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Experimental Determination of Apery-Like Identities forZeta(2n+2) (open access)

Experimental Determination of Apery-Like Identities forZeta(2n+2)

We document the discovery of two generating functions forzeta(2n+2), analogous to earlier work for zeta(2n+1) and zeta(4n+3),initiated by Koecher and pursued further by Borwein, Bradley andothers.
Date: May 11, 2005
Creator: Bailey, David H.; Borwein, Jonathan M. & Bradley, David M.
System: The UNT Digital Library
Use of Quantitative Uncertainty Analysis to Support M&VDecisions in ESPCs (open access)

Use of Quantitative Uncertainty Analysis to Support M&VDecisions in ESPCs

Measurement and Verification (M&V) is a critical elementof an Energy Savings Performance Contract (ESPC) - without M&V, thereisno way to confirm that the projected savings in an ESPC are in factbeing realized. For any given energy conservation measure in an ESPC,there are usually several M&V choices, which will vary in terms ofmeasurement uncertainty, cost, and technical feasibility. Typically,M&V decisions are made almost solely based on engineering judgmentand experience, with little, if any, quantitative uncertainty analysis(QUA). This paper describes the results of a pilot project initiated bythe Department of Energy s Federal Energy Management Program to explorethe use of Monte-Carlo simulation to assess savings uncertainty andthereby augment the M&V decision-making process in ESPCs. The intentwas to use QUA selectively in combination with heuristic knowledge, inorder to obtain quantitative estimates of the savings uncertainty withoutthe burden of a comprehensive "bottoms-up" QUA. This approach was used toanalyze the savings uncertainty in an ESPC for a large federal agency.The QUA was seamlessly integrated into the ESPC development process andthe incremental effort was relatively small with user-friendly tools thatare commercially available. As the case study illustrates, in some casesthe QUA simply confirms intuitive or qualitative information, while inother cases, it provides insight that suggests revisiting …
Date: May 11, 2005
Creator: Mathew, Paul A.; Koehling, Erick & Kumar, Satish
System: The UNT Digital Library
Development of a Compact Radiography Accelerator Using Dielectric Wall Accelerator Technology (open access)

Development of a Compact Radiography Accelerator Using Dielectric Wall Accelerator Technology

None
Date: May 11, 2005
Creator: Sampayan, S.; Caporaso, G.; Chen, Y.; Hawkins, S.; Holmes, C.; McCarrick, J. et al.
System: The UNT Digital Library
Compact Neutron Generators for Medical Home Land Security andPlanetary Exploration (open access)

Compact Neutron Generators for Medical Home Land Security andPlanetary Exploration

The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0-9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration with a sub-surface material characterization on Mars. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Four main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-compact axial neutron generator for elemental analysis applications. Current status of the neutron generator development with experimental data will be presented.
Date: May 11, 2005
Creator: Reijonen, J.
System: The UNT Digital Library
Technique for the Generation of Attosecond X-Ray Pulses Using anFEL (open access)

Technique for the Generation of Attosecond X-Ray Pulses Using anFEL

We describe a technique for the generation of an isolated burst of X-ray radiation with a duration of {approx} 100 attoseconds in a free electron laser (FEL) employing self-amplified spontaneous emission. Our scheme relies on an initial interaction of the electron beam with an ultra-short laser pulse in a one-period wiggler followed by compression in a dispersive section. The result of this interaction is to create a sub-femtosecond slice of the electron beam with enhanced growth rates for FEL amplification. After many gain lengths through the FEL undulator, the X-ray output from this slice dominates the radiation of the entire bunch. We consider the impact of various effects on the efficiency of this technique. Different configurations are considered in order to realize various timing structures for the resulting radiation.
Date: May 11, 2005
Creator: Penn, G. & Zholents, A.A.
System: The UNT Digital Library
A photoemission study of Pd ultrathin films on Pt(111) (open access)

A photoemission study of Pd ultrathin films on Pt(111)

The origin of surface core-level shift (SCLS) of Pd thin films on Pt(111) substrate is investigated. At sub-monolayer coverage of Pd thin films, the splitting of Pd 3d core level peaks indicate the contribution of both initial and final-state of photo-ionization processes while there is almost no change on valence band (VB) spectra. When the coverage of Pd reaches to single monolayer, the final-state relaxation effect on the Pd 3d vanishes and only the initial-state effect, a negative SCLS, is present. Also, the VB spectrum at Pd monolayer films shows a clear band narrowing, that is the origin of the negative SCLS at monolayer coverage. As the Pd coverage is increased to more than monolayer thickness, the Pd 3d peaks start to show the surface layer contribution from second and third layers, positive SCLS, and the VB spectrum shows even narrower band width, possibly due to the formation of surface states and strained effect of Pd adlayers on top of the first pseudomorphic layer.
Date: May 11, 2005
Creator: Mun, Bongjin Simon; Lee, Choongman; Stamenkovic, Vojislav; Markovic, Nenad M. & Ross Jr., Philip N.
System: The UNT Digital Library
Highly Compressed Ion Beams for High Energy Density Science (open access)

Highly Compressed Ion Beams for High Energy Density Science

The Heavy Ion Fusion Virtual National Laboratory (HIFVNL) is developing the intense ion beams needed to drive matter to the High Energy Density (HED) regimes required for Inertial Fusion Energy (IFE) and other applications. An interim goal is a facility for Warm Dense Matter (WDM) studies, wherein a target is heated volumetrically without being shocked, so that well-defined states of matter at 1 to 10 eV are generated within a diagnosable region. In the approach we are pursuing, low to medium mass ions with energies just above the Bragg peak are directed onto thin target ''foils'', which may in fact be foams with mean densities 1% to 10% of solid. This approach complements that being pursued at GSI, wherein high-energy ion beams deposit a small fraction of their energy in a cylindrical target. We present the beam requirements for WDM experiments. We discuss neutralized drift compression and final focus experiments and modeling. We describe suitable accelerator architectures based on Drift-Tube Linac, RF, single-gap, Ionization-Front Accelerator, and Pulse-Line Ion Accelerator concepts. The last of these is being pursued experimentally in the HIF-VNL. Finally, we discuss plans toward a user facility for target experiments.
Date: May 11, 2005
Creator: Friedman, A.; Barnard, J. J.; Briggs, R. J.; Callahan, D. A.; Caporaso, G. J.; Celata, C. M. et al.
System: The UNT Digital Library
A Collaborative Informatics Infrastructure for Multi-scale Science (open access)

A Collaborative Informatics Infrastructure for Multi-scale Science

The Collaboratory for Multi-scale Chemical Science (CMCS) is developing a powerful informatics-based approach to synthesizing multi-scale information to support a systems-based research approach and is applying it in support of combustion research. An open source multi-scale informatics toolkit is being developed that addresses a number of issues core to the emerging concept of knowledge grids including provenance tracking and lightweight federation of data and application resources into cross-scale information flows. The CMCS portal is currently in use by a number of high-profile pilot groups and is playing a significant role in enabling their efforts to improve and extend community maintained chemical reference information.
Date: May 11, 2005
Creator: Myers, J. D.; Allison, T. C.; Bittner, S.; Didier, B.; Frenklach, M.; Green, W. H., Jr. et al.
System: The UNT Digital Library
A Compact High-Brightness Heavy-Ion Injector (open access)

A Compact High-Brightness Heavy-Ion Injector

To provide a compact high-brightness heavy-ion beam source for Heavy Ion Fusion (HIF) accelerators, we have been experimenting with merging multi-beamlets in an injector which uses an RF plasma source. In an 80-kV 20-microsecond experiment, the RF plasma source has produced up to 5 mA of Ar{sup +} in a single beamlet. An extraction current density of 100 mA/cm{sup 2} was achieved, and the thermal temperature of the ions was below 1 eV. We have tested at full voltage gradient the first 4 gaps of an injector design. Einzel lens were used to focus the beamlets while reducing the beamlet to beamlet space charge interaction. We were able to reach greater than 100 kV/cm in the first four gaps. We also performed experiments on a converging 119 multi-beamlet source. Although the source has the same optics as a full 1.6 MV injector system, these test were carried out at 400 kV due to the test stand HV limit. We have measured the beam's emittance after the beamlets are merged and passed through an electrostatic quadrupole (ESQ). Our goal is to confirm the emittance growth and to demonstrate the technical feasibility of building a driver-scale HIF injector.
Date: May 11, 2005
Creator: Westenskow, G A; Grote, D P; Halaxa, E; Kwan, J W & Bieniosek, F
System: The UNT Digital Library
A Multi-Bunch, Three-Dimensional, Strong-Strong Beam-Beam Simulation Code for Parallel Computers (open access)

A Multi-Bunch, Three-Dimensional, Strong-Strong Beam-Beam Simulation Code for Parallel Computers

For simulating the strong-strong beam-beam effect, using Particle-In-Cell codes has become one of the methods of choice. While the two-dimensional problem is readily treatable using PC-class machines, the three-dimensional problem, i.e., a problem encompassing hourglass and phase-averaging effects, requires the use of parallel processors. In this paper, we introduce a strong-strong code NIMZOVICH, which was specifically designed for parallel processors and which is optimally used for many bunches and parasitic crossings. We describe the parallelization scheme and give some benchmarking results.
Date: May 11, 2005
Creator: Cai, Y. & Kabel, A. C.
System: The UNT Digital Library
Electrochemical and Antimicrobial Properties of Diamondlike Carbon-Metal Composite Films (open access)

Electrochemical and Antimicrobial Properties of Diamondlike Carbon-Metal Composite Films

Implants containing antimicrobial metals may reduce morbidity, mortality, and healthcare costs associated with medical device-related infections. We have deposited diamondlike carbon-silver (DLC-Ag), diamondlike carbon-platinum (DLC-Pt), and diamondlike carbon-silver-platinum (DLC-AgPt) thin films using a multicomponent target pulsed laser deposition process. Transmission electron microscopy of the DLC-silver and DLC-platinum composite films revealed that the silver and platinum self-assemble into nanoparticle arrays within the diamondlike carbon matrix. The diamondlike carbon-silver film possesses hardness and Young's modulus values of 37 GPa and 331 GPa, respectively. The diamondlike carbon-metal composite films exhibited passive behavior at open-circuit potentials. Low corrosion rates were observed during testing in a phosphate-buffered saline (PBS) electrolyte. In addition, the diamondlike carbon-metal composite films were found to be immune to localized corrosion below 1000 mV (SCE). DLC-silver-platinum films demonstrated exceptional antimicrobial properties against Staphylococcus bacteria. It is believed that a galvanic couple forms between platinum and silver, which accelerates silver ion release and provides more robust antimicrobial activity. Diamondlike carbon-silver-platinum films may provide unique biological functionalities and improved lifetimes for cardiovascular, orthopaedic, biosensor, and implantable microelectromechanical systems.
Date: May 11, 2005
Creator: MORRISON, M. L.; BUCHANAN, R. A.; LIAW, P. K.; BERRY, C. J.; BRIGMON, R.; RIESTER, L. et al.
System: The UNT Digital Library
Inverse Free Electron Laser Heater for the LCLS (open access)

Inverse Free Electron Laser Heater for the LCLS

The Linac Coherent Light Source (LCLS) free electron laser employs an RF photocathode gun that yields a 1nC bunch a few picoseconds long, which must be further compressed to yield the high current required for Self Amplified Spontaneous Emission (SASE) gain. The electron beam from the RF photocathode gun is quite sensitive to microbunching instabilities such as coherent synchrotron radiation (CSR) in the compressor chicanes and longitudinal space charge (LSC) in the linac. These effects can be Landau damped by adding energy spread to the electron bunch prior to compression. They propose to do this by co-propagating an infrared laser beam with the electron bunch in an undulator in the LCLS injector beamline. The undulator is placed in a four bend magnet chicane to allow the Ir laser beam to propagate colinearly with the e-beam while it oscillates in the undulator. The IR laser beam is derived from the photocathode gun drive laser, so the two beams are synchronized. Simulations presented elsewhere in these proceedings show that the laser interaction damps the microbunching instabilities to a very great extent. This paper is a description of the design of the laser heater.
Date: May 11, 2005
Creator: Bentson, L. D.; Bolton, P.; Carr, R.; Dowell, D.; Emma, P.; Gilevich, S. et al.
System: The UNT Digital Library
Solving the SUSY CP problem with flavor breaking F-terms (open access)

Solving the SUSY CP problem with flavor breaking F-terms

Supersymmetric flavor models for the radiative generation of fermion masses offer an alternative way to solve the SUSY-CP problem. We assume that the supersymmetric theory is flavor and CP conserving. CP violating phases are associated to the vacuum expectation values of flavor violating susy-breaking fields. As a consequence, phases appear at tree level only in the soft supersymmetry breaking matrices. Using a U(2) flavor model as an example we show that it is possible to generate radiatively the first and second generation of quark masses and mixings as well as the CKM CP phase. The one-loop supersymmetric contributions to EDMs are automatically zero since all the relevant parameters in the lagrangian are flavor conserving and as a consequence real. The size of the flavor and CP mixing in the susy breaking sector is mostly determined by the fermion mass ratios and CKM elements. We calculate the contributions to {epsilon}, {epsilon}' and to the CP asymmetries in the B decays to {psi}K{sub s}, {phi}K{sub s}, {eta}'K{sub s} and X{sub s}{gamma}. We analyze a case study with maximal predictivity in the fermion sector. For this worst case scenario the measurements of {Delta}m{sub K}, {Delta}m{sub B} and {epsilon} constrain the model requiring extremely …
Date: May 11, 2005
Creator: Diaz-Cruz, Lorenzo J. & Ferrandis, Javier
System: The UNT Digital Library
Studies to Increase the Anti-Proton Transmission from the Targetto the Debuncher Ring (open access)

Studies to Increase the Anti-Proton Transmission from the Targetto the Debuncher Ring

The AP2 beamline at Fermilab transports anti-protons from the production target to the Debuncher ring. The measured admittance of the Debuncher ring and the theoretical aperture of the line are larger than the size of the transmitted beam. Extensive tracking studies were done using the Accelerator Toolbox (AT) to understand the sources of the difference. As simulations pointed to chromatic effects being a source of problems, measurements were done to study this. Several possible remedies were studied including adding sextupoles to the line to reduce the chromatic effects.
Date: May 11, 2005
Creator: Reichel, Ina; Zisman, Michael S.; Gollwitzer, Keith & Werkema, Steve
System: The UNT Digital Library
The Storage Ring Magnets of the Australian Synchrotron (open access)

The Storage Ring Magnets of the Australian Synchrotron

A 3 GeV Synchrotron Radiation Source is being built in Melbourne, Australia. Commissioning is foreseen in 2006. The Storage ring has a circumference of 216 m and has a 14 fold DBA structure. For the storage ring the following magnets will be installed: 28 dipoles with a field of 1.3 T, and a gradient of 3.35 T/m; 56 quadrupoles with a gradient of 18 T/m and 28 with a gradient of 10 T/m; 56 sextupoles with a strength of B'' = 350 T/m and 42 with 150 T/m. The sextupoles are equipped with additional coils for horizontal and vertical steering and for a skew quadrupole. The pole profile was determined by scaling the pole profile of the SPEAR magnets [1] to the aperture of the ASP magnets. The magnets are to be supplied by Buckley Systems Ltd in Auckland, New Zealand.
Date: May 11, 2005
Creator: Barg, B.; Jackson, A.; LeBlanc, G.; Huttel, E. & Tanabe, J.
System: The UNT Digital Library
Nanosecond-Timescale Intra-Bunch-Train Feedback for the Linear Collider: Results of the FONT2 Run (open access)

Nanosecond-Timescale Intra-Bunch-Train Feedback for the Linear Collider: Results of the FONT2 Run

We report on experimental results from the December 2003/January 2004 data run of the Feedback On Nanosecond Timescales (FONT) experiment at the Next Linear Collider Test Accelerator at SLAC. We built a second-generation prototype intra-train beam-based feedback system incorporating beam position monitors, fast analogue signal processors, a feedback circuit, fast-risetime amplifiers and stripline kickers. We applied a novel real-time charge-normalization scheme to account for beam current variations along the train. We used the system to correct the position of the 170-nanosecond-long bunchtrain at NLCTA. We achieved a latency of 53 nanoseconds, representing a significant improvement on FONT1 (2002), and providing a demonstration of intra-train feedback for the Linear Collider.
Date: May 11, 2005
Creator: Barlow, R.; Dufau, M.; Kalinin, A.; Myatt, G.; Perry, C.; Burrows, P. N. et al.
System: The UNT Digital Library
Investigations, Experiments, and Implications for using existing Pulse Magents for 'TOPOFF' Operation at the Advanced Light Source (open access)

Investigations, Experiments, and Implications for using existing Pulse Magents for 'TOPOFF' Operation at the Advanced Light Source

ALS top-off mode of operation will require injection of the electron beam from the Booster Ring into the Storage Ring at the full ALS energy level of 1.9 GeV. Currently the Booster delivers a beam at 1.5 GeV to the Storage Ring where it is then ramped to the full energy and stored for the user operation. The higher Booster beam energy will require the pulse magnets in the Booster and Storage Rings to operate at proportionally higher magnetic gap fields. Our group studied and tested the possible design and installation modifications required to operate the magnets and drivers at ''top-off'' levels. Our results and experiments show that with minor electrical modifications all the existing pulse magnet systems can be used at the higher energy levels, and the increased operational stresses should have a negligible impact on magnet reliability. Furthermore, simple electrical modifications to the storage ring thick septum will greatly reduce the present level of septum stray leakage fields into the storage ring beam.
Date: May 11, 2005
Creator: Stover, Gregory D.; Baptiste, Kenneth Michael; Barry, Walter; Gath, William; Julian, James; Kwiatkowski, Slawomir et al.
System: The UNT Digital Library
Lithium Ethylene Dicarbonate Identified as the Primary Product of Chemical and Electrochemical Reduction of EC in EC:EMC/1.2M LiPF6 Electrolyte (open access)

Lithium Ethylene Dicarbonate Identified as the Primary Product of Chemical and Electrochemical Reduction of EC in EC:EMC/1.2M LiPF6 Electrolyte

Lithium ethylene dicarbonate (CH2OCO2Li)2 was chemically synthesized and its Fourier Transform Infrared (FTIR) spectrum was obtained and compared with that of surface films formed on Ni after cyclic voltammetry (CV) in 1.2M lithium hexafluorophosphate(LiPF6)/ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3:7, w/w) electrolyte and on metallic lithium cleaved in-situ in the same electrolyte. By comparison of IR experimental spectra with that of the synthesized compound, we established that the title compound is the predominant surface species in both instances. Detailed analysis of the IR spectrum utilizing quantum chemical (Hartree-Fock) calculations indicates that intermolecular association through O...Li...O interactions is very important in this compound. It is likely that the title compound in passivation layer has a highly associated structure, but the exact intermolecular conformation could not be established based on analysis of the IR spectrum.
Date: May 11, 2005
Creator: Zhuang, Guorong V.; Xu, Kang; Yang, Hui; Jow, T. Richard & Ross, Philip N., Jr.
System: The UNT Digital Library