Proton Polarimetry at the Relativistic Heavy Ion Collider (open access)

Proton Polarimetry at the Relativistic Heavy Ion Collider

The RHIC polarized proton collider employs polarimeters in each of the Blue and Yellow rings that utilize the analyzing power in p-Carbon elastic scattering in the Coulomb Nuclear Interference region to measure the absolute beam polarization. These are calibrated by the polarized Hydrogen Jet Target that measures the absolute beam polarization in pp elastic scattering in the CNI region. This paper describes the status and performance of these polarimeters in the FY09 run which included both a 250 GeV/c and 100 GeV/c physics data taking periods. We will describe some of the difficulties encountered and the efforts underway to improve the performance in better energy resolution, rate handling capability, and reduced systematic uncertainties.
Date: September 7, 2009
Creator: Makdisi, Y.; Aschenauer, E.; Atoian, G.; Bazilevsky, A.; Bunce, G.; Gill, R. et al.
Object Type: Article
System: The UNT Digital Library
Tracking the Sun IV: An Historical Summary of the Installed Cost of Photovoltaics in the United States from 1998 to 2010 (open access)

Tracking the Sun IV: An Historical Summary of the Installed Cost of Photovoltaics in the United States from 1998 to 2010

The present report describes installed cost trends for grid-connected PV projects installed from 1998 through 2010 (with some limited and preliminary results presented for projects installed in the first six months of 2011). The analysis is based on project-level cost data from approximately 116,500 residential, non-residential, and utility-sector PV systems in the United States. The inclusion of utility-sector PV is a new element in this year’s report. The combined capacity of all systems in the data sample totals 1,685 MW, equal to 79% of all grid-connected PV capacity installed in the United States through 2010 and representing one of the most comprehensive sources of installed PV cost data for the U.S. Based on this dataset, the report describes historical installed cost trends over time, and by location, market segment, technology type, and component. The report also briefly compares recent PV installed costs in the United States to those in Germany and Japan, and describes trends in customer incentives for PV installations and net installed costs after receipt of such incentives. The analysis presented here focuses on descriptive trends in the underlying data, serving primarily to summarize the data in tabular and graphical form.
Date: September 7, 2011
Creator: Darghouth, Naim & Wiser, Ryan
Object Type: Report
System: The UNT Digital Library
Experimental Plans to Explore Dielectric Wakefield Acceleration in the THZ Regime (open access)

Experimental Plans to Explore Dielectric Wakefield Acceleration in the THZ Regime

Dielectric wakefield accelerators have shown great promise toward high-gradient acceleration. We investigate the performances of a possible experiment under consideration at the FLASH facility in DESY to explore wakefield acceleration with an enhanced transformer ratio. The experiment capitalizes on a unique pulse shaping capability recently demonstrated at this facility. In addition, the facility incorporates a superconducting linear accelerator that could generate bunch trains with closely spaced bunches thereby opening the exploration of potential dynamical effects in dielectric wakefield accelerators.
Date: September 7, 2011
Creator: Lemery, F.; Mihalcea, D.; U., /Northern Illinois; Piot, P.; /Fermilab; Behrens, C. et al.
Object Type: Article
System: The UNT Digital Library
Representing Range Compensators with Computational Geometry in TOPAS (open access)

Representing Range Compensators with Computational Geometry in TOPAS

In a proton therapy beamline, the range compensator modulates the beam energy, which subsequently controls the depth at which protons deposit energy. In this paper, we introduce two computational representations of range compensator. One of our compensator representations, which we refer to as a subtraction solid-based range compensator, precisely represents the compensator. Our other representation, the 3D hexagon-based range compensator, closely approximates the compensator geometry. We have implemented both of these compensator models in a proton therapy Monte Carlo simulation called TOPAS (Tool for Particle Simulation). In the future, we will present a detailed study of the accuracy and runtime performance trade-offs between our two range compensator representations.
Date: September 7, 2012
Creator: Iandola, Forrest N. & /Illinois U., Urbana /SLAC
Object Type: Report
System: The UNT Digital Library
RF Systems in a Neutrino Factory (open access)

RF Systems in a Neutrino Factory

Based on existing sources, I compile parameters for the RF systems for a neutrino factory which accelerates to 10 GeV.
Date: September 7, 2012
Creator: Berg, J. S.
Object Type: Report
System: The UNT Digital Library
ADDITIVE TESTING FOR IMPROVED SULFUR RETENTION: PRELIMINARY REPORT (open access)

ADDITIVE TESTING FOR IMPROVED SULFUR RETENTION: PRELIMINARY REPORT

The Savannah River National Laboratory is collaborating with Alfred University to evaluate the potential for additives in borosilicate glass to improve sulfur retention. This preliminary report provides further background on the incorporation of sulfur in glass and outlines the experiments that are being performed by the collaborators. A simulated waste glass composition has been selected for the experimental studies. The first phase of experimental work will evaluate the impacts of BaO, PbO, and V{sub 2}O{sub 5} at concentrations of 1.0, 2.0, and 5.0 wt % on sulfate retention in simulated high level waste borosilicate glass. The second phase of experimental work will evaluate the effects of time at the melt temperature on sulfur retention. The resulting samples will be characterized to determine the amount of sulfur remaining as well as to identify the formation of any crystalline phases. The results will be used to guide the future selection of frits and glass forming chemicals in vitrifying Department of Energy wastes containing high sulfur concentrations.
Date: September 7, 2011
Creator: Amoroso, J. & Fox, K.
Object Type: Report
System: The UNT Digital Library
Materials Performance in USC Steam (open access)

Materials Performance in USC Steam

Materials Performance in USC Steam: (1) pressure effects on steam oxidation - unique capability coming on-line; (2) hydrogen evolution - hydrogen permeability apparatus to determine where hydrogen goes during steam oxidation; and (3) NETL materials development - steam oxidation resource for NETL developed materials.
Date: September 7, 2011
Creator: Holcomb, G. R.; Tylczak, J.; Meier, G. H. & Yanar, N. M.
Object Type: Article
System: The UNT Digital Library
Vacuum engineering for fusion research and fusion reactors (open access)

Vacuum engineering for fusion research and fusion reactors

The following topics are described: (1) surface pumping by cryogenic condensation, (2) operation of large condensing cryopumps, (3) pumping for large fusion experiments, and (4) vacuum technology for fusion reactors. (MOW)
Date: September 7, 1976
Creator: Pittenger, L. C.
Object Type: Article
System: The UNT Digital Library
Alternative Energy Center, Final Scientific/Technical Report (open access)

Alternative Energy Center, Final Scientific/Technical Report

The Lansing Community College Alternative Energy Center was created with several purposes in mind. The first purpose was the development of educational curricula designed to meet the growing needs of advanced energy companies that would allow students to articulate to other educational institutions or enter this growing workforce. A second purpose was the professional development of faculty and teachers to prepare them to train tomorrow's workforce and scholars. Still another purpose was to design, construct, and equip an alternative energy laboratory that could be used for education, demonstration, and public outreach. Last, the Center was to engage in community outreach and education to enhance industry partnerships, inform decision makers, and increase awareness and general knowledge of hydrogen and other alternative energy technologies and their beneficial impacts on society. This project has enabled us to accomplish all of our goals, including greater faculty understanding of advanced energy concepts, who are now able to convey this knowledge to students through a comprehensive alternative energy curriculum, in a facility well-equipped with advanced technologies, which is also being used to better educate the public on the advantages to society of exploring alternative energy technologies.
Date: September 7, 2007
Creator: Dillman, Howard D. & Marshall, JaNice C.
Object Type: Report
System: The UNT Digital Library
South Asian Summer Monsoon and Its Relationship with ENSO in the IPCC AR4 Simulations (open access)

South Asian Summer Monsoon and Its Relationship with ENSO in the IPCC AR4 Simulations

In this paper we use the extensive integrations produced for the IPCC Fourth Assessment Report (AR4) to examine the relationship between ENSO and the monsoon at interannual and decadal timescales. We begin with an analysis of the monsoon simulation in the 20th century integrations. Six of the 18 models were found to have a reasonably realistic representation of monsoon precipitation climatology. For each of these six models SST and anomalous precipitation evolution along the equatorial Pacific during El Nino events display considerable differences when compared to observations. Out of these six models only four (GFDL{_}CM{_}2.0, GFDL{_}CM{_}2.1, MRI, and MPI{_}ECHAM5) exhibit a robust ENSO-monsoon contemporaneous teleconnection, including the known inverse relationship between ENSO and rainfall variations over India. Lagged correlations between the all-India rainfall (AIR) index and Nino3.4 SST reveal that three models represent the timing of the teleconnection, including the spring predictability barrier which is manifested as the transition from positive to negative correlations prior to the monsoon onset. Furthermore, only one of these three models (GFDL{_}CM{_}2.1) captures the observed phase lag with the strongest anticorrelation of SST peaking 2-3 months after the summer monsoon, which is partially attributable to the intensity of simulated El Nino itself. We find that …
Date: September 7, 2005
Creator: Annamalai, H.; Hamilton, K. & Sperber, K. R.
Object Type: Article
System: The UNT Digital Library
Fully Atomistic Simulations of Hydrodynamic Instabilities and Mixing (open access)

Fully Atomistic Simulations of Hydrodynamic Instabilities and Mixing

The large-scale computational capabilities at LLNL make it possible to develop seamless connections from processes at the atomic scale to complex macroscopic phenomena such as hydrodynamic instabilities and turbulent mixing. Traditionally, these connections have been made by combining results from different scientific fields. For gases and fluids, atomic and molecular scattering cross sections must first be obtained and incorporated into Boltzmann transport equations. Their solution yields then transport coefficients which are input parameters for the Navier-Stokes equations for fluid dynamics. The latter are solved numerically with hydro-codes. For visco-elastic solids, on the other hand, atomistic simulations must first provide constitutive laws for the mobility and multiplication of dislocations and other crystalline defects. In turn, these laws are utilized to construct meso-scale models for plastic deformation. These models are then incorporated into hydro- and finite element codes to predict the macroscopic behavior of solid materials. Many of these intermediate steps can be bypassed with large-scale molecular dynamics simulations. For this purpose, codes have been developed in which trajectories of atoms or molecules are mapped onto continuum field descriptions for mass density, mass flow, stresses, and for temperature. It is now possible to compare directly and quantitatively atomistic simulations with predictions from …
Date: September 7, 2006
Creator: Kubota, A & Wolfer, W G
Object Type: Report
System: The UNT Digital Library
Inclusive Lambda_c Production in e+e- Annihilations at sqrt{s}=10.54 GeV and in Upsilon(4S) Decays (open access)

Inclusive Lambda_c Production in e+e- Annihilations at sqrt{s}=10.54 GeV and in Upsilon(4S) Decays

We present measurements of the total production rates and momentum distributions of the charmed baryon {Lambda}{sub c}{sup +} in e{sup +}e{sup -} {yields} hadrons at a center-of-mass energy of 10.54 GeV and in {Upsilon}(4S) decays. In hadronic events at 10.54 GeV, charmed hadrons are almost exclusively leading particles in e{sup +}e{sup -} {yields} c{bar c} events, allowing direct studies of c-quark fragmentation. We measure a momentum distribution for {Lambda}{sub c}{sup +} baryons that differs significantly from those measured previously for charmed mesons. Comparing with a number of models, we find none that can describe the distribution completely. We measure an average scaled momentum of (x{sub p}) = 0.574 {+-} 0.009 and a total rate of N{sub {Lambda}{sub c}}{sup q{bar q}} = 0.057 {+-} 0.002(exp.) {+-} 0.015(BF) {Lambda}{sub c}{sup +} per hadronic event, where the experimental error is much smaller than that due to the branching fraction into the reconstructed decay mode, pK{sup -} {pi}{sup +}. In {Upsilon}(4S) decays we measure a total rate of N{sub {Lambda}{sub c}}{sup {Upsilon}} = 0.091 {+-} 0.006(exp.) {+-} 0.024(BF) per {Upsilon}(4S) decay, and find a much softer momentum distribution than expected from B decays into a {Lambda}{sub c}{sup +} plus an antinucleon and one to …
Date: September 7, 2006
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Surface Energy Anisotropy Effects on Pore-Channel Stability:Rayleigh Instabilities in m-Plane Sapphire (open access)

Surface Energy Anisotropy Effects on Pore-Channel Stability:Rayleigh Instabilities in m-Plane Sapphire

Internal, high-aspect-ratio pore channels with their long axes parallel to the m(10{bar 1}0) plane of sapphire were generated through sequential application of photolithography, ion-beam etching and solid-state diffusion bonding. The axial orientation of channels within the m plane was systematically varied to sample a range of bounding-surface crystallographies. The morphologic evolution of these pore channels during anneals at 1700 C was recorded by postanneal optical microscopy. The development and growth of periodic axial variations in the pore channel radius was observed, and ultimately led to the formation of discrete pores. The wavelength and average pore spacing, assumed to reflect the kinetically dominant perturbation wavelength, varied with the in-plane pore channel orientation, as did the time for complete channel breakup. Results are compared to those previously obtained when pore channels were etched into c(0001)-plane sapphire and annealed under similar conditions. The results indicate a strong effect of surface stability on the evolution behavior.
Date: September 7, 2005
Creator: Santala, Melissa K. & Glaeser, Andreas M.
Object Type: Article
System: The UNT Digital Library
Inherent Negative Biases in the Generalized Geometry Holdup (GGH) Model (open access)

Inherent Negative Biases in the Generalized Geometry Holdup (GGH) Model

None
Date: September 7, 2006
Creator: Oberer, R. B.; Gunn, C. A. & Chiang, L. G.
Object Type: Report
System: The UNT Digital Library
SAES St 909 Getter Testing at the Savannah River National Laboratory (open access)

SAES St 909 Getter Testing at the Savannah River National Laboratory

Process gas tritium stripper technology has gone from catalytic oxidation followed by absorption on molecular sieve/zeolite beds to non-evaporate metal getter technology. SAES Getters produces a number of commercial getter products including St 909. St 909, a Zr-Mn-Fe alloy, is sold in pellet form, can decompose (''crack'') a number of process gas impurities, and retains lower levels of tritium than other getters. The performance of this material to remove process impurities, especially methane, under of variety of operating conditions has been part of a Savannah River National Laboratory (SRNL) for five years. St 909 has been tested at the bench (6 gram) scale, the pilot (500 gram) scale, and at the full (5300) gram scale under a variety of test conditions. This paper gives a brief summary of test results obtained for the different scale tests.
Date: September 7, 2005
Creator: Klein, J. E. & Holder, J. E
Object Type: Article
System: The UNT Digital Library
Study of the Exclusive Initial State RadiationProduction of the D \bar D System (open access)

Study of the Exclusive Initial State RadiationProduction of the D \bar D System

A study of exclusive production of the D{bar D} system through initial-state radiation is performed in a search for charmonium states, where D = D{sup 0} or D{sup +}. The D{sup 0} mesons are reconstructed in the D{sup 0} {yields} K{sup -}{pi}{sup +}, D{sup 0} {yields} K{sup -}{pi}{sup +}{pi}{sup 0}, and D{sup 0} {yields} K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} decay modes. The D{sup +} is reconstructed through the D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +} decay mode. The analysis makes use of an integrated luminosity of 288.5 fb{sup -1} collected by the BABAR experiment. The D{bar D} mass spectrum shows a clear {psi}(3770) signal. Further structures appear in the 3.9 and 4.1 GeV/c{sup 2} regions. No evidence is found for Y(4260) decays to D{bar D}, implying an upper limit {Beta}(Y(4260) {yields} D{bar D})/{Beta}(Y(4260) {yields} J/{psi}{pi}{sup +}{pi}{sup -}) < 7.6 (95% confidence level).
Date: September 7, 2006
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Implementing Strategies for Drying and Pressing Wood Without Emissions Controls (open access)

Implementing Strategies for Drying and Pressing Wood Without Emissions Controls

Drying and pressing wood for the manufacture of lumber, particleboard, oriented strand board (OSB), veneer and medium density fiberboard (MDF) release volatile organic compounds (VOCs) into the atmosphere. These emissions require control equipment that are capital-intensive and consume significant quantities of natural gas and electricity. The objective of our work was to understand the mechanisms through which volatile organic compounds are generated and released and to develop simple control strategies. Of the several strategies developed, two have been implemented for OSB manufacture over the course of this study. First, it was found that increasing final wood moisture by about 2-4 percentage points reduced the dryer emissions of hazardous air pollutants by over 70%. As wood dries, the escaping water evaporatively cools the wood. This cooling tapers off wood when the wood is nearly dry and the wood temperature rises. Thermal breakdown of the wood tissue occurs and VOCs are released. Raising the final wood moisture by only a few percentage points minimizes the temperature rise and reduces emissions. Evaporative cooling also impacts has implications for VOC release from wood fines. Flaking wood for OSB manufacture inevitable generates fines. Fines dry out rapidly because of their high surface area and evaporative …
Date: September 7, 2007
Creator: Banerjee, Sujit & Conners, Terrance
Object Type: Report
System: The UNT Digital Library
The Dynamics of an Isolated Plasma Filament at the Edge of a Toroidal Device (open access)

The Dynamics of an Isolated Plasma Filament at the Edge of a Toroidal Device

None
Date: September 7, 2006
Creator: Ryutov, D. D.
Object Type: Article
System: The UNT Digital Library
An Approach to Industrial Stormwater Benchmarks: Establishing and Using Site-Specific Threshold Criteria at Lawrence Livermore National Laboratory (open access)

An Approach to Industrial Stormwater Benchmarks: Establishing and Using Site-Specific Threshold Criteria at Lawrence Livermore National Laboratory

Current regulatory schemes use generic or industrial sector specific benchmarks to evaluate the quality of industrial stormwater discharges. While benchmarks can be a useful tool for facility stormwater managers in evaluating the quality stormwater runoff, benchmarks typically do not take into account site-specific conditions, such as: soil chemistry, atmospheric deposition, seasonal changes in water source, and upstream land use. Failing to account for these factors may lead to unnecessary costs to trace a source of natural variation, or potentially missing a significant local water quality problem. Site-specific water quality thresholds, established upon the statistical evaluation of historic data take into account these factors, are a better tool for the direct evaluation of runoff quality, and a more cost-effective trigger to investigate anomalous results. Lawrence Livermore National Laboratory (LLNL), a federal facility, established stormwater monitoring programs to comply with the requirements of the industrial stormwater permit and Department of Energy orders, which require the evaluation of the impact of effluent discharges on the environment. LLNL recognized the need to create a tool to evaluate and manage stormwater quality that would allow analysts to identify trends in stormwater quality and recognize anomalous results so that trace-back and corrective actions could be initiated. …
Date: September 7, 2006
Creator: Campbell, C G & Mathews, S
Object Type: Article
System: The UNT Digital Library
Three-Dimensional Photonic Crystal Laser-Driven Accelerator Structures (open access)

Three-Dimensional Photonic Crystal Laser-Driven Accelerator Structures

We discuss simulated photonic crystal structure designs for laser-driven particle acceleration, focusing on three-dimensional planar structures based on the so-called ''woodpile'' lattice. We describe guiding of a speed-of-light accelerating mode by a defect in the photonic crystal lattice and discuss the properties of this mode, including particle beam dynamics and potential coupling methods for the structure. We also discuss possible materials and power sources for this structure and their effects on performance parameters, as well as possible manufacturing techniques and the required tolerances. In addition we describe the computational technique and possible improvements in numerical modeling that would aid development of photonic crystal structures.
Date: September 7, 2006
Creator: Cowan, B.
Object Type: Article
System: The UNT Digital Library
Evidence Of Rapid Localized Groundwater Transport In Volcanic Tuffs Beneath Yucca Mountain, Nevada (open access)

Evidence Of Rapid Localized Groundwater Transport In Volcanic Tuffs Beneath Yucca Mountain, Nevada

At Yucca Mountain, Nevada-the proposed location for a national high-level nuclear waste repository-radionuclides, if released from breached waste storage canisters, could make their way down through the unsaturated zone (where the repository would be located) into the underlying groundwater and eventually back to the biosphere (i.e., where they could adversely affect human health). The compliance boundary, 18 km south of the proposed repository, is defined as the location where a human being using groundwater would be maximally exposed to radionuclides outside of an exclusion zone set around the repository. It is thus important to predict how these radionuclides would be transported by the groundwater flow, and to predict both the concentration of and the rate at which any leaked radionuclides would arrive at the compliance boundary. We recently conducted a study of groundwater flux in the saturated zone through the Crater Flat Group, in a wellbore 15 km south of the proposed repository. The Crater Flat Group, a sequence of ash-flow tuff formations, is laterally extensive beneath the footprint of the proposed repository. Because of its intense fracturing and high permeabilities, the Bullfrog tuff is the primary unit within the Cratei Flat Group through which radionuclides would be transported, as …
Date: September 7, 2006
Creator: Freifeld, B.; Doughty, C.; Walker, J.; Kryder, L.; Gilmore, K.; Finsterle, S. et al.
Object Type: Report
System: The UNT Digital Library
CLIMATIC FORECASTING OF NET INFILTRATION AT YUCCA MOUNTAIN, USING ANALOGUE METEOROLOGICAL DATA (open access)

CLIMATIC FORECASTING OF NET INFILTRATION AT YUCCA MOUNTAIN, USING ANALOGUE METEOROLOGICAL DATA

Net infiltration is a key hydrologic parameter that controls the rate of deep percolation through the unsaturated zone, the groundwater recharge, radionuclide transport, and seepage into the underground tunnels. Because net infiltration is largely affected by climatic conditions, future changes in climatic conditions will potentially alter net infiltration. The objectives of this presentation are to: (1) Present a conceptual model and a semi-empirical approach for regional, climatic forecasting of net infiltration, based on the precipitation and temperature data from analogue meteorological stations, and (2) Demonstrate the results of forecasting net infiltration for future climates--interglacial, monsoon and glacial--over the Yucca Mountain region for the period of 500,000 years. Calculations of the net infiltration were performed using a modified Budyko's water-balance model, for which potential evapotranspiration was evaluated from the temperature-based Thornthwaite formula. (Both Budyko's and Thornthwaite's formulae have been used broadly in hydrological studies.) The results of calculations were used for ranking net infiltration, along with the aridity and precipitation-effectiveness (P-E) indexes, for future climatic scenarios. Using this approach, we determined a general trend of increasing net infiltration from the present-day (interglacial) climate to monsoon, intermediate (glacial transition), and then to the glacial climate. Ranking of the aridity and P-E indexes …
Date: September 7, 2005
Creator: Faybishenko, B.
Object Type: Report
System: The UNT Digital Library
XTOD - XES Interface Control Document (open access)

XTOD - XES Interface Control Document

This document describes the interface between the LCLS XTOD System (WBS No.1.5) and the LCLS XES (WBS No.1.6). The interface locations ranging from the beam dump to the far experimental hall are identified. Subsystems that connect at or cross the boundary are identified.
Date: September 7, 2005
Creator: Trent, J
Object Type: Report
System: The UNT Digital Library
Optical Damage Threshold of Silicon for Ultrafast Infrared Pulses (open access)

Optical Damage Threshold of Silicon for Ultrafast Infrared Pulses

While silicon has several properties making it an attractive material for structure-based laser-driven acceleration, its optical damage threshold, a key parameter for high-gradient acceleration, has been unknown. Here we present measurements of the optical damage threshold of crystalline silicon for ultrafast pulses in the mid-infrared. The wavelengths tested span a range from the telecommunications band at 1550 nm extending longer toward the two-photon absorption threshold at around 2200 nm. We discuss the prevailing theories of ultrafast optical breakdown, describe the experimental setup and preliminary results, and propose a relevant performance parameter for candidate accelerator structures.
Date: September 7, 2006
Creator: Cowan, B.
Object Type: Article
System: The UNT Digital Library