Focal Plane Metrology for the LSST Camera (open access)

Focal Plane Metrology for the LSST Camera

Meeting the science goals for the Large Synoptic Survey Telescope (LSST) translates into a demanding set of imaging performance requirements for the optical system over a wide (3.5{sup o}) field of view. In turn, meeting those imaging requirements necessitates maintaining precise control of the focal plane surface (10 {micro}m P-V) over the entire field of view (640 mm diameter) at the operating temperature (T {approx} -100 C) and over the operational elevation angle range. We briefly describe the hierarchical design approach for the LSST Camera focal plane and the baseline design for assembling the flat focal plane at room temperature. Preliminary results of gravity load and thermal distortion calculations are provided, and early metrological verification of candidate materials under cold thermal conditions are presented. A detailed, generalized method for stitching together sparse metrology data originating from differential, non-contact metrological data acquisition spanning multiple (non-continuous) sensor surfaces making up the focal plane, is described and demonstrated. Finally, we describe some in situ alignment verification alternatives, some of which may be integrated into the camera's focal plane.
Date: January 10, 2007
Creator: A Rasmussen, Andrew P.; Hale, Layton; Kim, Peter; Lee, Eric; Perl, Martin; Schindler, Rafe et al.
Object Type: Article
System: The UNT Digital Library
SUMMARY REPORT DIRECT PUSH TECHNOLOGY BOREHOLES FOR GEOPHYSICAL LOGGING 200-IS-1 OPERABLE UNIT FY2008 (open access)

SUMMARY REPORT DIRECT PUSH TECHNOLOGY BOREHOLES FOR GEOPHYSICAL LOGGING 200-IS-1 OPERABLE UNIT FY2008

None
Date: February 10, 2009
Creator: AK, LEE
Object Type: Report
System: The UNT Digital Library
Prediction of Coal ash leaching behavior in acid mine water, comparison of laboratory and field studies (open access)

Prediction of Coal ash leaching behavior in acid mine water, comparison of laboratory and field studies

Strongly alkaline fluidized bed combustion ash is commonly used to control acid mine drainage in West Virginia coal mines. Objectives include acid neutralization and immobilization of the primary AMD pollutants: iron, aluminum and manganese. The process has been successful in controlling AMD though doubts remain regarding mobilization of other toxic elements present in the ash. In addition, AMD contains many toxic elements in low concentrations. And, each mine produces AMD of widely varying quality. So, predicting the effect of a particular ash on a given coal mine's drainage quality is of particular interest. In this chapter we compare the results of a site-specific ash leaching procedure with two large-scale field applications of FBC ash. The results suggested a high degree of predictability for roughly half of the 25 chemical parameters and poor predictability for the remainder. Of these, seven parameters were successfully predicted on both sites: acidity, Al, B, Ba, Fe, Ni and Zn while electrical conductivity, Ca, Cd, SO4, Pb and Sb were not successfully predicted on either site. Trends for the remaining elements: As, Ag, Be, Cu, Cr, Hg, Mg, Mn, pH, Se Tl and V were successfully predicted on one but not both mine sites.
Date: January 10, 2005
Creator: ANNA, KNOX
Object Type: Report
System: The UNT Digital Library
Electric Reliability: Options for Electric Transmission Infrastructure Improvements (open access)

Electric Reliability: Options for Electric Transmission Infrastructure Improvements

The electric utility industry is inherently capital intensive. At the same time, the industry must operate under a changing and sometimes unpredictable regulatory system at both the federal and state level. The Energy Policy Act of 2005 has set in place government activities intended to relieve congestion on the transmission system. Several factors have contributed to the lack of new transmission capacity; these are outlined within this report. This report also discusses earlier pieces of energy legislation.
Date: June 10, 2005
Creator: Abel, Amy
Object Type: Report
System: The UNT Digital Library
Electricity: The Road Toward Restructuring (open access)

Electricity: The Road Toward Restructuring

This report talks about Electricity regulation and transmission issues. It also includes the history of the California Electricity Crisis.
Date: August 10, 2004
Creator: Abel, Amy
Object Type: Report
System: The UNT Digital Library
Longitudinal double-spin asymmetry and cross section for inclusivejet production in polarized proton collisions at sqrt(s) = 200 GeV (open access)

Longitudinal double-spin asymmetry and cross section for inclusivejet production in polarized proton collisions at sqrt(s) = 200 GeV

We report a measurement of the longitudinal double-spinasymmetry A_LL and the differential cross section for inclusivemidrapidity jet production in polarized proton collisions at sqrt(s)=200GeV. The cross section data cover transverse momenta 5<pT<50GeV/c and agree with next-to-leading order perturbative QCD evaluations.The A_LL data cover 5<pT<17 GeV/c and disfavor at 98 percentC.L. maximal positive gluon polarization in the polarizednucleon.
Date: August 10, 2006
Creator: Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type: Article
System: The UNT Digital Library
SEISMIC SOURCE SCALING AND DISCRIMINATION IN DIVERSE TECTONIC ENVIRONMENTS (open access)

SEISMIC SOURCE SCALING AND DISCRIMINATION IN DIVERSE TECTONIC ENVIRONMENTS

The objectives of this study are to improve low-magnitude regional seismic discrimination by performing a thorough investigation of earthquake source scaling using diverse, high-quality datasets from varied tectonic regions. Local-to-regional high-frequency discrimination requires an estimate of how earthquakes scale with size. Walter and Taylor (2002) developed the MDAC (Magnitude and Distance Amplitude Corrections) method to empirically account for these effects through regional calibration. The accuracy of these corrections has a direct impact on our ability to identify clandestine explosions in the broad regional areas characterized by low seismicity. Unfortunately our knowledge of source scaling at small magnitudes (i.e., m{sub b} &lt; {approx}4.0) is poorly resolved. It is not clear whether different studies obtain contradictory results because they analyze different earthquakes, or because they use different methods. Even in regions that are well studied, such as test sites or areas of high seismicity, we still rely on empirical scaling relations derived from studies taken from half-way around the world at inter-plate regions. We investigate earthquake sources and scaling from different tectonic settings, comparing direct and coda wave analysis methods. We begin by developing and improving the two different methods, and then in future years we will apply them both to each …
Date: July 10, 2007
Creator: Abercrombie, Rachel E.; Mayeda, Kevin; Walter, William R.; Viegas, Gisela M. & Murphy, Katherine
Object Type: Article
System: The UNT Digital Library
Migration and Entrapment of DNAPLs in Heterogeneous Systems: Impact of Waste and Porous Medium Composition (open access)

Migration and Entrapment of DNAPLs in Heterogeneous Systems: Impact of Waste and Porous Medium Composition

Dense nonaqueous phase liquids (DNAPLs) pose a significant threat to soil and groundwater at Department of Energy (DOE) sites. Evidence suggests that subsurface wettability variations are present at many of these sites as a result of spatical and temporal variations in aqueous phase chemistry, contaminant aging, mineralogy and organic matter. The presence of such heterogeneity may significantly influence DNAPL migration and entrapment in the saturated zone.
Date: January 10, 2005
Creator: Abriola, Linda M. & Demond, Avery H.
Object Type: Report
System: The UNT Digital Library
Environmental Whole-Genome Amplification to Access Microbial Diversity in Contaminated Sediments (open access)

Environmental Whole-Genome Amplification to Access Microbial Diversity in Contaminated Sediments

Low-biomass samples from nitrate and heavy metal contaminated soils yield DNA amounts that have limited use for direct, native analysis and screening. Multiple displacement amplification (MDA) using ?29 DNA polymerase was used to amplify whole genomes from environmental, contaminated, subsurface sediments. By first amplifying the genomic DNA (gDNA), biodiversity analysis and gDNA library construction of microbes found in contaminated soils were made possible. The MDA method was validated by analyzing amplified genome coverage from approximately five Escherichia coli cells, resulting in 99.2 percent genome coverage. The method was further validated by confirming overall representative species coverage and also an amplification bias when amplifying from a mix of eight known bacterial strains. We extracted DNA from samples with extremely low cell densities from a U.S. Department of Energy contaminated site. After amplification, small subunit rRNA analysis revealed relatively even distribution of species across several major phyla. Clone libraries were constructed from the amplified gDNA, and a small subset of clones was used for shotgun sequencing. BLAST analysis of the library clone sequences showed that 64.9 percent of the sequences had significant similarities to known proteins, and ''clusters of orthologous groups'' (COG) analysis revealed that more than half of the sequences from …
Date: December 10, 2005
Creator: Abulencia, C. B.; Wyborski, D. L.; Garcia, J.; Podar, M.; Chen, W.; Chang, S. H. et al.
Object Type: Article
System: The UNT Digital Library
Education Vouchers: Constitutional Issues and Cases (open access)

Education Vouchers: Constitutional Issues and Cases

This report details the constitutional standards that currently apply to indirect aid programs and summarizes all of the pertinent state and federal court decisions, including the Ohio case that will be heard by the Supreme Court. On September 25, 2001, the Supreme Court agreed to review a case raising the controversial issue of the constitutionality of education vouchers. In Zelman v. Simmons-Harris the Sixth Circuit held Ohio’s Pilot Scholarship Program, which provided up to $2500 to help low-income students in Cleveland’s public schools attend private schools in the city, to violate the establishment of religion clause of the First Amendment.
Date: September 10, 2002
Creator: Ackerman, David M.
Object Type: Report
System: The UNT Digital Library
Global Climate Change: Selected Legal Questions About the Kyoto Protocol (open access)

Global Climate Change: Selected Legal Questions About the Kyoto Protocol

This report addresses legal issues after the United States signed the Kyoto Protocol to the UnitedNations Framework Convention on Climate Change. The protocol is not yet in effect internationally and cannot be legally binding on the U.S. unless and until the Senate gives its advice and consent.
Date: January 10, 2001
Creator: Ackerman, David M.
Object Type: Report
System: The UNT Digital Library
Composition and structure of sputter deposited erbium hydride thin films (open access)

Composition and structure of sputter deposited erbium hydride thin films

Erbium hydride thin films are grown onto polished, a-axis {alpha} Al{sub 2}O{sub 3} (sapphire) substrates by reactive ion beam sputtering and analyzed to determine composition, phase and microstructure. Erbium is sputtered while maintaining a H{sub 2} partial pressure of 1.4 x 10{sup {minus}4} Torr. Growth is conducted at several substrate temperatures between 30 and 500 C. Rutherford backscattering spectrometry (RBS) and elastic recoil detection analyses after deposition show that the H/Er areal density ratio is approximately 3:1 for growth temperatures of 30, 150 and 275 C, while for growth above {approximately}430 C, the ratio of hydrogen to metal is closer to 2:1. However, x-ray diffraction shows that all films have a cubic metal sublattice structure corresponding to that of ErH{sub 2}. RBS and Auger electron that sputtered erbium hydride thin films are relatively free of impurities.
Date: May 10, 2000
Creator: Adams, David P.; Romero, Juan A.; Rodriguez, Mark A.; Floro, Jerrold A. & Banks, James C.
Object Type: Article
System: The UNT Digital Library
Pulse length dependence of laser conditioning and bulk damage in KD2PO4 (open access)

Pulse length dependence of laser conditioning and bulk damage in KD2PO4

An experimental technique has been developed to measure the damage density {rho}({phi}) variation with fluence from scatter maps of bulk damage sites in plates of KD{sub 2}PO{sub 4} (DKDP) crystals combined with calibrated images of the damaging beam's spatial profile. Unconditioned bulk damage in tripler-cut DKDP crystals has been studied using 351 nm (3 {omega}) light at pulse lengths of 0.055, 0.091, 0.30, 0.86, 2.6, and 10 ns. It is found that there is less scatter due to damage at fixed fluence for longer pulse lengths. The results also show that for all the pulse lengths the scatter due to damage is a strong function of the damaging fluence. It is determined that the pulse length scaling for bulk damage scatter in unconditioned DKDP material varies as {tau}{sup 0.24 {+-} 0.05} over two orders of magnitude of pulse lengths. The effectiveness of 3 {omega} laser conditioning at pulse lengths of 0.055, 0.096, 0.30, 0.86, 3.5, and 23 ns is analyzed in term of damage density {rho}({phi}) at 3 {omega}, 2.6 ns. The 860 ps conditioning to a peak irradiance of 7 GW/cm{sup 2} had the best performance under 3 {omega}, 2.6 ns testing. It is shown that the optimal conditioning …
Date: November 10, 2004
Creator: Adams, J. J.; Weiland, T. L.; Stanley, J. R.; Sell, W. D.; Luthi, R. L.; Vickers, J. L. et al.
Object Type: Article
System: The UNT Digital Library
Transverse-momentum dependent modification of dynamic texture in central Au+Au collisions at sqrt(sNN) = 200 GeV (open access)

Transverse-momentum dependent modification of dynamic texture in central Au+Au collisions at sqrt(sNN) = 200 GeV

Correlations in the hadron distributions produced in relativistic Au+Au collisions are studied in the discrete wavelet expansion method. The analysis is performed in the space of pseudorapidity (|{eta}| {le} 1) and azimuth (full 2{pi}) in bins of transverse momentum (p{sub t}) from 0.14 {le} p{sub t} {le} 2.1 GeV/c. In peripheral Au+Au collisions a correlation structure ascribed to minijet fragmentation is observed. It evolves with collision centrality and p{sub t} in a way not seen before which suggests strong dissipation of minijet fragmentation in the longitudinally-expanding medium.
Date: January 10, 2005
Creator: Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D.; Arkhipkin, D. et al.
Object Type: Article
System: The UNT Digital Library
General computational spectroscopic framework applied to Z-pinch dynamic hohlraum K-shell argon spectra (open access)

General computational spectroscopic framework applied to Z-pinch dynamic hohlraum K-shell argon spectra

We describe a general computational spectroscopic framework for interpreting observed spectra. The framework compares synthetic spectra with measured spectra, then optimizes the agreement using the Dakota toolkit to minimize a merit function that incorporates established spectroscopic techniques. We generate synthetic spectra using the self-consistent nonlocal thermodynamic equilibrium atomic kinetics and radiative transfer code Cretin, relativistic atomic structure and cross section data from Hullac, and detailed spectral line shapes from Totalb. We test the capabilities of both our synthetic spectra model and general spectroscopic framework by analyzing a K-shell argon spectrum from a Z-pinch dynamic hohlraum inertial confinement fusion capsule implosion experiment. The framework obtains close agreement between an experimental spectrum measured by a time integrated focusing spectrometer and the optimal synthetic spectrum. The synthetic spectra show that considering the spatial extent of the capsule and including the effects of optically thick resonance lines significantly affects the interpretation of measured spectra.
Date: January 10, 2005
Creator: Adams, M L; Sinars, D B & Scott, H A
Object Type: Article
System: The UNT Digital Library
Synthesis and Characterization of Cluster-Derived Supported Bimetallic Catalysts (open access)

Synthesis and Characterization of Cluster-Derived Supported Bimetallic Catalysts

New procedures have been developed for synthesizing di- and tri-metallic cluster complexes. The chemical properties of the new complexes have been investigated, particularly toward the activation of molecular hydrogen. These complexes were then converted into bi- and tri-metallic nanoparticles on silica and alumina supports. These nanoparticles were characterized by electron microscopy and were then tested for their ability to produce catalytic hydrogenation of unsaturated hydrocarbons and for the preferential oxidation of CO in the presence of hydrogen. The bi- and tri-metallic nanoparticles exhibited far superior activity and selectivity as hydrogenation catalysts when compared to the individual metallic components. It was found that the addition of tin greatly improved the selectivity of the catalysts for the hydrogenation of polyolefins. The addition of iron improves the catalysts for the selective oxidation of CO by platinum in the presence of hydrogen. The observations should lead to the development of lower cost routes to molecules that can be used to produce polymers and plastics for use by the general public and for procedures to purify hydrogen for use as an alternative energy in the hydrogen economy of the future.
Date: October 10, 2008
Creator: Adams, Richard D & Amiridis, Michael D
Object Type: Report
System: The UNT Digital Library
Experience with copper oxide production in antiproton source components at Fermi National Accelerator Laboratory (open access)

Experience with copper oxide production in antiproton source components at Fermi National Accelerator Laboratory

The Antiproton (Pbar) Source at Fermi National Accelerator Laboratory is a facility comprised of a target station, two rings called the Debuncher and Accumulator and the transport lines between those rings and the remainder of the particle accelerator complex. Water is by far the most common medium for carrying excess heat away from components, primarily electromagnets, in this facility. The largest of the water systems found in Pbar is the 95 degree Fahrenheit Low Conductivity Water (LCW) system. LCW is water which has had free ions removed, increasing its resistance to electrical current. This water circuit is used to cool magnets, power supplies, and stochastic cooling components and typically has a resistivity of 11--18 megaohms-cm. For more than ten years the Antiproton rings were plagued with overheating magnets due to plugged water-cooling channels. Various repairs have been tried over the years with no permanent success. Throughout all of this time, water samples have indicated copper oxide, CuO, as the source of the contamination. Matters came to a head in early 1997 following a major underground LCW leak between the Central Utilities Building and the Antiproton Rings enclosures. Over a span of several weeks following system turn-on, some twenty magnets overheated …
Date: May 10, 2000
Creator: Ader, Christine R.; Jr., Elvin R. Harms & Morgan, and James P.
Object Type: Article
System: The UNT Digital Library
Flavor Structure of Warped Extra Dimension Models (open access)

Flavor Structure of Warped Extra Dimension Models

We recently showed, in hep-ph/0406101, that warped extra dimensional models with bulk custodial symmetry and few TeV KK masses lead to striking signals at B-factories. In this paper, using a spurion analysis, we systematically study the flavor structure of models that belong to the above class. In particular we find that the profiles of the zero modes, which are similar in all these models, essentially control the underlying flavor structure. This implies that our results are robust and model independent in this class of models. We discuss in detail the origin of the signals in B-physics. We also briefly study other NP signatures that arise in rare K decays (K {yields} {pi}{nu}{nu}), in rare top decays [t {yields} c{gamma}(Z, gluon)] and the possibility of CP asymmetries in D{sup 0} decays to CP eigenstates such as K{sub s}{pi}{sup 0} and others. Finally we demonstrate that with light KK masses, {approx} 3 TeV, the above class of models with anarchic 5D Yukawas has a ''CP problem'' since contributions to the neutron electric dipole moment are roughly 20 times larger than the current experimental bound. Using AdS/CFT correspondence, these extra-dimensional models are dual to a purely 4D strongly coupled conformal Higgs sector thus …
Date: August 10, 2004
Creator: Agashe, Kaustubh; Perez, Gilad & Soni, Amarjit
Object Type: Article
System: The UNT Digital Library
U.S.-European Union Trade Relations: Issues and Policy Challenges (open access)

U.S.-European Union Trade Relations: Issues and Policy Challenges

None
Date: September 10, 2003
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
U.S.-European Union Trade Relations: Issues and Policy Challenges (open access)

U.S.-European Union Trade Relations: Issues and Policy Challenges

None
Date: September 10, 2002
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
U.S.-European Union Trade Relations: Issues and Policy Challenges (open access)

U.S.-European Union Trade Relations: Issues and Policy Challenges

None
Date: February 10, 2005
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
Merlot Design (open access)

Merlot Design

We describe Merlot, a system for delivery of digital imagery over high speed networks. We describe various use cases, the client/server interaction, and the image and network codecs. We also describe some possible applications using Merlot and future work.
Date: June 10, 2003
Creator: Ahern, S D
Object Type: Text
System: The UNT Digital Library
Developing High Brightness and High Current Beams for HIF Injectors (open access)

Developing High Brightness and High Current Beams for HIF Injectors

The US Heavy Ion Fusion Virtual National Laboratory is continuing research into ion sources and injectors that simultaneously provide high current (0.5-1.0 Amps) and high brightness (normalized emittance better than 1.0 {pi}-mm-mr). The central issue of focus is whether to carry on the traditional approach of large surface ionization sources or to adopt a multi-aperture approach that transports many smaller ''beamlets'' separately at low energies before allowing them to merge. For the large surface source, the recent commissioning of the 2-MeV injector for the High Current experiment has increased our understanding of the beam quality limitations for these sources. We have also improved our techniques for fabricating large diameter aluminosilicate sources to improve lifetime and emission uniformity. For the multi-aperture approach we are continuing to study the feasibility of small surface sources and a RF induced plasma source in preparation for beamlet merging experiments, while continuing to run computer simulations for better understanding of this alternate concept. Experiments into both architectures will be performed on a newly commissioned ion source test stand at LLNL called the STS-500. This stand test provides a platform for testing a variety of ion sources and accelerating structures with 500 kV, 17-microsecond pulses. Recent progress …
Date: May 10, 2002
Creator: Ahle, L & Kwan, J W
Object Type: Article
System: The UNT Digital Library
Inversion of Airborne Contaminants in a Regional Model (open access)

Inversion of Airborne Contaminants in a Regional Model

We are interested in a DDDAS problem of localization of airborne contaminant releases in regional atmospheric transport models from sparse observations. Given measurements of the contaminant over an observation window at a small number of points in space, and a velocity field as predicted for example by a mesoscopic weather model, we seek an estimate of the state of the contaminant at the beginning of the observation interval that minimizes the least squares misfit between measured and predicted contaminant field, subject to the convection-diffusion equation for the contaminant. Once the ''initial'' conditions are estimated by solution of the inverse problem, we issue predictions of the evolution of the contaminant, the observation window is advanced in time, and the process repeated to issue a new prediction, in the style of 4D-Var. We design an appropriate numerical strategy that exploits the spectral structure of the inverse operator, and leads to efficient and accurate resolution of the inverse problem. Numerical experiments verify that high resolution inversion can be carried out rapidly for a well-resolved terrain model of the greater Los Angeles area.
Date: January 10, 2007
Creator: Akcelik, V.; Biros, G.; Draganescu, A.; Ghattas, O.; Hill, J.; van Bloemen Waanders, B. et al.
Object Type: Article
System: The UNT Digital Library