Signals from Microwave Unstable Beams in the SLC Damping Rings (open access)

Signals from Microwave Unstable Beams in the SLC Damping Rings

The longitudinal microwave instability is present in the SLC damping rings during routine operations. Experimental studies of the instability at nominal conditions have been reported previously. To complement those studies and better understand the properties of the instability a series of dedicated experiments were performed under a broad range of operating parameters. These experiments included spectral measurements of BPM signals as well as time domain diagnostics using a custom detecting circuit. This paper describes the techniques, the results and discusses possible interpretations of these measurements.
Date: April 5, 1999
Creator: Podobedev, Boris
Object Type: Report
System: The UNT Digital Library
Diffusion in phase space (open access)

Diffusion in phase space

In order to study diffusion in any region of phase space containing nested closed curves we choose action-angle variables, {gamma}, J. the action J labels each closed phase curve and is equal to its area divided by 2{pi}. We can introduce rectangular variables Q,P by the equations Q=(2J){sup 1/2}sin{gamma}, P=(2J){sup 1/2}cos{gamma}, where the angle variable {gamma} is measured clockwise from the P-axis. The phase curves are circles in the Q,P plane with radius (2J){sup 1/2}. We assume that the motion consists of a Hamiltonian motion along a curve of fixed J (in the original coordinate system and in the system Q,P) plus a diffusion and a damping which can change the value of J. Now consider a system of particles described by a density {rho}(J,t), so that the number of particles between the curves J and J+dJ is dN={rho}(J,t)dJ. These cN particles are distributed uniformly in the phase space between the curves J and J+dJ.
Date: April 5, 1993
Creator: Symon, K.
Object Type: Report
System: The UNT Digital Library
Closed-form approach to checking frame design (open access)

Closed-form approach to checking frame design

This brief report contains calculations of deflections and stresses of the support frame on the XMM project. The goal is to provide an independent view of structural integrity of the frame utilizing a noncomputer approach to design based on elementary closed form solutions and approximate models of mechanical and structural behavior. It is recognized that full confidence can only be assured when computer generated results pertaining to the critical areas and features of the integrating structure can be enveloped by the bracketing solutions. Although the computer solutions have come from the three independent sources, this report utilizes the numerical values from the LLNL studies represented by the computer runs and analysis of the critical elements of the frame. Since the frame geometry, deformation patterns, and the nature of loading are highly complex, this study is restricted to simplified models of selected areas of the structure which can be handled by the conventional formulas and reasonable approximations. This report contains some comments related to material properties, stress concentration, and elements of fracture mechanics directly applicable to frame analysis and design. Such topics and parameters fall usually outside the finite element modeling, but they can have a crucial influence on the mechanical …
Date: April 5, 1995
Creator: Blake, A.
Object Type: Report
System: The UNT Digital Library
Effects of Beamtube Roughness on X-Ray FEL Performance (open access)

Effects of Beamtube Roughness on X-Ray FEL Performance

In an X-Ray FEL like the Linear Coherent Light Source (LCLS) being designed at SLAC, electron bunches about 70 {micro}m FWHM long are sent into a beam tube only 5 mm in internal diameter and more than 100 m in length. Due to the surface roughness of the beam tube, wakefields can be generated that catch up to the bunch and interact with it, causing energy spread and emittance growth. The strength of this effect depends on the details of the roughness of the surface. We present here a study in which the roughness of the beam tube was measured, and the longitudinal impedance of the tube was calculated. Our result shows that commercially available beam tube can be made smooth enough so the resulting wakefield effects are within the tolerance determined by the requirement that the induced relative energy spread of the beam be less then 5 x 10{sup {minus}4}.
Date: April 5, 1999
Creator: Stupakov, Gennady
Object Type: Report
System: The UNT Digital Library
Slag recycling of irradiated vanadium (open access)

Slag recycling of irradiated vanadium

An experimental inductoslag apparatus to recycle irradiated vanadium was fabricated and tested. An experimental electroslag apparatus was also used to test possible slags. The testing was carried out with slag materials that were fabricated along with impurity bearing vanadium samples. Results obtained include computer simulated thermochemical calculations and experimentally determined removal efficiencies of the transmutation impurities. Analyses of the samples before and after testing were carried out to determine if the slag did indeed remove the transmutation impurities from the irradiated vanadium.
Date: April 5, 1995
Creator: Gorman, P.K.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Effects of Damage on Hydrogen-Implant-Induced Thin-Film Separation from Bulk Silicon Carbide (open access)

The Effects of Damage on Hydrogen-Implant-Induced Thin-Film Separation from Bulk Silicon Carbide

Exfoliation of Sic by hydrogen implantation and subsequent annealing forms the basis for a thin-film separation process which, when combined with hydrophilic wafer bonding, can be exploited to produce silicon-carbide-on-insulator, SiCOI. Sic thin films produced by this process exhibit unacceptably high resistivity because defects generated by the implant neutralize electrical carriers. Separation occurs because of chemical interaction of hydrogen with dangling bonds within microvoids created by the implant, and physical stresses due to gas-pressure effects during post-implant anneal. Experimental results show that exfoliation of Sic is dependent upon the concentration of implanted hydrogen, but the damage generated by the implant approaches a point when exfoliation is, in fact, retarded. This is attributed to excessive damage at the projected range of the implant which inhibits physical processes of implant-induced cleaving. Damage is controlled independently of hydrogen dosage by elevating the temperature of the SiC during implant in order to promote dynamic annealing. The resulting decrease in damage is thought to promote growth of micro-cracks which form a continuous cleave. Channeled H{sup +} implantation enhances the cleaving process while simultaneously minimizing residual damage within the separated film. It is shown that high-temperature irradiation and channeling each reduces the hydrogen fluence required to …
Date: April 5, 1999
Creator: Gregory, R. B.; Holland, O. W.; Thomas, D. K.; Wetteroth, T. A. & Wilson, S. R.
Object Type: Article
System: The UNT Digital Library
Demonstration, testing, and evaluation of in situ heating of soil. Final report, Volume 2, Appendices A to E (open access)

Demonstration, testing, and evaluation of in situ heating of soil. Final report, Volume 2, Appendices A to E

This is a final report presented in two volumes. Volume I contains the technical report and Volume II contains appendices with background information and data. In this project approximately 300 cubic yards of clayey soil containing a low concentration plume of volatile organic chemicals was heated in situ by the application of electrical energy. It was shown that as a result of heating the effective permeability of soil to air flow was increased such that in situ soil vapor extraction could be performed. The initial permeability of soil was so low that the soil gas flow rate was immeasurably small even at high vacuum levels. It was demonstrated that the mass flow rate of the volatile organic chemicals was enhanced in the recovered soil gas as a result of heating. When scaled up, this process can be used for the environmental clean up and restoration of DOE sites contaminated with VOC`s and other organic chemicals. Although it may be applied to many types of soil formations, it is particularly attractive for low permeability clayey soil where conventional in situ venting techniques are limited by air flow.
Date: April 5, 1996
Creator: Dev, H.; Enk, J.; Jones, D. & Sabato, W.
Object Type: Report
System: The UNT Digital Library
EPICS: Allen-Bradley hardware reference manual (open access)

EPICS: Allen-Bradley hardware reference manual

This manual covers the following hardware: Allen-Bradley 6008 -- SV VMEbus I/O scanner; Allen-Bradley universal I/O chassis 1771-A1B, -A2B, -A3B, and -A4B; Allen-Bradley power supply module 1771-P4S; Allen-Bradley 1771-ASB remote I/O adapter module; Allen-Bradley 1771-IFE analog input module; Allen-Bradley 1771-OFE analog output module; Allen-Bradley 1771-IG(D) TTL input module; Allen-Bradley 1771-OG(d) TTL output; Allen-Bradley 1771-IQ DC selectable input module; Allen-Bradley 1771-OW contact output module; Allen-Bradley 1771-IBD DC (10--30V) input module; Allen-Bradley 1771-OBD DC (10--60V) output module; Allen-Bradley 1771-IXE thermocouple/millivolt input module; and the Allen-Bradley 2705 RediPANEL push button module.
Date: April 5, 1993
Creator: Nawrocki, G.
Object Type: Report
System: The UNT Digital Library
Demonstration, testing, and evaluation of in situ heating of soil. Volume 1, Final report (open access)

Demonstration, testing, and evaluation of in situ heating of soil. Volume 1, Final report

This document is a final reports in two volumes. Volume I contains the technical report and Volume II contains appendices with background information and data. In this project approximately 300 cubic yards of clayey soil containing a low concentration plume of volatile organic chemicals was heated in situ by the application of electrical energy. It was shown that as a result of heating the effective permeability of soil to air flow was increased such that in situ soil vapor extraction could be performed. The initial permeability of soil was so low that the soil gas flow rate was immeasurably small even at high vacuum levels. It was demonstrated that the mass flow rate of the volatile organic chemicals was enhanced in the recovered soil gas as a result of heating.
Date: April 5, 1996
Creator: Dev, H.; Enk, J.; Jones, D. & Sabato, W.
Object Type: Report
System: The UNT Digital Library
Development of a system of innovative insulated building blocks under energy related inventions grant. Quarterly progress report, ThermaLock Products, Inc., October 1, 1992--April 30, 1993 (open access)

Development of a system of innovative insulated building blocks under energy related inventions grant. Quarterly progress report, ThermaLock Products, Inc., October 1, 1992--April 30, 1993

Progress is reported on research pertaining to insulated building blocks. Areas covered include coursing, the development of a stuffing machine, block fabrication, designs for earthquake testing, and sound tests.
Date: April 5, 1993
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Real time programming environment for Windows, Appendix A (open access)

Real time programming environment for Windows, Appendix A

This appendix contains all source code for the RTProE system. The following file contents are included: pdb.h; hgen.l; hgen.y; igen.l; igen.y; pdm.l; pdm.y; rtdata.l; rtdata.y; framegen.c; librt.c; librt.h; rtsched.c; build.tsh; sde.tcl; rtsched.def.
Date: April 5, 1998
Creator: unknown
Object Type: Article
System: The UNT Digital Library
Modified Aladdin lattice L2V2 (open access)

Modified Aladdin lattice L2V2

The N30 lattice discussed in a previous note showed that a nearly matched lattice could be produced by separating four of the present quadrupole from their present power supplies and powering them separately. Although having significantly higher dynamic aperture, less closed orbit distortion and improved natural emittance compared to the present Aladdin lattice, the proximity of the {nu}{sub x} = 5.24 tune was felt to be too close to the 3{nu}{sub x} = 16 (a structure resonance) and the tune should be raised. In order to demonstrate the tunability of this modified lattice, Yang Cho found a new tune ({nu}{sub x} = 6.27, {nu}{sub y} = 6.23), hereafter called L2V2 lattice. This lattice, although not as nicely matched as the N30 lattice, has a 10% lower natural emittance and considerably more dynamic aperture. The L2V2 lattice has not been fully optimized, but is sufficient to demonstrate the advantages of this modified Aladdin lattice.
Date: April 5, 1985
Creator: Kramer, S. & Cho, Y.
Object Type: Report
System: The UNT Digital Library
An Anticipatory Model of Cavitation (open access)

An Anticipatory Model of Cavitation

The Anticipatory System (AS) formalism developed by Robert Rosen provides some insight into the problem of embedding intelligent behavior in machines. AS emulates the anticipatory behavior of biological systems. AS bases its behavior on its expectations about the near future and those expectations are modified as the system gains experience. The expectation is based on an internal model that is drawn from an appeal to physical reality. To be adaptive, the model must be able to update itself. To be practical, the model must run faster than real-time. The need for a physical model and the requirement that the model execute at extreme speeds, has held back the application of AS to practical problems. Two recent advances make it possible to consider the use of AS for practical intelligent sensors. First, advances in transducer technology make it possible to obtain previously unavailable data from which a model can be derived. For example, acoustic emissions (AE) can be fed into a Bayesian system identifier that enables the separation of a weak characterizing signal, such as the signature of pump cavitation precursors, from a strong masking signal, such as a pump vibration feature. The second advance is the development of extremely fast, …
Date: April 5, 1999
Creator: Allgood, G. O.; Dress Jr., W. B.; Hylton, J. O. & Kercel, S. W.
Object Type: Article
System: The UNT Digital Library
Infrared Imaging of Temperature Distribution in a High Temperature X-Ray Diffraction Furnace (open access)

Infrared Imaging of Temperature Distribution in a High Temperature X-Ray Diffraction Furnace

High Temperature X-ray Diffraction (HTXRD) is a very powerful tool for studies of reaction kinetics, phase transformations, and lattice thermal expansion of advanced materials. Accurate temperature measurement is a critical part of the technique. Traditionally, thermocouples, thermistors, and optical pyrometers have been used for temperature control and measurement and temperature could only be measured at a single point. Infrared imaging was utilized in this study to characterize the thermal gradients resulting from various sample and furnace configurations in a commercial strip heater furnace. Furnace configurations include a metallic strip heater, with and without a secondary surround heater, or a surround heater alone. Sample configurations include low and high thermal conductivity powders and solids. The IR imaging results have been used to calibrate sample temperatures in the HTXRD furnace.
Date: April 5, 1999
Creator: Payzant, E. A. & Wang, H.
Object Type: Article
System: The UNT Digital Library
Transformation as a Design Process and Runtime Architecture for High Integrity Software (open access)

Transformation as a Design Process and Runtime Architecture for High Integrity Software

We have discussed two aspects of creating high integrity software that greatly benefit from the availability of transformation technology, which in this case is manifest by the requirement for a sophisticated backtracking parser. First, because of the potential for correctly manipulating programs via small changes, an automated non-procedural transformation system can be a valuable tool for constructing high assurance software. Second, modeling the processing of translating data into information as a, perhaps, context-dependent grammar leads to an efficient, compact implementation. From a practical perspective, the transformation process should begin in the domain language in which a problem is initially expressed. Thus in order for a transformation system to be practical it must be flexible with respect to domain-specific languages. We have argued that transformation applied to specification results in a highly reliable system. We also attempted to briefly demonstrate that transformation technology applied to the runtime environment will result in a safe and secure system. We thus believe that the sophisticated multi-lookahead backtracking parsing technology is central to the task of being in a position to demonstrate the existence of HIS.
Date: April 5, 1999
Creator: Bespalko, Stephen J. & Winter, Victor L.
Object Type: Article
System: The UNT Digital Library
Reliability Testing of Polysilicon For MEMs Devices (open access)

Reliability Testing of Polysilicon For MEMs Devices

Mission critical applications of MEMS devices require knowledge of the distribution in their material properties and long-term reliability of the small-scale structures. This project reports on a new testing program at Sandia to quantify the strength distribution using samples that reflect the dimensions of critical MEMS components. The strength of polysilicon fabricated with Sandia's SUMMiT 4-layer process was successfully measured using samples with gage sections 2.5 {micro}m thick by 1.7 {micro}m wide and lengths of 15 and 25 {micro}m. These tensile specimens have a freely moving pivot on one end that anchors the sample to the silicon die and prevents off axis loading during testing. Each sample is loaded in uniaxial tension by pulling laterally with a flat tipped diamond in a computer-controlled Nanoindenter. The stress-strain curve is calculated using the specimen cross section and gage length dimensions verified by measuring against a standard in the SEM. The first 48 samples had a means strength of 2.24 {+-} 0.35 GPa. Fracture strength measurements grouped into three strength levels, which matched three failure modes observed in post mortem examinations. The seven samples in the highest strength group failed in the gage section (strength of 2.77 {+-} 0.04 GPa), the moderate strength …
Date: April 5, 1999
Creator: LaVan, D.A. & Buchheit, T.E.
Object Type: Article
System: The UNT Digital Library
Feature, Event, and Process Screening and Scenario Development for the Yucca Mountain Total System Performance Assessment (open access)

Feature, Event, and Process Screening and Scenario Development for the Yucca Mountain Total System Performance Assessment

Scenario development has two primary purposes in the design and documentation of post-closure performance assessments in a regulatory setting. First, scenario development ensures a sufficiently comprehensive consideration of the possible future states of the system. Second, scenario development identifies the important scenarios that must be considered in quantitative analyses of the total system performance assessment (TSPA). Section 2.0 of this report describes the scenario development process. Steps in the process are described in Section 2.1, and terms introduced in this section are defined in Section 2.2. The electronic database used to document the process is described in Section 3, and Section 4 provides a summary of the current status of the YMP scenario development work. Section 5 contains acknowledgments, and Section 6 contains a list of the references cited.
Date: April 5, 1999
Creator: Barnard, R.; Barr, G.; Burch, P.; Freeze, G.; Rechard, R.; Schenker, A. et al.
Object Type: Article
System: The UNT Digital Library
Growth and Structure of Metallic Barrier Layer and Interconnect Films I: Experiments (open access)

Growth and Structure of Metallic Barrier Layer and Interconnect Films I: Experiments

We present experimented results directed at understanding the growth and structure of metallic barrier layer and interconnect films. Numerical simulation results associated with this experimental work are presented in an accompanying paper in these proceedings. Here, thin films of Al, Ti, Cu and Ta have been grown by magnetron sputtering onto oxidized Si substrates. Using a specially-constructed substrate holder, the orientation of the substrate with respect to the growth direction was varied from horizontal to vertical. Films were grown at both low and high argon pressure; in the case of Ta, the cathode power was varied as well. The film structure and in particular the surface roughness was measured by X-ray reflectance and also by atomic force microscopy. We find that the surface roughness increases markedly with orientation angle in the case of Ta and Cu films, and in Ti films grown at high argon pressure. At low pressure, however, the Ti film surface roughness remains constant for all substrate orientations. No variation in roughness with either orientation angle or argon pressure was observed in the Al films. These results suggest that, under certain circumstances, shadowing effects and/or grain orientation (i.e., texture) competition during growth can give rise to lower …
Date: April 5, 1999
Creator: Baumann, F.H.; Gilmer, G.H.; O'Sullivan, P.L.; Sapjeta, J.; Torre, J.D. & Windt, D.L.
Object Type: Article
System: The UNT Digital Library
Epitaxial Growth of Yb<sub>2</sub>O<sub>3</sub> Buffer Layers on Biaxially Textured-Ni (100) Substrates by Sol-Gel Process (open access)

Epitaxial Growth of Yb<sub>2</sub>O<sub>3</sub> Buffer Layers on Biaxially Textured-Ni (100) Substrates by Sol-Gel Process

In order to develop an alternative buffer layer architecture using the sol-gel process to produce YBCO (YBa2Cu307+) coated conductors, Yb203 has been chosen as the candidate material. Buffer layers of fi03 were epitaxkdly grown on biaxially textured-Ni (100) substrates by the sol gel process for the first time. The ~03 precursor solution was prepared from an alkoxide sol-gel route in 2-xnetho~ethanol and was deposited on textured-Ni (100) substrates by either spin coating or dip coating methods. The amorphous film was then processed at 1160oC under flowing (96%)MH2(4%) gas mixture for one hour. The fi03 iihn exhibited a strong c-axis orientation on the Ni (100) substrates. The phi and omega scans indicated good in plane and out of plane orientations. The X-ray (222) pde figure showed a cube-on-cube epitaxy. High current YBCO films were grown on the Y&03 sol-gel buffered-Ni substrates.
Date: April 5, 1999
Creator: Beach, D. B.; Chirayil, T. G.; Christen, D. K.; Feenstra, R.; Goyal, A.; Kroeger, D. M. et al.
Object Type: Article
System: The UNT Digital Library
Environmental Justice Assessment for Transportation (open access)

Environmental Justice Assessment for Transportation

Application of Executive Order 12898 to risk assessment of highway or rail transport of hazardous materials has proven difficult; the location and conditions affecting the propagation of a plume of hazardous material released in a potential accident are unknown, in general. Therefore, analyses have only been possible in geographically broad or approximate manner. The advent of geographic information systems and development of software enhancements at Sandia National Laboratories have made kilometer-by-kilometer analysis of populations tallied by U.S. Census Blocks along entire routes practicable. Tabulations of total, or racially/ethnically distinct, populations close to a route, its alternatives, or the broader surrounding area, can then be compared and differences evaluated statistically. This paper presents methods of comparing populations and their racial/ethnic compositions using simple tabulations, histograms and Chi Squared tests for statistical significance of differences found. Two examples of these methods are presented: comparison of two routes and comparison of a route with its surroundings.
Date: April 5, 1999
Creator: Mills, G.S. & Neuhauser, K.S.
Object Type: Article
System: The UNT Digital Library
Self-Diffusion Along Step-Bottoms on Pt(111) (open access)

Self-Diffusion Along Step-Bottoms on Pt(111)

First-principles total energies of periodic vicinals are used to estimate barriers for Pt-adatom diffusion along straight and kinked steps on Pt(111), and around a corner where straight steps intersect. In all cases studied, hopping diffusion has a lower barrier than concerted substitution. In conflict with simulations of dendritic Pt island formation on Pt(111), hopping from a corner site to a step whose riser is a (111)-micro facet is predicted to be more facile than to one whose riser is a (100).
Date: April 5, 1999
Creator: Feibelman, Peter J.
Object Type: Article
System: The UNT Digital Library
Using emissivity-corrected thermal maps to locate deep structural defects in concrete bridge decks (open access)

Using emissivity-corrected thermal maps to locate deep structural defects in concrete bridge decks

Dual-band infrared (DBIR) thermal imaging is a promising, non-contact, nondestructive evaluation tool to evaluate the amount of deteriorated concrete on asphalt-covered bridge decks. We conducted proof-of-principle demonstrations to characterize defects in concrete structures which could be detected with DBIR thermal imaging. We constructed two identical concrete slabs with synthetic delaminations, e.g., 1/8-in. thick styrofoam squares, implanted just above the 2-in.-deep steel reinforcement bars. We covered one of the slabs with a 2-in. layer of asphalt. We mounted the DBIR cameras on a tower platform, to simulate the optics needed to conduct bridge-deck inspections from a moving vehicle. We detected 4-in. implants embedded in concrete and 9-in. implants embedded in asphalt-covered concrete. The midday (above-ambient) and predawn (below-ambient) delamination-site temperatures correlated with the implant sizes. Using DBIR image ratios, we enhanced thermal-contrast and removed emissivity-noise, e.g., from concrete compositional variations and clutter. Using the LLNL/VIEW code, we removed the asphalt thermal-gradient mask, to depict the 4-in. deep, 9-in. square, concrete implant size. We plan to image bridge deck defects, from a moving vehicle, for accurate estimations of the amount of deteriorated concrete impairing the deck integrity. Potential longterm benefits are affordable and reliable rehabilitation for asphalt-covered decks.
Date: April 5, 1995
Creator: Del Grande, N. K. & Durbin, P. F.
Object Type: Article
System: The UNT Digital Library
Chemical Bonding in Tl Cuprates Studied by X-Ray Photoemission (open access)

Chemical Bonding in Tl Cuprates Studied by X-Ray Photoemission

Epitaxial thin films of the Tl cuprate superconductors Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8}, Tl{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}, and TL{sub 0.78}Bi{sub 0.22}Ba{sub 0.4}Sr{sub 1.6}Ca{sub 2}Cu{sub 3}O{sub 9{minus}{delta}} are studied with x-ray photoemission spectroscopy. These data, together with previous measurements in this lab of Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} and TlBa{sub 2}CaCu{sub 2}O{sub 7{minus}{delta}}, comprise a comprehensive data set for a comparative study of Tl cuprates with a range of chemical and electronic properties. In the Cu 2p spectra, a larger energy separation between the satellite and main peaks (E{sub s}-E{sub m}) and a lower intensity ratio (I{sub s}/I{sub m}) are found to correlate with higher values of T{sub c}. Analysis of these spectra within a simple configuration interaction model suggests that higher values of T{sub c} are related to low values of the O 2p {r_arrow} Cu 3d charge transfer energy. In the O 1s region, a smaller bond length between Ba and Cu-O planar oxygen is found to correlate with a lower binding energy for the signal associated with Cu-O bonding, most likely resulting from the increased polarization screening by Ba{sup 2+} ions. For samples near optimum doping, maximum T{sub c} is observed to occur when the Tl 4f{sub …
Date: April 5, 1999
Creator: Lao, J.Y.; Overmyer, D.L.; Ren, Z.F.; Siegal, M.P.; Vasquez, R.P. & Wang, J.H.
Object Type: Article
System: The UNT Digital Library