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.
Object Type: Article
System: The UNT Digital Library
10 CFR 850 Implementation of Requirements (open access)

10 CFR 850 Implementation of Requirements

10 CFR 850 defines a contractor as any entity, including affiliated entities, such as a parent corporation, under contract with DOE, including a subcontractor at any tier, with responsibility for performing work at a DOE site in furtherance of a DOE mission. The Chronic Beryllium Disease Prevention Program (CBDPP) applies to beryllium-related activities that are performed at the Lawrence Livermore National Laboratory (LLNL). The CBDPP or Beryllium Safety Program is integrated into the LLNL Worker Safety and Health Program and, thus, implementation documents and responsibilities are integrated in various documents and organizational structures. Program development and management of the CBDPP is delegated to the Environment, Safety and Health (ES&H) Directorate, Worker Safety and Health Functional Area. As per 10 CFR 850, Lawrence Livermore National Security, LLC (LLNS) periodically submits a CBDPP to the National Nuclear Security Administration/Livermore Site Office (NNSA/LSO). The requirements of this plan are communicated to LLNS workers through ES&H Manual Document 14.4, 'Working Safely with Beryllium.' 10 CFR 850 is implemented by the LLNL CBDPP, which integrates the safety and health standards required by the regulation, components of the LLNL Integrated Safety Management System (ISMS), and incorporates other components of the LLNL ES&H Program. As described in …
Date: January 5, 2012
Creator: Lee, S.
Object Type: Report
System: The UNT Digital Library
Ab-initio calculation of optical properties of wurtzitic In_x Ga_1x N and In_x Al_1x N alloys including excitonic effects (open access)

Ab-initio calculation of optical properties of wurtzitic In_x Ga_1x N and In_x Al_1x N alloys including excitonic effects

None
Date: September 5, 2012
Creator: de Carvalho, L C; Schleife, A; Furthmueller, J & Bechstedt, F
Object Type: Article
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.
Object Type: Article
System: The UNT Digital Library
Advances in X-Band TW Accelerator Structures Operating in the 100 MV/M Regime (open access)

Advances in X-Band TW Accelerator Structures Operating in the 100 MV/M Regime

A CERN-SLAC-KEK collaboration on high gradient X-band accelerator structure development for CLIC has been ongoing for three years. The major outcome has been the demonstration of stable 100 MV/m gradient operation of a number of CLIC prototype structures. These structures were fabricated using the technology developed from 1994 to 2004 for the GLC/NLC linear collider initiative. One of the goals has been to refine the essential parameters and fabrication procedures needed to realize such a high gradient routinely. Another goal has been to develop structures with stronger dipole mode damping than those for GLC/NLC. The latter requires that the surface temperature rise during the pulse be higher, which may increase the breakdown rate. One structure with heavy damping has been RF processed and another is nearly finished. The breakdown rates of these structures were found to be higher by two orders of magnitude compared to those with equivalent acceleration mode parameters but without the damping features. This paper presents these results together with some of the earlier results from non-damped structures.
Date: July 5, 2012
Creator: Higo, Toshiyasu; Higashi, Yasuo; Matsumoto, Shuji; Yokoyama, Kazue; Adolphsen, Chris; Dolgashev, Valery et al.
Object Type: Article
System: The UNT Digital Library
Analysis of Deformation Twinning in Tantalum Single Crystals Under Shock Loading Conditions (open access)

Analysis of Deformation Twinning in Tantalum Single Crystals Under Shock Loading Conditions

None
Date: December 5, 2012
Creator: Florando, J. N.; Barton, N. R.; El-Dasher, B.; McNaney, J. M. & Kumar, M.
Object Type: Article
System: The UNT Digital Library
Analysis on linac quadrupole misalignment in FACET commissioning 2012 (open access)

Analysis on linac quadrupole misalignment in FACET commissioning 2012

In this note, the analysis on linac quadrupole misalignment is presented for the FACET linac section LI05-09 plus LI11-19. The effectiveness of the beam-based alignment technique is preliminarily confirmed by the measurement. Beam-based alignment technique was adopted at SLAC linac since SLC time. Here the beam-based alignment algorithms are further developed and applied in the FACET commissioning during 2012 run.
Date: July 5, 2012
Creator: Sun, Yipeng
Object Type: Report
System: The UNT Digital Library
The BBSOLVE Users Manual Version 1.0 (open access)

The BBSOLVE Users Manual Version 1.0

N/A
Date: December 5, 2012
Creator: M., Blaskiewicz
Object Type: Report
System: The UNT Digital Library
Beyond DVFS: A First Look at Performance Under a Hardware-Enforced Power Bound (open access)

Beyond DVFS: A First Look at Performance Under a Hardware-Enforced Power Bound

None
Date: March 5, 2012
Creator: Rountree, B. R.; Ahn, D. H.; de Supinski, B. R.; Lowenthal, D. K. & Schulz, M.
Object Type: Article
System: The UNT Digital Library
BOUT simulations of drift resistive ballooning L-mode turbulence in the edge of the DIII-D tokamak (open access)

BOUT simulations of drift resistive ballooning L-mode turbulence in the edge of the DIII-D tokamak

None
Date: November 5, 2012
Creator: Cohen, B. I.; Umansky, M. V.; Nevins, W. M.; Makowski, M.; Boedo, J.; Rudakov, D. et al.
Object Type: Article
System: The UNT Digital Library
Brute Force Modeling of the Kessler Syndrome (open access)

Brute Force Modeling of the Kessler Syndrome

None
Date: September 5, 2012
Creator: Nikolaev, S.; Phillion, D.; Springer, H. K.; deVries, W.; Jiang, M.; Pertica, A. et al.
Object Type: Article
System: The UNT Digital Library
Change Management Project award submission (open access)

Change Management Project award submission

None
Date: December 5, 2012
Creator: Teslich, R
Object Type: Article
System: The UNT Digital Library
Characterization of fundamental catalytic properties of MoS2/WS2 nanotubes and nanoclusters for desulfurization catalysis - a surface temperature study (open access)

Characterization of fundamental catalytic properties of MoS2/WS2 nanotubes and nanoclusters for desulfurization catalysis - a surface temperature study

The prior project consisted of two main project lines. First, characterization of novel nanomaterials for hydrodesulfurization (HDS) applications. Second, studying more traditional model systems for HDS such as vapor-deposited silica-supported Mo and MoSx clusters. In the first subproject, we studied WS2 and MoS2 fullerene-like nanoparticles as well as WS2 nanotubes. Thiophene (C4H4S) was used as the probe molecule. Interestingly, metallic and sulfur-like adsorption sites could be identified on the silica-supported fullerene-particles system. Similar structures are seen for the traditional system (vapor-deposited clusters). Thus, this may be a kinetics fingerprint feature of modern HDS model systems. In addition, kinetics data allowed characterization of the different adsorption sites for thiophene on and inside WS2 nanotube bundles. The latter is a unique feature of nanotubes that has not been reported before for any inorganic nanotube system; however, examples are known for carbon nanotubes, including prior work of the PI. Although HDS has been studied for decades, utilizing nanotubes as nanosized HDS reactors has never been tried before, as far as we know. This is of interest from a fundamental perspective. Unfortunately, the HDS activity of the nanocatalysts at ultra-high vacuum (UHV) conditions was close to the detection limit of our techniques. Therefore, we …
Date: July 5, 2012
Creator: Burghaus, U.
Object Type: Report
System: The UNT Digital Library
Coexistence of the Alpha and Delta Phases in As-Cast Uranium-Rich U-Zr Alloys (open access)

Coexistence of the Alpha and Delta Phases in As-Cast Uranium-Rich U-Zr Alloys

None
Date: September 5, 2012
Creator: McKeown, J T; Irukuvarghula, S; Ahn, S; Wall, M; Hsiung, L L; McDeavitt, S et al.
Object Type: Article
System: The UNT Digital Library
COLLABORATIVE: FUSION SIMULATION PROGRAM (open access)

COLLABORATIVE: FUSION SIMULATION PROGRAM

New York University, Courant Institute of Mathematical Sciences, participated in the “Fusion Simulation Program (FSP) Planning Activities” [http://www.pppl.gov/fsp], with C.S. Chang as the institutional PI. FSP’s mission was to enable scientific discovery of important new plasma phenomena with associated understanding that emerges only upon integration. This requires developing a predictive integrated simulation capability for magnetically-confined fusion plasmas that are properly validated against experiments in regimes relevant for producing practical fusion energy. Specific institutional goal of the New York University was to participate in the planning of the edge integrated simulation, with emphasis on the usage of large scale HPCs, in connection with the SciDAC CPES project which the PI was leading. New York University successfully completed its mission by participating in the various planning activities, including the edge physics integration, the edge science drivers, and the mathematical verification. The activity resulted in the combined report that can be found in http://www.pppl.gov/fsp/Overview.html. Participation and presentations as part of this project are listed in a separation file.
Date: June 5, 2012
Creator: Chang, Choong Seock
Object Type: Report
System: The UNT Digital Library
Compressing Phasor Measurement Data (open access)

Compressing Phasor Measurement Data

None
Date: December 5, 2012
Creator: Top, P. & Breneman, J.
Object Type: Article
System: The UNT Digital Library
Conceptual Design - Polar Drive Ignition Campaign (open access)

Conceptual Design - Polar Drive Ignition Campaign

The Laboratory for Laser Energetics (LLE) at the University of Rochester is proposing a collaborative effort with Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratories (LANL), the Naval Research Laboratory (NRL), and General Atomics (GA) with the goal of developing a cryogenic polar drive (PD) ignition platform on the National Ignition Facility (NIF). The scope of this proposed project requires close discourse among theorists, experimentalists, and laser and system engineers. This document describes how this proposed project can be broken into a series of parallel independent activities that, if implemented, could deliver this goal in the 2017 timeframe. This Conceptual Design document is arranged into two sections: mission need and design requirements. Design requirements are divided into four subsystems: (1) A point design that details the necessary target specifications and laser pulse requirements; (2) The beam smoothing subsystem that describes the MultiFM 1D smoothing by spectral dispersion (SSD); (3) New optical elements that include continuous phase plates (CPP's) and distributed polarization rotators (DPR's); and (4) The cryogenic target handling and insertion subsystem, which includes the design, fabrication, testing, and deployment of a dedicated PD ignition target insertion cryostat (PD-ITIC). This document includes appendices covering: the primary criteria and functional …
Date: April 5, 2012
Creator: Hansen, R
Object Type: Report
System: The UNT Digital Library
DDT of Aluminum/Air Mixtures in a Tunnel (open access)

DDT of Aluminum/Air Mixtures in a Tunnel

None
Date: January 5, 2012
Creator: Balakrishnan, K; Kuhl, A L & Bell, J B
Object Type: Article
System: The UNT Digital Library
Design & Fabrication of a High-Voltage Photovoltaic Cell (open access)

Design & Fabrication of a High-Voltage Photovoltaic Cell

Silicon photovoltaic (PV) cells are alternative energy sources that are important in sustainable power generation. Currently, applications of PV cells are limited by the low output voltage and somewhat low efficiency of such devices. In light of this fact, this project investigates the possibility of fabricating high-voltage PV cells on float-zone silicon wafers having output voltages ranging from 50 V to 2000 V. Three designs with different geometries of diffusion layers were simulated and compared in terms of metal coverage, recombination, built-in potential, and conduction current density. One design was then chosen and optimized to be implemented in the final device design. The results of the simulation serve as a feasibility test for the design concept and provide supportive evidence of the effectiveness of silicon PV cells as high-voltage power supplies.
Date: September 5, 2012
Creator: Felder, Jennifer & /SLAC, /North Carolina State U.
Object Type: Report
System: The UNT Digital Library
Design of An 18 MW Beam Dump for 500 GeV Electron/Positron Beams at An ILC (open access)

Design of An 18 MW Beam Dump for 500 GeV Electron/Positron Beams at An ILC

This article presents a report on the progress made in designing 18 MW water based Beam Dumps for electrons or positrons for an International Linear Collider (ILC). Multi-dimensional technology issues have to be addressed for the successful design of the Beam Dump. They include calculations of power deposition by the high energy electron/positron beam bunch trains, computational fluid dynamic analysis of turbulent water flow, mechanical design, process flow analysis, hydrogen/oxygen recombiners, handling of radioactive 7Be and 3H, design of auxiliary equipment, provisions for accident scenarios, remote window exchanger, radiation shielding, etc. The progress made to date is summarized, the current status, and also the issues still to be addressed.
Date: July 5, 2012
Creator: Amann, John; /SLAC; Arnold, Ray; /SLAC; Seryi, Andrei; /SLAC et al.
Object Type: Article
System: The UNT Digital Library
Development of High Average Power Lasers for the Photon Collider (open access)

Development of High Average Power Lasers for the Photon Collider

The laser and optics system for the photon collider seeks to minimize the required laser power by using an optical stacking cavity to recirculate the laser light. An enhancement of between 300 to 400 is desired. In order to achieve this the laser pulses which drive the cavity must precisely match the phase of the pulse circulating within the cavity. We report on simulations of the performance of a stacking cavity to various variations of the drive laser in order to specify the required tolerances of the laser system.
Date: July 5, 2012
Creator: Gronberg, Jeff; /LLNL, Livermore; Stuart, Brent; /LLNL, Livermore; Seryi, Andrei & /SLAC
Object Type: Article
System: The UNT Digital Library
Discovery of Very High Energy Gamma Rays from PKS 1424+240 and Multiwavelength Constraints on its Redshift (open access)

Discovery of Very High Energy Gamma Rays from PKS 1424+240 and Multiwavelength Constraints on its Redshift

We report the first detection of very-high-energy (VHE) gamma-ray emission above 140GeV from PKS 1424+240, a BL Lac object with an unknown redshift. The photon spectrum above 140GeV measured by VERITAS is well described by a power law with a photon index of 3.8 {+-}0.5{sub stat} {+-} 0.3{sub syst} and a flux normalization at 200 GeV of (5.1 {+-} 0.9{sub stat} {+-} 0.5{sub syst}) x 10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}, where stat and syst denote the statistical and systematical uncertainty, respectively. The VHE flux is steady over the observation period between MJD 54881 and 55003 (2009 February 19 to June 21). Flux variability is also not observed in contemporaneous high energy observations with the Fermi Large Area Telescope (LAT). Contemporaneous X-ray and optical data were also obtained from the Swift XRT and MDM observatory, respectively. The broadband spectral energy distribution (SED) is well described by a one-zone synchrotron self-Compton (SSC) model favoring a redshift of less than 0.1. Using the photon index measured with Fermi in combination with recent extragalactic background light (EBL) absorption models it can be concluded from the VERITAS data that the redshift of PKS 1424+240 is less than 0.66.
Date: April 5, 2012
Creator: Acciari, V. A.; Aliu, E.; Arlen, T.; Aune, T.; Bautista, M.; Beilicke, M. et al.
Object Type: Report
System: The UNT Digital Library
Dynamic structure factor in warm dense beryllium (open access)

Dynamic structure factor in warm dense beryllium

None
Date: April 5, 2012
Creator: Glenzer, S H; Fortmann, C; Doeppner, T; Plagemann, K U; Sperling, P; Thiele, R et al.
Object Type: Article
System: The UNT Digital Library
Effect of SOFC Interconnect-Coating Interactions on Coating Properties and Performance (open access)

Effect of SOFC Interconnect-Coating Interactions on Coating Properties and Performance

The high operating temperature of solid oxide fuel cells (SOFCs) provides good fuel flexibility which expands potential applications, but also creates materials challenges. One such challenge is the interconnect material, which was the focus of this project. In particular, the objective of the project was to understand the interaction between the interconnect alloy and ceramic coatings which are needed to minimize chromium volatilization and the associated chromium poisoning of the SOFC cathode. This project focused on coatings based on manganese cobalt oxide spinel phases (Mn,Co)3O4, which have been shown to be effective as coatings for ferritic stainless steel alloys. Analysis of diffusion couples was used to develop a model to describe the interaction between (Mn,Co)3O4 and Cr2O3 in which a two-layer reaction zone is formed. Both layers form the spinel structure, but the concentration gradients at the interface appear like a two-phase boundary suggesting that a miscibility gap is present in the spinel solid solution. A high-chromium spinel layer forms in contact with Cr2O3 and grows by diffusion of manganese and cobalt from the coating material to the Cr2O3. The effect of coating composition, including the addition of dopants, was evaluated and indicated that the reaction rate could be decreased …
Date: September 5, 2012
Creator: Fergus, Jeffrey W.
Object Type: Report
System: The UNT Digital Library