scholarly journals Investigation of the heavy nuclei fission with anomalously high values of the fission fragments total kinetic energy

2018 ◽  
Vol 169 ◽  
pp. 00011
Author(s):  
Vitaly Khryachkov ◽  
Andrei Goverdovskii ◽  
Vladimir Ketlerov ◽  
Vecheslav Mitrofanov ◽  
Alexei Sergachev
Keyword(s):  
Kinetic Energy ◽  
Compound Nucleus ◽  
Fission Fragment ◽  
Total Kinetic Energy ◽  
Fast Neutrons ◽  
Heavy Nuclei ◽  
Fission Fragments ◽  
Close Analysis ◽  
Fragment Distribution ◽  
Induced Fission

Binary fission of 232Th and 238U induced by fast neutrons were under intent investigation in the IPPE during recent years. These measurements were performed with a twin ionization chamber with Frisch grids. Signals from the detector were digitized for further processing with a specially developed software. It results in information of kinetic energies, masses, directions and Bragg curves of registered fission fragments. Total statistics of a few million fission events were collected during each experiment. It was discovered that for several combinations of fission fragment masses their total kinetic energy was very close to total free energy of the fissioning system. The probability of such fission events for the fast neutron induced fission was found to be much higher than for spontaneous fission of 252Cf and thermal neutron induced fission of 235U. For experiments with 238U target the energy of incident neutrons were 5 MeV and 6.5 MeV. Close analysis of dependence of fission fragment distribution on compound nucleus excitation energy gave us some explanation of the phenomenon. It could be a process in highly excited compound nucleus which leads the fissioning system from the scission point into the fusion valley with high probability.

scholarly journals Three Exit Channels in the Fission of 235U(n, f)

1987 ◽  
Vol 42 (8) ◽  
pp. 786-790 ◽  
Author(s):  
H.-H. Knitter ◽  
F.-J. Hambsch ◽  
C. Budtz-Jørgensen ◽  
J. P. Theobald
Keyword(s):  
Kinetic Energy ◽  
Coordinate System ◽  
Thermal Neutron ◽  
Fission Fragment ◽  
Channel Model ◽  
Total Kinetic Energy ◽  
Fragment Mass ◽  
Theoretical Predictions ◽  
Induced Fission ◽  
Fragment Yield

A formula for the fission fragment yield area in the coordinate system of the fragment total kinetic energy and of the fragment mass is presented. It was deduced along the lines of the multiexit- channel model of fission elaborated by Brosa, Grossmann and Müller. This formula was fitted to the fragment mass-, average total kinetic energy-, and variance distributions of the thermal neutron induced fission of 235U. The obtained parameters are compared with the theoretical predictions. Further improvements of the fragment yield representation are discussed.

scholarly journals Fission-fragment total kinetic energy and mass yields for neutron-induced fission of 235U and 238U with En =200 keV – 30 MeV

2017 ◽  
Vol 146 ◽  
pp. 04042 ◽  
Author(s):  
D.L. Duke ◽  
F. Tovesson ◽  
T. Brys ◽  
V. Geppert-Kleinrath ◽  
F.-J. Hambsch ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Fission Fragment ◽  
Total Kinetic Energy ◽  
Induced Fission

BIMODAL FISSION IN 258FM

1986 ◽  
Vol 01 (06) ◽  
pp. 377-381 ◽  
Author(s):  
K. DEPTA ◽  
J.A. MARUHN ◽  
W. GREINER ◽  
W. SCHEID ◽  
A. SANDULESCU
Keyword(s):  
Kinetic Energy ◽  
Shell Model ◽  
Fission Products ◽  
Degree Of Freedom ◽  
Total Kinetic Energy ◽  
Heavy Nuclei ◽  
Energy Distributions ◽  
Decay Channels ◽  
Symmetric Fission ◽  
Kinetic Energy Distributions

Within the 2-center shell model we present an explanation for the mass and total-kinetic-energy distributions of fission products of very heavy nuclei called “bimodal fission.” For the case of 258 FM we show that the symmetric fission can be described by a 2-dimensional treatment of the elongation and neck degree of freedom. Owing to shell corrections the system fissions via two decay channels that have distinct kinetic energies.

scholarly journals Total Kinetic Energy and Fragment Mass Distribution of Neutron-Induced Fission of U-233

2017 ◽  
Author(s):  
Daniel James Higgins ◽  
Kyle Thomas Schmitt ◽  
Shea Morgan Mosby ◽  
Fredrik Tovesson
Keyword(s):  
Kinetic Energy ◽  
Mass Distribution ◽  
Total Kinetic Energy ◽  
Fragment Mass ◽  
Induced Fission

scholarly journals Microscopic Calculation of Fission Fragment Distributions in Actinides

2020 ◽  
Vol 242 ◽  
pp. 03001
Author(s):  
N. Schunck
Keyword(s):  
Fission Fragment ◽  
Initial Conditions ◽  
Quantum Mechanical ◽  
Incident Neutron ◽  
Incident Neutron Energy ◽  
Fission Fragments ◽  
Microscopic Calculation ◽  
Precise Knowledge ◽  
Quantum Mechanical Description ◽  
Induced Fission

The simulation of independent and cumulative yields requires precise knowledge of the initial conditions of the fission fragments immediately after scission. In this paper, we use a quantum-mechanical description of fission dynamics to extract the initial mass distribution of fission fragments for the neutron-induced fission of the two major actinides 239 Pu and 235 U, both for thermal fission and as a function of the incident neutron energy.

MEASUREMENT OF FISSION FRAGMENT ANISOTROPIES FOR PROTON-INDUCED FISSION OF TWO PRE-ACTINIDE NUCLEI AT SEVERAL ENERGIES

2007 ◽  
Vol 22 (05) ◽  
pp. 1027-1037 ◽  
Author(s):  
S. SOHEYLI ◽  
H. NOSHAD ◽  
M. LAMEHI-RACHTI
Keyword(s):  
Angular Distribution ◽  
Statistical Model ◽  
Cross Sections ◽  
Fission Fragment ◽  
Anomalous Behavior ◽  
Surface Barrier ◽  
Mass Asymmetry ◽  
Fission Fragments ◽  
Induced Fission ◽  
Barrier Detectors

The angular distribution of fission fragments has been measured for proton-induced fission of 197 Au and 209 Bi nuclei at several energies between 25 and 30 MeV using surface-barrier detectors. The measured anisotropies are found to be in agreement with the predictions of the standard saddle-point statistical model. The measured anisotropies for neither of the nuclei show any anomalous behavior as a function of both energy and entrance channel mass asymmetry. The fission cross sections of 197 Au and 209 Bi nuclei were also measured and compared with that of the previous works.

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.

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