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Federal Radiological Monitoring and Assessment Center Phased Response Operations (open access)

Federal Radiological Monitoring and Assessment Center Phased Response Operations

A Federal Radiological Monitoring and Assessment Center (FRMAC) is established in response to the Lead Federal Agency (LFA) or state request when a major radiological emergency is anticipated of has occurred. The FRMAC becomes a coalition of federal off-site monitoring and assessment activities to assist the LFA, state(s), local, and tribal authorities. State, local, and tribal authorities are invited to co-locate and prioritize monitoring and assessment efforts in the FRMAC. The Department of Energy is tasked by the Federal Radiological Emergency Response Plan to coordinate the FRMAC.
Date: June 30, 1999
Creator: Riland, C. A. & Bowman, D. R.
System: The UNT Digital Library
Grazing incidence liquid metal mirrors (GILMM) for radiation hardened final optics for laser inertial fusion energy power plants (open access)

Grazing incidence liquid metal mirrors (GILMM) for radiation hardened final optics for laser inertial fusion energy power plants

A thin film of liquid metal is suggested as a grazing incident liquid metal mirror (GILMM) for robust final optics of a laser inertial fusion energy (IFE) power plant. The amount of laser light the mirror can withstand, called the damage limit, of a sodium film 85{sup o} from normal is calculated to be 57 J/cm{sup 2} normal to the beam for a 20 ns pulse and 1.3 J/cm{sup 2} for a 10 ps pulse of 0.35 {micro}m light (2 m{sup 2} and 90 m{sup 2} of mirror area per 100 kJ of laser energy at 20 ns and 10 ps, respectively). Feasibility relies on keep the liquid surface flat to the required accuracy by a combination of polished substrate, adaptive (deformable) optics, surface tension and low Reynolds number, laminar flow in the film. The film's substrate must be polished to {+-} 0.015 pm. Then surface tension keeps the surface smooth over short distances (<10 mm) and low Reynolds number laminar flow keeps the surface smooth by keeping the film thickness constant to less than + 0.01 w over long distance >10 mm. Adaptive optics techniques keep. the substrate flat to within {+-} 0.06 pm over 100 mm distance and …
Date: June 30, 1999
Creator: Moir, R W
System: The UNT Digital Library
Measurements of Large Scale-Length Plasmas Produced From Gas-Filled Targets (open access)

Measurements of Large Scale-Length Plasmas Produced From Gas-Filled Targets

Apart from their intrinsic interest, plasma physics processes are important because they affect the coupling of the laser energy into laser-irradiated targets. Recently, new gas-filled targets have been developed to create large mm-size plasmas for the study of stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS). We present x-ray images and x-ray spectra to characterize these targets, which show that the plasmas are homogeneous, have electron densities of {approximately}10{sup 21} cm{sup {minus}3}, and attain electron temperatures of {approximately}3 keV. We also present SBS measurements to demonstrate how systematic studies of physical phenomena can be performed using these targets.
Date: June 30, 1995
Creator: Back, C. A.; Berger, R. L. & Estabrook, K.
System: The UNT Digital Library
Integrated power conditioning for laser diode arrays (open access)

Integrated power conditioning for laser diode arrays

This compact modulator has demonstated its ability to efficiently and accurately drive a laser diode array. The addition of the crowbar protection circuit is an invaluable addition to the integrated system and is capable of protecting the laser diode array against severe damage. We showed that the correlation between measured data and simulation indicates that our modulator model is valid and can be used as a tool in the design of future systems. The spectrometer measurements that we conducted underline the imprtance of current regulation to stable laser operation.
Date: June 30, 1995
Creator: Hanks, R. L.; Kirbie, H. C.; Newton, M. A. & Farhoud, M. S.
System: The UNT Digital Library
Upgrades to the LLNL flash x-ray induction linear accelerator (FXR) (open access)

Upgrades to the LLNL flash x-ray induction linear accelerator (FXR)

The FXR is an induction linear accelerator used for flash radiography at the Lawrence Livermore National Laboratory's Site 300 Test Facility. The FXR was originally completed in 1982 and has been in continuous use as a radiographic tool. At that time the FXR produced a 17MeV, 2.2 kA burst of electrons for a duration of 65 ns. An upgrade of the FXR was recently completed. The purpose of this upgrade was to improve the performance of the FXR by increasing the energy of the electron injector from 1.2 MeV to 2.5 MeV and the beam current from 2.2 kA to 3 kA, improving the magnetic transport system by redesigning the solenoidal transport focus coils, reducing the rf coupling of the electron beam to the accelerator cells, and by adding additional beam diagnostics. We will describe the injector upgrades and performance as well as our efforts to tune the accelerator by minimizing beam corkscrew motion and the impact of Beam Breakup Instability on beam centroid motion throughout the beam line as the current is increased to 3 kA.
Date: June 30, 1997
Creator: Scarpetti, R. D., LLNL
System: The UNT Digital Library
Initial statistical evaluation of ARAC COAMPS forecasts (open access)

Initial statistical evaluation of ARAC COAMPS forecasts

This informal workshop was organized to bring together scientists and engineers from St0 and LLNL with a common interest in using and developing new in-situ measurement techniques for studying the coastal ocean, particularly near-surface waters in the biologically active photic layer. Much of the discussion focused on the current and potential capabilities of the LLNL ''IMEEDS'' ocean observation capability (Integrated Marine Environmental Element Detection System), and ways to complement and process the data that can be obtained from the system. Two important goals of the workshop were to identify the range of current activities that could be usefully integrated with the capabilities of the LLNL system, and to explore additional scientific problems of the coastal ocean that could be addressed through collaborative LLNL - SIO efforts. A short summary of the issues addressed follows, with lead discussants identified. A series of action items developed during the course of the workshop, a list of participants, and a conference agenda conclude this report.
Date: June 30, 1999
Creator: Pace, J. C.
System: The UNT Digital Library
Identification of an incommensurate FeAl{sub 2} overlayer on FeAl(110) using x-ray diffraction and reflectivity (open access)

Identification of an incommensurate FeAl{sub 2} overlayer on FeAl(110) using x-ray diffraction and reflectivity

FeAl, like NiAl, crystallizes in the CsCl structure. Consequently the (110) planes contain equal amounts of Fe and Al distributed as interlocking rectangles. Unlike the NiAI(110) surface, which retains the (1{times}l) in-plane symmetry of the bulk, FeAl(l10) reconstructs to form an ordered, incommensurate overlayer. The reconstructed layer introduces x-ray diffraction rods at half-order positions along the [1{bar 1}0] direction, and displaced {plus_minus}0.2905 from integer positions along the [001] direction. Peak widths reveal excellent long range order. Specular reflectivity measurements above and below the Fe K{alpha} edge can be reproduced using a model containing a single reconstructed overlayer with an Fe:Al ratio of 1:2, consistent with FeA{sub I}2.
Date: June 30, 1995
Creator: Baddorf, A. P. & Chandavarkar, S. S.
System: The UNT Digital Library
Thermal recovery of the NIF amplifiers (open access)

Thermal recovery of the NIF amplifiers

With approximately 99% of the electrical energy supplied to the National Ignition Facility (NIF) appearing as heat in the amplifiers, thermal recovery of the NIF system is a major consideration in the design process. The NIF shot rate is one shot every 8 hours, with a goal of 4 hours between shots. This necessitates that thermal recovery take place in no more than 7 hours, with a goal of 3 hours for the accelerated shot rate. Residual optical distortions, which restrict the shot rate, are grouped into two discrete categories: (1) distortions associated with residual temperature gradients in the laser slabs, and (2) distortions associated with buoyantly driven convective currents in the amplifier cavity and beam-tube regions. Thermal recovery of the amplifiers is achieved by cooling the flashlamps and blastshields with a turbulent gas flow. The cooled blastshields then serve as a cold boundary to radiatively extract the residual heat deposited in the slabs and edge claddings. Advanced concepts, such as the use of slightly chilled gas to accelerate some aspects of recovery, are addressed. To quantify recovery rates of the amplifiers, experiments and numerical models are used to measure and calculate the temperatures and optical distortions in NIF-like amplifier …
Date: June 30, 1998
Creator: Beullier, J.; Bicrel,; Erlandson, A.; London, R.; Manes, K.; Marshall, C. et al.
System: The UNT Digital Library
Plasma electrode pockels cell for the National Ignition Facility (open access)

Plasma electrode pockels cell for the National Ignition Facility

The National Ignition Facility (NIF), now under construction at Lawrence Livermore National Laboratory, will be the largest laser fusion facility ever built. The NIF laser architecture is based on a multi-pass power amplifier to reduce cost and maximize performance. A key component in this laser design is an optical switch that closes to trap the optical pulse in the cavity for four gain passes and then opens to divert the optical pulse out of the amplifier cavity. The switch is comprised of a Pockels cell and a polarizer and is unique because it handles a beam that is 40 cm x 40 cm square and allows close horizontal and vertical beam spacing. Conventional Pockels cells do not scale to such large apertures or the square shape required for close packing. Our switch is based on a Plasma-Electrode Pockels Cell (PEPC). In a PEPC, low-pressure helium discharges (l-2 kA) are formed on both sides of a thin slab of electro-optic material. Typically, we use KH2P04 crystals (KDP). The discharges form highly conductive, transparent sheets that allow uniform application of a high-voltage pulse (17 kV) across the crystal. A 37 cm x 37 cm PEPC has been in routine operation for two …
Date: June 30, 1998
Creator: Biltoft, P.; Fochs, S. & Rhodes, M. A.
System: The UNT Digital Library
Two-color mid-infrared thermometer using a hollow glass optical fiber (open access)

Two-color mid-infrared thermometer using a hollow glass optical fiber

A non-invasive two-color infrared thermometer has been developed for low-temperature biomedical applications. Mid-infrared radiation from the target is collected via a single 700 {mu}m-bore hollow glass optical fiber, simultaneously split into two paths and modulated by a gold-coated reflective optical chopper, and focused onto two thermoelectrically-cooled HgCdZnTe photoconductors (bandpasses of 2- 6 {mu}m and 2-12 {mu}m, respectively) by gold-coated spherical mirrors. The small numerical aperture of the hollow glass fiber provides high spatial resolution (is less than 1 mm), and the hollow bore eliminates reflective losses. The modulated detector signals are recovered using lock-in amplification, permitting measurement of small low-temperature signal buried in the background. A computer algorithm calculates the true temperature and emissivity of the target in real time based on a previous blackbody (emissivity equal to 1) calibration, taking into account reflection of the ambient radiation field from the target surface.
Date: June 30, 1997
Creator: Small, W., IV; Celliers, P. M.; Da Silva, L. D. & Matthews, D. L.
System: The UNT Digital Library
Low-profile high-voltage compact gas switch (open access)

Low-profile high-voltage compact gas switch

This paper discusses the development and testing of a low-profile, high-voltage, spark-gap switch designed to be closely coupled with other components into an integrated high-energy pulsed-power source. The switch is designed to operate at 100 kV using SF6 gas pressurized to less than 0.7 MPa. The volume of the switch cavity region is less than 1.5 cm3, and the field stress along the gas-dielectric interface is as high as 130 kV/cm. The dielectric switch body has a low profile that is only I -cm tall at its greatest extent and nominally 2-mm thick over most of its area. This design achieves a very low inductance of less than 5 nH, but results in field stresses exceeding 500 kV/cm in the dielectric material. Field modeling was done to determine the appropriate shape for the highly stressed insulator and electrodes, and special manufacturing techniques were employed to mitigate the usual mechanisms that induce breakdown and failure in solid dielectrics. Static breakdown tests verified that the switch operates satisfactorily at 100 kV levels. The unit has been characterized with different shaped electrodes having nominal gap spacings of 2.0, 2.5, and 3.0 mm. The relationship between self-break voltage and operating pressure agrees well with …
Date: June 30, 1997
Creator: Goerz, D. A.; Wilson, M. J. & Speer, R. D.
System: The UNT Digital Library
Excess cross-sections at the electroweak scale in the sextet quark {open_quotes}standard model{close_quotes} (open access)

Excess cross-sections at the electroweak scale in the sextet quark {open_quotes}standard model{close_quotes}

If dynamical electroweak symmetry breaking is due to a flavor doublet of color sextet quarks, enhanced electroweak scale QCD instanton interactions may produce a large top mass, raise the {eta}{sub 6} axion mass, and also explain the excesses in the DIS cross-section at HERA and jet cross-sections at the Tevatron.
Date: June 30, 1997
Creator: White, A.R.
System: The UNT Digital Library
Spectral ellipsometry of GaSb and GaInAsSb: Experiment and modeling (open access)

Spectral ellipsometry of GaSb and GaInAsSb: Experiment and modeling

The optical constants {epsilon}(E)[={epsilon}{sub 1}(E)+i{epsilon}{sub 2}(E)] of single-crystal GaSb at 300K have been measured using spectral ellipsometry in the range of 0.3-5.3 eV. The {epsilon}(E) spectra displayed distinct structures associated with critical points (CPs) at E{sub 0} (direct gap), spin-orbit split E{sub 0}+{Delta}{sub 0} component, spin-orbit split (E{sub 1}, E{sub 1}+{Delta}{sub 1}) and (E{sub 0}{prime}, E{sub 0}{prime}+{Delta}{sub 0}{prime}) doublets, as well as E{sub 2}. The experimental data over the entire measured spectral range (after oxide removal) has been fit using the Holden model dielectric function based on the electronic energy-band structure near these CPs plus excitonic and band-to-band Coulomb enhancement effects at E{sub 0}, E{sub 0}+{Delta}{sub 0} and the E{sub 1}, E{sub 1}+{Delta}{sub 1} doublet. In addition to evaluating the energies of these various band-to-band CPs, information about the binding energy (R{sub 1}) of the two-dimensional exciton related to the E{sub 1}, E{sub 1}+{Delta}{sub 1} CPs was obtained. The value of R{sub 1} was in good agreement with effective mass/k{sup {rightharpoonup}}{center_dot}p{sup {rightharpoonup}} theory. The ability to evaluate R{sub 1} has important ramifications for recent first-principles band structure calculations which include exciton effects at E{sub 0}, E{sub 1}, and E{sub 2}. The experimental results were compared to other evaluations of the …
Date: June 30, 1999
Creator: Charache, G.W.; Mu {tilde n}oz, M.; Wei, K.; Pollak, F.H. & Freeouf, J.L.
System: The UNT Digital Library
Coupling 2-D cylindrical and 3-D x-y-z transport computations (open access)

Coupling 2-D cylindrical and 3-D x-y-z transport computations

This paper describes a new two-dimensional (2-D) cylindrical geometry to three-dimensional (3-D) rectangular x-y-z splice option for multi-dimensional discrete ordinates solutions to the neutron (photon) transport equation. Of particular interest are the simple transformations developed and applied in order to carry out the required spatial and angular interpolations. The spatial interpolations are linear and equivalent to those applied elsewhere. The angular interpolations are based on a high order spherical harmonics representation of the angular flux. Advantages of the current angular interpolations over previous work are discussed. An application to an intricate streaming problem is provided to demonstrate the advantages of the new method for efficient and accurate prediction of particle behavior in complex geometries.
Date: June 30, 1998
Creator: Abu-Shumays, I. K.; Yehnert, C. E. & Pitcairn, T. N.
System: The UNT Digital Library
Unsupervised hyperspectral image analysis using independent component analysis (ICA) (open access)

Unsupervised hyperspectral image analysis using independent component analysis (ICA)

In this paper, an ICA-based approach is proposed for hyperspectral image analysis. It can be viewed as a random version of the commonly used linear spectral mixture analysis, in which the abundance fractions in a linear mixture model are considered to be unknown independent signal sources. It does not require the full rank of the separating matrix or orthogonality as most ICA methods do. More importantly, the learning algorithm is designed based on the independency of the material abundance vector rather than the independency of the separating matrix generally used to constrain the standard ICA. As a result, the designed learning algorithm is able to converge to non-orthogonal independent components. This is particularly useful in hyperspectral image analysis since many materials extracted from a hyperspectral image may have similar spectral signatures and may not be orthogonal. The AVIRIS experiments have demonstrated that the proposed ICA provides an effective unsupervised technique for hyperspectral image classification.
Date: June 30, 2000
Creator: Chiang, S. S. & Ginsberg, I. W.
System: The UNT Digital Library
A linear mixture analysis-based compression for hyperspectral image analysis (open access)

A linear mixture analysis-based compression for hyperspectral image analysis

In this paper, the authors present a fully constrained least squares linear spectral mixture analysis-based compression technique for hyperspectral image analysis, particularly, target detection and classification. Unlike most compression techniques that directly deal with image gray levels, the proposed compression approach generates the abundance fractional images of potential targets present in an image scene and then encodes these fractional images so as to achieve data compression. Since the vital information used for image analysis is generally preserved and retained in the abundance fractional images, the loss of information may have very little impact on image analysis. In some occasions, it even improves analysis performance. Airborne visible infrared imaging spectrometer (AVIRIS) data experiments demonstrate that it can effectively detect and classify targets while achieving very high compression ratios.
Date: June 30, 2000
Creator: Chang, C. I. & Ginsberg, I. W.
System: The UNT Digital Library
Evaluating intensified camera systems (open access)

Evaluating intensified camera systems

This paper describes image evaluation techniques used to standardize camera system characterizations. The authors group is involved with building and fielding several types of camera systems. Camera types include gated intensified cameras, multi-frame cameras, and streak cameras. Applications range from X-ray radiography to visible and infrared imaging. Key areas of performance include sensitivity, noise, and resolution. This team has developed an analysis tool, in the form of image processing software, to aid an experimenter in measuring a set of performance metrics for their camera system. These performance parameters are used to identify a camera system's capabilities and limitations while establishing a means for camera system comparisons. The analysis tool is used to evaluate digital images normally recorded with CCD cameras. Electro-optical components provide fast shuttering and/or optical gain to camera systems. Camera systems incorporate a variety of electro-optical components such as microchannel plate (MCP) or proximity focused diode (PFD) image intensifiers; electro-static image tubes; or electron-bombarded (EB) CCDs. It is often valuable to evaluate the performance of an intensified camera in order to determine if a particular system meets experimental requirements.
Date: June 30, 2000
Creator: Baker, S. A.
System: The UNT Digital Library
Fault current limiter-predominantly resistive behavior of a BSCCO shielded-core reactor (open access)

Fault current limiter-predominantly resistive behavior of a BSCCO shielded-core reactor

Tests were conducted to determine the electrical and magnetic characteristics of a superconductor shielded core reactor (SSCR). The results show that a closed-core SSCR is predominantly a resistive device and an open-core SSCR is a hybrid resistive/inductive device. The open-core SSCR appears to dissipate less than the closed-core SSCR. However, the impedance of the open-core SSCR is less than that of the closed-core SSCR. Magnetic and thermal diffusion are believed to be the mechanism that facilitates the penetration of the superconductor tube under fault conditions.
Date: June 30, 2000
Creator: Ennis, M. G.; Tobin, T. J.; Cha, Y. S. & Hull, J. R.
System: The UNT Digital Library
FACET: an object-oriented software framework for modeling complex social behavior patterns (open access)

FACET: an object-oriented software framework for modeling complex social behavior patterns

The Framework for Addressing Cooperative Extended Transactions (FACET) is a flexible, object-oriented architecture for implementing models of dynamic behavior of multiple individuals, or agents, in a simulation. These agents can be human (individuals or organizations) or animal and may exhibit any type of organized social behavior that can be logically articulated. FACET was developed by Argonne National Laboratory's (ANL) Decision and Information Sciences Division (DIS) out of the need to integrate societal processes into natural system simulations. The FACET architecture includes generic software components that provide the agents with various mechanisms for interaction, such as step sequencing and logic, resource management, conflict resolution, and preemptive event handling. FACET components provide a rich environment within which patterns of behavior can be captured in a highly expressive manner. Interactions among agents in FACET are represented by Course of Action (COA) object-based models. Each COA contains a directed graph of individual actions, which represents any known pattern of social behavior. The agents' behavior in a FACET COA, in turn, influences the natural landscape objects in a simulation (i.e., vegetation, soil, and habitat) by updating their states. The modular design of the FACET architecture provides the flexibility to create multiple and varied simulation scenarios …
Date: June 30, 2000
Creator: Dolph, J. E.; Christiansen, J. H. & Sydelko, P. J.
System: The UNT Digital Library
U1h shaft project (open access)

U1h shaft project

The U1h shaft project is a design/build subcontract to construct one 20 foot (ft) finished diameter shaft to a depth of 1,045 ft at the Nevada Test Site. Atkinson Construction was subcontracted by Bechtel Nevada to construct the U1h Shaft for the Department of Energy. The project consists of furnishing and installing the sinking plant, construction of the 1,045 ft of concrete lined shaft, development of a shaft station at a depth of 976 ft, and construction of a loading pocket at the station. The outfitting of the shaft and installation of a new hoist may be incorporated into the project at a later date. This paper should be of interest to those involved with the construction of relatively deep shafts and underground excavations.
Date: June 30, 2000
Creator: Briggs, Brian & Musick, R. G.
System: The UNT Digital Library
Biodiversity analysis of vegetation on the Nevada Test Site (open access)

Biodiversity analysis of vegetation on the Nevada Test Site

The Nevada Test Site (NTS), located in south-central Nevada, encompasses approximately 3,500 square kilometers and straddles two major North American deserts, Mojave and Great Basin. Transitional areas between the two desert types have been created by gradients in elevation, precipitation, temperature, and soils. From 1996 to 1998, more than 1,500 ecological landform units were sampled at the NTS for numerous biotic and abiotic parameters. The data provide a basis for spatial evaluations of biodiversity over landscape scales at the NTS. Biodiversity maps (species richness vs. species abundance) have been produced. Differences in biodiversity among ecoregions and vegetation alliances are presented. Spatial distribution maps of species' presence and abundance provide evidence of where transition zones occur and the resulting impact on biodiversity. The influences of abiotic factors, such as elevation, soil, and precipitation, on biodiversity are assessed.
Date: June 30, 2000
Creator: Ostler, W. K. & Hansen, D. J.
System: The UNT Digital Library
Engineered covers for mud pit closures Central Nevada Test Area, Nevada (open access)

Engineered covers for mud pit closures Central Nevada Test Area, Nevada

Two abandoned drilling mud pits impacted with petroleum hydrocarbons were determined to require closure action at the Central Nevada Test Area. The UC-4 Mud Pit C is approximately 0.12 hectares (0.3 acres) and 1.2 meters (4 feet) in depth. The UC-1 Central Mud Pit (CMP) is approximately 1.54 hectares (3.8 acres) and 2.4 meters (8 feet) in depth. Both mud pits contain bentonite drilling muds with a thin dry crust, low shear strength, low permeability, and high moisture content. The following closure methodologies were evaluated: stabilization by mixing/injection with soil, fly ash, and lime; excavation and disposal; on-site drying; thermal destruction; wick drains; administrative closure (postings and land-use restrictions); and engineered covers. Based upon regulatory closure criteria, implementation, and cost considerations, the selected remedial alternative was the construction of an engineered cover. A multilayered cover with a geo-grid and geo-synthetic clay liner (GCL) was designed and constructed over the UC-4 Mud Pit C to evaluate the constructability and applicability of the design for the CMP cover. The geo-grid provided structural strength for equipment and material loads during cover construction, and the GCL was used as a moisture infiltration barrier. The design was determined to be constructable and applicable. To reduce …
Date: June 30, 2000
Creator: Madsen, D. D.
System: The UNT Digital Library
Low Loss Rapid Cycling Synchrotron Design for the Spallation Neutron Source. (open access)

Low Loss Rapid Cycling Synchrotron Design for the Spallation Neutron Source.

None
Date: June 30, 2000
Creator: Wei, J.; Beebe-Wang, J.; Blaskiewicz, M.; Brennan, M.; Cameron, P.; Catalan-Lasheras, N. et al.
System: The UNT Digital Library
FODO/Doublet Lattice for the SNS Accumulator Ring. (open access)

FODO/Doublet Lattice for the SNS Accumulator Ring.

Requirements of minimum beam loss for hand-on maintenance and flexibility for future operations are essential for the lattice design of the Spallation Neutron Source (SNS) accumulator ring. In this paper, we present a hybrid lattice that consists of FODO arcs and doublet straights, emphasizing injection and collimation optimization and flexibility, split tunes for coupling control, sextupole families for chromaticity control, and compatibility to future upgrades.
Date: June 30, 2000
Creator: Wei, J.; Gardner, C.; Lee, Y. Y. & Tsoupas, N.
System: The UNT Digital Library