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Title: Prompt fission product yields in the U 238 ( n , f ) reaction

Abstract

Background: Significant yield discrepancies (500-600%) were reported recently between experi- mental results and predictions (from the GEF model) and evaluations (from the JEFF-3.1.1 and ENDF/B-VII.1 libraries) for Mo and Sn fission-fragment yields in fast-neutron induced reactions on 238U using γ-γ-γ coincidence spectroscopy. The model/evaluations also predict Mo and Sn fragments that are on average ~1 to 2 neutrons richer than the experimental results. Purpose: γ-γ-γ coincidence spectroscopy favors detection of higher-multiplicity γ-ray cascades. An alternative approach is determining the fragment yields using single-γ-ray spectroscopy, as it was attempted here for selected cases where it was feasible. Advantages/drawbacks in both approaches need to be understood and potential systematic errors in the experimental results should be addressed using theoretical models. Methods: Fast neutrons from the LANSCE WNR facility were used to induce fission on 238U. The emitted γ rays were measured with the GEANIE spectrometer. Results: The yield of selected even-even fission fragments was determined. The selection was based on the ability to reliably determine excitation functions for the detected γ rays. Conclusions: Our single-γ-ray results provide better agreement between experiment and predictions/evaluations.

Authors:
ORCiD logo [1];  [2]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [3]; ORCiD logo [1];  [4]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Saclay (France); Univ. Paris-Saclay, Gif-sur-Yvette (France). Den-SERMA
  3. Autorité de Sûreté Nucléaire, Montrouge (France)
  4. Alternative Energies and Atomic Energy Commission (CEA), Arpajon (France)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1495151
Alternate Identifier(s):
OSTI ID: 1493512
Report Number(s):
LA-UR-18-23000
Journal ID: ISSN 2469-9985; PRVCAN
Grant/Contract Number:  
89233218CNA000001; W-7405-ENG-36; AC52-06NA25396; W-7405-ENG-48; AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 99; Journal Issue: 2; Journal ID: ISSN 2469-9985
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS

Citation Formats

Fotiadis, Nikolaos, Casoli, Pierre, Jaffke, Patrick John, Devlin, Matthew James, Nelson, Ronald Owen, Granier, Thierry, Talou, Patrick, and Ethvignot, Thierry. Prompt fission product yields in the U238(n,f) reaction. United States: N. p., 2019. Web. doi:10.1103/PhysRevC.99.024606.
Fotiadis, Nikolaos, Casoli, Pierre, Jaffke, Patrick John, Devlin, Matthew James, Nelson, Ronald Owen, Granier, Thierry, Talou, Patrick, & Ethvignot, Thierry. Prompt fission product yields in the U238(n,f) reaction. United States. doi:10.1103/PhysRevC.99.024606.
Fotiadis, Nikolaos, Casoli, Pierre, Jaffke, Patrick John, Devlin, Matthew James, Nelson, Ronald Owen, Granier, Thierry, Talou, Patrick, and Ethvignot, Thierry. Tue . "Prompt fission product yields in the U238(n,f) reaction". United States. doi:10.1103/PhysRevC.99.024606.
@article{osti_1495151,
title = {Prompt fission product yields in the U238(n,f) reaction},
author = {Fotiadis, Nikolaos and Casoli, Pierre and Jaffke, Patrick John and Devlin, Matthew James and Nelson, Ronald Owen and Granier, Thierry and Talou, Patrick and Ethvignot, Thierry},
abstractNote = {Background: Significant yield discrepancies (500-600%) were reported recently between experi- mental results and predictions (from the GEF model) and evaluations (from the JEFF-3.1.1 and ENDF/B-VII.1 libraries) for Mo and Sn fission-fragment yields in fast-neutron induced reactions on 238U using γ-γ-γ coincidence spectroscopy. The model/evaluations also predict Mo and Sn fragments that are on average ~1 to 2 neutrons richer than the experimental results. Purpose: γ-γ-γ coincidence spectroscopy favors detection of higher-multiplicity γ-ray cascades. An alternative approach is determining the fragment yields using single-γ-ray spectroscopy, as it was attempted here for selected cases where it was feasible. Advantages/drawbacks in both approaches need to be understood and potential systematic errors in the experimental results should be addressed using theoretical models. Methods: Fast neutrons from the LANSCE WNR facility were used to induce fission on 238U. The emitted γ rays were measured with the GEANIE spectrometer. Results: The yield of selected even-even fission fragments was determined. The selection was based on the ability to reliably determine excitation functions for the detected γ rays. Conclusions: Our single-γ-ray results provide better agreement between experiment and predictions/evaluations.},
doi = {10.1103/PhysRevC.99.024606},
journal = {Physical Review C},
number = 2,
volume = 99,
place = {United States},
year = {2019},
month = {2}
}

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