High-power pulsed lasers (open access)

High-power pulsed lasers

The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization.
Date: April 2, 1980
Creator: Holzrichter, J.F.
Object Type: Report
System: The UNT Digital Library
RTNS-II targets: cooling channel collapse under simulated bonding conditions (open access)

RTNS-II targets: cooling channel collapse under simulated bonding conditions

We experimentally determined the pressure limits that can be used to autoclave-bond RTNS-II targets without crushing the internal cooling channels. The maximum pressures are 40 to 55 MPa (6 to 8 ksi) in the 300-to-450/sup 0/C temperature regime.
Date: April 2, 1981
Creator: Ludemann, W.D.; Brady, R.L. & Schumacher, B.J.
Object Type: Report
System: The UNT Digital Library
HOTSPUR progress report: neutron source spectrum characterization, and /sup 6/Li(n,x. cap alpha. ) and /sup 7/Li(n,x. cap alpha. ) cross section determination (open access)

HOTSPUR progress report: neutron source spectrum characterization, and /sup 6/Li(n,x. cap alpha. ) and /sup 7/Li(n,x. cap alpha. ) cross section determination

As a prerequisite to high accuracy measurements involving the bulk configuration of /sup 6/LiD we must have a good grasp of the details of the RTNS-I neutron source energy spectrum. Experiments to this end involving neutron yield vs deuteron energy, ratios of foil activation of selected elements, and pulse height distributions of a Si surface barrier detector are described. With this knowledge, the /sup 4/He-production cross sections for /sup 6/Li and /sup 7/Li are found experimentally to be 0.512b and 0.336b, respectively, at anti E/sub N/ = 15.0 MeV in free-field geometry. 14 references.
Date: April 2, 1984
Creator: Goldberg, E. & Haight, R.
Object Type: Report
System: The UNT Digital Library
Carbon stress gage comparison (open access)

Carbon stress gage comparison

None
Date: April 2, 1975
Creator: Shay, W. M.; Kuhlman, J. R.; Carter, G. W. & Lee, D.
Object Type: Report
System: The UNT Digital Library
WACC-WTG Review Comment Sheets (open access)

WACC-WTG Review Comment Sheets

This report is a letter about a review of the Quality Assurance Project Plan for the INEL Waste Isolation Pilot Plant Waste Characterization Project.'' The author of the letter recommended the approval of the quality assurance program. However in his review, several observations were made and were requested to be added to the program. Examples of these observations were safety of personnel involved in the program, safe characterization of hazardous materials studied, quality of calibrations required for measurement objectives, and reporting of hazardous sampling. (MB)
Date: April 2, 1991
Creator: Spencer, W. A.
Object Type: Report
System: The UNT Digital Library
Initial Results of the Tandem Mirror Experiment (TMX) at the Lawrence Livermore Laboratory (open access)

Initial Results of the Tandem Mirror Experiment (TMX) at the Lawrence Livermore Laboratory

Initial experimental results from the Tandem Mirror Experiment (TMX) are presented. Axial profiles of the plasma density and potential necessary for electrostatically enhanced confinement of the central-cell ions have been generated and sustained for the duration of neutral-beam injection. The resulting central-cell ion confinement against axial loss is improved by a factor as large as 9 above that given by magnetic confinement alone. The plasma exhibits gross magnetohydrodynamic stability and microstability. Under some conditions, a residual level of ion cyclotron fluctuations in the end cells heats the central-cell ions and degrades their confinement.
Date: April 2, 1980
Creator: Grubb, D. P.; Anderson, C. A.; Casper, T. A.; Clauser, J. F.; Coensgen, F. H.; Correll, D. L. et al.
Object Type: Article
System: The UNT Digital Library

Fuel Cell Vehicle Learning Demonstration: Spring 2008 Results

Presentation prepared for the 2008 National Hydrogen Association Conference that describes the spring 2008 results for DOE's Fuel Cell Vehicle Learning Demonstration.
Date: April 2, 2008
Creator: Wipke, K.; Sprik, S.; Kurtz, J. & Garbak, J.
Object Type: Presentation
System: The UNT Digital Library
Studies of Exclusive e+ e- to hadrons Reactions with Baryons and Strange Particles using Initial State Radiation at BaBar (open access)

Studies of Exclusive e+ e- to hadrons Reactions with Baryons and Strange Particles using Initial State Radiation at BaBar

None
Date: April 2, 2008
Creator: Serednyakov, S. I.
Object Type: Article
System: The UNT Digital Library
Ambient-temperature Conditioning as a Probe of Double-C Transformation Mechanisms in Pu-2.0 at. % Ga (open access)

Ambient-temperature Conditioning as a Probe of Double-C Transformation Mechanisms in Pu-2.0 at. % Ga

The gallium-stabilized Pu-2.0 at. % Ga alloy undergoes a partial or incomplete low-temperature martensitic transformation from the metastable {delta} phase to the gallium-containing, monoclinic {alpha}{prime} phase near -100 C. This transformation has been shown to occur isothermally and it displays anomalous double-C kinetics in a time-temperature-transformation (TTT) diagram, where two nose temperatures anchoring an upper- and lower-C describe minima in the time for the initiation of transformation. The underlying mechanisms responsible for the double-C behavior are currently unresolved, although recent experiments suggest that a conditioning treatment--wherein, following an anneal at 375 C, the sample is held at a sub-anneal temperature for a period of time--significantly influences the upper-C of the TTT diagram. As such, elucidating the effects of the conditioning treatment upon the {delta} {yields} {alpha}{prime} transformation can provide valuable insights into the fundamental mechanisms governing the double-C kinetics of the transition. Following a high-temperature anneal, a differential scanning calorimeter (DSC) was used to establish an optimal conditioning curve that depicts the amount of {alpha}{prime} formed during the transformation as a function of conditioning temperature for a specified time. With the optimal conditioning curve as a baseline, the DSC was used to explore the circumstances under which the effects of …
Date: April 2, 2008
Creator: Jeffries, J R; Blobaum, K M; Wall, M A & Schwartz, A J
Object Type: Article
System: The UNT Digital Library
Cosmic Ray Results From the CosmoALEPH Experiment (open access)

Cosmic Ray Results From the CosmoALEPH Experiment

None
Date: April 2, 2008
Creator: Grupen, C.; Hashim, N. -O.; Jost, B.; Maciuc, F.; Luitz, S.; Mailov, A. et al.
Object Type: Article
System: The UNT Digital Library
Preparation of Size-tunable, Highly Monodisperse PVP-Protected Pt-nanoparticles by Seed-mediated Growth (open access)

Preparation of Size-tunable, Highly Monodisperse PVP-Protected Pt-nanoparticles by Seed-mediated Growth

We demonstrate a preparative method which produces highly-monodisperse Pt-nanoparticles of tunable size without the external addition of seed particles. Hexachloroplatinic acid is dosed slowly to an ethylene glycol solution at 120 C and reduced in the presence of a stabilizing polymer poly-N-vinylpyrollidone (PVP). Slow addition of the Pt-salt first will first lead to the formation of nuclei (seeds) which then grow further to produce larger particles of any desired size between 3 and 8nm. The amount of added hexachloroplatinic acid precursor controls the size of the final nanoparticle product. TEM was used to determine size and morphology and to confirm the crystalline nature of the nanoparticles. Good reproducibility of the technique was demonstrated. Above 7nm, the particle shape and morphology changes suddenly indicating a change in the deposition selectivity of the Pt-precursor from (100) towards (111) crystal faces and breaking up of larger particles into smaller entities.
Date: April 2, 2008
Creator: Koebel, Matthias Michael; Jones, Louis C. & Somorjai, Gabor A.
Object Type: Article
System: The UNT Digital Library
ARCHITECTURE OF A CHARGE-TRANSFER STATE REGULATING LIGHT HARVESTING IN A PLANT ANTENNA PROTEIN (open access)

ARCHITECTURE OF A CHARGE-TRANSFER STATE REGULATING LIGHT HARVESTING IN A PLANT ANTENNA PROTEIN

Energy-dependent quenching of excess absorbed light energy (qE) is a vital mechanism for regulating photosynthetic light harvesting in higher plants. All of the physiological characteristics of qE have been positively correlated with charge-transfer between coupled chlorophyll and zeaxanthin molecules in the light-harvesting antenna of photosystem II (PSII). In this work, we present evidence for charge-transfer quenching in all three of the individual minor antenna complexes of PSII (CP29, CP26, and CP24), and we conclude that charge-transfer quenching in CP29 involves a de-localized state of an excitonically coupled chlorophyll dimer. We propose that reversible conformational changes in CP29 can `tune? the electronic coupling between the chlorophylls in this dimer, thereby modulating the energy of the chlorophylls-zeaxanthin charge-transfer state and switching on and off the charge-transfer quenching during qE.
Date: April 2, 2008
Creator: Fleming, Graham; Ahn, Tae Kyu; Avenson, Thomas J.; Ballottari, Matteo; Cheng, Yuan-Chung; Niyogi, Krishna K. et al.
Object Type: Article
System: The UNT Digital Library
Chemical Kinetic Modeling of Hydrogen Combustion Limits (open access)

Chemical Kinetic Modeling of Hydrogen Combustion Limits

A detailed chemical kinetic model is used to explore the flammability and detonability of hydrogen mixtures. In the case of flammability, a detailed chemical kinetic mechanism for hydrogen is coupled to the CHEMKIN Premix code to compute premixed, laminar flame speeds. The detailed chemical kinetic model reproduces flame speeds in the literature over a range of equivalence ratios, pressures and reactant temperatures. A series of calculation were performed to assess the key parameters determining the flammability of hydrogen mixtures. Increased reactant temperature was found to greatly increase the flame speed and the flammability of the mixture. The effect of added diluents was assessed. Addition of water and carbon dioxide were found to reduce the flame speed and thus the flammability of a hydrogen mixture approximately equally well and much more than the addition of nitrogen. The detailed chemical kinetic model was used to explore the detonability of hydrogen mixtures. A Zeldovich-von Neumann-Doring (ZND) detonation model coupled with detailed chemical kinetics was used to model the detonation. The effectiveness on different diluents was assessed in reducing the detonability of a hydrogen mixture. Carbon dioxide was found to be most effective in reducing the detonability followed by water and nitrogen. The chemical …
Date: April 2, 2008
Creator: Pitz, W J & Westbrook, C K
Object Type: Report
System: The UNT Digital Library
A Single-band Cold Mass Support System for the MICE Superconducting Coupling Magnet (open access)

A Single-band Cold Mass Support System for the MICE Superconducting Coupling Magnet

The cooling channel of the Muon Ionization Cooling Experiment (MICE) consists of eighteen superconducting solenoid coils, which are magnetically hooked together and contained in seven modules. The operations of a pair of MICE superconducting coupling magnets are affected directly by the other solenoid coils in the MICE channel. In order to meet the stringent requirement for the magnet center and axis azimuthal angle at 4.2 K, a self-centered tension-band cold mass support system with intermediate thermal interruption was applied for the MICE superconducting coupling magnet. The physical center of the magnet does not change as it is cooled down from 300 K to 4.2 K using this support system. This paper analyzed and calculated force loads on the coupling magnet under various operation modes of the MICE cooling channel. The performance parameters of a single-band cold mass support system were calculated also.
Date: April 2, 2008
Creator: Wu, Hong; Wang, Li; Liu, X.K.; Liu, C.S.; Li, L.K.; Xu, Feng Yu et al.
Object Type: Article
System: The UNT Digital Library
Ultrabright Laser-based MeV-class Light Source (open access)

Ultrabright Laser-based MeV-class Light Source

We report first light from a novel, new source of 10-ps 0.776-MeV gamma-ray pulses known as T-REX (Thomson-Radiated Extreme X-rays). The MeV-class radiation produced by TREX is unique in the world with respect to its brightness, spectral purity, tunability, pulse duration and laser-like beam character. With T-REX, one can use photons to efficiently probe and excite the isotope-dependent resonant structure of atomic nucleus. This ability will be enabling to an entirely new class of isotope-specific, high resolution imaging and detection capabilities.
Date: April 2, 2008
Creator: Albert, F.; Anderson, G.; Anderson, S.; Bayramian, A.; Berry, B.; Betts, S. et al.
Object Type: Article
System: The UNT Digital Library
Relativistic Flows Using Spatial And Temporal Adaptive Structured Mesh Refinement. I. Hydrodynamics (open access)

Relativistic Flows Using Spatial And Temporal Adaptive Structured Mesh Refinement. I. Hydrodynamics

Astrophysical relativistic flow problems require high resolution three-dimensional numerical simulations. In this paper, we describe a new parallel three-dimensional code for simulations of special relativistic hydrodynamics (SRHD) using both spatially and temporally structured adaptive mesh refinement (AMR). We used method of lines to discrete SRHD equations spatially and used a total variation diminishing (TVD) Runge-Kutta scheme for time integration. For spatial reconstruction, we have implemented piecewise linear method (PLM), piecewise parabolic method (PPM), third order convex essentially non-oscillatory (CENO) and third and fifth order weighted essentially non-oscillatory (WENO) schemes. Flux is computed using either direct flux reconstruction or approximate Riemann solvers including HLL, modified Marquina flux, local Lax-Friedrichs flux formulas and HLLC. The AMR part of the code is built on top of the cosmological Eulerian AMR code enzo, which uses the Berger-Colella AMR algorithm and is parallel with dynamical load balancing using the widely available Message Passing Interface library. We discuss the coupling of the AMR framework with the relativistic solvers and show its performance on eleven test problems.
Date: April 2, 2007
Creator: Wang, Peng; Abel, Tom; Zhang, Weiqun & /KIPAC, Menlo Park
Object Type: Report
System: The UNT Digital Library
Summary of operations and performance of the Utica aquifer and North Lake Basin Wetlands restoration project in December 2006-November 2007. (open access)

Summary of operations and performance of the Utica aquifer and North Lake Basin Wetlands restoration project in December 2006-November 2007.

This document summarizes the performance of the groundwater restoration systems installed by the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) at the former CCC/USDA grain storage facility in Utica, Nebraska, during the third year of system operation, from December 1, 2006, until November 30, 2007. In the project at Utica, the CCC/USDA is cooperating with multiple state and federal agencies to remove carbon tetrachloride contamination from a shallow aquifer underlying the town and to provide supplemental treated groundwater for use in the restoration of a nearby wetlands area. Argonne National Laboratory has assisted the CCC/USDA by providing technical oversight for the aquifer restoration effort and facilities during this review period. This document presents overviews of the aquifer restoration facilities (Section 2) and system operations (Section 3), then describes groundwater production results (Section 4); groundwater treatment results (Section 5); and associated groundwater monitoring, system modifications, and costs during the review period (Section 6). Section 7 summarizes the present year of operation and provides some comparisons with system performance in previous years. The performance of the groundwater restoration systems at Utica in earlier years was summarized in greater detail previously (Argonne 2005, 2006).
Date: April 2, 2008
Creator: LaFreniere, L. M.
Object Type: Report
System: The UNT Digital Library
Self-Consistent 3D Modeling of Electron Cloud Dynamics and Beam Response (open access)

Self-Consistent 3D Modeling of Electron Cloud Dynamics and Beam Response

We present recent advances in the modeling of beam electron-cloud dynamics, including surface effects such as secondary electron emission, gas desorption, etc, and volumetric effects such as ionization of residual gas and charge-exchange reactions. Simulations for the HCX facility with the code WARP/POSINST will be described and their validity demonstrated by benchmarks against measurements. The code models a wide range of physical processes and uses a number of novel techniques, including a large-timestep electron mover that smoothly interpolates between direct orbit calculation and guiding-center drift equations, and a new computational technique, based on a Lorentz transformation to a moving frame, that allows the cost of a fully 3D simulation to be reduced to that of a quasi-static approximation.
Date: April 2, 2007
Creator: Furman, Miguel; Furman, M. A.; Celata, C. M.; Kireeff-Covo, M.; Sonnad, K. G.; Vay, J. L. et al.
Object Type: Article
System: The UNT Digital Library
Project Final Report Regional Forest-ABL Coupling: Influence on CO2 and Climate (open access)

Project Final Report Regional Forest-ABL Coupling: Influence on CO2 and Climate

Ecosystem CO{sub 2} exchange and atmospheric boundary layer (ABL) mixing are correlated diurnally and seasonally. Tracer transport models predict that these covariance signals produce a meridional gradient of annual mean CO{sub 2} concentration in the marine boundary layer that is half as strong as the signal produced by fossil fuel emissions. This rectifier effect has been predicted by many inversion models. However, observations to constrain the strength of the rectifier effect in nature are lacking. The fundamental objective of this project was to measure the strength of these covariance signals between ecosystem CO{sub 2} flux and ABL dynamics by employing ABL profiling systems at eddy flux tower sites. We found that (1) the observed diurnal and seasonal covariance between ecosystem CO{sub 2} fluxes and ABL turbulent mixing are strong; (2) the inversion model underestimates the diurnal and seasonal covariance; (3) the rectifier effect in the model appears to be too weak. However, these results are subject to significant uncertainties associated with the use of a point measurement to represent an area, fair weather bias among the data and instruments, and nonlinear transport processes between continental and marine boundary layers.
Date: April 2, 2003
Creator: Davis, Kenneth J. & Yi, Chuixiang
Object Type: Report
System: The UNT Digital Library
Low-Cost High-Pressure Hydrogen Generator (open access)

Low-Cost High-Pressure Hydrogen Generator

Electrolysis of water, particularly in conjunction with renewable energy sources, is potentially a cost-effective and environmentally friendly method of producing hydrogen at dispersed forecourt sites, such as automotive fueling stations. The primary feedstock for an electrolyzer is electricity, which could be produced by renewable sources such as wind or solar that do not produce carbon dioxide or other greenhouse gas emissions. However, state-of-the-art electrolyzer systems are not economically competitive for forecourt hydrogen production due to their high capital and operating costs, particularly the cost of the electricity used by the electrolyzer stack. In this project, Giner Electrochemical Systems, LLC (GES) developed a low cost, high efficiency proton-exchange membrane (PEM) electrolysis system for hydrogen production at moderate pressure (300 to 400 psig). The electrolyzer stack operates at differential pressure, with hydrogen produced at moderate pressure while oxygen is evolved at near-atmospheric pressure, reducing the cost of the water feed and oxygen handling subsystems. The project included basic research on catalysts and membranes to improve the efficiency of the electrolysis reaction as well as development of advanced materials and component fabrication methods to reduce the capital cost of the electrolyzer stack and system. The project culminated in delivery of a prototype electrolyzer …
Date: April 2, 2008
Creator: Cropley, Cecelia C. & Norman, Timothy J.
Object Type: Report
System: The UNT Digital Library
Gamma-Ray Imaging with Position-Sensitive HPGe detectors (open access)

Gamma-Ray Imaging with Position-Sensitive HPGe detectors

None
Date: April 2, 2004
Creator: Vetter, K.; Burks, M. & Mihailescu, L.
Object Type: Article
System: The UNT Digital Library
Effect of Electrode Composition and Microstructure on Impedancemetric Nitric Oxide Sensors based on YSZ Electrolyte (open access)

Effect of Electrode Composition and Microstructure on Impedancemetric Nitric Oxide Sensors based on YSZ Electrolyte

The role of metal (Au, Pt, and Ag) electrodes in YSZ electrolyte-based impedancemetric nitric oxide (NO) sensors is investigated using impedance spectroscopy and equivalent circuit analysis. The test cell consists of a rectangular block of porous YSZ with two metal wire loop electrodes, both exposed to the same atmosphere. Of the electrode materials, only Au was sensitive to changes in NO concentration. The impedance behavior of porous Au electrodes in a slightly different configuration was compared with dense Au electrodes and was also insensitive to NO. Ag showed no sensitivity to either O{sub 2} or NO, and the measured impedances occurred at frequencies > 10 kHz, which are typically associated with ionic conduction in YSZ. Pt and porous Au showed sensitivity to O{sub 2}, which was quantified using power-law exponents that suggest electrochemical rate-determining mechanisms occurring at the triple phase boundary. The behavior of the dense Au suggests different rate-determining processes (e.g., diffusion or adsorption) for the O{sub 2} reaction. Although the exact mechanism is not determined, the composition and microstructure of the metal electrode seem to alter the rate-limiting step of the interfering O{sub 2} reaction. Impedance behavior of the O{sub 2} reaction that is limited by processes occurring …
Date: April 2, 2007
Creator: Woo, L. Y.; Martin, L. P.; Glass, R. S.; Wang, W.; Jung, S.; Gorte, R. J. et al.
Object Type: Article
System: The UNT Digital Library
Sampling and Analysis Instruction for Borehole Sampling at 118-B-1 Burial Ground (open access)

Sampling and Analysis Instruction for Borehole Sampling at 118-B-1 Burial Ground

The Washington Closure Hanford (WCH) Field Remediation Project has removed all of the disposed materials and contaminated soil from the 118-B-1 Burial Ground with the exception of tritium-contaminated soil that is believed to extend from the bottom of the present excavation to groundwater and is believed to contribute to tritium contamination observed at down-gradient monitoring Well 199-B8-6. This sampling and analysis instruction (SAI) provides the requirements for sample collection and laboratory analysis for characterization of the vertical distribution of tritium contamination in the vadose zone soil below the 118-B-1 Burial Ground remedial action excavation.
Date: April 2, 2007
Creator: Thompson, W. S.
Object Type: Report
System: The UNT Digital Library
Design of Current Leads for the MICE Coupling Magnet (open access)

Design of Current Leads for the MICE Coupling Magnet

A pair of superconducting coupling magnets will be part of the Muon Ionization Cooling Experiment (MICE). They were designed and will be constructed by the Institute of Cryogenics and Superconductivity Technology, Harbin Institute of Technology, in collaboration with Lawrence Berkeley National Laboratory. The coupling magnet is to be cooled by using cryocoolers at 4.2K. In order to reduce the heat leak to the 4.2K cold mass from 300 K, a pair of current leads composed of conventional copper leads and high temperature superconductor (HTS) leads will be used to supply current to the magnet. This paper presents the optimization of the conventional conduction-cooled metal leads for the coupling magnet. Analyses on heat transfer down the leads using theoretical method and numerical simulation were carried out. The stray magnetic field around the HTS leads has been calculated and effects of the magnetic field on the performance of the HTS leads has also been analyzed.
Date: April 2, 2008
Creator: Wang, Li; Li, L.K.; Wu, Hong; Xu, Feng Yu; Liu, X.K.; Jia, Lin X. et al.
Object Type: Article
System: The UNT Digital Library