The LANL/LLNL Program to Measure Prompt Fission Neutron Spectra at LANSCE

ORAL

Abstract

Accurate data on the spectrum of neutrons emitted in neutron-induced fission are needed for applications and for a better understanding of the fission process. At LANSCE we have made important progress in understanding systematic uncertainties and in obtaining data for $^{235}$U on the low-energy part of the prompt fission neutron spectra (PFNS), a particularly difficult region because down-scattered neutrons go in this direction. We use a double time-of-flight technique to determine energies of incoming and outgoing neutrons. With data acquisition via waveform digitizers, accidental coincidences between fission chamber and neutron detector are measured to high statistical accuracy and then subtracted from measured events. Monte Carlo simulations with high performance computers have proven to be essential in the design to minimize neutron scattering and in calculating detector response. Results from one of three approaches to analyzing the data will be presented.

*This work is funded by the US Department of Energy, National Nuclear Security Administration and Office of Nuclear Physics.

–

Authors

  • Robert Haight

    • Los Alamos National Laboratory

  • C.Y. Wu

    • Lawrence Livermore National Laboratory

  • Hye Young Lee

    • Los Alamos Natl Lab
    • Los Alamos National Laboratory

  • Terry Taddeucci

    • Los Alamos National Laboratory

  • Shea Mosby

    • Los Alamos National Laboratory
    • LANSCE P-27
    • LANL

  • John M. O'Donnell

    • Los Alamos National Laboratory
    • LANL

  • Nikolaos Fotiades

    • LANL
    • Los Alamos National Laboratory

  • Mattew Devlin

    • LANL
    • Los Alamos National Laboratory

  • John L. Ullmann

    • Los Alamos National Laboratory
    • LANL

  • Ron Nelson

    • LANL
    • Los Alamos National Laboratory

  • Stephen Wender

    • Los Alamos National Laboratory

  • Morgan White

    • Los Alamos National Laboratory

  • Clell Solomon

    • Los Alamos National Laboratory

  • Denise Neudecker

    • Los Alamos National Laboratory

  • Patrick Talou

    • Los Alamos National Laboratory

  • Michael Rising

    • Los Alamos National Laboratory

  • Brian Bucher

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

  • M.Q. Buckner

    • Lawrence Livermore National Laboratory

  • R.A. Henderson

    • Lawrence Livermore National Laboratory