7Be(p,gamma)8B S-factor from Ab Initio Wave Functions (open access)

7Be(p,gamma)8B S-factor from Ab Initio Wave Functions

There has been a significant progress in ab initio approaches to the structure of light nuclei. Starting from realistic two- and three-nucleon interactions the ab initio no-core shell model (NCSM) predicts low-lying levels in p-shell nuclei. It is a challenging task to extend ab initio methods to describe nuclear reactions. We present here a brief overview of the first steps taken toward nuclear reaction applications. In particular, we discuss our calculation of the {sup 7}Be(p,{gamma}){sup 8}B S-factor. We also present our first results of the {sup 3}He({alpha},{gamma}){sup 7}Be S-factor and of the S-factor of the mirror reaction {sup 3}H({alpha},{gamma}){sup 7}Li. The {sup 7}Be(p,{gamma}){sup 8}B and {sup 3}He({alpha},{gamma}){sup 7}Be reactions correspond to the most important uncertainties in solar model predictions of neutrino fluxes.
Date: October 12, 2006
Creator: Navratil, P; Bertulani, C A & Caurier, E
System: The UNT Digital Library
ACCELERATING POLARIZED PROTONS TO HIGH ENERGY. (open access)

ACCELERATING POLARIZED PROTONS TO HIGH ENERGY.

The Relativistic Heavy Ion Collider (RHIC) is designed to provide collisions of high energy polarized protons for the quest of understanding the proton spin structure. Polarized proton collisions at a beam energy of 100 GeV have been achieved in RHIC since 2001. Recently, polarized proton beam was accelerated to 250 GeV in RHIC for the first time. Unlike accelerating unpolarized protons, the challenge for achieving high energy polarized protons is to fight the various mechanisms in an accelerator that can lead to partial or total polarization loss due to the interaction of the spin vector with the magnetic fields. We report on the progress of the RHIC polarized proton program. We also present the strategies of how to preserve the polarization through the entire acceleration chain, i.e. a 200 MeV linear accelerator, the Booster, the AGS and RHIC.
Date: October 2, 2006
Creator: Bai, M.; Ahrens, L.; Alekseev, I. G.; Alessi, J.; Beebe-Wang, J.; Blaskiewicz, M. et al.
System: The UNT Digital Library
The Accelerator Markup Language and the Universal Accelerator Parser (open access)

The Accelerator Markup Language and the Universal Accelerator Parser

A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally, this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format.
Date: October 6, 2006
Creator: Sagan, D.; Forster, M.; /Cornell U., LNS; Bates, D.A.; /LBL, Berkeley; Wolski, A. et al.
System: The UNT Digital Library
Accelerator Physics Code Web Repository (open access)

Accelerator Physics Code Web Repository

In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this repository, illustrate its usage, and discuss our future plans, with emphasis on code benchmarking.
Date: October 24, 2006
Creator: Zimmermann, F.; Basset, R.; Bellodi, G.; Benedetto, E.; Dorda, U.; Giovannozzi, M. et al.
System: The UNT Digital Library
Advanced Test Reactor Capabilities and Future Irradiation Plans (open access)

Advanced Test Reactor Capabilities and Future Irradiation Plans

The Advanced Test Reactor (ATR), located at the Idaho National Laboratory (INL), is one of the most versatile operating research reactors in the Untied States. The ATR has a long history of supporting reactor fuel and material research for the US government and other test sponsors. The INL is owned by the US Department of Energy (DOE) and currently operated by Battelle Energy Alliance (BEA). The ATR is the third generation of test reactors built at the Test Reactor Area, now named the Reactor Technology Complex (RTC), whose mission is to study the effects of intense neutron and gamma radiation on reactor materials and fuels. The current experiments in the ATR are for a variety of customers--US DOE, foreign governments and private researchers, and commercial companies that need neutrons. The ATR has several unique features that enable the reactor to perform diverse simultaneous tests for multiple test sponsors. The ATR has been operating since 1967, and is expected to continue operating for several more decades. The remainder of this paper discusses the ATR design features, testing options, previous experiment programs, future plans for the ATR capabilities and experiments, and some introduction to the INL and DOE's expectations for nuclear research …
Date: October 1, 2006
Creator: Marshall, Frances M.
System: The UNT Digital Library
Advanced Test Reactor LEU Fuel Conversion Feasibility Study -- 2006 Annual Report (open access)

Advanced Test Reactor LEU Fuel Conversion Feasibility Study -- 2006 Annual Report

The Advanced Test Reactor (ATR) is a high power density and high neutron flux research reactor operating in the U.S. Powered with highly enriched uranium (HEU), the ATR has a maximum thermal power rating of 250 MWth with a maximum unperturbed thermal neutron flux rating of 1.0 x 1015 n/cm2–s. Because of these operating parameters, and the large test volumes located in high flux areas, the ATR is an ideal candidate for assessing the feasibility of converting an HEU driven reactor to a low-enriched core. The present work investigates the necessary modifications and evaluates the subsequent operating effects of this conversion. A detailed plate-by-plate MCNP ATR 1/8th core model was developed and validated for a fuel cycle burnup comparison analysis. Using the current HEU U-235 enrichment of 93.0 % as a baseline, an analysis can be performed to determine the low-enriched uranium (LEU) density and U 235 enrichment required in the fuel meat to yield an equivalent Keff between the HEU core and a LEU core versus effective full power days (EFPD). The MCNP ATR 1/8th core model will be used to optimize the U 235 loading in the LEU core, such that the differences in Keff and heat profile …
Date: October 1, 2006
Creator: Chang, G. S. & Ambrosek, R. G.
System: The UNT Digital Library
AEGIS: The Diversity of Bright Near-IR Selected Distant RedGalaxies (open access)

AEGIS: The Diversity of Bright Near-IR Selected Distant RedGalaxies

We use deep and wide near infrared (NIR) imaging from the Palomar telescope combined with DEEP2 spectroscopy and Hubble Space Telescope (HST) and Chandra Space Telescope imaging to investigate the nature of galaxies that are red in NIR colors. We locate these 'distant red galaxies' (DRGs) through the color cut (J - K){sub vega} > 2.3 over 0.7 deg{sup 2}, where we find 1010 DRG candidates down to K{sub s} = 20.5. We combine 95 high quality spectroscopic redshifts with photometric redshifts from BRIJK photometry to determine the redshift and stellar mass distributions for these systems, and morphological/structural and X-ray properties for 107 DRGs in the Extended Groth Strip. We find that many bright (J - K){sub vega} > 2.3 galaxies with K{sub s} < 20.5 are at redshifts z < 2, with 64% between 1 < z < 2. The stellar mass distributions for these galaxies is broad, ranging from 10{sup 9} - 10{sup 12} M{sub {circle_dot}} , but with most z > 2 systems massive with M{sub *} > 10{sup 11} M{sub {circle_dot}}. HST imaging shows that the structural properties and morphologies of DRGs are also diverse, with the majority elliptical/compact (57%), and the remainder edge-on spirals (7%), …
Date: October 13, 2006
Creator: Conselice, C. J.; Newman, J. A.; Georgakakis, A.; Almaini, O.; Coil, A. L.; Cooper, M. C. et al.
System: The UNT Digital Library
Aerosol sample preparation methods for X-ray diffractive imaging: Size-selected spherical nanoparticles on silicon nitride foils (open access)

Aerosol sample preparation methods for X-ray diffractive imaging: Size-selected spherical nanoparticles on silicon nitride foils

None
Date: October 23, 2006
Creator: Bogan, M. J.; Benner, W. H.; Hau-Riege, S.; Chapman, H. & Frank, M.
System: The UNT Digital Library
[After A Fashion, October 19, 2006] (open access)

[After A Fashion, October 19, 2006]

Article about books seen in the White House, and various events happening around Austin, Texas in October of 2006.
Date: October 19, 2006
Creator: Moser, Stephen MacMillan
System: The UNT Digital Library
The All-Wavelength Extended Groth Strip International Survey(AEGIS) Data Sets (open access)

The All-Wavelength Extended Groth Strip International Survey(AEGIS) Data Sets

In this the first of a series of Letters, we present a description of the panchromatic data sets that have been acquired in the Extended Groth Strip region of the sky. Our survey, the All-wavelength Extended Groth Strip International Survey (AEGIS), is intended to study the physical properties and evolutionary processes of galaxies at z{approx}1. It includes the following deep, wide-field imaging data sets: Chandra/ACIS X-ray (0.5-10 keV), GALEX ultraviolet (1200-2500 Angstroms), CFHT/MegaCam Legacy Survey optical (3600-9000 Angstroms), CFHT/CFH12K optical (4500-9000 Angstroms), Hubble Space Telescope/ACS optical (4400-8500 Angstroms), Palomar/WIRC near-infrared (1.2-2.2 {micro}m), Spitzer/IRAC mid-infrared (3.6-8.0 {micro}m), Spitzer/MIPS far-infrared (24-70 {micro}m), and VLA radio continuum (6-20 cm). In addition, this region of the sky has been targeted for extensive spectroscopy using the DEIMOS spectrograph on the Keck II 10 m telescope. Our survey is compared to other large multiwavelength surveys in terms of depth and sky coverage.
Date: October 13, 2006
Creator: Davis, M.; Guhathakurta, P.; Konidaris, N. P.; Newman, J. A.; Ashby, M. L. N.; Biggs, A. D. et al.
System: The UNT Digital Library
Alloy Films Deposited by Electroplating as Precursors for Protective Oxide Coatings on Solid Oxide Fuel Cells Metallic Interconnect Materials (open access)

Alloy Films Deposited by Electroplating as Precursors for Protective Oxide Coatings on Solid Oxide Fuel Cells Metallic Interconnect Materials

The successful development of stainless steel interconnects for intermediate temperature solid oxide fuel cells (SOFC) may be the materials breakthrough that makes SOFC technology truly commercial. Many of the ferritic stainless steels, however, suffer from a relatively high area specific resistance (ASR) after long exposure times at temperature and the Cr in the native oxide can evaporate and contaminate other cell components. Conductive coatings that resist oxide scale growth and chromium evaporation may prevent both of these problems. In the present study electrochemical deposition of binary alloys followed by oxidation of the alloy to form protective and conductive oxide layers is examined. Results are presented for the deposition of Mn/Co and Fe/Ni alloys via electroplating to form a precursor for spinel oxide coating formation. Analysis of the alloy coatings is done by SEM, EDS and XRD.
Date: October 1, 2006
Creator: Johnson, Christopher; Gemmen, R. S. & Cross, Caleb
System: The UNT Digital Library
Analysis of Br(anti-B ---> X(s gamma)) at NNLO With a Cut on Photon Energy (open access)

Analysis of Br(anti-B ---> X(s gamma)) at NNLO With a Cut on Photon Energy

By combining a recent estimate of the total {bar B} {yields} X{sub s}{gamma} branching fraction at O({alpha}{sub s}{sup 2}) with a detailed analysis of the effects of a cut E{sub {gamma}} {ge} 1.6 GeV on photon energy, a prediction for the partial {bar B} {yields} X{sub s}{gamma} branching fraction at next-to-next-to-leading order in renormalization-group improved perturbation theory is obtained, in which contributions from all relevant scales are properly factorized. The result Br({bar B} {yields} X{sub s}{gamma}) = (2.98 {+-} 0.26) {center_dot} 10{sup -4} is about 1.4{sigma} lower than the experimental world average. This opens a window for significant New Physics contributions in rare radiative B decays.
Date: October 1, 2006
Creator: Becher, Thomas & Neubert, Matthias
System: The UNT Digital Library
Analysis of Carrier Recombination Processes in 0.6 eV InGaAs Epitaxial Materials for Thermophotovoltaic Devices (open access)

Analysis of Carrier Recombination Processes in 0.6 eV InGaAs Epitaxial Materials for Thermophotovoltaic Devices

Minority carrier lifetime was measured by time-resolved photoluminescence (TRPL) method in sets of p-type and n-type InGaAs double heterostructures (DH) moderately doped with Zn and Te, respectively. Contributions of the radiative and non-radiative recombination terms were separated by fitting experimental data to temperature dependences of the radiative term. The latter was modeled with measured fundamental absorption spectrum and the temperature dependence of the photon recycling effect was taken into account. Different temperature dependences of radiative terms for electron and hole materials were obtained. It was concluded that in 0.6 eV Te-doped InGaAs structures the radiative recombination controls the hole lifetime at liquid nitrogen temperatures, while Auger recombination dominates at room and above room temperatures. In similar 0.6 eV InGaAs with Zn-doped active regions Shockley-Read-Hall (SRH) recombination was found dominant in a wide temperature range from liquid nitrogen to above-room temperatures. Rapid decrease of electron lifetime with decrease of excess carrier concentration was observed and attributed to recombination through partially-ionized deep donor centers. The obtained data allows for more adequate modeling of the performance and design optimization of narrow-gap photonic devices based on InGaAs Indium-rich compounds.
Date: October 30, 2006
Creator: Donetsky, D.; Newman, F. & Dashiell, M.
System: The UNT Digital Library
Analytical Scanning and Transmission Electron Microscopy of Laboratory Impacts on Stardust Aluminium Foils: Interpreting Impact Crater Morphology and the Composition of Impact Residues. (open access)

Analytical Scanning and Transmission Electron Microscopy of Laboratory Impacts on Stardust Aluminium Foils: Interpreting Impact Crater Morphology and the Composition of Impact Residues.

The known encounter velocity (6.1kms{sup -1}) between the Stardust spacecraft and the dust emanating from the nucleus of comet Wild 2 has allowed realistic simulation of dust collection in laboratory experiments designed to validate analytical methods for the interpretation of dust impacts on the aluminium foil components of the Stardust collector. In this report we present information on crater gross morphology, the pre-existing major and trace element composition of the foil, geometrical issues for energy dispersive X-ray analysis of the impact residues in scanning electron microscopes, and the modification of dust chemical composition during creation of impact craters as revealed by analytical transmission electron microscopy. Together, these observations help to underpin the interpretation of size, density and composition for particles impacted upon the Stardust aluminium foils.
Date: October 19, 2006
Creator: Kearsley, A T; Graham, G A; Burchell, M J; Cole, M J; Dai, Z R; Teslich, N et al.
System: The UNT Digital Library
[Article: New York Photo Shoot for Brilliant Magazine] (open access)

[Article: New York Photo Shoot for Brilliant Magazine]

Article about a photo shoot held in the streets of New York for the December 2006 issue of Brilliant Magazine.
Date: October 25, 2006
Creator: Bellati, Nally
System: The UNT Digital Library
Assessing the Prospects for Achieving Double-Shell Ignition on the National Ignition Facility Using Vacuum Hohlraums (open access)

Assessing the Prospects for Achieving Double-Shell Ignition on the National Ignition Facility Using Vacuum Hohlraums

The goal of demonstrating ignition on the National Ignition Facility (NIF) has motivated a revisit of double-shell (DS) targets as a complementary path to the cryogenic baseline approach. Expected benefits of DS ignition targets include non-cryogenic deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma mediated laser backscatter, low threshold ignition temperatures ({approx} 4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances, and minimal (two-) shock timing requirements. On the other hand, DS ignition presents several formidable challenges, encompassing room-temperature containment of high-pressure DT ({approx} 790 atm) in the inner shell, strict concentricity requirements on the two shells (< 3 {micro}m), development of nano-porous (<100 nm) low-density (<100 mg/cc) metallic foams for structural support of the inner shell and hydrodynamic instability mitigation, and effective control of hydrodynamic instabilities on the high-Atwood number interface between the DT fuel and the high-Z inner shell. Recent progress in DS ignition designs and required materials-science advances at the nanoscale are described herein. Two new ignition designs that use rugby-shaped vacuum hohlraums are presented which utilize either 1 MJ or 2 MJ of laser energy at 3{omega}. The capability of the NIF to generate the requested reverse-ramp pulse shape for DS ignition is expected to be comparable to …
Date: October 26, 2006
Creator: Amendt, P.; Cerjan, C.; Hamza, A.; Hinkel, D.; Milovich, J. L. & Robey, H. F.
System: The UNT Digital Library
B^0_s mixing at D0 experiment (open access)

B^0_s mixing at D0 experiment

In this report, we present a report on B{sub s}{sup 0} mixing studies at the D0 experiment. New results based on use of two additional decay modes are discussed and limits are given on the B{sub s}{sup 0} mixing parameter.
Date: October 1, 2006
Creator: Moulik, T.; U., /Kansas; Nomerotski, A. & U., /Fermilab /Oxford
System: The UNT Digital Library
Best Practices in Determining the Impacts of Municipal Programs on Energy Use, Air Quality, and Other Ancillary Costs and Benefits (Poster) (open access)

Best Practices in Determining the Impacts of Municipal Programs on Energy Use, Air Quality, and Other Ancillary Costs and Benefits (Poster)

This poster, submitted for the CU Energy Initiative/NREL Symposium on October 3, 2006 held in Boulder, Colorado, discusses best practices for determining the impacts of municipal programs on energy use, air quality, and other costs and benefits.
Date: October 3, 2006
Creator: Brown, E. & Mosey, G.
System: The UNT Digital Library
Black Hole Entropy, Marginal Stability and Mirror Symmetry (open access)

Black Hole Entropy, Marginal Stability and Mirror Symmetry

We consider the superconformal quantum mechanics associated to BPS black holes in type IIB Calabi-Yau compactifications. This quantum mechanics describes the dynamics of D-branes in the near-horizon attractor geometry of the black hole. In many cases, the black hole entropy can be found by counting the number of chiral primaries in this quantum mechanics. Both the attractor mechanism and notions of marginal stability play important roles in generating the large number of microstates required to explain this entropy. We compute the microscopic entropy explicitly in a few different cases, where the theory reduces to quantum mechanics on the moduli space of special Lagrangians. Under certain assumptions, the problem may be solved by implementing mirror symmetry as three T-dualities: this is essentially the mirror of a calculation by Gaiotto, Strominger and Yin. In some simple cases, the calculation may be done in greater generality without resorting to conjectures about mirror symmetry. For example, the K3 x T{sub 2} case may be studied precisely using the Fourier-Mukai transform.
Date: October 6, 2006
Creator: Aspinwall, Paul S.; Maloney, Alexander & Simons, Aaron
System: The UNT Digital Library
Branching Fraction Measurement of B0 to D(*)-pi+and B- to D(*)0pi+ and Isospin Analyses of B to D(*)pi Decays (open access)

Branching Fraction Measurement of B0 to D(*)-pi+and B- to D(*)0pi+ and Isospin Analyses of B to D(*)pi Decays

Using 65 million {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring at the Stanford Linear Accelerator Center, they measure the color-favored branching fractions {Beta}({bar B}{sup 0} {yields} D{sup +}{pi}{sup -}) = (2.63 {+-} 0.05 {+-} 0.22) x 10{sup -3}, {Beta}({bar B}{sup 0} {yields} D*{sup +}{pi}{sup -}) = (2.79 {+-} 0.08 {+-} 0.18) x 10{sup -3}, {Beta}(B{sup -} {yields} D{sup 0}{pi}{sup -}) = (4.90 {+-} 0.07 {+-} 0.23) x 10{sup -3} and {Beta}(B{sup -} {yields} D*{sup 0} {pi}{sup -}) = (5.52 {+-} 0.17 {+-} 0.43) x 10{sup -3}, where the first error is statistical and the second is systematic. With these results and the current world average for the branching fraction for the color-suppressed decay {bar B}{sup 0} {yields} D{sup (*)0}{pi}{sup 0}, the cosines of the strong phase difference {delta} between the I = 1/2 and I = 3/2 isospin amplitudes are determined to be cos{sigma} = 0.860{sub -0.006-0.028}{sup +0.007+0.029} for the {bar B} {yields} D{pi} process and cos{sigma} = 0.917{sub -0.016-0.051}{sup +0.018+0.059} for the {bar B} {yields} D*{pi} process. The results for cos{delta} suggest that final-state interactions are presented in the D{pi} system.
Date: October 17, 2006
Creator: Aubert, B.
System: The UNT Digital Library
Carbon Capture by a Continuous, Regenerative Ammonia-Based Scrubbing Process (open access)

Carbon Capture by a Continuous, Regenerative Ammonia-Based Scrubbing Process

Overview: To develop a knowledge/data base to determine whether an ammonia-based scrubbing process is a viable regenerable-capture technique that can simultaneously remove carbon dioxide, sulfur dioxide, nitric oxides, and trace pollutants from flue gas.
Date: October 1, 2006
Creator: Resnik, K. P.; Yeh, J. T. & Pennline, H. W.
System: The UNT Digital Library
Cathodic Vacuum Arc Plasma of Thallium (open access)

Cathodic Vacuum Arc Plasma of Thallium

Thallium arc plasma was investigated in a vacuum arc ionsource. As expected from previous consideration of cathode materials inthe Periodic Table of the Elements, thallium plasma shows lead-likebehavior. Its mean ion charge state exceeds 2.0 immediately after arctriggering, reaches the predicted 1.60 and 1.45 after about 100 microsecand 150 microsec, respectively. The most likely ion velocity is initially8000 m/s and decays to 6500 m/s and 6200 m/s after 100 microsec and 150microsec, respectively. Both ion charge states and ion velocities decayfurther towards steady state values, which are not reached within the 300microsec pulses used here. It is argued that the exceptionally high vaporpressure and charge exchange reactions are associated with theestablishment of steady state ion values.
Date: October 2, 2006
Creator: Yushkov, Georgy Yu. & Anders, Andre
System: The UNT Digital Library
Cham and Charmoniium Spectroscopy (open access)

Cham and Charmoniium Spectroscopy

The last few years have seen a revival of interest in charm spectroscopy with more than a dozen new states being reported and hundreds of new theoretical investigations being published. The advent of the B-factories [1,2], with their large, charm-rich data samples, has proven crucial to the discovery and investigation of new charm hadron states, but other experiments have confirmed and complemented the B-factory observations. Much interest has been generated by several new states that do not appear to be easily incorporated in the conventional picture of charm and charmonium mesons. Here, the focus is on the latest experimental results in charm spectroscopy and the determination of the nature of the recently discovered states. Recent experimental results in charm and charmonium spectroscopy are reviewed.
Date: October 20, 2006
Creator: Petersen, Brian Aa.
System: The UNT Digital Library
CKM physics at CDF (open access)

CKM physics at CDF

A precise knowledge of the CKM matrix elements is one of the primary goals of the CDF experiment. The Tevatron collider at Fermilab, operating at {radical}s = 1.96, collected 1 fb{sup -1} of data corresponding to a huge b{bar b} sample. In this paper the recent measurements performed in the CKM sector will be presented.
Date: October 1, 2006
Creator: Squillacioti, P. & /Siena U. /INFN, Pisa
System: The UNT Digital Library