Compact, Inexpensive, Safe, and Rapidly Refuelable Hydrogen Storage in Cryogenic Pressure Vessels (open access)

Compact, Inexpensive, Safe, and Rapidly Refuelable Hydrogen Storage in Cryogenic Pressure Vessels

None
Date: September 21, 2012
Creator: Aceves, S. M.; Petitpas, G.; Espinosa-Loza, F.; Matthews, M. J. & Ledesma-Orozco, E.
System: The UNT Digital Library
Observation of Two-Neutrino Double-Beta Decay in Xe-136 with EXO-200 (open access)

Observation of Two-Neutrino Double-Beta Decay in Xe-136 with EXO-200

We report the observation of two-neutrino double-beta decay in {sup 136}Xe with T{sub 1/2} = 2.11 {+-} 0.04(stat) {+-} 0.21(syst) x 10{sup 21} yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for {sup 136}Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.
Date: September 14, 2012
Creator: Ackerman, N.; Aharmim, B.; Auger, M.; Auty, D. J.; Barbeau, P. S.; Barry, K. et al.
System: The UNT Digital Library
Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope (open access)

Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope

Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10{sup -26} cm{sup 3} s{sup -1} at 5 GeV to about 5 x 10{sup -23} cm{sup 3} s{sup -1} at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section ({approx}3 x 10{sup -26} cm{sup 3} s{sup -1} for a purely s-wave cross section), without assuming additional boost factors.
Date: September 14, 2012
Creator: Ackermann, M.; Ajello, M.; Albert, A.; Atwood, W. B.; Baldini, L.; Ballet, J. et al.
System: The UNT Digital Library
In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope (open access)

In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope

The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron-plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between {approx}6 and {approx}13 GeV with an estimated uncertainty of {approx}2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.
Date: September 20, 2012
Creator: Ackermann, M.; Ajello, M.; Allafort, A.; Atwood, W. B.; Axelsson, M.; Baldini, L. et al.
System: The UNT Digital Library
Improving Conservation for First-Order System Least Squares Finite-Element Methods (open access)

Improving Conservation for First-Order System Least Squares Finite-Element Methods

None
Date: September 5, 2012
Creator: Adler, J H & Vassilevski, P S
System: The UNT Digital Library
Gravitomagnetism and Spinor Quantum Mechanics (open access)

Gravitomagnetism and Spinor Quantum Mechanics

We give a systematic treatment of a spin 1=2 particle in a combined electromagnetic field and a weak gravitational field that is produced by a slowly moving matter source. This paper continues previous work on a spin zero particle, but it is largely self-contained and may serve as an introduction to spinors in a Riemann space. The analysis is based on the Dirac equation expressed in generally covariant form and coupled minimally to the electromagnetic field. The restriction to a slowly moving matter source, such as the earth, allows us to describe the gravitational field by a gravitoelectric (Newtonian) potential and a gravitomagnetic (frame-dragging) vector potential, the existence of which has recently been experimentally verified. Our main interest is the coupling of the orbital and spin angular momenta of the particle to the gravitomagnetic field. Specifically we calculate the gravitational gyromagnetic ratio as g{sub g} = 1 ; this is to be compared with the electromagnetic gyromagnetic ratio of g{sub e} = 2 for a Dirac electron.
Date: September 14, 2012
Creator: Adler, Ronald J.; /Stanford U., HEPL /San Francisco State U.; Chen, Pisin; /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park /SLAC; Varani, Elisa & /Unlisted
System: The UNT Digital Library
Fermi Large Area Telescope Observations of the Supernova Remnant G8.7-0.1 (open access)

Fermi Large Area Telescope Observations of the Supernova Remnant G8.7-0.1

We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. An investigation of the relationship between G8.7-0.1 and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.1 and a lesser part located outside the western boundary of G8.7-0.1. The region of the gamma-ray emission overlaps spatially connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 {+-} 0.6 (stat) {+-} 1.2 (sys) GeV, and photon indices of 2.10 {+-} 0.06 (stat) {+-} 0.10 (sys) below the break and 2.70 {+-} 0.12 (stat) {+-} 0.14 (sys) above the break. Given the spatial association among the gamma rays, the radio emission of G8.7-0.1, and the molecular clouds, the decay of p0s produced by particles accelerated in the SNR and hitting the molecular clouds naturally …
Date: September 14, 2012
Creator: Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D. et al.
System: The UNT Digital Library
Higgs, Binos and Gluinos: Split Susy within Reach (open access)

Higgs, Binos and Gluinos: Split Susy within Reach

Recent results from the LHC for the Higgs boson with mass between 142 GeV {approx}< m{sub h{sup 0}} {approx}< 147 GeV points to PeV-scale Split Supersymmetry. This article explores the consequences of a Higgs mass in this range and possible discovery modes for Split Susy. Moderate lifetime gluinos, with decay lengths in the 25 {micro}m to 10 yr range, are its imminent smoking gun signature. The 7TeV LHC will be sensitive to the moderately lived gluinos and trilepton signatures from direct electroweakino production. Moreover, the dark matter abundance may be obtained from annihilation through an s-channel Higgs resonance, with the LSP almost purely bino and mass m{sub {chi}{sub 1}{sup 0}} {approx_equal} 70 GeV. The Higgs resonance region of Split Susy has visible signatures in dark matter direct and indirect detection and electric dipole moment experiments. If the anomalies go away, the majority of Split Susy parameter space will be excluded.
Date: September 14, 2012
Creator: Alves, Daniele S.M.; Izaguirre, Eder; /SLAC /Stanford U., Phys. Dept.; Wacker, Jay G. & /SLAC /Stanford U., ITP
System: The UNT Digital Library
Use of Polycarbonate Vacuum Vessels in High-Temperature Fusion-Plasma Research (open access)

Use of Polycarbonate Vacuum Vessels in High-Temperature Fusion-Plasma Research

Magnetic fusion energy (MFE) research requires ultrahigh-vacuum (UHV) conditions, primarily to reduce plasma contamination by impurities. For radiofrequency (RF)-heated plasmas, a great benefit may accrue from a non-conducting vacuum vessel, allowing external RF antennas which avoids the complications and cost of internal antennas and high-voltage high-current feedthroughs. In this paper we describe these and other criteria, e.g., safety, availability, design flexibility, structural integrity, access, outgassing, transparency, and fabrication techniques that led to the selection and use of 25.4-cm OD, 1.6-cm wall polycarbonate pipe as the main vacuum vessel for an MFE research device whose plasmas are expected to reach keV energies for durations exceeding 0.1 s
Date: September 27, 2012
Creator: B. Berlinger, A. Brooks, H. Feder, J. Gumbas, T. Franckowiak and S.A. Cohen
System: The UNT Digital Library
NUCLEAR ENERGY AND ASTROPHYSICS APPLICATIONS OF ENDF/B-VII.1 EVALUATED NUCLEAR LIBRARY (open access)

NUCLEAR ENERGY AND ASTROPHYSICS APPLICATIONS OF ENDF/B-VII.1 EVALUATED NUCLEAR LIBRARY

N/A
Date: September 3, 2012
Creator: B., Pritychenko
System: The UNT Digital Library
Re-architecting TEIMS Web-based Legacy Applications Using the Model View Controller Paradigm (open access)

Re-architecting TEIMS Web-based Legacy Applications Using the Model View Controller Paradigm

None
Date: September 5, 2012
Creator: Barbosa, E & Laguna, G W
System: The UNT Digital Library
Electron Model Of A Dogbone RLA With Multi-Pass Arcs (open access)

Electron Model Of A Dogbone RLA With Multi-Pass Arcs

The design of a dogbone Recirculated Linear Accelerator, RLA, with linear-field multi-pass arcs was earlier developed [1] for accelerating muons in a Neutrino Factory and a Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over separate-arc or pulsed-arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme, in which a 4.5 MeV electron beam is injected at the middle of a 3 MeV/pass linac with two double-pass return arcs and is accelerated to 18 MeV in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to the frequency readily available at CEBAF: 1.5 GHz. The footprint of a complete RLA fits in an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it straightforward to implement
Date: September 1, 2012
Creator: Beard, Kevin B.; Roblin, Yves R.; Morozov, Vasiliy; Bogacz, Slawomir Alex & Krafft, Geoffrey A.
System: The UNT Digital Library
Developing of superconducting RF guns at BNL (open access)

Developing of superconducting RF guns at BNL

N/A
Date: September 9, 2012
Creator: Belomestnykh, S.; Altinbas, Z.; Ben-Zvi, Ilan; Boulware, C. H.; Brutus, J. C.; Burrill, A. et al.
System: The UNT Digital Library
Superconducting RF linac for eRHIC (open access)

Superconducting RF linac for eRHIC

N/A
Date: September 9, 2012
Creator: Belomestnykh, S.; Ben-Zvi, Ilan; Brutus, J. C.; Hahn, H.; Kayran, D.; Litvinenko, V. et al.
System: The UNT Digital Library
The high-current ERL at BNL (open access)

The high-current ERL at BNL

N/A
Date: September 9, 2012
Creator: Ben-Zvi, Ilan
System: The UNT Digital Library
FIELD-DEPLOYABLE SAMPLING TOOLS FOR SPENT NUCLEAR FUEL INTERROGATION IN LIQUID STORAGE (open access)

FIELD-DEPLOYABLE SAMPLING TOOLS FOR SPENT NUCLEAR FUEL INTERROGATION IN LIQUID STORAGE

Methodology and field deployable tools (test kits) to analyze the chemical and microbiological condition of aqueous spent fuel storage basins and determine the oxide thickness on the spent fuel basin materials were developed to assess the corrosion potential of a basin. this assessment can then be used to determine the amount of time fuel has spent in a storage basin to ascertain if the operation of the reactor and storage basin is consistent with safeguard declarations or expectations and assist in evaluating general storage basin operations. The test kit was developed based on the identification of key physical, chemical and microbiological parameters identified using a review of the scientific and basin operations literature. The parameters were used to design bench scale test cells for additional corrosion analyses, and then tools were purchased to analyze the key parameters. The tools were used to characterize an active spent fuel basin, the Savannah River Site (SRS) L-Area basin. The sampling kit consisted of a total organic carbon analyzer, an YSI multiprobe, and a thickness probe. The tools were field tested to determine their ease of use, reliability, and determine the quality of data that each tool could provide. Characterization confirmed that the L …
Date: September 12, 2012
Creator: Berry, T.; Milliken, C.; Martinez-Rodriguez, M.; Hathcock, D. & Heitkamp, M.
System: The UNT Digital Library
Integrating Wind and Solar Energy in the U.S. Bulk Power System: Lessons from Regional Integration Studies (open access)

Integrating Wind and Solar Energy in the U.S. Bulk Power System: Lessons from Regional Integration Studies

Two recent studies sponsored by the U.S. Department of Energy (DOE) and the National Renewable Energy Laboratory (NREL) have examined the impacts of integrating high penetrations of wind and solar energy on the Eastern and Western electric grids. The Eastern Wind Integration and Transmission Study (EWITS), initiated in 2007, examined the impact on power system operations of reaching 20% to 30% wind energy penetration in the Eastern Interconnection. The Western Wind and Solar Integration Study (WWSIS) examined the operational implications of adding up to 35% wind and solar energy penetration to the Western Interconnect. Both studies examined the costs of integrating variable renewable energy generation into the grid and transmission and operational changes that might be necessary to address higher penetrations of wind or solar generation. This paper identifies key insights from these regional studies for integrating high penetrations of renewables in the U.S. electric grid. The studies share a number of key findings, although in some instances the results vary due to differences in grid operations and markets, the geographic location of the renewables, and the need for transmission.
Date: September 1, 2012
Creator: Bird, L. & Lew, D.
System: The UNT Digital Library
Demixing instability in dense liquid MgSiO3 (open access)

Demixing instability in dense liquid MgSiO3

None
Date: September 28, 2012
Creator: Boates, B & Bonev, S A
System: The UNT Digital Library
Channeling Radiation as a Source of Hard X-Rays With High Spectral Brilliance (open access)

Channeling Radiation as a Source of Hard X-Rays With High Spectral Brilliance

None
Date: September 1, 2012
Creator: Brau, C. A.; Choi, B. -K.; Jarvis, J. D.; Lewellen, J. W. & Piot, P.
System: The UNT Digital Library
Single Phase Melt Processed Powellite (Ba,Ca) MoO{sub 4} For The Immobilization Of Mo-Rich Nuclear Waste (open access)

Single Phase Melt Processed Powellite (Ba,Ca) MoO{sub 4} For The Immobilization Of Mo-Rich Nuclear Waste

Crystalline and glass composite materials are currently being investigated for the immobilization of combined High Level Waste (HLW) streams resulting from potential commercial fuel reprocessing scenarios. Several of these potential waste streams contain elevated levels of transition metal elements such as molybdenum (Mo). Molybdenum has limited solubility in typical silicate glasses used for nuclear waste immobilization. Under certain chemical and controlled cooling conditions, a powellite (Ba,Ca)MoO{sub 4} crystalline structure can be formed by reaction with alkaline earth elements. In this study, single phase BaMoO{sub 4} and CaMoO{sub 4} were formed from carbonate and oxide precursors demonstrating the viability of Mo incorporation into glass, crystalline or glass composite materials by a melt and crystallization process. X-ray diffraction, photoluminescence, and Raman spectroscopy indicated a long range ordered crystalline structure. In-situ electron irradiation studies indicated that both CaMoO{sub 4} and BaMoO{sub 4} powellite phases exhibit radiation stability up to 1000 years at anticipated doses with a crystalline to amorphous transition observed after 1 X 10{sup 13} Gy. Aqueous durability determined from product consistency tests (PCT) showed low normalized release rates for Ba, Ca, and Mo (<0.05 g/m{sup 2}).
Date: September 17, 2012
Creator: Brinkman, Kyle; Marra, James; Fox, Kevin; Reppert, Jason; Crum, Jarrod & Tang, Ming
System: The UNT Digital Library
Beam Loss Control for the Fermilab Main Injector (open access)

Beam Loss Control for the Fermilab Main Injector

None
Date: September 1, 2012
Creator: Brown, Bruce C.
System: The UNT Digital Library
Direct Measurement of Group Delay Dispersion in Metamagnetics for Ultrafast Pulse Shaping (open access)

Direct Measurement of Group Delay Dispersion in Metamagnetics for Ultrafast Pulse Shaping

This article explores the use of magnetic resonant metamaterials, so called metamagnetics, as dispersive elements for optical pulse shaping.
Date: September 24, 2012
Creator: Brown, Dean P.; Walker, Mark A.; Urbas, Augustine M.; Kildishev, Alexander V.; Xiao, Shumin & Drachev, Vladimir P.
System: The UNT Digital Library
Disruptions, Disruptivity, and Safer Operating Windows in the High-β Spherical Torus NSTX (open access)

Disruptions, Disruptivity, and Safer Operating Windows in the High-β Spherical Torus NSTX

A fusion pilot plant study was initiated to clarify the development needs in moving from ITER to a first of a kind fusion power plant. The mission of the pilot plant was set to encompass component test and fusion nuclear science missions yet produce net electricity with high availability in a device designed to be prototypical of the commercial device. The objective of the study was to evaluate three different magnetic configuration options, the advanced tokamak (AT), spherical tokamak (ST) and compact stellarator (CS) in an effort to establish component characteristics, maintenance features and the general arrangement of each candidate device. With the move to look beyond ITER the fusion community is now beginning to embark on DEMO reactor studies with an emphasis on defining configuration arrangements that can meet a high availability goal. This paper reviews the AT pilot plant design, detailing the selected maintenance approach, the device arrangement and sizing of the in-vessel components. Details of interfacing auxiliary systems and services that impact the ability to achieve high availability operations will also be discussed.
Date: September 26, 2012
Creator: Brown, T.; Goldston, R. J.; El-Guebaly, L.; Kessel, C.; Neilson, G. H.; Malang, S. et al.
System: The UNT Digital Library
Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary Formations (open access)

Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary Formations

There is increased recognition that geothermal energy resources are more widespread than previously thought, with potential for providing a significant amount of sustainable clean energy worldwide. Recent advances in drilling, completion, and production technology from the oil and gas industry can now be applied to unlock vast new geothermal resources, with some estimates for potential electricity generation from geothermal energy now on the order of 2 million megawatts. Terralog USA, in collaboration with the University of California, Irvine (UCI), are currently investigating advanced design concepts for paired horizontal well recirculation systems, optimally configured for geothermal energy recovery in permeable sedimentary and crystalline formations of varying structure and material properties. This two-year research project, funded by the US Department of Energy, includes combined efforts for: 1) Resource characterization; 2) Small and large scale laboratory investigations; 3) Numerical simulation at both the laboratory and field scale; and 4) Engineering feasibility studies and economic evaluations. The research project is currently in its early stages. This paper summarizes our technical approach and preliminary findings related to potential resources, small-scale laboratory simulation, and supporting numerical simulation efforts.
Date: September 30, 2012
Creator: Bruno, Mike; Detwiler, Russell L.; Lao, Kang; Serajian, Vahid; Elkhoury, Jean; Diessl, Julia et al.
System: The UNT Digital Library