Setup and performance of RHIC for the 2008 run with deuteron-gold collisions. (open access)

Setup and performance of RHIC for the 2008 run with deuteron-gold collisions.

This year (2008) deuterons and gold ions were collided in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) for the first time since 2003. The setup and performance of the collider for the 2008 run is reviewed with a focus on improvements that have led to an order of magnitude increase in luminosity over that achieved in the 2003 run.
Date: June 23, 2008
Creator: Gardner,C.; Abreu, N.P.; Ahren, L.; Alessi, J.; Bai, M. & al., et
Object Type: Article
System: The UNT Digital Library
Fabrication of Cryogenic Manganite Bolometers to Measure the Total Energy at the LCLS Free Electron X-ray Laser (open access)

Fabrication of Cryogenic Manganite Bolometers to Measure the Total Energy at the LCLS Free Electron X-ray Laser

We are developing cryogenic bolometers to measure the total energy of the Linac Coherent Light Source (LCLS) free electron X-ray laser that is currently being built at the Stanford Linear Accelerator Center. LCLS will produce ultrashort {approx}200 fs X-ray laser pulses with {approx}10{sup 13} photons at 0.8 keV up to {approx}10{sup 12} photons at 8 keV per pulse at a repeat interval as short as 8 ms, and will be accompanied by a halo of spontaneous undulator radiation. Our bolometer consists of a 375 {micro}m thick Si absorber and a Nd{sub 0.67}Sr{sub 0.33}MnO{sub 3} sensor operated at its metal-insulator transition. It will measure the total energy of each pulse with a precision of <1%, and is designed to meet the conflicting requirements of radiation hardness, sensitivity, linearity over a dynamic range of three orders of magnitude, and readout speed compatible with the LCLS pulse rate. Here we discuss bolometer design and fabrication, and the photoresponse of prototype devices to pulsed optical lasers.
Date: June 14, 2008
Creator: Drury, O B; Yong, G J; Kolagani, R M; Liang, Y; Gardner, C; Ables, E et al.
Object Type: Article
System: The UNT Digital Library
AGS polarized proton operation in run 8. (open access)

AGS polarized proton operation in run 8.

Dual partial snake scheme has been used for the Brookhaven AGS (Alternating Gradient Synchrotron) polarized proton operation for several years. It has provided polarized proton beams with 1.5 x 10{sup 11} intensity and 65% polarization for RHIC spin program. There is still residual polarization loss. Several schemes such as putting horizontal tune into the spin tune gap, and injection-on-the-fly were tested in the AGS to mitigate the loss. This paper presents the experiment results and analysis.
Date: June 23, 2008
Creator: Huang, H.; Ahrens, L.; Bai, M.; Brown, K. A.; Gardner, C.; Glenn, J. W. et al.
Object Type: Article
System: The UNT Digital Library
Injection and Acceleration of Au31+ in the BNL AGS. (open access)

Injection and Acceleration of Au31+ in the BNL AGS.

Injection and acceleration of ions in a lower charge state reduces space charge effects, and, if further elcctron stripping is needed, may allow elimination of a stripping stage and the associated beam losses. The former is of interest to the accelerators in the GSI FAIR complex, the latter for BNL RHIC collider operation at energies lower than the current injection energy. Lower charge state ions, however, have a higher likelihood of electron stripping which can lead to dynamic pressures rises and subsequent beam losses. We report on experiments in the AGS where Au{sup 31+} ions were injected and accelerated instead of the normally used Au{sup 77+} ions. Beam intensities and the average pressure in the AGS ring are recorded, and compared with calculations for dynamic pressures and beam losses. The experimental results will be used to benchmark the StrahlSim dynamic vacuum code and will be incorporated in the GSI FAIR SIS100 design.
Date: June 23, 2008
Creator: Fischer, W.; Ahrens, L.; Brown, K.; Gardner, C.; Glenn, W.; Huang, H. et al.
Object Type: Article
System: The UNT Digital Library
Final Report PetaScale Application Development Analysis Grant Number DE-FG02-04ER25629 (open access)

Final Report PetaScale Application Development Analysis Grant Number DE-FG02-04ER25629

The results obtained from this project will fundamentally change the way we look at computer performance analysis. These results are made possible by the precise definition of a consistent system of measurement with a set of primary units designed specifically for computer performance analysis. This system of units, along with their associated dimensions, allows us to apply the methods of dimensional analysis, based on the Pi Theorem, to define scaling and self-similarity relationships. These relationships reveal new insights into experimental results that otherwise seems only vaguely correlated. Applying the method to cache-miss data revealed scaling relationships that were not seen by those who originally collected the data. Applying dimensional analysis to the performance of parallel numerical algorithms revealed that computational force is a unifying concept for understanding the interaction between hardware and software. The efficiency of these algorithms depends, in a very intimate way, on the balance between hardware forces and software forces. Analysis of five different algorithms showed that performance analysis can be reduced to a study of the differential geometry of the efficiency surface. Each algorithm defines a set of curvilinear coordinates, specific to that algorithm, and different machines follow different paths along the surface depending on the …
Date: June 20, 2008
Creator: Numrich, Robert W.
Object Type: Report
System: The UNT Digital Library
VERTIGO (VERtical Transport In the Global Ocean): A study of particle sources and flux attenuation in the North Pacific (open access)

VERTIGO (VERtical Transport In the Global Ocean): A study of particle sources and flux attenuation in the North Pacific

The VERtical Transport In the Global Ocean (VERTIGO) study examined particle sources and fluxes through the ocean's 'twilight zone' (defined here as depths below the euphotic zone to 1000 m). Interdisciplinary process studies were conducted at contrasting sites off Hawaii (ALOHA) and in the NW Pacific (K2) during 3 week occupations in 2004 and 2005, respectively. We examine in this overview paper the contrasting physical, chemical and biological settings and how these conditions impact the source characteristics of the sinking material and the transport efficiency through the twilight zone. A major finding in VERTIGO is the considerably lower transfer efficiency (T{sub eff}) of particulate organic carbon (POC), POC flux 500/150 m, at ALOHA (20%) vs. K2 (50%). This efficiency is higher in the diatom-dominated setting at K2 where silica-rich particles dominate the flux at the end of a diatom bloom, and where zooplankton and their pellets are larger. At K2, the drawdown of macronutrients is used to assess export and suggests that shallow remineralization above our 150 m trap is significant, especially for N relative to Si. We explore here also surface export ratios (POC flux/primary production) and possible reasons why this ratio is higher at K2, especially during the …
Date: June 10, 2008
Creator: Buesseler, K. O.; Trull, T. W.; Steinberg, D. K.; Silver, M. W.; Siegel, D. A.; Saitoh, S. I. et al.
Object Type: Article
System: The UNT Digital Library
Long-Term Monitoring at the East and West Flower Garden Banks, 2004-2005 -- Interim Report, Volume 1: Technical Report (open access)

Long-Term Monitoring at the East and West Flower Garden Banks, 2004-2005 -- Interim Report, Volume 1: Technical Report

A report documenting the monitoring of the East and West Flower Garden Banks in accordance with the long-term monitoring protocol.
Date: June 2008
Creator: Precht, William F.; Aronson, Richard B.; Deslarzes, Kenneth J. P.; Robbart, Martha L.; Evans, David J.; Zimmer, Beth et al.
Object Type: Text
System: The UNT Digital Library
Analysis of intensity instability threshold at transition in RHIC. (open access)

Analysis of intensity instability threshold at transition in RHIC.

The beam intensity of ion beams in RHIC is limited by a fast transverse instability at transition, driven by the machine impedance and electron clouds. For gold and deuteron beams we analyze the dependence of the instability threshold on beam and machine parameters from recent operational data and dedicated experiments. We fit the machine impedance to the experimental data.
Date: June 23, 2008
Creator: Fischer, W.; Blaskiewicz, M.; Cameron, P.; Montag, C. & Ptitsyn, V.
Object Type: Article
System: The UNT Digital Library
Joint Groundwater Monitoring and Contamination Report: 2007 (open access)

Joint Groundwater Monitoring and Contamination Report: 2007

Annual report compiling information about required groundwater monitoring activities and cases of contamination by state-regulated activities during the YYYY calendar year. Includes tables with the enforcement status of each case of contamination.
Date: June 2008
Creator: Texas Groundwater Protection Committee
Object Type: Report
System: The Portal to Texas History
RHIC polarized proton performance in run-8. (open access)

RHIC polarized proton performance in run-8.

During Run-8, the Relativistic Heavy Ion Collider (RHIC) provided collisions of spin-polarized proton beams at two interaction regions. Helical spin rotators at these two interaction regions were used to control the spin orientation of both beams at the collision points. Physics data were taken with different orientations of the beam polarization. We present recent developments and improvements as well as the luminosity and polarization performance achieved during Run-8.
Date: June 23, 2008
Creator: Montag, C.; Abreu, N.; Ahrens, L.; Bai, M.; Barton, D. & al., et
Object Type: Article
System: The UNT Digital Library
Presidential Appointments to Full-time Positions in Executive Departments During the 109th Congress, 2005-2006 (open access)

Presidential Appointments to Full-time Positions in Executive Departments During the 109th Congress, 2005-2006

This report provides an overview of the process for filling positions to which the President makes appointments with the advice and consent of the Senate (PAS positions). It also identifies, for the 109th Congress, all nominations to executive level full-time positions in the 15 departments. Profiles of the departments provide basic information regarding their full-time PAS positions and related appointment activity during the 109th Congress.
Date: June 10, 2008
Creator: Hogue, Henry B.; Bearden, Maureen & Ely, Dana
Object Type: Report
System: The UNT Digital Library
Experimental Investigation of Material Flows Within FSWs Using 3D Tomography (open access)

Experimental Investigation of Material Flows Within FSWs Using 3D Tomography

There exists significant prior work using tracers or pre-placed hardened markers within friction stir welding (FSWing) to experimentally explore material flow within the FSW process. Our experiments replaced markers with a thin sheet of copper foil placed between the 6061 aluminum lap and butt joints that were then welded. The absorption characteristics of x-rays for copper and aluminum are significantly different allowing for non-destructive evaluation (NDE) methods such as x-ray computed tomography (CT) to be used to demonstrate the material movement within the weldment on a much larger scale than previously shown. 3D CT reconstruction of the copper components of the weldment allows for a unique view into the final turbulent state of the welding process as process parameters are varied. The x-ray CT data of a section of the weld region was collected using a cone-beam x-ray imaging system developed at the INL. Six-hundred projections were collected over 360-degrees using a 160-kVp Bremsstrahlung x-ray generator (25-micrometer focal spot) and amorphoussilicon x-ray detector. The region of the object that was imaged was about 3cm tall and 1.5cm x 1cm in cross section, and was imaged at a magnification of about 3.6x. The data were reconstructed on a 0.5x0.5x0.5 mm3 voxel …
Date: June 1, 2008
Creator: Tolle, Charles R.; White, Timothy A.; Miller, Karen S.; Clark, Denis E. & Smartt, Herschel B.
Object Type: Article
System: The UNT Digital Library
RHIC and its upgrade programmes. (open access)

RHIC and its upgrade programmes.

As the first hadron accelerator and collider consisting of two independent superconducting rings RHIC has operated with a wide range of beam energies and particle species. After a brief review of the achieved performance the presentation will give an overview of the plans, challenges and status of machine upgrades, that range from a new heavy ion pre-injector and beam cooling at 100 GeV to a high luminosity electron-ion collider.
Date: June 23, 2008
Creator: Roser, T.
Object Type: Article
System: The UNT Digital Library
Survey of Collective Instabilities and Beam-Plasma Interactions in Intense Heavy Ion Beams (open access)

Survey of Collective Instabilities and Beam-Plasma Interactions in Intense Heavy Ion Beams

This paper presents a survey of the present theoretical understanding based on advanced analytical and numerical studies of collective processes and beam-plasma interactions in intense heavy ion beams for applications to ion-beam-driven high energy density physics and heavy ion fusion. The topics include: discussion of the conditions for quiescent beam propagation over long distances; and the electrostatic Harris instability and the transverse electromagnetic Weibel instability in highly anisotropic, intense one-component ion beams. In the longitudinal drift compression and transverse compression regions, collective processes associated with the interaction of the intense ion beam with a charge-neutralizing background plasma are described, including the electrostatic electron-ion two-stream instability, the multispecies electromagnetic Weibel instability, and collective excitations in the presence of a solenoidal magnetic field. The effects of a velocity tilt on reducing two-stream instability growth rates are also discussed. Operating regimes are identified where the possible deleterious effects of collective processes on beam quality are minimized.
Date: June 19, 2008
Creator: Davidson, Ronald C.; Dorf, Mikhail A.; Kaganovich, Igor D.; Qin, Hong; Startsev, Edward A.; Rose, David V. et al.
Object Type: Article
System: The UNT Digital Library
Connecting Galaxies, Halos, and Star Formation Rates Across Cosmic Time (open access)

Connecting Galaxies, Halos, and Star Formation Rates Across Cosmic Time

A simple, observationally-motivated model is presented for understanding how halo masses, galaxy stellar masses, and star formation rates are related, and how these relations evolve with time. The relation between halo mass and galaxy stellar mass is determined by matching the observed spatial abundance of galaxies to the expected spatial abundance of halos at multiple epochs--i.e. more massive galaxies are assigned to more massive halos at each epoch. This 'abundance matching' technique has been shown previously to reproduce the observed luminosity- and scale-dependence of galaxy clustering over a range of epochs. Halos at different epochs are connected by halo mass accretion histories estimated from N-body simulations. The halo-galaxy connection at fixed epochs in conjunction with the connection between halos across time provides a connection between observed galaxies across time. With approximations for the impact of merging and accretion on the growth of galaxies, one can then directly infer the star formation histories of galaxies as a function of stellar and halo mass. This model is tuned to match both the observed evolution of the stellar mass function and the normalization of the observed star formation rate--stellar mass relation to z {approx} 1. The data demands, for example, that the star …
Date: June 2, 2008
Creator: Conroy, Charlie & Wechsler, Risa H.
Object Type: Article
System: The UNT Digital Library
FTR GO14246 (open access)

FTR GO14246

The Maine Forest Bioproducts Research and Development project originally focused on the State’s interest in the development of an integrated forest products refinery (IFPR). The original intent was that Research and Development (R&D) funded by this award will allow Maine to refine its strategy and pursue development of an integrated biorefinery. Activities were to be divided into three major R&D projects: (a) Establish the potential for a forest products biorefinery in Maine, by determining the technical and economic feasibility and resource availability. (b) Investigate and develop conversion processes for forest bioproducts to utilize the sugars available from hemicellulose. Research projects will determine how to best utilize refinery waste streams to recover heat value and recycle remaining components. (c) Cost share very early stage R&D efforts to engage the private sector and stimulate innovative efforts that will build upon the research efforts in (b) above, utilize the information gleaned from (a), and lead to commercialization of new products or services and development of the forest bioproducts industrial sector in Maine.
Date: June 30, 2008
Creator: Bentley, Martha
Object Type: Report
System: The UNT Digital Library
FTR GO14246 (open access)

FTR GO14246

The Maine Forest Bioproducts Research and Development project originally focused on the State’s interest in the development of an integrated forest products refinery (IFPR). The original intent was that Research and Development (R&D) funded by this award will allow Maine to refine its strategy and pursue development of an integrated biorefinery. Activities were to be divided into three major R&D projects: (a) Establish the potential for a forest products biorefinery in Maine, by determining the technical and economic feasibility and resource availability. (b) Investigate and develop conversion processes for forest bioproducts to utilize the sugars available from hemicellulose. Research projects will determine how to best utilize refinery waste streams to recover heat value and recycle remaining components. (c) Cost share very early stage R&D efforts to engage the private sector and stimulate innovative efforts that will build upon the research efforts in (b) above, utilize the information gleaned from (a), and lead to commercialization of new products or services and development of the forest bioproducts industrial sector in Maine.
Date: June 30, 2008
Creator: Bentley, Martha
Object Type: Report
System: The UNT Digital Library
Preliminary Review of Adaptation Options for Climate-Sensitive Ecosystems and Resources (open access)

Preliminary Review of Adaptation Options for Climate-Sensitive Ecosystems and Resources

A report which focuses on federally managed lands and waters to provide a "Preliminary Review of Adaption Options for Climate-Sensitive Ecosystems and Resources."
Date: June 2008
Creator: Climate Change Science Program (U.S.)
Object Type: Report
System: The UNT Digital Library
Awards of Attorneys' Fees by Federal Courts and Federal Agencies (open access)

Awards of Attorneys' Fees by Federal Courts and Federal Agencies

In the United States, the general rule, which derives from common law, is that each side in a legal proceeding pays for its own attorney. There are many exceptions, however, in which federal courts, and occasionally federal agencies, may order the losing party to pay the attorneys' fees of the prevailing party. There are roughly two hundred statutory exceptions, which were generally enacted to encourage private litigation to implement public policy.
Date: June 20, 2008
Creator: Cohen, Henry
Object Type: Report
System: The UNT Digital Library
Evaluation of Aqueous and Powder Processing Techniques for Production of Pu-238-Fueled General Purpose Heat Sources (open access)

Evaluation of Aqueous and Powder Processing Techniques for Production of Pu-238-Fueled General Purpose Heat Sources

This report evaluates alternative processes that could be used to produce Pu-238 fueled General Purpose Heat Sources (GPHS) for radioisotope thermoelectric generators (RTG). Fabricating GPHSs with the current process has remained essentially unchanged since its development in the 1970s. Meanwhile, 30 years of technological advancements have been made in the fields of chemistry, manufacturing, ceramics, and control systems. At the Department of Energy’s request, alternate manufacturing methods were compared to current methods to determine if alternative fabrication processes could reduce the hazards, especially the production of respirable fines, while producing an equivalent GPHS product. An expert committee performed the evaluation with input from four national laboratories experienced in Pu-238 handling.
Date: June 1, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
FCC Record, Volume 23, No. 11, Pages 9024 to 9896, June 9 - June 20, 2008 (open access)

FCC Record, Volume 23, No. 11, Pages 9024 to 9896, June 9 - June 20, 2008

Biweekly, comprehensive compilation of decisions, reports, public notices, and other documents of the U.S. Federal Communications Commission.
Date: June 2008
Creator: United States. Federal Communications Commission.
Object Type: Book
System: The UNT Digital Library