IBS for RHIC operation below transition energy and various RF systems (open access)

IBS for RHIC operation below transition energy and various RF systems

N/A
Date: February 13, 2013
Creator: A., Fedotov
Object Type: Report
System: The UNT Digital Library
Search for neutral Higgs bosons in the multi-b-jet topology in 5.2fb-1 of ppbar collisions at sqrt(s)=1.96 TeV (open access)

Search for neutral Higgs bosons in the multi-b-jet topology in 5.2fb-1 of ppbar collisions at sqrt(s)=1.96 TeV

None
Date: June 13, 2013
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D. et al.
Object Type: Article
System: The UNT Digital Library
Detection of the Energetic Pulsar PSR B1509-58 And Its Pulsar Wind Nebula in MSH 15-52 Using the Fermi-Large Area Telescope (open access)

Detection of the Energetic Pulsar PSR B1509-58 And Its Pulsar Wind Nebula in MSH 15-52 Using the Fermi-Large Area Telescope

None
Date: September 13, 2011
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Allafort, A.; Asano, K.; Baldini, L. et al.
Object Type: Article
System: The UNT Digital Library
Fermi Large Area Telescope Observation of a Gamma-Ray Source at the Position of Eta Carinae (open access)

Fermi Large Area Telescope Observation of a Gamma-Ray Source at the Position of Eta Carinae

None
Date: June 13, 2013
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J. et al.
Object Type: Article
System: The UNT Digital Library
Gamma-Ray Emission Concurrent with the Nova in the Symbiotic Binary V407 Cygni (open access)

Gamma-Ray Emission Concurrent with the Nova in the Symbiotic Binary V407 Cygni

None
Date: June 13, 2013
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Baldini, L.; Ballet, J. et al.
Object Type: Article
System: The UNT Digital Library
MULTIDENTATE TEREPHTHALAMIDATE AND HYDROXYPYRIDONATE LIGANDS: TOWARDS NEW ORALLY ACTIVE CHELATORS (open access)

MULTIDENTATE TEREPHTHALAMIDATE AND HYDROXYPYRIDONATE LIGANDS: TOWARDS NEW ORALLY ACTIVE CHELATORS

The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using {sup 59}Fe, {sup 238}Pu, and {sup 241}Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.
Date: July 13, 2011
Creator: Abergel, Rebecca J. & Raymond, Kenneth N.
Object Type: Article
System: The UNT Digital Library
Spectroscopic Analyses of the Biofuels-Critical Phytochemical Coniferyl Alcohol and Its Enzyme-Catalyzed Oxidation Products (open access)

Spectroscopic Analyses of the Biofuels-Critical Phytochemical Coniferyl Alcohol and Its Enzyme-Catalyzed Oxidation Products

Lignin composition (monolignol types of coniferyl, sinapyl or p-coumaryl alcohol) is causally related to biomass recalcitrance. We describe multiwavelength (220, 228, 240, 250, 260, 290, 295, 300, 310 or 320 nm) absorption spectroscopy of coniferyl alcohol and its laccase- or peroxidase-catalyzed products during real time kinetic, pseudo-kinetic and endpoint analyses, in optical turn on or turn off modes, under acidic or basic conditions. Reactions in microwell plates and 100 mu L volumes demonstrated assay miniaturization and high throughput screening capabilities. Bathochromic and hypsochromic shifts along with hyperchromicity or hypochromicity accompanied enzymatic oxidations by laccase or peroxidase. The limits of detection and quantitation of coniferyl alcohol averaged 2.4 and 7.1 mu M respectively, with linear trend lines over 3 to 4 orders of magnitude. Coniferyl alcohol oxidation was evident within 10 minutes or with 0.01 mu g/mL laccase and 2 minutes or 0.001 mu g/mL peroxidase. Detection limit improved to 1.0 mu M coniferyl alcohol with Km of 978.7 +/- 150.7 mu M when examined at 260 nm following 30 minutes oxidation with 1.0 mu g/mL laccase. Our assays utilized the intrinsic spectroscopic properties of coniferyl alcohol or its oxidation products for enabling detection, without requiring chemical synthesis or modification of …
Date: July 13, 2011
Creator: Achyuthan, Komandoor; Adams, Paul; Simmons, Blake & Singh, Anup
Object Type: Article
System: The UNT Digital Library
Measurement of Separate Cosmic-Ray Electron And Positron Spectra with the Fermi Large Area Telescope (open access)

Measurement of Separate Cosmic-Ray Electron And Positron Spectra with the Fermi Large Area Telescope

None
Date: May 13, 2013
Creator: Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Barbiellini, G.; Bastieri, D. et al.
Object Type: Article
System: The UNT Digital Library
Constraints on the Cosmic-Ray Density Gradient Beyond the Solar Circle From Fermi Gamma-Ray Observations of the Third Galactic Quadrant (open access)

Constraints on the Cosmic-Ray Density Gradient Beyond the Solar Circle From Fermi Gamma-Ray Observations of the Third Galactic Quadrant

We repot an analysis of the interstellar ϒ-ray emission in the third Galactic quadrant measured by he Fermi Large Area Telescope. The window encompassing the Galactic plane from longitude 210° to 250° has kinematically well-defined segments of the Local and the Perseus arms, suitable to study the cosmic-ray densities across the outer Galaxy. We measure no large gradient with Galactocentric distance of the ϒ-ray eissivitties per interstellar H atom over the regions sampled in this study. The gradient depends, however, on the optical depth correction applied to derive the H1 column densities. No significant variations are found in the interstellar spectra in the outer Galaxy, indicating similar shapes of the cosmic-ray spectrum up to the Perseus arm for particles with GeV to tens of GeV energies. The emissivity as a function of Galactocentric radius does not show a large enhancement in the spiral arms with respect to the interarm region. The measured emissivity gradient is flatter that expectations based on a cosmic-ray propagation model using the radial distribution of supernova remnants and uniform diffusion properties. In this context, observations require a larger halo size and/or a flatter CR source distribution than usually assumed. The molecular mass calibrating ratio, X$sub CO$ …
Date: June 13, 2013
Creator: Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D. et al.
Object Type: Article
System: The UNT Digital Library
Design Concepts for the Cherenkov Telescope Array (open access)

Design Concepts for the Cherenkov Telescope Array

None
Date: June 13, 2013
Creator: Actis, M.; Agnetta, G.; Aharonian, F.; Akhperjanian, A.; Aleksic, J.; Aliu, E. et al.
Object Type: Article
System: The UNT Digital Library
Status of Plasma Electron Hose Instability Studies in FACET (open access)

Status of Plasma Electron Hose Instability Studies in FACET

In the FACET plasma-wakefield acceleration experiment a dense 23 GeV electron beam will interact with lithium and cesium plasmas, leading to plasma ion-channel formation. The interaction between the electron beam and the plasma sheath-electrons may lead to a fast growing electron hose instability. By using optics dispersion knobs to induce a controlled z-x tilt along the beam entering the plasma, we investigate the transverse behavior of the beam in the plasma as function of the tilt. We seek to quantify limits on the instability in order to further explore potential limitations on future plasma wakefield accelerators due to the electron hose instability. The FACET plasma-wakefield experiment at SLAC will study beam driven plasma wakefield acceleration. A dense 23 GeV electron beam will interact with lithium or cesium plasma, leading to plasma ion-channel formation. The interaction between the electron beam and the plasma sheath-electrons drives the electron hose instability, as first studied by Whittum. While Ref. [2] indicates the possibility of a large instability growth rate for typical beam and plasma parameters, other studies including have shown that several physical effects may mitigate the hosing growth rate substantially. So far there has been no quantitative benchmarking of experimentally observed hosing in …
Date: December 13, 2011
Creator: Adli, Erik; England, Robert Joel; Frederico, Joel; Hogan, Mark; Li, Selina Zhao; Litos, Michael Dennis et al.
Object Type: Article
System: The UNT Digital Library
Beam Dynamics Study of X-Band Linac Driven X-Ray FELS (open access)

Beam Dynamics Study of X-Band Linac Driven X-Ray FELS

Several linac driven X-ray Free Electron Lasers (XFELs) are being developed to provide high brightness photon beams with very short, tunable wavelengths. In this paper, three XFEL configurations are proposed that achieve LCLS-like performance using X-band linac drivers. These linacs are more versatile, efficient and compact than ones using S-band or C-band rf technology. For each of the designs, the overall accelerator layout and the shaping of the bunch longitudinal phase space are described briefly. During the last 40 years, the photon wavelengths from linac driven FELs have been pushed shorter by increasing the electron beam energy and adopting shorter period undulators. Recently, the wavelengths have reached the X-ray range, with FLASH (Free-Electron Laser in Hamburg) and LCLS (Linac Coherent Light Source) successfully providing users with soft and hard X-rays, respectively. FLASH uses a 1.2 GeV L-band (1.3 GHz) superconducting linac driver and can deliver 10-70 fs FWHM long photon pulses in a wavelength range of 44 nm to 4.1 nm. LCLS uses the last third of the SLAC 3 km S-band (2.856 GHz) normal-conducting linac to produce 3.5 GeV to 15 GeV bunches to generate soft and hard X-rays with good spatial coherence at wavelengths from 2.2 nm to …
Date: December 13, 2011
Creator: Adolphsen, C.; Limborg-Deprey, C.; Raubenheimer, T. O.; Wu, J. & Sun, Y.
Object Type: Article
System: The UNT Digital Library
LITERATURE REVIEW ON MAXIMUM LOADING OF RADIONUCLIDES ON CRYSTALLINE SILICOTITANATE (open access)

LITERATURE REVIEW ON MAXIMUM LOADING OF RADIONUCLIDES ON CRYSTALLINE SILICOTITANATE

Plans are underway to use small column ion exchange (SCIX) units installed in high-level waste tanks to remove Cs-137 from highly alkaline salt solutions at Savannah River Site. The ion exchange material slated for the SCIX project is engineered or granular crystalline silicotitanate (CST). Information on the maximum loading of radionuclides on CST is needed by Savannah River Remediation for safety evaluations. A literature review has been conducted that culminated in the estimation of the maximum loading of all but one of the radionuclides of interest (Cs-137, Sr-90, Ba-137m, Pu-238, Pu-239, Pu-240, Pu-241, Am-241, and Cm-244). No data was found for Cm-244.
Date: October 13, 2010
Creator: Adu-Wusu, K. & Pennebaker, F.
Object Type: Report
System: The UNT Digital Library
Overcoming Extreme-Scale Reproducibility Challenges Through a Unified, Targeted and Multilevel Toolset (open access)

Overcoming Extreme-Scale Reproducibility Challenges Through a Unified, Targeted and Multilevel Toolset

None
Date: August 13, 2013
Creator: Ahn, D H; Lee, G L; Gopalakrishnan, G; Rakamaric, Z; Schulz, M & Laguna, I
Object Type: Article
System: The UNT Digital Library
A Multi-TeV Linear Collider Based on CLIC Technology : CLIC Conceptual Design Report (open access)

A Multi-TeV Linear Collider Based on CLIC Technology : CLIC Conceptual Design Report

None
Date: February 13, 2014
Creator: Aicheler, M; Burrows, P.; Draper, M.; Garvey, T.; Lebrun, P.; Peach, K. et al.
Object Type: Report
System: The UNT Digital Library
Multi Optical Transition Radiation System for ATF2 (open access)

Multi Optical Transition Radiation System for ATF2

In this paper we describe the design, installation and first calibration tests of a Multi Optical Transition Radiation System in the beam diagnostic section of the Extraction (EXT) line of ATF2, close to the multi wire scanner system. This system will be a valuable tool for measuring beam sizes and emittances coming from the ATF Damping Ring. With an optical resolution of about 2 {micro}m an original OTR design (OTR1X) located after the septum at the entrance of the EXT line demonstrated the ability to measure a 5.5 {micro}m beam size in one beam pulse and to take many fast measurements. This gives the OTR the ability to measure the beam emittance with high statistics, giving a low error and a good understanding of emittance jitter. Furthermore the nearby wire scanners will be a definitive test of the OTR as a beam emittance diagnostic device. The multi-OTR system design proposed here is based on the existing OTR1X.
Date: July 13, 2012
Creator: Alabau-Gonzalvo, Javier; /Valencia U., IFIC; Blanch Gutierrez, Cesar; /Valencia U., IFIC; Civera, Jose Vicente; /Valencia U., IFIC et al.
Object Type: Article
System: The UNT Digital Library
Laser-Wakefield driven compact Compton scattering gamma-ray source (open access)

Laser-Wakefield driven compact Compton scattering gamma-ray source

None
Date: April 13, 2010
Creator: Albert, F.; Froula, D. H.; Hartemann, F. V. & Joshi, C.
Object Type: Report
System: The UNT Digital Library
QMDS: A File System Metadata Management Service Supporting a Graph Data Model-Based Query Language (open access)

QMDS: A File System Metadata Management Service Supporting a Graph Data Model-Based Query Language

Proposes QMDS: a file system metadata management service that integrates all file system metadata and uses a graph model with attributes on nodes and edges.
Date: September 13, 2010
Creator: Ames, S; Gokhale, M B & Maltzahn, C
Object Type: Article
System: The UNT Digital Library
Discharge Physics of High Power Impulse Magnetron Sputtering (open access)

Discharge Physics of High Power Impulse Magnetron Sputtering

High power impulse magnetron sputtering (HIPIMS) is pulsed sputtering where the peak power exceeds the time-averaged power by typically two orders of magnitude. The peak power density, averaged over the target area, can reach or exceed 107 W/m2, leading to plasma conditions that make ionization of the sputtered atoms very likely. A brief review of HIPIMS operation is given in a tutorial manner, illustrated by some original data related to the self-sputtering of niobium in argon and krypton. Emphasis is put on the current-voltage-time relationships near the threshold of self-sputtering runaway. The great variety of current pulse shapes delivers clues on the very strong gas rarefaction, self-sputtering runaway conditions, and the stopping of runaway due to the evolution of atom ionization and ion return probabilities as the gas plasma is replaced by metal plasma. The discussions are completed by considering instabilities and the special case of ?gasless? self-sputtering.
Date: October 13, 2010
Creator: Anders, Andre
Object Type: Article
System: The UNT Digital Library
Spin Crossover in Ferropericlase at High Pressure: A Seismically Hidden Transition? (open access)

Spin Crossover in Ferropericlase at High Pressure: A Seismically Hidden Transition?

None
Date: September 13, 2010
Creator: Antonangeli, Daniele; Siebert, Julien; Aracne, Chantel M.; Farber, Daniel L.; Bosak, A.; Hoesch, M. et al.
Object Type: Article
System: The UNT Digital Library
Mechanical design and analysis of an eight-pole superconducting vector magnet for soft x-ray magnetic dichroism measurements (open access)

Mechanical design and analysis of an eight-pole superconducting vector magnet for soft x-ray magnetic dichroism measurements

An eight-pole superconducting magnet is being developed for soft x-ray magnetic dichroism (XMD) experiments at the Advanced Light Source, Lawrence Berkley National Laboratory (LBNL). Eight conical Nb{sub 3}Sn coils with Holmium poles are arranged in octahedral symmetry to form four dipole pairs that provide magnetic fields of up to 5 T in any direction relative to the incoming x-ray beam. The dimensions of the magnet yoke as well as pole taper, diameter, and length were optimized for maximum peak field in the magnet center using the software package TOSCA. The structural analysis of the magnet is performed using ANSYS with the coil properties derived using a numerical homogenization scheme. It is found that the use of orthotropic material properties for the coil has an important influence in the design of the magnet.
Date: January 13, 2010
Creator: Arbelaez, D.; Black, A.; Prestemon, S.O.; Wang, S.; Chen, J. & Arenholz, E.
Object Type: Article
System: The UNT Digital Library
HEAVY WATER COMPONENTS TEST REACTOR DECOMMISSIONING (open access)

HEAVY WATER COMPONENTS TEST REACTOR DECOMMISSIONING

The Heavy Water Components Test Reactor (HWCTR) Decommissioning Project was initiated in 2009 as a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Removal Action with funding from the American Recovery and Reinvestment Act (ARRA). This paper summarizes the history prior to 2009, the major D&D activities, and final end state of the facility at completion of decommissioning in June 2011. The HWCTR facility was built in 1961, operated from 1962 to 1964, and is located in the northwest quadrant of the Savannah River Site (SRS) approximately three miles from the site boundary. The HWCTR was a pressurized heavy water test reactor used to develop candidate fuel designs for heavy water power reactors. In December of 1964, operations were terminated and the facility was placed in a standby condition as a result of the decision by the U.S. Atomic Energy Commission to redirect research and development work on heavy water power reactors to reactors cooled with organic materials. For about one year, site personnel maintained the facility in a standby status, and then retired the reactor in place. In the early 1990s, DOE began planning to decommission HWCTR. Yet, in the face of new budget constraints, DOE deferred dismantlement and …
Date: October 13, 2011
Creator: Austin, W. & Brinkley, D.
Object Type: Article
System: The UNT Digital Library
Argonne's Laboratory Computing Resource Center 2009 Annual Report. (open access)

Argonne's Laboratory Computing Resource Center 2009 Annual Report.

Now in its seventh year of operation, the Laboratory Computing Resource Center (LCRC) continues to be an integral component of science and engineering research at Argonne, supporting a diverse portfolio of projects for the U.S. Department of Energy and other sponsors. The LCRC's ongoing mission is to enable and promote computational science and engineering across the Laboratory, primarily by operating computing facilities and supporting high-performance computing application use and development. This report describes scientific activities carried out with LCRC resources in 2009 and the broad impact on programs across the Laboratory. The LCRC computing facility, Jazz, is available to the entire Laboratory community. In addition, the LCRC staff provides training in high-performance computing and guidance on application usage, code porting, and algorithm development. All Argonne personnel and collaborators are encouraged to take advantage of this computing resource and to provide input into the vision and plans for computing and computational analysis at Argonne. The LCRC Allocations Committee makes decisions on individual project allocations for Jazz. Committee members are appointed by the Associate Laboratory Directors and span a range of computational disciplines. The 350-node LCRC cluster, Jazz, began production service in April 2003 and has been a research work horse ever …
Date: May 13, 2011
Creator: Bair, R. B. (CLS-CI)
Object Type: Report
System: The UNT Digital Library
Final report - Reduction of mercury in saturated subsurface sediments and its potential to mobilize mercury in its elemental form (open access)

Final report - Reduction of mercury in saturated subsurface sediments and its potential to mobilize mercury in its elemental form

The goal of our project was to investigate Hg(II) reduction in the deep subsurface. We focused on microbial and abiotic pathways of reduction and explored how it affected the toxicity and mobility of Hg in this unique environment. The project’s tasks included: 1. Examining the role of mer activities in the reduction of Hg(II) in denitrifying enrichment cultures; 2. Investigating the biotic/abiotic reduction of Hg(II) under iron reducing conditions; 3. Examining Hg(II) redox transformations under anaerobic conditions in subsurface sediments from DOE sites.
Date: June 13, 2013
Creator: Bakray, Tamar
Object Type: Report
System: The UNT Digital Library