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Space-charge compensation in high-intensity proton rings
Recently, it was proposed to use negatively charged electron beams for compensation of beam-beam effects due to protons in the Tevatron collider. The authors show that a similar compensation is possible in space-charge dominated low energy proton beams. The idea has a potential of several-fold increase of the FNAL Booster beam brightness. Best results will be obtained using three electron lenses around the machine circumference, using co-moving electron beam with time structure and profile approximately matched to the proton beam. This technique, if feasible, will be more cost effective than the straightforward alternative of increasing the energy of the injection linac.
Date:
September 21, 2000
Creator:
A. Burov, G.W. Foster and V.D. Shiltsev
Object Type:
Report
System:
The UNT Digital Library
INTRINSIC RESIDUAL STRESSES IN METAL FILMS SYNTHESIZED BY ENERGETIC PARTICLE DEPOSITION
None
Date:
September 15, 2000
Creator:
A. MISRA, M. NASTASI
Object Type:
Article
System:
The UNT Digital Library
Novel Source Ionizer Options for Polarized Ions
N/A
Date:
September 1, 2000
Creator:
A., Hershcovitch
Object Type:
Report
System:
The UNT Digital Library
Polarized proton beam acceleration with a single Siberian Snake in each RHIC ring
N/A
Date:
March 1, 2000
Creator:
A., Lehrach; Luccio, A. U. & Roser, T.
Object Type:
Report
System:
The UNT Digital Library
CATALYSIS SCIENCE AND TECHNOLOGY
This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Our objectives were to develop a multidisciplinary team and capabilities to develop a fundamental understanding of homogeneous, heterogeneous, and heterogenized catalysts. With the aid of theoretical chemistry approaches we explored and characterized the chemical reactivity and physical properties of a large number of catalytic systems.
Date:
August 1, 2000
Creator:
ABRAMS, M.; BAKER, R. & AL, ET
Object Type:
Report
System:
The UNT Digital Library
EFFECTS OF XE ION IRRADIATION AND SUBSEQUENT ANNEALING ON THE PROPERTIES OF MAGNESIUM-ALUMINATE SPINEL
Single crystals of magnesium-aluminate spinel MgAl{sub 2}O{sub 4} were irradiated with 340 keV Xe{sup 2} ions at {minus}173 C ({approximately} 100 K). A fluence of 1 x 10{sup 20} Xe/m{sup 2} created an amorphous layer at the surface of the samples. The samples were annealed for 1 h at different temperatures ranging from 130 C to 880 C. Recrystallization took place in the temperature interval between 610 C and 855 C. Transmission electron microscopy (TEM) images show two distinct layers near the surface: (1) a polycrystalline layer with columnar grain structure; and (2) a buried damaged layer epitaxial with the substrate. After annealing at 1100 C for 52 days, the profile of implanted Xe ions did not change, which means that Xe ions are not mobile in the spinel structure up to 1100 C. The thickness of the buried damaged layer decreased significantly in the 1100 C annealed sample comparing to the sample annealed for 1 h at 855 C.
Date:
April 1, 2000
Creator:
AFANASYEV, I. & AL, ET
Object Type:
Article
System:
The UNT Digital Library
High performance anti-reflection coatings for broadband multi-junction solar cells
The success of bandgap engineering has made high efficiency broadband multi-junction solar cells possible with photo-response out to the band edge of Ge. Modeling has been conducted which suggests that current double layer anti-reflection coating technology is not adequate for these devices in certain cases. Approaches for the development of higher performance anti-reflection coatings are examined. A new AR coating structure based on the use of Herpin equivalent layers is presented. Optical modeling suggests a decrease in the solar weighted reflectance of over 2.5{percent} absolute as a result. This structure requires no additional optical material development and characterization because no new optical materials are necessary. Experimental results and a sensitivity analysis are presented.
Date:
February 23, 2000
Creator:
AIKEN,DANIEL J.
Object Type:
Article
System:
The UNT Digital Library
Spectroscopic Detection of Pathogens
The goal of this LDRD Research project was to provide a preliminary examination of the use of infrared spectroscopy as a tool to detect the changes in cell cultures upon activation by an infectious agent. Due to a late arrival of funding, only 5 months were available to transfer and setup equipment at UTTM,develop cell culture lines, test methods of in-situ activation and collect kinetic data from activated cells. Using attenuated total reflectance (ATR) as a sampling method, live cell cultures were examined prior to and after activation. Spectroscopic data were collected from cells immediately after activation in situ and, in many cases for five successive hours. Additional data were collected from cells activated within a test tube (pre-activated), in both transmission mode as well as in ATR mode. Changes in the infrared data were apparent in the transmission data collected from the pre-activated cells as well in some of the pre-activated ATR data. Changes in the in-situ activated spectral data were only occasionally present due to (1) the limited time cells were studied and (2) incomplete activation. Comparison of preliminary data to infrared bands reported in the literature suggests the primary changes seen are due an increase in ribonucleic …
Date:
November 1, 2000
Creator:
ALAM,M. KATHLEEN; TIMLIN,JERILYN A.; MARTIN,LAURA E.; HJELLE,DRIAN; LYONS,RICK & GARRISON,KRISTIN
Object Type:
Report
System:
The UNT Digital Library
Molecular dynamic simulations, {sup 6}Li solid state NMR and ultraphosphate glasses
The author's laboratory continues to use NMR to investigate the structure and dynamics in amorphous materials, including the local structure of ultraphosphate glasses. Changes in the alkali environment in these phosphate glasses as a function of modifier concentration has recently been probed using {sup 6}Li and {sup 23}Na solid state NMR. Molecular dynamic (MD) simulations have also been performed in an attempt to gain additional insight into the variations of the local structure. Interestingly, although there are distinct variations in the Li coordination number as well as the Li-O bond lengths in the MD simulations (with a minimum or maximum in these parameters near the 20% Li{sub 2}O concentration), a linear change in the {sup 6}Li NMR chemical shift is observed between 5 and 50% Li{sub 2}O mole fraction. One would expect that such variations should be observable in the NMR chemical shift. In an attempt to understand this behavior the author has performed empirical calculation of the {sup 6}Li NMR chemical shift directly from the structures obtained in the MD simulations. It has been argued that the NMR chemical shift of alkali species can be related to a chemical shift parameter A, where A is defined as the summation …
Date:
May 1, 2000
Creator:
ALAM,TODD M.
Object Type:
Article
System:
The UNT Digital Library
Monte Carlo simulations of phosphate polyhedron connectivity in glasses
Monte Carlo simulations of phosphate tetrahedron connectivity distributions in alkali and alkaline earth phosphate glasses are reported. By utilizing a discrete bond model, the distribution of next-nearest neighbor connectivities between phosphate polyhedron for random, alternating and clustering bonding scenarios was evaluated as a function of the relative bond energy difference. The simulated distributions are compared to experimentally observed connectivities reported for solid-state two-dimensional exchange and double-quantum NMR experiments of phosphate glasses. These Monte Carlo simulations demonstrate that the polyhedron connectivity is best described by a random distribution in lithium phosphate and calcium phosphate glasses.
Date:
January 1, 2000
Creator:
ALAM,TODD M.
Object Type:
Report
System:
The UNT Digital Library
Chemometric Analysis of Nuclear Magnetic Resonance Spectroscopy Data
Chemometric analysis of nuclear magnetic resonance (NMR) spectroscopy has increased dramatically in recent years. A variety of different chemometric techniques have been applied to a wide range of problems in food, agricultural, medical, process and industrial systems. This article gives a brief review of chemometric analysis of NMR spectral data, including a summary of the types of mixtures and experiments analyzed with chemometric techniques. Common experimental problems encountered during the chemometric analysis of NMR data are also discussed.
Date:
July 20, 2000
Creator:
ALAM,TODD M. & ALAM,M. KATHLEEN
Object Type:
Article
System:
The UNT Digital Library
MICROHOLE TECHNOLOGY PROGRESS ON BOREHOLE INSTRUMENTATION DEVELOPMENT
Microhole technology development is based on the premise that with advances in electronics and sensors, large conventional-diameter wells are no longer necessary for obtaining subsurface information. Furthermore, microholes offer an environment for improved substance measurement. The combination of deep microholes having diameters of 1-3/8 in. at their terminal depth and 7/8-in. diameter logging tools will comprise a very low cost alternative to currently available technology for deep subsurface characterization and monitoring.
Date:
September 1, 2000
Creator:
ALBRIGHT, J.
Object Type:
Article
System:
The UNT Digital Library
Accident and Off Normal Response and Recovery from Multi Canister Overpack (MCO) Processing Events
In the process of removing spent nuclear fuel (SNF) from the K Basins through its subsequent packaging, drymg, transportation and storage steps, the SNF Project must be able to respond to all anticipated or foreseeable off-normal and accident events that may occur. Response procedures and recovery plans need to be in place, personnel training established and implemented to ensure the project will be capable of appropriate actions. To establish suitable project planning, these events must first be identified and analyzed for their expected impact to the project. This document assesses all off-normal and accident events for their potential cross-facility or Multi-Canister Overpack (MCO) process reversal impact. Table 1 provides the methodology for establishing the event planning level and these events are provided in Table 2 along with the general response and recovery planning. Accidents and off-normal events of the SNF Project have been evaluated and are identified in the appropriate facility Safety Analysis Report (SAR) or in the transportation Safety Analysis Report for Packaging (SARP). Hazards and accidents are summarized from these safety analyses and listed in separate tables for each facility and the transportation system in Appendix A, along with identified off-normal events. The tables identify the general response …
Date:
September 19, 2000
Creator:
ALDERMAN, C.A.
Object Type:
Report
System:
The UNT Digital Library
Fast Grid Search Algorithm for Seismic Source Location
The spatial and temporal origin of a seismic energy source are estimated with a first grid search technique. This approach has greater likelihood of finding the global rninirnum of the arrival time misiit function compared with conventional linearized iterative methods. Assumption of a homogeneous and isotropic seismic velocity model allows for extremely rapid computation of predicted arrival times, but probably limits application of the method to certain geologic environments and/or recording geometries. Contour plots of the arrival time misfit function in the vicinity of the global minimum are extremely useful for (i) quantizing the uncertainty of an estimated hypocenter solution and (ii) analyzing the resolving power of a given recording configuration. In particular, simultaneous inversion of both P-wave and S-wave arrival times appears to yield a superior solution in the sense of being more precisely localized in space and time. Future research with this algorithm may involve (i) investigating the utility of nonuniform residual weighting schemes, (ii) incorporating linear and/or layered velocity models into the calculation of predicted arrival times, and (iii) applying it toward rational design of microseismic monitoring networks.
Date:
July 1, 2000
Creator:
ALDRIDGE,DAVID F.
Object Type:
Report
System:
The UNT Digital Library
SPALL STUDIES IN COPPER FOILS USING THE LASER-DRIVEN MINIFLYER
None
Date:
September 1, 2000
Creator:
ALEXANDER, D. J.; ROBBINS, D. L. & SHEFFIELD, S. A.
Object Type:
Article
System:
The UNT Digital Library
Frequency Doubling Broadband Light in Multiple Crystals
The authors compare frequency doubling of broadband light in a single nonlinear crystal with doubling in five crystals with intercrystal temporal walk off compensation, and with doubling in five crystals adjusted for offset phase matching frequencies. Using a plane-wave, dispersive numerical model of frequency doubling they study the bandwidth of the second harmonic and the conversion efficiency as functions of crystal length and fundamental irradiance. For low irradiance the offset phase matching arrangement has lower efficiency than a single crystal of the same total length but gives a broader second harmonic bandwidth. The walk off compensated arrangement gives both higher conversion efficiency and broader bandwidth than a single crystal. At high irradiance, both multicrystal arrangements improve on the single crystal efficiency while maintaining broad bandwidth.
Date:
July 26, 2000
Creator:
ALFORD,WILLIAM J. & SMITH,ARLEE V.
Object Type:
Article
System:
The UNT Digital Library
Testing Miller Wavelength Scaling of the Second-Order Nonlinear Coefficients of KNbO{sub 3}, KTiOPO{sub 4}, KTiOAsO{sub 4}, LiNbO{sub 3}, LiIO{sub 3}, B-BaB{sub 2}O{sub 4}, KH{sub 2}OP{sub 4}, and LiB{sub 3}O{sub 5}
None
Date:
October 20, 2000
Creator:
ALFORD,WILLIAM J. & SMITH,ARLEE V.
Object Type:
Article
System:
The UNT Digital Library
Wavelength Variation of the Second-Order Nonlinear Coefficients of KNbO3, KTiOPO4, KTiOAsO4, LiNbO3, LiIO3, B-BaB2O4, KH2PO4, and LiB3O5 Crystals: A Test of Miller Wavelength Scaling
None
Date:
July 17, 2000
Creator:
ALFORD,WILLIAM J. & SMITH,ARLEE V.
Object Type:
Article
System:
The UNT Digital Library
INVESTIGATION OF HALO FORMATION IN CONTINUOUS BEAMS USING WEIGHTED POLYNOMIAL EXPANSIONS AND PERTURBATIONAL ANALYSIS
We consider halo formation in continuous beams oscillating at natural modes by inspecting particle trajectories. Trajectory equations containing field nonlinearities are derived from a weighted polynomial expansion. We then use perturbational techniques to further analyze particle motion.
Date:
August 1, 2000
Creator:
ALLEN, C.
Object Type:
Article
System:
The UNT Digital Library
International Workshop on Approaches for Upscaling Processes Affecting Radionuclide Transport through the Subsurface
None
Date:
August 28, 2000
Creator:
ALTMAN,SUSAN J.
Object Type:
Article
System:
The UNT Digital Library
Cooperative Monitoring Center Occasional Paper/16: The Potential of Technology for the Control of Small Weapons: Applications in Developing Countries
For improving the control of small arms, technology provides many possibilities. Present and future technical means are described in several areas. With the help of sensors deployed on the ground or on board aircraft, larger areas can be monitored. Using tags, seals, and locks, important objects and installations can be safeguarded better. With modern data processing and communication systems, more information can be available, and it can be more speedily processed. Together with navigation and transport equipment, action can be taken faster and at greater range. Particular considerations are presented for cargo control at roads, seaports, and airports, for monitoring designated lines, and for the control of legal arms. By starting at a modest level, costs can be kept low, which would aid developing countries. From the menu of technologies available, systems need to be designed for the intended application and with an understanding of the local conditions. It is recommended that states start with short-term steps, such as acquiring more and better radio transceivers, vehicles, small aircraft, and personal computers. For the medium term, states should begin with experiments and field testing of technologies such as tags, sensors, and digital communication equipment.
Date:
July 1, 2000
Creator:
ALTMANN, JURGEN
Object Type:
Report
System:
The UNT Digital Library
Methodology for characterizing modeling and discretization uncertainties in computational simulation
This research effort focuses on methodology for quantifying the effects of model uncertainty and discretization error on computational modeling and simulation. The work is directed towards developing methodologies which treat model form assumptions within an overall framework for uncertainty quantification, for the purpose of developing estimates of total prediction uncertainty. The present effort consists of work in three areas: framework development for sources of uncertainty and error in the modeling and simulation process which impact model structure; model uncertainty assessment and propagation through Bayesian inference methods; and discretization error estimation within the context of non-deterministic analysis.
Date:
March 1, 2000
Creator:
ALVIN,KENNETH F.; OBERKAMPF,WILLIAM L.; RUTHERFORD,BRIAN M. & DIEGERT,KATHLEEN V.
Object Type:
Report
System:
The UNT Digital Library
Use of inelastic analysis in cask design
In this paper, the advantages and disadvantages of inelastic analysis are discussed. Example calculations and designs showing the implications and significance of factors affecting inelastic analysis are given. From the results described in this paper it can be seen that inelastic analysis provides an improved method for the design of casks. It can also be seen that additional code and standards work is needed to give designers guidance in the use of inelastic analysis. Development of these codes and standards is an area where there is a definite need for additional work. The authors hope that this paper will help to define the areas where that need is most acute.
Date:
May 15, 2000
Creator:
AMMERMAN,DOUGLAS J. & BREIVIK,NICOLE L.
Object Type:
Article
System:
The UNT Digital Library
Interim Measures to Limit the Migration of Radioactive Contaminants through the Vadose Zone at Hanford Single Shell Tank (SST) Farms
None
Date:
December 1, 2000
Creator:
ANDERSON, F.J.
Object Type:
Article
System:
The UNT Digital Library