Issue 10 Volume 41 May 16, 2003

sensitive to the x-ray spectrum as well as the composition and energy of the capsule debris we also present these for this target.
A novel implosion scheme for the Fast Igniter fusion scenario that minimizes the amount of coronal plasma that the igniting
laser beam must penetrate is described. We describe recently derived scaling laws that relate the minimum value of the
incoming fuel kinetic energy to the peak drive pressure, the fuel adiabat and the implosion velocity for capsules that use the
kinetic energy of the implosion to heat the hot spot to ignition temperatures.
NTIS
Laboratories; Plasmas (Physics); Inertial Fusion (Reactor); Targets
20030037033 Lawrence Livermore National Lab., Livermore, CA
Spherical Harmonic Solutions to the 3D Kobayashi Benchmark Suite
Brown, P. N.; Chang, B.; Hanebutte, U. R.; Dec. 29, 1999; In English
Report No.(s): DE2002-791668; UCRL-JC-135163; No Copyright; Avail: National Technical Information Service (NTIS)
Spherical harmonic solutions of order 5, 9 and 21 on spatial grids containing up to 3.3 million cells are presented for the
Kobayashi benchmark suite. This suite of three problems with simple geometry of pure absorber with large void region was
proposed by Professor Kobayashi at an OECD/NEA meeting in 1996. Each of the three problems contains a source, a void
and a shield region. Problem 1 can best be described as a box in a box problem, where a source region is surrounded by a
square void region which itself is embedded in a square shield region. Problems 2 and 3 represent a shield with a void duct.
Problem 2 having a straight and problem 3 a dog leg shaped duct. A pure absorber and a 50\% scattering case are considered
for each of the three problems. The solutions have been obtained with Ardra, a scalable, parallel neutron transport code
developed at Lawrence Livermore National Laboratory (LLNL). The Ardra code takes advantage of a two-level parallelization
strategy, which combines message passing between processing nodes and thread based parallelism amongst processors on each
node. All calculations were performed on the IBM ASCI Blue-Pacific computer at LLNL.
NTIS
Reactor Physics; Spherical Harmonics; Standards
20030037091 Lawrence Livermore National Lab., Livermore, CA
LLNL Accelerator Mass Spectrometry System for Biochemical (14)C-Measurements
Ognibene, T. J.; Bench, G.; Brown, T. A.; Vogel, J. S.; Oct. 31, 2002; 20 pp.
Report No.(s): DE2002-15001999; No Copyright; Avail: Department of Energy Information Bridge
We report on recent improvements made to our 1 MV accelerator mass spectrometry system that is dedicated to (14)C
quantification of biochemical samples. Increased vacuum pumping capacity near the high voltage terminal has resulted in a
2-fold reduction of system backgrounds to 0.04 amol (14)C/mg carbon. Carbon ion transmission through the accelerator has
also improved a few percent. We have also developed tritium measurement capability on this spectrometer.
NTIS
Particle Accelerators; Biochemistry; Mass Spectroscopy
20030037105 Lawrence Livermore National Lab., Livermore, CA
High Intensity Laser Interactions with Atomic Clusters
Ditmire, T.; Aug. 07, 2000; 10 pp.
Report No.(s): DE2002-15001992; No Copyright; Avail: Department of Energy Information Bridge
The development of ultrashort pulse table top lasers with peak pulse powers in excess of 1 TW has permitted an access
to studies of matter subject to unprecedented light intensities. Such interactions have accessed exotic regimes of multiphoton
atomic and high energy-density plasma physics. Very recently, the nature of the interactions between these very high intensity
laser pulses and atomic clusters of a few hundred to a few thousand atoms has come under study. Such studies have found
some rather unexpected results, including the striking finding that these interactions appear to be more energetic than
interactions with either single atoms or solid density plasmas. Recent experiments have shown that the explosion of such
clusters upon intense irradiation can expel ions from the cluster with energies from a few keV to nearly 1 MeV. This
phenomenon has recently been exploited to produce DD fusion neutrons in a gas of exploding deuterium clusters. Under this
project, we have undertaken a general study of the intense femtosecond laser cluster interaction. Our goal is to understand the
macroscopic and microscopic coupling between the laser and the clusters with the aim of optimizing high flux fusion neutron
production from the exploding deuterium clusters or the x-ray yield in the hot plasmas that are produced in this interaction.
In particular, we are studying the physics governing the cluster explosions. The interplay between a traditional Coulomb
explosion description of the cluster disassembly and a plasma-like hydrodynamic explosion is not entirely understood,
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