Mechanical design of a high field common coil magnet (open access)

Mechanical design of a high field common coil magnet

A common coil design for high field 2-in-1 accelerator magnets has been previously presented as a 'conductor-friendly' option for high field magnets applicable for a Very Large Hadron Collider. This paper presents the mechanical design for a 14 tesla 2-in-1 dipole based on the common coil design approach. The magnet will use a high current density Nb{sub 3}Sn conductor. The design addresses mechanical issues particular to the common coil geometry: horizontal support against coil edges, vertical preload on coil faces, end loading and support, and coil stresses and strains. The magnet is the second in a series of racetrack coil magnets that will provide experimental verification of the common coil design approach.
Date: March 18, 1999
Creator: Caspi, S.; Chow, K.; Dietderich, D.; Gourlay, S.; Gupta, R.; McInturff, A. et al.
Object Type: Article
System: The UNT Digital Library
STRUCTURAL CALCULATIONS FOR THE LIFTING IN VERTICAL ORIENTATION OF 5-DHLW/DOE SNF SINGLE CRM WASTE PACKAGES (open access)

STRUCTURAL CALCULATIONS FOR THE LIFTING IN VERTICAL ORIENTATION OF 5-DHLW/DOE SNF SINGLE CRM WASTE PACKAGES

None
Date: October 18, 1999
Creator: Mastilovic, S.
Object Type: Report
System: The UNT Digital Library
Enhanced Geothermal Systems (EGS) R&D Program (open access)

Enhanced Geothermal Systems (EGS) R&D Program

The purpose of this workshop was to develop technical background facts necessary for planning continued research and development of Enhanced Geothermal Systems (EGS). EGS are geothermal reservoirs that require improvement of their permeability or fluid contents in order to achieve economic energy production. The initial focus of this R&D program is devising and testing means to extract additional economic energy from marginal volumes of hydrothermal reservoirs that are already producing commercial energy. By mid-1999, the evolution of the EGS R&D Program, begun in FY 1988 by the U.S. Department of Energy (DOE), reached the stage where considerable expertise had to be brought to bear on what technical goals should be pursued. The main purpose of this Workshop was to do that. The Workshop was sponsored by the Office of Geothermal Technologies of the Department of Energy. Its purpose and timing were endorsed by the EGS National Coordinating Committee, through which the EGS R&D Program receives guidance from members of the U.S. geothermal industry. Section 1.0 of this report documents the EGS R&D Program Review Session. There, managers and researchers described the goals and activities of the program. Recent experience with injection at The Geysers and analysis of downhole conditions at …
Date: August 18, 1999
Creator: Entingh, Daniel J.
Object Type: Article
System: The UNT Digital Library
Comparisons of cloud cover and cloud fractions using remote-sensing retrievals (open access)

Comparisons of cloud cover and cloud fractions using remote-sensing retrievals

The DOE's Atmospheric Radiation Measurement (ARM) Program employs both upward- and downward-looking remote-sensing instruments to measure the horizontal and vertical distributions of clouds across its Southern Great Plains (SGP) site. No single instrument is capable of completely determining these distributions over the scales of interest to ARM's Single Column Modeling (SCM) and Instantaneous Radiative Flux (IRF) groups; these groups embody the primary strategies through which ARM expects to achieve its objectives of developing and testing cloud formation (USDOE, 1996). Collectively, however, the data from ARM's cloud-detecting instruments offer the potential for such a three-dimensional characterization. Data intercomparisons, like the ones illustrated here, are steps in this direction. Specifically, they are valuable because they help: provide a measure of uncertainty in ARM's measurement capabilities, calibrate retrieval methods and refine algorithms and concepts. In the process, we are forced to think of meaningful ways in which measurements from different instruments can be compared and, perhaps, combined. While the ultimate goal of this particular effort is to develop the ability to accurately characterize cloud fields in three dimensions over time at the SGP site, along the way we will address such questions as ''which source, or combination of cloud data sources, offers a …
Date: May 18, 1999
Creator: Krueger, S K & Rodriguez, D
Object Type: Report
System: The UNT Digital Library
COAL CONVERSION WASTEWATER TREATMENT BY CATALYTIC OXIDATION IN SUPERCRITICAL WATER (open access)

COAL CONVERSION WASTEWATER TREATMENT BY CATALYTIC OXIDATION IN SUPERCRITICAL WATER

Wastewaters from coal-conversion processes contain phenolic compounds in appreciable concentrations. These compounds need to be removed so that the water can be discharged or re-used. Catalytic oxidation in supercritical water is one potential means of treating coal-conversion wastewaters, and this project examined the reactions of phenol over different heterogeneous oxidation catalysts in supercritical water. More specifically, we examined the oxidation of phenol over a commercial catalyst and over bulk MnO{sub 2}, bulk TiO{sub 2}, and CuO supported on Al{sub 2} O{sub 3}. We used phenol as the model pollutant because it is ubiquitous in coal-conversion wastewaters and there is a large database for non-catalytic supercritical water oxidation (SCWO) with which we can contrast results from catalytic SCWO. The overall objective of this research project is to obtain the reaction engineering information required to evaluate the utility of catalytic supercritical water oxidation for treating wastes arising from coal conversion processes. All four materials were active for catalytic supercritical water oxidation. Indeed, all four materials produced phenol conversions and CO{sub 2} yields in excess of those obtained from purely homogeneous, uncatalyzed oxidation reactions. The commercial catalyst was so active that we could not reliably measure reaction rates that were not limited by …
Date: October 18, 1999
Creator: Savage, Phillip E.
Object Type: Report
System: The UNT Digital Library
Radioactive air emissions notice of construction use of a portable exhauster on single shell tanks (SSTs) during salt well pumping (open access)

Radioactive air emissions notice of construction use of a portable exhauster on single shell tanks (SSTs) during salt well pumping

This document serves as a notice of construction (NOC), pursuant to the requirements of Washington Administrative Code (WAC) 246-247-060, and as a request for approval to construct, pursuant to 40 Code of Federal Regulations (CFR) 61.07, portable exhausters for use on single-shell tanks (SSTs) during salt well pumping. Table 1-1 lists 18 SSTs covered by this NOC. This NOC also addresses other activities that are performed in support of salt well pumping but do not require the application of a portable exhauster. Specifically this NOC analyzes the following three activities that have the potential for emissions. (1) Salt well pumping (i.e., the actual transferring of waste from one tank to another) under nominal tank operating conditions. Nominal tank operating conditions include existing passive breathing rates. (2) Salt well pumping (the actual transferring of waste from one tank to another) with use of a portable exhauster. (3) Use of a water lance on the waste to facilitate salt well screen and salt well jet pump installation into the waste. This activity is to be performed under nominal (existing passive breathing rates) tank operating conditions. The use of portable exhausters represents a cost savings because one portable exhauster can be moved back …
Date: November 18, 1999
Creator: GRANDO, C.J.
Object Type: Report
System: The UNT Digital Library
Oxidation Reactions of Ethane over Ba-Ce-O Based Perovskites (open access)

Oxidation Reactions of Ethane over Ba-Ce-O Based Perovskites

Ethane oxidation reactions were studied over pure and Ca-, Mg-, Sr-, La-, Nd-, and Y-substituted BaCeO{sub 3} perovskites under oxygen limited conditions. Several of the materials, notably the Ca- and Y-substituted materials, show activity for complete oxidation of the hydrocarbon to CO{sub 2} at temperatures below 650 C. At higher temperatures, the oxidative dehydrogenation (ODH) to ethylene becomes significant. Conversions and ethylene yields are enhanced by the perovskites above the thermal reaction in our system in some cases. The perovskite structure is not retained in the high temperature reaction environment. Rather, a mixture of carbonates and oxides is formed. Loss of the perovskite structure correlates with a loss of activity and selectivity to ethylene.
Date: August 18, 1999
Creator: Miller, James E.; Sault, Allen G.; Trudell, Daniel E.; Nenoff, Tina M.; Thoma, Steven G. & Jackson, Nancy B.
Object Type: Article
System: The UNT Digital Library
A machining parameter study to select best conditions for SPDT of large single-crystal silicon optics (open access)

A machining parameter study to select best conditions for SPDT of large single-crystal silicon optics

The interdependence of process parameters on diamond turning of single-crystal silicon is poorly understood. An experimental design technique based on methods of statistical analysis permits the determination of a specific parameter's influence and its co-dependence on other factors. This design technique enables the creation of an experimental matrix, considering all input parameters (surface velocity; feed rate; depth of cut; tool radius; tool rake/skew angle; cutting fluid), while substantially decreasing the overall number of experiments. After an initial survey the significant parameters for a subsequent response surface methodology (RSM) study can be selected. From measurements of tool wear, surface finish and sub-surface damage (SSD) the optimum parameter settings for the diamond turning process can then be determined.
Date: March 18, 1999
Creator: Carr, J W; Davis, P J; Haack, J K; Krulewich, D A; McClellan, M R & Zimmermann, M
Object Type: Article
System: The UNT Digital Library
Projected Consequence for Potential Sabotage Events Related to Spent Fuel Shipments (open access)

Projected Consequence for Potential Sabotage Events Related to Spent Fuel Shipments

There is a growing interest in understanding the potential consequences of malevolent acts against shipments of nuclear waste and/or material. Recently, Sandia National Laboratories (SNL) conducted a study' to evaluate the potential source terms available for release in a sabotage event for spent fuel shipments. Using these source terms, we developed an approach to assess the potential radiological consequences of the hypothesized events and to compare them to consequences of transportation accidents involving the same types of shipments. Our analysis showed that there could be orders of magnitude differences in consequence for urban, suburban, and rural events. Sabotage consequences could be orders of magnitude higher than those of transportation accidents with a probability of 10{sup {minus}12} or higher and be similar to events with a probability less than 10{sup {minus}12}. Also, explosive-induced buoyancy would disperse the source further out than a non-buoyant release in a transportation accident, which, therefore, would have a higher dose near the release point.
Date: August 18, 1999
Creator: Shyr, Lih-Jenn; Neuhauser, Sieglinde; Mills, Scott & Massey, Charles
Object Type: Article
System: The UNT Digital Library
Optimization of Micromachined Photon Devices (open access)

Optimization of Micromachined Photon Devices

The Oak Ridge National Laboratory has been instrumental in developing ultraprecision technologies for the fabrication of optical devices. We are currently extending our ultraprecision capabilities to the design, fabrication, and testing of micro-optics and MEMS devices. Techniques have been developed in our lab for fabricating micro-devices using single point diamond turning and ion milling. The devices we fabricated can be used in micro-scale interferometry, micro-positioners, micro-mirrors, and chemical sensors. In this paper, we focus on the optimization of microstructure performance using finite element analysis and the experimental validation of those results. We also discuss the fabrication of such structures and the optical testing of the devices. The performance is simulated using finite element analysis to optimize geometric and material parameters. The parameters we studied include bimaterial coating thickness effects; device length, width, and thickness effects, as well as changes in the geometry itself. This optimization results in increased sensitivity of these structures to absorbed incoming energy, which is important for photon detection or micro-mirror actuation. We have investigated and tested multiple geometries. The devices were fabricated using focused ion beam milling, and their response was measured using a chopped photon source and laser triangulation techniques. Our results are presented and …
Date: July 18, 1999
Creator: Datskos, P. G.; Datskou, I.; Evans, B. M., III & Rajic, S.
Object Type: Article
System: The UNT Digital Library
Combustion of TNT products in a confined explosion (open access)

Combustion of TNT products in a confined explosion

The effects of turbulent combustion of detonation products gases in a confined explosion are explored via laboratory experiments and high-resolution numerical simulations. The expanded products from the detonation of a TNT charge are rich in C and CO, which act as a fuel. When these hot gases mix with air, they are oxidized to CO2--thereby releasing 2482 Cal/g in addition to the 1093 Cal/g deposited by the detonation wave. In this case, the exothermic power is controlled by the turbulent mixing rate, rather than by chemistry. A kinetic law of turbulent combustion is suggested for this process. Pressure histories from the numerical simulations were in good agreement with the experimental measurements--demonstrating that the numerical model contains the fundamental mechanism that controls the exothermic process.
Date: June 18, 1999
Creator: Ferguson, R E; Kuhl, A L & Oppenheim, A K
Object Type: Article
System: The UNT Digital Library
Carbon Sequestered, Carbon Displaced and the Kyoto Context (open access)

Carbon Sequestered, Carbon Displaced and the Kyoto Context

The integrated system that embraces forest management, forest products, and land-use change impacts the global carbon cycle - and hence the net emission of the greenhouse gas carbon dioxide - in four fundamental ways. Carbon is stored in living and dead biomass, carbon is stored in wood products and landfills, forest products substitute in the market place for products made from other materials, and forest harvests can be used wholly or partially to displace fossil fuels in the energy sector. Implementation of the Kyoto Protocol to the United Nations Framework Convention on Climate Change would result in the creation of international markets for carbon dioxide emissions credits, but the current Kyoto text does not treat all carbon identically. We have developed a carbon accounting model, GORCAM, to examine a variety of scenarios for land management and the production of forest products. In this paper we explore, for two simple scenarios of forest management, the carbon flows that occur and how these might be accounted for under the Kyoto text. The Kyoto protocol raises questions about what activities can result in emissions credits, which carbon reservoirs will be counted, who will receive the credits, and how much credit will be available? …
Date: April 18, 1999
Creator: Marland, G. & Schlamadinger, B.
Object Type: Article
System: The UNT Digital Library
Characterization of Russian ballistic furnace shells (open access)

Characterization of Russian ballistic furnace shells

The authors received another batch of polystyrene ballistic furnace shells on December 4, 1998. Assigned the batch number of LSC012, it consisted of three cassettes containing 36 shells in each cassette. A group of 27 of the shells were selected for characterization that ranged in diameter from 1880 to 1780 {micro}m. There were two shells with a diameter above 1900 {micro}m, but they were too fragile and did not survive initial handling. For characterization, they examined the shells through a stereo microscope, measured diameter and sphericity on RACI, and weighed a subset of the 27 shells that did not have large particles or polymer shards adhered to the outside in order to calculate wall thickness. They then selected the cleanest and most spherical shells for Sphere Mapping. This batch of shells has about the same physical appearance as the one they documented August 26, 1998. There were some shells with polymer shards adhered to the outside, a few large vacuoles or large particle embedded in the polymer wall, and some with a scattering of small black particles on the outside. There were no swirls in the shell walls. As mentioned in the previous report, each shell is measured with the …
Date: February 18, 1999
Creator: Fearon, E
Object Type: Report
System: The UNT Digital Library
The Program for Climate Model Diagnosis and Intercomparison Diagnostic System: Implementing a New Strategy Beyond the Atmospheric Model Intercomparison Project (AMIP) (open access)

The Program for Climate Model Diagnosis and Intercomparison Diagnostic System: Implementing a New Strategy Beyond the Atmospheric Model Intercomparison Project (AMIP)

The Program for Climate Model Diagnosis and Intercomparison (PCMDI) was established in 1989 at the Lawrence Livermore National Laboratory (LLNL) with the principal mission to develop improved methods and tools for the diagnosis, validation and intercomparison of global climate models. The goal of the process is to eventually improve simulation of the regional climate effects of increasing greenhouse gases. In addition to comparing models, PCMDI continues to develop a modeling infrastructure by creating diagnostics that will be shared throughout the research community. PCMDI's early model intercomparison strategy was to solicit a few models that could be run for a specified period with prescribed sea-surface temperatures after being imported and adapted to the LLNL unclassified computer systems. Because of the enormous time required to prepare each model, the experiment was reversed and the modeling groups were asked to perform the controlled simulations themselves. In order to reach out to the entire atmospheric modeling community, the Working Group for Numerical Experimentation (WGNE) became the parent organization and the project was named the Atmospheric Model Intercomparison Project (AMIP). Eventually, more than thirty atmospheric modeling groups joined the effort to compare their model output (Gates et al. 1999). The general results showed that the …
Date: October 18, 1999
Creator: Potter, G.L.
Object Type: Article
System: The UNT Digital Library
Enhanced Design Alternative IV (open access)

Enhanced Design Alternative IV

This report evaluates Enhanced Design Alternative (EDA) IV as part of the second phase of the License Application Design Selection (LADS) effort. The EDA IV concept was compared to the VA reference design using criteria from the ''Design Input Request for LADS Phase II EDA Evaluations'' (CRWMS M&O 1999b) and (CRWMS M&O 1999f). Briefly, the EDA IV concept arranges the waste packages close together in an emplacement configuration known as ''line load''. Continuous pre-closure ventilation keeps the waste packages from exceeding the 350 C cladding and 200 C (4.3.13) drift wall temperature limits. This EDA concept keeps relatively high, uniform emplacement drift temperatures (post-closure) to drive water away from the repository and thus dry out the pillars between emplacement drifts. The waste package is shielded to permit human access to emplacement drifts and includes an integral filler inside the package to reduce the amount of water that can contact the waste form. Closure of the repository is desired 50 years after first waste is emplaced. Both backfill and a drip shields will be emplaced at closure to improve post-closure performance.
Date: May 18, 1999
Creator: Kramer, N. E.
Object Type: Report
System: The UNT Digital Library
Core-Level Satellites and Outer Core-Level Multiplet Splitting in Mn Model Compounds (open access)

Core-Level Satellites and Outer Core-Level Multiplet Splitting in Mn Model Compounds

We report a systematic study of the Mn 2p, 3s and 3p core-level photoemission and satellite structures for Mn model compounds. Charge-transfer from the ligand state to the 3d metal state is observed and is distinguished by prominent shake-up satellites. We also observe that the Mn 3s multiplet splitting becomes smaller as the Mn oxidation state increases, and that 3s-3d electron correlation reduces the branching ratio of the 7S:5S states in the Mn 3s spectra. In addition, as the ligand electronegativity decreases, the spin state purity is lost in the 3s spectra as evidenced by peak broadening. Our results are best understood in terms of the configuration-interaction (CI) model including intrashell electron correlation, charge-transfer and final-state screening.
Date: October 18, 1999
Creator: Nelson, A. J.; Reynolds, J. G. & Roos, J. W.
Object Type: Article
System: The UNT Digital Library
COMMERCIAL SNF ACCIDENT RELEASE FRACTIONS (open access)

COMMERCIAL SNF ACCIDENT RELEASE FRACTIONS

The purpose of this design analysis is to specify and document the total and respirable fractions for radioactive materials that are released from an accident event at the Monitored Geologic Repository (MGR) involving commercial spent nuclear fuel (CSNF) in a dry environment. The total and respirable release fractions will be used to support the preclosure licensing basis for the MGR. The total release fraction is defined as the fraction of total CSNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. The radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses. This subset of the total release fraction is referred to as …
Date: October 18, 1999
Creator: Bader, S.O.
Object Type: Report
System: The UNT Digital Library
SuperShuttle CNG Fleet Start-Up Experience (open access)

SuperShuttle CNG Fleet Start-Up Experience

The Gas Research Institute (GRI) and the U.S. Department of Energy (DOE), along with several industry partners, are collaborating with SuperShuttle of Denver, Colorado, to evaluate natural gas vans added to the SuperShuttle fleet in 1999. Brand new (1999 model year) dedicated and bi-fuel compressed natural gas (CNG) vans manufactured by Ford Motor Company will be operated side-by-side with several similar gasoline vehicles in normal revenue service. Once the study is complete, DOE's National Renewable Energy Laboratory will analyze and compile the results for release.
Date: May 18, 1999
Creator: Eudy, L.
Object Type: Book
System: The UNT Digital Library
Heating Distributions in the Target of the Spallation Neutron Source (open access)

Heating Distributions in the Target of the Spallation Neutron Source

Detailed calculation of the heat distributions in the structural parts of the target (Hg) and the target itself were made with realistic proton profiles. Preliminary current profiles of the protons coming from the accumulator ring, calculated and parameterized by the Brookhaven National Laboratory (BNL), were used as input to the Monte Carlo code LAHET. Due to limitations of the present version of the LAHET code, the real source was approximated with a nest of elliptical rings (all with the same eccentricity). The BNL's source was then fitted according to this elliptical description considering two constraints: (1) to preserve the areas of the contours of equal intensity of the real proton current density, and (2) to keep the ellipses with the same shape. In this way the best elliptical shape to describe the source was found. Because of the gaussian nature of the real current distribution, the elliptical fit is also gaussian in the elliptical coordinate.
Date: November 18, 1999
Creator: Charlton, L.A. & Difilippo, F.C.
Object Type: Article
System: The UNT Digital Library
Position Sensitive Scintillation Neutron Detectors Using a Crossed-Fiber Optic Readout Array (open access)

Position Sensitive Scintillation Neutron Detectors Using a Crossed-Fiber Optic Readout Array

The Spallation Neutron Source (SNS) under construction at the Oak Ridge National Laboratory will be the most important new neutron scattering facility in the United States. Neutron scattering instruments for the SNS will require large area detectors with fast response (< 1 microsecond), high efficiency over a wide range of neutron energies (0.1 to 10 eV), and low gamma ray sensitivity. We are currently developing area neutron detectors based on a combination of 6 LiF/ZnS scintillator screens coupled to a wavelength-shifting fiber optic readout array. A 25 x 25-cm prototype detector is currently under development. Initial tests at the High Flux Isotope Reactor have demonstrated good imaging properties coupled with very low gamma ray sensitivity. In addition, we have developed a multi-layer scintillator/fiber detector to replace existing He-3 gas detector tubes for higher speed operation. This detector has demonstrated a neutron detection efficiency of over 75% at a neutron energy of 0.056 eV or about twice thermal. The response time of this detector is approximately 1 microsecond. Details of the design and test results of both detectors will be presented.
Date: July 18, 1999
Creator: Holcomb, David E.; Hutchinson, Donald P.; Ramsey, James A. & Richards, Roger K.
Object Type: Article
System: The UNT Digital Library
Effects of Hardness on Pintle Rod Performance in the Universal and Retained Gas Samplers (open access)

Effects of Hardness on Pintle Rod Performance in the Universal and Retained Gas Samplers

Interaction between hardness of the pintle rods and the retainer rings used in the core samplers is investigated. It is found that ordinary Rockwell C measurements are not sufficient and superficial hardness instruments are recommended to verify hardness since in-production hardness of pintle rods is found to vary widely and probably leads to some premature release of pistons in samplers.
Date: November 18, 1999
Creator: Boger, R. M.
Object Type: Report
System: The UNT Digital Library
ROSE: The Design of a General Tool for the Independent Optimization of Object-Oriented Frameworks (open access)

ROSE: The Design of a General Tool for the Independent Optimization of Object-Oriented Frameworks

ROSE represents a programmable preprocessor for the highly aggressive optimization of C++ object-oriented frameworks. A fundamental feature of ROSE is that it preserves the semantics, the implicit meaning, of the object-oriented framework's abstractions throughout the optimization process, permitting the framework's abstractions to be recognized and optimizations to capitalize upon the added value of the framework's true meaning. In contrast, a C++ compiler only sees the semantics of the C++ language and thus is severely limited in what optimizations it can introduce. The use of the semantics of the framework's abstractions avoids program analysis that would be incapable of recapturing the framework's full semantics from those of the C++ language implementation of the application or framework. Just as no level of program analysis within the C++ compiler would not be expected to recognize the use of adaptive mesh refinement and introduce optimizations based upon such information. Since ROSE is programmable, additional specialized program analysis is possible which then compliments the semantics of the framework's abstractions. Enabling an optimization mechanism to use the high level semantics of the framework's abstractions together with a programmable level of program analysis (e.g. dependence analysis), at the level of the framework's abstractions, allows for the design …
Date: May 18, 1999
Creator: Davis, K.; Philip, B. & Quinlan, D.
Object Type: Article
System: The UNT Digital Library
Set point calculations for RAPID project (open access)

Set point calculations for RAPID project

The Respond and Pump in Days (RAPID) project was initiated to pump part of the contents of tank 241-SY-101 into tank 241-SY-102. This document establishes the basis for all set points and ranges used in the RAPID project.
Date: October 18, 1999
Creator: Hickman, G. L.
Object Type: Report
System: The UNT Digital Library
Controlling the Expansion of Laser-Fusion Plasma to Minimize Impact Damage (open access)

Controlling the Expansion of Laser-Fusion Plasma to Minimize Impact Damage

I propose to analytically model the rapid, nonequilibrium expansion of laser-fusion plasma from an initial diameter of 1 mm to a final diameter of 10 m. The aim is to devise a counterforce that minimizes the impact damage on optics by laser-plasma debris. This flow model is the basis of an idea for a dynamic target that efficiently converts laser energy to x-rays while minimizing the total mass propelled as debris. Also, the flow model is the basis of an idea to magnetically deflect material away from the optic ports in the vacuum chamber wall. The model combines results for supersonic one-dimensional gas flow of cylindrical-hemispherical symmetry, with a transition from thermal to nonequilibrium (''frozen'') plasma flow, which is set differently along each characteristic line (the ''Bray criterion'' as a Riemann invariant). The model shows how density, pressure, velocity, ionization fraction, electron temperature, and electrical conductivity vary over space and time, given an impulsively-heated source mass. The model is analytical, and examples are calculated on a desktop computer. This ease-of-use makes it possible to iterate quickly when refining ideas, such as a dynamic metal-vapor target that propels minimal debris, and a magnetohydrodynamic generator as a brake on the flow speed …
Date: March 18, 1999
Creator: Garcia, M.
Object Type: Report
System: The UNT Digital Library