ADVANCING THE ION BEAM THIN FILM PLANARIZATION PROCESS FOR THE SMOOTHING OF SUBSTRATE PARTICLES (open access)

ADVANCING THE ION BEAM THIN FILM PLANARIZATION PROCESS FOR THE SMOOTHING OF SUBSTRATE PARTICLES

For a number of technologies small substrate contaminants are undesirable, and for one technology in particular, extreme ultraviolet lithography (EUVL), they can be a very serious issue. We have demonstrated that the Ion Beam Thin Film Planarization Process, a coating process designed to planarize substrate asperities, can be extended to smooth {approx}70 nm and {approx}80 nm diameter particles on EUVL reticle substrates to a height of {approx}0.5 nm, which will render them noncritical in an EUVL printing process. We demonstrate this smoothing process using controlled nanoscale substrate particles and lines fabricated with an e-beam lithography process. The above smoothing process was also modified to yield an excellent reflectance/wavelength uniformity and a good EUV reflectivity for the multilayer, which is required for EUVL reticles. Cross-sectional TEM on a smoothed substrate line defect shows excellent agreement with results obtained from our multilayer growth model.
Date: October 19, 2004
Creator: Mirkarimi, P B; Spiller, E; Baker, S L; Robinson, J C; Stearns, D G; Liddle, J A et al.
System: The UNT Digital Library
Analysis of High-n Dielectronic Rydberg Satellites in the Spectra of Na-like ZnXX and Mg-like ZnXIX (open access)

Analysis of High-n Dielectronic Rydberg Satellites in the Spectra of Na-like ZnXX and Mg-like ZnXIX

We have observed spectra from highly charged zinc ions in a variety of laser-produced plasmas. Spectral features that are Na- and Mg-like satellites to high-n Rydberg transitions in the Ne-like ZnXXI spectrum are analyzed and modeled. Identifications and analysis are made by comparison with highly accurate atomic structure calculations and steady state collisional-radiative models. Each observed ZnXX and ZnXIX feature comprises up to {approx} 2 dozen individual transitions, these transitions are excited principally by dielectronic recombination through autoionizing levels in Na- and Mg-like Zn{sup 19+} Zn{sup 18+}. We find these satellites to be ubiquitous in laser-produced plasmas formed by lasers with pulse lengths that span four orders of magnitude, from 1 ps to {approx} 10 ns. The diagnostic potential of these Rydberg satellite lines is demonstrated.
Date: February 19, 2004
Creator: Petrocelli, G; Vinogradov, V I; Magunov, A I; Flora, F; Martellucci, S; Matafonov, A P et al.
System: The UNT Digital Library
An Approach to Estimate the Localized Effects of an Aircraft Crash on a Facility (open access)

An Approach to Estimate the Localized Effects of an Aircraft Crash on a Facility

Aircraft crashes are an element of external events required to be analyzed and documented in facility Safety Analysis Reports (SARs) and Nuclear Explosive Safety Studies (NESSs). This paper discusses the localized effects of an aircraft crash impact into the Device Assembly Facility (DAF) located at the Nevada Test Site (NTS), given that the aircraft hits the facility. This was done to gain insight into the robustness of the DAF and to account for the special features of the DAF that enhance its ability to absorb the effects of an aircraft crash. For the purpose of this paper, localized effects are considered to be only perforation or scabbing of the facility. This paper presents an extension to the aircraft crash risk methodology of Department of Energy (DOE) Standard 3014. This extension applies to facilities that may find it necessary or desirable to estimate the localized effects of an aircraft crash hit on a facility of nonuniform construction or one that is shielded in certain directions by surrounding terrain or buildings. This extension is not proposed as a replacement to the aircraft crash risk methodology of DOE Standard 3014 but rather as an alternate method to cover situations that were not considered.
Date: April 19, 2004
Creator: Kimura, C; Sanzo, D & Sharirli, M
System: The UNT Digital Library
Atomic Control Of Water Interaction With Biocompatible Surfaces: The Case Of SiC(001) (open access)

Atomic Control Of Water Interaction With Biocompatible Surfaces: The Case Of SiC(001)

The interaction of water with Si- and C- terminated {beta}-SiC(001) surfaces was investigated by means of ab initio molecular dynamics simulations. Irrespective of coverage, varied from 1/4 to 1 monolayer, we found that water dissociates on the Si-terminated surface, substantially modifying the clean surface reconstruction, while the C-terminated surface is nonreactive and hydrophobic. Based on our results, we propose that STM images and photoemission experiments may detect specific changes induced by water on both the structural and electronic properties of SiC(001) surfaces.
Date: July 19, 2004
Creator: Cicero, G; Catellani, A & Galli, G
System: The UNT Digital Library
Biodefense to Cancer Office- Meeting Transcirpt (open access)

Biodefense to Cancer Office- Meeting Transcirpt

None
Date: April 19, 2004
Creator: Felton, J S; Matthews, D L & Lane, S M
System: The UNT Digital Library
Chamber-transport simulation results for heavy-ion fusion drivers (open access)

Chamber-transport simulation results for heavy-ion fusion drivers

The heavy-ion fusion (HIF) community recently developed a power-plant design that meets the various requirements of accelerators, final focus, chamber transport, and targets. The point design is intended to minimize physics risk and is certainly not optimal for the cost of electricity. Recent chamber-transport simulations, however, indicate that changes in the beam ion species, the convergence angle, and the emittance might allow more-economical designs.
Date: October 19, 2004
Creator: Sharp, W. M.; Callahan, D. A.; Tabak, M.; Yu, S. S.; Peterson, P. F.; Rose, D. V. et al.
System: The UNT Digital Library
Clothes washer standards in China -- The problem of water andenergy trade-offs in establishing efficiency standards (open access)

Clothes washer standards in China -- The problem of water andenergy trade-offs in establishing efficiency standards

Currently the sales of clothes washers in China consist ofseveral general varieties. Some use more energy (with or withoutincluding hot water energy use) and some use more water. Both energy andwater are in short supply in China. This poses the question - how do youtrade off water versus energy in establishing efficiency standards? Thispaper discusses how China dealt with this situation and how itestablished minimum efficiency standards for clothes washers.
Date: May 19, 2004
Creator: Biermayer, Peter J. & Lin, Jiang
System: The UNT Digital Library
The Core of NGC 6240 from Keck Adaptive Optics and HST NICMOS Observations (open access)

The Core of NGC 6240 from Keck Adaptive Optics and HST NICMOS Observations

We present results of near infrared imaging of the disk-galaxy-merger NGC 6240 using adaptive optics on the Keck II Telescope and reprocessed archival data from NICMOS on the Hubble Space Telescope. Both the North and South nuclei of NGC 6240 are clearly elongated, with considerable sub-structure within each nucleus. In K' band there are at least two point-sources within the North nucleus; we tentatively identify the south-western point-source within the North nucleus as the position of one of the two AGNs. Within the South nucleus, the northern subnucleus is more highly reddened. Based upon the nuclear separation measured at 5 GHz, we suggest that the AGN in the South nucleus is still enshrouded in dust at K' band, and is located slightly to the north of the brightest point in K' band. Within the South nucleus there is strong H{sub 2} 1-0 S(1) line emission from the northern sub-nucleus, contrary to the conclusions of previous seeing-limited observations. Narrowband H{sub 2} emission-line images show that a streamer or ribbon of excited molecular hydrogen connects the North and South nuclei. We suggest that this linear feature corresponds to a bridge of gas connecting the two nuclei, as seen in computer simulations of …
Date: November 19, 2004
Creator: Max, C. E.; Canalizo, G.; Macintosh, B. A.; Raschke, L.; Whysong, D.; Antonucci, R. et al.
System: The UNT Digital Library
Design Aspects of an MSE Diagnostic for ITER (open access)

Design Aspects of an MSE Diagnostic for ITER

The Motional Stark Effect (MSE) diagnostic is unique in its ability to measure the current profile and will be essential in ITER for detailed analysis of Advanced Tokamak (AT) and other types of discharges. However, design of a MSE diagnostic for ITER presents many unique challenges. Among these is optical analysis for the convoluted optical path, required for effective neutron shielding, that employs several reflective optics arranged to form a labyrinth. The geometry of the diagnostic has been laid out and the expected Doppler shifts and channel resolution calculated. A model of the optical train has also been developed based on the Mueller matrix formalism. Unfolding the pitch angle for this complicated geometry is not straightforward and possible methods are evaluated. The CORSICA code is used to model a variety of ITER discharges including start-up, Ipramp and reverse shear. The code also incorporates a synthetic MSE diagnostic that can be used to evaluate different viewing locations and optimize channel locations for the above discharges. Simulation of the optical emission spectrum is also underway.
Date: April 19, 2004
Creator: Casper, T.; Jayakumar, J.; Makowski, M. & Ellis, R.
System: The UNT Digital Library
Design, fabrication, and characterization of high-efficiency extreme ultraviolet diffusers (open access)

Design, fabrication, and characterization of high-efficiency extreme ultraviolet diffusers

As the development of extreme ultraviolet (EUV) lithography progresses, interest grows in the extension of traditional optical components to the EUV regime. The strong absorption of EUV by most materials and its extremely short wavelength, however, makes it very difficult to implement many components that are commonplace in the longer wavelength regimes. One such example is the diffuser often implemented with ordinary ground glass in the visible light regime. Here we demonstrate the fabrication of reflective EUV diffusers with high efficiency within a controllable bandwidth. Using these techniques we have fabricated diffusers with efficiencies exceeding 10% within a moderate angular single-sided bandwidth of approximately 0.06 radians.
Date: February 19, 2004
Creator: Naulleau, Patrick P.; Liddle, J. Alexander; Salmassi, Farhad; Anderson, Erik H. & Gullikson, Eric M.
System: The UNT Digital Library
A Detailed Modeling Study of Propane Oxidation (open access)

A Detailed Modeling Study of Propane Oxidation

A detailed chemical kinetic mechanism has been used to simulate ignition delay times recorded by a number of experimental shock tube studies over the temperature range 900 {le} T {le} 1800 K, in the pressure range 0.75-40 atm and in the equivalence ratio range 0.5 {le} {phi} {le} 2.0. Flame speed measurements at 1 atm in the equivalence ratio range 0.4 {le} {phi} {le} 1.8 have also been simulated. Both of these data sets, particularly those recorded at high pressure, are of particular importance in validating a kinetic mechanism, as internal combustion engines operate at elevated pressures and temperatures and rates of fuel oxidation are critical to efficient system operation. Experiments in which reactant, intermediate and product species were quantitatively recorded, versus temperature in a jet-stirred reactor (JSR) and versus time in a flow reactor are also simulated. This data provide a stringent test of the kinetic mechanism as it must reproduce accurate quantitative profiles for all reactant, intermediate and product species. The JSR experiments were performed in the temperature range 1000-1110 K, in the equivalence ratio range 0.5 {le} {phi} {le} 4.0, at a pressure of 5 atm. These experiments are complemented by those carried out in a flow …
Date: March 19, 2004
Creator: Westbrook, C. K.; Jayaweera, T. M.; Pitz, W. J. & Curran, H. J.
System: The UNT Digital Library
The Development of Detailed Human Factors Engineering Guidelines for Digital Control Room Upgrades. (open access)

The Development of Detailed Human Factors Engineering Guidelines for Digital Control Room Upgrades.

As part of the Department of Energy and Electric Power Research Institute's hybrid control room project, detailed human factors engineering guidance was developed for designing human-system interfaces that may be affected by introduction of additional digital technology during modernization of nuclear power plants. The guidance addresses several aspects of human-system interaction: information display, interface management, soft controls, alarms, computer-based procedures, computerized operator support systems, communications, and workstation/workplace design. In this paper, the ways in which digital upgrades might affect users' interaction with systems in each of these contexts are briefly described, and the contents of the guidance developed for each of the topics is also described.
Date: September 19, 2004
Creator: Brown, W. & O'Hara, J. M.
System: The UNT Digital Library
Dynamic ionization of water under extreme conditions (open access)

Dynamic ionization of water under extreme conditions

Raman spectroscopy has been used to study fluid water at approximately 1000 K and 2 to 60 GPa in a laser heated diamond anvil cell. First principles molecular dynamics (MD) simulations have also been employed to simulate water under similar conditions. The experimental Raman intensity of the O-H stretch mode was observed to decrease with pressure, and beyond 50 GPa this mode was no longer visible. At approximately the same pressure we inferred a change in the slope of the melting curve. Consistent with these experimental observations, the MD simulations show that water under these conditions forms a dynamically ionized liquid state, which is dominated by very short lived (<10 fs) H{sub 2}O, H{sub 3}O{sup +} and O{sup 2-} species.
Date: July 19, 2004
Creator: Goncharov, A F; Goldman, N; Fried, L E; Crowhurst, J C; Kuo, I W; Mundy, C J et al.
System: The UNT Digital Library
Edge preserving smoothing and segmentation of 4-D images via transversely isotropic scale-space processing and fingerprint analysis (open access)

Edge preserving smoothing and segmentation of 4-D images via transversely isotropic scale-space processing and fingerprint analysis

Enhancements are described for an approach that unifies edge preserving smoothing with segmentation of time sequences of volumetric images, based on differential edge detection at multiple spatial and temporal scales. Potential applications of these 4-D methods include segmentation of respiratory gated positron emission tomography (PET) transmission images to improve accuracy of attenuation correction for imaging heart and lung lesions, and segmentation of dynamic cardiac single photon emission computed tomography (SPECT) images to facilitate unbiased estimation of time-activity curves and kinetic parameters for left ventricular volumes of interest. Improved segmentation of lung surfaces in simulated respiratory gated cardiac PET transmission images is achieved with a 4-D edge detection operator composed of edge preserving 1-D operators applied in various spatial and temporal directions. Smoothing along the axis of a 1-D operator is driven by structure separation seen in the scale-space fingerprint, rather than by image contrast. Spurious noise structures are reduced with use of small-scale isotropic smoothing in directions transverse to the 1-D operator axis. Analytic expressions are obtained for directional derivatives of the smoothed, edge preserved image, and the expressions are used to compose a 4-D operator that detects edges as zero-crossings in the second derivative in the direction of the …
Date: January 19, 2004
Creator: Reutter, Bryan W.; Algazi, V. Ralph; Gullberg, Grant T. & Huesman, Ronald H.
System: The UNT Digital Library
Effects of the Electron Energy Distribution Function on Modeled X-ray Spectra (open access)

Effects of the Electron Energy Distribution Function on Modeled X-ray Spectra

This paper presents the results of a broad investigation into the effects of the electron energy distribution function on the predictions of non-LTE collisional-radiative atomic kinetics models. The effects of non-Maxwellian and suprathermal (''hot'') electron distributions on collisional rates (including three-body recombination) are studied. It is shown that most collisional rates are fairly insensitive to the functional form and characteristic energy of the electron distribution function as long as the characteristic energy is larger than the threshold energy for the collisional process. Collisional excitation and ionization rates, however, are highly sensitive to the fraction of hot electrons. This permits the development of robust spectroscopic diagnostics that can be used to characterize the electron density, bulk electron temperature, and hot electron fraction of plasmas with non-equilibrium electron distribution functions (EDFs). Hot electrons are shown to increase and spread out plasma charge state distributions, amplify the intensities of emission lines fed by direct collisional excitation and radiative cascades, and alter the structure of satellite features in both K- and L-shell spectra. The characteristic energy, functional form, and spatial properties of hot electron distributions in plasmas are open to characterization through their effects on high-energy continuum and line emission and on the polarization …
Date: February 19, 2004
Creator: Shlyaptseva, A S & Hansen, S B
System: The UNT Digital Library
Electron avalanches in liquid argon mixtures (open access)

Electron avalanches in liquid argon mixtures

We have observed stable avalanche gain in liquid argon when mixed with small amounts of xenon in the high electric field (>7 MV/cm) near the point of a chemically etched needle in a point-plane geometry. We identify two gain mechanisms, one pressure dependent, and the other independent of the applied pressure. We conclude that the pressure dependent signals are from avalanche gain in gas bubbles at the tip of the needle, while the pressure independent pulses are from avalanche gain in liquid. We measure the decay time spectra of photons from both types of avalanches. The decay times from the pressure dependent pulses decrease (increase) with the applied pressure (high voltage), while the decay times from the pressure independent pulses are approximately independent of pressure or high voltage. For our operating conditions, the collected charge distribution from avalanches is similar for 60 keV or 122 keV photon sources. With krypton additives, instead of Xe, we measure behavior consistent with only the pressure dependent pulses. Neon and TMS were also investigated as additives, and designs for practical detectors were tested.
Date: March 19, 2004
Creator: Kim, J. G.; Dardin, S. M.; Kadel, R. W.; Kadyk, J. A.; Wenzel, W. B. & Peskov, V.
System: The UNT Digital Library
Electron Clouds and Vacuum Pressure Rise in RHIC. (open access)

Electron Clouds and Vacuum Pressure Rise in RHIC.

The luminosity in RHIC is limited by vacuum pressure rises, observed with high intensity beams of all species (Au{sup 79+}, d{sup +}, p{sup +}). At injection, the pressure rise could be linked to the existence of electron clouds. In addition, pressure rises in the experimental regions may be caused by electron clouds. They review the existing observations, comparisons with simulations, as well as corrective measures taken and planned.
Date: April 19, 2004
Creator: Fischer, W.; Blaskiewicz, M.; He, P.; Huang, H.; Hseuh, H. C.; Iriso, U. et al.
System: The UNT Digital Library
Electroweak Symmetry Breaking via UV Insensitive Anomaly Mediation (open access)

Electroweak Symmetry Breaking via UV Insensitive Anomaly Mediation

Anomaly mediation solves the supersymmetric flavor and CP problems. This is because the superconformal anomaly dictates that supersymmetry breaking is transmitted through nearly flavor-blind infrared physics that is highly predictive and UV insensitive. Slepton mass squareds, however, are predicted to be negative. This can be solved by adding D-terms for U(1)_Y and U(1)_{B-L} while retaining the UV insensitivity. In this paper we consider electroweak symmetry breaking via UV insensitive anomaly mediation in several models. For the MSSM we find a stable vacuum when tanbeta< 1, but in this region the top Yukawa coupling blows up only slightly above the supersymmetry breaking scale. For the NMSSM, we find a stable electroweak breaking vacuum but with a chargino that is too light. Replacing the cubic singlet term in the NMSSM superpotential with a term linear in the singlet wefind a stable vacuum and viable spectrum. Most of the parameter region with correct vacua requires a large superpotential coupling, precisely what is expected in the"Fat Higgs'" model in which the superpotential is generated dynamically. We have therefore found the first viable UV complete, UV insensitive supersymmetry breaking model that solves the flavor and CP problems automatically: the Fat Higgs model with UV insensitive …
Date: February 19, 2004
Creator: Kitano, Ryuichiro; Kribs, Graham D. & Murayama, Hitoshi
System: The UNT Digital Library
Entropic Barriers in Nanoscale Adhesion (open access)

Entropic Barriers in Nanoscale Adhesion

None
Date: March 19, 2004
Creator: Zepeda, S; Noy, A; Orme, C A; DeYoreo, J J & Yeh, Y
System: The UNT Digital Library
EXAMINING CONCEPT OF OPERATIONS IN FUTURE PLANTS. (open access)

EXAMINING CONCEPT OF OPERATIONS IN FUTURE PLANTS.

This paper will examine the results of this research that focus on future concepts of operations. Our approach was to look at current technological developments in the areas of reactor technology, I&C technology, and human-system integration technology and to make projections into the near and longer-term future concerning their potential impact on human performance. The results were discussed in terms of three aspects of concepts of operations: functional staffing models, plant automation, and training and qualifications. Significant changes to each are anticipated and discussed. Research will be needed to address these changes in order to provide for confidence that changes to concepts of operations are accomplished in ways that maintain public safety.
Date: September 19, 2004
Creator: O'HARA,J. M. HIGGINS,J. BROWN,W. KRAMER,J. PERSENSKY,J.
System: The UNT Digital Library
Extremophiles 2004 (open access)

Extremophiles 2004

None
Date: September 19, 2004
Creator: Robb, Frank
System: The UNT Digital Library
Far SOL Transport and Main Wall Plasma Interaction in DIII-D (open access)

Far SOL Transport and Main Wall Plasma Interaction in DIII-D

Far scrape-off layer (SOL) and near-wall plasma parameters in DIII-D depend strongly on the discharge parameters and confinement regime. In L-mode discharges cross-field transport increases with the average discharge density and flattens far SOL profiles, thus increasing plasma-wall contact. In H-mode between edge localized modes (ELMs), plasma-wall contact is generally weaker than in L-mode. During ELMs plasma fluxes to the wall increase to, or above the L-mode levels. Depending on the discharge conditions ELMs are responsible for 30-90% of the ion flux to the outboard chamber wall. Cross-field fluxes in far SOL are dominated by large amplitude intermittent transport events that may propagate all the way to the outer wall and cause sputtering. A Divertor Material Evaluation System (DiMES) probe containing samples of several ITER-relevant materials including carbon, beryllium and tungsten was exposed to a series of upper single null (USN) discharges as a proxy to measure the first wall erosion.
Date: October 19, 2004
Creator: Rudakov, D. L.; Boedo, J. A.; Moyer, R. A.; Stangeby, P. C.; Watkins, J. G.; Whyte, D. G. et al.
System: The UNT Digital Library
Filtration of a Hanford AN-104 Sample (open access)

Filtration of a Hanford AN-104 Sample

The Savannah River Technology Center (SRTC) conducted ultrafiltration tests with samples from the Hanford Site's 241-AN-104 tank. The test objectives were to measure filter flux during dewatering and the removal of soluble species during washing. The filtration tests were conducted with the Cells Unit Filter (CUF) currently installed in Cell 16 of the SRTC High Activity Caves. Following filtration, personnel performed inhibited water washing to remove soluble species. Because of the limited volume of concentrated slurry, the washing was performed with a volumetric flask rather than a crossflow filter. Following the washing, personnel chemically cleaned the filter with 1 M nitric acid and periodically measured the clean water flux.
Date: April 19, 2004
Creator: Poirier, Michael
System: The UNT Digital Library
First-Principle Simulations Of Water (open access)

First-Principle Simulations Of Water

None
Date: March 19, 2004
Creator: Schwegler, E; Grossman, J; Allesch, M & Galli, G
System: The UNT Digital Library