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Electron positron factories (open access)

Electron positron factories

In this paper, we will first indicate the key issues in designing a B-factory and a {phi}-factory, and illustrate the approaches that are being followed to address them. In general, reaching the B-factory parameter regime offers the most challenges, so we will emphasize it here. Then we will consider an extrapolation of our present understanding of collider performance and assess the maximum luminosity that could be anticipated. To reach extremely high luminosity, it may be necessary to consider possibilities beyond the scope of standard'' approaches to collider design; a few illustrative examples are outlined. For both the present designs and the extrapolated parameters, R D activities in a few key areas are required; these areas are discussed in this paper also.
Date: December 1, 1990
Creator: Zisman, M. S.; Chattopadhyay, S.; Garren, A. A.; Lambertson, G. (Lawrence Berkeley Lab., CA (United States)); Bloom, E.; Corbett, W. J. et al.
System: The UNT Digital Library
Pattern recognition in gamma-gamma coincidence data sets (open access)

Pattern recognition in gamma-gamma coincidence data sets

Considerable amounts of tedious labor are required to manually scan high-resolution 1D slices of two dimensional {gamma}-{gamma} coincident matrices for relevant and exciting structures. This is particularly true when the interesting structures are of weak intensity. We are working on automated search methods for the detection of rotational band structures in the full 2D space using pattern recognition techniques. For nominal sized data sets (1024{times}1024), however, these techniques only become computationally feasible through the use of Fourier Transform methods. Furthermore the presentation of data matrices as images rather than series of 1D spectra has been shown to be useful. In this paper we will present the data manipulation techniques we have developed.
Date: October 1, 1990
Creator: Manatt, D. R.; Barnes, F. L.; Becker, J. A.; Candy, J. V.; Henry, E. A. (Lawrence Livermore National Lab., CA (United States)) & Brinkman, M. J. (Rutgers--the State Univ., New Brunswick, NJ (United States))
System: The UNT Digital Library
Thermal vacuum life test facility for radioisotope thermoelectric generators (open access)

Thermal vacuum life test facility for radioisotope thermoelectric generators

In the late 1970's, the Department of Energy (DOE) assigned Monsanto Research Corporation, Mound Facility, now operated by EG G Mound Applied Technologies, the responsibility for assembling and testing General Purpose Heat Source (GPHS) radioisotope thermoelectric generators (RTGs). Assembled and tested were five RTGs, which included four flight units and one non-flight qualification unit. Figure 1 shows the RTG, which was designed by General Electric AstroSpace Division (GE/ASD) to produce 285 W of electrical power. A detailed description of the processes for RTG assembly and testing is presented by Amos and Goebel (1989). The RTG performance data are described by Bennett, et al. (1986). The flight units will provide electrical power for the National Aeronautics and Space Administration's (NASA) Galileo mission to Jupiter (two RTGs) and the joint NASA/European Space Agency (ESA) Ulysses mission to study the polar regions of the sun (one RTG). The remaining flight unit will serve as the spare for both missions, and a non-flight qualification unit was assembled and tested to ensure that performance criteria were adequately met. 4 refs., 3 figs.
Date: January 1, 1990
Creator: Deaton, R. L.; Goebel, C. J. & Amos, W. R.
System: The UNT Digital Library
High-brightness injectors for hadron colliders (open access)

High-brightness injectors for hadron colliders

The counterrotating beams in collider rings consist of trains of beam bunches with N{sub B} particles per bunch, spaced a distance S{sub B} apart. When the bunches collide, the interaction rate is determined by the luminosity, which is defined as the interaction rate per unit cross section. For head-on collisions between cylindrical Gaussian beams moving at speed {beta}c, the luminosity is given by L = N{sub B}{sup 2}{beta}c/4{pi}{sigma}{sup 2}S{sub B}, where {sigma} is the rms beam size projected onto a transverse plane (the two transverse planes are assumed identical) at the interaction point. This beam size depends on the rms emittance of the beam and the focusing strength, which is a measure of the 2-D phase-space area in each transverse plane, and is defined in terms of the second moments of the beam distribution. Our convention is to use the rms normalized emittance, without factors of 4 or 6 that are sometimes used. The quantity {tilde {beta}} is the Courant-Synder betatron amplitude function at the interaction point, a characteristic of the focusing lattice and {gamma} is the relativistic Lorentz factor. Achieving high luminosity at a given energy, and at practical values of {tilde {beta}} and S{sub B}, requires a large …
Date: January 1, 1990
Creator: Wangler, T. P.
System: The UNT Digital Library
Creep strength of niobium alloys, Nb-1%Zr and PWC-11 (open access)

Creep strength of niobium alloys, Nb-1%Zr and PWC-11

A study is being conducted at NASA Lewis Research Center to determine the feasibility of using a carbide particle strengthened Nb-1% Zr base alloy to meet the anticipated temperature and creep resistance requirements of proposed near term space power systems. In order to provide information to aid in the determination of the suitability of the PWC-11 alloy as an alternative to Nb-1% Zr in space power systems this study investigated (1) the long-time high-vacuum creep behavior of the PWC-11 material and the Nb-1% Zr alloy, (2) the effect of prior stress-free thermal aging on this creep behavior, (3) the effect of electron beam (EB) welding on this creep behavior, and (4) the stability of creep strengthening carbide particles. 14 refs., 5 figs., 2 tabs.
Date: January 1, 1990
Creator: Titran, R.H.
System: The UNT Digital Library
Liquid and solid Ga and Bi studies with a variable energy positron beam (open access)

Liquid and solid Ga and Bi studies with a variable energy positron beam

The diffusion length of positrons has been measured in liquid and solid gallium and bismuth using a vertical positron beam. For Ga our results indicate a drop in the diffusion length from 1200 (100) {Angstrom} to 30 (5) {Angstrom} as the sample melts, as the temperature is increased there is a surprising increase in the diffusion length. At the melting point the annihilation parameter S in the bulk increases sharply, and stays constant with temperature, which indicates that vacancy size trapping centers exist in the liquid. For Bi, the diffusion length drops in the liquid from 500 {Angstrom} to 200 {Angstrom}, and increases slightly as the temperature is increased. This drop is interpreted in terms of increased scattering with Bi ions. A small change is observed in bulk S, indicating no trapping of positrons as the sample melts. This behaviour, which is so different in these two metals, indicates the sensitivity of positrons to the liquid structure. 6 refs., 2 figs.
Date: January 1, 1990
Creator: Gramsch, E.; Lynn, K.G.; Throwe, J. & Kanazawa, I.
System: The UNT Digital Library
Development of microstructures with improved cryogenic toughness through local variations in stress state: Aluminum-lithium alloys (open access)

Development of microstructures with improved cryogenic toughness through local variations in stress state: Aluminum-lithium alloys

Microstructurally-induced changes in the local stress state (triaxial constraint) and their effect on fracture-toughness behavior are examined at ambient and cryogenic temperatures in an Al-Li-Cu-Zr alloy, processed in the form of 12.7 mm-thick naturally laminated'' plate containing aligned-weak interfaces and 1.6 mm-thin unlaminated sheet. It is shown that marked improvements in long-transverse (L-T) toughness can be achieved in the plate material at cryogenic temperatures by promoting through-thickness delamination along these interfaces, which relaxes local constraint and promotes a fracture-mode transition from global plane strain to local plane stress. Conversely, in thin sheet material, the absence of such interface delamination leads to a reduction in toughness with decrease in temperature, consistent with the greater degree of crack-tip constraint. 17 refs., 4 figs., 1 tab.
Date: April 1, 1990
Creator: Venkateswara Rao, K. T. & Ritchie, R. O.
System: The UNT Digital Library
Multi-beam injector development at LBL (open access)

Multi-beam injector development at LBL

LBL is developing a multi-beam injector that will be used for scaled accelerator experiments related to Heavy Ion Fusion. The device will produce sixteen 0.5 Amp beams of C+ at 2 MeV energy. The carbon arc source has been developed to the point where the emittance is within a factor of four of the design target. Modelling of the source behavior to find ways to reduce the emittance is discussed. Source lifetime and reliability is also of paramount importance to us and data regarding the lifetime and failure modes of different source configurations is discussed. One half of the accelerating column has been constructed and tested at high voltage. One beam experiments in this half column are underway. The second half of the column is being built and the transition 2 MV experiments should begin soon. In addition to beam and source performance we also discuss the controls for the injector and the electronics associated with the source and current injection. 3 refs., 2 figs.
Date: June 1, 1990
Creator: Rutkowski, H. L.; Faltens, A.; Brodzik, D. A.; Johnson, R. M.; Pike, C. D.; Vanecek, D. L. (Lawrence Berkeley Lab., CA (United States)) et al.
System: The UNT Digital Library
Basic features of coherent radiation generated by relativistic charge bunches (open access)

Basic features of coherent radiation generated by relativistic charge bunches

Radiation generated by relativistic charges can be analyzed and described in exquisite detail. One reason that such detailed analysis is possible is because the phases of radiated photons often are determined completely by the initial conditions of the relativistic charges and the radiating system. The phase relationships between the initial charges and the radiated photons represent coherence in the emitted radiation. A previous paper described how this coherence could affect the spatial and spectral distributions of radiation generated by a single charge in a periodic radiator. The present paper discusses a complementary issue; namely, how the temporal shape of a relativistic charge bunch can emphasize specific features of the radiation generated at a single interaction site. 3 refs., 4 figs.
Date: November 1, 1990
Creator: Moran, M. J. & Chang, B.
System: The UNT Digital Library
The search for low photodesorption coatings (open access)

The search for low photodesorption coatings

Low photo desorption (PSD) from surfaces of vacuum chambers increases the beam lifetime and reduces the cost of the pumping system of any storage ring. In compact rings where all radiated power ({approximately}10 kW) is incident on a few meters only, low PSD and good thermal conductivity of photon absorbers are of particular importance. An experimental chamber in which one meter long bars can be exposed to white photon beam with 500 eV critical energy has been built and installed on the U10B beamline in the VUV ring at the NSLS. Several reference bars made of high purity copper and a TiN coating on copper have been measured. Subsequent runs will include gold coating on copper, aluminum (200{degree}C baked), diamond coating on copper and uncoated beryllium bars. In this paper the desorption coefficients will be measured and compared. 6 refs., 4 figs.
Date: January 1, 1990
Creator: Foerster, C.L. & Korn, G.
System: The UNT Digital Library
Complex availability problems solved with simulation (open access)

Complex availability problems solved with simulation

System owners and operators are increasingly emphasizing the actual amount of time equipment is capable of performing its intended function. For military systems, added complexity, longer service life requirements, reduced periodic maintenance, and less frequent checkouts are increasing system availability requirements. However, these factors compound the difficulty in estimating the system's true availability. With dormant or semi-dormant systems, the amount of time a system appears'' available may differ form the real'' availability. The difference in real'' and apparent'' availability is often the result of a transition from an operational but dormant state to an inoperational but dormant state. The major contributions from this research are: the development of the concept of complex'' availability that applies to systems which combine two or more elements of instantaneous, mission system, or steady-state availability; and the development of modeling technique to estimate the real'' availability for a system which involves complex'' availability. 28 refs., 2 figs.
Date: January 1, 1990
Creator: Schroeder, G.J.; Johnson, M.M. (Los Alamos National Lab., NM (USA) & South Dakota School of Mines and Technology, Rapid City, SD (USA))
System: The UNT Digital Library
Status of the Virginia Power/DOE Cooperative Cask Testing/Demonstration Program: A video presentation (open access)

Status of the Virginia Power/DOE Cooperative Cask Testing/Demonstration Program: A video presentation

This paper is documentation of a video presentation and provides a brief summary of the Virginia power/US Department of Energy Cooperative Cask Testing/Demonstration Program. The program consists of two phases. The first phase has been completed and involved the unlicensed performance testing (heat transfer and shielding) of three metal spent fuel storage casks at the federally owned Idaho National Engineering Laboratory. The second phase is ongoing and consists of licensed demonstrations of standard casks from two different vendors and of one or two enhanced capacity casks. 6 refs., 1 tab.
Date: January 1, 1990
Creator: McKinnon, M.A.; Creer, J.M. (Pacific Northwest Lab., Richland, WA (USA)) & Collantes, C.E. (Department of Energy, Richland, WA (USA). Richland Operations Office)
System: The UNT Digital Library
Resonator design for a visible wavelength free-electron laser (*) (open access)

Resonator design for a visible wavelength free-electron laser (*)

Design requirements for a visible wavelength free-electron laser being developed at the Accelerator Test Facility at Brookhaven National Laboratory are presented along with predictions of laser performance from 3-D numerical simulations. The design and construction of the optical resonator, its alignment and control systems are also described. 15 refs., 8 figs., 4 tabs.
Date: January 1, 1990
Creator: Bhowmik, A.; Lordi, N. (Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.); Ben-Zvi, Ilan & Gallardo, J. (Brookhaven National Lab., Upton, NY (United States))
System: The UNT Digital Library
Fatigue-crack propagation in aluminum-lithium alloys processed by power and ingot metallurgy (open access)

Fatigue-crack propagation in aluminum-lithium alloys processed by power and ingot metallurgy

Fatigue-crack propagation behavior in powder-metallurgy (P/M) aluminum-lithium alloys, namely, mechanically-alloyed (MA) Al-4.0Mg-1.5Li-1.1C-0.80{sub 2} (Inco 905-XL) and rapid-solidification-processed (RSP) Al-2.6Li-1.0Cu-0.5Mg-0.5Zr (Allied 644-B) extrusions, has been studied, and results compared with data on an equivalent ingot-metallurgy (I/M) Al-Li alloy, 2090-T81 plate. Fatigue-crack growth resistance of the RSP Al-Li alloy is found to be comparable to the I/M Al-Li alloy; in contrast, crack velocities in MA 905-XL extrusions are nearly three orders of magnitude faster. Growth-rate response in both P/M Al-Li alloys, however, is high anisotropic. Results are interpreted in terms of the microstructural influence of strengthening mechanism, slip mode, grain morphology and texture on the development of crack-tip shielding from crack-path deflection and crack closure. 14 refs., 7 figs., 2 tabs.
Date: April 1, 1990
Creator: Venkateswara Rao, K.T.; Ritchie, R.O. (Lawrence Berkeley Lab., CA (United States)); Kim, N.J. (Pohang Inst. of Science and Technology (Korea, Republic of)) & Pizzo, P.P. (San Jose State Univ., CA (United States))
System: The UNT Digital Library
Excess transit time as a function of burst current in an exploding bridgewire detonator (open access)

Excess transit time as a function of burst current in an exploding bridgewire detonator

Transit time, the time from bridgewire burst until breakout of detonation from the output pellet of an exploding bridgewire detonator, was measured as a function of burst current. From this data, in conjunction with known equations for run distance versus pressure, unreacted explosive Hugoniots, and detonation properties of the initial pressing pellet, the run distance in the initial pressing explosive pellet and shock pressure from the exploding bridgewire were determined, both as a function of burst current.
Date: January 1, 1990
Creator: Cooper, P.W.; Owenby, R.N. & Stofleth, J.H.
System: The UNT Digital Library
An introduction to baryon violation in standard electroweak theory (open access)

An introduction to baryon violation in standard electroweak theory

I shall begin with a qualitative overview of the anomaly and B violation at zero and non-zero temperature, demonstrating how these processes may be understood on the back of an envelope. Then I shall discuss a part of the formalism necessary for doing calculations in more detail. Specifically, B violation is related to various solutions to the Euclidean equations of motion; instantons, sphalerons, and calorons (also called periodic instantons). The applicability of the various solutions may be understood by analogies with elementary quantum mechanics problems. Finally, I shall touch upon the computation of high-energy B violation mentioned above. 29 refs., 11 figs.
Date: December 1, 1990
Creator: Arnold, P.B.
System: The UNT Digital Library
Quench propagation in the SSC dipole magnets (open access)

Quench propagation in the SSC dipole magnets

The effects of quench propagation are modeled in 40mm and 50mm diameter collider dipole magnet designs. A comparative study of the cold diode (passive) and quench heater (active) protection schemes will be presented. The SSCQ modeling program accurately simulates the axial quench velocity and uses phenomenological time delays for turn-to-turn transverse propagation. The axial quench velocity is field dependent and consequently, each conductor's quench profile is tracked separately. No symmetry constraints are employed and the distribution of the temperatures along the conductor differs from the adiabatic approximation. A single magnet has a wide margin of self protection which suggests that passive protection schemes must be considered. 6 refs., 3 figs., 1 tab.
Date: September 1, 1990
Creator: Lopez, G. & Snitchler, G.
System: The UNT Digital Library
J/. psi. and. Upsilon. production at CDF (open access)

J/. psi. and. Upsilon. production at CDF

Characteristics of J/{psi} and {Upsilon} produced at the Tevatron and detected in the dimuon channel at CDF are reviewed. The masses of the J/{psi} and {Upsilon} are measured to be 3.096 {plus minus} 0.001 GeV/c{sup 2} and 9.469 {plus minus} 0.010 GeV/c{sup 2} respectively. These mass measurements are used to determine the systematic uncertainty on the momentum scale in the central tracking chamber. 2 refs., 14 figs.
Date: January 1, 1990
Creator: Liss, T. (Illinois Univ., Urbana, IL (USA))
System: The UNT Digital Library
Accelerator-based intense neutron source for materials R D (open access)

Accelerator-based intense neutron source for materials R D

Accelerator-based neutron sources for R D of materials in nuclear energy systems, including fusion reactors, can provide sufficient neutron flux, flux-volume, fluence and other attractive features for many aspects of materials research. The neutron spectrum produced from the D-Li reaction has been judged useful for many basic materials research problems, and to be a satisfactory approximation to that of the fusion process. The technology of high-intensity linear accelerators can readily be applied to provide the deuteron beam for the neutron source. Earlier applications included the Los Alamos Meson Physics Facility and the Fusion Materials Irradiation Test facility prototype. The key features of today's advanced accelerator technology are presented to illustrate the present state-of-the-art in terms of improved understanding of basic physical principles and engineering technique, and to show how these advances can be applied to present demands in a timely manner. These features include how to produce an intense beam current with the high quality required to minimize beam losses along the accelerator and transport system that could cause maintenance difficulties, by controlling the beam emittance through proper choice of the operating frequency, balancing of the forces acting on the beam, and realization in practical hardware. A most interesting aspect …
Date: January 1, 1990
Creator: Jameson, Robert A.
System: The UNT Digital Library
Performance enhancement program: Managers guide to marginal performance interventions (open access)

Performance enhancement program: Managers guide to marginal performance interventions

The marginal performer -- an employee who is not meeting performance standards established in the performance appraisal process -- is a fact of life that most supervisors eventually have to face. Screening of job applicants can reduce the number of employees with skill or performance difficulties, but problems can arise even with the most carefully chosen employee. They can also develop in people who were once productive.
Date: January 1, 1990
Creator: Bivins, C. S. & Phillips, R. R.
System: The UNT Digital Library
Treatment of low-activity-level process wastewaters by Continuous Countercurrent Ion Exchange (open access)

Treatment of low-activity-level process wastewaters by Continuous Countercurrent Ion Exchange

This paper discusses application of the Thomas model for predicting breakthrough curves from ion exchange column tests, methods for scale-up of experimental small-scaled ion exchange columns to industrial scale columns, and methods for predicting effluent compositions in a continuous countercurrent ion exchange system. 20 refs., 6 figs., 2 tabs.
Date: January 1, 1990
Creator: Hall, R.; Watson, J. S. & Robinson, S. M.
System: The UNT Digital Library
Analysis of nonlinear systems using ARMA (autoregressive moving average) models (open access)

Analysis of nonlinear systems using ARMA (autoregressive moving average) models

While many vibration systems exhibit primarily linear behavior, a significant percentage of the systems encountered in vibration and model testing are mildly to severely nonlinear. Analysis methods for such nonlinear systems are not yet well developed and the response of such systems is not accurately predicted by linear models. Nonlinear ARMA (autoregressive moving average) models are one method for the analysis and response prediction of nonlinear vibratory systems. In this paper we review the background of linear and nonlinear ARMA models, and illustrate the application of these models to nonlinear vibration systems. We conclude by summarizing the advantages and disadvantages of ARMA models and emphasizing prospects for future development. 14 refs., 11 figs.
Date: January 1, 1990
Creator: Hunter, N.F. Jr.
System: The UNT Digital Library
The puzzles of surface science and recent attempts to explain them (open access)

The puzzles of surface science and recent attempts to explain them

Surfaces have several unique properties that remain unexplained on the atomic level. These include (1) the unique chemical activity of rough surfaces, (2) the breaking of chemical bonds in narrow temperature ranges; and (3) the role of co-adsorption and strongly adsorbed monolayers during catalysis and tribological change (friction, lubrication). The dynamic surface restructuring model and surface structure induced variations in local density of states that have been suggested to rationalize the surface behavior await experimental confirmation. 24 refs., 10 figs., 2 tabs.
Date: July 1, 1990
Creator: Somorjai, G.A.
System: The UNT Digital Library
Modeling requirements for full-scope reactor simulators of fission-product transport during severe accidents (open access)

Modeling requirements for full-scope reactor simulators of fission-product transport during severe accidents

This paper describes in the needs and requirements to properly and efficiently model fission product transport on full scope reactor simulators. Current LWR simulators can be easily adapted to model severe accident phenomena and the transport of radionuclides. Once adapted these simulators can be used as a training tool during operator training exercises for training on severe accident guidelines, for training on containment venting procedures, or as training tool during site wide emergency training exercises.
Date: January 1, 1990
Creator: Ellison, P.G.; Monson, P.R. (Westinghouse Savannah River Co., Aiken, SC (United States)) & Mitchell, H.A. (Concord Associates, Inc., Knoxville, TN (United States))
System: The UNT Digital Library