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ATF2 Commissioning
ATF2 is a final-focus test beam line that aims to focus the low-emittance beam from the ATF damping ring to a beam size of about 37 nm, and at the same time to demonstrate nm beam stability, using numerous advanced beam diagnostics and feedback tools. The construction has been finished at the end of 2008 and the beam commissioning of ATF2 has started in December of 2008. ATF2 is constructed and commissioned by ATF international collaborations with strong US, Asian and European participation.
Date:
October 30, 2009
Creator:
Seryi, A.; Christian, G.; Parker, B.; Schulte, D.; Delahaye, J. -P.; Tomas, R. et al.
Object Type:
Article
System:
The UNT Digital Library
Aviation Safety: Information on the Safety Effects of Modifying the Age Standard for Commercial Pilots
Correspondence issued by the Government Accountability Office with an abstract that begins "The Fair Treatment for Experienced Pilots Act (the act) extended the federal age standard for pilots of large commercial aircraft from 60 to 65 years of age. The act also requires us to report--no later than 24 months after its enactment--on the effect, if any, of this change on aviation safety. This report responds to that requirement."
Date:
October 30, 2009
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Black Lung Benefits Program: Administrative and Structural Changes Could Improve Miners' Ability to Pursue Claims
A letter report issued by the Government Accountability Office with an abstract that begins "The Department of Labor (DOL) Black Lung Benefits Program provides medical and income assistance to coal miners who suffer total disability or death due to lung disease caused by coal dust. To provide insight into DOL's administration of the Black Lung Benefits Program, GAO is reporting on (1) how long it takes to process and resolve black lung benefits claims; (2) at what rate and for what reasons black lung claims and appeals are denied by DOL; and (3) what barriers, if any, confront miners or their survivors in pursuing their claims. GAO collected and analyzed black lung claims and appeals data and interviewed officials at relevant federal agencies, national organizations, and selected local organizations at two sites."
Date:
October 30, 2009
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Branching fractions and charge asymmetries in charmless hadronic decays at BABAR
We present measurements of branching fraction, polarization and charge asymmetry in charmless hadronic B decays with {eta}, {eta}{prime}, {omega}, and b{sub 1} in the final state. All the results use the final BABAR dataset.
Date:
October 30, 2009
Creator:
Biassoni, Pietro
Object Type:
Article
System:
The UNT Digital Library
Coal Combustion Residue: Status of EPA's Efforts to Regulate Disposal
Correspondence issued by the Government Accountability Office with an abstract that begins "On December 22, 2008, a breach in a surface impoundment (or storage pond) dike at the Tennessee Valley Authority (TVA) Kingston Fossil Plant in Tennessee resulted in the release of 5.4 million cubic yards of coal ash--also referred to as coal combustion residue (CCR)--into the nearby Emory River. The spill covered more than 300 acres and made 3 homes uninhabitable; it damaged 23 other homes, plus roads, rail lines, and utilities. TVA estimated the cleanup will cost between $933 million and $1.2 billion and take 2 to 3 years to complete. In light of the spill in Kingston, Congress asked us to identify: (1) the number of surface impoundments for storing CCR in the United States and their location; (2) problems, if any, with the storage of coal ash, and how those problems are being addressed; and (3) the type of federal oversight that exists for CCR and what, if any, issues need to be resolved. We briefed your staffs on October 1, 2009, and September 28, 2009, respectively, on the results of this work. This report summarizes and transmits that briefing. The full briefing is reprinted in …
Date:
October 30, 2009
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
A Concept of Plasma Wake Field Acceleration Linear Collider (PWFA-LC)
Plasma Wake-Field Acceleration (PWFA) has demonstrated acceleration gradients above 50 GeV/m. Simulations have shown drive/witness bunch configurations that yield small energy spreads in the accelerated witness bunch and high energy transfer efficiency from the drive bunch to the witness bunch, ranging from 30% for a Gaussian drive bunch to 95% for a shaped longitudinal profile. These results open the opportunity for a linear collider that could be compact, efficient and more cost effective that the present microwave technologies. A concept of a PWFA-based Linear Collider (PWFA-LC) has been developed and is described in this paper. The drive beam generation and distribution, requirements on the plasma cells, and optimization of the interaction region parameters are described in detail. The R&D steps needed for further development of the concept are also outlined.
Date:
October 30, 2009
Creator:
Seryi, Andrei; Hogan, Mark; Pei, Shilun; Raubenheimer, Tor; Tenenbaum, Peter; Katsouleas, Tom et al.
Object Type:
Article
System:
The UNT Digital Library
Connecting Reionization to the Local Universe
We present results of combined N-body and three-dimensional reionization calculations to determine the relationship between reionization history and local environment in a volume 1 Gcp h$sup -1$ across and a resolution of about 1 Mpc. We achieve this by applying three dimensional simulations of reionization, based on the extended Press-Schechter formalism, to the same initial conditions as the N-body simulations. We resolve about 2 X 10$sup 6$ halos of mass greater than ~ 10$sup 12$M at z = 0, and determine the relationship between halo mass and reionization epoch for galaxies and clusters. For our fiducial reionization model, in which reionization begins at z ~ 15 and ends by z ~ 6, we find a strong bias for cluster-size halos to be in the regions which reionized first, at redshifts 10 < z < 15. Consequently, material in clusters was reionized within relatively small regious, on the order of a few Mpc, implying that all clusters in our calculation were reionized by their own progenitors. Milky Way mass halos were on average reionized later and by larger regions, with a distribution most similar to the global one, indicating that low mass halos are nearly uncorrelated with reionization when only halo …
Date:
October 30, 2009
Creator:
Alvarez, Marcelo
Object Type:
Article
System:
The UNT Digital Library
Constraining Emission Models of Luminous Blazar Sources
Many luminous blazars which are associated with quasar-type active galactic nuclei display broad-band spectra characterized by a large luminosity ratio of their high-energy ({gamma}-ray) and low-energy (synchrotron) spectral components. This large ratio, reaching values up to 100, challenges the standard synchrotron self-Compton models by means of substantial departures from the minimum power condition. Luminous blazars have also typically very hard X-ray spectra, and those in turn seem to challenge hadronic scenarios for the high energy blazar emission. As shown in this paper, no such problems are faced by the models which involve Comptonization of radiation provided by a broad-line-region, or dusty molecular torus. The lack or weakness of bulk Compton and Klein-Nishina features indicated by the presently available data favors production of {gamma}-rays via up-scattering of infrared photons from hot dust. This implies that the blazar emission zone is located at parsec-scale distances from the nucleus, and as such is possibly associated with the extended, quasi-stationary reconfinement shocks formed in relativistic outflows. This scenario predicts characteristic timescales for flux changes in luminous blazars to be days/weeks, consistent with the variability patterns observed in such systems at infrared, optical and {gamma}-ray frequencies. We also propose that the parsec-scale blazar activity can …
Date:
October 30, 2009
Creator:
Sikora, Marek; Stawarz, Lukasz; Moderski, Rafal; Nalewajko, Krzysztof & Madejski, Greg
Object Type:
Article
System:
The UNT Digital Library
Construction and Performance of the BaBar DIRC
The new type of ring-imaging Cherenkov detector technology called DIRC (an acronym for Detection of Internally Reflected Cherenkov (Light)) has been used successfully for hadronic particle identification in the BABAR experiment at the B Factory (PEP-II) located at the SLAC National Accelerator Laboratory. This paper describes the R&D for and the construction of the DIRC radiator bars and the performance of the DIRC during more than eight years of B Factory operation.
Date:
October 30, 2009
Creator:
Schwiening, Jochen
Object Type:
Article
System:
The UNT Digital Library
The Controlled Synthesis of Metastable Oxides Utilizing Epitaxy and Epitaxial Stabilization
The research enabled by this DOE grant led to 13 publications in leading refereed journals including Physical Review Letters and Applied Physics Letters as well as feature articles in the Journal of the American Ceramic Society and Physik Journal (the German equivalent of Physics Today distributed to all members of the German Physical Society) on the controlled synthesis of metastable oxides utilizing epitaxy and epitaxial stabilization. In total our results fill over 100 pages of archived journals and are attached.
Date:
October 30, 2009
Creator:
Schlom, Dr. Darrell G.
Object Type:
Report
System:
The UNT Digital Library
Coupling Sorption to Soil Weathering During Reactive Transport: Impacts of Mineral Transformation and Sorbent Aging on Contaminant Speciation and Mobility
This project aimed for a predictive-mechanistic understanding of the coupling between mineral weathering and contaminant (Cs, Sr, I) transport/fate in caustic waste-impacted sediments. Based on our prior studies of model clay mineral systems, we postulated that contaminant uptake to Hanford sediments would reflect concurrent adsorption and co-precipitation effects. Our specific objectives were: (1) to assess the molecular-scale mechanisms responsible for time-dependent sequestration of contaminants (Cs, Sr and I) during penetration of waste-induced weathering fronts; (2) to determine the rate and extent of contaminant release from the sorbed state; (3) to develop a reactive transport model based on molecular mechanisms and macroscopic flow experiments [(1) and (2)] that simulates adsorption, aging, and desorption dynamics. Progress toward achieving each of these objectives is discussed below. We observed unique molecular mechanisms for sequestration of Sr, Cs and I during native silicate weathering in caustic waste. Product solids, which included poorly crystalline aluminosilicates and well-crystallized zeolites and feldspathoids, accumulate contaminant species during crystal growth.
Date:
October 30, 2009
Creator:
Chorover, J.; Mueller, K. T.; O'Day, P. A.; Serne, R. J. & Steefel, C. I.
Object Type:
Report
System:
The UNT Digital Library
Facility for Advanced Accelerator Experimental Tests at SLAC (FACET) Conceptual Design Report
This Conceptual Design Report (CDR) describes the design of FACET. It will be updated to stay current with the developing design of the facility. This CDR begins as the baseline conceptual design and will evolve into an 'as-built' manual for the completed facility. The Executive Summary, Chapter 1, gives an introduction to the FACET project and describes the salient features of its design. Chapter 2 gives an overview of FACET. It describes the general parameters of the machine and the basic approaches to implementation. The FACET project does not include the implementation of specific scientific experiments either for plasma wake-field acceleration for other applications. Nonetheless, enough work has been done to define potential experiments to assure that the facility can meet the requirements of the experimental community. Chapter 3, Scientific Case, describes the planned plasma wakefield and other experiments. Chapter 4, Technical Description of FACET, describes the parameters and design of all technical systems of FACET. FACET uses the first two thirds of the existing SLAC linac to accelerate the beam to about 20GeV, and compress it with the aid of two chicanes, located in Sector 10 and Sector 20. The Sector 20 area will include a focusing system, the …
Date:
October 30, 2009
Creator:
Amann, J. & Bane, K.
Object Type:
Report
System:
The UNT Digital Library
Federal Energy Management: Agencies Are Taking Steps to Meet High-Performance Federal Building Requirements, but Face Challenges
A letter report issued by the Government Accountability Office with an abstract that begins "The federal government is the nation's largest energy consumer. The Energy Independence and Security Act of 2007 (EISA) establishes high-performance federal building requirements that include reducing energy use and managing storm water runoff. The Department of Energy (DOE), General Services Administration (GSA), Office of Management and Budget (OMB), and Environmental Protection Agency (EPA) are implementing and, in turn, helping other agencies to implement EISA requirements. The American Recovery and Reinvestment Act of 2009 (Recovery Act) provides funding that some agencies can use to carry out EISA high-performance federal building requirements. This report, required by EISA, addresses (1) what implementing agencies are doing to direct and assist other agencies in meeting key EISA high-performance federal building requirements, (2) how implementing agencies are planning to use Recovery Act funds to meet key requirements, and (3) what challenges implementing and other agencies might face. To do this, GAO reviewed legal materials, guidance, draft energy data, and other documents and interviewed agency officials and stakeholders. DOE and GSA generally agreed with the report's findings and conclusions and provided written comments. OMB neither agreed nor disagreed with the report and provided …
Date:
October 30, 2009
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Final Report: Migration Mechanisms for Large-scale Parallel Applications
Process migration is the ability to transfer a process from one machine to another. It is a useful facility in distributed computing environments, especially as computing devices become more pervasive and Internet access becomes more ubiquitous. The potential benefits of process migration, among others, are fault resilience by migrating processes off of faulty hosts, data access locality by migrating processes closer to the data, better system response time by migrating processes closer to users, dynamic load balancing by migrating processes to less loaded hosts, and improved service availability and administration by migrating processes before host maintenance so that applications can continue to run with minimal downtime. Although process migration provides substantial potential benefits and many approaches have been considered, achieving transparent process migration functionality has been difficult in practice. To address this problem, our work has designed, implemented, and evaluated new and powerful transparent process checkpoint-restart and migration mechanisms for desktop, server, and parallel applications that operate across heterogeneous cluster and mobile computing environments. A key aspect of this work has been to introduce lightweight operating system virtualization to provide processes with private, virtual namespaces that decouple and isolate processes from dependencies on the host operating system instance. This decoupling …
Date:
October 30, 2009
Creator:
Nieh, Jason
Object Type:
Report
System:
The UNT Digital Library
Fire Grants: FEMA Has Met Most Requirements for Awarding Fire Grants, but Additional Actions Would Improve Its Grant Process
A letter report issued by the Government Accountability Office with an abstract that begins "The Department of Homeland Security, through the Federal Emergency Management Agency (FEMA), awards grants to fire departments and other organizations for equipment, staffing, and other needs. As of July 2009, FEMA had received about 25,000 and 22,000 applications for its fiscal years 2007 and 2008 fire grant programs, respectively, and had awarded more than 5,000 grants in both years. GAO was congressionally directed to review the application and award process for these grants. This report addresses the (1) extent to which FEMA has met statutory and program requirements for distributing the grant funds; (2) actions FEMA has taken to provide assistance to grant applicants and involve the fire service community in the grant process; and (3) extent to which FEMA has ensured that its grant process is accessible, clear, and consistent with requirements, including its grant guidance. GAO analyzed relevant laws and interviewed 36 randomly selected grant applicants to obtain their views, but the results are not generalizable."
Date:
October 30, 2009
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Free Electron Laser for Gamma-Gamma Collider at a Low-Energy Option of International Linear Collider
Different scenarios of a start-up with International Linear Collider (ILC) are under discussion at the moment in the framework of the Global Design Effort (GDE). One of them assumes construction of the ILC in stages from some minimum CM energy up to final target of 500 GeV CM energy. Gamma-gamma collider with CM energy of 180GeV is considered as a candidate for the first stage of the facility. In this report we present conceptual design of a free electron laser as a source of primary photons for the first stage of ILC.
Date:
October 30, 2009
Creator:
Saldin, Evgeny; Schneidmiller, Evgeny; Yurkov, Mikhail & Seryi, Andrei
Object Type:
Article
System:
The UNT Digital Library
Household Goods Moving Industry: Progress Has Been Made in Enforcement, but Increased Focus on Consumer Protection Is Needed
A letter report issued by the Government Accountability Office with an abstract that begins "Each year, the Federal Motor Carrier Safety Administration (FMCSA) within the Department of Transportation (DOT) receives about 3,000 consumer complaints regarding interstate moving companies: some involve egregious offenses, such as holding goods hostage. Over the years, Congress and GAO have raised concerns about the adequacy of FMCSA's oversight of the industry. As requested, GAO reviewed the (1) extent to which states have used authority in the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) to take federal enforcement action against interstate movers and challenges in using that authority; (2) extent and timeliness of FMCSA's progress in its consumer protection efforts; and (3) advantages and disadvantages of options for enhancing consumer protection in the industry. GAO analyzed applicable laws and regulations; interviewed government, moving industry, and consumer protection officials; surveyed state regulatory agencies and state attorneys general; and analyzed consumer protection models."
Date:
October 30, 2009
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Jordan: Background and U.S. Relations
This report provides an overview of Jordanian politics and current issues in U.S.-Jordanian relations. It provides a brief discussion of Jordan's government and economy and of its cooperation in promoting Arab-Israeli peace and other U.S. policy objectives in the Middle East.
Date:
October 30, 2009
Creator:
Sharp, Jeremy M.
Object Type:
Report
System:
The UNT Digital Library
Laser smoothing of sub-micron grooves in hydroxyl-rich fused silica
Nano- to micrometer-sized surface defects on UV-grade fused silica surfaces are known to be effectively smoothed through the use of high-temperature localized CO{sub 2} laser heating, thereby enhancing optical properties. However, the details of the mass transport and the effect of hydroxyl content on the laser smoothing of defective silica at submicron length scales is still not completely understood. In this study, we examine the morphological evolution of sub-micron, dry-etched periodic surface structures on type II and type III SiO{sub 2} substrates under 10.6 {micro}m CO{sub 2} laser irradiation using atomic force microscopy (AFM). In-situ thermal imaging was used to map the transient temperature field across the heated region, allowing assessment of the T-dependent mass transport mechanisms under different laser-heating conditions. Computational fluid dynamics simulations correlated well with experimental results, and showed that for large effective capillary numbers (N{sub c} > 2), surface diffusion is negligible and smoothing is dictated by capillary action, despite the relatively small spatial scales studied here. Extracted viscosity values over 1700-2000K were higher than the predicted bulk values, but were consistent with the surface depletion of OH groups, which was confirmed using confocal Raman microscopy.
Date:
October 30, 2009
Creator:
Shen, N; Matthews, M J; Fair, J E; Britten, J A; Nguyen, H T; Cooke, D et al.
Object Type:
Article
System:
The UNT Digital Library
LCLS Undulator Commissioning, Alignment, and Performance
The LCLS x-ray FEL has recently achieved its 1.5-Angstrom lasing and saturation goals upon first trial. This was achieved as a result of a thorough pre-beam checkout, both traditional and beam-based component alignment techniques, and high electron beam brightness. The x-ray FEL process demands very tight tolerances on the straightness of the electron beam trajectory (<5 {micro}m) through the LCLS undulator system. Tight, but less stringent tolerances of {approx}100 {micro}m rms were met for the transverse placement of the individual undulator segments with respect to the beam axis. The tolerances for electron beam straightness can only be met through a beam-based alignment (BBA) method, which is implemented using large electron energy variations and sub-micron resolution cavity beam position monitors (BPM), with precise conventional alignment used to set the starting conditions. Precision-fiducialization of components mounted on remotely adjustable girders, and special beam-finder wires (BFW) at each girder have been used to meet these challenging alignment tolerances. Longer-term girder movement due to ground motion and temperature changes are being monitored, continuously, by a unique stretched wire and hydrostatic level Alignment Diagnostics System (ADS).
Date:
October 30, 2009
Creator:
Nuhn, Heinz-Dieter
Object Type:
Article
System:
The UNT Digital Library
Measurement of Branching Fractions of B decays to K1(1270)pi and K1(1400)pi and Determination of the CKM angle alpha from B0 --> a1(1260) /- pi-/
We report measurements of the branching fractions of neutral and charged B meson decays to final states containing a K{sub 1}(1270) or K{sub 1}(1400) meson and a charged pion. The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, correspond to 454 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation. We measure the branching fractions {Beta}(B{sup 0} {yields} K{sub 1}(1270){sup +}{pi}{sup -} + K{sub 1}(1400){sup +}{pi}{sup -}) = 3.1{sub 0.7}{sup +0.8} x 10{sup -5} and {Beta}(B{sup +} {yields} K{sub 1}(1270){sup 0}{pi}{sup +} + K{sub 1}(1400){sup 0}{pi}{sup +}) = 2.9{sub -1.7}{sup +2.9} x 10{sup -5} (< 8.2 x 10{sup -5} at 90% confidence level), where the errors are statistical and systematic combined. The B{sup 0} decay mode is observed with a significance of 7.5{sigma}, while a significance of 3.2{sigma} is obtained for the B{sup +} decay mode. Based on these results, we estimate the weak phase {alpha} = (79 {+-} 7 {+-} 11){sup o} from the time dependent CP asymmetries in B{sup 0} {yields} a{sub 1}(1260){sup {+-}}{pi}{sup {-+}} decays.
Date:
October 30, 2009
Creator:
Aubert, B.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurements of the tau Mass and Mass Difference of the tau^+ and tau^- at BABAR
The authors present the result of a precision measurement of the mass of the {tau} lepton, M{sub {tau}}, based on 423 fb{sup -1} of data recorded at the {Upsilon}(4S) resonance with the BABAR detector. Using a pseudomass endpoint method, they determine the mass to be 1776.68 {+-} 0.12(stat) {+-} 0.41(syst) MeV. They also measure the mass difference between the {tau}{sup +} and {tau}{sup -}, and obtain (M{sub {tau}{sup +}} - M{sub {tau}{sup -}})/M{sub AVG}{sup {tau}} = (-3.4 {+-} 1.3(stat) {+-} 0.3(syst)) x 10{sup -4}, where M{sub AVG}{sup {tau}} is the average value of M{sub {tau}{sup +}} and M{sub {tau}{sup -}}.
Date:
October 30, 2009
Creator:
Aubert, B.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Object Type:
Article
System:
The UNT Digital Library
Nuclear Hydrogen Initiative, Results of the Phase II Testing of Sulfur-Iodine Integrated Lab Scale Experiments
International collaborative effort to construct a laboratory-scale Sulfur-Iodine process capable of producing 100-200 L/hr of hydrogen.
Date:
October 30, 2009
Creator:
Russ, Benjamin; Naranjo, G.; Moore, R.; Sweet, W.; Hele, M. & Pons, N.
Object Type:
Report
System:
The UNT Digital Library
Power Saving Optimization for Linear Collider Interaction Region Parameters
Optimization of Interaction Region parameters of a TeV energy scale linear collider has to take into account constraints defined by phenomena such as beam-beam focusing forces, beamstrahlung radiation, and hour-glass effect. With those constraints, achieving a desired luminosity of about 2E34 would require use of e{sup +}e{sup -} beams with about 10 MW average power. Application of the 'travelling focus' regime may allow the required beam power to be reduced by at least a factor of two, helping reduce the cost of the collider, while keeping the beamstrahlung energy loss reasonably low. The technique is illustrated for the 500 GeV CM parameters of the International Linear Collider. This technique may also in principle allow recycling the e{sup +}e{sup -} beams and/or recuperation of their energy.
Date:
October 30, 2009
Creator:
Seryi, Andrei
Object Type:
Article
System:
The UNT Digital Library