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A parallel block cyclic reduction algorithm for the fast solution of elliptic equations (open access)

A parallel block cyclic reduction algorithm for the fast solution of elliptic equations

This paper presents an adaptation of the Block Cyclic Reduction (BCR) algorithm for a multi-vector processor. The main bottleneck of BCR lies in the solution of linear systems whose coefficient matrix is the product of tridiagonal matrices. This bottleneck is handled by expressing the rational function corresponding to the inverse of this product as a sum of elementary fractions. As a result the solution of this system leads to parallel solutions of tridiagonal systems. Numerical experiments performed on an Alliant FX/8 are reported. 11 refs., 1 tab.
Date: April 1, 1987
Creator: Gallopoulos, E. & Saad, Y.
System: The UNT Digital Library
High precision power supplies for the National Synchrotron Light Source (open access)

High precision power supplies for the National Synchrotron Light Source

Since beam stability depends to a considerable degree on the stability of the magnet power supplies, and it is desired to push for 3 GeV operation, it was required that new power supplies be obtained for the quadrupoles and sextupoles. These power supplies were to have the lowest ripple that could be reasonably achieved, and were to have a current regulation of better than 10 PPM. In addition, since they operate over a 5 : 1 voltage range, it was considered desirable to ensure that they operated with a good power factor over the operating range. The dipole power supply was modified to use the techniques employed in the smaller supplies.
Date: April 1, 1987
Creator: Olsen, R. & Langenbach, H.
System: The UNT Digital Library
The data acquisition system for SLD (open access)

The data acquisition system for SLD

This paper describes the data acquisition system planned for the SLD detector, which is being constructed for use with the SLAC Linear Collider (SLC). Analog electronics, heavily incorporating hybrid and custom VLSI circuitry, is mounted on the detector itself. Extensive use is made of multiplexing through optical fibers to a FASTBUS readout system. The low repetition rate of the SLC allows a relatively simple software-based trigger. Hardware and software processors within the acquisition modules are used to reduce the large volume of data per event and to calibrate the electronics. A farm of microprocessors is used for full reconstruction of a sample of events prior to transmission to the host.
Date: April 1, 1987
Creator: Sherden, D.J.
System: The UNT Digital Library
Nuclide migration from areal sources into a fracture (open access)

Nuclide migration from areal sources into a fracture

This document shows analytic solutions to the problem of hydrogeologic transport of radionuclides released from finite areal sources into a planar fracture. It illustrates the solutions through numerical and graphical displays of the spatial and temporal distribution of the radionuclides as a result of advection in the fracture, transverse dispersion and surface sorption, as well as diffusion into and sorption in the rock matrix. The numerical illustrations indicate that sufficient distances away from the sources equivalent single sources give acceptable approximations. 2 refs., 3 figs.
Date: April 1, 1987
Creator: Ahn, J.; Chambre, P. L.; Pigford, T. H. & Lee, W. W. L.
System: The UNT Digital Library
The decay tau. -->. rho nu (and rho. -->. pi. eta nu. ) (open access)

The decay tau. -->. rho nu (and rho. -->. pi. eta nu. )

Motivated by the question of missing exclusive branching fractions in tau decays, mostly suspected to be in one prong decays with neutrals, we have studied the decay tau ..-->.. rho nu in tau pair production by e/sup +/e/sup -/ annihilation at ..sqrt..s = 3.77 GeV. The branching fraction is measured to be B(tau ..-->.. rho nu) = (23.0 +- 1.3 +- 1.7)% consistent with known measurements and not offering a solution to the branching ratio question. No eta signal in the ..gamma gamma.. mass spectrum pointing to a decay tau ..-->.. eta ..pi.. nu is obvious. An upper limit on this branching fraction is given.
Date: April 1, 1987
Creator: Stockhausen, W.
System: The UNT Digital Library
Status of the SLC (SLAC Linear Collider) (open access)

Status of the SLC (SLAC Linear Collider)

A short review of the physics goals and the status of the SLC is followed by a discussion of the energy spectrometer with center-of-mass energy resolution on a pulse-to-pulse basis of +-50 MeV/c/sup 2/. The status of the SLC polarization experiment is discussed. The expected physics program of the Mark II is given.
Date: April 1, 1987
Creator: Moffeit, K.C.
System: The UNT Digital Library
The impact of new computer technology on accelerator control (open access)

The impact of new computer technology on accelerator control

This paper describes some recent developments in computing and stresses their application in accelerator control systems. Among the advances that promise to have a significant impact are (1) low cost scientific workstations; (2) the use of ''windows'', pointing devices and menus in a multi-tasking operating system; (3) high resolution large-screen graphics monitors; (4) new kinds of high bandwidth local area networks. The relevant features are related to a general accelerator control system. For example, this paper examines the implications of a computing environment which permits and encourages graphical manipulation of system components, rather than traditional access through the writing of programs or ''canned'' access via touch panels.
Date: April 1, 1987
Creator: Theil, E.; Jacobson, V. & Paxson, V.
System: The UNT Digital Library
Magnetic field dependence of the specific heat of some high-T/sub c/ (open access)

Magnetic field dependence of the specific heat of some high-T/sub c/

The specific heats, C, of 5 samples of La/sub 1.85/M/sub 0.15/CuO/sub 4-y/ (M = Ca, Sr, Ba), one sample of La/sub 2/CuO/sub 4-y/, and one sample of YBa/sub 2/Cu/sub 3/O/sub 9-y/ have been measured between 0.4 and 40K, in magnetic fields, H, to 7T. For the La/sub 1.85/M/sub 0.15/CuO/sub 4-y/ samples the H dependence of C near T/sub c/ and near 1K, where C is dominated by the electronic contribution, gives information about the fraction of the sample that is a bulk superconductor and the density of electronic states. The fraction of bulk superconductivity indicated by the Meissner effect does not correlate well with that indicated by C. La/sub 2/CuO/sub 4-y/ has a linear term in C, in qualitative agreement with a theoretical prediction.
Date: April 1, 1987
Creator: Phillips, N. E.; Fisher, R. A.; Lacy, S. E.; Marcenat, C.; Olsen, J. A.; Ham, W. K. et al.
System: The UNT Digital Library
Full length prototype SSC dipole test results (open access)

Full length prototype SSC dipole test results

Results are presented from tests of the first full length prototype SSC dipole magnet. The cryogenic behavior of the magnet during a slow cooldown to 4.5K and a slow warmup to room temperature has been measured. Magnetic field quality was measured at currents up to 2000 A. Averaged over the body field all harmonics with the exception of b/sub 2/ and b/sub 8/ are at or within the tolerances specified by the SSC Central Design Group. (The values of b/sub 2/ and b/sub 8/ result from known design and construction defects which will be be corrected in later magnets.) Using an NMR probe the average body field strength is measured to be 10.283 G/A with point to point variations on the order of one part in 1000. Data are presented on quench behavior of the magnet up to 3500 A (approximately 55% of full field) including longitudinal and transverse velocities for the first 250 msec of the quench.
Date: April 24, 1987
Creator: Strait, J.; Brown, B.C.; Carson, J.; Engler, N.; Fisk, H.E.; Hanft, R. et al.
System: The UNT Digital Library
The nature of beamstrahlung (open access)

The nature of beamstrahlung

The physical nature of beamstrahlung during beam-beam interaction in linear colliders is reviewed. We first make the distinction between a dense beam and a dilute beam. We then review the characteristics of synchrotron radiation (SR) and bremsstrahlung, and argue that for a wide range of beam parameters beamstrahlung is SR in nature, even if the beam is dilute. Some issues concerning the specific conditions in beamstrahlung as SR are then discussed. Finally we suggest that in order to suppress beamstrahlung energy loss and to improve energy resolution, it is desirable to partition a bunch into a train of bunchlets, where the length of each bunchlet is shorter than the SR convergence length.
Date: April 1, 1987
Creator: Chen, P.
System: The UNT Digital Library
Optical properties of tetravalent uranium in the solid state (open access)

Optical properties of tetravalent uranium in the solid state

The optical spectra are fit to the parameters of a phenomenological Hamiltonian from which a calculated spectrum is obtained. The goodness of fit is determined by the value of sigma (cm/sup -1/), the rms deviation. The sigma and crystal field are tabulated for U/sup 4 +/ in various host crystals, Pr/sup 3 +/ or Nd/sup 3 +/ in various crystals, and the free ion U/sup 4 +/. The rms deviation sigma for the U/sup 4 +/ compounds is much worse on the average than for the Pr/Nd examples. There appears to be a correlation between a poor fit and a large sigma, and a large crystal field. 28 refs., 1 tab. (DLC)
Date: April 1, 1987
Creator: Edelstein, N.
System: The UNT Digital Library
Mathematical models for predicting tritium transport in lithium ceramics (open access)

Mathematical models for predicting tritium transport in lithium ceramics

Tritium retention and release data for lithium ceramics (Li/sub 2/O, LiAlO/sub 2/, and Li/sub 4/SiO/sub 4/) are available from in-reactor and post-irradiation anneal tests on single crystals, powders, and sintered products. With the exception of the single-crystal tests in which bulk diffusion is the rate-limiting release mechanism, it is very difficult to interpret the results of these tests and extrapolate the results to design conditions for a fusion solid-breeder blanket. Mathematical models are presented for various bulk, grain-boundary, and free-surface phenomena to aid in the interpretation and extrapolation of the data. 24 refs., 6 figs., 4 tabs.
Date: April 1, 1987
Creator: Billone, M.C.
System: The UNT Digital Library
Tandem injected relativistic heavy ion facility at Brookhaven: Present and future (open access)

Tandem injected relativistic heavy ion facility at Brookhaven: Present and future

The Brookhaven Tandem Facility has been recently joined to the Alternating Gradient Synchrotron (AGS) by means of an approx. =680 meter long heavy ion transfer line. The design and construction of this line are described as well as the Tandem and AGS modifications which made it possible to initiate a relativistic heavy ion research program. Operational experience and performance during the first 14.6 GeV/amu /sup 16/O and /sup 28/Si runs are reviewed. At present the facility is capable of accelerating ions up to mass approx.32. Future developments are described which will lead to the acceleration of heavier ions up to gold, and hopefully to the construction of a relativistic heavy ion collider for the entire mass range at center of mass energies up to 250 GeV per nucleon pair.
Date: April 1, 1987
Creator: Thieberger, P.; Barton, D. S.; Benjamin, J.; Chasman, C.; Foelsche, H. & Wegner, H. E.
System: The UNT Digital Library
The Mark III vertex chamber: Studies using DME (open access)

The Mark III vertex chamber: Studies using DME

Studies have been performed using a prototype of a pressurized wire vertex chamber with 8 mm diameter straw geometry. A 35 ..mu..m spatial resolution using dimethyl ether (DME) at 1 bar and 30 ..mu..m using argon ethane (50/50 mixture) at 4 bar was obtained. Preliminary studies show the DME to adversely affect such materials as aluminized Mylar and Delrin.
Date: April 1, 1987
Creator: Pitman, D.
System: The UNT Digital Library
The evolution of HOBO (open access)

The evolution of HOBO

HOBO is a free-Lagrangian hydrodynamics code which has been under development at Los Alamos for several years. It was based on free-Lagrangian tracer points and finite difference approximations to the equations of motion for fluid flow. This method will be reviewed briefly here. The use of an independent time step at each point is also described. This technique increases the speed of the code by factors of 10 to 20. How the code has been modified to achieve energy and momentum conservation and how this effects the independent time step is also included, as well as the explicit tracking of material interfaces.
Date: April 1, 1987
Creator: Clark, R. A.
System: The UNT Digital Library
Review of the abort dump shown in the SSC (superconducting super collider) conceptual design report (open access)

Review of the abort dump shown in the SSC (superconducting super collider) conceptual design report

This report details the design of the abort dump for the Superconducting Super-Collider (SSC). The dump is made from graphite and designed to absorb the maximum beam energy of 400 MJ. The report considers long time activation effects of the dump components. The report concludes that the basic design of the abort dump is well defined. (JDH)
Date: April 1, 1987
Creator: Cossairt, J.D.
System: The UNT Digital Library
An upper limit on the decay D/sup 0/. -->. mu. e (open access)

An upper limit on the decay D/sup 0/. -->. mu. e

A search for the lepton family number violating decay D/sup 0/ ..-->.. ..mu..e is reported. No signal is observed in a data sample of 9.3 pb/sup -1/ collected at the psi(3770) resonance with the Mark III detector, where 0.18 +- 0.06 +- 0.05 background events are expected. A 90% confidence level upper limit on the branching fraction B(D/sup 0/ ..-->.. ..mu..e) of 1.5 x 10/sup -4/ is obtained.
Date: April 1, 1987
Creator: Stockhausen, W.
System: The UNT Digital Library
Status of inertial fusion (open access)

Status of inertial fusion

The technology advancement to high-power beams has also given birth to new technologies. That class of Free Electron Lasers that employs rf linacs, synchrotrons, and storage rings - although the use the tools of High Energy Physics (HEP) - was developed well behind the kinetic energy frontier. The induction linac, however, is something of an exception; it was born directly from the needs of the magnetic fusion program, and was not motivated by a high-energy physics application. The heavy-ion approach to inertial fusion starts with picking from the rich menu of accelerator technologies those that have, ab initio, the essential ingredients needed for a power plant driver: multigap acceleration - which leads to reliability/lifetime; electrical efficiency; repetition rate; and beams that can be reliably focused over a suitably long distance. The report describes the programs underway in Heavy Ion Fusion Accelerator Research as well as listing expected advances in driver, target, and beam quality areas in the inertial fusion power program.
Date: April 1, 1987
Creator: Keefe, D.
System: The UNT Digital Library
Present and future prospects of accelerator mass spectrometry (open access)

Present and future prospects of accelerator mass spectrometry

Accelerator Mass Spectrometry (AMS) has become a powerful technique for measuring extremely low abundances (10/sup -10/ to 10/sup -15/ relative to stable isotopes) of long-lived radioisotopes with half-lives in the range from 10/sup 2/ to 10/sup 8/ years. With a few exceptions, tandem accelerators turned out to be the most useful instruments for AMS measurements. Both natural (mostly cosmogenic) and man-made (anthropogenic) radioisotopes are studied with this technique. In some cases very low concentrations of stable isotope are also measured. Applications of AMS cover a large variety of fields including anthropology, archaeology, oceanography, hydrology, climatology, volcanology, minerals exploration, cosmochemistry, meteoritics, glaciology, sedimentary processes, geochronology, environmental physics, astrophysics, nuclear and particle physics. Present and future prospects of AMS are discussed as an interplay between the continuous development of new techniques and the investigation of problems in the above mentioned fields. Typical factors to be considered are energy range and type of accelerator, and the possibilities of dedicated versus partial use of new or existing accelerators.
Date: April 1, 1987
Creator: Kutschera, W.
System: The UNT Digital Library
The interdependence of parameters for TeV linear colliders (open access)

The interdependence of parameters for TeV linear colliders

A call, at SLAC, for a design of a 0.5 + 0.5 TeV e/sup +/e/sup -/ collider with a luminosity of at least 10/sup 33/ cm/sup -2/ sec/sup -1/ has been made. In order to find whether such a machine is possible, approximate formulae are collected for many of the relations governing the design of a linear collider. It must be emphasized that these are often only approximate relations whose accuracy is not expected to be better than about 10%, and in some cases may be worse. Units throughout will be meter-kilogram-second (mks) unless otherwise stated. Given these relations, their interdependence is studied and parameter choices made. A self-consistent solution is found that meets specification and does not involve any exotic technologies.
Date: April 1, 1987
Creator: Palmer, Robert B.
System: The UNT Digital Library
Comparison of electric and magnetic quadrupole focusing for the low energy end of an induction-linac-ICF (Inertial-Confinement-Fusion) driver (open access)

Comparison of electric and magnetic quadrupole focusing for the low energy end of an induction-linac-ICF (Inertial-Confinement-Fusion) driver

This report compares two physics designs of the low energy end of an induction linac-ICF driver: one using electric quadrupole focusing of many parallel beams followed by transverse combining; the other using magnetic quadrupole focusing of fewer beams without beam combining. Because of larger head-to-tail velocity spread and a consequent rapid current amplification in a magnetic focusing channel, the overall accelerator size of the design using magnetic focusing is comparable to that using electric focusing.
Date: April 1, 1987
Creator: Kim, C.H.
System: The UNT Digital Library
The Mobile Intercontinental Ballistic Missile (MICBM) simulation (open access)

The Mobile Intercontinental Ballistic Missile (MICBM) simulation

The purpose of this project was to investigate the capability of blending traditional discrete event simulation techniques with artificial intelligence technology. In order to fully demonstrate the capabilities of such a simulation environment, a difficult class of simulation problem was selected for the project: a military C/sup 3/ (command, control, and communication) simulation. The hardware chosen for the project was a Symbolics LISP machine running an artificial intelligence shell called Knowledge Engineering Environment (KEE). This environment provided a powerful simulation capability in which human decision-making processes could be readily represented.
Date: April 6, 1987
Creator: Roberts, D. J.; Morgeson, J. D.; Dreicer, J. & Egdorf, H. W.
System: The UNT Digital Library
Turbulence (open access)

Turbulence

Current theories for material mixing include multiphase interpenetration and single-field turbulence transport with large density variations. Neither approach by itself is adequate for current problem-solving needs, but in combination they offer tremendous opportunities for the analysis of complex material dynamics. Multiphase theory contributes the ''ordered'' jets or particulate trajectories that penetrate in wave-like fashion; turbulence transport superimposes the important nonlinear diffusive component to the mixing. Shear impedance and energy transport arise naturally in this combined analysis.
Date: April 1, 1987
Creator: Harlow, F. H.
System: The UNT Digital Library
Martin Marietta Energy Systems Nuclear Criticality Safety Improvement Program (open access)

Martin Marietta Energy Systems Nuclear Criticality Safety Improvement Program

This report addresses questions raised by criticality safety violation at several DOE plants. Two charts are included that define the severity and reporting requirements for the six levels of accidents. A summary is given of all reported criticality incident at the DOE plants involved. The report concludes with Martin Marietta's Nuclear Criticality Safety Policy Statement. (JDH)
Date: April 29, 1987
Creator: Speas, I.G.
System: The UNT Digital Library