Quark deconfinement and high energy nuclear collisions (open access)

Quark deconfinement and high energy nuclear collisions

Statistical QCD predicts that with increasing density, strongly interacting matter will undergo a transition to a plasma of deconfined quarks and gluons. High energy heavy ion collisions are expected to permit experimental studies of this transition and of the predicted new state of matter. 22 refs., 6 figs.
Date: July 1, 1986
Creator: Satz, H.
Object Type: Article
System: The UNT Digital Library
Stock Assessment of Columbia River Anadromous Salmonids: Final Report, Volume 1. Chinook, Coho, Chum and Sockeye Salmon Summaries. (open access)

Stock Assessment of Columbia River Anadromous Salmonids: Final Report, Volume 1. Chinook, Coho, Chum and Sockeye Salmon Summaries.

The purpose was to identify and characterize the wild and hatchery stocks of salmon and steelhead in the Columbia River Basin on the basis of currently available information. This report provides a comprehensive compilation of data on the status and life histories of Columbia Basin salmonid stocks.
Date: July 1, 1986
Creator: Howell, Philip J.
Object Type: Report
System: The UNT Digital Library
Steady-state and transient radionuclide transport through penetrations in nuclear waste containers (open access)

Steady-state and transient radionuclide transport through penetrations in nuclear waste containers

The transport of radionuclides through penetrations in wastes containers is analyzed. Penetrations may result from corrosion or cracks and may occur in the original container material, in degraded or corroded material, or in deposits of corrosion products. In this report we do not consider how these penetrations occur or the characteristics of expected penetrations in waste containers. We are concerned here only with the analytical formulation and solutions of equations to predict rates of mass transfer through penetrations of specified size and geometry. Expressions for the diffusive mass transfer rates through apertures are presented in Chapter 2, and numerical illustrations are presented in Chapter 3. The calculations show that mass transfer through small penetrations in thin-wall containers can be great enough that the penetrated container is no longer an effective barrier for radionuclide release. Use of this theory to calculate mass transfer through thick-wall containers is the subject of a later report. 3 refs., 9 figs.
Date: July 1, 1986
Creator: Chambre, P. L.; Lee, W. W. L.; Kim, C. L. & Pigford, T. H.
Object Type: Report
System: The UNT Digital Library
Linear accelerators of the future (open access)

Linear accelerators of the future

Some of the requirements imposed on future linear accelerators to be used in electron-positron colliders are reviewed, as well as some approaches presently being examined for meeting those requirements. RF sources for use in these linacs are described, as well as wakefields, single bunches, and multiple-bunch trains. (LEW)
Date: July 1, 1986
Creator: Loew, G.A.
Object Type: Article
System: The UNT Digital Library
Highlights of the heavy ion fusion symposium (open access)

Highlights of the heavy ion fusion symposium

The current status and prospects for inertial confinement fusion based on the use of intense beams of heavy ions will be described in the light of results presented at the International Symposium on Heavy Ion Fusion, (Washington, DC, May 27-29, 1986).
Date: July 1, 1986
Creator: Keefe, D.
Object Type: Article
System: The UNT Digital Library
Charge-exchange measurements of MHD activity during neutral beam injection in the Princeton Large Torus and the Poloidal Divertor Experiment (open access)

Charge-exchange measurements of MHD activity during neutral beam injection in the Princeton Large Torus and the Poloidal Divertor Experiment

The horizontally scanning, multiangle charge-exchange analyzers on the Princeton Large Torus (PLT) and the Poloidal Divertor Experiment (PDX) were used to study the effects of MHD activity on the background ion distribution function and on the beam ion slowing-down process during high-power neutral injection. Sawtooth oscillations were observed in the fast ion flux on PLT and PDX, and measurements with neutral beams providing local neutral density enhancement indicate that ions are transported radially when these events occur. With near-perpendicular injection in PDX, at the lower toroidal fields necessary to maximize beta, rapid, repetitive bursts of greatly enhanced charge-exchange flux were observed. These are associated with the ''fishbone'' MHD instability, and a substantial depletion of the perpendicular slowing-down spectrum below the injection energy was seen. A simple phenomenological model for this loss mechanism was developed, and its use in simulation codes has been successful in providing good agreement with the data. The behavior and characteristics of this model are well matched by the direct theoretical calculations.
Date: July 1, 1986
Creator: Goldston, R. J.; Kaita, R.; Beiersdorfer, P.; Gammel, G.; Herndon, D. L.; McCune, D. C. et al.
Object Type: Report
System: The UNT Digital Library
Nonlinear evolution of drift instabilities in the presence of collisions (open access)

Nonlinear evolution of drift instabilities in the presence of collisions

Nonlinear evolution of drift instabilities in the presence of electron-ion collisions in a shear-free slab has been studied by using gyrokinetic particle simulation techniques as well as by solving, both numerically and analytically, model mode-coupling equations. The purpose of the investigation is to determine the mechanisms responsible for the nonlinear saturation of the instability and for the ensuing steady-state transport. Such an insight is very valuable for understanding drift wave problems in more complicated geometries. The results indicate that the electron E x B convection is the dominant mechanism for saturation. It is also found that the saturation amplitude and the associated quasilinear diffusion are greatly enhanced over their collisionless values as a result of weak collisions. In the highly collisional (fluid) limit, there is an upper bound for saturation with ephi/T/sub e/ approx. = (..omega../sub l//..cap omega../sub i/)/(k/sub perpendicular/rho/sub s/)/sup 2/. The associated quasilinear diffusion, which increases with collisionality, takes the form of D/sub ql/ approx. = ..gamma../sub l//k/sub perpendicular//sup 2/, where ..omega../sub l/ and ..gamma../sub l/ are the linear frequency and growth rate, respectively. In the steady state, the diffusion process becomes stochastic in nature. The relevant mechanisms here are related to the velocity-space nonlinearities and background fluctuations. …
Date: July 1, 1986
Creator: Federici, J. F.; Lee, W. W. & Tang, W. M.
Object Type: Report
System: The UNT Digital Library
Fragmentation model applied to exclusive final states in photon-photon collisions (open access)

Fragmentation model applied to exclusive final states in photon-photon collisions

Monte Carlo calculations with the Lund string fragmentation model are compared to experimental results on the reactions ..gamma gamma -->..2..pi../sup +/2..pi../sup -/, ..gamma gamma -->..K/sup +/K/sup -/..pi../sup +/..pi../sup -/ and ..gamma gamma -->..p anti p..pi../sup +/..pi../sup -/. It is found, that when the parameters of the Lund model are tuned to low energy, inclusive multi hadron production in photon-photon collisions, the cross sections of exclusive processes near threshold are qualitatively reproduced. 14 refs., 3 figs.
Date: July 1, 1986
Creator: Buijs, A.
Object Type: Article
System: The UNT Digital Library
Coupled-channel analysis of neutron scattering from /sup 12/C between 9 and 15 MeV (open access)

Coupled-channel analysis of neutron scattering from /sup 12/C between 9 and 15 MeV

A deformed and energy dependent phenomenological optical model potential and coupled-channel formalism for deformed nuclei have been used in the analysis of elastic and inelastic (Q = 4.439 MeV) scattering, and analyzing power for neutrons scattered from /sup 12/C in the energy range of 9 to 15 MeV. 6 refs., 1 fig., 1 tab.
Date: July 1, 1986
Creator: Hansen, L. F. & Meigooni, A. S.
Object Type: Article
System: The UNT Digital Library
Front-end data processing the SLD data acquisition system (open access)

Front-end data processing the SLD data acquisition system

The data acquisition system for the SLD detector will make extensive use of parallel at the front-end level. Fastbus acquisition modules are being built with powerful processing capabilities for calibration, data reduction and further pre-processing of the large amount of analog data handled by each module. This paper describes the read-out electronics chain and data pre-processing system adapted for most of the detector channels, exemplified by the central drift chamber waveform digitization and processing system.
Date: July 1, 1986
Creator: Nielsen, B. S.
Object Type: Article
System: The UNT Digital Library
Review and problem definition of water/rock reactions associated with injection of spent geothermal fluids from a geothermal plant into aquifers (open access)

Review and problem definition of water/rock reactions associated with injection of spent geothermal fluids from a geothermal plant into aquifers

Among the technical problems faced by the burgeoning geothermal industry is the disposal of spent fluids from power plants. Except in unusual circumstances the normal practice, especially in the USA, is to pump these spent fluids into injection wells to prevent contamination of surface waters, and possibly in some cases, to reduce pressure drawdown in the producing aquifers. This report is a survey of experience in geothermal injection, emphasizing geochemical problems, and a discussion of approaches to their possible mitigation. The extraction of enthalpy from geothermal fluid in power plants may cause solutions to be strongly supersaturated in various dissolved components such as silica, carbonates, sulfates, and sulfides. Injection of such supersaturated solutions into disposal wells has the potential to cause scaling in the well bores and plugging of the aquifers, leading to loss of injectivity. Various aspects of the geochemistry of geothermal brines and their potential for mineral formation are discussed, drawing upon a literature survey. Experience of brine treatment and handling, and the economics of mineral extraction are also addressed in this report. Finally suggestions are made on future needs for possible experimental, field and theoretical studies to avoid or control mineral scaling.
Date: July 1, 1986
Creator: Elders, W. A.
Object Type: Report
System: The UNT Digital Library
MEVVA ion source for high current metal ion implantation (open access)

MEVVA ion source for high current metal ion implantation

The MEVVA (Metal Vapor Vacuum Arc) ion source is a new kind of source which can produce high current beams of metal ions. Beams of a wide range of elements have been produced, spanning the periodic table from lithium up to and including uranium. The source extraction voltage is up to 60 kV, and we are increasing this up to 120 kV. A total ion beam current of over 1 Ampere has been extracted from the present embodiment of the concept, and this is not an inherent limit. The ion charge state distribution varies with cathode material and arc current, and beams like Li/sup +/, Co/sup +,2+,3+/ and U/sup 3+,4+,5+,6+/ for example, are typical; thus the implantation energy can be up to several hundred kilovolts without additional acceleration. The ion source has potential applications for ion implantation and ion beam mixing for achievement of improved corrosion resistance or wear resistance in metals or surface modification of ceramic materials and semiconductors. Here we outline the source and its performance, and describe some very preliminary implantation work using this source.
Date: July 1, 1986
Creator: Brown, I. & Washburn, J.
Object Type: Article
System: The UNT Digital Library
Control of beam dynamics in high energy induction linacs (open access)

Control of beam dynamics in high energy induction linacs

The Advent of laser-ion-guiding in the Advanced test Accelerator along with the development of accelerator cavities optimized with respect to beam breakup coupling impedence now make it possible to consider a new class of high current, high emergy linear induction accelerators. The control of the beam breakup and other instabilities by laser guiding and by various magnetic focusing schemes will be discussed along with the scaling laws for the design of such machines to minimize the growth of the beam breakup instability. Many linacs, particularly induction linacs are limited in performance by the beam breakup (BBU) instability. The instability is found in two forms. In the first form the accelerating cavities communicate with one another through interaction with the beam and through propagation of cavity fields through the accelerator structure. In the second form which is the more virulent of the two, the cavities couple to each other only through their interactions with the beam. It is this second form of PPU that will be discussed in this paper.
Date: July 29, 1986
Creator: Caporaso, G.J.
Object Type: Article
System: The UNT Digital Library
User's manual for FENAT: a two-dimensional multigroup diffusion theory Finite Element Neutral Atom Transport code (open access)

User's manual for FENAT: a two-dimensional multigroup diffusion theory Finite Element Neutral Atom Transport code

FENAT solves the two-dimensional energy dependent diffusion equation in Cartesian (X-Y) and cylindrical/toroidal (R-Z) coordinates. The boundary conditions allowed are: vacuum, reflection, albedo and surface source. The energy variable is treated by multigroup method. The resulting multigroup diffusion equation is solved by finite element Galerkin's method with triangular element discretization of the spatial domain. The algebraic matrix equation is solved by the direct method of Crout variation of Gauss' elimination. Dynamic memory allocation has been used so that the maximum problem size is limited by the size of active core storage of the machine. When necessary, the global matrix is stored in a binary disk file. FENAT is particularly suitable for the transport of neutral atoms in fusion plasmas.
Date: July 1, 1986
Creator: Hasan, M.Z.
Object Type: Report
System: The UNT Digital Library
Remarks on the clump theory (open access)

Remarks on the clump theory

Further details are provided of a soon-to-be published dialog (Phys. Fluids 29 (July, 1986)) which discussed the role of the small scales in fluid clump theory. It is argued that the approximation of the clump lifetime which is compatible with exponentially rapid separation of adjacent orbits is inappropriate for the description of the dynamically important large scales. Various other remarks are made relating to the analytic treatment of strong drift-wave-like turbulence.
Date: July 1, 1986
Creator: Krommes, John A.
Object Type: Report
System: The UNT Digital Library
Passive correction of persistent current multipoles in superconducting accelerator dipoles (open access)

Passive correction of persistent current multipoles in superconducting accelerator dipoles

Correction of the magnetization sextupole and decapole fields with strips of superconductor placed just inside the coil winding is discussed. Calculations have been carried out for such a scheme, and tests have been conducted on a 4 cm aperture magnet. The calculated sextupole correction at the injection excitation of 330 A, 5% of full field, was expected to be 77% effective, while the measured correction is 83%, thus suggesting the scheme may be useful for future accelerators such as SSC and LHC.
Date: July 1, 1986
Creator: Fisk, H.E.; Hanft, R.A.; Kuchnir, M. & McInturff, A.D.
Object Type: Report
System: The UNT Digital Library
Heat and mass transfer analysis of a desiccant dehumidifier matrix (open access)

Heat and mass transfer analysis of a desiccant dehumidifier matrix

This report documents the SERI Single-Blow Test Facility's design, fabrication, and testing for characterizing desiccant dehumidifiers for solar cooling applications. The first test article, a silica-gel parallel-plate dehumidifier with highly uniform passages, was designed and fabricated. Transient heat and mass transfer data and pressure drop data across the dehumidifier were obtained. Available heat and mass transfer models were extended to the parallel-place geometry, and the experimental data were compared with model predictions. Pressure drop measurements were also compared with model predictions of the fully developed laminar flow theory. The comparisons between the lumped-capacitance model and the experimental data were satisfactory. The pressure drop data compared satisfactorily with the theory (within 15%). A solid-side resistance model that is more detailed and does not assume symmetrical diffusion in particles was recommended for performance. This study has increased our understanding of the heat and mass transfer in silica gel parallel-plate dehumidifiers.
Date: July 1, 1986
Creator: Pesaran, A.A.
Object Type: Report
System: The UNT Digital Library
Power transport to the PDX scoop limiter (open access)

Power transport to the PDX scoop limiter

Power transport to the PDX graphite scoop limiter was measured during both ohmic- and neutral-beam-heated discharges by observing its front face temperatures using an infrared camera. Measurements were made as a function of plasma density, current, position, fueling mode, and heating power for both co- and counter-neutral beam injection. The measured thermal load on the scoop limiter was 25 to 50% of the total plasma heating power. The measured peak front face midplane temperature was 1500/sup 0/C corresponding to a peak surface power density of 3 kW/cm/sup 2/. This power density implies an effective parallel power flow of 54 kW/cm/sup 2/ in agreement with the radial power distribution extrapolated from TVTS and calorimetry measurements. Symmetric and asymmetric thermal loads were observed. The asymmetric heat loads were predominantly skewed toward the respective ion drift directions for both co- and counter-injected beams. The results of transport calculations are consistent with the direction and magnitude of the observed asymmetries.
Date: July 1, 1986
Creator: Kugel, H.W.; Bol, K.; Budny, R.; Fonck, R.; Goldston, R.; Grek, B. et al.
Object Type: Report
System: The UNT Digital Library
Observation of impurity accumulation and concurrent impurity influx in PBX (open access)

Observation of impurity accumulation and concurrent impurity influx in PBX

Impurity studies in L- and H-mode discharges in PBX have shown that both types of discharges can evolve into either an impurity accumulative or nonaccumulative case. In a typical accumulative discharge, Zeff peaks in the center to values of about 5. The central metallic densities can be high, n/sub met//n/sub e/ approx. = 0.01, resulting in central radiated power densities in excess of 1 W/cm/sup 3/, consistent with bolometric estimates. The radial profiles of metals obtained independently from the line radiation in the soft x-ray and the VUV regions are very peaked. Concurrent with the peaking, an increase in the impurity influx coming from the edge of the plasma is observed. At the beginning of the accumulation phase the inward particle flux for titanium has values of 6 x 10/sup 10/ and 10 x 10/sup 10/ particles/cm/sup 2/s at minor radii of 6 and 17 cm. At the end of the accumulation phase, this particle flux is strongly increased to values of 3 x 10/sup 12/ and 1 x 10/sup 12/ particles/cm/sup 2/s. This increased flux is mainly due to influx from the edge of the plasma and to a lesser extent due to increased convective transport. Using the measured …
Date: July 1, 1986
Creator: Sesnic, S.S.; Fonck, R.J.; Ida, K.; Bol, K.; Couture, P.; Gammel, G. et al.
Object Type: Report
System: The UNT Digital Library
Post-disruptive plasma loss in the Princeton Beta Experiment (PBX) (open access)

Post-disruptive plasma loss in the Princeton Beta Experiment (PBX)

The free-boundary, axisymmetric tokamak simulation code TSC is used to model the transport time scale evolution and positional stability of PBX. A disruptive thermal quench will cause the plasma column to move inward in major radius. It is shown that the plasma can then lose axisymmetric stability, causing it to displace exponentially off the midplane, terminating the discharge. We verify the accuracy of the code by modeling several controlled experiments shots in PBX.
Date: July 1, 1986
Creator: Jardin, S. C.; DeLucia, J.; Okabayashi, M.; Pomphrey, N.; Reusch, M.; Kaye, S. et al.
Object Type: Report
System: The UNT Digital Library
High-spin nuclear spectroscopy (open access)

High-spin nuclear spectroscopy

High-spin spectroscopy is the study of the changes in nuclear structure, properties, and behavior with increasing angular momentum. It involves the complex interplay between collective and single-particle motion, between shape and deformation changes, particle alignments, and changes in the pairing correlations. A review of progress in theory, experimentation, and instrumentation in this field is given. (DWL)
Date: July 1, 1986
Creator: Diamond, R. M.
Object Type: Article
System: The UNT Digital Library
ICF drivers: a comparison of some new entries and old standbys. Revision 1 (open access)

ICF drivers: a comparison of some new entries and old standbys. Revision 1

There has been a great deal of progress in recent years on the development of solid state and KrF lasers, light ion diodes, and heavy ion accelerators for use as drivers in inertial confinement fusion (ICF) facilities. Two relatively new entries in the ICF driver derby are the free electron laser (FEL) and the compact torus (CT). The status and remaining technological challenges of each potential driver are described. The author discusses driver performance criteria for various reactor applications and then gives his informed opinion in a qualitative rating of the six drivers for each application.
Date: July 31, 1986
Creator: Hogan, W.J.
Object Type: Article
System: The UNT Digital Library
Scaling of current density, total current, emittance, and brightness for hydrogen negative ion sources (open access)

Scaling of current density, total current, emittance, and brightness for hydrogen negative ion sources

The atomic and molecular processes that play a principal role in negative ion formation in a hydrogen negative ion discharge are discussed. The collisions of energetic electrons with gas molecules within the discharge lead to vibrationally excited molecules. Thermal electrons in turn attach to these excited molecules and generate negative ions via the dissociative attachment process. A system geometry chosen to optimize these collision processes is discussed that consists of a high-power discharge in tandem with a low electron temperature bath, the two regions separated by a magnetic filter. The current density extracted from such a system is found to scale inversely with the system scale length provided the gas density and electron density are also increased inversely with scale length. If a system is scaled downward in size to provide a new beamlet but one with increased current density, and these beamlets are packed to fill the original dimension, the new total extracted current will exceed the original total current by the scale factor. The emittance, epsilon, of the new system remains unchanged. The brightness, J/epsilon/sup 2/, of the new system will also be increased in proportion to the scale factor. 4 refs., 2 figs.
Date: July 10, 1986
Creator: Hiskes, J.R.
Object Type: Article
System: The UNT Digital Library
Method for Assigning Sites to Projected Generic Nuclear Power Plants (open access)

Method for Assigning Sites to Projected Generic Nuclear Power Plants

Pacific Northwest Laboratory developed a method for forecasting potential locations and startup sequences of nuclear power plants that will be required in the future but have not yet been specifically identified by electric utilities. Use of the method results in numerical ratings for potential nuclear power plant sites located in each of the 10 federal energy regions. The rating for each potential site is obtained from numerical factors assigned to each of 5 primary siting characteristics: (1) cooling water availability, (2) site land area, (3) power transmission land area, (4) proximity to metropolitan areas, and (5) utility plans for the site. The sequence of plant startups in each federal energy region is obtained by use of the numerical ratings and the forecasts of generic nuclear power plant startups obtained from the EIA Middle Case electricity forecast. Sites are assigned to generic plants in chronological order according to startup date.
Date: July 1, 1986
Creator: Holter, G. M.; Purcell, W. L.; Shutz, M. E. & Young, J. R.
Object Type: Report
System: The UNT Digital Library