50 MW X-BAND RF SYSTEM FOR A PHOTOINJECTOR TEST STATION AT LLNL (open access)

50 MW X-BAND RF SYSTEM FOR A PHOTOINJECTOR TEST STATION AT LLNL

In support of X-band photoinjector development efforts at LLNL, a 50 MW test station is being constructed to investigate structure and photocathode optimization for future upgrades. A SLAC XL-4 klystron capable of generating 50 MW, 1.5 microsecond pulses will be the high power RF source for the system. Timing of the laser pulse on the photocathode with the applied RF field places very stringent requirements on phase jitter and drift. To achieve these requirements, the klystron will be powered by a state of the art, solid-state, high voltage modulator. The 50 MW will be divided between the photoinjector and a traveling wave accelerator section. A high power phase shifter is located between the photoinjector and accelerator section to adjust the phasing of the electron bunches with respect to the accelerating field. A variable attenuator is included on the input of the photoinjector. The distribution system including the various x-band components is being designed and constructed. In this paper, we will present the design, layout, and status of the RF system.
Date: March 11, 2011
Creator: Marsh, R A; Anderson, S G; Barty, C J; Beer, G K; Cross, R R; Ebbers, C A et al.
Object Type: Article
System: The UNT Digital Library
100-N Area Strontium-90 Treatability Demonstration Project: Phytoextraction Along the 100-N Columbia River Riparian Zone – Field Treatability Study (open access)

100-N Area Strontium-90 Treatability Demonstration Project: Phytoextraction Along the 100-N Columbia River Riparian Zone – Field Treatability Study

Strontium-90 (90Sr) is present both in the aquifer near the river and in the vadose and riparian zones of the river’s shore at 100-NR-2. Phytoextraction of 90Sr is being considered as a potential remediation system along the riparian zone of the Columbia River. Phytoextraction would employ coyote willow (Salix exigua). Past studies have shown that willow roots share uptake mechanisms for Sr with Ca, a plant macronutrient as well as no discrimination between Sr and 90Sr. Willow 90Sr concentration ratios [CR’s; (pCi 90Sr/g dry wt. of new growth tissue)/(pCi 90Sr/g soil porewater)] were consistently greater than 65 with three-quarters of the assimilated label partitioned into the above ground shoot. Insect herbivore experiments also demonstrated no significant potential for bioaccumulation or food chain transfer from their natural activities. The objectives of this field study were three-fold: (1) to demonstrate that a viable, “managed” plot of coyote willows can be established on the shoreline of the Columbia River that would survive the same microenvironment to be encountered at the 100-NR-2 shoreline; (2) to show through engineered barriers that large and small animal herbivores can be prevented from feeding on these plants; and (3) to show that once established, the plants will provide …
Date: January 11, 2010
Creator: Fellows, Robert J.; Fruchter, Jonathan S.; Driver, Crystal J. & Ainsworth, Calvin C.
Object Type: Report
System: The UNT Digital Library
T-1025 IU SciBath-768 detector tests in MI-12 (open access)

T-1025 IU SciBath-768 detector tests in MI-12

This is a memorandum of understanding between the Fermi National Accelerator Laboratory (Fermilab) and the experimenters of Department of Physics and Center for Exploration of Energy and Matter, Indiana University, who have committed to participate in detector tests to be carried out during the 2012 Fermilab Neutrino program. The memorandum is intended solely for the purpose of recording expectations for budget estimates and work allocations for Fermilab, the funding agencies and the participating institutions. it reflects an arrangement that currently is satisfactory to the parties; however, it is recognized and anticipated that changing circumstances of the evolving research program will necessitate revisions. The parties agree to modify this memorandum to reflect such required adjustments. Actual contractual obligations will be set forth in separate documents. The experimenters propsoe to test their prototype 'SciBat-768' detector in the MI-12 building for 3 months (February-April) in Spring 2012. The major goal of this effort is to measure or limit the flux of beam-induced neutrons in a far-off-axis (> 45{sup o}) location of the Booster Neutrino Beamline (BNB). This flux is of interest for a proposed coherent neutral-current neutrino-argon elastic scattering experiment. A second goal is to collect more test data for the SciBath-768 to …
Date: February 11, 2012
Creator: Tayloe, Rex; Cooper, R.; Garrison, L.; Thornton, T.; Rebenitsch, L.; DeJongh, Fritz et al.
Object Type: Report
System: The UNT Digital Library
2010 IRON-SULFUR ENZYMES GORDON RESEARCH CONFERENCE, JUNE 6-11, 2010 (open access)

2010 IRON-SULFUR ENZYMES GORDON RESEARCH CONFERENCE, JUNE 6-11, 2010

Iron-sulfur (FeS) centers are essential for biology and inspirational in chemistry. These protein cofactors are broadly defined as active sites in which Fe is coordinated by S-donor ligands, often in combination with extra non-protein components, for example, additional metal atoms such as Mo and Ni, and soft ligands such as CN{sup -} and CO. Iron-sulfur centers are inherently air sensitive: they are found in essentially all organisms and it is possible that they were integral components of the earliest forms of life, well before oxygen (O{sub 2}) appeared. Proteins containing FeS cofactors perform a variety of biological functions ranging across electron transfer, acid-base catalysis, and sensing where they are agents for cell regulation through transcription (DNA) or translation (RNA). They are redox catalysts for radical-based reactions and the activation of H{sub 2}, N{sub 2} and CO{sub 2}, processes that offer scientific and economic challenges for industry. Iron-sulfur centers provide the focus for fundamental investigations of chemical bonding, spectroscopy and paramagnetism, and their functions have numerous implications for health and medicine and applications for technology, including renewable energy. The 2010 Iron-Sulfur Enzymes GRC will bring together researchers from different disciplines for in-depth discussions and presentations of the latest developments. There will …
Date: June 11, 2010
Creator: Gray, Nancy Ryan
Object Type: Article
System: The UNT Digital Library
2010 MULTIPHOTON PROCESSES GORDON RESEARCH CONFERENCE, JUNE 6-11, 2010, TILTON, NH (open access)

2010 MULTIPHOTON PROCESSES GORDON RESEARCH CONFERENCE, JUNE 6-11, 2010, TILTON, NH

The Gordon Research Conference on Multiphoton Processes will be held for the 15th time in 2010. The meeting continues to evolve as it embraces both the rapid technological and intellectual growth in the field as well as the multi-disciplinary expertise of the participants. This time the sessions will focus on: (1) Ultrafast coherent control; (2) Free-electron laser experiments and theory; (3) Generation of harmonics and attosecond pulses; (4) Ultrafast imaging; (5) Applications of very high intensity laser fields; (6) Strong-field processes in molecules and solids; (7) Attosecond science; and (8) Controlling light. The scientific program will blur traditional disciplinary boundaries as the presenters and discussion leaders involve chemists, physicists, and optical engineers, representing both experiment and theory. The broad range of expertise and different perspectives of attendees should provide a stimulating and unique environment for solving problems and developing new ideas in this rapidly evolving field.
Date: June 11, 2010
Creator: Gaarde, Mette
Object Type: Article
System: The UNT Digital Library
2011 Chemical Reactions at Surfaces Gordon Research Conference (open access)

2011 Chemical Reactions at Surfaces Gordon Research Conference

The Gordon Research Conference on Chemical Reactions at Surfaces is dedicated to promoting and advancing the fundamental science of interfacial chemistry and physics by providing surface scientists with the foremost venue for presentation and discussion of research occurring at the frontiers of their fields.
Date: February 11, 2011
Creator: Stair, Peter
Object Type: Article
System: The UNT Digital Library
2011 Community Earth System Model (CESM) Tutorial, August 1-5, 2011 (open access)

2011 Community Earth System Model (CESM) Tutorial, August 1-5, 2011

In fiscal year 2011, the Community Earth System Model (CESM) tutorial was taught at NCAR from 1-5 August 2011. This project hosted 79 full participants (1 accepted participant from China couldn't get a visa) selected from 180 applications. The tutorial was advertised through emails to CESM mailing lists. NCAR staff and long-term visitors (who were not eligible to attend) were also invited to 'audit' the climate and practical lectures and to work on the practical sessions on their own. 15 NCAR staff and long-term visitors took advantage of this opportunity. The majority of the students were graduate students, but several post-docs, faculty, and other research scientists also attended. Additionally, many people are using the on-line lessons and practical sessions. As of August 18, 2011, 407 people had registered to access and use the tutorial from 33 countries all over the world, but a majority from US universities. In fiscal year 2011, the Climate and Global Dynamics Division Information Systems Group (CGD/ISG) built and operated a temporary computer laboratory in a meeting room. This project was made possible through funding from the National Science Foundation Directorate of Geosciences, and the Department of Energy Office of Science.
Date: October 11, 2013
Creator: Hurrell, James W.
Object Type: Article
System: The UNT Digital Library
2011 Computation Directorate Annual Report (open access)

2011 Computation Directorate Annual Report

From its founding in 1952 until today, Lawrence Livermore National Laboratory (LLNL) has made significant strategic investments to develop high performance computing (HPC) and its application to national security and basic science. Now, 60 years later, the Computation Directorate and its myriad resources and capabilities have become a key enabler for LLNL programs and an integral part of the effort to support our nation's nuclear deterrent and, more broadly, national security. In addition, the technological innovation HPC makes possible is seen as vital to the nation's economic vitality. LLNL, along with other national laboratories, is working to make supercomputing capabilities and expertise available to industry to boost the nation's global competitiveness. LLNL is on the brink of an exciting milestone with the 2012 deployment of Sequoia, the National Nuclear Security Administration's (NNSA's) 20-petaFLOP/s resource that will apply uncertainty quantification to weapons science. Sequoia will bring LLNL's total computing power to more than 23 petaFLOP/s-all brought to bear on basic science and national security needs. The computing systems at LLNL provide game-changing capabilities. Sequoia and other next-generation platforms will enable predictive simulation in the coming decade and leverage industry trends, such as massively parallel and multicore processors, to run petascale applications. …
Date: April 11, 2012
Creator: Crawford, D. L.
Object Type: Report
System: The UNT Digital Library
22X mask cleaning effects on EUV lithography process and lifetime (open access)

22X mask cleaning effects on EUV lithography process and lifetime

For this paper, we evaluated the impact of repetitive cleans on a photomask that was fabricated and patterned for extreme ultraviolet lithography exposure. The lithographic performance of the cleaned mask, in terms of process window and line edge roughness, was monitored with the SEMATECH Berkeley micro-exposure tool (MET). Each process measurement of the cleaned mask was compared to a reference mask with the same mask architecture. Both masks were imaged on the same day in order to eliminate any process-related measurement uncertainties. The cleaned mask was periodically monitored with atomic force microscopy (AFM) measurements and pattern widths were monitored using scanning electron microscopy (SEM). In addition, reflectivity changes were also tracked with the aid of witness plate measurements. At the conclusion of this study, the mask under evaluation was cleaned 22 times; with none of the evaluation techniques showing any significant degradation in performance.
Date: March 11, 2011
Creator: George, Simi A.; Chen, Robert J.; Baclea-an, Lorie Mae & Naulleau, Patrick P.
Object Type: Article
System: The UNT Digital Library
Ab Initio No-Core Shell Model (open access)

Ab Initio No-Core Shell Model

A long-standing goal of nuclear theory is to determine the properties of atomic nuclei based on the fundamental interactions among the protons and neutrons (i.e., nucleons). By adopting nucleon-nucleon (NN), three-nucleon (NNN) and higher-nucleon interactions determined from either meson-exchange theory or QCD, with couplings fixed by few-body systems, we preserve the predictive power of nuclear theory. This foundation enables tests of nature's fundamental symmetries and offers new vistas for the full range of complex nuclear phenomena. Basic questions that drive our quest for a microscopic predictive theory of nuclear phenomena include: (1) What controls nuclear saturation; (2) How the nuclear shell model emerges from the underlying theory; (3) What are the properties of nuclei with extreme neutron/proton ratios; (4) Can we predict useful cross sections that cannot be measured; (5) Can nuclei provide precision tests of the fundamental laws of nature; and (6) Under what conditions do we need QCD to describe nuclear structure, among others. Along with other ab initio nuclear theory groups, we have pursued these questions with meson-theoretical NN interactions, such as CD-Bonn and Argonne V18, that were tuned to provide high-quality descriptions of the NN scattering phase shifts and deuteron properties. We then add meson-theoretic NNN …
Date: April 11, 2011
Creator: Barrett, B R; Navratil, P & Vary, J P
Object Type: Article
System: The UNT Digital Library
Absence of Debye Sheaths Due to Secondary Electron Emission (open access)

Absence of Debye Sheaths Due to Secondary Electron Emission

A bounded plasma where the hot electrons impacting the walls produce more than one secondary on average is studied via particle-in-cell simulation. It is found that no classical Debye sheath or space-charge limited sheath exists. Ions are not drawn to the walls and electrons are not repelled. Hence the unconfined plasma electrons travel unobstructed to the walls, causing extreme particle and energy fluxes. Each wall has a positive charge, forming a small potential barrier or "inverse sheath" that pulls some secondaries back to the wall to maintain the zero current condition.
Date: May 11, 2012
Creator: Campanell, M. D.; Khabrov, A. & Kaganovich, I. D.
Object Type: Report
System: The UNT Digital Library
Absorber height effects on SWA restrictions and 'Shadow' LER (open access)

Absorber height effects on SWA restrictions and 'Shadow' LER

None
Date: March 11, 2011
Creator: McClinton, Brittany M.; Naulleau, Patrick P. & Wallow, Thomas
Object Type: Article
System: The UNT Digital Library
Accelerators for Intensity Frontier Research (open access)

Accelerators for Intensity Frontier Research

In 2008, the Particle Physics Project Prioritization Panel identified three frontiers for research in high energy physics, the Energy Frontier, the Intensity Frontier, and the Cosmic Frontier. In this paper, I will describe how Fermilab is configuring and upgrading the accelerator complex, prior to the development of Project X, in support of the Intensity Frontier.
Date: May 11, 2012
Creator: Derwent, Paul
Object Type: Article
System: The UNT Digital Library
Advanced Combustion (open access)

Advanced Combustion

The activity reported in this presentation is to provide the mechanical and physical property information needed to allow rational design, development and/or choice of alloys, manufacturing approaches, and environmental exposure and component life models to enable oxy-fuel combustion boilers to operate at Ultra-Supercritical (up to 650{degrees}C & between 22-30 MPa) and/or Advanced Ultra-Supercritical conditions (760{degrees}C & 35 MPa).
Date: March 11, 2013
Creator: Holcomb, Gordon R.
Object Type: Article
System: The UNT Digital Library
Advanced divertor configurations with large flux expansion. (open access)

Advanced divertor configurations with large flux expansion.

None
Date: June 11, 2012
Creator: et. al, V
Object Type: Article
System: The UNT Digital Library
Advanced High-Speed Framing Camera Development for Fast, Visible Imaging Experiments (open access)

Advanced High-Speed Framing Camera Development for Fast, Visible Imaging Experiments

The advances in high-voltage switching developed in this project allow a camera user to rapidly vary the number of output frames from 1 to 25. A high-voltage, variable-amplitude pulse train shifts the deflection location to the new frame location during the interlude between frames, making multiple frame counts and locations possible. The final deflection circuit deflects to five different frame positions per axis, including the center position, making for a total of 25 frames. To create the preset voltages, electronically adjustable {+-}500 V power supplies were chosen. Digital-to-analog converters provide digital control of the supplies. The power supplies are clamped to {+-}400 V so as not to exceed the voltage ratings of the transistors. A field-programmable gated array (FPGA) receives the trigger signal and calculates the combination of plate voltages for each frame. The interframe time and number of frames are specified by the user, but are limited by the camera electronics. The variable-frame circuit shifts the plate voltages of the first frame to those of the second frame during the user-specified interframe time. Designed around an electrostatic image tube, a framing camera images the light present during each frame (at the photocathode) onto the tube’s phosphor. The phosphor persistence …
Date: May 11, 2011
Creator: Amy Lewis, Stuart Baker, Brian Cox, Abel Diaz, David Glass, Matthew Martin
Object Type: Article
System: The UNT Digital Library
Advanced Simulation and Computing Fiscal Year 14 Implementation Plan, Rev. 0.5 (open access)

Advanced Simulation and Computing Fiscal Year 14 Implementation Plan, Rev. 0.5

None
Date: September 11, 2013
Creator: Meisner, R.; McCoy, M.; Archer, B. & Matzen, M.
Object Type: Report
System: The UNT Digital Library
Advanced Simulation and Computing FY13 Implementation Plan, Rev. 0.5 (open access)

Advanced Simulation and Computing FY13 Implementation Plan, Rev. 0.5

None
Date: September 11, 2012
Creator: Meisner, R.; McCoy, M.; Archer, B. & Cieslak, W.
Object Type: Report
System: The UNT Digital Library
Affordable Hydrogen Fuel Cell Vehicles (open access)

Affordable Hydrogen Fuel Cell Vehicles

Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program for hydrogen fuel cell vehicles (project title "Quaternary Phosphonium Based Hydroxide Exchange Membranes") including critical needs, innovation and advantages, impacts, and contact information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 11, 2012
Creator: Unviersity of Delaware
Object Type: Text
System: The UNT Digital Library
AGN Clustering in the Local Universe: An Unbiased Picture from Swift-BAT (open access)

AGN Clustering in the Local Universe: An Unbiased Picture from Swift-BAT

We present the clustering measurement of hard X-ray selected AGN in the local Universe. We used a sample of 199 sources spectroscopically confirmed detected by Swift-BAT in its 15-55 keV all-sky survey. We measured the real space projected auto-correlation function and detected a signal significant on projected scales lower than 200 Mpc/h. We measured a correlation length of r{sub 0} = 5.56{sup +0.49}{sub -0.43} Mpc/h and a slope {gamma} = 1.64{sup -0.08}{sub -0.07}. We also measured the auto-correlation function of Tyep I and Type II AGN and found higher correlation length for Type I AGN. We have a marginal evidence of luminosity dependent clustering of AGN, as we detected a larger correlation length of luminous AGN than that of low luminosity sources. The corresponding typical host DM halo masses of Swift-BAT are {approx} log(M{sub DMH) {approx} 12-14 h{sup -1}M/M{sub {circle_dot}} which is the typical mass of a galaxy group. We estimated that the local AGN population has a typical lifetime {tau}{sub AGN} {approx}0.7 Gyr, it is powered by SMBH with mass M{sub BH} {approx}1-10x10{sup 8} M{sub {circle_dot}} and accreting with very low efficiency, log({epsilon}){approx}-2.0>. We also conclude that local AGN galaxies are typically red-massive galaxies with stellar mass of the …
Date: August 11, 2011
Creator: Cappelluti, N.; /Garching, Max Planck Inst., MPE; Ajello, M.; /SLAC /KIPAC, Menlo Park; Burlon, D.; /Garching, Max Planck Inst., MPE et al.
Object Type: Article
System: The UNT Digital Library
AGN Unification at z ~ 1: u - R Colors and Gradients in X-ray AGN Hosts (open access)

AGN Unification at z ~ 1: u - R Colors and Gradients in X-ray AGN Hosts

None
Date: July 11, 2011
Creator: Ammons, S. M.; Rosario, D.; Koo, D.; Dutton, A.; Melbourne, J.; Max, C. et al.
Object Type: Article
System: The UNT Digital Library
Air Dispersion Modeling of Radioactive Releases During Proposed PFP Complex Demolition Activities (open access)

Air Dispersion Modeling of Radioactive Releases During Proposed PFP Complex Demolition Activities

This report is part of the planning process for the demolition of the 234-5Z, 236-Z, 242-Z, and 291-Z-1 structures at the Plutonium Finishing Plant (PFP) on the Hanford Site. Pacific Northwest National Laboratory (PNNL) supports the U.S. Department of Energy (DOE) and the CH2M HILL Plateau Remediation Company (CHPRC) demolition planning effort by making engineering estimates of potential releases for various potential demolition alternatives. This report documents an analysis considering open-air demolition using standard techniques. It does not document any decisions about the decommissioning approaches; it is expected that this report will be revisited as the final details of the demolition are developed.
Date: January 11, 2011
Creator: Napier, Bruce A.; Droppo, James G. & Rishel, Jeremy P.
Object Type: Report
System: The UNT Digital Library
Airborne Wind Turbine (open access)

Airborne Wind Turbine

Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program for more efficient and cheaper wind energy (project title "Airborne Wind Turbine") including critical needs, innovation and advantages, impacts, and contact information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 11, 2012
Creator: Makani Power Inc.
Object Type: Text
System: The UNT Digital Library
ALLOYING-DRIVEN PHASE STABILITY IN GROUP-VB TRANSITION METALS UNDER COMPRESSION (open access)

ALLOYING-DRIVEN PHASE STABILITY IN GROUP-VB TRANSITION METALS UNDER COMPRESSION

The change in phase stability of Group-VB (V, Nb, and Ta) transition metals due to pressure and alloying is explored by means of first-principles electronic-structure calculations. It is shown that under compression stabilization or destabilization of the ground-state body-centered cubic (bcc) phase of the metal is mainly dictated by the band-structure energy that correlates well with the position of the Kohn anomaly in the transverse acoustic phonon mode. The predicted position of the Kohn anomaly in V, Nb, and Ta is found to be in a good agreement with data from the inelastic x-ray or neutron scattering measurements. In the case of alloying the change in phase stability is defined by the interplay between the band-structure and Madelung energies. We show that band-structure effects determine phase stability when a particular Group-VB metal is alloyed with its nearest neighbors within the same d-transition series: the neighbor with less and more d electrons destabilize and stabilize the bcc phase, respectively. When V is alloyed with neighbors of a higher (4d- or 5d-) transition series, both electrostatic Madelung and band-structure energies stabilize the body-centered-cubic phase. The opposite effect (destabilization) happens when Nb or Ta is alloyed with neighbors of the 3d-transition series.
Date: April 11, 2011
Creator: Landa, A & Soderlind, P
Object Type: Article
System: The UNT Digital Library