2w Laser Propagation and Raman Backscatter in Underdense Gas Bag Plasmas (open access)

2w Laser Propagation and Raman Backscatter in Underdense Gas Bag Plasmas

Recent 2{omega} gasbag experiments on the Helen laser studied single-beam propagation and backscatter as a function of gas density. We present a comprehensive analysis of these experiments using simulations in HYDRA. Post-processed results agree well with experimental fast x-ray images (FXI) showing stable laser propagation across the bag. The measured total stimulated Raman backscatter (SRS) increases with initial gas density up to n{sub e} {approx} 0.08 n{sub c}, then decreases. Near-backscatter images (NBI) show that the decrease in total SRS with increasing density is not due to scatter outside of the collection optics. SRS gain spectra calculated from the HYDRA results agree well with experimental streak spectra. The tilt and spread in wavelength of the spectra appear to be explained by gasbag hydrodynamics only, with no need to invoke filamentation. Axial density gradients and laser pump absorption may combine to detune and limit SRS gain at high density.
Date: September 5, 2003
Creator: Meezan, N.; Divol, L.; Suter, L.; Miller, M.; Stevenson, R. M.; Slark, G. et al.
Object Type: Article
System: The UNT Digital Library
Actinic Mask Inspection at the ALS Initial Design Review (open access)

Actinic Mask Inspection at the ALS Initial Design Review

This report is the first milestone report for the actinic mask blank inspection project conducted at the VNL, which forms sub-section 3 of the Q1 2003 mask blank technology transfer program at the VNL. Specifically this report addresses deliverable 3.1.1--design review and preliminary tool design. The goal of this project is to design an actinic mask inspection tool capable of operating in two modes: high-speed scanning for the detection of multilayer defects (inspection mode), and a high-resolution aerial image mode in which the image emulates the imaging illumination conditions of a stepper system (aerial image or AIM mode). The purpose and objective of these two modes is as follows: (1) Defect inspection mode--This imaging mode is designed to scan large areas of the mask for defects EUV multilayer coatings. The goal is to detect the presence of multilayer defects on a mask blank and to store the co-ordinates for subsequent review in AIM mode, thus it is not essential that the illumination and imaging conditions match that of a production stepper. Potential uses for this imaging mode include: (a) Correlating the results obtained using actinic inspection with results obtained using other non-EUV defect inspection systems to verify that the non-EUV …
Date: March 5, 2003
Creator: Barty, A.; Chapman, H.; Sweeney, D.; Levesque, R.; Bokor, J.; Gullikson, E. et al.
Object Type: Report
System: The UNT Digital Library
Addressing Problems with Scene-Based Wave Front Sensing (open access)

Addressing Problems with Scene-Based Wave Front Sensing

Scene-Based Wave Front Sensing uses the correlation between successive subimages to determine phase aberrations which blur digital images. Adaptive Optics technology uses deformable mirrors to correct for these phase aberrations and make the images clearer. The correlation between temporal subimages gives tip-tilt information. If these images do not have identical image content, tip-tilt estimations may be incorrect. Motion detection is necessary to help avoid errors initiated by dynamic subimage content. In this document, I will discuss why edge detection fails as a motion detection method on low resolution images and how thresholding the normalized variance of individual pixels is successful for motion detection.
Date: August 5, 2003
Creator: Chan, C
Object Type: Report
System: The UNT Digital Library
All Fiber Technology for High-Energy Petawatt Front End Laser Systems (open access)

All Fiber Technology for High-Energy Petawatt Front End Laser Systems

We are developing an all fiber front end for the next generation high-energy petawatt (HEPW) laser at Lawrence Livermore National Laboratory (LLNL). The ultimate goal of the LLNL HEPW effort is to generate 5-kJ pulses capable of compression to 5ps at 1053nm, enabling advanced x-ray backlighters and possible demonstration of fast ignition. We discuss the front-end of the laser design from the fiber master oscillator, which generates the mode-locked 20nm bandwidth initial pulses through the 10mJ output of the large flattened mode (LFM) fiber amplifier. Development of an all fiber front end requires technological breakthroughs in the key areas of the master oscillator and fiber amplification. Chirped pulse amplification in optical fibers has been demonstrated to 1mJ. Further increase is limited by the onset of stimulated Raman scattering (SRS). We have recently demonstrated a new flattened mode fiber technology, which reduces peak power for a given energy and thus the onset of SRS. Controlled experiments with 1st generation fibers yielded 0.5mJ of energy while significantly increasing the point at which nonlinear optical effects degrade the amplified pulse. In this paper we will discuss our efforts to extend this work to greater than 20mJ using our large flattened mode fiber amplifier.
Date: September 5, 2003
Creator: Dawson, J W; Liao, Z M; Jovanovic, I; Wattellier, B; Beach, R; Payne, S A et al.
Object Type: Article
System: The UNT Digital Library
ALS user meeting features 10th anniversary celebration (open access)

ALS user meeting features 10th anniversary celebration

The Advanced Light Source (ALS) saw first light on October 5, 1993, not quite to the day but close to 10 years before the 2003 ALS Users Association meeting, held October 6-8. Fittingly, the proceedings included retrospectives from two of the key players in the early history of the ALS, David Attwood and Jay Marx, and a display of photographs chronicling its construction and commissioning. Science highlights, highlights from young researchers, and posters constituted the meat of the program on Monday and Tuesday morning, while workshops took over Tuesday afternoon and all day Wednesday.
Date: December 5, 2003
Creator: Robinson, Art
Object Type: Article
System: The UNT Digital Library
Aperture studies for the AP2 anti-proton Line at Fermilab (open access)

Aperture studies for the AP2 anti-proton Line at Fermilab

The AP2 beamline transports anti-protons from the production target to the Debuncher ring. For many years the observed aperture has been smaller than that estimated from linear, on-energy optics. We have investigated possible reasons for the aperture restriction and have identified several possible sources, including residual vertical dispersion from alignment errors and chromatic effects due to very large chromatic lattice functions. We discuss the possible sources, suggest some remedies, and propose specific studies, where needed, to evaluate suspected problems.
Date: December 5, 2003
Creator: Reichel, Ina; Zisman, Michael & Placidi, Massimo
Object Type: Report
System: The UNT Digital Library
Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf San Andres Reservoir. Annual Report: August 3, 2000--August 2, 2001 (open access)

Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf San Andres Reservoir. Annual Report: August 3, 2000--August 2, 2001

The OXY-operated Class 2 Project at West Welch is designed to demonstrate how the use of advanced technology can improve the economics of miscible CO{sub 2} injection projects in lower quality Shallow Shelf Carbonate reservoirs. The research and design phase (Budget Period 1) primarily involved advanced reservoir characterization. The current demonstration phase (Budget Period 2) is the implementation of the reservoir management plan for an optimum miscible CO{sub 2} flood design based on the reservoir characterization. Although Budget Period 1 for the Project officially ended 12/31/96, reservoir characterization and simulation work continued during the Budget Period 2. During the seventh annual reporting period (8/3/00-8/2/01) covered by this report, work continued on interpretation of the interwell seismic data to create porosity and permeability profiles which were distributed into the reservoir geostatistically. The initial interwell seismic CO{sub 2} monitor survey was conducted and the acquired data processed and interpretation started. Only limited well work and facility construction were conducted in the project area. The CO{sub 2} injection initiated in October 1997 was continued, although the operator had to modify the operating plan in response to low injection rates, well performance and changes in CO{sub 2} supply. CO{sub 2} injection was focused in …
Date: May 5, 2003
Creator: Beebe, Tom
Object Type: Report
System: The UNT Digital Library
Assessment of Physical Properties of Transuranic Waste in Hanford Single-Shell Tanks (open access)

Assessment of Physical Properties of Transuranic Waste in Hanford Single-Shell Tanks

CH2M HILL Hanford Group, Inc. (CH2M HILL) is in the process of identifying and developing supplemental process technologies to accelerate the tank waste cleanup mission. One technology targets disposal of Hanford transuranic (TRU) process wastes stored in single-shell tanks (SSTs). Ten Hanford SSTs are candidates for designation as contact-handled TRU waste type: the B-200 series tanks (241-B-201, -B-202, -B-203, and -B-204), the T-200 series tanks (241-T-201, -T-202, -T-203, and -T-204), and Tanks 241-T-110 and T-111. Current plans identify a process in which these wastes are retrieved from the tanks, either dry or with a recycled liquid stream to help mobilize the waste in the tank and through transfer lines and vessels, dewatered to remove excess liquid, and transferred to waste packages in a form suitable for disposal. CH2M HILL seeks to procure a process for dewatering, handling, and packaging the contact-handled TRU waste after it is retrieved. An understanding of waste physical properties is needed to support design of the SST TRU handling and packaging system and to produce suitable physical simulants to test such a process. Pacific Northwest National Laboratory (PNNL) has been tasked with developing these waste simulants. This report summarizes PNNL's assessment of available waste physical property …
Date: March 5, 2003
Creator: Rassat, Scot D.; Mahoney, Lenna A.; Wells, Beric E.; Mendoza, Donaldo P. & Caldwell, Dustin D.
Object Type: Report
System: The UNT Digital Library
Assessment of Unabated Facility Emission Potentials for Evaluating Airborne Radionuclide Monitoring Requirements at Pacific Northwest National Laboratory - 2003 (open access)

Assessment of Unabated Facility Emission Potentials for Evaluating Airborne Radionuclide Monitoring Requirements at Pacific Northwest National Laboratory - 2003

Assessments were performed to evaluate compliance with the airborne radionuclide emission monitoring requirements in the National Emission Standards for Hazardous Air Pollutants (NESHAP - U.S. Code of Federal Regulations, Title 40, Part 61, Subpart H) and Washington Administrative Code (WAC) 246-247: Radiation Protection - Air Emissions. In these assessments, potential unabated offsite doses were evaluated for emission locations at facilities owned by the U.S. Department of Energy and operated by Pacific Northwest National Laboratory (PNNL) on the Hanford Site. This report describes the inventory-based methods and provides the results for the assessment performed in 2003.
Date: December 5, 2003
Creator: Ballinger, Marcel Y.; Sula, Monte J.; Gervais, Todd L. & Edwards, Daniel L.
Object Type: Report
System: The UNT Digital Library
Association between severity of prescribed burns and subsequent activity of conifer-infesting beetles in stands of longleaf pine (open access)

Association between severity of prescribed burns and subsequent activity of conifer-infesting beetles in stands of longleaf pine

A randomized complete block experiment was performed to measure the effect of prescribed, dormant-season burns of three different levels of severity (measured as fuel consumption and soil surface heating) on subsequent insect infestation and mortality of mature longleaf pine (Pinus palustris Mill.). Multiple-funnel traps baited with a low release rate of turpentine and ethanol were used to monitor activity of certain coniferophagous beetles. Non-aggressive species, including the root beetles Hylastes salebrosus Eichhoff and H. tenuis Eichhoff, the ambrosia beetle Xyleborus pubescens Zimmermann, the reproduction weevil Pachylobius picivorus (Germar), and buprestid borers, were attracted to burned plots in numbers that correlated positively with burn severity. Beetle attraction to burned sites was greatest in the first weeks post-burn and disappeared by the second year. Two potential tree-killing bark beetles, Dendroctonus terebrans (Olivier) and Ips grandicollis (Eichhoff), were trapped in significant numbers but exhibited no attraction to burned plots. Tree mortality correlated significantly with the severity of the burns and amounted to 5% of stems in the hottest burn treatment after 3 years. The majority of the mortality was observed in the second and third years post-burn. Attacks of Ips and Dendroctonus bark beetles were apparent on nearly all dead or dying trees, …
Date: May 5, 2003
Creator: Sullivan, Brian, T; Fettig, C. J.; Otrosina, William, J.; Dalusky, Mark, J. & Berrisford, C.W.
Object Type: Article
System: The UNT Digital Library
Atomic resolution of lithium ions in LiCoO{sub 2} (open access)

Atomic resolution of lithium ions in LiCoO{sub 2}

LiCoO{sub 2} is the most common lithium storage material used as positive electrode in lithium rechargeable batteries. Ordering of lithium and vacancies has a profound effect on the physical properties of Li{sub x}CoO{sub 2} and the electrochemical performances of lithium batteries. An exit surface wave (ESW) phase image reconstructed from experimental images obtained on the LBNL One-Angstrom Microscope (OAM) shows all three types of atoms in LiCoO{sub 2}.
Date: June 5, 2003
Creator: Shao-Horn, Yang; Croguennec, Laurence; Delmas, Claude; Nelson, E. Chris & O'Keefe, Michael A.
Object Type: Article
System: The UNT Digital Library
CALIBRATION OF ONLINE ANALYZERS USING NEURAL NETWORKS (open access)

CALIBRATION OF ONLINE ANALYZERS USING NEURAL NETWORKS

Neural networks were used to calibrate an online ash analyzer at the Usibelli Coal Mine, Healy, Alaska, by relating the Americium and Cesium counts to the ash content. A total of 104 samples were collected from the mine, with 47 being from screened coal, and the rest being from unscreened coal. Each sample corresponded to 20 seconds of coal on the running conveyor belt. Neural network modeling used the quick stop training procedure. Therefore, the samples were split into training, calibration and prediction subsets. Special techniques, using genetic algorithms, were developed to representatively split the sample into the three subsets. Two separate approaches were tried. In one approach, the screened and unscreened coal was modeled separately. In another, a single model was developed for the entire dataset. No advantage was seen from modeling the two subsets separately. The neural network method performed very well on average but not individually, i.e. though each prediction was unreliable, the average of a few predictions was close to the true average. Thus, the method demonstrated that the analyzers were accurate at 2-3 minutes intervals (average of 6-9 samples), but not at 20 seconds (each prediction).
Date: December 5, 2003
Creator: Ganguli, Rajive; Walsh, Daniel E. & Yu, Shaohai
Object Type: Report
System: The UNT Digital Library
The CDF data handling system (open access)

The CDF data handling system

The Collider Detector at Fermilab (CDF) records proton-antiproton collisions at center of mass energy of 2.0 TeV at the Tevatron collider. A new collider run, Run II, of the Tevatron started in April 2001. Increased luminosity will result in about 1 PB of data recorded on tapes in the next two years. Currently the CDF experiment has about 260 TB of data stored on tapes. This amount includes raw and reconstructed data and their derivatives. The data storage and retrieval are managed by the CDF Data Handling (DH) system. This system has been designed to accommodate the increased demands of the Run II environment and has proven robust and reliable in providing reliable flow of data from the detector to the end user. This paper gives an overview of the CDF Run II Data Handling system which has evolved significantly over the course of this year. An outline of the future direction of the system is given.
Date: November 5, 2003
Creator: Litvintsev, Dmitry O.
Object Type: Article
System: The UNT Digital Library
Characterization and Operation of Liquid Crystal Adaptive Optics Phoropter (open access)

Characterization and Operation of Liquid Crystal Adaptive Optics Phoropter

Adaptive optics (AO), a mature technology developed for astronomy to compensate for the effects of atmospheric turbulence, can also be used to correct the aberrations of the eye. The classic phoropter is used by ophthalmologists and optometrists to estimate and correct the lower-order aberrations of the eye, defocus and astigmatism, in order to derive a vision correction prescription for their patients. An adaptive optics phoropter measures and corrects the aberrations in the human eye using adaptive optics techniques, which are capable of dealing with both the standard low-order aberrations and higher-order aberrations, including coma and spherical aberration. High-order aberrations have been shown to degrade visual performance for clinical subjects in initial investigations. An adaptive optics phoropter has been designed and constructed based on a Shack-Hartmann sensor to measure the aberrations of the eye, and a liquid crystal spatial light modulator to compensate for them. This system should produce near diffraction-limited optical image quality at the retina, which will enable investigation of the psychophysical limits of human vision. This paper describes the characterization and operation of the AO phoropter with results from human subject testing.
Date: February 5, 2003
Creator: Awwal, A.; Bauman, B.; Gavel, D.; Olivier, S.; Jones, S.; Hardy, J. L. et al.
Object Type: Article
System: The UNT Digital Library
Characterization of Plutonium, Neptunium, Strontium on Manganese Solids from Permanganate Reduction (open access)

Characterization of Plutonium, Neptunium, Strontium on Manganese Solids from Permanganate Reduction

This report reviews work relevant to Mn oxides and their use in radionuclide decontamination, focuses on the mechanism of radionuclide decontamination during permanganate treatment with simulant SRS HLW salt solutions and characterizes the solids that form.
Date: February 5, 2003
Creator: Duff, M.O.
Object Type: Report
System: The UNT Digital Library
Chemistry and Materials Science, A Collection of Articles from Science & Technology Review (open access)

Chemistry and Materials Science, A Collection of Articles from Science & Technology Review

None
Date: February 5, 2003
Creator: Diaz de la Rubia, T
Object Type: Report
System: The UNT Digital Library
Compressible Multiphase Flows in an ALE Framework (open access)

Compressible Multiphase Flows in an ALE Framework

None
Date: December 5, 2003
Creator: Stevens, David; Nelson, B.; Fogarty, P.; Eberle, C. & Ulrickson, M.
Object Type: Article
System: The UNT Digital Library
Concentric Titled Double-Helix Dipole Magnets (open access)

Concentric Titled Double-Helix Dipole Magnets

The high magnetic fields required for future accelerator magnets can only be achieved with Nb3Sn, other A15 or HTS type conductors, which are brittle and sensitive to mechanical strain. The traditional ''cosine-theta'' dipole configuration has intrinsic drawbacks that make it difficult and expensive to employ such conductors in these designs. Some of these problems involve (1) difficulty in applying enough pre-stress to counteract Lorentz forces without compromising conductor performance; (2) small minimum bend radii of the conductor necessitating the intricate wind-and-react coil fabrication; (3) complex spacers in particular for coil ends and expensive tooling for coil fabrication; (4) typically only 2/3 of the coil aperture can be used with achievable field uniformity.
Date: September 5, 2003
Creator: Meinke, Rainer; Goodzeit, Carl & Ball, Millicent
Object Type: Report
System: The UNT Digital Library
The Confinement Problem in Lattice Gauge Theory (open access)

The Confinement Problem in Lattice Gauge Theory

I review investigations of the quark confinement mechanism that have been carried out in the framework of SU(N) lattice gauge theory. The special role of Z(N) center symmetry is emphasized.
Date: March 5, 2003
Creator: Greensite, J.
Object Type: Article
System: The UNT Digital Library
Cross platform SCA component using C++ builder and KYLIX (open access)

Cross platform SCA component using C++ builder and KYLIX

A cross-platform component for EPICS Simple Channel Access (SCA) has been developed. EPICS client programs with GUI become portable at their C++ source-code level both on Windows and Linux by using Borland C++ Builder 6 and Kylix 3 on these platforms respectively.
Date: May 5, 2003
Creator: Nishimura, Hiroshi; Timossi, Chiris & McDonald, James L.
Object Type: Article
System: The UNT Digital Library
Design and Certification of Targets for Drop Tests at the NTRC Packaging Research Facility (open access)

Design and Certification of Targets for Drop Tests at the NTRC Packaging Research Facility

This report provides documentation of the design and certification of drop pad (targets) at the National Transportation Research Center (NTRC) Packaging Research Facility(PRF). Based on the evaluation performed, it has been demonstrated that the small (interior) drop pad (target) meets the regulatory definition of a flat, essentially unyielding, horizontal surface for packages weighing up to 3,150 lb (1,432 kg). The large (exterior) drop pad (target) meets the regulatory definition of a flat, essentially unyielding, horizontal surface for packages weighing up to 28,184 lb (12,811 kg).
Date: June 5, 2003
Creator: Ludwig, S. B.
Object Type: Report
System: The UNT Digital Library
Design and Test of Advanced Multi-Layer Dielectric Gratings for High Energy Petawatt (open access)

Design and Test of Advanced Multi-Layer Dielectric Gratings for High Energy Petawatt

In this paper we discuss recent work on the development of high damage threshold, high efficiency MLD (multilayer dielectric) diffraction gratings for use in high energy, petawatt laser systems. This effort involves a close integration between modeling, fabrication, and testing. The modeling work is used to identify grating designs that satisfy the constraints of high efficiency (>94%) and low field enhancement which is a necessary condition for high damage threshold. Subscale MLD gratings for test are being fabricated in an advanced ion-etch machine we have recently built. The testing effort is being conducted in a dedicated laboratory. The laser beam used to test the samples is based on an OPCPA (optical parametric chirped-pulse amplifier) and a compressor that can provide pulse energies up to 50mJ with pulse lengths variable from 0.3-20 ps. This test station is equipped with diagnostics to fully characterize both the spatial and temporal characteristics of the test beam at the plane of the sample. Initial results have demonstrated a dependence of damage threshold on incident angle that is in good agreement with the field enhancement calculations. We have demonstrated a grating design with a damage threshold of 3J/cm{sup 2} and are investigating manufacturability and reproducibility issues …
Date: September 5, 2003
Creator: Molander, W.; Komashko, A.; Britten, J.; Jones, L.; Brown, C.; Caird, J. et al.
Object Type: Article
System: The UNT Digital Library
Development of high Sensitivity Materials for Applications in Magneto-Mechanical Torque Sensor (open access)

Development of high Sensitivity Materials for Applications in Magneto-Mechanical Torque Sensor

The Matteucci effect, which mainly manifests itself as the change of magnetization of a material with torsional stress, is currently of great technological interest because of the search for magnetic torque sensors. Magnetic torque sensors are important to future improvements of automobiles and industrial robots. It is well known that the magnetic state of a material depends on both the external magnetic field and external stress which causes strain and change in magnetization of the material. The former phenomenon has been well understood in both theory and application. However, the magnetic state dependence of stress is not adequately understood and the experimental data is of limited extent. In this project, the Matteucci effect in iron, cobalt, nickel and permalloy rods has been documented when they were in magnetic remanence status along the axis and nickel ring when they were in remanence status along the circumference. The effect of annealing on the magnetomechanical effect in nickel and the temperature dependence of the magnetomechanical sensitivity has also been examined. Factors related to the sensitivity at equilibrium condition have been theoretically developed. it is found in the experiments that the mechanism of magnetic domain wall movement plays an important role rather than the …
Date: August 5, 2003
Creator: Shen, Yuping
Object Type: Thesis or Dissertation
System: The UNT Digital Library
DEVELOPMENT PRACTICES FOR OPTIMIZED MEOR IN SHALLOW HEAVY OIL RESERVOIRS (open access)

DEVELOPMENT PRACTICES FOR OPTIMIZED MEOR IN SHALLOW HEAVY OIL RESERVOIRS

The objective of this research project is to demonstrate an economically viable and sustainable method of producing shallow heavy oil reserves in western Missouri and southeastern Kansas, using an integrated approach including surface geochemical surveys, conventional MEOR treatments, horizontal fracturing in vertical wells, electrical resistivity tomography (ERT), and reservoir simulation to optimize the recovery process. The objective also includes transferring the knowledge gained from the project to other local landowners, to demonstrate how they may identify and develop their own heavy oil resources with minimal capital investment. Tasks completed in the first six-month period include soil sampling, geochemical analysis, construction of ERT arrays, collection of background ERT surveys, and analysis of core samples to develop a geomechanical model for designing the hydraulic fracturing treatment. Five wells were to be drilled in phase I. However, weather and funding delays resulted in drilling shifting to the second phase of the project. Work performed to date demonstrates that surface geochemical methods can be used to differentiate between productive and non-productive areas of the Warner Sand and that ERT can be used to successfully image through the Warner Sand.
Date: September 5, 2003
Creator: Dunn-Norman, Shari
Object Type: Report
System: The UNT Digital Library