Program - Brookhaven National Laboratory

a modified Lorentzian model (MLO) of the radiative strenght function; and integrated prompt fission
neutron spectra modeling that may include emissive contributions from (n,xnf) reactions, and neutron
emission from fission fragments calculated by Los Alamos or Kornilov models. Impact of the advanced
modeling on inelastic scattering cross section and corresponding uncertainties is being assessed both by
comparison with selected microscopic experimental data and integral criticality benchmarks including
measured reaction rates (e.g. FLAPTOP and BIG TEN). Benchmark calculations provide feedback to
improve the reaction modeling and reduce both model and model-parameters uncertainties. Improvement
of existing libraries will be discussed.
IA 2 9:15 AM
Plasma Nuclear Science: Nuclear Science in Hot, Dense, and Dynamic Laboratory Plasmas
D.P. McNabb, P.A. Amendt, R.N. Boyd, S.P. Hatchett, J.E. Pino, S. Quaglioni, J.R. Rygg, I.J.
Thompson, Lawrence Livermore National Laboratory. D.T. Casey, J.A. Frenje, M. Gatu Johnson, M.J.-E.
Manuel, N. Sinenian, A.B. Zylstra, F.H. Séguin, C.K. Li, R.D. Petrasso, Plasma Science Fusion Center,
MIT. C. Forrest, V. Yu Glebov, P.B. Radha, D.D. Meyerhofer, T.C. Sangster, Laboratory for Laser
Energetics, University of Rochester. A. D. Bacher, Department of Physics, Indiana University. H. W.
Herrmann, Y. H. Kim, Los Alamos National Laboratory.
The plasma environments created using laser-driven inertial confinement fusion implosion at the National
Ignition Facility [1] and OMEGA Laser Facility [2] probe new degrees of freedom in nuclear reactions and
nuclear-atomic interactions. These thermal plasma environments closely resemble the burning core of a
star where the reactants are ionized and the electrons are in continuum states. The fusion reactions in
these plasmas can also lead to an extremely high neutron brightness, 10 orders of magnitude higher than
produced in conventional accelerator and reactor facilities. However, these facilities also present challenges
for nuclear astrophysics measurements because the plasma environment is a complex and dynamic system
that is difficult to model. Results from three studies are presented: (1) the n-T differential elastic
scattering cross section at En = 14 MeV [3], (2) the stellar 3 He( 3 He,2p) 4 He (or 3He3He) reaction, the dominant
energy-producing step in the solar proton-proton chain, and (3) its charge conjugate reaction, the
T(t,2n) 4 He (or tt) reaction [4]. These measurements were carried out at OMEGA, where gas-filled spherical
capsules were spherically irradiated with powerful lasers to compress and heat the fuel to high enough
temperatures and densities for significant nuclear reactions to occur. Reactant products are measured
with particle spectrometers designed to work in this special environment [5]. While the n-T differential
scattering results were consistent with expectations, the results from the tt measurements are puzzling on
two fronts. First, the tt rate is higher than expected based on accelerator measurements [6]. Second, in
contrast to accelerator experiments conducted at CM energies above 100 keV [4], the tt neutron spectrum
shows a smaller n+ 5 He reaction channel at a CM energy of 23 keV [4]. This suggests that the reaction
mechanism is changing at lower energies. These results, implications and possibilities for future nuclear
astrophysics measurements will be discussed. * Prepared by LLNL under Contract DE-AC52-07NA27344
and supported in part by NLUF (DOE), FSC (UR), US DOE, LLE, LLNL, and GA under DOE.
1. G. H. Miller et al., Nucl. Fusion 44, S228 (2004). 2. T.R. Boehly et al., Optics Communications 133,
495 (1997). 3. J.A. Frenje et al., Physical Review Letters 107, 122502 (2011). 4. D.T. Casey et al., Physical
Review Letters 108, 075002 (2012); D.T. Casey et al., Physical Review Letters, 109, 025003 (2012).
5. F.H. Séguin et al., Review of Scientific Instruments 74, 975 (2003). 6. N. Jarmie and R. E. Brown,
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and
Atoms 10-11 (Part 1), 405-410 (1985).
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