Relative x-ray backlighter intensity comparison of ti and ti/sc combination foils driven in double-sided and single-sided laser configuration (open access)

Relative x-ray backlighter intensity comparison of ti and ti/sc combination foils driven in double-sided and single-sided laser configuration

Use of multiple backlighter foils and/or double-sided laser interaction geometry with backlit imaging can result in improved backlighter efficiency. An experimental comparison of backlighter intensity for Ti foils and Ti/Sc combination foils in both the one-sided and double-sided laser-interaction configuration is presented. Spectrally-integrated framing camera images show intensity contributions of front and rear backlighter surfaces for both foil types. Analysis of time-resolved x-ray spectra collected from foil targets show the relative contribution of Ti and Sc 2-1 He-like resonance lines to the total backlighter intensity.
Date: June 5, 2000
Creator: Bullock, A. B.; Landen, O. L. & Bradley, D. K.
Object Type: Article
System: The UNT Digital Library
Simulation of Detonation Problems with MLS Grid Free Methodology (open access)

Simulation of Detonation Problems with MLS Grid Free Methodology

The MLS grid free rezone method, a simple, flexible finite difference method to solve general mechanics problems, especially detonation problems, is proposed in this paper. The spatial points that carry time dependent data are distributed in space in such a way that provides nearly uniform spacing of points, accurate presentation of boundaries, easy variation of resolutions and arbitrary deletion of irrelevant regions. Local finite difference operators are obtained with simple MLS differentiation. There is no specific topological or geometrical restriction with the distribution of data points. Therefore this method avoids many drawbacks of the traditional CFD methods. Because of its flexibility, it can be used to simulate a wide range of mechanics problems. Because of its simplicity, it has the potential to become a preferred method. Most traditional CFD methods, from a SPH view, can be considered as special cases of grid free methods of specific kernel functions. Such a generalization allows the development of a unified grid free CFD code that can be switched to various CFD methods by switching the kernel functions. Because of the flexibility in management and simplicity of coding, such a unified code is desired.
Date: June 5, 2002
Creator: Yao, J; Gunger, M E & Matuska, D A
Object Type: Article
System: The UNT Digital Library
NON-SCALING FIXED FIELD GRADIENT ACCELERATOR (FFAG) DESIGN FOR THE PROTON AND CARBON THERAPY. (open access)

NON-SCALING FIXED FIELD GRADIENT ACCELERATOR (FFAG) DESIGN FOR THE PROTON AND CARBON THERAPY.

The non-scaling Fixed Field Alternating Gradient (FFAG-from now on) accelerator provides few advantages with respect to the other fixed field accelerators like CYCLOTRONS or scaling-FFAG's. One of the advantages is smaller required aperture due to small orbit offsets during acceleration. The large and heavy magnets are avoided. The beam is very well controlled in a strong focusing regime. This concept has been extensively investigated during the last eight FFAG workshops in Japan, USA, Canada, and CERN in Europe.
Date: June 5, 2005
Creator: Trbojevic, D.; Keil, E. & Sessler, A.
Object Type: Article
System: The UNT Digital Library
NIF Power Conditioning System Testing at LLNL (open access)

NIF Power Conditioning System Testing at LLNL

The National Ignition Facility (NIF) is now under construction at the Lawrence Livermore National Laboratory (LLNL). The Power Conditioning System (PCS) for NIF, when completed will consist of a 192 nearly identical 2 megajoule capacitor storage banks driving 7680 two meter long flashlamps. A fully integrated single-module test facility was completed in August of 2000 at LLNL. The purpose to the Test Facility is to conduct Reliability and Maintainability (RAM) testing of a true ''First Article'' system (built to the final drawing package as opposed to a prototype). The test facility can be fired once every ten minutes with a total peak output current of 580kA with a pulse width of 400us. To date over 4000 full power shots have been conducted at this facility.
Date: June 5, 2001
Creator: Fulkerson, E S; Newton, M; Hulsey, s; Hammon, J & Moore, W
Object Type: Article
System: The UNT Digital Library
Automated Test System for NIF Flashlamps (open access)

Automated Test System for NIF Flashlamps

This paper describes design and operation of the flashlamp test system, used to evaluate the primary laser flashlamps on the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The tester delivers repetitive high voltage pulses to a series pair of flashlamps at levels closely simulating those encountered in normal operation. Each lamp pair is subjected to a pre-ionization and main pulse shot sequence, with two minute intervals between shots. This capability allows the manufacturer to test and evaluate the flashlamps for infant mortality and longevity before delivery to NIF. All operations are under computer control with fully automated test and data acquisition capabilities requiring minimal operator input. The system is designed to operate continuously. Typical pre-ionization and main pulse outputs are: (1) Pre-ionization Pulse--V{sub chg} = 27kV, I{sub peak} = 3kA, E = 2.4kJ; Pulse Width--(10%-90%) - 200us; Main Pulse--V{sub chg} = 23kV, I{sub peak} - 24kA, E - 78.6kJ; and Pulse Width--(10%-90%) - 350us.
Date: June 5, 2001
Creator: da Silva, T; Creely, P; Hammon, J; Shaw, R; Boyle, R T & Fulkerson, E S
Object Type: Article
System: The UNT Digital Library
Energetic Nanocomposites with Sol-gel Chemistry: Synthesis, Safety, and Characterization (open access)

Energetic Nanocomposites with Sol-gel Chemistry: Synthesis, Safety, and Characterization

The preparation and characterization of energetic composite materials containing nanometer-sized constituents is currently a very active and exciting area of research at laboratories around the world. Some of these efforts have produced materials that have shown very unique and important properties relative to traditional energetic materials. We have previously reported on the use of sol-gel chemical methods to prepare energetic nanocomposites. Primarily we reported on the sol-gel method to synthesize nanometer-sized ferric oxide that was combined with aluminum fuel to make pyrotechnic nanocomposites. Since then we have developed a synthetic approach that allows for the preparation of hybrid inorganic/organic energetic nanocomposites. This material has been characterized by thermal methods, energy-filtered transmission electron microscopy (EFTEM), N{sub 2} adsorption/description methods, and Fourier-Transform (FT-IR) spectroscopy, results of which will be discussed. According to these characterization methods the organic polymer phase fills the nanopores of the composite material, providing superb mixing of the component phases in the energetic nanocomposite. The EFTEM results provide a convenient and effective way to evaluate the intimacy of mixing between these component phases. The safe handling and preparation of energetic nanocomposites is of paramount importance to this research and we will report on studies performed to ensure such.
Date: June 5, 2002
Creator: Gash, A. E.; Simpson, R. L. & Satcher, J. H.
Object Type: Article
System: The UNT Digital Library
PLANS FOR KAON PHYSICS AT BNL. (open access)

PLANS FOR KAON PHYSICS AT BNL.

The author gives an overview of current plans for kaon physics at BNL. The program is centered around the rare decay modes K{sup +} {yields} {pi}{sup +}{nu}{bar {nu}} and K{sub L} {yields} {pi}{sup 0}{nu}{bar {nu}}.
Date: June 5, 2004
Creator: REDLINGER,G.
Object Type: Article
System: The UNT Digital Library
Advanced Techniques for In-Situ Monitoring of Phase Transformations During Welding Using Synchrotron-Based X-Ray Diffraction (open access)

Advanced Techniques for In-Situ Monitoring of Phase Transformations During Welding Using Synchrotron-Based X-Ray Diffraction

Understanding the evolution of microstructure in welds is an important goal of welding research because of the strong correlation between weld microstructure and weld properties. To achieve this goal it is important to develop a quantitative measure of phase transformations encountered during welding in order to ultimately develop methods for predicting weld microstructures from the characteristics of the welding process. To aid in this effort, synchrotron radiation methods have been developed at Lawrence Livermore National Laboratory (LLNL) for direct observation of microstructure evolution during welding. Using intense, highly collimated synchrotron radiation, the atomic structure of the weld heat affected and fusion zones can be probed in real time. Two synchrotron-based techniques, known as spatially resolved (SRXRD) and time resolved (TRXRD) x-ray diffraction, have been developed for these investigations. These techniques have now been used to investigate welding induced phase transformations in titanium alloys, low alloy steels, and stainless steel alloys. This paper will provide a brief overview of these methods and will discuss microstructural evolution during the welding of low carbon (AISI 1005) and medium carbon (AISI 1045) steels where the different levels of carbon influence the evolution of microstructures during welding.
Date: June 5, 2005
Creator: Elmer, J. W.; Palmer, T. A.; Zhang, W. & DebRoy, T.
Object Type: Article
System: The UNT Digital Library
Letter of intent to build an off-axis detector to study nu(mu) ---> nu(e) oscillations with the NuMI neutrino beam (open access)

Letter of intent to build an off-axis detector to study nu(mu) ---> nu(e) oscillations with the NuMI neutrino beam

None
Date: June 5, 2006
Creator: Ayres, D.; Drake, G.; Goodman, M.; Guarino, V.; Joffe-Minor, T.; Reyna, D. et al.
Object Type: Report
System: The UNT Digital Library
Manganin Gauge and Reactive Flow Modeling Study of the Shock Initiation of PBX 9501 (open access)

Manganin Gauge and Reactive Flow Modeling Study of the Shock Initiation of PBX 9501

A series of 101mm diameter gas gun experiments was fired using manganin pressure gauges embedded in the HMX-based explosive PBX 9501 at initial temperatures of 20 C and 50 C. Flyer plate impact velocities were chosen to produce impact pressure levels in PBX 9501 at which the growth of explosive reaction preceding detonation was measured on most of the gauges and detonation pressure profiles were recorded on some of the gauges placed deepest into the explosive targets. All measured pressure histories for initial temperatures of 25 C and 50 C were essentially identical. Measured run distances to detonation at several input shock pressures agreed with previous results. An existing ignition and growth reactive flow computer model for shock initiation and detonation of PBX 9501, which was developed based on LANL embedded particle velocity gauge data, was tested on these pressure gauge results. The agreement was excellent, indicating that the embedded pressure and particle velocity gauge techniques yielded consistent results.
Date: June 5, 2001
Creator: Tarver, C M; Forbes, J W; Garcia, F & Urtiew, P A
Object Type: Article
System: The UNT Digital Library
An Overview of Neutrino Masses and Mixing in SO(10) Models. (open access)

An Overview of Neutrino Masses and Mixing in SO(10) Models.

We review in this talk various SUSY SO(10) models. Specifically, we discuss how small neutrino masses are generated in and generic predictions of different SO(10) models. A comparison of the predictions of these models for sin{sup 2} {theta}{sub 13}is given.
Date: June 5, 2003
Creator: Chen, M. C. & Mahanthappa, K. T.
Object Type: Article
System: The UNT Digital Library
Automatic Extraction of Closed Pixel Clusters for Target Cueing in Hyperspectral Images (open access)

Automatic Extraction of Closed Pixel Clusters for Target Cueing in Hyperspectral Images

Traditional algorithms for automatic target cueing (ATC) in hyperspectral images, such as the RX algorithm, treat anomaly detection as a simple hypothesis testing problem. Each decision threshold gives rise to a different set of anomalous pixels. The clustered Rx algorithm generates target cues by grouping anomalous pixels into spatial clusters, and retaining only those clusters that satisfy target specific spatial constraints. It produces one set of target cues for each of several decision thresholds, and conservatively requires {Omicron}(K{sup 2}) operations per pixel, where K is the number of spectral bands (which varies from hundreds to thousands in hyperspectral images). A novel ATC algorithm, known as ''Pixel Cluster Cueing'' (PCC), is discussed. PCC groups pixels into clusters based on spectral similarity and spatial proximity, and then selects only those clusters that satisfy target-specific spatial constraints as target cues. PCC requires only {Omicron}(K) operations per pixel, and it produces only one set of target cues because it is not an anomaly detection algorithm, i.e., it does not use a decision threshold to classify individual pixels as anomalies. PCC is compared both computationally and statistically to the RX algorithm.
Date: June 5, 2001
Creator: Paglieroni, D W & Perkins, D E
Object Type: Article
System: The UNT Digital Library
The Specification of Source-to-source Transformations for the Compile-time Optimization of Parallel Object-oriented Scientific Applications (open access)

The Specification of Source-to-source Transformations for the Compile-time Optimization of Parallel Object-oriented Scientific Applications

The performance of object-oriented applications in scientific computing often suffers from the inefficient use of high-level abstractions provided by underlying libraries. Since these library abstractions are not part of the programming language itself there is no compiler mechanism to respect their semantics and thus to perform appropriate optimizations, e.g., array semantics within object-oriented array class libraries which permit parallel optimizations inconceivable to the serial compiler. We have presented the ROSE infrastructure as a tool for automatically generating library-specific preprocessors. These preprocessors can perform sematics-based source-to-source transformations of the application in order to introduce high-level code optimizations. In this paper we outline the design of ROSE and focus on the discussion of various approaches for specifying and processing complex source code transformations. These techniques are supposed to be as easy and intuitive as possible for the ROSE users, i.e. for the designers of the library-specific preprocessors.
Date: June 5, 2001
Creator: Quinlan, D & Kowarschik, M
Object Type: Article
System: The UNT Digital Library
Modeling The Effect of Drifts on the Edge, Scrape-Off Layer, and Divertor Plasma in DIII-D (open access)

Modeling The Effect of Drifts on the Edge, Scrape-Off Layer, and Divertor Plasma in DIII-D

Simulations of plasmas with a DIII-D shape indicate plasma drifts are important at power levels near the L- to H-mode plasma transition. In addition to enhancing plasma flows in the divertor region, drifts are found to play a key role in establishing highly sheared radial electric fields in the edge of the confined plasma, for the physics of the high confinement operating mode (H-mode). Measurements of the plasma structure in the vicinity of the X-point of DIII-D indicate the importance of drifts on plasma flow between the scrape-off layer (SOL) and closed field lines. The large electric fields provide large flows around the X-point, and these are conjectured to play a role in the transition from L- to H-mode confinement. These results indicate the relevance of modeling the edge and SOL plasmas of present tokamak devices using models which include E x B, {del}B, and pressure gradient drifts. The results of simulation of specific DIII-D discharges is reported in this paper. They start with discussion of the simulation of an Ohmic discharge in Section 2, including a study of the effect of varying several operational parameters. Simulation of a higher triangularity L-mode discharge is discussed in Section, and a summary …
Date: June 5, 2001
Creator: Porter, G. D.; Boedo, J. A.; Groebner, R. J.; Carlstrom, T. N.; Rognlien, T. D.; Rensink, M. E. et al.
Object Type: Article
System: The UNT Digital Library
Shock Initiation of UF-TATB at 250(degree)C (open access)

Shock Initiation of UF-TATB at 250(degree)C

The shock initiation properties of pure ultrafine grade triaminotrinitrobenzne (UF-TATB) pressed to an initial density of 1.80 g/cm{sup 3} and fired at ambient temperature and 250 C are reported. Embedded manganin pressure gauges are used to measure the pressure histories during the buildup to detonation at several input pressures. The ambient temperature results confirm previous run distance to detonation versus shock pressure results. UF-TATB at 250 C is shown to be much more shock sensitive than it is at ambient temperature. At high impact pressures, the shock sensitivity of UF-TATB at 250 C approaches that of HMX-based explosives under ambient conditions. Ignition and Growth reactive flow models are developed for UF-TATB at both temperatures to allow predictions to be made for other scenarios.
Date: June 5, 2001
Creator: Urtiew, P A; Forbes, J W; Garcia, F & Tarver, C M
Object Type: Article
System: The UNT Digital Library
A New Technique for Troubleshooting Large Capacitive Energy Storage Banks (open access)

A New Technique for Troubleshooting Large Capacitive Energy Storage Banks

The Power Conditioning System (PCS) of the National Ignition Facility (NIF) like many pulse power systems relies on large numbers of inductively isolated high voltage capacitors configured in parallel for energy storage. When an energy storage capacitor fails in such a capacitor bank, there is often little or no external indication showing which capacitor failed. Identifying the failed component can be a time consuming and potentially hazardous operation. Conventional methods using capacitance meters require that each capacitor be disconnected and tested independently. They have developed a new non-invasive technique (i.e. no dismantling of the bank is required) that greatly improves personnel safety as well reducing troubleshooting time.
Date: June 5, 2001
Creator: Fulkerson, S E & Hammon, J
Object Type: Article
System: The UNT Digital Library
Standard Formats for Atomic Data: the APED (open access)

Standard Formats for Atomic Data: the APED

Standardized formats for atomic data used in calculating emission from a collisionally-ionized plasma are described. The formats use the astronomical-standard FITS format, and are extendible to other purposes, such as photoionization data. The formats emphasize storing references to the original data source and keeping the data in as-received form, to aid in checking against the original literature.
Date: June 5, 2001
Creator: Smith, R K; Brickhouse, N S; Liedahl, D A & Raymond, J C
Object Type: Article
System: The UNT Digital Library
Network Sensitivity Solutions for Regional Moment Tensor Inversions (open access)

Network Sensitivity Solutions for Regional Moment Tensor Inversions

Well-resolved moment tensor solutions reveal information about the sources of seismic waves. Here we introduce a new way of assessing confidence in the regional full moment tensor inversion via the introduction of the network sensitivity solution (NSS). The NSS takes into account the unique station distribution, frequency band, and signal-to-noise ratio of a given event scenario. The NSS compares both a hypothetical pure source (for example an explosion or an earthquake) and the actual data with several thousand sets of synthetic data from a uniform distribution of all possible sources. The comparison with a hypothetical pure source provides the theoretically best-constrained source-type region for a given set of stations, and with it one can determine whether further analysis with the data is warranted. The NSS that employs the actual data gives a direct comparison of all other source-types with the best-fit source. In this way, one can choose a threshold level of fit where the solution is comfortably constrained. The method is tested for the well-recorded nuclear test, JUNCTION, at the Nevada Test Site. Sources that fit comparably well to a hypothetical pure explosion recorded with no noise at the JUNCTION data stations have a large volumetric component and are …
Date: June 5, 2009
Creator: Ford, S R; Dreger, D S & Walter, W R
Object Type: Article
System: The UNT Digital Library
Non-Axisymmetric Shaping of Tokamaks Preserving Quasi-Axisymmetry (open access)

Non-Axisymmetric Shaping of Tokamaks Preserving Quasi-Axisymmetry

If quasi-axisymmetry is preserved, non-axisymmetric shaping can be used to design tokamaks that do not require current drive, are resilient to disruptions, and have robust plasma stability without feedback. Suggestions for addressing the critical issues of tokamaks can only be validated when presented with sufficient specificity that validating experiments can be designed. The purpose of this paper is provide that specificity for non-axisymmetric shaping. To our knowledge, no other suggestions for the solution of a number of tokamak issues, such as disruptions, have reached this level of specificity. Sequences of three-field-period quasi-axisymmetric plasmas are studied. These sequences address the questions: (1) What can be achieved at various levels of non-axisymmetric shaping? (2) What simplifications to the coils can be achieved by going to a larger aspect ratio? (3) What range of shaping can be achieved in a single experimental facility? The sequences of plasmas found in this study provide a set of interesting and potentially important configurations.
Date: June 5, 2009
Creator: Boozer, Long-Poe Ku and Allen H.
Object Type: Report
System: The UNT Digital Library
X-ray Diffraction Crystal Calibration and Characterization (open access)

X-ray Diffraction Crystal Calibration and Characterization

National Security Technologies’ X-ray Laboratory is comprised of a multi-anode Manson type source and a Henke type source that incorporates a dual goniometer and XYZ translation stage. The first goniometer is used to isolate a particular spectral band. The Manson operates up to 10 kV and the Henke up to 20 kV. The Henke rotation stages and translation stages are automated. Procedures have been developed to characterize and calibrate various NIF diagnostics and their components. The diagnostics include X-ray cameras, gated imagers, streak cameras, and other X-ray imaging systems. Components that have been analyzed include filters, filter arrays, grazing incidence mirrors, and various crystals, both flat and curved. Recent efforts on the Henke system are aimed at characterizing and calibrating imaging crystals and curved crystals used as the major component of an X-ray spectrometer. The presentation will concentrate on these results. The work has been done at energies ranging from 3 keV to 16 keV. The major goal was to evaluate the performance quality of the crystal for its intended application. For the imaging crystals we measured the laser beam reflection offset from the X-ray beam and the reflectivity curves. For the curved spectrometer crystal, which was a natural crystal, …
Date: June 5, 2009
Creator: Haugh, Michael J.; Stewart, Richard & Kugland, Nathan
Object Type: Article
System: The UNT Digital Library
DEVELOPMENT OF THE H1700 SHIPPING PACKAGE (open access)

DEVELOPMENT OF THE H1700 SHIPPING PACKAGE

The H1700 Package is based on the DOE-EM Certified 9977 Packaging. The H1700 will be certified by the Packaging Certification Division of the National Nuclear Security Administration for the shipment of plutonium by air by the United Stated Military both within the United States and internationally. The H1700 is designed to ship radioactive contents in assemblies of Radioisotope Thermoelectric Generators (RTGs) or arrangements of nested food-pack cans. The RTG containers are designed and tested to remain leaktight during transport, handling, and storage; however, their ability to remain leaktight during transport in the H1700 is not credited. This paper discusses the design and special operation of the H1700.
Date: June 5, 2009
Creator: Abramczyk, G.; Loftin, B. & Mann, P.
Object Type: Article
System: The UNT Digital Library
High Performance, Three-Dimensional Bilateral Filtering (open access)

High Performance, Three-Dimensional Bilateral Filtering

Image smoothing is a fundamental operation in computer vision and image processing. This work has two main thrusts: (1) implementation of a bilateral filter suitable for use in smoothing, or denoising, 3D volumetric data; (2) implementation of the 3D bilateral filter in three different parallelization models, along with parallel performance studies on two modern HPC architectures. Our bilateral filter formulation is based upon the work of Tomasi [11], but extended to 3D for use on volumetric data. Our three parallel implementations use POSIX threads, the Message Passing Interface (MPI), and Unified Parallel C (UPC), a Partitioned Global Address Space (PGAS) language. Our parallel performance studies, which were conducted on a Cray XT4 supercomputer and aquad-socket, quad-core Opteron workstation, show our algorithm to have near-perfect scalability up to 120 processors. Parallel algorithms, such as the one we present here, will have an increasingly important role for use in production visual analysis systems as the underlying computational platforms transition from single- to multi-core architectures in the future.
Date: June 5, 2008
Creator: Bethel, E. Wes
Object Type: Report
System: The UNT Digital Library
Plasma Diagnostic Calibration and Characterizations with High Energy X-rays (open access)

Plasma Diagnostic Calibration and Characterizations with High Energy X-rays

National Security Technologies’ High Energy X-ray (HEX) Facility is unique in the U.S. Department of Energy complex. The HEX provides fluorescent X-rays of 5 keV to 100 keV with fluence of 10^5–10^6 photons/cm^2/second at the desired line energy. Low energy lines can be filtered, and both filters and fluorescers can be changed rapidly. We present results of calibrating image plates (sensitivity and modulation transfer function), a Bremsstrahlung spectrometer (stacked filters and image plates), and the National Ignition Facility’s Filter- Fluorescer Experiment (FFLEX) high energy X-ray spectrometer. We also show results of a scintillator light yield and alignment study for a neutron imaging system.
Date: June 5, 2009
Creator: Ali, Zaheer
Object Type: Article
System: The UNT Digital Library
Gamma Reaction History for the NIF (open access)

Gamma Reaction History for the NIF

Bang time and reaction history measurements are fundamental components of diagnosing ICF implosions and will be essential contributors to diagnosing attempts at ignition on the National Ignition Facility (NIF). Fusion gammas provide a direct measure of fusion interaction rate without being compromised by Doppler spreading. Gamma-based gas Cherenkov detectors that convert fusion gamma rays to optical Cherenkov photons for collection by fast recording systems have been developed and fielded at Omega. These systems have established their usefulness in illuminating ICF physics in several experimental campaigns. Bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF System Design Requirements. A staged approach of implementing Gamma Reaction History (GRH) diagnostics on the NIF has been initiated. In the early stage, multiple detectors located close to target chamber center (at 2 and 6 m) and coupled to photomultiplier tubes are geared toward the loweryield THD campaign. In the later stage, streak camera–coupled instruments will be used for improved temporal resolution at the higher yields expected from the DT ignition campaign. Multiple detectors will allow for increased dynamic range and gamma energy spectral information.
Date: June 5, 2009
Creator: Herrmann, H. W.; Evans, S. C.; Kim, Y.; Mack, J. M.; Young, C. S.; Cox, B. C. et al.
Object Type: Article
System: The UNT Digital Library