Reaction-in-flight neutrons as a signature for shell mixing in National Ignition Facility capsules

Journal Article · Fri Jan 15 00:00:00 EST 2010 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3274947· OSTI ID:21347097

Hayes, A C; Bradley, P A; Grim, G P; Jungman, Gerard; Wilhelmy, J B ^[1]

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1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

Analytic calculations and results from computational simulations are presented that suggest that reaction-in-flight (RIF) neutrons can be used to diagnose mixing of the ablator shell material into the fuel in deuterium-tritium (DT) capsules designed for the National Ignition Facility (NIF) [J. A. Paisner, J. D. Boyes, S. A. Kumpan, W. H. Lowdermilk, and M. S. Sorem, Laser Focus World 30, 75 (1994)]. Such mixing processes in NIF capsules are of fundamental physical interest and can have important effects on capsule performance, quenching the total thermonuclear yield. The sensitivity of RIF neutrons to hydrodynamical mixing arises through the dependence of RIF production on charged-particle stopping lengths in the mixture of DT fuel and ablator material. Since the stopping power in the plasma is a sensitive function of the electron temperature and density, it is also sensitive to mix. RIF production scales approximately inversely with the degree of mixing taking place, and the ratio of RIF to down-scattered neutrons provides a measure of the mix fraction and/or the mixing length. For sufficiently high-yield capsules, where spatially resolved RIF images may be possible, neutron imaging could be used to map RIF images into detailed mix images.

• OSTI ID: 21347097
• Journal Information: Physics of Plasmas, Vol. 17, Issue 1; Other Information: DOI: 10.1063/1.3274947; (c) 2010 American Institute of Physics; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CAPSULES
DEUTERIUM
ELECTRON TEMPERATURE
MIXING
NEUTRONS
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA SIMULATION
STOPPING POWER
THERMONUCLEAR FUELS
TRITIUM
US NATIONAL IGNITION FACILITY
BARYONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CONTAINERS
ELEMENTARY PARTICLES
FERMIONS
FUELS
HADRONS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
NUCLEONS
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
SIMULATION
STABLE ISOTOPES
YEARS LIVING RADIOISOTOPES