental techniques. Properties of the fragments emitted in fission have been investigated using Frisch-grid ionization chambers, a Time Projection Chamber (TPC), and the SPIDER instrument which employs the 2v-2E method. These instruments and experimental techniques have been used to determine fission product mass yields, the energy dependent total kinetic energy (TKE) release, and anisotropy in neutron-induced fission of U-235, U-238 and Pu-239.

TIME-OF-FLIGHT FISSION STUDIES ON U233, U235 AND Pu239

1962 ◽  
Vol 40 (11) ◽  
pp. 1626-1663 ◽  
Author(s):  
J. C. D. Milton ◽  
J. S. Fraser
Keyword(s):  
Fine Structure ◽  
Kinetic Energy ◽  
Excitation Energy ◽  
Thermal Neutron ◽  
Time Of Flight ◽  
Neutron Fission ◽  
Thermal Neutron Fission ◽  
The Mean ◽  
New Feature ◽  
Symmetric Fission

The prompt mass and kinetic energy distributions resulting from the thermal neutron fission of U233, U235, and Pu239 have been reinvestigated using time-of-flight methods to measure simultaneously the velocities of the fragment pairs. A new feature shown by the present work is the existence of fine structure in the prompt mass yields. This fine structure is most pronounced at high total kinetic energies where the fragments have little excitation energy and may be associated with irregularities in the energy release as a function of mass. The fine structure is most noticeable in U235 and least in Pu239; the fragments of U235 have the lowest average excitation and those of Pu239, the highest. Another feature, which is confirmed by this work, is the large drop in total kinetic energy when the fragments are near symmetry. This decrease is about 35 Mev and is consistent either with a picture in which the nucleus with 50 protons is especially preferred or with one in which fragments at symmetric fission have an abnormally high excitation energy and a consequent large number of neutrons. The mean kinetic energies for thermal neutron fission of U233, U235, and Pu239 were found to be 167.6, 168.3, and 175.0 Mev with an error of ± 1.7 Mev.

scholarly journals The 4-dimensional Langevin approach to low energy nuclear fission

2018 ◽  
Vol 169 ◽  
pp. 00005
Author(s):  
F.A. Ivanyuk ◽  
C. Ishizuka ◽  
M.D. Usang ◽  
S. Chiba
Keyword(s):  
Excitation Energy ◽  
Mass Number ◽  
Nuclear Fission ◽  
Deformation Energy ◽  
Low Energy ◽  
Tooth Structure ◽  
Fission Fragments ◽  
Langevin Approach ◽  
Intrinsic Excitation ◽  
Mother Nucleus

We applied the four-dimensional Langevin approach to the description of fission of 235U by neutrons and calculated the dependence of the excitation energy of fission fragments on their mass number. For this we have fitted the compact just-before-scission configuration obtained by the Langevin calculations by the two separated fragments and calculated the intrinsic excitation and the deformation energy of each fragment accurately taking into account the shell and pairing effects and their dependence on the temperature and mass of the fragments. For the sharing of energy between the fission fragments we have used the simplest and most reliable assumption - the temperature of each fragment immediately after the neck rupture is the same as the temperature of mother nucleus just before scission. The calculated excitation energy of fission fragments clearly demonstrates the saw-tooth structure in the dependence on fragment mass number.

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