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Title: Bounding the 239Pu(n,f) cross-section

 [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [2];  [1];  [3]
  1. Los Alamos National Laboratory
  2. Argonne National Laboratory
  3. International Atomic Energy Agency
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Resource Relation:
Conference: CW2017 ; 2017-10-02 - 2017-10-06 ; Aix-En-Provence, France
Country of Publication:
United States
Atomic and Nuclear Physics

Citation Formats

Hejnal, Brooke Ellen, Neudecker, Denise, Tovesson, Fredrik, White, Morgan Curtis, Smith, Donald L., Vaughan, Diane Elizabeth, and Capote, Roberto. Bounding the 239Pu(n,f) cross-section. United States: N. p., 2017. Web.
Hejnal, Brooke Ellen, Neudecker, Denise, Tovesson, Fredrik, White, Morgan Curtis, Smith, Donald L., Vaughan, Diane Elizabeth, & Capote, Roberto. Bounding the 239Pu(n,f) cross-section. United States.
Hejnal, Brooke Ellen, Neudecker, Denise, Tovesson, Fredrik, White, Morgan Curtis, Smith, Donald L., Vaughan, Diane Elizabeth, and Capote, Roberto. 2017. "Bounding the 239Pu(n,f) cross-section". United States. doi:.
title = {Bounding the 239Pu(n,f) cross-section},
author = {Hejnal, Brooke Ellen and Neudecker, Denise and Tovesson, Fredrik and White, Morgan Curtis and Smith, Donald L. and Vaughan, Diane Elizabeth and Capote, Roberto},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month =

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  • No abstract provided.
  • Absolute partial {gamma}-ray cross sections for production of discrete {gamma} rays in the {sup 239}Pu(n,2n{gamma}i){sup 238}Pu reaction have been measured. The experiments were performed at LANSCE/WNR on the 60R flight line. Reaction {gamma}-rays were measured using the large-scale Compton-suppressed array of Ge detectors, GEANIE. The motivation for this experiment, an overview of the partial {gamma}-ray cross-section measurement, and an introduction to the main experimental issues will be presented. The energy resolution of the Ge detectors allowed identification of reaction {gamma} rays above the background of sample radioactivity and fission {gamma} rays. The use of planar Ge detectors with their reducedmore » sensitivity to neutron interactions and improved line shape was also important to the success of this experiment. Absolute partial {gamma}-ray cross sections are presented for the 6{sub 1}{sup +} {yields} 4{sub 1}{sup +} member of the ground state rotational band in {sup 238}Pu, together with miscellaneous other {gamma}-ray partial cross sections. The n,2n reaction cross section shape and magnitude as a function of neutron energy was extracted from these partial cross sections using nuclear modeling (enhanced Hauser-Feshbach) to relate partial {gamma}-ray cross sections to the n,2n cross section. The critical nuclear modeling issue is the ratio of a partial cross section to the reaction channel cross section, and not the prediction of the absolute magnitude.« less
  • The average total neutron cross sections of {sup 233}U, {sup 235}U, and {sup 239}Pu were obtained from transmission measurements in the unresolved resonance region up to several hundred keV neutron energy. The method used for the calculation of the self-shielding effect is described. A statistical model analysis of the results was performed and the s-, p- and d-wave neutron strength functions were obtained.
  • High precision measurements of the {sup 239}Pu(n,f) cross section have been identified as important for the Global Nuclear Energy Partnership (GNEP) and other programs. Currently the uncertainty on this cross section is of the order 2-3% for neutron energies below 14 MeV and the goal is to reduce this to less than 1%. The Time Projection Chamber (TPC) has been identified as a possible tool to make this high precision measurement.
  • The {sup 239}Pu(n,2n) and the {sup 235}U(n,2n) cross section are estimated by applying unitarity in several approaches: a subtraction method and also by using a ratio approach that relates the above cross sections to the {sup 238}U(n,2n) cross section and the {sup 239}Pu(n,2n) cross section to the {sup 235}U(n,2n) cross section, respectively. Also, a self-consistent, simultaneous analysis of the cross section data of four nuclei, {sup 239}Pu, {sup 235}U, {sup 238}U and {sup 232}Th, was undertaken to evaluate the {sup 239}Pu(n,2n) cross section at 11 MeV.