Proposed Specification of EUVL Mask Substrate Roughness (open access)

Proposed Specification of EUVL Mask Substrate Roughness

A revised specification of mask substrate roughness was proposed at the 1st International EUVL Symposium in Dallas in 2002 [1]. This document describes the reasoning behind the proposed revision in more detail. The specification of mask substrate roughness should be based on its effect on lithographic performance. The effects of mask roughness can be considered according to the spatial frequency. At high frequencies (f > M x NA/{lambda}) corresponding to spatial periods too small to be resolved, light is scattered outside the angular acceptance of the camera effectively reducing the reflectivity of the mask. At lower frequencies, f > M x NA/{lambda}, light is scattered within the acceptance angle of the camera and can degrade the aerial image quality. The loss in reflectivity due to high-spatial frequency roughness (HSFR) is given by R/R{sub 0} = exp(-(4{pi}{sigma}/{lambda}){sup 2}), (1) where R{sub 0} is the peak reflectivity of the coating on a smooth substrate, {sigma} is the HSFR after multilayer coating. The relationship between top surface roughness and substrate roughness depends on the multilayer deposition process and significant smoothing of substrate roughness has been demonstrated [2]. Ultimately the specification of HSFR may be best decided based on the multilayer deposition process. For …
Date: September 26, 2003
Creator: Gullikson, E.; Walton, C. C. & Taylor, J. S.
System: The UNT Digital Library
Influence of Environmental Variables on the Susceptibility of Alloy 22 to Environmentally Assisted Cracking (open access)

Influence of Environmental Variables on the Susceptibility of Alloy 22 to Environmentally Assisted Cracking

In its current design, the high-level nuclear waste containers include an external layer of Alloy 22 (NO6022). This material was selected to provide long-term corrosion resistance since if water enters in contact with the containers, they may undergo corrosion. The model for the degradation of the containers includes three modes of corrosion, namely general corrosion, localized corrosion and environmentally assisted cracking (EAC). The objective of the current research was to quantify the susceptibility of Alloy 22 to EAC in several environmental conditions with varying solution composition, temperature and electrochemical potential. The susceptibility to EAC was evaluated using constant deformation (deflection) U-bend specimens in both the wrought and welded conditions. Results show that after more than five years exposure in the vapor and liquid phases of alkaline (PH {approx} 10) and acidic (pH {approx} 3) multi-ionic environments at 60 C and 90 C, Alloy 22 was free from EAC.
Date: September 26, 2002
Creator: Fix, D. V.; Estill, J. C.; King, K. J.; Day, S. D. & Rebak, R. B.
System: The UNT Digital Library
NEW WEB-BASED ACCESS TO NUCLEAR STRUCTURE DATASETS. (open access)

NEW WEB-BASED ACCESS TO NUCLEAR STRUCTURE DATASETS.

As part of an effort to migrate the National Nuclear Data Center (NNDC) databases to a relational platform, a new web interface has been developed for the dissemination of the nuclear structure datasets stored in the Evaluated Nuclear Structure Data File and Experimental Unevaluated Nuclear Data List.
Date: September 26, 2004
Creator: WINCHELL,D. F.
System: The UNT Digital Library
NUCLEAR SCIENCE REFERENCES AS A TOOL FOR DATA EVALUATION. (open access)

NUCLEAR SCIENCE REFERENCES AS A TOOL FOR DATA EVALUATION.

For several decades, the Nuclear Science References database has been maintained as a tool for data evaluators and for the wider pure and applied research community. This contribution will describe the database and recent developments in web-based access.
Date: September 26, 2004
Creator: WINCHELL,D. F.
System: The UNT Digital Library
Staggered grid lagrangian method with local structured adaptive mesh refinement for modeling shock hydrodynamics (open access)

Staggered grid lagrangian method with local structured adaptive mesh refinement for modeling shock hydrodynamics

A new method for the solution of the unsteady Euler equations has been developed. The method combines staggered grid Lagrangian techniques with structured local adaptive mesh refinement (AMR). This method is a precursor to a more general adaptive arbitrary Lagrangian Eulerian (ALE-AMR) algorithm under development, which will facilitate the solution of problems currently at and beyond the boundary of soluble problems by traditional ALE methods by focusing computational resources where they are required. Many of the core issues involved in the development of the ALE-AMR method hinge upon the integration of AMR with a Lagrange step, which is the focus of the work described here. The novel components of the method are mainly driven by the need to reconcile traditional AMR techniques, which are typically employed on stationary meshes with cell-centered quantities, with the staggered grids and grid motion employed by Lagrangian methods. These new algorithmic components are first developed in one dimension and are then generalized to two dimensions. Solutions of several model problems involving shock hydrodynamics are presented and discussed.
Date: September 26, 2000
Creator: Anderson, R W; Pember, R B & Elliot, N S
System: The UNT Digital Library
EVALUATED NUCLEAR STRUCTURE DATA FILE AND RELATED PRODUCTS. (open access)

EVALUATED NUCLEAR STRUCTURE DATA FILE AND RELATED PRODUCTS.

The Evaluated Nuclear Structure Data File (ENSDF) is a leading resource for the experimental nuclear data. It is maintained and distributed by the National Nuclear Data Center, Brookhaven National Laboratory. The file is mainly contributed to by an international network of evaluators under the auspice of the International Atomic Energy Agency. The ENSDF is updated, generally by mass number, i.e., evaluating together all isobars for a given mass number. If, however, experimental activity in an isobaric chain is limited to a particular nuclide then only that nuclide is updated. The evaluations are published in the journal Nuclear Data Sheets, Academic Press, a division of Elsevier.
Date: September 26, 2004
Creator: TULI,J. K.
System: The UNT Digital Library
Phase velocity spectrum analysis for a time delay comb transducer for guided wave mode excitation (open access)

Phase velocity spectrum analysis for a time delay comb transducer for guided wave mode excitation

A theoretical model for the analysis of ultrasonic guided wave mode excitation of a comb transducer with time delay features was developed. Time delay characteristics are included via a Fourier transform into the frequency domain. The phase velocity spectrum can be used to determine the mode excitation on the phase velocity dispersion curves for a given structure. Experimental and theoretical results demonstrate the tuning of guided wave modes using a time delay comb transducer.
Date: September 26, 2000
Creator: Quarry, M J & Rose, J L
System: The UNT Digital Library
NUCLEAR INFORMATION SERVICES AT THE NATIONAL NUCLEAR DATA CENTER. (open access)

NUCLEAR INFORMATION SERVICES AT THE NATIONAL NUCLEAR DATA CENTER.

The National Nuclear Data Center has provided remote access to its databases and other resources since 1986. This year we have completed the modernization of our databases and Web site. Resources available from our Web site will be summarized and some of the major improvements described in more detail.
Date: September 26, 2004
Creator: BURROWS,T. W. & DUNFORD,C. L.
System: The UNT Digital Library
Review of Non-Neutron and Neutron Nuclear Data, 2004. (open access)

Review of Non-Neutron and Neutron Nuclear Data, 2004.

Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non-neutron and neutron nuclear data. Data on the discovery of element 110, Darmstadtium, and element 111 have been officially accepted, while data on element 11 8 have been withdrawn. Data to be presented include revised values for very short-lived nuclides, long-lived nuclides and beta-beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half-lives, which distinguishes between sf decay half-lives and cluster decay half-lives and with cluster-fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor-spectrum, which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement, using neutron activation analysis, will be discussed.
Date: September 26, 2004
Creator: Holden, N. E.
System: The UNT Digital Library
Average Nuclear Level Densities and Radiative Strength Functions in {sup 56,57}FE from Primary (Gamma)-Ray Spectra (open access)

Average Nuclear Level Densities and Radiative Strength Functions in {sup 56,57}FE from Primary (Gamma)-Ray Spectra

An experimental primary {gamma}-ray spectrum vs. excitation-energy bin (P(E{sub x}, E{sub {gamma}}) matrix) in a light-ion reaction is obtained for {sup 56,57}Fe isotopes using a subtraction method. By factorizing the P(E{sub x}, E{sub {gamma}}) matrix according to the Axel-Brink hypothesis the nuclear level density and the radiative strength function (RSF) in {sup 56,57}Fe are extracted simultaneously. A step structure is observed in the level density for both isotopes, and is interpreted as the breaking of Cooper pairs. The RSFs for {sup 56,57}Fe reveal an anomalous enhancement at low {gamma}-ray energies.
Date: September 26, 2002
Creator: Tavukcu, E.; Becker, J. A.; Bernstein, L. A.; Garrett, P. E.; Guttormsen, M.; Mitchell, G. E. et al.
System: The UNT Digital Library
Assessing field-scale migration of mobile radionuclides at the Nevada Test Site (open access)

Assessing field-scale migration of mobile radionuclides at the Nevada Test Site

Numerous long-lived radionuclides, including {sup 99}Tc (technetium) and {sup 129}I (iodine), are present in groundwater at the Nevada Test Site (NTS) as a result of 828 underground nuclear weapons tests conducted between 1951 and 1992. We synthesize a body of groundwater data collected on the distribution of a number of radionuclides ({sup 3}H, {sup 14}C, {sup 36}Cl, {sup 99}Tc and {sup 129}I), which are presumably mobile in the subsurface and potentially toxic to down-gradient receptors, to assess their migration at NTS, at field scales over distances of hundreds of meters and for durations of more than thirty years. Qualitative evaluation of field-scale migration of these radionuclides in the saturated zone provides an independent approach to validating their presumably conservative transport in the performance assessment of the proposed geological repository at Yucca Mountain, which is located on the western edge of NTS. The analyses show that the interaction of {sup 3}H with a solid surface via an isotopic exchange with clay lattice hydroxyls may cause a slight delay in the transport of {sup 3}H. The transport of {sup 14}C could be retarded by its isotopic exchange with carbonate minerals, and the exchange may be more pronounced in the alluvial aquifer. In …
Date: September 26, 2006
Creator: Hu, Q.; Rose, T. P.; Smith, D. K.; Moran, J. E. & Zavarin, M.
System: The UNT Digital Library
Adventures in Coulomb Gauge (open access)

Adventures in Coulomb Gauge

We study the phase structure of SU(2) gauge theories at zero and high temperature, with and without scalar matter fields, in terms of the symmetric/broken realization of the remnant gauge symmetry which exists after fixing to Coulomb gauge. The symmetric realization is associated with a linearly rising color Coulomb potential (which we compute numerically), and is a necessary but not sufficient condition for confinement.
Date: September 26, 2003
Creator: Greensite, J. & Olejnik, S.
System: The UNT Digital Library
Experimental characterization of initial conditions and spatio-temporal evolution of a small Atwood number Rayleigh-Taylor mixing layer (open access)

Experimental characterization of initial conditions and spatio-temporal evolution of a small Atwood number Rayleigh-Taylor mixing layer

The initial multi-mode interfacial velocity and density perturbations present at the onset of a small Atwood number, incompressible, miscible, Rayleigh-Taylor instability-driven mixing layer have been quantified using a combination of experimental techniques. The streamwise interfacial and spanwise interfacial perturbations were measured using high-resolution thermocouples and planar laser-induced fluorescence (PLIF), respectively. The initial multi-mode streamwise velocity perturbations at the two-fluid density interface were measured using particle-image velocimetry (PIV). It was found that the measured initial conditions describe an initially anisotropic state, in which the perturbations in the streamwise and spanwise directions are independent of one another. The evolution of various fluctuating velocity and density statistics, together with velocity and density variance spectra, were measured using PIV and high-resolution thermocouple data. The evolution of the velocity and density statistics is used to investigate the early-time evolution and the onset of strongly-nonlinear, transitional dynamics within the mixing layer. The early-time evolution of the density and vertical velocity variance spectra indicate that velocity fluctuations are the dominant mechanism driving the instability development. The implications of the present experimental measurements on the initialization of Reynolds-averaged turbulent transport and mixing models and of direct and large-eddy simulations of Rayleigh-Taylor instability-induced turbulence are discussed.
Date: September 26, 2005
Creator: Mueschke, N J; Andrews, M J & Schilling, O
System: The UNT Digital Library
High-Efficiency Solar Cells for Large-Scale Electricity Generation (open access)

High-Efficiency Solar Cells for Large-Scale Electricity Generation

One strategy for helping the solar industry to grow faster is to use very high efficiency cells under concentrating optics. By using lenses or mirrors to concentrate the light, very small solar cells can be used, reducing the amount of semiconductor material and allowing use of higher efficiency cells, which are now >40% efficient.
Date: September 26, 2008
Creator: Kurtz, S.; Olson, J.; Geisz, J.; Friedman, D.; McMahon, W.; Ptak, A. et al.
System: The UNT Digital Library
B365 High Efficiency Particulate Air Filter Emergency Replacement An Example of Team Work (open access)

B365 High Efficiency Particulate Air Filter Emergency Replacement An Example of Team Work

None
Date: September 26, 2006
Creator: Coble, T; Little, C & Johnson, R
System: The UNT Digital Library
Thoughts on Verification of Nuclear Disarmament (open access)

Thoughts on Verification of Nuclear Disarmament

It is my pleasure to be here to day to participate in this Conference. My thanks to the organizers for preparing such an interesting agenda on a very difficult topic. My effort in preparing my presentation was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. And as many of you know Lawrence Livermore National Laboratory is now, as of Oct 1st, under contract to the Lawrence Livermore National Security LLC. There has been a long history of how to view verification of arms control agreements. The basis for verification during the days of SALT was that verification would be based on each country's national technical means. For treaties dealing with strategic missiles this worked well as the individual items subject to verification were of such a size that they were visible by the National Technical Means available at the time. And it was felt that the counting of missiles and launchers could be verified by our National Technical Means. For nuclear testing treaties the use of seismic measurements developed into a capability that was reasonably robust for all but the smallest of nuclear tests. However, once we …
Date: September 26, 2007
Creator: Dunlop, W H
System: The UNT Digital Library
Physics Design Requirements for the National Spherical Torus Experiment Liquid Lithium Divertor (open access)

Physics Design Requirements for the National Spherical Torus Experiment Liquid Lithium Divertor

Recent NSTX high power divertor experiments have shown significant and recurring benefits of solid lithium coatings on PFC's to the performance of divertor plasmas in both L- and H- mode confinement regimes heated by high-power neutral beams. The next step in this work is installation of a liquid lithium divertor (LLD) to achieve density control for inductionless current drive capability (e.g., about a 15-25% ne decrease from present highest non-inductionless fraction discharges which often evolve toward the density limit, ne/nGW~1), to enable ne scan capability (x2) in the H-mode, to test the ability to operate at significantly lower density for future ST-CTF reactor designs (e.g., ne/nGW = 0.25), and eventually to investigate high heat-flux power handling (10 MW/m2) with longpulse discharges (>1.5s). The first step (LLD-1) physics design encompasses the desired plasma requirements, the experimental capabilities and conditions, power handling, radial location, pumping capability, operating temperature, lithium filling, MHD forces, and diagnostics for control and characterization.
Date: September 26, 2008
Creator: Kugel, W.; Bell, M.; Berzak,L.; Brooks, A.; Ellis, R.; Gerhardt, S. et al.
System: The UNT Digital Library
Bulk Viscosity, Decaying Dark Matter, and the Cosmic Acceleration (open access)

Bulk Viscosity, Decaying Dark Matter, and the Cosmic Acceleration

The authors discuss a cosmology in which cold dark-matter particles decay into relativistic particles. They argue that such decays could lead naturally to a bulk viscosity in the cosmic fluid. for decay lifetimes comparable to the present hubble age, this bulk viscosity enters the cosmic energy equation as an effective negative pressure. They investigate whether this negative pressure is of sufficient magnitude to account for the observed cosmic acceleration. They show that a single decaying species in a {Lambda} = 0, flat, dark-matter dominated cosmology can not reproduce the observed magnitude-redshift relation from Type Ia supernovae. However, a delayed bulk viscosity, possibly due to a cascade of decaying particles may be able to account for a significant fraction of the apparent cosmic acceleration. Possible candidate nonrelativistic particles for this scenario include sterile neutrinos or gauge-mediated decaying supersymmetric particles.
Date: September 26, 2006
Creator: Wilson, J. R.; Mathews, G. & Fuller, G. M.
System: The UNT Digital Library
EUV micro-exposure tool at 0.5 NA for sub-16 nm lithography (open access)

EUV micro-exposure tool at 0.5 NA for sub-16 nm lithography

The resolution limit of present 0.3 NA 13.5 nm wavelength micro-exposure tools is compared to next generation lithography research requirements. Findings suggest that a successor design is needed for patterning starting at the 16 nm semiconductor process technology node. A two-mirror 0.5 NA optical design is presented, and performance expectations are established from detailed optical and lithographic simulation. Here, we report on the results from a SEMATECH program to fabricate a projection optic with an ultimate resolution limit of approximately 11 nm.
Date: September 26, 2008
Creator: Goldstein, Michael; Hudyma, Russ; Naulleau, Patrick & Wurm, Stefan
System: The UNT Digital Library
Fast Prediction of HCCI and PCCI Combustion with an Artificial Neural Network-Based Chemical Kinetic Model (open access)

Fast Prediction of HCCI and PCCI Combustion with an Artificial Neural Network-Based Chemical Kinetic Model

We have added the capability to look at in-cylinder fuel distributions using a previously developed ignition model within a fluid mechanics code (KIVA3V) that uses an artificial neural network (ANN) to predict ignition (The combined code: KIVA3V-ANN). KIVA3V-ANN was originally developed and validated for analysis of Homogeneous Charge Compression Ignition (HCCI) combustion, but it is also applicable to the more difficult problem of Premixed Charge Compression Ignition (PCCI) combustion. PCCI combustion refers to cases where combustion occurs as a nonmixing controlled, chemical kinetics dominated, autoignition process, where the fuel, air, and residual gas mixtures are not necessarily as homogeneous as in HCCI combustion. This paper analyzes the effects of introducing charge non-uniformity into a KIVA3V-ANN simulation. The results are compared to experimental results, as well as simulation results using a more physically representative and computationally intensive code (KIVA3V-MPI-MZ), which links a fluid mechanics code to a multi-zone detailed chemical kinetics solver. The results indicate that KIVA3V-ANN produces reasonable approximations to the more accurate KIVA3V-MPI-MZ at a much reduced computational cost.
Date: September 26, 2007
Creator: Piggott, W. T.; Aceves, S. M.; Flowers, D. L. & Chen, J. Y.
System: The UNT Digital Library
Induced seismicity associated with enhanced geothermal system (open access)

Induced seismicity associated with enhanced geothermal system

Enhanced Geothermal Systems (EGS) offer the potential to significantly add to the world energy inventory. As with any development of new technology, some aspects of the technology has been accepted by the general public, but some have not yet been accepted and await further clarification before such acceptance is possible. One of the issues associated with EGS is the role of microseismicity during the creation of the underground reservoir and the subsequent extraction of the energy. The primary objectives of this white paper are to present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and to point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced seismicity. The information was collected though literature searches as well as convening three workshops to gather information from a wide audience. Although microseismicity has been associated with the development of production and injection operations in a variety of geothermal regions, there have been no or few adverse physical effects on the …
Date: September 26, 2006
Creator: Majer, Ernest; Majer, Ernest L.; Baria, Roy; Stark, Mitch; Oates, Stephen; Bommer, Julian et al.
System: The UNT Digital Library
Supersymmetry without the Desert (open access)

Supersymmetry without the Desert

Naturalness of electroweak symmetry breaking in weak scale supersymmetric theories may suggest the absence of the conventional supersymmetric desert. We present a simple, realistic framework for supersymmetry in which (most of) the virtues of the supersymmetric desert are naturally reproduced without having a large energy interval above the weak scale. The successful supersymmetric prediction for the low-energy gauge couplings is reproduced due to a gauged R symmetry present in the effective theory at the weak scale. The observable sector superpotential naturally takes the form of the next-to-minimal supersymmetric standard model, but without being subject to the Landau pole constraints up to the conventional unification scale. Supersymmetry breaking masses are generated by the F-term and D-term VEVs of singlet and U(1){sub R} gauge fields, as well as by anomaly mediation, at a scale not far above the weak scale. We study the resulting pattern of supersymmetry breaking masses in detail, and find that it can be quite distinct. We construct classes of explicit models within this framework, based on higher dimensional unified theories with TeV-sized extra dimensions. A similar model based on a non-R symmetry is also presented. These models have a rich phenomenology at the TeV scale, and allow for …
Date: September 26, 2006
Creator: Nomura, Yasunori & Poland, David
System: The UNT Digital Library
21nm X-Ray Laser Thomson Scattering of Laser-Heated Exploding Foil Plasmas (open access)

21nm X-Ray Laser Thomson Scattering of Laser-Heated Exploding Foil Plasmas

Recent experiments were carried out on the Prague Asterix Laser System (PALS) towards the demonstration of a soft x-ray laser Thomson scattering diagnostic for a laser-produced exploding foil. The Thomson probe utilized the Ne-like zinc x-ray laser which was double-passed to deliver {approx}1 mJ of focused energy at 21.2 nm wavelength and lasting {approx}100 ps. The plasma under study was heated single-sided using a Gaussian 300-ps pulse of 438-nm light (3{omega} of the PALS iodine laser) at laser irradiances of 10{sup 13}-10{sup 14} W cm{sup -2}. Electron densities of 10{sup 20}-10{sup 22} cm{sup -3} and electron temperatures from 200 to 500 eV were probed at 0.5 or 1 ns after the peak of the heating pulse during the foil plasma expansion. A flat-field 1200 line mm{sup -1} variable-spaced grating spectrometer with a cooled charge-coupled device readout viewed the plasma in the forward direction at 30{sup o} with respect to the x-ray laser probe. We show results from plasmas generated from {approx}1 {micro}m thick targets of Al and polypropylene (C{sub 3}H{sub 6}). Numerical simulations of the Thomson scattering cross-sections will be presented. These simulations show electron peaks in addition to a narrow ion feature due to collective (incoherent) Thomson scattering. The …
Date: September 26, 2007
Creator: Dunn, J.; Rus, B.; Mocek, T.; Nelson, A. J.; Foord, M. E.; Rozmus, W. et al.
System: The UNT Digital Library
Quasi-isentropic material property studies at extreme pressures: from Omega to NIF (open access)

Quasi-isentropic material property studies at extreme pressures: from Omega to NIF

None
Date: September 26, 2007
Creator: Park, H.; Remington, B. A.; Braun, D.; Celliers, P.; Collins, G. W.; Eggert, J. et al.
System: The UNT Digital Library