Atomic Physics (open access)

Atomic Physics

None
Date: July 9, 1999
Creator: unknown
Object Type: Article
System: The UNT Digital Library
Bent solenoid simulations for the muon cooling experiment (open access)

Bent solenoid simulations for the muon cooling experiment

The muon collider captures pions using solenoidal fields. The pion are converted to muons as they are bunched in an RF phase rotation system. Solenoids are used to focus the muons as their emitance is reduced during cooling. Bent solenoids are used to sort muons by momentum. This report describes a bent solenoid system that is part of a proposed muon cooling experiment. The superconducting solenoid described in this report consists of a straight solenoid that is 1.8 m long, a bent solenoid that is 1.0 m to 1.3 m long and a second straight solenoid that is 2.6 m long. The bent solenoid bends the muons over an angle of 57.3 degrees (1 radian). The bent solenoid has a minor coil radius (to the center of the coil) that is 0.24 m and a major radius (of the solenoid axis) of 1.0 m. The central induction along the axis is 3.0 T There is a dipole that generates an induction of 0.51 T, perpendicular to the plane of the bend, when the induction on the bent solenoid axis is 3.0 T.
Date: July 9, 1999
Creator: Green, M. A.; Eyssa, Y. M.; Kenney, S.; Miller, J. R. & Prestemon, S.
Object Type: Article
System: The UNT Digital Library
Close Encounters of Asteroids and Comets to Planets (open access)

Close Encounters of Asteroids and Comets to Planets

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors find by numerical simulations that the elongated-potato shape that is characteristic of Earth-crossing asteroids (ECAs) is likely the result of previous close tidal encounters with Earth. Some meteoroids graze the atmosphere of Earth before returning to space (at reduced speed). They used a spherical atmospheric model to study such grazers to find the condition under which they are captured into gravitationally bound orbits around Earth. They find that for about every thousand iron asteroids that hit the Earth, one is captured into a gravitational-bound orbit. Some fraction of these captured objects will have their orbits stabilized for many revolutions by tidal encounters with the Moon and the sun. They have also studied how the damage produced by such grazing and near-grazing asteroids differs from that produced by asteroids that hit Earth more directly.
Date: July 9, 1999
Creator: Hills, J.G.; Goda, M.P. & Solem, J.C.
Object Type: Report
System: The UNT Digital Library
Corrosion Behavior of Plasma-Passivated Cu (open access)

Corrosion Behavior of Plasma-Passivated Cu

A new approach is being pursued to study corrosion in Cu alloy systems by using combinatorial analysis combined with microscopic experimentation (the Combinatorial Microlab) to determine mechanisms for copper corrosion in air. Corrosion studies are inherently difficult because of complex interactions between materials and environment, forming a multidimensional phase space of corrosion variables. The Combinatorial Microlab was specifically developed to address the mechanism of Cu sulfidation, which is an important reliability issue for electronic components. This approach differs from convention by focusing on microscopic length scales, the relevant scale for corrosion. During accelerated aging, copper is exposed to a variety of corrosive environments containing sulfidizing species that cause corrosion. A matrix experiment was done to determine independent and synergistic effects of initial Cu oxide thickness and point defect density. The CuO{sub x} was controlled by oxidizing Cu in an electron cyclotron resonance (ECR) O{sub 2} plasma, and the point defect density was modified by Cu ion irradiation. The matrix was exposed to 600 ppb H{sub 2}S in 65% relative humidity air atmosphere. This combination revealed the importance of oxide quality in passivating Cu and prevention of the sulfidizing reaction. A native oxide and a defect-laden ECR oxide both react at …
Date: July 9, 1999
Creator: Barbour, J. C.; Braithwaite, J. W.; Son, K.-A.; Sullivan, J. P.; Missert, N, & Sorensen, N. R.
Object Type: Article
System: The UNT Digital Library
Energy Matters, July 1999 (open access)

Energy Matters, July 1999

This issue of Energy Matters focuses on selling an energy-efficient project to management. There are also articles on combined heat and power systems, inspecting steam traps for efficient system, root cause failure analysis on AC induction motors, and performance optimization tips.
Date: July 9, 1999
Creator: Erickson, E.
Object Type: Book
System: The UNT Digital Library
Federal Land Management: Information on Usage of the Antiquities Act (open access)

Federal Land Management: Information on Usage of the Antiquities Act

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on how the Antiquities Act of 1906 has been used since its passage, focusing on: (1) the monuments that have been established under the act; and (2) a comparison of the requirements, if any, for environmental documentation and public participation, and of the processes, if any, for facilitating congressional oversight found in the act and in three other pieces of legislation--the National Environmental Policy Act of 1969 (NEPA), the Federal Land Policy and Management Act of 1976 (FLPMA), and the National Forest Management Act of 1976 (NFMA)."
Date: July 9, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
HLW Salt Disposition Alternatives Identification Preconceptual Phase I Summary Report (Including Attachments) (open access)

HLW Salt Disposition Alternatives Identification Preconceptual Phase I Summary Report (Including Attachments)

The purpose of this report is to summarize the process used by the Team to systematically develop alternative methods or technologies for final disposition of HLW salt. Additionally, this report summarizes the process utilized to reduce the total list of identified alternatives to an ''initial list'' for further evaluation. This report constitutes completion of the team charter major milestone Phase I Deliverable.
Date: July 9, 1999
Creator: Piccolo, S. F.
Object Type: Report
System: The UNT Digital Library
HLW Salt Disposition Alternatives Preconceptual Phase II Summary Report (open access)

HLW Salt Disposition Alternatives Preconceptual Phase II Summary Report

The purpose of the report is to summarize the process used to identify the Short List alternatives that will be evaluated during Phase III and to document the results of the selection process. The Phase III evaluation will result in the determination of the preferred alternative(s) to be used for final disposition of the HLW salt to a permitted waste form.
Date: July 9, 1999
Creator: Piccolo, S.F.
Object Type: Report
System: The UNT Digital Library
Infrastructure, Technology and Applications of Micro-Electro-Mechanical Systems (MEMS) (open access)

Infrastructure, Technology and Applications of Micro-Electro-Mechanical Systems (MEMS)

A review is made of the infrastructure, technology and capabilities of Sandia National Laboratories for the development of micromechanical systems. By incorporating advanced fabrication processes, such as chemical mechanical polishing, and several mechanical polysilicon levels, the range of micromechanical systems that can be fabricated in these technologies is virtually limitless. Representative applications include a micro-engine driven mirror, and a micromachined lock. Using a novel integrated MEMS/CMOS technology, a six degree-of-freedom accelerometer/gyroscope system has been designed by researchers at U.C. Berkeley and fabricated on the same silicon chip as the CMOS control circuits to produce an integrated micro-navigational unit.
Date: July 9, 1999
Creator: Allen, J. J.; Jakubczak, J. F.; Krygowski, T. W.; Miller, S. L.; Montague, S.; Rodgers, M. S. et al.
Object Type: Article
System: The UNT Digital Library
Intercity Passenger Rail: Amtrak's Progress in Improving Its Financial Condition Has Been Mixed (open access)

Intercity Passenger Rail: Amtrak's Progress in Improving Its Financial Condition Has Been Mixed

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO followed up on its report on Amtrak's financial performance, focusing on: (1) Amtrak's overall financial performance in fiscal year (FY) 1998; (2) the prospects for Amtrak to meet its financial goals for operating self-sufficiency outlined in its most recent strategic business plan; and (3) the extent to which current and anticipated federal funding and recently enacted legislative reforms aimed at helping Amtrak better control its costs are likely to help improve its financial condition."
Date: July 9, 1999
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Measurement of the B Quark Fragmentation Function in Z{sup 0} Decays (open access)

Measurement of the B Quark Fragmentation Function in Z{sup 0} Decays

We present preliminary results of a new measurement of the inclusive b quark fragmentation function in Z{sup 0} decays using a novel kinematic B hadron energy reconstruction technique. The measurement is performed using 150,000 hadronic Z{sup 0} events recorded in the SLD experiment at SLAC between 1996 and 1997. The small and stable SLC beam spot and the CCD-based vertex detector are used to reconstruct topological B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used in this technique. We measure the B energy with good efficiency and resolution over the full kinematic range. We compare the measured scaled B hadron energy distribution with several functional forms of the B hadron energy distribution and predictions of several models of b quark fragmentation. Several functions are excluded by the data. The average scaled energy of the weakly decaying B hadron is measured to be x{sub B} = 0.714 {+-} 0.005 (stat) {+-} 0.007 (syst) {+-} 0.002 (model) (preliminary).
Date: July 9, 1999
Creator: Dong, Danning
Object Type: Report
System: The UNT Digital Library
Measurement of the Probability for Gluon Splitting into b{bar b} in Z{sup 0} Decays (open access)

Measurement of the Probability for Gluon Splitting into b{bar b} in Z{sup 0} Decays

We present a preliminary measurement of the rate of gluon splitting into bottom quarks, g {r_arrow} b{bar b}, in hadronic Z{sup 0} decays collected by SLD between 1996 and 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary flavor. 4-jet events were identified, and a topological vertex-mass technique was applied to each jet in order to identify b or {bar b} jets. The upgraded CCD based vertex detector gives very high B-tagging efficiency, especially for B hadrons of the low energies typical of this process. The two most nearly collinear b/{bar b} jets were tagged as originating from g {r_arrow} b{bar b}. We measured the rate of secondary b/{bar b} production per hadronic event, g{sub b{bar b}}, to be (3.07 {+-} 0.71(stat.) {+-} 0.66(syst.)) x 10{sup {minus}3} (preliminary).
Date: July 9, 1999
Creator: Muller, David
Object Type: Report
System: The UNT Digital Library
Mechanical Properties of Cellular Materials (open access)

Mechanical Properties of Cellular Materials

The authors calculated the stress-strain relation for elastomeric foam from an ab initio theory, which shows that the plateau and densification regions should be described by a hyperbola. The theory seems to agree reasonably well with experiment.
Date: July 9, 1999
Creator: Solem, J. C. & Dienes, J. K.
Object Type: Report
System: The UNT Digital Library
Modeling and Imaging Flexural Plate Wave Devices (open access)

Modeling and Imaging Flexural Plate Wave Devices

Sandia National Laboratories is developing a new form of flexural plate wave device (FPW) for sensor applications. In this device, Lorentz forces cause out of plane vibrations in a silicon nitride membrane. Current induced in transducer lines on the membrane provides information about the amplitude and phase of these surface vibrations. By tracking the large amplitude vibrations that occur at resonant frequencies, it is possible to infer information about loading on the membrane. In fabricating FPWs, it is important to understand the impact that minor defects can have on operation. Through modeling and testing, they are developing resilient designs that provide large amplitude signals with a high tolerance to defects. A finite element model has been developed to perform design trade-off studies, and results from the model are being verified with a unique measurement system that can image Angstrom scale displacements at vibrational frequencies up to 800 kHz. Results from FPW modeling and imaging efforts are presented in this paper.
Date: July 9, 1999
Creator: Adkins, D. R.; Butler, M. A.; Chu, A. S. & Schubert, W. K.
Object Type: Article
System: The UNT Digital Library
Molecular Dynamics Simulation of the Structure and Properties of Lithium Phosphate Glasses (open access)

Molecular Dynamics Simulation of the Structure and Properties of Lithium Phosphate Glasses

A new forcefield model was developed for the computer simulation of phosphate materials that have many important applications in the electronics and biomedical industries. The model provides a fundamental basis for the evaluation of phosphate glass structure and thermodynamics. Molecular dynamics simulations of a series of lithium phosphate glass compositions were performed using the forcefield model. A high concentration of three-membered rings (P{sub 3}O{sub 3}) occurs in the glass of intermediate composition (0.2 Li{sub 2}O {center_dot} 0.8P{sub 2}O{sub 5}) that corresponds to the minimum in the glass transition temperature curve for the compositional series. Molecular orbital calculations of various phosphate ring clusters indicate an increasing stabilization of the phosphate ring structure going from two- to four-membered rings.
Date: July 9, 1999
Creator: Liang, J-J; Cygan, R.T. & Alam, T.M.
Object Type: Article
System: The UNT Digital Library
Neutrino Physics at Fermilab (open access)

Neutrino Physics at Fermilab

The Liquid Scintillator Neutrino Detector (LSND), located at the LANSCE (formerly LAMPF) linear accelerator at Los Alamos National Laboratory, has seen evidence for the oscillation of neutrinos, and hence neutrino mass. That discovery was the impetus for this LDRD project, begun in 1996. The goal of this project was to define the appropriate technologies to use in a follow up experiment and to set in place the requirements for such an experiment.
Date: July 9, 1999
Creator: Federspiel, F.; Garvey, G.; Louis, W.C.; Mills, G.B.; Tayloe, R.; Sandberg, V. et al.
Object Type: Report
System: The UNT Digital Library
Nuclear Futures Analysis and Scenario Building (open access)

Nuclear Futures Analysis and Scenario Building

This LDRD project created and used advanced analysis capabilities to postulate scenarios and identify issues, externalities, and technologies associated with future ''things nuclear''. ''Things nuclear'' include areas pertaining to nuclear weapons, nuclear materials, and nuclear energy, examined in the context of future domestic and international environments. Analysis tools development included adaptation and expansion of energy, environmental, and economics (E3) models to incorporate a robust description of the nuclear fuel cycle (both current and future technology pathways), creation of a beginning proliferation risk model (coupled to the (E3) model), and extension of traditional first strike stability models to conditions expected to exist in the future (smaller force sizes, multipolar engagement environments, inclusion of actual and latent nuclear weapons (capability)). Accomplishments include scenario development for regional and global nuclear energy, the creation of a beginning nuclear architecture designed to improve the proliferation resistance and environmental performance of the nuclear fuel cycle, and numerous results for future nuclear weapons scenarios.
Date: July 9, 1999
Creator: Arthur, E. D.; Beller, D.; Canavan, G. H.; Krakowski, R. A.; Peterson, P. & Wagner, R. L.
Object Type: Report
System: The UNT Digital Library
Physical Protection System Upgrades - Optimizing for Performance and Cost (open access)

Physical Protection System Upgrades - Optimizing for Performance and Cost

CPA--Cost and Performance Analysis--is an architecture that supports analysis of physical protection systems and upgrade options. ASSESS (Analytic System and Software for Evaluating Security Systems), a tool for evaluating performance of physical protection systems, currently forms the cornerstone for evaluating detection probabilities and delay times of the system. Cost and performance data are offered to the decision-maker at the systems level and to technologists at the path-element level. A new optimization engine has been attached to the CPA methodology to automate analyses of many combinations (portfolios) of technologies. That engine controls a new analysis sequencer that automatically modifies ASSESS PPS files (facility descriptions), automatically invokes ASSESS Outsider analysis and then saves results for post-processing. Users can constrain the search to an upper bound on total cost, to a lower bound on level of performance, or to include specific technologies or technology types. This process has been applied to a set of technology development proposals to identify those portfolios that provide the most improvement in physical security for the lowest cost to install, operate and maintain at a baseline facility.
Date: July 9, 1999
Creator: Bouchard, Ann M. & Hicks, Mary Jane
Object Type: Article
System: The UNT Digital Library
A Preliminary Direct Measurement of the Parity-Violating Coupling of the Z{sup 0} to Strange Quarks, A{sub s} (open access)

A Preliminary Direct Measurement of the Parity-Violating Coupling of the Z{sup 0} to Strange Quarks, A{sub s}

We present an updated direct measurement of the parity-violating coupling of the Z{sup 0} to strange quarks, A{sub s}, derived from the full SLD data sample of approximately 550,000 hadronic decays of Z{sup 0} bosons produced with a polarized electron beam and recorded by the SLD experiment at SLAC between 1993 and 1998. Z{sup 0} {r_arrow} s{bar s} events are tagged by the presence in each event hemisphere of a high-momentum K{sup {+-}}, K{sub s} or {Lambda}{sup 0}/{bar {Lambda}}{sup 0} identified using the Cherenkov Ring Imaging Detector and/or a mass tag. The CCD vertex detector is used to suppress the background from heavy-flavor events. The strangeness of the tagged particle is used to sign the event thrust axis in the direction of the initial s quark. The coupling A{sub s} is obtained directly from a measurement of the left-right-forward-backward production asymmetry in polar angle of the tagged s quark. The background from u{bar u} and d{bar d} events is measured from the data, as is the analyzing power of the method for s{bar s} events. We measure: A{sub s} = 0.85 {+-} 0.06(stat.) {+-} 0.07(syst.)(preliminary).
Date: July 9, 1999
Creator: Muller, David
Object Type: Report
System: The UNT Digital Library
Production of Charged {pi}{sup {+-}}, {Kappa}{sup {+-}} and p/p in Hadronic Z{sup 0} Decays (open access)

Production of Charged {pi}{sup {+-}}, {Kappa}{sup {+-}} and p/p in Hadronic Z{sup 0} Decays

We have updated our results on identified charged hadron production using the full SLD data sample of 550,000 hadronic Z{sup 0} decays taken between 1993 and 1998. The SLD Cherenkov Ring Imaging Detector allows the identification of clean samples of charged pions, kaons and protons over a wide momentum range, providing precise tests of perturbative QCD calculations and of fragmentation models. We have studied flavor-inclusive Z{sup 0} decays, as well as decays into light, c and b flavors, selected using the SLD vertex detector. In addition we have updated our comparison of hadron and antihadron production in light quark (rather than antiquark) jets, selected using the high SLC electron beam polarization. Differences between hadron and antihadron production at high momentum fraction provide precise measurements of leading particle production and new, stringent tests of fragmentation models.
Date: July 9, 1999
Creator: Muller, David
Object Type: Report
System: The UNT Digital Library
Refrigeration options for the Advanced Light Source Superbend Dipole Magnets (open access)

Refrigeration options for the Advanced Light Source Superbend Dipole Magnets

The 1.9 GeV Advance Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL) produces photons with a critical energy of about 3.1 kev at each of its thirty-six 1.3 T gradient bending magnets. It is proposed that at three locations around the ring the conventional gradient bending magnets be replaced with superconducting bending magnets with a maximum field of 5.6 T. At the point where the photons are extracted, their critical energy will be about 12 keV. In the beam lines where the SuperBend superconducting magnets are installed, the X ray brightness at 20 keV will be increased over two orders of magnitude. This report describes three different refrigeration options for cooling the three SuperBend dipoles. The cooling options include: (1) liquid helium and liquid nitrogen cryogen cooling using stored liquids, (2) a central helium refrigerator (capacity 70 to 100 W) cooling all of the SuperBend magnets, (3) a Gifford McMahon (GM) cryocooler on each of the dipoles. This paper describes the technical and economic reasons for selecting a small GM cryocooler as the method for cooling the SuperBend dipoles on the LBNL Advanced Light Source.
Date: July 9, 1999
Creator: Green, M. A.; Hoyer, E. H.; Schlueter, R. D.; Taylor, C. E.; Zbasnik, J. & Wang, S. T.
Object Type: Article
System: The UNT Digital Library
Structure and Dynamics of Quasi-Ordered Systems (open access)

Structure and Dynamics of Quasi-Ordered Systems

The functionality of many materials of both fundamental and technological interest is often critically dependent on the nature and extent of any disorder that may be present. In addition, it is often difficult to understand the nature of disorder in quite well ordered systems. There is therefore an urgent need to develop better tools, both experimental and computational, for the study of such quasi-ordered systems. To this end, the authors have used neutron diffraction studies in an attempt to locate small metal clusters or molecules randomly distributed inside microporous catalytic materials. Specifically, they have used pair distribution function (PDF) analysis, as well as inelastic neutron scattering (INS) spectroscopy, to study interactions between adsorbate molecules and a microporous matrix. They have interfaced these experimental studies with computations of PDF analysis as well as modeling of the dynamics of adsorbates. These techniques will be invaluable in elucidating the local structure and function of many of these classes of materials.
Date: July 9, 1999
Creator: Eckert, Juergen; Redondo, Antonio; Henson, Neil J.; Wang, Wanshu & Hay, P. Jeffrey
Object Type: Report
System: The UNT Digital Library
A Study of Correlations Between Identified Charged Hadrons in Hadronic Z{sup 0} Decays (open access)

A Study of Correlations Between Identified Charged Hadrons in Hadronic Z{sup 0} Decays

We present a preliminary study of correlations in rapidity between pairs of identified charged pions, kaons and protons using the entire SLD data sample of 550,000 hadronic Z{sup 0} decays. Short range charge correlations are observed between all combinations of these hadron species, indicating local conservation of quantum numbers and charge ordering in the jet fragmentation process. The rapidity range of this effect is found to be independent of particle momentum. A strong long-range K{sup +}-K{sup {minus}} correlation is observed at high-momentum and weaker long-range {pi}{sup +}-{pi}{sup {minus}}, {pi}{sup +}-K{sup {minus}} and p-K{sup {minus}} and p{bar p} correlations are observed in light flavor events, providing new information on leading particle production in u, d and s jets. The long-range correlations observed in c{bar c} and b{bar b} events are markedly different and consistent with expectations based on known decay properties of the leading heavy hadrons. In addition, the SLC electron beam polarization is used to tag the quark hemisphere in each event, allowing the first study of rapidities signed such that positive rapidity is along the quark rather than antiquark direction. Distributions of ordered differences in signed rapidity between pairs of particles provide a direct probe of quantum number ordering …
Date: July 9, 1999
Creator: Muller, David
Object Type: Report
System: The UNT Digital Library
Study of the Structure of e{sup +}e{sup {minus}} {r_arrow} b{bar b}g Events and Improved Limits on the Anomalous Chromomagnetic Coupling of the b-Quark (open access)

Study of the Structure of e{sup +}e{sup {minus}} {r_arrow} b{bar b}g Events and Improved Limits on the Anomalous Chromomagnetic Coupling of the b-Quark

The structure of e{sup +}e{sup {minus}} {r_arrow} b{bar b}g events was studied using Z{sup 0} decays recorded in the SLD experiment at SLAC. Three-jet final states were selected and the CCD-based vertex detector was used to identify two of the jets as b or {bar b}. Distributions of the gluon energy and polar angle were measured over the full kinematic range, and compared with perturbative QCD predictions. The energy distribution is potentially sensitive to an anomalous b chromomagnetic moment {kappa}. We measured {kappa} to be consistent with zero and set limits on its value, {minus}0.11 < {kappa} < 0.08 at 95% c.l. (preliminary).
Date: July 9, 1999
Creator: Muller, David
Object Type: Report
System: The UNT Digital Library