Ion Deflection for Final Optics In Laser Inertial Fusion Power Plants (open access)

Ion Deflection for Final Optics In Laser Inertial Fusion Power Plants

Left unprotected, both transmissive and reflective final optics in a laser inertial fusion power plant would quickly fail from melting, pulsed thermal stresses, or degradation of optical properties as a result of ion implantation. One potential option for mitigating this threat is to magnetically deflect the ions such that they are directed into a robust energy dump. In this paper we detail integrated studies that have been carried out to asses the viability of this approach for protecting final optics.
Date: November 17, 2006
Creator: Abbott, R P & Latkowski, J F
System: The UNT Digital Library
Operation of a Free-Electron Laser from the Extreme Ultraviolet to the Water Window (open access)

Operation of a Free-Electron Laser from the Extreme Ultraviolet to the Water Window

We report results on the performance of a free-electron laser operating at a wavelength of 13.7 nm where unprecedented peak and average powers for a coherent extreme-ultraviolet radiation source have been measured. In the saturation regime, the peak energy approached 170 {micro}J for individual pulses, and the average energy per pulse reached 70 {micro}J. The pulse duration was in the region of 10 fs, and peak powers of 10 GW were achieved. At a pulse repetition frequency of 700 pulses per second, the average extreme-ultraviolet power reached 20mW. The output beam also contained a significant contribution from odd harmonics of approximately 0.6% and 0.03% for the 3rd (4.6 nm) and the 5th (2.75 nm) harmonics, respectively. At 2.75 nm the 5th harmonic of the radiation reaches deep into the water window, a wavelength range that is crucially important for the investigation of biological samples.
Date: December 17, 2007
Creator: Ackermann, W.; Asova, G.; Ayvazyan, V.; Azima, A.; Baboi, N.; Bahr, J. et al.
System: The UNT Digital Library
Wind Resource Development Project for Armenia (open access)

Wind Resource Development Project for Armenia

Armenia has few proven reserves of natural energy and is dependent on long, unreliable transport lines for oil and gas. Preliminary studies indicate that the wind energy potential in Armenia is more than 500 megawatts (MW), assuming a reasonable fraction of 10% of the land area in the high-wind zones. Over the long term, the Armenian government intends to meet 8%--10% of its electric consumption needs by grid-connected wind turbines. The goals of this project are to enhance Armenia's energy security, mitigate the environmental damage of conventional sources of energy, reduce future carbon dioxide emissions, build an environmentally sound and sustainable model for economic development, and promote trade between the U.S. and Armenia. The project is being funded by the Cafesjian Family Foundation, a private foundation based in the United States in Naples, Florida, with the participation of Ecotrade, Inc. of Glendale, California. The National Renewable Energy Laboratory (NREL) is providing technical assistance. As part of the wind energy development project, the authors conducted a preliminary wind-energy resource assessment for some regions in Armenia. This activity provided valuable information needed to facilitate the commercialization of wind farms in Armenia and to lay the groundwork for subsequent wind resource activities. This …
Date: August 17, 2000
Creator: Adamian, S.; Manoukian, L.; Lalayan, A. & Gevorgian, V. (National Renewable Energy Laboratory)
System: The UNT Digital Library
Characterization of Corrosion Products from Static Cell Testing of Al-SNF Forms (open access)

Characterization of Corrosion Products from Static Cell Testing of Al-SNF Forms

Aluminum-based spent nuclear fuel from foreign and domestic research reactors is being consolidated at the Savannah River Site (SRS) for ultimate disposal in the Monitored Geologic Repository. The melt-dilute treatment technology has been developed to consolidate fuel assemblies by a melting/casting process in which depleted uranium is added to reduce enrichment below 20 percent 235-U. The melt-dilute product is essentially a binary uranium-aluminum alloy to which neutron absorber materials may be readily added.
Date: September 17, 2002
Creator: Adams, T.
System: The UNT Digital Library
Off-Gas System Development for the Melt-Dilute Treatment of Aluminum-Based Spent Nuclear Fuel (open access)

Off-Gas System Development for the Melt-Dilute Treatment of Aluminum-Based Spent Nuclear Fuel

This effort will provide a technical basis to assure safe and efficient system operation of the melt-dilute process and have general applicability to off-gas streams.
Date: September 17, 2002
Creator: Adams, T.
System: The UNT Digital Library
Treatment of Legacy Materials Using the Melt-Dilute Treatment Technology (open access)

Treatment of Legacy Materials Using the Melt-Dilute Treatment Technology

This paper reviews the candidate legacy materials and addresses adaptation of the melt-dilute technology to treat DOE legacy waste streams.
Date: September 17, 2002
Creator: Adams, T.
System: The UNT Digital Library
Evaluation of Oxidation and Hydrogen Permeation of Al Containing Duplex Stainless Steels (open access)

Evaluation of Oxidation and Hydrogen Permeation of Al Containing Duplex Stainless Steels

As the National Hydrogen Economy continues to develop and evolve the need for structural materials that can resist hydrogen assisted degradation will become critical. To date austenitic stainless steel materials have been shown to be mildly susceptible to hydrogen attack which results in lower mechanical and fracture strengths. As a result, hydrogen permeation barrier coatings are typically applied to these steel to retard hydrogen ingress. The focal point of the reported work was to evaluate the potential for intentional alloying of commercial 300-series stainless steels to promote hydrogen permeation resistant oxide scales. Previous research on the Cr- and Fe-oxide scales inherent to 300-series stainless steels has proven to be inconsistent in effecting permeation resistance. The approach undertaken in this research was to add aluminum to the 300-series stainless steels in an attempt to promote a pure Al-oxide or and Al-rich oxide scale. Aloxide had been previously demonstrated to be an effective hydrogen permeation barrier. Results for 304L and 347H alloys doped with Al in concentration from 0.5-3.0 wt% with respect to oxidation kinetic studies, cyclic oxidation and characterization of the oxide scale chemistry are reported herein. Gaseous hydrogen permeation testing of the Al-doped alloys in both the unoxidized and oxidized …
Date: June 17, 2005
Creator: Adams, Thad M.; Korinko, Paul & Duncan, Andrew
System: The UNT Digital Library
High-purity, isotopically enriched bulk silicon (open access)

High-purity, isotopically enriched bulk silicon

The synthesis and characterization of dislocation-free, undoped, single crystals of Si enriched in all 3 stable isotopes is reported: {sup 28}Si (99.92%), {sup 29}Si (91.37%), and {sup 30}Si (89.8%). A silane-based process compatible with the relatively small amounts of isotopically enriched precursors that are practically available was used. The silane is decomposed to silicon on a graphite starter rod heated to 700-750 C in a recirculating flow reactor. A typical run produces 35 gm of polycrystalline Si at a growth rates of 5 {micro}m/min and conversion efficiency >95%. Single crystals are grown by the floating zone method and characterized by electrical and optical measurements. Concentrations of shallow dopants (P and B) are as low as mid-10{sup 13} cm{sup -3}. Concentrations of C and O lie below 10{sup 16} and 10{sup 15} cm{sup -3}, respectively.
Date: November 17, 2004
Creator: Ager, J. W., III; Beeman, J. W.; Hansen, W. L.; Haller, E. E.; Sharp, I. D.; Liao, C. et al.
System: The UNT Digital Library
Global Security, Medical Isotopes, and Nuclear Science (open access)

Global Security, Medical Isotopes, and Nuclear Science

Over the past century basic nuclear science research has led to the use of radioactive isotopes into a wide variety of applications that touch our lives everyday. Some are obvious, such as isotopes for medical diagnostics and treatment. Others are less so, such as National/Global security issues. And some we take for granted, like the small amount of 241Am that is in every smoke detector. At the beginning of this century, we are in a position where the prevalence and importance of some applications of nuclear science are pushing the basic nuclear science community for improved models and nuclear data. Yet, at the same time, the push by the basic nuclear science community to study nuclei that are farther and farther away from stability also offer new opportunities for many applications. This talk will look at several global security applications of nuclear science, summarizing current R&D and need for improved nuclear data It will also look at how applications of nuclear science, such as to medicine, will benefit from the push for more and more powerful radioactive ion beam facilities.
Date: September 17, 2007
Creator: Ahle, L. E.
System: The UNT Digital Library
InGaP/GaAs/Ge Multi-Junction Solar Cell Efficiency Improvements Using Epitaxial Germanium (open access)

InGaP/GaAs/Ge Multi-Junction Solar Cell Efficiency Improvements Using Epitaxial Germanium

None
Date: October 17, 2000
Creator: Aiken, Daniel James
System: The UNT Digital Library
The Evolution of Swift/BAT blazars and the origin of the MeV background (open access)

The Evolution of Swift/BAT blazars and the origin of the MeV background

We use 3 years of data from the Swift/BAT survey to select a complete sample of X-ray blazars above 15 keV. This sample comprises 26 Flat-Spectrum Radio Quasars (FSRQs) and 12 BL Lac objects detected over a redshift range of 0.03 < z < 4.0. We use this sample to determine, for the first time in the 15-55 keV band, the evolution of blazars. We find that, contrary to the Seyfert-like AGNs detected by BAT, the population of blazars shows strong positive evolution. This evolution is comparable to the evolution of luminous optical QSOs and luminous X-ray selected AGNs. We also find evidence for an epoch-dependence of the evolution as determined previously for radio-quiet AGNs. We interpret both these findings as a strong link between accretion and jet activity. In our sample, the FSRQs evolve strongly, while our best-fit shows that BL Lacs might not evolve at all. The blazar population accounts for 10-20% (depending on the evolution of the BL Lacs) of the Cosmic X-ray background (CXB) in the 15-55 keV band. We find that FSRQs can explain the entire CXB emission for energies above 500 keV solving the mystery of the generation of the MeV background. The evolution …
Date: October 17, 2009
Creator: Ajello, M.; /SLAC /KIPAC, Menlo Park; Costamante, L.; /Stanford U., HEPL /KIPAC, Menlo Park; Sambruna, R.M.; Gehrels, N. et al.
System: The UNT Digital Library
Surface roughness effects on the solar reflectance of cool asphalt shingles (open access)

Surface roughness effects on the solar reflectance of cool asphalt shingles

We analyze the solar reflectance of asphalt roofing shingles that are covered with pigmented mineral roofing granules. The reflecting surface is rough, with a total area approximately twice the nominal area. We introduce a simple analytical model that relates the 'micro-reflectance' of a small surface region to the 'macro-reflectance' of the shingle. This model uses a mean field approximation to account for multiple scattering effects. The model is then used to compute the reflectance of shingles with a mixture of different colored granules, when the reflectances of the corresponding mono-color shingles are known. Simple linear averaging works well, with small corrections to linear averaging derived for highly reflective materials. Reflective base granules and reflective surface coatings aid achievement of high solar reflectance. Other factors that influence the solar reflectance are the size distribution of the granules, coverage of the asphalt substrate, and orientation of the granules as affected by rollers during fabrication.
Date: February 17, 2008
Creator: Akbari, Hashem; Berdahl, Paul; Akbari, Hashem; Jacobs, Jeffry & Klink, Frank
System: The UNT Digital Library
Overview of Grand Unified Models and their predictions for neutrino oscillations (open access)

Overview of Grand Unified Models and their predictions for neutrino oscillations

A brief overview of Grand Unified Models is presented with some attention paid to their predictions for neutrino oscillations. Given the well-known features of the two non-unified standard models, SM and MSSM, a listing of the features of classes of unified models is given, where a GUT flavor symmetry and/or family symmetry are introduced to reduce the number of model parameters. Some general remarks are then made concerning the type of predictions that follow for the neutrino masses and mixings.
Date: August 17, 2000
Creator: Albright, Carl H.
System: The UNT Digital Library
Les Houches Physics at TeV Colliders 2005 Beyond the Standard Model Working Group: Summary Report (open access)

Les Houches Physics at TeV Colliders 2005 Beyond the Standard Model Working Group: Summary Report

The work contained herein constitutes a report of the ''Beyond the Standard Model'' working group for the Workshop ''Physics at TeV Colliders'', Les Houches, France, 2-20 May, 2005. We present reviews of current topics as well as original research carried out for the workshop. Supersymmetric and non-supersymmetric models are studied, as well as computational tools designed in order to facilitate their phenomenology.
Date: March 17, 2006
Creator: Allanach, B. C.; Grojean, C.; Skands, P.; Accomando, E.; Azuelos, G.; Baer, H. et al.
System: The UNT Digital Library
Performance of a Drum Type Packaging with Urethane Foam Overpack Subjected to Crush and Other Regulatory Tests (open access)

Performance of a Drum Type Packaging with Urethane Foam Overpack Subjected to Crush and Other Regulatory Tests

In order to improve the melt rate of high level waste slurry feed being vitrified in the Savannah River Site's (SRS) Defense Waste Processing Facility (DWPF) Melter, a melter glass pump (pump 1) was installed in the DWPF Melter on February 10, 2004. The glass pump increased melt rate by generating a forced convection within the molten glass pool, thereby increasing the heat transfer from the molten glass to the unmolten feed cold cap that is on top of the glass pool. After operating for over four months, the pump was removed on June 22, 2004 due to indications that it had failed. The removed pump exhibited obvious signs of corrosion, had collapsed inward at the glass exit slots at the melt line, and was dog-legged in the same area. This lead to the pump being redesigned to improve its mechanical integrity (increased wall thickness and strength) while maintaining its hydraulic diameter as large as possible. The improved DWPF glass pump (pump 2) was installed on September 15, 2004. The impact of the new design on pump life, along with analysis of the glass pump's impact on melt rate in the DWPF Melter is discussed in this paper.
Date: July 17, 2005
Creator: Allen, Smith
System: The UNT Digital Library
The effect of low dose rate irradiation on the tensile properties and microstructure of austenitic stainless steel. (open access)

The effect of low dose rate irradiation on the tensile properties and microstructure of austenitic stainless steel.

To assess the effects of long-term, low-dose-rate neutron exposure on mechanical strength and ductility, tensile properties were measured on 12% and 20% cold-worked Type 316 stainless steel. Samples were prepared from reactor core components retrieved from the EBR-II reactor following final shutdown. Sample locations were chosen to cover a dose range of 1-56 dpa at temperatures from 371-440 C and dose rates from 0.5-5.8 x10{sup -7} dpa/s. These dose rates are approximately an order of magnitude lower than those of typical EBR-II test sample locations. The tensile tests for the 12% CW material were performed at 380 C and 430 C while those for the 20% CW samples were performed at 370 C. In each case, the tensile test temperature approximately matched the irradiation temperature. To help understand the tensile properties, microstructural samples with similar irradiation history were also examined. The strength and loss of work hardening increase the fastest as a function of irradiation dose for the 12% CW material irradiated at lower temperature. The decrease in ductility with increasing dose occurs more rapidly for the 12% CW material irradiated at lower temperature and the 20% cold-worked material. Post-tensile test fractography indicates that at higher dose, the 20% CW …
Date: September 17, 2002
Creator: Allen, T. R.; Tsai, H.; Cole, J. I.; Yoshitake, T.; Akasaka, N.; Donomae, T. et al.
System: The UNT Digital Library
LED-induced fluorescence diagnostics for turbine and combustion engine thermometry (open access)

LED-induced fluorescence diagnostics for turbine and combustion engine thermometry

Fluorescence from phosphor coatings is the basis of an established technique for measuring temperature in a wide variety of turbine and combustion engine applications. Example surfaces include blades, vanes, combustors, intake valves, pistons, and rotors. Many situations that are remote and noncontact require the high intensity of a laser to illuminate the phosphor, especially if the surface is moving. Thermometric resolutions of 0.1 C are obtainable, and some laboratory versions of these systems have been calibrated against NIST standards to even higher precision. To improve the measurement signal-to-noise ratio, synchronous detection timing has been used to repeatedly interrogate the same blade in a high speed rotating turbine. High spatial resolution can be obtained by tightly focusing the interrogation beam in measurements of static surfaces, and by precise differential timing of the laser pulses on rotating surfaces. We report here the use of blue light emitting diodes (LEDs) as a n illumination source for producing useable fluorescence from phosphors for temperature measurements. An LED can excite most of the same phosphors used to cover the temperature range from 8 to 1400 C. The advantages of using LEDs are obvious in terms of size, power requirements, space requirements and cost. There can …
Date: August 17, 2001
Creator: Allison, S. W.
System: The UNT Digital Library
Thermal-stress analysis of the high heat-load crotch absorber at the APS. (open access)

Thermal-stress analysis of the high heat-load crotch absorber at the APS.

The Advanced Photon Source (APS) storage ring operation at higher beam current is one of the potential enhancements to increase beam brilliance. However, this would impact the beamline components and high heat-load crotch absorbers. Thus, this analysis is conducted to better understand the impact of higher beam current on water-cooled crotch absorbers, made out of Glidcop, without introducing any heat-related problems.
Date: September 17, 2002
Creator: Alp, A.
System: The UNT Digital Library
Development and Coil Fabrication for the LARP 3.7-m Long Nb3Sn Quadrupole (open access)

Development and Coil Fabrication for the LARP 3.7-m Long Nb3Sn Quadrupole

The U.S. LHC Accelerator Research Program (LARP) has started the fabrication of 3.7-m long Nb{sub 3}Sn quadrupole models. The Long Quadrupoles (LQ) are 'Proof-of-Principle' magnets which are to demonstrate that Nb{sub 3}Sn technology is mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, developed at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. The plans for the LQ R&D and a design update are presented and discussed in this paper. The challenges of fabricating long accelerator-quality Nb{sub 3}Sn coils are presented together with the solutions adopted for the LQ coils (based on the TQ experience). During the fabrication and inspection of practice coils some problems were found and corrected. The fabrication at BNL and FNAL of the set of coils for the first Long Quadrupole is in progress.
Date: August 17, 2008
Creator: Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S. et al.
System: The UNT Digital Library
Fast Neutron Damage Studies on NdFeB Materials (open access)

Fast Neutron Damage Studies on NdFeB Materials

Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and {gamma}'s over the life of the facility [1]. While the linacs will be superconducting, there are still many uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the situation for rare earth, permanent magnet materials was presented at PAC03 [2]. Our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at EPAC04 [3]. We have extended the doses, included other manufacturer's samples, and measured induced radioactivities which are discussed in detail.
Date: May 17, 2005
Creator: Anderson, S.; Spencer, J.; Wolf, Z.; /SLAC; Baldwin, A.; Pellett, D. et al.
System: The UNT Digital Library
Application of a XMM-Newton EPIC Monte Carlo to Analysis And Interpretation of Data for Abell 1689, RXJ0658-55 And the Centaurus Clusters of Galaxies (open access)

Application of a XMM-Newton EPIC Monte Carlo to Analysis And Interpretation of Data for Abell 1689, RXJ0658-55 And the Centaurus Clusters of Galaxies

We propose a new Monte Carlo method to study extended X-ray sources with the European Photon Imaging Camera (EPIC) aboard XMM Newton. The Smoothed Particle Inference (SPI) technique, described in a companion paper, is applied here to the EPIC data for the clusters of galaxies Abell 1689, Centaurus and RXJ 0658-55 (the ''bullet cluster''). We aim to show the advantages of this method of simultaneous spectral-spatial modeling over traditional X-ray spectral analysis. In Abell 1689 we confirm our earlier findings about structure in temperature distribution and produce a high resolution temperature map. We also confirm our findings about velocity structure within the gas. In the bullet cluster, RXJ 0658-55, we produce the highest resolution temperature map ever to be published of this cluster allowing us to trace what looks like the motion of the bullet in the cluster. We even detect a south to north temperature gradient within the bullet itself. In the Centaurus cluster we detect, by dividing up the luminosity of the cluster in bands of gas temperatures, a striking feature to the north-east of the cluster core. We hypothesize that this feature is caused by a subcluster left over from a substantial merger that slightly displaced the …
Date: April 17, 2007
Creator: Andersson, Karl E.; /SLAC, /Stockholm U.; Peterson, J.R.; /Purdue U. /KIPAC, Menlo Park; Madejski, G.M. & /SLAC /KIPAC, Menlo Park
System: The UNT Digital Library
Characterization of Corrosion Damage on Aluminum Fuel Assemblies in Basin Storage (open access)

Characterization of Corrosion Damage on Aluminum Fuel Assemblies in Basin Storage

This paper summarizes the inspections and inspection results in conjunction with the corrosion experience of aluminum-clad SNF in basin storage.
Date: September 17, 2002
Creator: Andes, T.C.
System: The UNT Digital Library
Muons and neutrinos at high-energy accelerators (open access)

Muons and neutrinos at high-energy accelerators

Background levels in detectors and radiation problems at future colliders--whether pp, e{sup +}e{sup {minus}} or {mu}{sup +}{mu}{sup {minus}} are in large part determined by the presence of muons. Neutrinos from muon decay at muon colliders or storage rings are highly collimated and propagate outward within a narrowdisk in which significant radiation doses persist out to very large distances. This paper highlights physics models and Monte Carlo algorithms developed mainly for studying these problems as well as some typical results.
Date: August 17, 2000
Creator: Andreas Van Ginneken, Sergei Striganov and Nikolai Mokhov
System: The UNT Digital Library