Linear and chromatic optics measurements at RHIC (open access)

Linear and chromatic optics measurements at RHIC

Measurements of chromatic beta-beating were carried out for the first time in the RHIC accelerator during Run 2009. The analysis package developed for the LHC was used to extract the off-momentum optics for injection and top energy. Results from the beam experiments and compassion to the optics model are presented. The primary goal of the RHIC experiments were execute an on-line measurement of the optics using the tools developed for the LHC. Turn-by-turn BPM trajectories (typically 1000 turns) acquired immediately after an external dipole kick are numerically analyzed to determine the optical parameters at the location of the beam position monitors (BPMs). For chromatic optics, a similar analysis, but on a beam with finite momentum offset(s). Each optical measurement typically is calculated from multiple data sets to capture statistical variations and ensure reproducibility. The procedure of measurement and analysis is detailed in ref [1, 2]. Two dedicated experiments were performed at RHIC with protons during Run 2009. The first at injection energy and optics and the other at 250 GeV and squeezed optics. The basic RHIC parameters relevant for the two experiments are listed in Table 1.
Date: May 23, 2010
Creator: Aiba, M.; Calaga, R.; Aiba, M.; Tomas, R. & Vanbavinkove, G.
Object Type: Article
System: The UNT Digital Library
Offshore Wind Turbines - Estimated Noise from Offshore Wind Turbine, Monhegan Island, Maine: Environmental Effects of Offshore Wind Energy Development (open access)

Offshore Wind Turbines - Estimated Noise from Offshore Wind Turbine, Monhegan Island, Maine: Environmental Effects of Offshore Wind Energy Development

Deep C Wind, a consortium headed by the University of Maine will test the first U.S. offshore wind platforms in 2012. In advance of final siting and permitting of the test turbines off Monhegan Island, residents of the island off Maine require reassurance that the noise levels from the test turbines will not disturb them. Pacific Northwest National Laboratory, at the request of the University of Maine, and with the support of the U.S. Department of Energy Wind Program, modeled the acoustic output of the planned test turbines.
Date: November 23, 2010
Creator: Aker, Pamela M.; Jones, Anthony M. & Copping, Andrea E.
Object Type: Report
System: The UNT Digital Library
Electron Cloud at Low Emittance in CesrTA (open access)

Electron Cloud at Low Emittance in CesrTA

The Cornell Electron Storage Ring (CESR) has been reconfigured as a test accelerator (CesrTA) for a program of electron cloud (EC) research at ultra low emittance. The instrumentation in the ring has been upgraded with local diagnostics for measurement of cloud density and with improved beam diagnostics for the characterization of both the low emittance performance and the beam dynamics of high intensity bunch trains interacting with the cloud. A range of EC mitigation methods have been deployed and tested and their effectiveness is discussed. Measurements of the electron cloud's effect on the beam under a range of conditions are discussed along with the simulations being used to quantitatively understand these results.
Date: May 23, 2010
Creator: Alexander, J. P.; Billing, M. G.; Calvey, J.; Crittenden, J. A.; Dugan, G.; Eggert, N. et al.
Object Type: Article
System: The UNT Digital Library
Atomic-level cotrol of the thermoelectric properties in polytypoid nanowires (open access)

Atomic-level cotrol of the thermoelectric properties in polytypoid nanowires

Thermoelectric materials have generated interest as a means of increasing the efficiency of power generation through the scavenging of waste heat. Materials containing nanometer-sized structural and compositional features can exhibit enhanced thermoelectric performance due to the decoupling of certain electrical and thermal properties, but the extent to which these features can be controlled is often limited. Here we report a simple synthesis of M{sub 2}O{sub 3}(ZnO){sub n} (M = In, Ga, Fe) nanowires with controllable polytypoid structures, where the nanostructured features are tuned by adjusting the amount of metal precursor. After the introduction of nanometer-scale features (individual atomic layers and alloying), thermal and electrical measurements on single In{sub 2-x}Ga{sub x}O3(ZnO){sub n} nanowires reveal a simultaneous improvement in all contributing factors to the thermoelectric figure of merit, indicating successful modification of the nanowire transport properties.
Date: October 23, 2010
Creator: Andrews, Sean C.; Fardy, Melissa A.; Moore, Michael C.; Aloni, Shaoul; Zhang, Minjuan; Radmilovic, Velimir et al.
Object Type: Article
System: The UNT Digital Library
Guinea's New Transitional Government: Emerging Issues for U.S. Policy (open access)

Guinea's New Transitional Government: Emerging Issues for U.S. Policy

This report provides background information on the government of national unity of Guinea. The report discusses issues for U.S. policy and bilateral relations with the transitional government.
Date: April 23, 2010
Creator: Arieff, Alexis
Object Type: Report
System: The UNT Digital Library
Observation of off-Hugoniot shocked states with ultrafast time resolution (open access)

Observation of off-Hugoniot shocked states with ultrafast time resolution

We apply ultrafast single shot interferometry to determine the pressure and density of argon shocked from up to 7.8 GPa static initial pressure in a diamond anvil cell. This method enables the observation of thermodynamic states distinct from those observed in either single shock or isothermal compression experiments, and the observation of ultrafast dynamics in shocked materials. We also present a straightforward method for interpreting ultrafast shock wave data which determines the index of refraction at the shock front, and the particle and shock velocities for shock waves in transparent materials. Based on these methods, we observe shocked thermodynamic states between the room temperature isotherm of argon and the shock adiabat of cryogenic argon at final shock pressures up to 28 GPa.
Date: February 23, 2010
Creator: Armstrong, M; Crowhurst, J; Bastea, S & Zaug, J
Object Type: Article
System: The UNT Digital Library
TUNING SILICON NANORODS FOR ANODES OF LI-ION RECHARGEABLE BATTERIES (open access)

TUNING SILICON NANORODS FOR ANODES OF LI-ION RECHARGEABLE BATTERIES

Silicon is a promising anode material for Li-ion batteries in regarding of high capacity, low cost and safety, but it suffers poor cycling stability due to the pulverization induced by severe volume expansion/shrinkage (297%) during lithium insertion/extraction. In our previous investigation on aluminum nanorods anodes, it is found the selection of substrates in which Al nanorods grown plays the role in prevention of pulverization resulting in the increase of cycling life. Adapting this knowledge, we investigated the Si based nanorods anodes by tuning its composition and element distribution. Our results show that although the Si nanorods demonstrated higher initial anodic capacity of 1500 mAh/g, it diminished after 50 cycles due to morphology change and pulverization. By codepositing Cu, the Si-Cu composite nanorods demonstrated sustainable capacity of 500 mAh/g in 100 cycles attributing to its flexible and less brittle nature.
Date: November 23, 2010
Creator: Au, M.
Object Type: Article
System: The UNT Digital Library
Novel Geometries for the LHC Crab Cavity (open access)

Novel Geometries for the LHC Crab Cavity

The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the IP necessitates a more compact design than is possible with elliptical cavities such as those used at KEK. The reduction in size must be achieved without an increase in the operational frequency to maintain compatibility with the long bunch length of the LHC. This paper proposes a suitable superconducting variant of a four rod coaxial deflecting cavity (to be phased as a crab cavity), and presents analytical models and simulations of suitable designs.
Date: May 23, 2010
Creator: B. Hall, G. Burt, C. Lingwood, R. Rimmer, H. Wang
Object Type: Article
System: The UNT Digital Library
RHIC Spin Flipper Commissioning Status (open access)

RHIC Spin Flipper Commissioning Status

The commissioning of the RHIC spin flipper in the RHIC Blue ring during the RHIC polarized proton run in 2009 showed the detrimental effects of global vertical coherent betatron oscillation induced by the 2-AC dipole plus 4-DC dipole configuration. This global orbital coherent oscillation of the RHIC beam in the Blue ring in the presence of collision modulated the beam-beam interaction between the two RHIC beams and affected Yellow beam polarization. The experimental data at injection with different spin tunes by changing the snake current also demonstrated that it was not possible to induce a single isolated spin resonance with the global vertical coherent betatron oscillation excited by the two AC dipoles. Hence, a new design was proposed to eliminate the coherent vertical betatron oscillation outside the spin flipper by adding three additional AC dipoles. This paper presents the experimental results as well as the new design.
Date: May 23, 2010
Creator: Bai, M.; Meot, F.; Dawson, C.; Oddo, P.; Pai, C.; Pile, P. et al.
Object Type: Article
System: The UNT Digital Library
Political Status of Puerto Rico: Options for Congress (open access)

Political Status of Puerto Rico: Options for Congress

This report discusses the current U.S.-Puerto Rico relationship, the history of said relationship, and the current political state of Puerto Rico, as well as relevant pieces of U.S. Congressional legislation concerning Puerto Rico.
Date: April 23, 2010
Creator: Bea, Keith & Garrett, R. Sam
Object Type: Report
System: The UNT Digital Library
2009 ALCF annual report. (open access)

2009 ALCF annual report.

This year the Argonne Leadership Computing Facility (ALCF) delivered nearly 900 million core hours of science. The research conducted at their leadership class facility touched our lives in both minute and massive ways - whether it was studying the catalytic properties of gold nanoparticles, predicting protein structures, or unearthing the secrets of exploding stars. The authors remained true to their vision to act as the forefront computational center in extending science frontiers by solving pressing problems for our nation. Our success in this endeavor was due mainly to the Department of Energy's (DOE) INCITE (Innovative and Novel Computational Impact on Theory and Experiment) program. The program awards significant amounts of computing time to computationally intensive, unclassified research projects that can make high-impact scientific advances. This year, DOE allocated 400 million hours of time to 28 research projects at the ALCF. Scientists from around the world conducted the research, representing such esteemed institutions as the Princeton Plasma Physics Laboratory, National Institute of Standards and Technology, and European Center for Research and Advanced Training in Scientific Computation. Argonne also provided Director's Discretionary allocations for research challenges, addressing such issues as reducing aerodynamic noise, critical for next-generation 'green' energy systems. Intrepid - the …
Date: November 23, 2010
Creator: Beckman, P.; Martin, D. & Drugan, C.
Object Type: Report
System: The UNT Digital Library
Colombia: Issues for Congress (open access)

Colombia: Issues for Congress

This report provides an overview of recent political developments in Colombia, including the administration of President Uribe (2002-2010), continuing into the election of President Juan Manuel Santos. It discusses the political issues including Colombia's longstanding conflict with internal armed groups and ongoing challenges such as human rights, demobilization and displacement, drug trends, and Colombia's regional relations. The report also lays out issues for Congress including various plans for addressing those issues.
Date: April 23, 2010
Creator: Beittel, June S.
Object Type: Report
System: The UNT Digital Library
Beam break-up estimates for the ERL at BNL (open access)

Beam break-up estimates for the ERL at BNL

A prototype Ampere-class superconducting energy recovery linac (ERL) is under advanced construction at BNL. The ERL facility is comprised of a five-cell SC Linac plus a half-cell SC photo-injector RF electron gun, both operating at 703.75 MHz. The facility is designed for either a high-current mode of operation up to 0.5 A at 703.75 MHz or a high-bunch-charge mode of 5 nC at 10 MHz bunch frequency. The R&D facility serves a test bed for an envisioned electron-hadron collider, eRHIC. The high-current, high-charge operating parameters make effective higher-order-mode (HOM) damping mandatory, and requires the determination of HOM tolerances for a cavity upgrade. The niobium cavity has been tested at superconducting temperatures and has provided measured quality factors (Q) for a large number of modes. These numbers were used for the estimate of the beam breakup instability (BBU). The facility will be assembled with a highly flexible lattice covering a vast operational parameter space for verification of the estimates and to serve as a test bed for the concepts directed at future projects.
Date: May 23, 2010
Creator: Ben-Zvi, Ilan; Calaga, R.; Hahn, H.; Hammons, L.; Johnson, E.; Kayran, D. et al.
Object Type: Article
System: The UNT Digital Library
Organized Crime: An Evolving Challenge for U.S. Law Enforcement (open access)

Organized Crime: An Evolving Challenge for U.S. Law Enforcement

This report provides an analysis of how organized crime has capitalized on globalization by using borders as opportunities, relying on fast-paced technological change, and adapting its organizational structures. It illustrates how these transformations can impact U.S. persons, businesses, and interests. The report includes a discussion of how U.S. law enforcement conceptualizes organized crime in the 21st century and concludes by examining potential issues for Congress, including the extent to which organized crime is a national security threat (partly to be tackled by U.S. law enforcement agencies), congressional oversight regarding the federal coordination of organized crime investigations, and the utility of current resources appropriated to combat organized crime.
Date: December 23, 2010
Creator: Bjelopera, Jerome P. & Finklea, Kristin M.
Object Type: Report
System: The UNT Digital Library
The Millennium Development Goals: The September 2010 U.N. High-level Meeting (open access)

The Millennium Development Goals: The September 2010 U.N. High-level Meeting

This report discusses overarching trends in Millennium Development Goals (MDG) progress and lessons learned from previous and ongoing efforts to achieve them. The MDGs are a group of measurable development targets agreed to by 189 U.N. member states - including the United States - as part of the 2000 Millennium Declaration. The MDGs cover a number of issues, such as eradicating extreme hunger and poverty, combating HIV/AIDS, and promoting gender equality and women's empowerment. This report examines U.S. policy toward the MDGs and how, if at all, the Goals fit into U.S. development and foreign assistance policy. It also examines different schools of thought regarding the effectiveness of the Goals, their role in international development, and their long-term sustainability. This report addresses the MDGs as a whole; it does not assess or analyze issues pertaining to the individual Goals.
Date: September 23, 2010
Creator: Blanchfield, Luisa & Lawson, Marian Leonardo
Object Type: Report
System: The UNT Digital Library
Test of the Universality of Naive-time-reversal-odd Fragmentation Functions (open access)

Test of the Universality of Naive-time-reversal-odd Fragmentation Functions

We investigate the"spontaneous'' hyperon transverse polarization in e+e- annihilation and semi-inclusive deep inelastic scattering processes as a test of the universality of the naive-time-reversal-odd transverse momentum dependent fragmentation functions. We find that universality implies definite sign relations among various observables. This provides a unique opportunity to study initial/final state interaction effects in the fragmentation process and test the associated factorization.
Date: August 23, 2010
Creator: Boer, Daniel; Kang, Zhong-Bo; Vogelsang, Werner & Yuan, Feng
Object Type: Article
System: The UNT Digital Library
Plasmon resonant cavities in vertical nanowire arrays (open access)

Plasmon resonant cavities in vertical nanowire arrays

We investigate tunable plasmon resonant cavity arrays in paired parallel nanowire waveguides. Resonances are observed when the waveguide length is an odd multiple of quarter plasmon wavelengths, consistent with boundary conditions of node and antinode at the ends. Two nanowire waveguides satisfy the dispersion relation of a planar metal-dielectric-metal waveguide of equivalent width equal to the square field average weighted gap. Confinement factors over 103 are possible due to plasmon focusing in the inter-wire space.
Date: February 23, 2010
Creator: Bora, Mihail; Fasenfest, Benjamin J.; Behymer, Elaine M.; Chang, Allan S-P & Bond, Tiziana C.
Object Type: Article
System: The UNT Digital Library
AutomaDeD: Automata-Based Debugging for Dissimilar Parallel Tasks (open access)

AutomaDeD: Automata-Based Debugging for Dissimilar Parallel Tasks

Today's largest systems have over 100,000 cores, with million-core systems expected over the next few years. This growing scale makes debugging the applications that run on them a daunting challenge. Few debugging tools perform well at this scale and most provide an overload of information about the entire job. Developers need tools that quickly direct them to the root cause of the problem. This paper presents AutomaDeD, a tool that identifies which tasks of a large-scale application first manifest a bug at a specific code region at a specific point during program execution. AutomaDeD creates a statistical model of the application's control-flow and timing behavior that organizes tasks into groups and identifies deviations from normal execution, thus significantly reducing debugging effort. In addition to a case study in which AutomaDeD locates a bug that occurred during development of MVAPICH, we evaluate AutomaDeD on a range of bugs injected into the NAS parallel benchmarks. Our results demonstrate that detects the time period when a bug first manifested itself with 90% accuracy for stalls and hangs and 70% accuracy for interference faults. It identifies the subset of processes first affected by the fault with 80% accuracy and 70% accuracy, respectively and the …
Date: March 23, 2010
Creator: Bronevetsky, G; Laguna, I; Bagchi, S; de Supinski, B R; Ahn, D & Schulz, M
Object Type: Article
System: The UNT Digital Library
Statistical Fault Detection for Parallel Applications with AutomaDeD (open access)

Statistical Fault Detection for Parallel Applications with AutomaDeD

Today's largest systems have over 100,000 cores, with million-core systems expected over the next few years. The large component count means that these systems fail frequently and often in very complex ways, making them difficult to use and maintain. While prior work on fault detection and diagnosis has focused on faults that significantly reduce system functionality, the wide variety of failure modes in modern systems makes them likely to fail in complex ways that impair system performance but are difficult to detect and diagnose. This paper presents AutomaDeD, a statistical tool that models the timing behavior of each application task and tracks its behavior to identify any abnormalities. If any are observed, AutomaDeD can immediately detect them and report to the system administrator the task where the problem began. This identification of the fault's initial manifestation can provide administrators with valuable insight into the fault's root causes, making it significantly easier and cheaper for them to understand and repair it. Our experimental evaluation shows that AutomaDeD detects a wide range of faults immediately after they occur 80% of the time, with a low false-positive rate. Further, it identifies weaknesses of the current approach that motivate future research.
Date: March 23, 2010
Creator: Bronevetsky, G; Laguna, I; Bagchi, S; de Supinski, B R; Ahn, D & Schulz, M
Object Type: Article
System: The UNT Digital Library
The Wild and Scenic Rivers Act (WSRA): Protections, Federal Water Rights, and Development Restrictions (open access)

The Wild and Scenic Rivers Act (WSRA): Protections, Federal Water Rights, and Development Restrictions

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Date: February 23, 2010
Creator: Brougher, Cynthia
Object Type: Report
System: The UNT Digital Library
RHIC Performance During the FY10 200 GeV Au+Au Heavy Ion Run (open access)

RHIC Performance During the FY10 200 GeV Au+Au Heavy Ion Run

Since the last successful RHIC Au+Au run in 2007 (Run-7), the RHIC experiments have made numerous detector improvements and upgrades. In order to benefit from the enhanced detector capabilities and to increase the yield of rare events in the acquired heavy ion data a significant increase in luminosity is essential. In Run-7 RHIC achieved an average store luminosity of <L> = 12 x 10{sup 26} cm{sup -2} s{sup -1} by operating with 103 bunches (out of 111 possible), and by squeezing to {beta}* = 0.85 m. This year, Run-10, we achieved <L> = 20 x 10{sup 26} cm{sup -2} s{sup -1}, which put us an order of magnitude above the RHIC design luminosity. To reach these luminosity levels we decreased {beta}* to 0.75 m, operated with 111 bunches per ring, and reduced longitudinal and transverse emittances by means of bunched-beam stochastic cooling. In addition we introduced a lattice to suppress intra-beam scattering (IBS) in both RHIC rings, upgraded the RF control system, and separated transition crossing times in the two rings. We present an overview of the changes and the results of Run-10 performance.
Date: May 23, 2010
Creator: Brown, K. A.; Ahrens, L.; Bai, M.; Beebe-Wang, J.; Blaskiewicz, M.; Brennan, J. et al.
Object Type: Article
System: The UNT Digital Library
Characterization of Glass-Like Fragments from the 3714 Building (open access)

Characterization of Glass-Like Fragments from the 3714 Building

This report describes characterization of a sample obtained from the 3714 building in the 300 Area. Characterization of this unknown material was required for the demonolition activities in the 300 Area. The object of the study was to dertermine the nature of the material, composition, possible structure, evidence for hazards components. The green material is a sodium alumino-silicate glass. This conclusion is based on the composition provided by SEM-EDS, and the images that suggest a glass-like morphology. Further analysis with Ramin and/or infrared could be used to determine the presence of any organics.
Date: February 23, 2010
Creator: Buck, Edgar C.
Object Type: Report
System: The UNT Digital Library
The Endangered Species Act (ESA) in the 111th Congress: Conflicting Values and Difficult Choices (open access)

The Endangered Species Act (ESA) in the 111th Congress: Conflicting Values and Difficult Choices

The Endangered Species Act has been one of the more contentious environmental laws. This may stem from its strict substantive provisions, which can affect the use of both federal and nonfederal lands and resources. This report discusses oversight issues and legislation introduced in the 11th Congress to address Endangered Species Act implementation and management of endangered and threatened species.
Date: April 23, 2010
Creator: Buck, Eugene H.; Corn, M. Lynne; Sheikh, Pervaze A.; Meltz, Robert & Alexander, Kristina
Object Type: Report
System: The UNT Digital Library
G-Band Vapor Radiometer Profiler (GVRP) Handbook (open access)

G-Band Vapor Radiometer Profiler (GVRP) Handbook

The G-Band Vapor Radiometer Profiler (GVRP) provides time-series measurements of brightness temperatures from 15 channels between 170 and 183.310 GHz. Atmospheric emission in this spectral region is primarily due to water vapor, with some influence from liquid water. Channels between 170.0 and 176.0 GHz are particularly sensitive to the presence of liquid water. The sensitivity to water vapor of the 183.31-GHz line is approximately 30 times higher than at the frequencies of the two-channel microwave radiometer (MWR) for a precipitable water vapor (PWV) amount of less than 2.5 mm. Measurements from the GVRP instrument are therefore especially useful during low-humidity conditions (PWV < 5 mm). In addition to integrated water vapor and liquid water, the GVRP can provide low-resolution vertical profiles of water vapor in very dry conditions.
Date: June 23, 2010
Creator: Caddeau, M. P.
Object Type: Report
System: The UNT Digital Library