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Development of odd-Z-projectile reactions for transactinide element synthesis

Description: The development of new odd-Z-projectile reactions leading to the production of transactinide elements is described. The cross section of the even-Z-projectile 208Pb(64Ni, n)271Ds reaction was measured at two new energies using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. In total, seven decay chains attributable to 271Ds were observed. These data, combined with previous results, establish an excitation function for the production of 271Ds. The maximum cross section was 20 +15 -11 pb at a center-of-target energy of 311.5 MeV in the laboratory frame.The data from the 271Ds experiments were used to estimate the optimum beam energy for the new odd-Z-projectile 208Pb(65Cu, n)272-111 reaction using the Fusion by Diffusion theory proposed by Swiatecki, Siwek-Wilczynska, and Wilczynski. A cross section for this reaction was measured for the first time, at a center-of-target energy of 321.1 MeV in the laboratory frame. The excitation energy f or compound nuclei formed at the target center was 13.2 MeV. One decay chain was observed, resulting in a measured cross section of 1.7 +3.9 -1.4 pb. This decay chain is in good agreement with previously published data on the decay of 272-111.The new odd-Z-projectile 208Pb(55Mn, n)262Bh reaction was studied at three different projectile energies, and 33 decay chains of 262Bh were observed. The existence of a previously reported alpha-decaying isomeric state in this nuclide was confirmed. Production of the ground state was preferred at all three beam energies. The maximum cross section was 540 +180 -150 pb at a projectile center-of-target energy of 264.0 MeV. This cross section is much larger than that previously reported for the even-Z-projectile 209Bi(54Cr, n)262Bh reaction, which may be because the 54Cr projectile energies in the latter reaction were too high for optimum production of the 1n product. At the highest projectile energy of 268.0 MeV in ...
Date: November 4, 2004
Creator: Folden III, Charles Marvin
Partner: UNT Libraries Government Documents Department

Calibrated Properties Model

Description: The purpose of this model report is to document the calibrated properties model that provides calibrated property sets for unsaturated zone (UZ) flow and transport process models (UZ models). The calibration of the property sets is performed through inverse modeling. This work followed, and was planned in, ''Technical Work Plan (TWP) for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Sections 1.2.6 and 2.1.1.6). Direct inputs to this model report were derived from the following upstream analysis and model reports: ''Analysis of Hydrologic Properties Data'' (BSC 2004 [DIRS 170038]); ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (BSC 2004 [DIRS 169855]); ''Simulation of Net Infiltration for Present-Day and Potential Future Climates'' (BSC 2004 [DIRS 170007]); ''Geologic Framework Model'' (GFM2000) (BSC 2004 [DIRS 170029]). Additionally, this model report incorporates errata of the previous version and closure of the Key Technical Issue agreement TSPAI 3.26 (Section 6.2.2 and Appendix B), and it is revised for improved transparency.
Date: October 4, 2004
Creator: Ghezzehej, T.
Partner: UNT Libraries Government Documents Department

Valence band hybridization in N-rich GaN1-xAsx alloys

Description: We have used photo-modulated transmission and optical absorption spectroscopies to measure the composition dependence of interband optical transitions in N-rich GaN{sub 1-x}As{sub x} alloys with x up to 0.06. The direct bandgap gradually decreases as x increases. In the dilute x limit, the observed band gap approaches 2.8 eV; this limiting value is attributed to a transition between the As localized level, which has been previously observed in As-doped GaN at 0.6 eV above the valence band maximum in As-doped GaN, and the conduction band minimum. The structure of the valence band of GaN{sub 1-x}As{sub x} is explained by the hybridization of the localized As states with the extended valence band states of GaN matrix. The hybridization is directly confirmed by soft x-ray emission experiments. To describe the electronic structure of the GaN{sub 1-x}As{sub x} alloys in the entire composition range a linear interpolation is used to combine the effects of valence band hybridization in N-rich alloys with conduction band anticrossing in As-rich alloys.
Date: May 4, 2004
Creator: Wu, J.; Walukiewicz, W.; Yu, K.M.; Denlinger, J.D.; Shan, W.; Ager III, J.W. et al.
Partner: UNT Libraries Government Documents Department

Design and Construction of Main Group Element-Containing Molecules and Molecule-Derived Materials With Unusual Electronic, Optical, and Magnetic Properties

Description: This program was successful in achieving its primary objectives. Namely, succeeded in the development of multiple synthetic routes to a wide variety of new candidate CVD precursor compounds.
Date: August 4, 2004
Creator: Diel, B. N.
Partner: UNT Libraries Government Documents Department

Exploration of ion-antiproton instabilities in the Recycler Ring

Description: Instabilities driven by ions (or electrons) trapped within the space charge potential of a circulating beam are common in accelerators and storage rings. In the recycler, the stored antiproton ({bar p}) beam could trap positive ions (H{sub 2}{sup +}, CO{sup +}, etc.). Conditions for trapping are discussed, and trapping potentials are calculated. Ion trapping can be reduced by clearing electrodes, a beam-free gap (or gaps), and beam shaking. Tune shifts, coherent instabilities and other effects of trapped ions on stored {bar p}'s are discussed. A ''fast-ion'' instability mode is also possible. Experiments to determine conditions and consequences of such instability in the recycler are discussed.
Date: August 4, 2004
Creator: Neuffer, David V.
Partner: UNT Libraries Government Documents Department

Evaluation of Proposed New LLW Disposal Activity Disposal of LLW in a Mega Trench rather than in Slit Trenches

Description: The effect of disposing of low-level waste in a much larger trench than the slit trenches analyzed in the revised performance assessment for the E-Area low-level waste facility is evaluated. The conclusion of the evaluation is that such disposal is bounded by the performance assessment if two restrictions are imposed. These restrictions are: the radionuclide inventory limits for slit trench disposal derived from the revised performance assessment, rather than the radionuclide concentration or package limits, are applied to the larger trench. For stabilized waste radionuclide concentration or package limits derived from the inventory limits for these wasteforms calculated in the performance assessment and the volumetric waste capacity of the entire MegaTrench may be used if this waste fills a large-enough segment of the trench to provide structural support for the closure cap, as assumed in the performance assessment and the stabilized waste is segregated from the unstabilized waste by emplacing the stabilized waste along the edge of the trench and separating the stabilized waste from the unstabilized waste by a minimum of two feet of soil or other material with similar hydraulic properties.
Date: May 4, 2004
Creator: WILHITE, ELMERL.
Partner: UNT Libraries Government Documents Department

VUV Spectroscopy in DIII-D Divertor

Description: The research carried out on this grant was motivated by the high power emission from the CIV doublet at 155 nm in the DIII-D divertor and to study the characteristics of the radiative divertor. The radiative divertor is designed to reduce the heat load to the target plates of the divertor by reducing the energy in the divertor plasma using upstream scrape-off-layer (SOL) radiation. In some cases, particularly in Partially Detached Divertor (PDD) operations, this emission accounts for more than 50% of the total radiation from the divertor. In PDD operation, produced by neutral gas injection, the particle flow to the target plate and the divertor temperature are significantly reduced. A father motivation was to study the CIV emission distribution in the lower, open divertor and the upper baffled divertor. Two Vacuum Ultra Violet Tangential viewing Television cameras (VUV TTV) were constructed and installed in the upper, baffled and the lower, open divertor. The images recorded by these cameras were then inverted to produce two-dimensional distributions of CIV in the poloidal plane. Results obtained in the project are summarized in this report.
Date: November 4, 2004
Creator: Punjabi, Alkesh & Jalufka, Nelson
Partner: UNT Libraries Government Documents Department

Sediment studies of the biological factors controlling the reduction of U(VI).

Description: Studies were conducted primarily with sediments, both in laboratory incubations and in a field experiment, with supporting studies with pure cultures. To our knowledge the sediment studies were the first on microbial U(VI) reduction in actual uranium-contaminated subsurface sediments, under conditions that mimic those found in situ. Important findings included: (1) U(VI) reduction is a biotic process in subsurface sediments. (2) U(VI) reduction can be stimulated most effectively with the addition of acetate. Although it had been speculated that microbial U(VI) reduction might be capable of this type of environmental remediation ever since the discovery of microbial U(VI) reduction, this had not been previously demonstrated under environmentally relevant conditions. (3) U(VI) is reduced concurrently with Fe(III) and prior to sulfate reduction. U(VI) and Fe(III) reduction proceeded concurrently, accompanied by a dramatic enrichment in organisms in the Geobacteraceae. Sulfate-reducing microorganisms do not appear to be important components of the microbial community reducing U(VI) in these subsurface sediments. (4) Nitrate has important influences on U(VI) reduction. Nitrate inhibits the reduction of metals until nitrate is depleted. Fe(III)-reducing microorganisms such as Geobacter metallireducens and Desulfitobacterium species can oxidize Fe(II) with the reduction of nitrate which is an important consideration because our previous studies have demonstrated that freshly precipitated Fe(III) oxides can reoxidize U(IV) to U(VI). The discovery that G. metallireducens can ''run backwards'' and oxidize U(IV) when nitrate is present reveals another mechanism preventing precipitation of U(IV) in the presence of nitrate as well as potential novel strategy for removing uranium from the subsurface after a site has been remediated. (5) Importance of understanding Fe(III) forms available for microbial reduction. Fe(III) is orders of magnitude more abundant than U(VI) as an electron acceptor to support microbial growth. It was demonstrated that poorly crystalline Fe(III) oxides and structural Fe(III) in clays are the predominant ...
Date: August 4, 2004
Creator: Lovley, derek, R.
Partner: UNT Libraries Government Documents Department

Searches for Higgs at CDF

Description: The Higgs boson is predicted to play a crucial role in the dynamics of electroweak symmetry breaking. The search for this yet-unseen state is an important part of the Run 2 physics program at the Tevatron. Herein is offered a brief description of the latest Run 1 Higgs results from CDF, as well as an early Run 2 result.
Date: March 4, 2004
Creator: Neu, C.
Partner: UNT Libraries Government Documents Department

A physically based numerical approach for modeling fracture-matrix interaction in fractured reservoirs

Description: Modeling fracture-matrix interaction within a multiple-phase flow system is a key issue for fractured reservoir simulation. Commonly used mathematical models for dealing with such interactions employ dual- or multiple-continuum concepts, in which fractures and matrix are represented as overlapping, different, but interconnected continua, described by parallel sets of conservation equations. The conventional single-point upstream weighting scheme is most commonly used to estimate flow mobility for fracture-matrix flow. However, such a scheme may have serious limitations or flaws, which lead to unphysical solutions or significant numerical errors. To overcome the limitations of the conventional upstream weighting scheme, this paper presents a physically based modeling approach for estimating physically correct relative permeability in calculating multiphase flow between fractures and the matrix, using continuity of capillary pressure at the fracture-matrix interface. The proposed approach has been implemented into two multiphase reservoir simulators and verified using analytical solutions and laboratory experimental data. The new method is demonstrated to be accurate, numerically efficient, and easy to implement in dual- or multiple-continuum reservoir simulators.
Date: May 4, 2004
Creator: Wu, Yu-Shu & Pruess, Karsten
Partner: UNT Libraries Government Documents Department

A node-centered local refinement algorithm for poisson's equation in complex geometries

Description: This paper presents a method for solving Poisson's equation with Dirichlet boundary conditions on an irregular bounded three-dimensional region. The method uses a nodal-point discretization and adaptive mesh refinement (AMR) on Cartesian grids, and the AMR multigrid solver of Almgren. The discrete Laplacian operator at internal boundaries comes from either linear or quadratic (Shortley-Weller) extrapolation, and the two methods are compared. It is shown that either way, solution error is second order in the mesh spacing. Error in the gradient of the solution is first order with linear extrapolation, but second order with Shortley-Weller. Examples are given with comparison with the exact solution. The method is also applied to a heavy-ion fusion accelerator problem, showing the advantage of adaptivity.
Date: May 4, 2004
Creator: McCorquodale, Peter; Colella, Phillip; Grote, David P. & Vay, Jean-Luc
Partner: UNT Libraries Government Documents Department

Analysis of Hydrologic Properties Data

Description: This analysis report describes the methods used to determine hydrologic properties based on the available field data from the unsaturated zone (UZ) at Yucca Mountain, Nevada. The technical scope, content, and management of this analysis report are described in the planning document ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Sections 2, 4, and 8). Fracture and matrix properties are developed by analyzing available survey data from the Exploratory Studies Facility (ESF), the Enhanced Characterization of Repository Block (ECRB) Cross-Drift, and/or boreholes; air-injection testing data from surface boreholes and from boreholes in the ESF; and data from laboratory testing of core samples. In addition, the report ''Geologic Framework Model'' (GFM2000) (BSC 2004 [DIRS 170029]) also serves as a source report by providing the geological framework model of the site. This report is a revision of the model report under the same title (BSC 2003 [DIRS 161773]), which in turn superceded the analysis report under the same title. The principal purpose of this work is to provide representative uncalibrated estimates of fracture and matrix properties for use in the model report Calibrated Properties Model. The term ''uncalibrated'' is used to distinguish the properties or parameters estimated in this report from those obtained from the inversion modeling used in ''Calibrated Properties Model''. The present work also provides fracture geometry properties for generating dual-permeability grids as documented in the scientific analyses report, ''Development of Numerical Grids for UZ Flow and Transport Modeling''.
Date: October 4, 2004
Creator: Pan, L.
Partner: UNT Libraries Government Documents Department

Development of Chemical Treatment Alternatives for Tetraphenylborate Destruction in Tank 48H

Description: This study assessed chemical treatment options for decomposing the tetraphenylborate in High Level Waste (HLW) Tank 48H. Tank 48H, located at the Savannah River Site in Aiken, SC, contains approximately one million liters of HLW. The tetraphenylborate slurry represents legacy material from commissioning of an In Tank Precipitation process to separate radioactive cesium and actinides from the non radioactive chemicals. During early operations, the process encountered an unplanned chemical reaction that catalytically decomposed the excess tetraphenylborate producing benzene. Subsequent research indicated that personnel could not control the operations within the existing equipment to both meet the desired treatment rate for the waste and maintain the benzene concentration within allowable concentrations. Since then, the Department of Energy selected an alternate treatment process for handling high-level waste at the site. However, the site must destroy the tetraphenylborate before returning the tank to HLW service. The research focuses on identifying treatments to decompose tetraphenylborate to the maximum extent feasible, with a preference for decomposition methods that produce carbon dioxide rather than benzene. A number of experiments examined whether the use of oxidants, catalysts or acids proved effective in decomposing the tetraphenylborate. Additional experiments developed an understanding of the solid, liquid and gas decomposition products. The testing identified several successful treatment options including: an iron catalyst combined with hydrogen peroxide (Fenton's reagent) with added acid; sodium permanganate with added acid; and copper catalyst with added acid. A mistake occurred in the selection and make-up of the Tank 48H simulant recipe which led to an under representation of the amount of monosodium titanate and insoluble sludge solids compared to the simulant target. The amount of added MST and sludge proved about a factor of 40 low relative to the measured Tank 48H values. The MST and sludge are insoluble solids that were likely inert in ...
Date: May 4, 2004
Creator: LAMBERT, DANIELP.
Partner: UNT Libraries Government Documents Department

Highly charged ion research at the Livermore electron beam ion traps

Description: Spectroscopy performed with the three Livermore electron beam ion traps is reviewed, which is continuing and complementing the innumerable contributions to atomic physics provided over the years by heavy-ion accelerators. Numerous spectrometers were developed that cover the spectral bands from the visible to the hard x ray region. These enabled exhaustive line surveys useful for x-ray astrophysics and for systematic studies along iso-electronic sequences, such as the 4s-4p, 3s-3p, and 2s-2p transitions in ions of the Cu-I, Na-I, and Li-I sequences useful for studying QED and correlation effects as well as for precise determinations of atomic-nuclear interactions. They also enabled measurements of radiative transition probabilities of very long-lived (milli- and microseconds) and very short-live (femtosecond) levels. Because line excitation processes can be controlled by choice of the electron beam energy, the observed line intensities are used to infer cross sections for electron-impact excitation, dielectronic recombination, resonance excitation, and innershell ionization. These capabilities have recently been expanded to simulate x-ray emission from comets by charge exchange. Specific contributions to basic atomic physics, nuclear physics, and high-temperature diagnostics are illustrated.
Date: January 4, 2004
Creator: Beiersdorfer, P
Partner: UNT Libraries Government Documents Department

lightsources.org: An Internet Site for Light SourceCommunication

Description: Research at the world's accelerator- (storage-ring and linac) based light sources is one of the most dynamic and rapidly growing fields of science. It frequently results in direct benefits to society, thereby demonstrating the value of the research with very concrete examples, but this is not widely understood or appreciated outside of the immediate user community. Our growing group of light source communicators from facilities in Europe, Asia, and the Americas, inspired by the Interactions.org Web site created by high-energy (elementary-particle)physics communicators, concluded that a light source community Web site (lightsources.org) would be the best tool for establishing effective collaboration between the communications offices of the world's light sources and to maximize the impact of our efforts. We envision lightsources.org to serve as a one-stop-shopping site for information about all aspects of light sources and the research they make possible. Audiences to be served include science communicators, the press, policymakers, the light source community, the wider scientific community, the science-interested public, and students and educators. Our proposal has been sent to the world's light source facility directors by J. Murray Gibson (APS) and William G. Stirling (ESRF). As a result,light sources.org is now being supported by a growing list of facilities from Europe, North America, and Asia. We hope to launch lightsources.org before the end of 2004.
Date: October 4, 2004
Creator: Robinson, Art
Partner: UNT Libraries Government Documents Department

Beat wave injection of electrons into plasma waves using two interfering laser pulses

Description: An electron injector concept that uses a single injection laser pulse colliding with a pump laser pulse in a plasma is analyzed. The pump pulse generates a large amplitude laser wakefield (plasma wave). The counter propagating injection pulse collides with the pump laser pulse to generate a beat wave with a slow phase velocity. The ponderomotive force of the slow beat wave is responsible for injecting plasma electrons into the wakefield near the back of the pump pulse. Test particle simulations indicate that significant amounts of charge can be trapped and accelerated ({approx} 10 pC). For higher charge, beam loading limits the validity of the simulations. The accelerated bunches are ultrashort ({approx} 1 fs) with good beam quality (relative energy spread of a few percent at a mean energy of {approx} 10 MeV and a normalized rms emittance on the order 0.4 mm.mrad). The effects of interaction angle and polarization are also explored, e.g., efficient trapping can occur for near-collinear geometries. Beat wave injection using a single injection pulse has the advantages of simplicity, ease of experimental implementation, and requires modest laser intensity I {approx_equal} 8.8 x 10{sup 17} W/cm{sup 2}.
Date: March 4, 2004
Creator: Fubiani, G.; Esarey, E.; Schroeder, C.B. & Leemans, W.P.
Partner: UNT Libraries Government Documents Department

Investigation of microwave transitions and nonlinear magneto-optical rotation in anti-relaxation-coated cells

Description: Using laser optical pumping, widths and frequency shifts are determined for microwave transitions between the components of the ground-state hyperfine structure for {sup 85}Rb and {sup 87}Rb atoms contained in vapor cells with alkane anti-relaxation coatings. The results are compared with data on Zeeman relaxation obtained in nonlinear magneto-optical rotation (NMOR) experiments, a comparison important for quantitative understanding of spin-relaxation mechanisms in coated cells. By comparing cells manufactured over a forty-year period we demonstrate the long-term stability of coated cells, which may be useful for atomic clocks and magnetometers.
Date: June 4, 2004
Creator: Budker, D.; Hollberg, L.; Kimball, D.F.; Kitching, J.; Pustclny, S.; Robinson, H.G. et al.
Partner: UNT Libraries Government Documents Department

Large aperture micro-focus KB mirrors for spectroscopy experiments at the Advanced Light Source

Description: General purpose refocus mirrors using Kirkpatrick-Baez geometry have been designed, built and installed at a new undulator beam-line facility to provide spot sizes smaller than 10 microns for specialized spectroscopy experiments at the Advanced Light Source. All the available flux is focused and the focal length is adjustable. The mirrors are fully computer controlled and can be detuned to create a spot as big as 500 microns.
Date: June 4, 2004
Creator: Warwick, T.; Andresen, N.; Comins, J.; Franck, A.; Gilles, M.; Tonnessen, T. et al.
Partner: UNT Libraries Government Documents Department