Fission-fragment yields and prompt-neutron multiplicity for Coulomb-induced fission of U234,235 and Np237,238

2021 ◽  
Vol 104 (4) ◽  
Author(s):  
J.-F. Martin ◽  
J. Taïeb ◽  
G. Boutoux ◽  
A. Chatillon ◽  
T. Gorbinet ◽  
...  
Keyword(s):  
Fission Fragment ◽  
Neutron Multiplicity ◽  
Prompt Neutron ◽  
Induced Fission

Sensitivity of Prompt Neutron Multiplicity to Fission Fragment Characteristics

2015 ◽  
Vol 181 (3) ◽  
pp. 289-301 ◽  
Author(s):  
A. Tudora ◽  
F.-J. Hambsch ◽  
S. Oberstedt ◽  
G. Giubega ◽  
I. Visan
Keyword(s):  
Fission Fragment ◽  
Neutron Multiplicity ◽  
Prompt Neutron

scholarly journals Calculation of the fission observables in the resolved resonance energy region of the 235U(n,f) reaction

2020 ◽  
Vol 239 ◽  
pp. 05002
Author(s):  
Olivier Serot ◽  
Olivier Litaize ◽  
Abdelhazize Chebboubi
Keyword(s):  
Kinetic Energy ◽  
Fission Fragment ◽  
Energy Region ◽  
Resonance Energy ◽  
Neutron Multiplicity ◽  
Prompt Neutron ◽  
Incident Neutron ◽  
Monte Carlo Code ◽  
Fission Fragments ◽  
Free Parameters

Measurement of the fission fragments in coincidence with the emitted prompt neutrons was undertaken recently, at JRC-Geel institute, for the 235U(n,f) reaction in the resolved resonance energy region, up to 160 eV incident neutron energy. From this experimental work, fluctuations of several fission observables (mass yields, average total kinetic energy T̅K̅E̅, average prompt neutron multiplicity v̅P) were clearly observed. In the present work, these experimental pre-neutron fission fragment mass and kinetic energy distributions were used as input data for the FIFRELIN Monte Carlo code. By adopting the Hauser-Feshbach statistical model, the code simulates the de-excitation of the fission fragments. Four free parameters are available in the code: two of them (called RTmin and RTmax) govern at the scission point the sharing of the total available excitation energy between the two nascent fission fragments, while the two others (called σL and σH) assign the initial fission fragment spins. In this way, fission observables (prompt particles energy spectra and multiplicities, delayed neutrons multiplicity,. . . ) and correlations between them can be predicted and investigated. Here, these four free parameters were tuned in order to reproduce the average prompt neutron multiplicity at the resonance En=19.23 eV, resonance for which the experimental statistical uncertainty on v̅P is the lowest one. Then, the calculations were perfomed for all resonances by keeping the same set of free parameters. We show that the calculated fluctuations of v̅P in the resonances can rather be well reproduced by considering only the fluctuations of the pre-neutron mass yields and kinetic energy. In addition, from our calculation procedure, other fission observables fluctuations can also be predicted.

scholarly journals Monte Carlo simulation of the measurement by the 2E technique of the average prompt neutron multiplicity as a function of the mass of fragments from thermal neutron-induced fission of 239Pu

2021 ◽  
Vol 68 (1 Jan-Feb) ◽  
Author(s):  
Modesto Montoya ◽  
Oliver Páucar ◽  
A. Obregón ◽  
A. Aponte
Keyword(s):  
Monte Carlo ◽  
Standard Deviation ◽  
Kinetic Energy ◽  
Thermal Neutron ◽  
Neutron Multiplicity ◽  
Total Kinetic Energy ◽  
Prompt Neutron ◽  
Fragment Mass ◽  
Induced Fission ◽  
Experimental Values

Using a Monte Carlo method, we simulate the measurement, by the 2E technique, of the average prompt neutron multiplicity as a function of the mass of fragments from the thermal neutron-induced fission of 239Pu. The input data for the simulation, associated with the primary fragment mass (A), consist of the yield (Y), the distribution of the total kinetic energy characterized by its average ((TKE) ̅) and its standard deviation (σ_TKE), the average prompt neutron multiplicity (ν ̅_s, a sawtooth approach of experimental data), and the slope of neutron multiplicity against total kinetic energy (dν_s/d<TKE>). The output data, associated with the simulated as the fragment mass measured by the 2E technique (µ), consist of the yield (y), the distribution of the total kinetic energy characterized by its average ((tke) ̅) and its standard deviation (σ_tke), and the average prompt neutron multiplicity (ν ̅_µ). In the mass regions A≈115 and A>150, ν ̅_µ is higher than ν ̅_s. This result suggests that, in those mass regions, the 2E experimental values associated with the average neutron multiplicity are overestimated, referred to the corresponding to the primary fragments.

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