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Title: Neutron-neutron angular correlations in spontaneous fission of Cf 252 and Pu 240

Abstract

Background: Angular anisotropy has been observed between prompt neutrons emitted during the fission process. Such an anisotropy arises because the emitted neutrons are boosted along the direction of the parent fragment. Purpose: To measure the neutron-neutron angular correlations from the spontaneous fission of 252Cf and 240Pu oxide samples using a liquid scintillator array capable of pulse-shape discrimination. To compare these correlations to simulations combining the Monte Carlo radiation transport code MCNPX with the fission event generator FREYA. Method: Two different analysis methods were used to study the neutron-neutron correlations with varying energy thresholds. The first is based on setting a light output threshold while the second imposes a time-of-flight cutoff. The second method has the advantage of being truly detector independent. Results: The neutron-neutron correlation modeled by FREYA depends strongly on the sharing of the excitation energy between the two fragments. The measured asymmetry enabled us to adjust the FREYA parameter x in 240Pu , which controls the energy partition between the fragments and is so far inaccessible in other measurements. The 240Pu data in this analysis was the first available to quantify the energy partition for this isotope. The agreement between data and simulation is overall very good formore » 252Cf ( sf ) and 240Pu ( sf ). Conclusions: The asymmetry in the measured neutron-neutron angular distributions can be predicted by FREYA. The shape of the correlation function depends on how the excitation energy is partitioned between the two fission fragments. Lastly, experimental data suggest that the lighter fragment is disproportionately excited.« less

Authors:
 [1];  [1];  [2]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Nuclear and Chemical Sciences Division
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Nuclear and Chemical Sciences Division; Univ. of California, Davis, CA (United States). Dept. of Physics
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation
OSTI Identifier:
1488798
Alternate Identifier(s):
OSTI ID: 1430782
Report Number(s):
LLNL-JRNL-731534
Journal ID: ISSN 2469-9985; PRVCAN; 878683
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 97; Journal Issue: 4; 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

Verbeke, J. M., Nakae, L. F., and Vogt, R.. Neutron-neutron angular correlations in spontaneous fission of Cf252 and Pu240. United States: N. p., 2018. Web. https://doi.org/10.1103/PhysRevC.97.044601.
Verbeke, J. M., Nakae, L. F., & Vogt, R.. Neutron-neutron angular correlations in spontaneous fission of Cf252 and Pu240. United States. https://doi.org/10.1103/PhysRevC.97.044601
Verbeke, J. M., Nakae, L. F., and Vogt, R.. Sun . "Neutron-neutron angular correlations in spontaneous fission of Cf252 and Pu240". United States. https://doi.org/10.1103/PhysRevC.97.044601. https://www.osti.gov/servlets/purl/1488798.
@article{osti_1488798,
title = {Neutron-neutron angular correlations in spontaneous fission of Cf252 and Pu240},
author = {Verbeke, J. M. and Nakae, L. F. and Vogt, R.},
abstractNote = {Background: Angular anisotropy has been observed between prompt neutrons emitted during the fission process. Such an anisotropy arises because the emitted neutrons are boosted along the direction of the parent fragment. Purpose: To measure the neutron-neutron angular correlations from the spontaneous fission of 252Cf and 240Pu oxide samples using a liquid scintillator array capable of pulse-shape discrimination. To compare these correlations to simulations combining the Monte Carlo radiation transport code MCNPX with the fission event generator FREYA. Method: Two different analysis methods were used to study the neutron-neutron correlations with varying energy thresholds. The first is based on setting a light output threshold while the second imposes a time-of-flight cutoff. The second method has the advantage of being truly detector independent. Results: The neutron-neutron correlation modeled by FREYA depends strongly on the sharing of the excitation energy between the two fragments. The measured asymmetry enabled us to adjust the FREYA parameter x in 240Pu , which controls the energy partition between the fragments and is so far inaccessible in other measurements. The 240Pu data in this analysis was the first available to quantify the energy partition for this isotope. The agreement between data and simulation is overall very good for 252Cf ( sf ) and 240Pu ( sf ). Conclusions: The asymmetry in the measured neutron-neutron angular distributions can be predicted by FREYA. The shape of the correlation function depends on how the excitation energy is partitioned between the two fission fragments. Lastly, experimental data suggest that the lighter fragment is disproportionately excited.},
doi = {10.1103/PhysRevC.97.044601},
journal = {Physical Review C},
number = 4,
volume = 97,
place = {United States},
year = {2018},
month = {4}
}

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Works referenced in this record:

Prompt Neutron Emission Probabilities Following Spontaneous and Thermal Neutron Fission
journal, September 1985

  • Boldeman, J. W.; Hines, M. G.
  • Nuclear Science and Engineering, Vol. 91, Issue 1
  • DOI: 10.13182/NSE85-A17133

Neutron crosstalk between liquid scintillators
journal, September 2015

  • Verbeke, J. M.; Prasad, M. K.; Snyderman, N. J.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 794
  • DOI: 10.1016/j.nima.2015.04.019

Verification and validation of the MCNPX-PoliMi code for simulations of neutron multiplicity counting systems
journal, February 2013

  • Clarke, S. D.; Miller, E. C.; Flaska, M.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 700
  • DOI: 10.1016/j.nima.2012.10.025

Initial MCNP6 Release Overview
journal, December 2012

  • Goorley, T.; James, M.; Booth, T.
  • Nuclear Technology, Vol. 180, Issue 3
  • DOI: 10.13182/NT11-135

Angular correlation of neutrons from thermal-neutron fission of 235U
journal, October 1978


Fission Reaction Event Yield Algorithm FREYA 2.0.2
journal, January 2018


Simultaneous investigation of fission fragments and neutrons in 252Cf (SF)
journal, December 1988


Improved predections of neutron detection efficiency for hydrocarbon scintillators from 1 MeV to about 300 MeV
journal, May 1979


Event-by-event study of photon observables in spontaneous and thermal fission
journal, April 2013


Total characterization of neutron detectors with a 252Cf source and a new light output determination
journal, February 2009

  • Kornilov, N. V.; Fabry, I.; Oberstedt, S.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 599, Issue 2-3
  • DOI: 10.1016/j.nima.2008.10.032

Event-by-event study of neutron observables in spontaneous and thermal fission
journal, October 2011


Refined treatment of angular momentum in the event-by-event fission model freya
journal, April 2014


Determination of light output function and angle dependent correction for a stilbene crystal scintillation neutron spectrometer
journal, January 2002

  • Hansen, W.; Richter, D.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 476, Issue 1-2
  • DOI: 10.1016/S0168-9002(01)01430-9

Calculation of fission observables through event-by-event simulation
journal, August 2009


TRIPOLI-4®, CEA, EDF and AREVA reference Monte Carlo code
journal, August 2015


Monte Carlo approach to sequential neutron emission from fission fragments
journal, August 2005


Neutron-neutron angular correlations in spontaneous fission of 252Cf
journal, June 2008

  • Gagarski, A. M.; Guseva, I. S.; Sokolov, V. E.
  • Bulletin of the Russian Academy of Sciences: Physics, Vol. 72, Issue 6
  • DOI: 10.3103/S1062873808060130

Method for measuring multiple scattering corrections between liquid scintillators
journal, July 2016

  • Verbeke, J. M.; Glenn, A. M.; Keefer, G. J.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 825
  • DOI: 10.1016/j.nima.2016.04.003

Event-by-event evaluation of the prompt fission neutron spectrum from 239 Pu ( n , f )
journal, February 2012


MCNP-PoliMi: a Monte-Carlo code for correlation measurements
journal, November 2003

  • Pozzi, Sara A.; Padovani, Enrico; Marseguerra, Marzio
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 513, Issue 3
  • DOI: 10.1016/j.nima.2003.06.012

Monte Carlo approach to sequential γ-ray emission from fission fragments
journal, January 2006


Neutron angular correlations in spontaneous and neutron-induced fission
journal, December 2014


Fission Reaction Event Yield Algorithm, FREYA — For event-by-event simulation of fission
journal, June 2015


Facility for neutron multiplicity measurements in fission
journal, January 2004

  • Dushin, V. N.; Hambsch, F. -J.; Jakovlev, V. A.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 516, Issue 2-3
  • DOI: 10.1016/j.nima.2003.09.029

Velocity and Angular Distributions of Prompt Neutrons from Spontaneous Fission of Cf 252
journal, June 1962

  • Bowman, Harry R.; Thompson, Stanley G.; Milton, J. C. D.
  • Physical Review, Vol. 126, Issue 6
  • DOI: 10.1103/PhysRev.126.2120

Event-by-event study of prompt neutrons from Pu 239 ( n , f )
journal, October 2009


Neutron light output response and resolution functions in EJ-309 liquid scintillation detectors
journal, July 2013

  • Enqvist, Andreas; Lawrence, Christopher C.; Wieger, Brian M.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 715
  • DOI: 10.1016/j.nima.2013.03.032

Angular Correlation of Neutrons from Spontaneous Fission of Cf 252
journal, December 1975


Neutron angular distribution in plutonium-240 spontaneous fission
journal, September 2016

  • Marcath, Matthew J.; Shin, Tony H.; Clarke, Shaun D.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 830
  • DOI: 10.1016/j.nima.2016.05.064

Correlated Neutron Emissions from 252 Cf
journal, October 2014

  • Pozzi, Sara A.; Wieger, Brian; Enqvist, Andreas
  • Nuclear Science and Engineering, Vol. 178, Issue 2
  • DOI: 10.13182/NSE13-96

New prompt spectral γ -ray data from the reaction 252 Cf(sf) and its implication on present evaluated nuclear data files
journal, February 2013


    Works referencing / citing this record:

    Review on the progress in nuclear fission—experimental methods and theoretical descriptions
    journal, September 2018


    High resolution measurement of tagged two-neutron energy and angle correlations in Cf 252 (sf)
    journal, July 2019