A 4 to 0.1 nm FEL Based on the SLAC Linac (open access)

A 4 to 0.1 nm FEL Based on the SLAC Linac

The author show that using existing electron gun technology and a high energy linac like the one at SLAC, it is possible to build a Free Electron Laser operating around the 4 nm water window. A modest improvement in the gun performance would further allow to extend the FEL to the 0.1 nm region. Such a system would produce radiation with a brightness many order of magnitude above that of any synchrotron radiation source, existing or under construction, with laser power in the multigawatt region and subpicosecond pulse length.
Date: June 5, 2012
Creator: Pellegrini, C.
System: The UNT Digital Library
10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF (open access)

10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF

Pinhole-assisted point-projection backlighting with 10{micro}m and 5 {micro}m pinholes placed a small distance of order 1 mm away from the backlighter produces images with large field of view and high resolution. Pinholes placed closely to high-power backlighter sources can vaporize and close due to x-ray driven ablation, thereby limiting the usefulness of this method. A study of streaked 1-D backlit imaging of 25 {micro}m W wires using the OMEGA laser is presented. The pinhole closure timescale for 10 {micro}m pinholes placed 0.45 mm and 1 mm distant from the backlighter is 1.3 ns and 2.2 ns, respectively. Similar timescales for 5 {micro}m pinholes is also presented. Successful wire imaging prior to pinhole closure is clearly demonstrated.
Date: June 5, 2001
Creator: Bullock, A. B.; Landen, O. L. & Bradley, D. K.
System: The UNT Digital Library
Actinide (U-Th-Pa) concentrations and isotopic disequilibrium in surface soils and glassy fallout beads from historical nuclear tests (open access)

Actinide (U-Th-Pa) concentrations and isotopic disequilibrium in surface soils and glassy fallout beads from historical nuclear tests

None
Date: June 5, 2013
Creator: Eppich, G R; Knight, K B; Jacomb-Hood, T W; Hutcheon, I D & Spriggs, G D
System: The UNT Digital Library
ADAPTING A CERTIFIED SHIPPING PACKAGE FOR STORAGE APPLICATIONS (open access)

ADAPTING A CERTIFIED SHIPPING PACKAGE FOR STORAGE APPLICATIONS

For years shipping packages have been used to store radioactive materials at many DOE sites. Recently, the K-Area Material Storage facility at the Savannah River Site became interested in and approved the Model 9977 Shipping Package for use as a storage package. In order to allow the 9977 to be stored in the facility, there were a number of evaluations and modifications that were required. There were additional suggested modifications to improve the performance of the package as a storage container that were discussed but not incorporated in the design that is currently in use. This paper will discuss the design being utilized for shipping and storage, suggested modifications that have improved the storage configuration but were not used, as well as modifications that have merit for future adaptations for both the 9977 and for other shipping packages to be used as storage packages.
Date: June 5, 2012
Creator: Loftin, B. & Abramczyk, G.
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.
System: The UNT Digital Library
ADVANCES IN IMPEDANCE THEORY (open access)

ADVANCES IN IMPEDANCE THEORY

We review recent progress in the following areas of the impedance theory: calculation of impedance of tapers and small angle collimators; optical approximation and parabolic equation for the high-frequency impedance; impedance due to resistive inserts in a perfectly conducting pipe.
Date: June 5, 2009
Creator: Stupakov, G.
System: The UNT Digital Library
Ambient Radon-222 Monitoring in Amargosa Valley, Nevada (open access)

Ambient Radon-222 Monitoring in Amargosa Valley, Nevada

As part of a program to characterize and baseline selected environmental parameters in the region around the proposed repository at Yucca Mountain, Nevada, ambient radon-222 monitoring was conducted in the rural community of Amargosa Valley, the community closest to the proposed repository site. Passive integrating radon monitors and a continuous radon monitoring instrument were deployed adjacent to the Community Environmental Monitoring Program (CEMP) (http://www.cemp.dri.edu/index.html) station located in the Amargosa Valley Community Center near the library. The CEMP station provided real-time ambient gamma exposure and meteorological data used to correct the integrated radon measurements as well as verify meteorological data collected by the continuous radon monitoring instrument. Additionally, different types of environmental enclosures that housed the monitors and instrument were used to determine if particular designs influenced the ambient radon measurements.
Date: June 5, 2008
Creator: Karr, L. H.; Tappen, J. J.; Shafer, D. & Gray, K. J.
System: The UNT Digital Library
Analysis of Enriched Uranium and Weapons Plutonium Reloads for PWRs Using BRACC (open access)

Analysis of Enriched Uranium and Weapons Plutonium Reloads for PWRs Using BRACC

Comparisons of the multicycle results demonstrate that the correlation coefficients based on the CASMO3 data were implemented correctly and that the Linear Reactivity Model is acceptably accurate for missed reloads containing both uranium and weapons plutonium fuel. The expanded set of correlation coefficients make BRACC a useful tool for performing multi-cycle in-core fuel management studies of PWR cores containing weapons plutonium.
Date: June 5, 1997
Creator: Alonso, G. & Parish, T. A.
System: The UNT Digital Library
The Argonne boundary layer experiments facility : using minisodars to complement a wind profiler network. (open access)

The Argonne boundary layer experiments facility : using minisodars to complement a wind profiler network.

The Argonne Boundary Layer Experiments (ABLE) facility, located in south central Kansas, east of Wichita, is devoted primarily to investigations of and within the planetary boundary layer (PBL), including the dynamics of the mixed layer during both day and night; effects of varying land use and land form; the interactive role of precipitation, runoff, and soil moisture; storm development; and energy budgets on scales of 10 to 100 km. Located entirely within the Walnut River watershed, ABLE provides intense measurements within the northeast quadrant (Fig. 1) of the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) of the Atmospheric Radiation Measurement (ARM) Program (Stokes and Schwarz, 1994). By combining the continuous measurements of ABLE with ancillary continuous measurements of, for example, the ARM and the Global Energy Water cycle Experiment (GEWEX) (Kinster and Shukla, 1990) programs, ABLE provides a platform within which shorter, more intensive studies, such as those conducted by the Cooperative Atmosphere-Surface Exchange Studies (CASES) Program, can realize the full benefit of a wide variety of atmospheric measurements on many scales; this allows the study of hypothesized features of PBL development and dynamics, including frontal dynamics, nocturnal boundary development and breakdown, urban heat island effects, precipitation enhancement, …
Date: June 5, 1998
Creator: Coulter, R. L.
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.
System: The UNT Digital Library
Automated Low Frequency Load Cutoff (open access)

Automated Low Frequency Load Cutoff

None
Date: June 5, 2013
Creator: Top, P; Hussain, I; Clower, M; Barnard, R & Luong, N
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
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
System: The UNT Digital Library
Autophosphorylation of the DNA-Dependent Protein Kinase Catalyticsubunit is Required for Rejoining of DNA Double-Strand Breaks (open access)

Autophosphorylation of the DNA-Dependent Protein Kinase Catalyticsubunit is Required for Rejoining of DNA Double-Strand Breaks

This report is a descriptive journey of the Autophosphorylation of the DNA-Dependent Protein Kinase Catalyticsubunit is Required for Rejoining of DNA Double-Strand Breaks.
Date: June 5, 2002
Creator: Chan, Doug W.; Chen, Benjamin Ping-Chi; Yang, Shun-Jen; Singh,Sheela; Murphy, Michael B.; Kurimasa, Akihiro et al.
System: The UNT Digital Library
Bacterial Microcompartments (open access)

Bacterial Microcompartments

Bacterialmicrocompartments (BMCs) are organelles composed entirely of protein. They promote specific metabolic processes by encapsulatingand colocalizing enzymes with their substrates and cofactors, by protecting vulnerable enzymes in a defined microenvironment, and bysequestering toxic or volatile intermediates. Prototypes of the BMCsare the carboxysomes of autotrophic bacteria. However, structures of similarpolyhedral shape are being discovered in an ever-increasing number of heterotrophic bacteria, where they participate in the utilization ofspecialty carbon and energy sources.Comparative genomics reveals that the potential for this type of compartmentalization is widespread acrossbacterial phyla and suggests that genetic modules encoding BMCs are frequently laterally transferred among bacteria. The diverse functionsof these BMCs suggest that they contribute to metabolic innovation in bacteria in a broad range of environments.
Date: June 5, 2010
Creator: Kerfeld, Cheryl A.; Heinhorst, Sabine & Cannon, Gordon C.
System: The UNT Digital Library
Can combining economizers with improved filtration save energy and protect equipment in data centers? (open access)

Can combining economizers with improved filtration save energy and protect equipment in data centers?

Economizer use in data centers is an energy efficiency strategy that could significantly limit electricity demand in this rapidly growing economic sector. Widespread economizer implementation, however, has been hindered by potential equipment reliability concerns associated with exposing information technology equipment to particulate matter of outdoor origin. This study explores the feasibility of using economizers in data centers to save energy while controlling particle concentrations with high-quality air filtration. Physical and chemical properties of indoor and outdoor particles were analyzed at an operating northern California data center equipped with an economizer under varying levels of air filtration efficiency. Results show that when improved filtration is used in combination with an economizer, the indoor/outdoor concentration ratios for most measured particle types were similar to levels when using conventional filtration without economizers. An energy analysis of the data center reveals that, even during the summer months, chiller savings from economizer use greatly outweigh any increase in fan power associated with improved filtration. These findings indicate that economizer use combined with improved filtration could reduce data center energy demand while providing a level of protection from particles of outdoor origin similar to that observed with conventional design.
Date: June 5, 2009
Creator: Shehabi, Arman; Ganguly, Srirupa; Gundel, Lara A.; Horvath, Arpad; Kirchstetter, Thomas W.; Lunden, Melissa M. et al.
System: The UNT Digital Library
Commissioning the SPEAR3 Diagnostic Beamlines (open access)

Commissioning the SPEAR3 Diagnostic Beamlines

SPEAR3 has two diagnostic beam lines: an x-ray pinhole camera and a visible/UV beam line. The pinhole camera images {approx}8 keV dipole synchrotron radiation (SR) incident on a phosphor screen. The visible beam line delivers conventional optical radiation to an array of cameras and diagnostic elements on a 1x3m optical bench. This paper briefly reviews the pinhole camera system while concentrating more on visible beam line power transmission calculations and streak camera data. Impedance estimates in the nominal optics and bunch length measurements in low-alpha optics are presented.
Date: June 5, 2007
Creator: Corbett, W. J.; Limborg-Deprey, C.; Mok, W. Y. & Ringwall, A.
System: The UNT Digital Library
The compressibility of cubic white, orthorhombic black and rhombohedral black phosphorus (open access)

The compressibility of cubic white, orthorhombic black and rhombohedral black phosphorus

The effect of pressure on the crystal structure of white phosphorus has been studied up to 22.4 GPa. The {alpha} phase was found to transform into the {alpha}' phase at 0.87 {+-} 0.04 GPa with a volume change of 0.1 {+-} 0.3 cc/mol. A fit of a second order Birch-Murghanan equation to the data gave Vo = 16.94 {+-} 0.08 cc/mol and K{sub o} = 6.7 {+-} 0.5 GPa for the {alpha} phase and Vo = 16.4 {+-} 0.1 cc/mol and K{sub o} = 9.1 {+-} 0.3 GPa for the {alpha}' phase. The {alpha}' phase was found to transform to the A17 phase of black phosphorus at 2.68 {+-} 0.34 GPa and then with increasing pressure to the A7 and then simple cubic phase of black phosphorus. A fit of a second order Birch-Murnaghan equation to our orthorhombic and rhombohedral black phosphorus data gave Vo = 11.43 {+-} 0.02 cc/mol and K{sub o} = 34.7 {+-} 0.5 GPa for the A17 phase and Vo = 9.62 {+-} 0.01 cc/mol and K{sub o} = 65.0 {+-} 0.6 GPa for the A7 phase.
Date: June 5, 2009
Creator: Clark, S & Zaug, J M
System: The UNT Digital Library
Controlling the morphology of nanocrystal-polymer composites for solar cells (open access)

Controlling the morphology of nanocrystal-polymer composites for solar cells

None
Date: June 5, 2002
Creator: Huynh, Wendy U.; Dittmer, Janke J.; Libby, William C.; Whiting, Gregory L. & Alivisatos, A. Paul
System: The UNT Digital Library
Correlating Observations of Deformation Microstructures by TEM and Automated EBSD Techniques (open access)

Correlating Observations of Deformation Microstructures by TEM and Automated EBSD Techniques

The evolution of the deformed microstructure as a function of imposed plastic strain is of interest as it provides information on the material hardening characteristics and mechanism(s) by which cold work energy is stored. This has been extensively studied using transmission electron microscopy (TEM), where the high spatial and orientational resolution of the technique is used to advantage to study local phenomenon such as dislocation core structures and interactions of dislocations. With the recent emergence of scanning electron microscope (SEM) based automated electron backscatter diffraction (EBSD) techniques, it has now become possible to make mesoscale observations that are statistical in nature and complement the detailed TEM observations. Correlations of such observations will be demonstrated for the case of Ni-base alloys, which are typically non-cell forming solid solution alloys when deformed at ambient temperatures. For instance, planar slip is dominant at low strain levels but evolves into a microstructure where distinct crystallographic dislocation-rich walls form as a function of strain and grain orientation. Observations recorded using both TEM and EBSD techniques are presented and analyzed for their implication on subsequent annealing characteristics.
Date: June 5, 2000
Creator: Schwartz, A.J. & King, W.E.
System: The UNT Digital Library
csr impedance due to a bend magnet of finite length with a vacuum chamber of rectangular cross section (open access)

csr impedance due to a bend magnet of finite length with a vacuum chamber of rectangular cross section

We study the impedance due to coherent synchrotron radiation (CSR) generated by a short bunch of charged particles passing through a dipole magnet of finite length in a vacuum chamber of a given cross section. Our method represents a further development of the previous studies: we decompose the electromagnetic field of the beam over the eigenmodes of the toroidal chamber and derive a system of equations for the expansion coefficients in the series. We illustrate our general method by calculating the CSR impedance of a beam moving in a toroidal vacuum chamber of rectangular cross section.
Date: June 5, 2009
Creator: Stupakov, G. & Kotelnikov, I.A.
System: The UNT Digital Library
D0 - Anti-D0 Mixing And Search for CP Violation in D0 Decays using T-Odd Correlations at BaBar (open access)

D0 - Anti-D0 Mixing And Search for CP Violation in D0 Decays using T-Odd Correlations at BaBar

None
Date: June 5, 2013
Creator: Bellis, Matthew
System: The UNT Digital Library
Demonstration of 12 nm resolution Fresnel zone plate lens based soft x-ray microscopy (open access)

Demonstration of 12 nm resolution Fresnel zone plate lens based soft x-ray microscopy

To extend soft x-ray microscopy to a resolution of order 10 nm or better, we developed a new nanofabrication process for Fresnel zone plate lenses. The new process, based on the double patterning technique, has enabled us to fabricate high quality gold zone plates with 12 nm outer zones. Testing of the zone plate with the full-field transmission x-ray microscope, XM-1, in Berkeley, showed that the lens clearly resolved 12 nm lines and spaces. This result represents a significant step towards 10 nm resolution and beyond.
Date: June 5, 2009
Creator: Chao, W.; Kim, J.; Rekawa, S.; Fischer, P. & Anderson, E. H.
System: The UNT Digital Library
Design and Construction of a Gamma Reaction History Diagnostic for the National Ignition Facility (open access)

Design and Construction of a Gamma Reaction History Diagnostic for the National Ignition Facility

Gas Cherenkov detectors have been used to convert fusion gammas into photons to achieve gamma reaction history (GRH) measurements. These gas detectors include a converter, pressurized gas volume, relay optics, and a photon detector. A novel design for the National Ignition Facility (NIF) using 90º Off-Axis Parabolic mirrors efficiently collects signal from fusion gammas with 8-ps time dispersion.1 Fusion gammas are converted to Compton electrons, which generate broadband Cherenkov light (our response is from 250 to 700 nm) in a pressurized gas cell. This light is relayed into a high-speed detector using three parabolic mirrors. The detector optics collect light from a 125-mm-diameter by 600-mm-long interchangeable gas (CO2 or SF6) volume. Because light is collected from source locations throughout the gas volume, the detector is positioned at the stop position rather than at an image position. The stop diameter and its position are independent of the light-generation locations along the gas cell. This design incorporates a fixed time delay that allows the detector to recover from prompt radiation. Optical ray tracings demonstrate how light can be collected from different angled trajectories of the Compton electrons as they traverse the gas volume. A Monte Carlo model of the conversion process from …
Date: June 5, 2009
Creator: R.M. Malone, B.C. Cox, B.C. Frogget, M.I. Kaufman, T.W. Tunnell; H.W. Herrmann, S.C. Evans, J.M. Mack, C.S. Young & Stoeffl, W.
System: The UNT Digital Library