59 Matching Results

Results open in a new window/tab.

Comparing the Floating Point Systems, Inc. AP-190L to representative scientific computers: some benchmark results (open access)

Comparing the Floating Point Systems, Inc. AP-190L to representative scientific computers: some benchmark results

Results are presented of comparative timing tests made by running a typical FORTRAN physics simulation code on the following machines: DEC PDP-10 with KI processor; DEC PDP-10, KI processor, and FPS AP-190L; CDC 7600; and CRAY-1. Factors such as DMA overhead, code size for the AP-190L, and the relative utilization of floating point functional units for the different machines are discussed. 1 table.
Date: March 27, 1980
Creator: Brengle, T.A. & Maron, N.
System: The UNT Digital Library
Magnetic shielding design analysis (open access)

Magnetic shielding design analysis

Two passive magnetic-shielding-design approaches for static external fields are reviewed. The first approach uses the shielding solutions for spheres and cylinders while the second approach requires solving Maxwell's equations. Experimental data taken at LLNL are compared with the results from these shieldings-design methods, and improvements are recommended for the second method. Design considerations are discussed here along with the importance of material gaps in the shield.
Date: December 27, 1983
Creator: Kerns, J.A.; LaPaz, A.D. & Fabyan, J.
System: The UNT Digital Library
The excess flux in the cosmic submillimeter background radiation and the primordial deuterium abundance (open access)

The excess flux in the cosmic submillimeter background radiation and the primordial deuterium abundance

Recent measurements of the cosmic background radiation (CBR) show an enhanced flux in the submillimeter regime, compared to the spectrum of a 2.7 K blackbody. Thermal Comptonization of the relic radiation by a hot nonrelativistic plasma has long been known to produce distortions in the CBR spectrum, similar to what has now been observed. Heating of the primeval plasma to temperatures T {approximately} 10{sup 6} {minus} 10{sup 8} K could result from the injection of subcosmic ray protons at epoch z {approximately} 10--100. The intensity of the subcosmic ray flux that provide conditions needed to explain the submillimeter excess by thermal Comptonization also leads to the production of cosmologically significant amounts of deuterium in collisions between subcosmic ray protons and primordial protons and {alpha}-particles. However, the amount of lithium produced through {alpha}-{alpha} reactions is in conflict with the observed Li abundance. If lithium is depleted, for example, by processing through Population II stars, arguments for the baryon content of the universe based on primordial deuterium and He abundances are weakened. 12 refs., 1 fig., 1 tab.
Date: October 27, 1989
Creator: Dermer, C. D.; Guessoum, N. (Lawrence Livermore National Lab., CA (USA) & National Aeronautics and Space Administration, Greenbelt, MD (USA). Lab. for High Energy Astrophysics)
System: The UNT Digital Library
Seismic review of the R. E. Ginna Nuclear Power Plant as part of the Systematic Evaluation Program for the Nuclear Regulatory Commission (open access)

Seismic review of the R. E. Ginna Nuclear Power Plant as part of the Systematic Evaluation Program for the Nuclear Regulatory Commission

This paper is a progress report on work at the Lawrence Livermore National Laboratory (LLNL) to perform a limited seismic reassessment of the Robert E. Ginna Nuclear Power Plant. The reassessment is being done for the Nuclear Regulatory Commission (NRC) as part of the Systematic Evaluation Program. The reassessment focuses generally on the reactor coolant pressure boundary and on those systems and components necessary to shut down the reactor safely and to maintain it in a safe shutdown condition following a postulated earthquake characterized by a peak horizontal ground acceleration of 0.2 g. Methods and modeling procedures used to analyze a complex of interconnected buildings are highlighted.
Date: May 27, 1980
Creator: Murray, R. C.; Nelson, T. A.; Ng, D. S.; Liaw, C. Y.; Levin, H. A. & Cheng, T. M.
System: The UNT Digital Library
MTX/ELF II (Microwave Tokamak Experiment/ Electron Laser Facility II) microwave power measurements and calibration for the 2-GW, 140-GHZ, ELF II free-electron laser (FEL) (open access)

MTX/ELF II (Microwave Tokamak Experiment/ Electron Laser Facility II) microwave power measurements and calibration for the 2-GW, 140-GHZ, ELF II free-electron laser (FEL)

We have developed techniques for measuring the power and frequency of the Electron Laser Facility (ELF) II free-electron laser (FEL) used for plasma heating experiments on the Microwave Tokamak Experiment (MTX). We also have designed a multichannel, 140-GHz receiver capable of measuring FEL power levels from 10 mW to 0.1 {mu}W within an accuracy of {plus minus}1 dB with a 50-dB dynamic range and a 2-ns response time. By using calibrated attenuators, we can measure power levels from 10 GW to 0.1 {mu}W. We sample the microwave output of the FEL in a microwave load tank by using WR-8 or WR-28 stub waveguide antennas. Microwave turning mirrors are used to guide the microwave beam down an evacuated beam tube to the MTX. Stub, WR-8, fundamental-mode, waveguide antennas are used for beam detection on the microwave turning mirrors. Orthogonal, WR-8, stub waveguides are machined into the surfaces of the mirrors and used as directional couplers to measure forward and reflected power from the FEL. The microwave power is then transported to the microwave receiver via a low-loss, over-moded, WR-28 waveguide. A movable modes probe in the microwave load tank is used to scan across the microwave beam to determine the modes …
Date: September 27, 1989
Creator: Ferguson, S.W.; Stever, R.; Throop, A.; Felker, B. & Franklin, R.
System: The UNT Digital Library
Laser-fusion rocket for interplanetary propulsion (open access)

Laser-fusion rocket for interplanetary propulsion

A rocket powered by fusion microexplosions is well suited for quick interplanetary travel. Fusion pellets are sequentially injected into a magnetic thrust chamber. There, focused energy from a fusion Driver is used to implode and ignite them. Upon exploding, the plasma debris expands into the surrounding magnetic field and is redirected by it, producing thrust. This paper discusses the desired features and operation of the fusion pellet, its Driver, and magnetic thrust chamber. A rocket design is presented which uses slightly tritium-enriched deuterium as the fusion fuel, a high temperature KrF laser as the Driver, and a thrust chamber consisting of a single superconducting current loop protected from the pellet by a radiation shield. This rocket can be operated with a power-to-mass ratio of 110 W gm/sup -1/, which permits missions ranging from occasional 9 day VIP service to Mars, to routine 1 year, 1500 ton, Plutonian cargo runs.
Date: September 27, 1983
Creator: Hyde, R.A.
System: The UNT Digital Library
Use of the Egret instrument in studies of the origin of the cosmic radiation (open access)

Use of the Egret instrument in studies of the origin of the cosmic radiation

This is a continuation of previous studies aimed at predicting spectral signatures of discrete cosmic-ray sources. In this paper, a formalism is developed for calculating gamma-ray spectra observed at Earth from the decay of neutral pions formed in collisions of cosmic-ray protons and ions with galactic gas and dust. The cosmic rays are assumed to be emitted by discrete sources, and their intensities and spectra are described by solutions to a diffusion equation. Calculations of spectral signatures expected from these hypothetical point sources of cosmic rays are presented. In particular, a steady source of cosmic rays could show a harder gamma-ray spectrum than the spectrum of the diffuse galactic background, whereas an impulsive source of cosmic rays could show a much softer spectrum. Observations of the angular variations of gamma-ray intensities and spectra near point sources will provide information on cosmic-ray propagation in other parts of our galaxy, as well as on the nature of the discrete sources themselves. Capabilities of the Egret telescope in mapping spectra from cosmic-ray point sources are briefly discussed. 14 refs., 2 figs.
Date: October 27, 1989
Creator: Dermer, C. D.
System: The UNT Digital Library
Transients - abnormal and otherwise (open access)

Transients - abnormal and otherwise

Information is presented concerning transients in research reactors and nuclear power plants.
Date: September 27, 1983
Creator: Hendrie, J. M.
System: The UNT Digital Library
Microwave transport system for the MTX (Microwave Tokamak Experiment) (open access)

Microwave transport system for the MTX (Microwave Tokamak Experiment)

This paper presents the design and construction, as well as the initial operation, of the Microwave Transmission System. The system consists of containment vessels, mirror boxes, mirrors, an alignment system, two turbo-molecular pump vacuum stations, and microwave source. Fifty-ns-length pulses of 6-MeV electrons pass through a free electron laser (FEL) wiggler. A 300 W extended interaction oscillator (EIO) of 140 GHz frequency supplies the seed signal for amplification in the wiggler. The electron beam is dumped and the microwave beam is transmitted quasi-optically 90 ft by six aluminum mirrors through an evacuated tube. Three of the mirrors are elliptical paraboloids and the others are flat. A seventh mirror is rotated into the microwave beam to divert it into a load tank. The transport vacuum vessel is 20-in.-diameter stainless steel tube with bellows and mirror boxes at each mirror. Two vacuum systems at each end of the transport tube allow a base pressure of 10{sup {minus}7} Torr to be attained by 7000 L/s of turbo-molecular pumping. Also at each mirror, at the MTX vessel, and at the two ends of the wiggler waveguide are HeNe laser detectors used for vacuum alignment. Descriptions of the major components, their requirements and system requirements …
Date: September 27, 1989
Creator: Felker, B. & Ferguson, S.W.
System: The UNT Digital Library
Longitudinal compression of heavy-ion beams with minimum requirements on final focus (open access)

Longitudinal compression of heavy-ion beams with minimum requirements on final focus

A method is developed to compress a heavy-ion beam longitudinally in such a way that the compressed pulse has a constant line-charge density profile and uniform longitudinal momentum. These conditions may be important from the standpoint of final focusing. By realizing the similarity of the equations that describe the 1-D charged-particle motion to the equations that describe 1-D ideal gas flow, the evolution of lambda and the velocity tilt can be calculated using the method of characteristics developed for unsteady supersonic gasdynamics. Particle simulations confirm the theory. Various schemes for pulse shaping have been investigated.
Date: May 27, 1986
Creator: Ho, D.D.M.; Bangerter, R.O.; Mark, J.W.K.; Brandon, S.T. & Lee, E.P.
System: The UNT Digital Library
Understanding Modern Magnets through Conformal Mapping (open access)

Understanding Modern Magnets through Conformal Mapping

When I had to choose, within some narrow range, the topic of this paper, I received great help from a colleague in Berkeley and from Prof. Little when it was suggested that I should pick among the possible subjects of my talk the subject that Prof. Bloch would have enjoyed most. Since Prof. Bloch would prefer a scalpel over a sword every time, I hope and think that most people will approve my choice. When one intends to talk about a subject that is as old as conformal mapping and one does not want to lose the audience in a very short time, it is advisable to start by explaining both the motivation for the talk as well as the goals one has in mind when giving the talk. This particular talk has been motivated by the increasing frequency with which one hears, from people that ought to know better, statements like: 'Conformal mapping is really a thing of the past because of all the marvelous computer programs that we now have'. Even though, or more likely because, I have been intimately involved in the development of some large and widely used computer codes, I am deeply disturbed by such …
Date: October 27, 1989
Creator: Halbach, K.
System: The UNT Digital Library
Damping beam displacements through phase mixing: an illustrative model (open access)

Damping beam displacements through phase mixing: an illustrative model

We develop a simple model of a beam transported in a hard wall channel (an idealized very-high-order magnetic-multipole channel). The extremely anharmonic nature of the potential leads to damping of coherent transverse displacements of the beam via phase mixing. For the case of small uniform displacements of the beam we can write down by inspection the analytical form of the motion of the beam centroid. The same technique allows us to evaluate the effects of focussing and scattering elements in the transport channel upon the damping of the transverse motion of the beam.
Date: May 27, 1983
Creator: Barletta, W. A. & Briggs, R. J.
System: The UNT Digital Library
Use of the ORACLE DBMS in determining the response of complex scientific instrumentation (open access)

Use of the ORACLE DBMS in determining the response of complex scientific instrumentation

In the Laser Fusion Program at Lawrence Livermore National Laboratory, a single laser fusion experiment lasts only a billionth of a second but in this time high speed instrumentation collects data that when digitized will create a data bank of several megabytes. This first level of data must be processed in several stages to put it in a form useful for interpretation of the experiments. One stage involves unfolding the source characteristics from the data and response of the instrument. This involves calculating the response of the instrument from the characteristics of each of its components. It is in this calculation that the ORACLE DBMS has become an invaluable tool for manipulation and archiving of the component data.
Date: June 27, 1984
Creator: Auerbach, J.M.; DeMartini, B.J. & McCauley, E.W.
System: The UNT Digital Library
Waste classification - history, standards, and requirements for disposal (open access)

Waste classification - history, standards, and requirements for disposal

This document contains an outline of a presentation on the historical development in US of different classes (categories) or radioactive waste, on laws and regulations in US regarding classification of radioactive wastes; and requirements for disposal of different waste classes; and on the application of laws and regulations for hazardous chemical wastes to classification and disposal of naturally occurring and accelerator-produced radioactive materials; and mixed radioactive and hazardous chemical wastes.
Date: June 27, 1989
Creator: Kocher, David C.
System: The UNT Digital Library
All-optical modulation in gallium arsenide integrated optical waveguides (open access)

All-optical modulation in gallium arsenide integrated optical waveguides

We have investigated all-optical modulators in gallium arsenide integrated optical waveguides; these modulators use electron-hole pair generation to alter the propagation characteristics of a guided light beam. 6 refs., 6 figs.
Date: January 27, 1988
Creator: McWright, G.; Ross, B.; Guthreau, W.; Lafaw, D.; Lowry, M. & Tindall, W.
System: The UNT Digital Library
Twos in two photon physics: A convention for the. gamma. gamma. * width of a spin-one particle (open access)

Twos in two photon physics: A convention for the. gamma. gamma. * width of a spin-one particle

The two conventions for the {gamma}{gamma}* width of a spin-one resonance are discussed. It is shown that the more reasonable one is the one that gives the larger experimental value. 5 refs.
Date: May 27, 1988
Creator: Cahn, R.N.
System: The UNT Digital Library
Cytometric analysis of mammalian sperm for induced morphologic and DNA content errors (open access)

Cytometric analysis of mammalian sperm for induced morphologic and DNA content errors

Some flow-cytometric and image analysis procedures under development for quantitative analysis of sperm morphology are reviewed. The results of flow-cytometric DNA-content measurements on sperm from radiation exposed mice are also summarized, the results related to the available cytological information, and their potential dosimetric sensitivity discussed. (ACR)
Date: June 27, 1983
Creator: Pinkel, D.
System: The UNT Digital Library
Physics of the synchrotron model of cosmic gamma-ray bursts (open access)

Physics of the synchrotron model of cosmic gamma-ray bursts

We review the theoretical arguments leading to the thermal synchrotron model of cosmic gamma-ray bursts. We propose a magnetic flare-resonant absorption mechanism for the production of the hot electrons that can account for most of the unusual properties of the emission layer.
Date: September 27, 1983
Creator: Liang, E.P.
System: The UNT Digital Library
Proposal for a new tomographic device providing information on the chemical properties of a body section (open access)

Proposal for a new tomographic device providing information on the chemical properties of a body section

A system to analyze the chemical properties of a region of tissue located deep inside the human body without having to access it is proposed. The method is based on a high precision detection of x-rays or ..gamma..-rays (photons) from an external source Compton scattered from the tissue under inspection. The method provides chemical information of plane regions lying not too deep inside the body (<6 cm). The amount of radiation absorbed by the body is about the same as needed for a standard x-ray tomography. The exposure time is estimated to be shorter than 10 minutes. 37 refs., 13 figs.
Date: February 27, 1986
Creator: Gatti, E.; Rehak, P. & Kemmer, J.
System: The UNT Digital Library
Neutrino electron scattering at LAMPF (open access)

Neutrino electron scattering at LAMPF

The limits of applicability of the standard model are considered. The theory is described from an experimenter's viewpoint, emphasizing the observables. The present experimental situation is summarized. The aspects of symmetry breaking, radiative corrections, scattering of neutrinos from hadrons, and neutrino-electron scattering are discussed. The discussion is meant to underscore the need for a really precise measurement of the Weinberg angle in the scattering mode. A proposed LAMPF experiment is then described which is meant to combine excellent statistical precision with the potential for low systematic uncertainty in order to make such a measurement. (LEW)
Date: November 27, 1985
Creator: White, D. Hywel
System: The UNT Digital Library
The role of the axial anomaly in determining spin-dependent parton distributions (open access)

The role of the axial anomaly in determining spin-dependent parton distributions

It is shown that the forward matrix elements of j{sub 5}{sup {mu}}, the flavor singlet axial vector current, do not measure the helicity carried by quarks and anti-quarks but also include a spin-dependent gluonic component due to the anomaly. Detailed phenomenological and field theoretic reasons are given for the necessity of a gluonic component in the matrix element of j{sub 5}{sup {mu}}. The first higher order corrections to the basic box and triangle graphs are discussed and shown not to modify the conclusions drawn in the leading order calculation. We close with a few comments on the possible phenomenological implications of the anomalous contribution. 25 refs., 6 figs.
Date: July 27, 1989
Creator: Carlitz, R.D.; Collins, J.C. & Mueller, A.H.
System: The UNT Digital Library
Sodium technology activities at HEDL in support of fast reactor development and the FFTF (open access)

Sodium technology activities at HEDL in support of fast reactor development and the FFTF

Activities of the Hanford Engineering Development Laboratory are presented. A brief description of FFTF and some highlights of reactor operations are reviewed. The sodium technology work at HEDL is summarized by discussing several facets of the program and their tie-ins to breeder reactor development.
Date: February 27, 1984
Creator: Atwood, J.M.
System: The UNT Digital Library
Aerosol deposition and losses in two alpha air monitors (open access)

Aerosol deposition and losses in two alpha air monitors

We assessed particle deposition and loss occurring in two alpha-air monitors: an Eberline Alpha-3 Continuous Air Monitor (CAM) and a working-area transuranic aerosol monitor (WOTAMS). We investigated the dependence of particle size on losses in the sampling inlets and the real-time alpha detector areas for both instruments. We determined the uniformity of particle deposition on the filter to ascertain the effectiveness of the detector and collection-filter configuration. Results indicate that particle losses are a strong function of particle size in the CAM unit, with a 44% loss occurring for 6-..mu..m-diameter aerosols and a 0.3% loss for 0.6-..mu..m-diameter aerosols. Losses in the WOTAMS were less than 1% for particle diameters in the 0.6-to-7 ..mu..m range.
Date: November 27, 1985
Creator: Biermann, A.H. & Sawyer, S.R.
System: The UNT Digital Library
Improved 50-kV pulser design (open access)

Improved 50-kV pulser design

A compact 50 kilovolt pulser has been developed as a gas switch trigger. This unit combines a grounded grid thyratron with a ferrite loaded step-up transformer to provide the required output voltage. A magnetic switch at the output brings the risetime down to the ten nanosecond range. Unit operation is specified into a 25 ohm resistive load. Integral with the pulser package is the necessary low level support electronics to power the thyratron and to provide trigger and diagnostic functions. Package volume is less than .02 m/sup 3/.
Date: May 27, 1982
Creator: Oicles, J.A. & Fulkerson, E.S.
System: The UNT Digital Library