Velocity correction for neutron activation diagnostics at the NIF

Rinderknecht, Hans G.; Bionta, R.; Grim, G.; Hatarik, R.; Khater, H.; Schlossberg, D.; Yeamans, C.

doi:10.1063/1.5038734

Title: Velocity correction for neutron activation diagnostics at the NIF

Abstract

The velocity distribution of the hotspot in an inertial confinement fusion implosion changes the energy spectra of fusion neutrons emitted from the experiment as a function of viewing angle. These velocity-induced spectral changes affect the response of neutron activation diagnostics (NADs) positioned around the experiment and must be accounted for to correctly extract information about areal density (ρR) asymmetry from the data. Three mechanisms through which average hotspot velocity affects NAD activation are addressed: change in activation cross section due to the Doppler shift of the mean neutron energy, kinematic focusing of neutron fluence, and change in the scattering cross section due to the Doppler shift. Using the hotspot velocity inferred from neutron time-of-flight measurements of D-T and D-D fusion neutrons, the hotspot velocity is shown to account for the observed NAD activation asymmetry in a calibration shot with negligible fuel ρR. Finally, a robust method to evaluate uncertainties in spherical-harmonic fits to the NAD data due to the velocity correction and detector uncertainty is discussed.

Authors:

^[1]; Bionta, R. ^[1]; Grim, G. ^[1]; Hatarik, R. ^[1]; Khater, H. ^[1];

^[1];

^[1]

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:: Mon Oct 01 00:00:00 EDT 2018

Research Org.:: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:: USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:: 1479059

Alternate Identifier(s):: OSTI ID: 1476964

Report Number(s):: LLNL-JRNL-750006
Journal ID: ISSN 0034-6748; 935047

Grant/Contract Number:: AC52-07NA27344

Resource Type:: Accepted Manuscript

Journal Name:: Review of Scientific Instruments

Additional Journal Information:: Journal Volume: 89; Journal Issue: 10; Journal ID: ISSN 0034-6748

Publisher:: American Institute of Physics (AIP)

Country of Publication:: United States

Language:: English

Subject:: 47 OTHER INSTRUMENTATION; Lasers

Citation Formats


                    Rinderknecht, Hans G., Bionta, R., Grim, G., Hatarik, R., Khater, H., Schlossberg, D., and Yeamans, C. Velocity correction for neutron activation diagnostics at the NIF.  United States: N. p., 2018. 
Web.  doi:10.1063/1.5038734.

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                    Rinderknecht, Hans G., Bionta, R., Grim, G., Hatarik, R., Khater, H., Schlossberg, D., & Yeamans, C. Velocity correction for neutron activation diagnostics at the NIF.  United States.  https://doi.org/10.1063/1.5038734

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                    Rinderknecht, Hans G., Bionta, R., Grim, G., Hatarik, R., Khater, H., Schlossberg, D., and Yeamans, C. Mon .  
"Velocity correction for neutron activation diagnostics at the NIF".  United States.  https://doi.org/10.1063/1.5038734.  https://www.osti.gov/servlets/purl/1479059.

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@article{osti_1479059,

  title        = {Velocity correction for neutron activation diagnostics at the NIF},

  author       = {Rinderknecht, Hans G. and Bionta, R. and Grim, G. and Hatarik, R. and Khater, H. and Schlossberg, D. and Yeamans, C.},

  abstractNote = {The velocity distribution of the hotspot in an inertial confinement fusion implosion changes the energy spectra of fusion neutrons emitted from the experiment as a function of viewing angle. These velocity-induced spectral changes affect the response of neutron activation diagnostics (NADs) positioned around the experiment and must be accounted for to correctly extract information about areal density (ρR) asymmetry from the data. Three mechanisms through which average hotspot velocity affects NAD activation are addressed: change in activation cross section due to the Doppler shift of the mean neutron energy, kinematic focusing of neutron fluence, and change in the scattering cross section due to the Doppler shift. Using the hotspot velocity inferred from neutron time-of-flight measurements of D-T and D-D fusion neutrons, the hotspot velocity is shown to account for the observed NAD activation asymmetry in a calibration shot with negligible fuel ρR. Finally, a robust method to evaluate uncertainties in spherical-harmonic fits to the NAD data due to the velocity correction and detector uncertainty is discussed.},

  doi          = {10.1063/1.5038734},

  journal      = {Review of Scientific Instruments},

  number       = 10,

  volume       = 89,

  place        = {United States},

  year         = {Mon Oct 01 00:00:00 EDT 2018},

  month        = {Mon Oct 01 00:00:00 EDT 2018}

}

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Works referenced in this record:

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Ballabio, L.; Källne, J.; Gorini, G.
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Hatarik, R.; Nora, R. C.; Spears, B. K.
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Dynamic high energy density plasma environments at the National Ignition Facility for nuclear science research
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Cerjan, Ch J.; Bernstein, L.; Hopkins, L. Berzak
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journal, October 2012

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Works referencing / citing this record:

Synthetic nuclear diagnostics for inferring plasma properties of inertial confinement fusion implosions
journal, December 2018

Crilly, A. J.; Appelbe, B. D.; McGlinchey, K.
Physics of Plasmas, Vol. 25, Issue 12
DOI: 10.1063/1.5027462

A 3D dynamic model to assess the impacts of low-mode asymmetry, aneurysms and mix-induced radiative loss on capsule performance across inertial confinement fusion platforms
journal, December 2018

Springer, P. T.; Hurricane, O. A.; Hammer, J. H.
Nuclear Fusion, Vol. 59, Issue 3
DOI: 10.1088/1741-4326/aaed65

Progress of indirect drive inertial confinement fusion in the United States
journal, July 2019

Kline, J. L.; Batha, S. H.; Benedetti, L. R.
Nuclear Fusion, Vol. 59, Issue 11
DOI: 10.1088/1741-4326/ab1ecf

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Similar Records

Title: Velocity correction for neutron activation diagnostics at the NIF

Abstract

Citation Formats

Relativistic calculation of fusion product spectra for thermonuclear plasmas journal, November 1998

The Spatially Distributed Neutron Activation Diagnostic FNADs at the National Ignition Facility journal, May 2017

The National Ignition Facility neutron time-of-flight system and its initial performance (invited) journal, October 2010

Using multiple neutron time of flight detectors to determine the hot spot velocity journal, October 2018

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Testing a new NIF neutron time-of-flight detector with a bibenzyl scintillator on OMEGA journal, October 2012

Interpreting inertial fusion neutron spectra journal, February 2016

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ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology journal, December 2006

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The National Ignition Facility neutron time-of-flight system and its initial performance (invited)
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Using multiple neutron time of flight detectors to determine the hot spot velocity
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Dynamic high energy density plasma environments at the National Ignition Facility for nuclear science research
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Testing a new NIF neutron time-of-flight detector with a bibenzyl scintillator on OMEGA
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Interpreting inertial fusion neutron spectra
journal, February 2016

Capsule modeling of high foot implosion experiments on the National Ignition Facility
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Mode 1 drive asymmetry in inertial confinement fusion implosions on the National Ignition Facility
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