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Direct Fast-Neutron Detection: A Progress Report

Description: It is widely acknowledged that Mure neutron-detection technologies will need to offer increased performance at lower cost. One clear route toward these goals is rapid and direct detection of fast neutrons prior to moderation. This report describes progress to date in an effort to achieve such neutron detection via proton recoil within plastic scintillator. Since recording proton-recoil events is of little practical use without a means to discriminate effectively against gamma-ray interactions, … more
Date: October 18, 1998
Creator: Peurrung, AJ; Stromswold, DC; Reeder, PL & Hansen, RR
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Linking continuum mechanics and 3D discrete dislocation simulations

Description: A technique is developed for linking the methods of discrete dislocation dynamics simulation and finite element to treat elasto-plasticity problems. The overall formulation views the plastically deforming crystal as an elastic crystal with continuously changing dislocation microstructure which is tracked by the numerical dynamics simulation. The FEM code needed in this regard is based on linear elasticity only. This formulation presented here is focused on a continuous updating of the outer sha… more
Date: October 18, 1998
Creator: El-Azab, A. A. & Fivel, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Stability of Magnetically Implode Liners for High Energy Density Experiments

Description: Magnetically imploded cylindrical metal shells (z-pinch liners) are attractive drivers for a wide variety of hydrodynamics and material properties experiments. The ultimate utility of liners depends on the acceleration of near-solid density shells to velocities exceeding 20 km/sec with good azimuthal symmetry and axial uniformity. Two pulse power systems (Ranchero and Atlas) currently operational or under development at Los Alamos provide electrical energy adequate to accelerate {approximately}… more
Date: October 18, 1998
Creator: Reinovsky, R. E.; Anderson, W. E.; Atchison, W. L.; Bartsch, R. R.; Clark, D. A.; Ekdahl, C. E. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High Voltage Application of Explosively Formed Fuses

Description: At Los Alamos, the authors have primarily applied Explosively Formed Fuse (EFF) techniques to high current systems. In these systems, the EFF has interrupted currents from 19 to 25 MA, thus diverting the current to low inductance loads. The magnitude of transferred current is determined by the ratio of storage inductance to load inductance, and with dynamic loads, the current has ranged from 12 to 20 MA. In a system with 18 MJ stored energy, the switch operates at a power up to 6 TW. The author… more
Date: October 18, 1998
Creator: Tasker, D. G.; Goforth, J. H.; Fowler, C. M.; Lopez, E. M.; Oona, H.; Marsh, S. P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A Field Theory Approach to Modeling Helical FCG's

Description: Often helical flux-compressor generator (FCG) design codes are essentially circuit codes which utilize known equations for parameterizing circuit elements such as armature and stator inductance. The authors present an analytical model that is based more on first principals. The stator inductance is calculated using a definition of inductance in terms of the magnetic vector-potential. The calculation accounts for winding-pitch, bifurcations, and works for any ratio of length to diameter. The cur… more
Date: October 18, 1998
Creator: Fortgang, C.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Liner Stability Experiments at Pegasus: Diagnostics and Experimental Results

Description: A series of experiments to compare imploding liner performance with magneto-hydrodynamic (MHD) modeling has been performed at the Los Alamos National Laboratory Pegasus II pulse power machine. Liner instability growth originating from initial perturbations machined into the liner has been observed with high resolution. Three major diagnostics were used: radiography, Velocity Interferometer for a Surface of Any Reflector (VISAR), and fiber optic impact pins. For radiography, three flash x-ray un… more
Date: October 18, 1998
Creator: Clark, D.A.; Morgan, D.V. & Rodriguez, G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Atlas Pulsed Power System: a Driver for Multi-Megagauss Fields

Description: Atlas is a pulsed power machine designed for hydrodynamic experiments for the Los Alamos High Energy Density Physics Experimental program. It is presently under construction and should be operational in late 2000. Atlas will store 23 MJ at an erected voltage of 240 kV. This will produce a current of 30 MA into a static load and as much as 32 MA into a dynamic load. The current pulse will have a rise time of {approximately}5{micro}s and will produce a magnetic field driving the impactor liner of… more
Date: October 18, 1998
Creator: Cochrane, J. C.; Bartsch, R. R.; Bennett, G. A.; Bowman, D. W.; Davis, H. A.; Ekdahl, C. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Composite Liner, Multi-Megabar Shock Driver Development

Description: The multi-megabar shock driver development is a series of experiments in support of the Los Alamos High Energy Density Physics Experimental Program. Its purpose is to develop techniques to impact a uniform, stable, composite liner upon a high Z target to produce a multi-megabar shock for EOS studies. To date, experiments have been done on the Pegasus II capacitor bank with a current of {approximately}12MA driving the impactor liner. The driving field is {approximately}200 T at the target radius… more
Date: October 18, 1998
Creator: Cochrane, J. C. Jr.; Bartsch, R. R.; Clark, D. A.; Morgan, D. V.; Anderson, W. E.; Lee, H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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One-and-Two-Dimensional Simulations of Liner Performance at Atlas Parameters

Description: The authors report results of one-and-two-dimensional MHD simulations of an imploding heavy liner in Z-pinch geometry. The driving current has a pulse shape and peak current characteristic of the Atlas pulsed-power facility being constructed at Los Alamos National Laboratory. One-dimensional simulations of heavy composite liners driven by 30 MA currents can achieve velocities on the order of 14 km/sec. Used to impact a tungsten target, the liner produces shock pressures of approximately fourtee… more
Date: October 18, 1998
Creator: Keinigs, R. K.; Atchison, W. L.; Faehl, R. J.; Mclenithan, K. D. & Trainor, R. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Isentropic Compression of Argon and Krypton Using an MC1 Flux Compression Generator

Description: LANL and VNIIEF are performing a set of joint experiments to explore the conductivity and possible metalization of argon and krypton compressed to up to five times normal solid density. The experiments use a magnetic field of several megagauss, generated by a Russian MC1 generator, to compress a metallic tube containing solidified argon or krypton. A probe in the center of the tube measures the electrical conductivity to the walls, and a 70-MeV betatron serves as an x-ray source for three radio… more
Date: October 18, 1998
Creator: Veeser, L.; Ekdahl, C.; Oona, H.; Rodriguez, P.; Schmitt, G.; Solem, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Hydrodynamic Liner Experiments Using the Ranchero Flux Compression Generator System

Description: The authors have developed a system for driving hydrodynamic liners at currents approaching 30 MA. Their 43 cm module will deliver currents of interest, and when fully developed, the 1.4 m module will allow similar currents with more total system inductance. With these systems they can perform interesting physics experiments and support the Atlas development effort.
Date: October 18, 1998
Creator: Goforth, J. H.; Atchison, W. L.; Fowler, C. M.; Lopez, E. A.; Oona, H.; Tasker, D. G. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Optimizing the Ranchero Coaxial Flux Compression Generator

Description: Ranchero is an explosively driven magnetic flux-compression generator that has been developed, over the last four years, as a versatile power source for high energy density physics experiments. It is coaxial, and comprises a 15 cm-diameter armature and a 30-cm stator, each aluminum. The length may be varied to suit the demands of each experiment; thus far, lengths of 0.43 m and 1.4 m have been used. The stator is filled and driven by a high performance cast explosive, and the ultimate performan… more
Date: October 18, 1998
Creator: Tasker, D. G.; Goforth, J. H.; Fowler, C. M.; Lopez, E. A.; Oona, H.; King, J. C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Megagauss Fields During Milliseconds

Description: A non-destructive, one megagauss magnet is now being designed in cooperation between Los Alamos and the National High Magnetic Field Laboratory (NHMFL) through joint funding by the US Department of Energy and the US NSF. The design combines two types of pulsed magnet now in use at the NHMFL: a capacitor-driven 'insert' magnet with a total pulse width of order 10 ms and a much larger 'outsert' magnet with a total pulse width of order 2 seconds that is driven by a controlled power source. The ins… more
Date: October 18, 1998
Creator: Campbell, L.J.; Embury, D.; Han, K.; Parkin, D.M.; Baca, A.; Kihara, K.H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A Review of U.S. High Explosive Pulsed Power Systems

Description: High explosive pulsed power (HEPP) is a specialized subset among pulsed power endeavors which takes advantage of the very high energy density available in both magnetic fields and high explosives (HE). To introduce basic concepts, the author divides HEPP components into generators (magnetic field (B) or current (I)) and switches. Magnetic field and current generators start with magnetic field trapped in a conducting volume. Magnetic flux can be expressed as either LI or BA, where L and A (induc… more
Date: October 18, 1998
Creator: Goforth, J.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Imploding Liner Material Strength Measurements at High-Strain and High Strain Rate

Description: Imploding, cylindrical liners provide a unique, shockless means of simultaneously accessing high strain and high-strain-rate for measurement of strength of materials in plastic flow. The radial convergence in the liner geometry results in the liner thickening as the circumference becomes smaller. Strains of up to {approximately}1.25 and strain rates of up to {approximately}10{sup 6} sec{sup -1} can be readily achieved in a material sample placed inside of an aluminum driver liner, using the Peg… more
Date: October 18, 1998
Creator: Bartsch, R. R.; Lee, H.; Holtkamp, D.; Wright, B.; Stokes, J.; Morgan, D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Modeling of Present and Proposed Magnetized Target Fusion Experiments

Description: In the concept known as Magnetized Target Fusion (MTF) in the United States and Magnitnoye Obzhatiye (MAGO) in Russia, a preheated and magnetized target plasma is hydrodynamically compressed to fusion conditions. Because the magnetic field suppresses losses by electron thermal conduction in the fuel during the target implosion heating process, the compression may be over a much longer time scale than in traditional inertial confinement fusion. Hence ''liner-on-plasma'' compressions, magneticall… more
Date: October 18, 1998
Creator: Sheehey, P.T.; Faehl, R.J.; Kirkpatrick, R.C. & Lindemuth, I.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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