LINAC DESIGN FOR AN ARRAY OF SOFT X-RAY FREE ELECTRON LASERS (open access)

LINAC DESIGN FOR AN ARRAY OF SOFT X-RAY FREE ELECTRON LASERS

The design of the linac delivering electron bunches into ten independent soft x-ray free electron lasers (FELs) producing light at 1 nm and longer wavelengths is presented. The bunch repetition rate in the linac is 1 MHz and 100 kHz in each of ten FEL beam lines. Various issues regarding machine layout and lattice, bunch compression, collimation, and the beam switch yard are discussed. Particular attention is given to collective effects. A demanding goal is to preserve both a low beam slice emittance and low slice energy spread during acceleration, bunch compression and distribution of the electron bunches into the array of FEL beamlines. Detailed studies of the effect of the electron beam microbunching caused by longitudinal space-charge forces and coherent synchrotron radiation (CSR) have been carried out and their results are presented.
Date: September 22, 2008
Creator: Zholents, Alexander A.; Kur, E.; Penn, G.; Qiang, Ji; Venturini, M. & Wells, R. P.
Object Type: Article
System: The UNT Digital Library
Model-Independent Jets plus Missing Energy Searches (open access)

Model-Independent Jets plus Missing Energy Searches

We present a proposal for performing model-independent jets plus missing energy searches. Currently, these searches are optimized for mSUGRA and are consequently not sensitive to all kinematically-accessible regions of parameter space. We show that the reach of these searches can be broadened by setting limits on the differential cross section as a function of the total visible energy and the missing energy. These measurements only require knowledge of the relevant Standard Model backgrounds and can be subsequently used to limit any theoretical model of new physics. We apply this approach to an example where gluinos are pair-produced and decay to the LSP through a single-step cascade, and show how sensitivity to different gluino masses is altered by the presence of the decay chain. The analysis is closely based upon the current searches done at the Tevatron and our proposal requires only small modifications to the existing techniques. We find that within the MSSM, the gluino can be as light as 125 GeV. The same techniques are applicable to jets and missing energy searches at the Large Hadron Collider.
Date: September 22, 2008
Creator: Alwall, Johan; Le, My-Phuong; Lisanti, Mariangela & Wacker, Jay G.
Object Type: Article
System: The UNT Digital Library
805 MHz Beta = 0.47 Elliptical Accelerating Structure R & D (open access)

805 MHz Beta = 0.47 Elliptical Accelerating Structure R & D

A 6-cell 805 MHz superconducting cavity for acceleration in the velocity range of about 0.4 to 0.53 times the speed of light was designed. After single-cell prototyping, three 6-cell niobium cavities were fabricated. In vertical RF tests of the 6-cell cavities, the measured quality factors (Q{sub 0}) were between 7 {center_dot} 10{sup 9} and 1.4 {center_dot} 10{sup 10} at the design field (accelerating gradient of 8 to 10 MV/m). A rectangular cryomodule was designed to house 4 cavities per cryomodule. The 4-cavity cryomodule could be used for acceleration of ions in a linear accelerator, with focusing elements between the cryomodules. A prototype cryomodule was fabricated to test 2 cavities under realistic operating conditions. Two of the 6-cell cavities were equipped with helium tanks, tuners, and input coupler and installed into the cryomodule. The prototype cryomodule was used to verify alignment, electromagnetic performance, frequency tuning, cryogenic performance, low-level RF control, and control of microphonics.
Date: September 22, 2008
Creator: Bricker, S.; Compton, C.; Hartung, W.; Johnson, M.; Marti, F.; Popierlarski, J. et al.
Object Type: Report
System: The UNT Digital Library
Modeling Growth of Au-Cu Nanocrystalliine Coatings (open access)

Modeling Growth of Au-Cu Nanocrystalliine Coatings

The electrodeposition process parameters of current density, pulse duration, and cell potential affect both the structure and composition of the foils. The mechanism for nucleation and growth as determined from current transients yield relationships for nucleus density and nucleation rate. To develop an understanding of the role of the process parameters on grain size--as a design structural parameter to control strength, for example, a formulation is presented to model the affects of the deposition energetics on grain size and morphology. An activation energy for the deposition process is modeled that reveals different growth mechanisms, wherein nucleation and diffusion effects are each dominant as dependent upon pulse duration. A diffusion coefficient common for each of the pulsed growth modes demarcates an observed transition in growth from smooth to rough surfaces. Empirical relationships are developed that relate the parameters of the deposition process to the morphology and grain size at the nanoscale. Regimes for nanocrystalline growth include a short and long pulse mode, each with distinct activation energies. The long pulse has the additional contribution of bulk-like diffusion whereas the short pulse is limited to surface diffusion and nucleation. For either pulse condition, a transition from a rough (or nodular) growth to …
Date: September 22, 2005
Creator: Jankowski, Alan Frederic
Object Type: Article
System: The UNT Digital Library
Silicon-Germanium Films Deposited by Low Frequency PE CVD: Effect of H2 and Ar Dilution (open access)

Silicon-Germanium Films Deposited by Low Frequency PE CVD: Effect of H2 and Ar Dilution

We have studied structure and electrical properties of Si{sub 1-Y}Ge{sub Y}:H films deposited by low frequency PE CVD over the entire composition range from Y=0 to Y=1. The deposition rate of the films and their structural and electrical properties were measured for various ratios of the germane/silane feed gases and with and without dilution by Ar and by H{sub 2}. Structure and composition was studied by Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS) and Fourier transform infrared (FTIR) spectroscopy. Surface morphology was characterized by atomic force microscopy (AFM). We found: (1) The deposition rate increased with Y maximizing at Y=1 without dilution. (2) The relative rate of Ge and Si incorporation is affected by dilution. (3) Hydrogen preferentially bonds to silicon. (4) Hydrogen content decreases for increasing Y. In addition, optical measurements showed that as Y goes for 0 to 1, the Fermi level moves from mid gap to the conduction band edge, i.e. the films become more n-type. No correlation was found between the pre-exponential and the activation energy of conductivity. The behavior of the conductivity {gamma}-factor suggests a local minimum in the density of states at E {approx} 0.33 eV for the films grown with or …
Date: September 22, 2005
Creator: Kosarev, A; Torres, A; Hernandez, Y; Ambrosio, R; Zuniga, C; Felter, T E et al.
Object Type: Article
System: The UNT Digital Library
Mu B-Driven Electroweak Symmetry Breaking (open access)

Mu B-Driven Electroweak Symmetry Breaking

None
Date: September 22, 2005
Creator: Nomura, Yasunori; Poland, David & Tweedie, Brock
Object Type: Article
System: The UNT Digital Library
A comparison of model short-range forecasts and the ARM Microbase data (open access)

A comparison of model short-range forecasts and the ARM Microbase data

For the fourth quarter ARM metric we will make use of new liquid water data that has become available, and called the 'Microbase' value added product (referred to as OBS, within the text) at three sites: the North Slope of Alaska (NSA), Tropical West Pacific (TWP) and the Southern Great Plains (SGP) and compare these observations to model forecast data. Two time periods will be analyzed March 2000 for the SGP and October 2004 for both TWP and NSA. The Microbase data have been averaged to 35 pressure levels (e.g., from 1000hPa to 100hPa at 25hPa increments) and time averaged to 3hourly data for direct comparison to our model output.
Date: September 22, 2006
Creator: Hnilo, J J
Object Type: Report
System: The UNT Digital Library
Final Technical Report Steam Cycle Washer for Unbleached Pulp (open access)

Final Technical Report Steam Cycle Washer for Unbleached Pulp

Project Abstract for “Steam Cycle Washer for Unbleached Pulp” When completed, the patented SC Washer will provide an innovative, energy efficient demonstration project to wash unbleached pulp using a pressure vessel charged with steam. The Port Townsend Paper Corporation’s pulp mill in Port Townsend, WA was initially selected as the host site for conducting the demonstration of the SCW. Due to 2006 and 2007 delays in the project caused by issues with 21st Century Pulp & Paper, the developer of the SCW, and the 2007 bankruptcy proceedings and subsequent restructuring at Port Townsend Paper, the mill can no longer serve as a host site. An alternate host site is now being sought to complete the commercial demonstration of the Steam Cycle Washer for Unbleached Pulp. Additionally, estimated costs to complete the project have more than doubled since the initial estimates for the project were completed in 2002. Additional grant funding from DOE was sought and in July, 2008 the additional DOE funds were procured under a new DOE award, DE-PS36-08GO98014 issued to INL. Once the new host site is secured the completion of the project will begin under the management of INL. Future progress reports and milestone tracking will be …
Date: September 22, 2008
Creator: Starkey, Yvonne; Salminen, Reijo & Karlsnes, Andy
Object Type: Report
System: The UNT Digital Library
Enhancement of T1 and T2 relaxation by paramagnetic silica-coated nanocrystals (open access)

Enhancement of T1 and T2 relaxation by paramagnetic silica-coated nanocrystals

None
Date: September 22, 2006
Creator: Gerion, D; Herberg, J; Gjersing, E; Ramon, E; Maxwell, R; Gray, J W et al.
Object Type: Article
System: The UNT Digital Library
2007 GRC on Cellulases and Cellulosomes (July 29-August 3, 2007) (open access)

2007 GRC on Cellulases and Cellulosomes (July 29-August 3, 2007)

Cellulose, a key component of the plant cell wall, comprises the most abundant source of organic carbon on the planet and its microbial degradation is of considerable biological and industrial importance. Indeed, the microbial degradation of cellulose and other plant structural polysaccharides is critical to the maintenance of the carbon cycle in terrestrial and marine microbial ecosystems, host invasion by several phytopathogens, and herbivore nutrition. While the enzymes that attack cellulose are already widely used in several biotechnology-based industries, the major future application of these biocatalysts is the conversion of plant biomass into bio-ethanol and other forms of energy. In that context, the 2007 Conference will present the latest breakthroughs in our understanding of the enzymology, structural biology and (meta)genomics underpinning the conversion of plant structural polysaccharides into fermentable sugars, both in natural and engineered processes. There is also an increased emphasis on the roles of other carbohydrate active enzymes in plant biomass conversion. The themes for the scientific sessions include: (1) crystallographic and biochemical analyses of enzyme structure and function; (2) molecular mechanisms underpinning enzyme catalysis, processivity and specificity; (3) functional and comparative analyses of carbohydrate binding modules and enzyme-substrate interactions; (4) directed evolution for the development of catalytically …
Date: September 22, 2008
Creator: Gray, Mark Morrison Nancy Ryan
Object Type: Article
System: The UNT Digital Library
THE EFFECT OF INTERSTITIAL N ON GRAIN BOUNDARY COHESIVE STRENGTH IN Fe (open access)

THE EFFECT OF INTERSTITIAL N ON GRAIN BOUNDARY COHESIVE STRENGTH IN Fe

Increased nitrogen levels have been correlated with decreased ductility and elevated ductile-to-brittle transition temperature in pressure vessel steels [1]. However, the exact role played by nitrogen in the embrittlement of steels remains unclear. Miller and Burke have reported atom probe ion microscopy findings from neutron-irradiated low-alloy pressure vessel steel showing the presence of a 1 to 2 ruonolayer thick film of Mo, N, and C at prior austenitic grain boundaries (GB's) [2], suggesting a role for nitrogen as an intergranular embrittler. It is of interest for the development of mitigation strategies whether nitrogen must combine with other impurities to form nitride precipitates in order to exert an embrittling effect. Briant et al [1] have associated the embrittling effect of N in steels exclusively with intergranular nitride formation. This association suggests that high nitrogen levels may be acceptable if nitride precipitation at grain boundaries is suppressed. To address whether precipitate formation is indeed essential to the N embrittlement process in pressure vessel steel, a computational study was undertaken to ascertain whether the presence of interstitial nitrogen alone could embrittle an Fe GB. If so, nitrogen in any form must be kept completely away from the grain boundaries, if not out of …
Date: September 22, 2003
Creator: Miyoung, Kim; Gellar, Clint B. & Freeman, A. F.
Object Type: Report
System: The UNT Digital Library
Electronic Properties of Hydrogen Storage Materials with Photon-in/Photon-out Soft-X-Ray Spectroscopy (open access)

Electronic Properties of Hydrogen Storage Materials with Photon-in/Photon-out Soft-X-Ray Spectroscopy

The applications of resonant soft X-ray emission spectroscopy on a variety of carbon systems have yielded characteristic fingerprints. With high-resolution monochromatized synchrotron radiation excitation, resonant inelastic X-ray scattering has emerged as a new source of information about electronic structure and excitation dynamics. Photon-in/photon-out soft-X-ray spectroscopy is used to study the electronic properties of fundamental materials, nanostructure, and complex hydrides and will offer potential in-depth understanding of chemisorption and/or physisorption mechanisms of hydrogen adsorption/desorption capacity and kinetics.
Date: September 22, 2008
Creator: Guo, Jinghua
Object Type: Article
System: The UNT Digital Library
Wet Gasification of Ethanol Residue: A Preliminary Assessment (open access)

Wet Gasification of Ethanol Residue: A Preliminary Assessment

A preliminary technoeconomic assessment has been made of several options for the application of catalytic hydrothermal gasification (wet gasification) to ethanol processing residues.
Date: September 22, 2008
Creator: Brown, Michael D. & Elliott, Douglas C.
Object Type: Report
System: The UNT Digital Library
Remaining Sites Verification Package for 132-DR-1, 1608-DR Effluent Pumping Station, Waste Site Reclassification Form 2005-035 (open access)

Remaining Sites Verification Package for 132-DR-1, 1608-DR Effluent Pumping Station, Waste Site Reclassification Form 2005-035

Radiological characterization, decommissioning and demolition of the 132-DR-1 site, 1608-DR Effluent Pumping Station was performed in 1987. The current site conditions achieve the remedial action objectives and the corresponding remedial action goals established in the Remaining Sites ROD. Residual concentrations support future land uses that can be represented by a rural-residential scenario and pose no threat to groundwater or the Columbia River based on RESRAD modeling.
Date: September 22, 2005
Creator: Carlson, R. A.
Object Type: Report
System: The UNT Digital Library
BIOASSAY VESSEL FAILURE ANALYSIS (open access)

BIOASSAY VESSEL FAILURE ANALYSIS

Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.
Date: September 22, 2008
Creator: Vormelker, P
Object Type: Article
System: The UNT Digital Library
NUCLEAR POWERED CO2 CAPTURE FROM THE ATMOSPHERE (open access)

NUCLEAR POWERED CO2 CAPTURE FROM THE ATMOSPHERE

A process for capturing CO{sub 2} from the atmosphere was recently proposed. This process uses a closed cycle of sodium and calcium hydroxide, carbonate, and oxide transformations to capture dilute CO{sub 2} from the atmosphere and to generate a concentrated stream of CO{sub 2} that is amenable to sequestration or subsequent chemical transformations. In one of the process steps, a fossil-fueled lime kiln is needed, which reduces the net CO{sub 2} capture of the process. It is proposed to replace the fossil-fueled lime kiln with a modified kiln heated by a high-temperature nuclear reactor. This will have the effect of eliminating the use of fossil fuels for the process and increasing the net CO{sub 2} capture. Although the process is suitable to support sequestration, the use of a nuclear power source for the process provides additional capabilities, and the captured CO{sub 2} may be combined with nuclear-produced hydrogen to produce liquid fuels via Fischer-Tropsch synthesis or other technologies. Conceivably, such plants would be carbon-neutral, and could be placed virtually anywhere without being tied to fossil fuel sources or geological sequestration sites.
Date: September 22, 2008
Creator: Sherman, S
Object Type: Article
System: The UNT Digital Library
Raman Scattering of Azafullerene C48N12 (open access)

Raman Scattering of Azafullerene C48N12

Raman scattering activities and Raman-active frequencies are reported for the minimum energy structure of azafullerene C{sub 48}N{sub 12} at the B3LYP/6-31G* level of theory. Analysis of the vibrational spectrum shows that the most intense IR and Raman bands are those associated with C-C vibrations, and that strong IR and Raman C-N vibrations occur below 1400 cm{sup -1}. Together with the recently reported infrared, optical absorption and x-ray spectroscopies, a complete identification of this cluster should now be feasible.
Date: September 22, 2004
Creator: Manaa, M R
Object Type: Article
System: The UNT Digital Library
Recent X-Ray Laser Experiments on the COMET Facility (open access)

Recent X-Ray Laser Experiments on the COMET Facility

The development of the transient collisional excitation x-ray laser scheme using tabletop laser systems with multiple pulse capability has progressed rapidly in the last three years. The high small-signal gain and strong x-ray output have been demonstrated for laser drive energies of typically less than 10 J. We report recent x-ray laser experiments on the Lawrence Livermore National Laboratory (LLNL) Compact Multipulse Terawatt (COMET) tabletop facility using this technique. In particular, the saturated output from the Ni-like Pd ion 4d - 4p x-ray laser at 146.8 {angstrom} has been well characterized and has potential towards a useable x-ray source in a number of applications. One important application of a short wavelength x-ray laser beam with picosecond pulse duration is the study of a high density laser-produced plasma. We report the implementation of a Mach-Zehnder type interferometer using diffraction grating optics as beam splitters designed for the Ni-like Pd laser and show results from probing a 600 ps heated plasma. In addition, gas puff targets are investigated as an x-ray laser gain medium and we report results of strong lasing on the n = 3 - 3 transitions of Ne-like Ar.
Date: September 22, 2001
Creator: Dunn, J.; Smith, R. F.; Nilsen, J.; Hunter, J. R.; Barbee, T. W.; Shlyaptsev, V. N. et al.
Object Type: Article
System: The UNT Digital Library
Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms (open access)

Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms

Implementation of a closed loop nuclear fuel cycle requires the utilization of Pu-containing MOX fuels with the important side effect of increased production of the transplutonium actinides, most importantly isotopes of Am and Cm. Because the presence of these isotopes significantly impacts the long-term radiotoxicity of high level waste, it is important that effective methods for their isolation and/or transmutation be developed. Furthermore, since transmutation is most efficiently done in the absence of lanthanide fission products (high yield species with large thermal neutron absorption cross sections) it is important to have efficient procedures for the mutual separation of Am and Cm from the lanthanides. The chemistries of these elements are nearly identical, differing only in the slightly stronger strength of interaction of trivalent actinides with ligand donor atoms softer than O (N, Cl-, S). Research being conducted around the world has led to the development of new reagents and processes with considerable potential for this task. However, pilot scale testing of these reagents and processes has demonstrated the susceptibility of the new classes of reagents to radiolytic and hydrolytic degradation. In this project, separations of trivalent actinides from fission product lanthanides have been investigated in studies of 1) the extraction …
Date: September 22, 2009
Creator: Nash, Kenneth L.
Object Type: Report
System: The UNT Digital Library
2008 Kansas City Plant Annual Illness and Injury Surveillance Report (open access)

2008 Kansas City Plant Annual Illness and Injury Surveillance Report

The U.S. Department of Energy’s (DOE) commitment to assuring the health and safety of its workers includes the conduct of epidemiologic surveillance activities that provide an early warning system for health problems among workers. The Illness and Injury Surveillance Program monitors illnesses and health conditions that result in an absence of workdays, occupational injuries and illnesses, and disabilities and deaths among current workers.
Date: September 22, 2009
Creator: United States. Department of Energy. Office of Health, Safety, and Security.
Object Type: Report
System: The UNT Digital Library
Plans for Warm Dense Matter Experiments and Ife Target Experiments on Ndcx-Ii (open access)

Plans for Warm Dense Matter Experiments and Ife Target Experiments on Ndcx-Ii

The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) is currently developing design concepts for NDCX-II, the second phase of the Neutralized Drift Compression Experiment, which will use ion beams to explore Warm Dense Matter (WDM) and Inertial Fusion Energy (IFE) target hydrodynamics. The ion induction accelerator will consist of a new short pulse injector and induction cells from the decommissioned Advanced Test Accelerator (ATA) at Lawrence Livermore National Laboratory (LLNL). To fit within an existing building and to meet the energy and temporal requirements of various target experiments, an aggressive beam compression and acceleration schedule is planned. WDM physics and ion-driven direct drive hydrodynamics will initially be explored with 30 nC of lithium ions in experiments involving ion deposition, ablation, acceleration and stability of planar targets. Other ion sources which may deliver higher charge per bunch will be explored. A test stand has been built at Lawrence Berkeley National Laboratory (LBNL) to test refurbished ATA induction cells and pulsed power hardware for voltage holding and ability to produce various compression and acceleration waveforms. Another test stand is being used to develop and characterize lithium-doped aluminosilicate ion sources. The first experiments will include heating metallic targets to 10,000 K and …
Date: September 22, 2008
Creator: Waldron, W. L.; Barnard, J. J.; Bieniosek, F. M.; Friedman, A.; Henestroza, E.; Leitner, M. et al.
Object Type: Article
System: The UNT Digital Library
DUSTRAN 1.0 User’s Guide: A GIS-Based Atmospheric Dust Dispersion Modeling System (open access)

DUSTRAN 1.0 User’s Guide: A GIS-Based Atmospheric Dust Dispersion Modeling System

The U.S. Department of Energy’s Pacific Northwest National Laboratory just completed a multi-year project to develop a fully tested and documented atmospheric dispersion modeling system (DUST TRANsport or DUSTRAN) to assist the U.S. Department of Defense in addressing particulate air quality issues at military training and testing ranges. This manual documents the DUSTRAN modeling system and includes installation instructions, a user’s guide, and detailed example tutorials.
Date: September 22, 2006
Creator: Allwine, K Jerry; Rutz, Frederick C.; Shaw, William J.; Rishel, Jeremy P.; Fritz, Brad G.; Chapman, Elaine G. et al.
Object Type: Report
System: The UNT Digital Library
LLNL History and Current Activities (open access)

LLNL History and Current Activities

None
Date: September 22, 2006
Creator: Oravetz, A. & Goulart, S.
Object Type: Article
System: The UNT Digital Library
Improved Method for CKM Constraints in Charmless Three-body B and Bs Decays (open access)

Improved Method for CKM Constraints in Charmless Three-body B and Bs Decays

Recently Ciuchini, Pierini and Silvestrini proposed a method for constraining CKM parameters in B {yields} K{pi}{pi} and B{sub s} {yields} K{pi}{pi} through phase measurements of amplitudes involving I = 3/2 K*{pi} final states. We show that complementary information on CKM parameters may be obtained by studying the phases of {Delta}I = 1 B {yields} (K*{pi}){sub I = 1/2}, B{sub s} {yields} (K* {bar K}){sub l=1} and B{sub s} {yields} ({bar K}* K){sub I=1} amplitudes. Hadronic uncertainties in these constraints from electroweak penguin operators O{sub 9} and O{sub 10}, studied using flavor SU(3), are shown to be very small in B {yields} K{pi}{pi} and B{sub s} {yields} K{pi}{pi} and somewhat larger in B{sub s} {yields} K{bar K}{pi}. The first processes imply a precise linear relation between {bar {rho}} and {bar {eta}}, with a measurable slope and an intercept at {bar {eta}} = 0 involving a theoretical error of 0.03. The decays B{sub s} {yields} K{pi}{pi} permit a measurement of involving a theoretical error below a degree. We note that while time-dependence is required when studying B{sup 0} decays at the {Upsilon}(4S), it is not needed when studying B{sub s} decays at hadronic colliders.
Date: September 22, 2006
Creator: Gronau, Michael; /SLAC, /Technion; Pirjol, Dan; /MIT, LNS; Soni, Amarjit; /Brookhaven et al.
Object Type: Article
System: The UNT Digital Library