scholarly journals Measurement of the energy dependence of prompt fission neutron emission from /sup 233/U, /sup 235/U, and /sup 239/Pu for E = 0. 0005 to 10 MeV relative to emission from spontaneous fission of /sup 252/Cf

1985 ◽  
Author(s):  
R. Gwin ◽  
R.R. Spencer ◽  
R.W. Ingle
Keyword(s):  
Energy Dependence ◽  
Spontaneous Fission ◽  
Neutron Emission ◽  
Fission Neutron ◽  
Prompt Fission ◽  
Prompt Fission Neutron

scholarly journals Observations of poorly-known features of the 239Pu and 235U prompt fission neutron spectra

2020 ◽  
Vol 239 ◽  
pp. 05010
Author(s):  
Keegan J. Kelly ◽  
Jaime A. Gomez ◽  
John M. O'Donnell ◽  
Matthew Devlin ◽  
Robert C. Haight ◽  
...  
Keyword(s):  
Experimental Data ◽  
Neutron Spectrum ◽  
Neutron Emission ◽  
National Laboratory ◽  
Nuclear Data ◽  
Fission Neutron ◽  
Fission Neutron Spectrum ◽  
Wide Range ◽  
Prompt Fission ◽  
Prompt Fission Neutron

Prompt fission neutron spectrum (PFNS) evaluations use provide nuclear data for the PFNS across a wide range of incident and outgoing neutron energies. However, experimental data underlying the evaluation are sparse, inconsistent, and incomplete with respect to the desired incident and outgoing energy coverage. As such, evaluations sometimes predict features of the PFNS, such those relating to multi-chance fission and pre-equilibrium pre-fission neutron emission, without any experimental validation. The Chi-Nu experiment at Los Alamos National Laboratory has recently obtained high-precision results for the 239Pu and 235U PFNS which, for the first time in both cases, have shed light on multi-chance fission and pre-equilibrium contributions to the observed fission neutron spectrum. In addition to providing the first experimental data on some of these fission properties, the angular coverage of the Chi-Nu experiment allows for the extraction of angular distributions of pre-equilibrium pre-fission neutrons. PFNS results of multi-chance fission and pre-equilibrium pre-fission neutron emission are discussed in this proceedings in terms of the observed neutron spectrum and the average PFNS energies.

scholarly journals Prompt Fission Neutron Investigation in 235U(nth,f) and 252Cf(sf) Reactions

2019 ◽  
Vol 211 ◽  
pp. 04003 ◽  
Author(s):  
Shakir Zeynalov ◽  
Pavel Sedyshev ◽  
Valery Shvetsov ◽  
Olga Sidorova
Keyword(s):  
Kinetic Energy ◽  
Fission Fragment ◽  
Ionization Chamber ◽  
Neutron Emission ◽  
Digital Signal ◽  
Fission Neutron ◽  
Sampling Frequency ◽  
Prompt Neutron ◽  
Prompt Fission ◽  
Prompt Fission Neutron

The prompt neutron emission in thermal neutron induced fission of 235U and spontaneous fission of 252Cf was investigated by using digital signal electronics. The goal was to check a new revised data analysis software with fission fragment (FF) kinetic energy corrections after prompt fission neutron (PFN) emission. The revised software was used to reanalyze old data measured in EC-JRC-IRMM, where 252Cf(sf) reaction was investigated. Both measurements were done using similar twin Frisch grid ionization chamber for fission fragment detection with equivalent NE213 fast neutron detector. About 0.5*106 FF with PFN coincidences have been analyzed in both measurements. The fission fragment kinetic energy, mass and angular distribution were investigated along with prompt neutron time of flight and pulse shape analysis using a six channel synchronous waveform digitizer (WFD) with sampling frequency of 250 MHz and 12 bit resolution in the 235U(nth,f) reaction. Similar WFD with sampling frequency of 100 MHz was used for PFN investigation in 252Cf(sf) reaction. These two experiments were considered as a reference for further investigations with a new setup composed of position sensitive ionization chamber to detect FF and an array of 32 liquid scintillators recently constructed in Dubna to detect neutrons.

The systematics of the (n, 2n) cross section (the Csikai–Peto effect)

1977 ◽  
Vol 55 (24) ◽  
pp. 2145-2149
Author(s):  
H. L. Pai ◽  
D. G. Andrews
Keyword(s):  
Neutron Emission ◽  
Underlying Mechanism ◽  
Fission Neutron ◽  
Work Related ◽  
Statistical Model Calculation ◽  
The Subject ◽  
Future Work ◽  
Prompt Fission ◽  
Prompt Fission Neutron ◽  
Method Agreement

The Csikai–Peto effect has been re-evaluated by a statistical-model calculation method. Agreement and disagreement of the theory with the Csikai–Peto effect are analyzed in the light of the possible underlying mechanism, which in some aspects is close to that of prompt fission neutron emission. Future work related to the subject is proposed.

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