Measurement of areal density in the ablators of inertial-confinement-fusion capsules via detection of ablator (n, n Prime {gamma}) gamma-ray emission

Journal Article · Mon Apr 15 00:00:00 EDT 2013 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4799799· OSTI ID:22130456

Hoffman, N. M.; Herrmann, H. W.; Kim, Y. H.; Hsu, H. H.; Young, C. S.; Mack, J. M.; Wilson, D. C.; Langenbrunner, J. R.; Evans, S. C.; Sedillo, T. J. ^[1]; Horsfield, C. J.; Rubery, M. S. ^[2]; Miller, E. K. ^[3]; Grafil, E. ^[4]; Stoeffl, W.; Church, J. A. ^[5]; Glebov, V. Yu.; Duffy, T. ^[6]

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1. Los Alamos National Laboratory, P. O. Box 1663, Los Alamos, New Mexico 87545 (United States)
2. Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom)
3. National Security Technologies, LLC, Santa Barbara, California 93111 (United States)
4. Colorado School of Mines, Golden, Colorado 80401 (United States)
5. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
6. Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

We report the first gamma-ray-based measurements of the areal density of ablators in inertial-confinement-fusion capsule implosions. The measurements, made at the OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)], used observations of gamma rays arising from inelastic scattering of 14.1-MeV deuterium-tritium (DT) neutrons on {sup 12}C nuclei in the compressed plastic ablators. The emission of {sup 12}C(n,n Prime {gamma}) gamma rays from the capsules is detected using the Gamma Reaction History instrument [H. W. Herrmann et al., J. Phys.: Conf. Ser. 244, 032047 (2010)] operating at OMEGA. From the ratio of a capsule's {sup 12}C(n,n Prime {gamma}) emission to the emission from the same processes in an in situ reference graphite 'puck' of known mass and geometry [N. M. Hoffman et al., in IFSA 2011 proceedings (submitted)], we determine the time-averaged areal density of {sup 12}C in the capsule's compressed ablator. Measured values of total ablator areal density for thirteen imploded capsules, in the range 23 {+-} 10 to 58 {+-} 14 mg/cm{sup 2}, are comparable to values calculated in 1D radiation-hydrodynamic simulations, and measured by charged-particle techniques.

• OSTI ID: 22130456
• Journal Information: Physics of Plasmas, Vol. 20, Issue 4; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
36 MATERIALS SCIENCE
ABLATION
CAPSULES
CARBON 12
CHARGED PARTICLES
COMPARATIVE EVALUATIONS
DEUTERIUM
EXPLOSIONS
GAMMA RADIATION
GRAPHITE
HYDRODYNAMIC MODEL
INELASTIC SCATTERING
INERTIAL CONFINEMENT
LASERS
LIGHT TRANSMISSION
MEV RANGE 10-100
NEUTRONS
PLASMA DENSITY
PLASMA DIAGNOSTICS
SIMULATION
TRITIUM