Ultra-intense, short pulse laser-plasma interactions with applications to the fast ignitor (open access)

Ultra-intense, short pulse laser-plasma interactions with applications to the fast ignitor

Due to the advent of chirped pulse amplification (CPA) as an efficient means of creating ultra-high intensity laser light (I > 5{times}10{sup 17} W/cm{sup 2}) in pulses less than a few picoseconds, new ideas for achieving ignition and gain in DT targets with less than 1 megajoule of input energy are currently being pursued. Two types of powerful lasers are employed in this scheme: (1) channeling beams and (2) ignition beams. The current state of laser-plasma interactions relating to this fusion scheme will be discussed. In particular, plasma physics issues in the ultra-intense regime are crucial to the success of this scheme. We compare simulation and experimental results in this highly nonlinear regime.
Date: April 1, 1995
Creator: Wilks, S. C.; Kruer, W. L.; Young, P. E.; Hammer, J. & Tabak, M.
Object Type: Article
System: The UNT Digital Library
Technical evaluation report for the demonstration of radio frequency soil decontamination at Site S-1 (open access)

Technical evaluation report for the demonstration of radio frequency soil decontamination at Site S-1

The Air Force`s Armstrong Laboratory at Tyndall Air Force Base, Florida, has supported the research and development of Radio Frequency Soil Decontamination. Radio frequency soil decontamination is essentially a heat-assisted soil vapor extraction process. Site S-1 at Kelly Air Force Base, San Antonio, Texas, was selected for the demonstration of two patented techniques. The site is a former sump that collected spills and surface run-off from a waste petroleum, oils, and lubricants and solvent storage and transfer area. In 1993, a technique developed by the IIT Research Institute using an array of electrodes placed in the soil was demonstrated. In 1994, a technique developed by KAI Technologies, Inc. using a single applicator placed in a vertical borehole was demonstrated. Approximately 120 tons of soil were heated during each demonstration to a temperature of about 150 degrees Celsius.
Date: April 1, 1995
Creator: Lyon, Chesley R.; Blanchard, Clifton F. & Whitt, Laura H.
Object Type: Report
System: The UNT Digital Library
Transformations in organic sulfur speciation during maturation of Monterey shale: Constraints from laboratory experiments (open access)

Transformations in organic sulfur speciation during maturation of Monterey shale: Constraints from laboratory experiments

A series of hydrous pyrolysis experiments were conducted at temperatures ranging from 125 to 360C at 350 bars pressure to examine variations in sulfur speciation during thermal maturation of Monterey shale. The total sediment, kerogen and bitumen from each experiment in addition to unheated representatives were analyzed via x-ray absorption spectroscopy, pyrolysis-gas chromatography, {sup 30}NMR spectrometry, elemental analysis, thin-layer chromatography and reflected light microscopy. Based on these measurements, it was possible to recognize three distinct temperature regimes, within which the type and amount of sulfur in the analyzed fractions underwent transformations: (1) between 150 and 225C significant proportion of kerogen-bound sulfur is lost probably due to the collapse of polysulfide bridges; (2) between 225 and 275C, cleavage of -S-S- and -S-C- linkages within the kerogen is believed to occur, resulting in substantial production of polar sulfur-rich bitumen; (3) above 275C total bitumen yields as well as the proportion of bitumen sulfur decrease, while C-C bond scission leads to increased yields of saturated and aromatic hydrocarbons. The results from this study clearly and quantitatively establish a link between organically-bound sulfur, and more specifically, organic polysulfides, and the low-temperature evolution of soluble petroleum-like products (bitumen) from sulfur-rich source rocks.
Date: April 1995
Creator: Nelson, B. C.; Eglinton, T. I.; Seewald, J. S.; Vairavamurthy, M. A. & Miknis, F. P.
Object Type: Report
System: The UNT Digital Library
Test plan for the data acquisition and management system for monitoring the fuel oil spill at the Sandia National Laboratories installation in Livermore, California (open access)

Test plan for the data acquisition and management system for monitoring the fuel oil spill at the Sandia National Laboratories installation in Livermore, California

This report describes the formal test plan that will be used for the data acquisition and management system developed to monitor a bioremediation study by Argonne National Laboratory in association with Sandia National Laboratories. The data acquisition and management system will record the site data during the bioremediation and assist experts in site analysis. The three major subsystems of this system are described in detail in this report. In addition, this report documents the component- and system-level test procedures that will be implemented at each phase of the project. Results of these test procedures are documented in this report.
Date: April 1, 1995
Creator: Widing, M.A.; Dominiak, D.M.; Leser, C.C.; Peerenboom, J.P. & Manning, J.F.
Object Type: Report
System: The UNT Digital Library
Beam lifetime and beam brightness in ALS (open access)

Beam lifetime and beam brightness in ALS

Beam lifetime in ALS is dominated by the Touschek scattering. Measurements of lifetime in single-bunch mode with estimates of bunch dimensions obtained from undulator radiation data are consistent with expectations (t=1.8 hours at 1.25 mA per bunch). However, the lifetime is significantly longer in multi-bunch mode (t=ll hours at 400 mA per 320 bunches). This discrepancy has been traced to an increase in the momentum spread and bunch length in the beam caused by longitudinal coupled-bunch motions driven by higher-order modes in the rf cavities. The increased momentum spread leads to a significant degradation in the undulator spectral performance. Feedback stabilization of the coupled-bunch motion improves the spectral characteristics of the undulator beam at the expense of beam lifetime. We observe an increase of {approximately}200% in beam lifetime by operating at the betatron coupling resonance.
Date: April 1, 1995
Creator: Kim, C.; Jackson, A. & Warwick, A.
Object Type: Article
System: The UNT Digital Library
Development of radiation detectors based on hydrogenated amorphous silicon and its alloys (open access)

Development of radiation detectors based on hydrogenated amorphous silicon and its alloys

Hydrogenated amorphous silicon and related materials have been applied to radiation detectors, utilizing their good radiation resistance and the feasibility of making deposits over a large area at low cost. Effects of deposition parameters on various material properties of a-Si:H have been studied to produce a material satisfying the requirements for specific detection application. Thick(-{approximately}50 {mu}m), device quality a-Si:H p-i-n diodes for direct detection of minimum ionizing particles have been prepared with low internal stress by a combination of low temperature growth, He-dilution of silane, and post annealing. The structure of the new film contained voids and tiny crystalline inclusions and was different from the one observed in conventional a-Si:H. Deposition on patterned substrates was attempted as an alternative to controlling deposition parameters to minimize substrate bending and delamination of thick a-Si:H films. Growth on an inversed-pyramid pattern reduced the substrate bending by a factor of 3{approximately}4 for the same thickness film. Thin (0.1 {approximately} 0.2 {mu}m) films of a-Si:H and a-SiC:H have been applied to microstrip gas chambers to control gain instabilities due to charges on the substrate. Light sensitivity of the a-Si:H sheet resistance was minimized and the surface resistivity was successfully` controlled in the range of 10{sup …
Date: April 1, 1995
Creator: Hong, Wan-Shick
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Theory and numerical application of subsurface flow and transport for transient freezing conditions (open access)

Theory and numerical application of subsurface flow and transport for transient freezing conditions

Protective barriers are being investigated for the containment of radioactive waste within subsurface environments. Predicting the effectiveness of cryogenic barriers and near-surface barriers in temperate or arctic climates requires capabilities for numerically modeling subsurface flow and transport for freezing soil conditions. A predictive numerical model is developed herein to simulate the flow and transport of radioactive solutes for three-phase (water-ice-air) systems under freezing conditions. This physically based model simulates the simultaneous flow of water, air, heat, and radioactive solutes through variably saturated and variably frozen geologic media. Expressions for ice (frozen water) and liquid water saturations as functions of temperature, interfacial pressure differences, and osmotic potential are developed from nonhysteretic versions of the Brooks and Corey and van Genuchten functions for soil moisture retention. Aqueous relative permeability functions for variably saturated and variably frozen geologic media are developed from the Mualem and Burdine theories for predicting relative permeability of unsaturated soil. Soil deformations, caused by freezing and melting transitions, are neglected. Algorithms developed for predicting ice and liquid water saturations and aqueous-phase permeabilities were incorporated into the finite-difference based numerical simulator STOMP (Subsurface Transport Over Multiple Phases). Application of the theory is demonstrated by the solution of heat and mass …
Date: April 1, 1995
Creator: White, M. D.
Object Type: Report
System: The UNT Digital Library
Proceedings of the natural gas RD&D contractors review meeting, Volume I (open access)

Proceedings of the natural gas RD&D contractors review meeting, Volume I

This report contains papers which were presented at the natural gas contractors review meeting held on April 4-6, 1995. Topics were concerned with resource and reserves, low permeability reservoir characterization, natural fracture detection, drilling, completion, and stimulation, and natural gas upgrading. Individual papers were processed separately for the United States Department of Energy databases.
Date: April 1, 1995
Creator: Malone, R.D.
Object Type: Article
System: The UNT Digital Library
Evaporative oxidation treatability test report (open access)

Evaporative oxidation treatability test report

In 1992, Congress passed the Federal Facilities Compliance Act that requires the U.S. Department of Energy (DOE) to treat and dispose of its mixed waste in accordance with the Resource Conservation and Recovery Act (RCRA) land disposal restrictions (LDRs). In response to the need for mixed-waste treatment capacity where available off-site commercial treatment facilities do not exist or cannot be used, the DOE Albuquerque Operations Office (DOE-AL) organized a Treatment Selection Team to match mixed wastes with treatment options and develop a strategy for treatment of its mixed wastes. DOE-AL manages operations at nine sites with mixed-waste inventories. The Treatment Selection Team determined a need to develop mobile treatment capacity to treat wastes at the sites where the wastes are generated. Treatment processes used for mixed waste not only must address the hazardous component (i.e., meet LDRs) but also must contain the radioactive component in a form that allows final disposal while protecting workers, the public, and the environment. On the basis of recommendations of the Treatment Selection Team, DOE-AL assigned projects to the sites to bring mixed-waste treatment capacity on-line. The three technologies assigned to the DOE Grand Junction Projects Office (GJPO) are evaporative oxidation, thermal desorption, and treated …
Date: April 1, 1995
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Heavy ion fusion 2 MV injector (open access)

Heavy ion fusion 2 MV injector

A heavy-ion-fusion driver-scale injector has been constructed and operated at Lawrence Berkeley Laboratory. The injector has produced 2.3 MV and 950 mA of K{sup +}, 15% above original design goals in energy and current. Normalized edge emittance of less than 1 {pi} mm-mr was measured over a broad range of parameters. The head-to-tail energy flatness is less than {+-} 0.2% over the 1 {micro}s pulse.
Date: April 1, 1995
Creator: Yu, S.; Eylon, S. & Henestroza, E.
Object Type: Article
System: The UNT Digital Library
Declustering databases on heterogeneous disk systems (open access)

Declustering databases on heterogeneous disk systems

Declustering is a well known strategy to achieve maximum I/O parallelism in multi-disk systems. Many declustering methods have been proposed for symmetrical disk systems, i.e., multi-disk systems in which all disks have the same speed and capacity. This work deals with the problem of adapting such declustering methods to work in heterogeneous environments. In such environments these are many types of disks and servers with a large range of speeds and capacities. We deal first with the case of perfectly declustered queries, i.e., queries which retrieve a fixed proportion of the answer from each disk. We show that the fraction of the dataset which must be allocated to each disk is affected by both the relative speed and capacity of the disk. Furthermore, the hierarchical structure of most distributed systems, where groups of disks are placed in servers, imposes further complications due to variations . in server and network bandwidths which may affect the actual achievable transfer rates. We propose an algorithm which determines the fraction of the dataset which must be loaded on each disk. The algorithm may be tailored to find disk loading for minimal response time for a given database size, or to compute a system profile …
Date: April 1, 1995
Creator: Chen, Ling T.; Rotem, D. & Seshadri, S.
Object Type: Article
System: The UNT Digital Library
Photofragment translational spectroscopy of three body dissociations and free radicals (open access)

Photofragment translational spectroscopy of three body dissociations and free radicals

This dissertation describes several three-body dissociations and the photodissociation of methyl radicals studied using photofragment translational spectroscopy. The first chapter provides an introduction to three body dissociation, examines current experimental methodology, and includes a discussion on the treatment of photofragment translational spectroscopy data arising from three-body fragmentation. The ultraviolet photodissociation of azomethane into two methyl radicals and nitrogen is discussed in chapter 2. Chapter 3 describes the photodissociation of acetone at 248 nm and 193 nm. At 248 nm the translational energy release from the initial C-C bond cleavage matches the exit barrier height and a comparison with results at 266 nm suggests that <E{sub T}> is invariant to the available energy. A fraction of the nascent CH{sub 3}CO radicals spontaneously dissociate following rotational averaging. The <E{sub T}> for the second C-C bond cleavage also matches the exit barrier height. At 193 nm the experimental data can be successfully fit assuming that the dynamics are analogous to those at 248 nm. A simplified model of energy partitioning which adequately describes the experimental results is discussed. Experiments on acetyl halides provide additional evidence to support the proposed acetone dissociation mechanism. A value of 17.0{+-}1.0 kcal/mole for the barrier height, CH{sub 3}CO …
Date: April 1, 1995
Creator: North, S.W.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Methods of constructing a 3D geological model from scatter data (open access)

Methods of constructing a 3D geological model from scatter data

Most geoscience applications, such as assessment of an oil reservoir or hazardous waste site, require geological characterization of the site. Geological characterization involves analysis of spatial distributions of lithology, porosity, etc. Because of the complexity of the spatial relationships, the authors find that a 3-D model of geology is better suited for integration of many different types of data and provides a better representation of a site than a 2-D one. A 3-D model of geology is constructed from sample data obtained from field measurements, which are usually scattered. To create a volume model from scattered data, interpolation between points is required. The interpolation can be computed using one of several computational algorithms. Alternatively, a manual method may be employed, in which an interactive graphics device is used to input by hand the information that lies between the data points. For example, a mouse can be used to draw lines connecting data points with equal values. The combination of these two methods presents yet another approach. In this study, the authors will compare selected methods of 3-D geological modeling, They used a flow-based, modular visualization environment (AVS) to construct the geological models computationally. Within this system, they used three modules, …
Date: April 1, 1995
Creator: Horsman, J. & Bethel, W.
Object Type: Report
System: The UNT Digital Library
The Brookhaven National Laboratory filter pack system for collection and determination of air pollutants (open access)

The Brookhaven National Laboratory filter pack system for collection and determination of air pollutants

A filter pack system for sampling trace constituents in the atmosphere from aircraft and ground-based measurement platforms has been developed. The system simultaneously and quantitatively collects atmospheric aerosol, nitric acid, and sulfur dioxide using three sequential filter stages. The quartz aerosol filter is routinely analyzed for sulfate, nitrate, ammonium, and hydrogen ions, and specifically for sulfuric acid. The sodium chloride filter is analyzed for nitrate ion (from collected nitric acid), and the carbonate-glycerine filter for sulfate ion (from collected sulfur dioxide). Details of the procedures used for filter preparation, sampling, extraction and analysis are given.
Date: April 1, 1995
Creator: Leahy, D. F.; Klotz, P. J.; Springston, S. R. & Daum, P. H.
Object Type: Report
System: The UNT Digital Library
Analysis and design modifications for upgrade of storage ring bump pulse system driving the injection bump magnets at the ALS (open access)

Analysis and design modifications for upgrade of storage ring bump pulse system driving the injection bump magnets at the ALS

A fast (4.0 ms half period) resonant discharge pulse system, using SCRs, was designed and constructed to drive the injection bump magnet system at the Advanced Light Source (ALS). The commissioning process revealed a high frequency resonance (T = 800 NS) superimposed on the driver discharge wave form. In addition, the peak amplitude of the magnet load recovery current exceeded design specifications. A SPICE analysis confirmed the suspected mechanisms for the parasitic ringing and the excessive load current {open_quotes}undershoot{close_quotes}. This paper will address the subsequent analysis, measurements, and modifications carried out during the maintenance shutdown in June 1993.
Date: April 1, 1995
Creator: Stover, G. D.
Object Type: Article
System: The UNT Digital Library
Addendum to the post-closure permit application for the Bear Creek hydrogeologic regime at the Y-12 plant: Walk-in pits (open access)

Addendum to the post-closure permit application for the Bear Creek hydrogeologic regime at the Y-12 plant: Walk-in pits

In June 1987, the Resource Conservation and Recovery Act (RCRA) Closure/Post-Closure Plan for the Bear Creek Burial Grounds (BCBG) located at the Y-12 Plant on the Oak Ridge Reservation in Oak Ridge, Tennessee was submitted to the Tennessee Department of Environment and Conservation (TDEC) for review and approval.The Closure Plan has been modified and revised several times. This document is an addendum to the Post-Closure Permit Application submitted to TDEC in June, 1994. This addendum contains information on the Walk-In Pits of the BCBG which is meant to supplement the information provided in the Post-Closure Permit Application submitted for the BCBG. This document is not intended to be a stand-alone document.
Date: April 1, 1995
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Electron Acceleration in Relativistic Plasma Waves Generated by a Single Frequency Short-Pulse Laser (open access)

Electron Acceleration in Relativistic Plasma Waves Generated by a Single Frequency Short-Pulse Laser

Experimental evidence for the acceleration of electrons in a relativistic plasma wave generated by Raman forward scattering (SRS-F) of a single-frequency short pulse laser are presented. A 1.053 {mu}m, 600 fsec, 5 TW laser was focused into a gas jet with a peak intensity of 8{times}10{sup 17} W/cm{sup 2}. At a plasma density of 2{times}10{sup 19} cm{sup {minus}3}, 2 MeV electrons were detected and their appearance was correlated with the anti-Stokes laser sideband generated by SRS-F. The results are in good agreement with 2-D PIC simulations. The use of short pulse lasers for making ultra-high gradient accelerators is explored.
Date: April 27, 1995
Creator: Coverdale, C. A.; Darrow, C. B.; Decker, C. D.; Mori, W. B.; Tzeng, K. C.; Clayton, C. E. et al.
Object Type: Article
System: The UNT Digital Library
Results of performance tests on chemical and radiation measurement systems for use at a dig-face (open access)

Results of performance tests on chemical and radiation measurement systems for use at a dig-face

Chemical and radiation measurement systems are being developed for use at a dig-face to provide sensing capability during the excavation of previously buried waste. it is believed that on-line dig-face characterization will reduce environmental, health, and safety risks during the cleanup of buried waste sites as well as improve the efficiency of the cleanup process. This report describes progress in the development of three measurement systems: (a) a {gamma}/neutron monitor that scans the dig-face for high levels of radiation prior to excavation, (b) a Ge spectrometer that identifies specific radionuclides located with the {gamma}/neutron monitor, and (c) a prompt {gamma} neutron activation analysis (PGNAA) system that measures the presence of chlorine and chlorinated compounds often associated with hazardous waste. The Ge spectrometer and PGNAA system also will provide off-line but on-site capability of radionuclide and elemental identification of excavated waste prior to handling, treatment, transportation, or disposal.
Date: April 1, 1995
Creator: Gehrke, R. J.; Lawrence, R. S. & Pawelko, R. J.
Object Type: Report
System: The UNT Digital Library
Reduction of nonlinear resonance excitation from insertion devices in the ALS (open access)

Reduction of nonlinear resonance excitation from insertion devices in the ALS

Theoretical studies of Lawrence Berkeley Laboratory's Advanced Light Source (ALS) storage ring predict strong field insertion devices will break the rings symmetry, increasing resonance excitation that may reduce the dynamic aperture and thus the beam lifetime. The authors have embarked on an experimental program to study the strength of nonlinear resonance excitation in the ALS when insertion devices are present. They observe an enhancement in the resonance excitation of a third-order resonance when the gap of the insertion device is narrowed. They also find that it is possible to suppress this resonance by detuning two quadruples on either side of the insertion device. The results of this study are presented in this paper.
Date: April 1, 1995
Creator: Robin, D.; Krebs, G.; Portmann, G.; Zholents, A. & Decking, W.
Object Type: Article
System: The UNT Digital Library
Optimization of microwave heating in an existing cubicle cavity by incorporating additional wave guide and control components (open access)

Optimization of microwave heating in an existing cubicle cavity by incorporating additional wave guide and control components

The use of microwave energy to thermally treat Low Level (LLW), Transuranic (TRU), and mixed waste has been under development at the Rocky Flats Environmental Technology Site (Site) since 1986. During that time, the technology has progressed from bench-scale tests, through pilot-scale tests, and finally to a full-scale demonstration unit. Experimental operations have been conducted on a variety of non-radioactive surrogates and actual radioactive waste forms. Through these studies and development efforts, the Microwave Vitrification Engineering Team (MVET) at Rocky Flats has successfully proven the application of microwave energy for waste treatment operations. In the microwave solidification process, microwave energy is used to heat a mixture of waste and glass frit to produce a vitrified product that meets all the current acceptance criteria at the final disposal sites. All of the development to date has utilized a multi-mode microwave system to provide the energy to treat the materials. Currently, evaluations are underway on modifications to the full-scale demonstration system that provide a single-mode operation as a possible method to optimize the system. This poster presentation describes the modifications made to allow the single-mode operation.
Date: April 1, 1995
Creator: Erle, R.R.; Eschen, V.G. & Sprenger, G.S.
Object Type: Report
System: The UNT Digital Library
Double pulse experiment with a velvet cathode on the ATA injector (open access)

Double pulse experiment with a velvet cathode on the ATA injector

Double pulse transport experiments were conducted on the front end of the ATA accelerator to obtain data on the capability of a velvet cloth cathode to produce two successive pulses. Pulses of approximately 3 kA were extracted from the cathode with interpulse spacings varying from 150 ns to 2.8 {micro}s using an anode-cathode voltage of about 1 MV. Analysis of the current and voltage waveform data from the injector indicate that the effects of cathode plasma on the second pulse of a two-pulse burst is minimal.
Date: April 24, 1995
Creator: Westenskow, G.; Caporaso, G.; Chen, Y.; Houck, T. & Sampayan, S.
Object Type: Report
System: The UNT Digital Library
Calculations of protective action distance for toxic chemical spills using nomographs (open access)

Calculations of protective action distance for toxic chemical spills using nomographs

This document was produced for emergency use following a spill of liquid gas or finely divided solid (<100 micron) toxic chemicals. The information on the next few pages was kept deliberately terse and is limited to data and graphic aids needed for calculation of plume distance (protective action distance). All supporting material is provided as Appendices.
Date: April 1, 1995
Creator: Lee, L.G.; Vail, J.A. & Gibeault, G.L.
Object Type: Report
System: The UNT Digital Library
Hydrothermally treated coals for pulverized coal injection. [Quarterly] technical progress report, January--March 1995 (open access)

Hydrothermally treated coals for pulverized coal injection. [Quarterly] technical progress report, January--March 1995

This project is investigating the suitability of hydrothermally dried low-rank coals for pulverized fuel injection into blast furnaces in order to reduce coke consumption. Coal samples from the Beluga coal field and the Usibelli Coal Mine, Alaska, are being used for the study. Crushed coal samples were hydrothermally treated at three temperatures, 275, 300 and 325{degrees}C, for residence times ranging from 10 to 120 minutes. Products are being characterized to determine their suitability for pulverized coal injection. Characterization includes proximate and ultimate analyses, vitrinite reflectance and TGA reactivity. A literature survey is being conducted.
Date: April 1, 1995
Creator: Walsh, D.E.; Rao, P.D.; Ogunsola, O. & Lin, H.K.
Object Type: Report
System: The UNT Digital Library
In situ air stripping using horizontal wells. Innovative technology summary report (open access)

In situ air stripping using horizontal wells. Innovative technology summary report

In-situ air stripping employs horizontal wells to inject or sparge air into the ground water and vacuum extract VOC`S from vadose zone soils. The horizontal wells provide better access to the subsurface contamination, and the air sparging eliminates the need for surface ground water treatment systems and treats the subsurface in-situ. A full-scale demonstration was conducted at the Savannah River Plant in an area polluted with trichloroethylene and tetrachloroethylene. Results are described.
Date: April 1, 1995
Creator: unknown
Object Type: Report
System: The UNT Digital Library