skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Proton core imaging of the nuclear burn in inertial confinement fusion implosions

Abstract

A proton emission imaging system has been developed and used extensively to measure the nuclear burn regions in the cores of inertial confinement fusion implosions. Three imaging cameras, mounted to the 60-beam OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)], use the penetrating 14.7 MeV protons produced from D {sup 3}He fusion reactions to produce emission images of the nuclear burn spatial distribution. The technique relies on penumbral imaging, with different reconstruction algorithms for extracting the burn distributions of symmetric and asymmetric implosions. The hardware and design considerations required for the imaging cameras are described. Experimental data, analysis, and error analysis are presented for a representative symmetric implosion of a fuel capsule with a 17-{mu}m-thick plastic shell and 18 atm D {sup 3}He gas fill. The radial burn profile was found to have characteristic radius R{sub burn}, which we define as the radius containing half the D {sup 3}He reactions, of 32{+-}2 {mu}m (burn radii measured for other capsule types range from 20 to 80 {mu}m). Potential sources of error due to proton trajectory changes from interactions with electric fields and scattering in capsule and camera hardware are estimated with simple analytic and Monte Carlomore » calculations; they are predicted to be small compared with statistical errors. Experimental tests were performed to look for any inconsistencies between results from different cameras and different imaging geometries, or evidence of error due to ambient electric or magnetic fields, and none were found.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1] more »;  [2];  [3] « less
  1. Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
  2. (United States)
  3. (United States) (and others)
Publication Date:
OSTI Identifier:
20779195
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 77; Journal Issue: 4; Other Information: DOI: 10.1063/1.2173788; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALGORITHMS; CAMERAS; CAPSULES; ELECTRIC FIELDS; ERRORS; HELIUM 3; IMPLOSIONS; INERTIAL CONFINEMENT; MAGNETIC FIELDS; MONTE CARLO METHOD; PLASMA; PLASMA DIAGNOSTICS; PLASMA SIMULATION; PROTONS; SPATIAL DISTRIBUTION; THERMONUCLEAR IGNITION; THERMONUCLEAR REACTORS

Citation Formats

DeCiantis, J.L., Seguin, F.H., Frenje, J.A., Berube, V., Canavan, M.J., Chen, C.D., Kurebayashi, S., Li, C.K., Rygg, J.R., Schwartz, B.E., Petrasso, R.D., Delettrez, J.A., Regan, S.P., Smalyuk, V.A., Knauer, J.P., Marshall, F.J., Meyerhofer, D.D., Roberts, S., Sangster, T.C., Stoeckl, C., Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, and Lawrence Livermore National Laboratory, Livermore, California 94550. Proton core imaging of the nuclear burn in inertial confinement fusion implosions. United States: N. p., 2006. Web. doi:10.1063/1.2173788.
DeCiantis, J.L., Seguin, F.H., Frenje, J.A., Berube, V., Canavan, M.J., Chen, C.D., Kurebayashi, S., Li, C.K., Rygg, J.R., Schwartz, B.E., Petrasso, R.D., Delettrez, J.A., Regan, S.P., Smalyuk, V.A., Knauer, J.P., Marshall, F.J., Meyerhofer, D.D., Roberts, S., Sangster, T.C., Stoeckl, C., Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, & Lawrence Livermore National Laboratory, Livermore, California 94550. Proton core imaging of the nuclear burn in inertial confinement fusion implosions. United States. doi:10.1063/1.2173788.
DeCiantis, J.L., Seguin, F.H., Frenje, J.A., Berube, V., Canavan, M.J., Chen, C.D., Kurebayashi, S., Li, C.K., Rygg, J.R., Schwartz, B.E., Petrasso, R.D., Delettrez, J.A., Regan, S.P., Smalyuk, V.A., Knauer, J.P., Marshall, F.J., Meyerhofer, D.D., Roberts, S., Sangster, T.C., Stoeckl, C., Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, and Lawrence Livermore National Laboratory, Livermore, California 94550. Sat . "Proton core imaging of the nuclear burn in inertial confinement fusion implosions". United States. doi:10.1063/1.2173788.
@article{osti_20779195,
title = {Proton core imaging of the nuclear burn in inertial confinement fusion implosions},
author = {DeCiantis, J.L. and Seguin, F.H. and Frenje, J.A. and Berube, V. and Canavan, M.J. and Chen, C.D. and Kurebayashi, S. and Li, C.K. and Rygg, J.R. and Schwartz, B.E. and Petrasso, R.D. and Delettrez, J.A. and Regan, S.P. and Smalyuk, V.A. and Knauer, J.P. and Marshall, F.J. and Meyerhofer, D.D. and Roberts, S. and Sangster, T.C. and Stoeckl, C. and Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 and Lawrence Livermore National Laboratory, Livermore, California 94550},
abstractNote = {A proton emission imaging system has been developed and used extensively to measure the nuclear burn regions in the cores of inertial confinement fusion implosions. Three imaging cameras, mounted to the 60-beam OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)], use the penetrating 14.7 MeV protons produced from D {sup 3}He fusion reactions to produce emission images of the nuclear burn spatial distribution. The technique relies on penumbral imaging, with different reconstruction algorithms for extracting the burn distributions of symmetric and asymmetric implosions. The hardware and design considerations required for the imaging cameras are described. Experimental data, analysis, and error analysis are presented for a representative symmetric implosion of a fuel capsule with a 17-{mu}m-thick plastic shell and 18 atm D {sup 3}He gas fill. The radial burn profile was found to have characteristic radius R{sub burn}, which we define as the radius containing half the D {sup 3}He reactions, of 32{+-}2 {mu}m (burn radii measured for other capsule types range from 20 to 80 {mu}m). Potential sources of error due to proton trajectory changes from interactions with electric fields and scattering in capsule and camera hardware are estimated with simple analytic and Monte Carlo calculations; they are predicted to be small compared with statistical errors. Experimental tests were performed to look for any inconsistencies between results from different cameras and different imaging geometries, or evidence of error due to ambient electric or magnetic fields, and none were found.},
doi = {10.1063/1.2173788},
journal = {Review of Scientific Instruments},
number = 4,
volume = 77,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}
  • The significance and nature of ion kinetic effects in D{sup 3}He-filled, shock-driven inertial confinement fusion implosions are assessed through measurements of fusion burn profiles. Over this series of experiments, the ratio of ion-ion mean free path to minimum shell radius (the Knudsen number, N{sub K}) was varied from 0.3 to 9 in order to probe hydrodynamic-like to strongly kinetic plasma conditions; as the Knudsen number increased, hydrodynamic models increasingly failed to match measured yields, while an empirically-tuned, first-step model of ion kinetic effects better captured the observed yield trends [Rosenberg et al., Phys. Rev. Lett. 112, 185001 (2014)]. Here, spatiallymore » resolved measurements of the fusion burn are used to examine kinetic ion transport effects in greater detail, adding an additional dimension of understanding that goes beyond zero-dimensional integrated quantities to one-dimensional profiles. In agreement with the previous findings, a comparison of measured and simulated burn profiles shows that models including ion transport effects are able to better match the experimental results. In implosions characterized by large Knudsen numbers (N{sub K} ∼ 3), the fusion burn profiles predicted by hydrodynamics simulations that exclude ion mean free path effects are peaked far from the origin, in stark disagreement with the experimentally observed profiles, which are centrally peaked. In contrast, a hydrodynamics simulation that includes a model of ion diffusion is able to qualitatively match the measured profile shapes. Therefore, ion diffusion or diffusion-like processes are identified as a plausible explanation of the observed trends, though further refinement of the models is needed for a more complete and quantitative understanding of ion kinetic effects.« less
  • The significance and nature of ion kinetic effects in D³He-filled, shock-driven inertial confinement fusion implosions are assessed through measurements of fusion burn profiles. Over this series of experiments, the ratio of ion-ion mean free path to minimum shell radius (the Knudsen number, N K) was varied from 0.3 to 9 in order to probe hydrodynamic-like to strongly kinetic plasma conditions; as the Knudsen number increased, hydrodynamic models increasingly failed to match measured yields, while an empirically-tuned, first-step model of ion kinetic effects better captured the observed yield trends [Rosenberg et al., Phys. Rev. Lett. 112, 185001 (2014)]. Here, spatially resolvedmore » measurements of the fusion burn are used to examine kinetic ion transport effects in greater detail, adding an additional dimension of understanding that goes beyond zero-dimensional integrated quantities to one-dimensional profiles. In agreement with the previous findings, a comparison of measured and simulated burn profiles shows that models including ion transport effects are able to better match the experimental results. In implosions characterized by large Knudsen numbers (N K ~ 3), the fusion burn profiles predicted by hydrodynamics simulations that exclude ion mean free path effects are peaked far from the origin, in stark disagreement with the experimentally observed profiles, which are centrally peaked. In contrast, a hydrodynamics simulation that includes a model of ion diffusion is able to qualitatively match the measured profile shapes. Therefore, ion diffusion or diffusion-like processes are identified as a plausible explanation of the observed trends, though further refinement of the models is needed for a more complete and quantitative understanding of ion kinetic effects.« less
  • Cited by 6
  • A compact, step range filter proton spectrometer has been developed for the measurement of the absolute DD proton spectrum, from which yield and areal density (ρR) are inferred for deuterium-filled thin-shell inertial confinement fusion implosions. This spectrometer, which is based on tantalum step-range filters, is sensitive to protons in the energy range 1-9 MeV and can be used to measure proton spectra at mean energies of ~1-3 MeV. It has been developed and implemented using a linear accelerator and applied to experiments at the OMEGA laser facility and the National Ignition Facility (NIF). Modeling of the proton slowing in themore » filters is necessary to construct the spectrum, and the yield and energy uncertainties are ±<10% in yield and ±120 keV, respectively. This spectrometer can be used for in situ calibration of DD-neutron yield diagnostics at the NIF.« less