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Neutral injection experiments on the ISX-B tokamak (open access)

Neutral injection experiments on the ISX-B tokamak

The following topics are described: (1) review of confinement scaling in ISX-B with strong neutral injection in clean plasmas, (2) discussion of observed energy confinement improvement in slightly contaminated discharges (factor less than or equal to 2), and (3) preliminary evaluation of confinement with balanced neutral beam injection. (MOW)
Date: January 1, 1983
Creator: Scott, S.D.
System: The UNT Digital Library
National Low-Temperature Neutron-Irradiation Facility (open access)

National Low-Temperature Neutron-Irradiation Facility

The Materials Sciences Division of the United States Department of Energy will establish a National Low Temperature Neutron Irradiation Facility (NLTNIF) which will utilize the Bulk Shielding Reactor (BSR) located at Oak Ridge National Laboratory. The facility will provide high radiation intensities and special environmental and testing conditions for qualified experiments at no cost to users. This report describes the planned experimental capabilities of the new facility.
Date: August 1, 1983
Creator: Coltman, R.R. Jr.; Klabunde, C.E. & Young, F.W. Jr.
System: The UNT Digital Library
Montecarlo studies of t quarks (open access)

Montecarlo studies of t quarks

In this report I describe some of the results of a Montecarlo study with the Program ISAJET done in collaboration with S. Aronson, F. Paige and D. Weygand at BNL. Top quarks can be produced by QCD processes such as q anti q ..-->.. t anti t or gg ..-->.. t anti t or from the decay W/sup +-/ ..-->.. t anti b (anti tb); the cross section depends on the t mass and the center of mass energy. At ..sqrt..s = 540 GeV W decays produce more t quarks if 40 GeV < m/sub t/ < 60 GeV than QCD processes because the W branching ratio does not decrease rapidly with the t mass. The branching ratio is given by B = ..gamma../(3 + ..gamma..) where ..gamma.. = (1 - m/sub t//m/sub W/)/sup 2/)/sup 2/ (1 + 1/2 (m/sub t//m/sub W/)/sup 2/)/sup 2/ from which one obtains B = 21% for m/sub t/ = 30 GeV and B = 8.7% for m/sub t/ = 60 GeV. In Figure 1 we show the expected cross section as a function of m/sub t/ at ..sqrt..s = 540 GeV and at ..sqrt..s = 2 TeV. The W decay process is clearly dominant …
Date: January 1, 1983
Creator: Protopopescu, S.D.
System: The UNT Digital Library
Characterization of the TEXTOR plasma edge using deposition probe techniques (open access)

Characterization of the TEXTOR plasma edge using deposition probe techniques

Carbon and single crystal silicon passive deposition probes were used to measure the characteristics of the plasma edge region of the TEXTOR tokamak. Analysis of the probes was done by Rutherford backscattering for impurities and nuclear reaction analysis and elastic recoil detection for hydrogen isotopes. Plasma fluxes and energies in the edge were measured using probe techniques. The principal impurities in the plasma edge were determined and their behavior as a function of time and position was measured. Measurements were also made of in situ erosion rates. The results are compared with independent measurements of other plasma parameters to study possible impurity introduction mechanisms. This work represents the first deposition probe measurements made in the plasma edge of TEXTOR.
Date: October 1, 1983
Creator: Zuhr, R.A.
System: The UNT Digital Library
Zero-field. mu. SR and low-temperature. mu. /sup +/ diffusivity in copper (open access)

Zero-field. mu. SR and low-temperature. mu. /sup +/ diffusivity in copper

In this paper the history of ..mu../sup +/ diffusion studies in copper, with particular emphasis on the increased low-temperature diffusivity which has been known for several years now, is reviewed. The theory and practice of the zero-field ..mu..SR method, which has come into increasing favor in the study of muon diffusion and trapping in metals, is surveyed, and its application to the low-temperature copper problem is discussed. 26 references.
Date: April 1, 1983
Creator: Clawson, C.W.
System: The UNT Digital Library
Theory of elementary excitations in intermediate valence materials (open access)

Theory of elementary excitations in intermediate valence materials

We review the formalism for calculating the properties of systems represented by an Anderson lattice Hamiltonian. First, a mean-field theory for the one electron Green's function is presented and then extended to include spin and charge fluctuations which lead to a many-body resonance near the Fermi level. The dynamical spin susceptibility and neutron scattering cross section are also evaluated. Finally, we present a calculation which indicates the possibility of a Cooper-pairing mechanism induced by electron correlations.
Date: October 1, 1983
Creator: Fedro, A.J. & Sinha, S.K.
System: The UNT Digital Library
Intense positron beams: linacs. Preworkshop copy (open access)

Intense positron beams: linacs. Preworkshop copy

Beams of monoenergetic positrons with energies of a few eV to many keV have been used in experiments in atomic physics, solid state physics and materials science. The production of positron beams from a new source, an electron linac, is described. Intense, pulsed beams of low-energy positrons have been produced by a high-energy beam from an electron linac. The production efficiency, moderator geometry, beam spot size and other positron beam parameters have been determined for electrons with energies from 60 to 120 MeV. Low-energy positron beams produced with a high-energy electron linac can be of much higher intensity than those beams currently derived from radioactive sources. These higher intensity beams will make possible positron experiments previously infeasible.
Date: September 1, 1983
Creator: Howell, R. H.; Alvarez, R. A.; Woodle, K. A.; Dhawan, S.; Egan, P. O.; Hughes, V. W. et al.
System: The UNT Digital Library
Characteristics of a long-pulse (30-s), high-power (4-MW) ion source for neutral beam injection (open access)

Characteristics of a long-pulse (30-s), high-power (4-MW) ion source for neutral beam injection

A quasi-steady-state ion source has been developed for neutral beam injection applications. It is of the duoPIGatron type designed for delivering 50 A of hydrogen ions at 80 keV for 30-s-long pulses. Ion beams of 40 A at 75 keV were extracted for pulse lengths up to 30 s, maintaining excellent optical quality in the beam for the entire pulse duration. The design features and operational characteristics of the ion source are elaborated.
Date: January 1, 1983
Creator: Menon, M. M.; Barber, G. C.; Combs, S. K.; Dagenhart, W. K.; Gardner, W. L.; Haselton, H. H. et al.
System: The UNT Digital Library
Comparison of the Aerospace Systems Test Reactor loss-of-coolant test data with predictions of the 3D-AIRLOCA code (open access)

Comparison of the Aerospace Systems Test Reactor loss-of-coolant test data with predictions of the 3D-AIRLOCA code

This paper compares the predictions of the revised 3D-AIRLOCA computer code to those data available from the Aerospace Systems Test Reactor's (ASTR's) loss-of-coolant-accident (LOCA) tests run in 1964. The theoretical and experimental hot-spot temperature responses compare remarkably well. In the thirteen cases studied, the irradiation powers varied from 0.4 to 8.87 MW; the irradiation times were 300, 1540, 1800, and 10/sup 4/ s. The degrees of agreement between the data and predictions provide an experimental validation of the 3D-AIRLOCA code.
Date: January 1, 1983
Creator: Warinner, D. K.
System: The UNT Digital Library
Conservation laws in the monopole-fermion system (open access)

Conservation laws in the monopole-fermion system

It is shown that the monopole induced baryon number non-conservation is a necessary consequence of the exact conservation laws of the full four dimensional fermion-gauge field-Higgs system and properties of the J=0 partial wave fermions. It is also shown that the charge associated with the unbroken gauge symmetry is exactly conserved in the monopole-fermion interaction. 11 references.
Date: December 1, 1983
Creator: Sen, A.
System: The UNT Digital Library
Human factors in remote control engineering development activities (open access)

Human factors in remote control engineering development activities

Human factors engineering, which is an integral part of the advanced remote control development activities at the Oak Ridge National Laboratory, is described. First, work at the Remote Systems Development Facility (RSDF) has shown that operators can perform a wide variety of tasks, some of which were not specifically designed for remote systems, with a dextrous electronic force-reflecting servomanipulator and good television remote viewing capabilities. Second, the data collected during mock-up remote maintenance experiments at the RSDF have been analyzed to provide guidelines for the design of human interfaces with an integrated advanced remote maintenance system currently under development. Guidelines have been provided for task allocation between operators, remote viewing systems, and operator controls. 6 references, 5 figures, 2 tables.
Date: January 1, 1983
Creator: Clarke, M.M.; Hamel, W.R. & Draper, J.V.
System: The UNT Digital Library
Review of tellurium release rates from LWR fuel elements under accident conditions (open access)

Review of tellurium release rates from LWR fuel elements under accident conditions

Although fission product tellurium presents a potentially significant radiohazard, its release and transport in source-term experiments is frequently overlooked because it does not possess a readily measurable, gamma emission; moreover, a recent study emphasized noble gas, iodine and cesium release from LWR fuel elements because of the large data base that exists for these materials. Some new tests show that in some cases tellurium may be held up in core material to a greater degree than previously assumed - an observation that prompts a careful reappraisal of the existing tellurium-release data and its chemical foundation.
Date: January 1, 1983
Creator: Lorenz, R. A.; Beahm, E. C. & Wichner, R. P.
System: The UNT Digital Library
Analysis of production data from the Krafla geothermal field, Iceland (open access)

Analysis of production data from the Krafla geothermal field, Iceland

The analysis of flow rate and enthalpy data from several wells completed in the same two-phase zone of Krafla geothermal reservoir has yielded consistent relative permeability parameters. It is found that k/sub rl/ + k/sub rv/ = 1 over the entire range of two-phase flow conditions from immobile liquid to immobile vapor. The available data provide relative permeability parameters as a function of flowing enthalpy only. The relationship between flowing enthalpy and in-place vapor saturation remains unknown, so that the relative permeability information obtained is of limited value for quantitative modeling of geothermal reservoir performance. Numerical simulation of flow rate and enthalpy transients has yielded excellent matches to production data from well 12. However, there is little information about the reservoir which can be deduced in an unambiguous way, because the field data could be matched with a variety of rather different parameter choices. The only unambiguous piece of information obtained is that the water injected into the well during drilling and completion remains in the vicinity of the wellbore during several weeks of warmup.
Date: December 1, 1983
Creator: Pruess, K.; Bodvarsson, G. S. & Stefansson, V.
System: The UNT Digital Library
Parametric system studies of candidate TF coil system options for the Tokamak Fusion Core Experiment (TFCX) (open access)

Parametric system studies of candidate TF coil system options for the Tokamak Fusion Core Experiment (TFCX)

System studies were performed to determine the sensitivity of hybrid and superconducting toroidal field (TF) coil system options to maximum field at the TF coil and to field enhancement due to resistive insert coils. The studies were performed using Tokamak Fusion Core Experiment (TFCX) design assumptions, guidelines, and criteria and involved iterative execution of the Fusion Engineering Design Center (FEDC) systems code, magnetohydrodynamics (MHD) equilibrium code, and EFFI (a code to evaluate magnetic field strength). The results indicate that for TFCX with no minimum wall loading specified, a design point chosen solely on the basis of cost would likely be in the low-field region of design space where the cost advantage of hybrids is least apparent. However, as the desired neutron wall loading increases, the hybrid option suggests an increasing cost advantage over the all-superconducting option; this cost advantage is countered by increased complexity in design - particularly in assembly and maintenance.
Date: January 1, 1983
Creator: Reiersen, W. T.; Flanagan, C. A. & Miller, J. B.
System: The UNT Digital Library
Electrical design of a high current density air-core reversed-field pinch ZTP (open access)

Electrical design of a high current density air-core reversed-field pinch ZTP

This paper describes the electrical design of a small, high current density (10 MA/m/sup 2/) toroidal reversed-field Z-Pinch (RFP) presently being constructed at Los Alamos. Special purpose magnetic field programs were used to calculate self and mutual inductances for the poloidal field windings. The network analysis program MINI-SCEPTRE was then used to predict plasma current, including the interaction between toroidal and poloidal field circuits, as described by the Bessel function model for RFP's. Using these programs, coil geometry was obtained for minimal field errors and the pulse power systems were optimized to minimize equilibrium control power. Results of computer modeling and implementation of the electrical circuits are presented.
Date: January 1, 1983
Creator: Reass, W. A.; Melton, J. G. & Gribble, R. F.
System: The UNT Digital Library
NCIS - a Nuclear Criticality Information System (overview) (open access)

NCIS - a Nuclear Criticality Information System (overview)

A Nuclear Criticality Information System (NCIS) is being established at the Lawrence Livermore National Laboratory (LLNL) in order to serve personnel responsible for safe storage, transport, and handling of fissile materials and those concerned with the evaluation and analysis of nuclear, critical experiments. Public concern for nuclear safety provides the incentive for improved access to nuclear safety information.
Date: July 1, 1983
Creator: Koponen, B. L. & Hampel, V. E.
System: The UNT Digital Library
Meson radiation from quark-gluon plasma (open access)

Meson radiation from quark-gluon plasma

Meson formation and radiation at the surface of quark-gluon plasma are studied by making use of the chromoelectric flux tube model. The effect of the surface meson radiation on the hydroexpansion of the plasma fluid is also discussed.
Date: November 1, 1983
Creator: Matsui, T.; Banerjee, B. & Glendenning, N.K.
System: The UNT Digital Library
Los Alamos Omega West Reactor (open access)

Los Alamos Omega West Reactor

A description is given of the Omega West Reactor and associated experimental facilities, followed by a brief discussion of recent usage, new experiments, and future prospects.
Date: January 1, 1983
Creator: Lyle, A. R.; Williams, H. T. & Bunker, M. E.
System: The UNT Digital Library
Are 0. 1%-accurate gamma-ray assays possible for /sup 235/U solutions (open access)

Are 0. 1%-accurate gamma-ray assays possible for /sup 235/U solutions

The factors influencing the accuracy of passive gamma-ray assay of uniform, homogeneous solution samples have been studied in some detail, particularly for the assay of /sup 235/U in uranium solutions. Factors considered are the overall long-term electronic stability, the information losses caused by the rate-related electronic processes of pulse pileup and dead-time, and the self-attenuation of gamma rays within the samples. Both experimental and computational studies indicate that gamma-ray assay procedures for solution samples of moderate size (from approx. 10 to perhaps a few hundred milliliters) are now capable of accuracies approaching 0.1% in many practical cases.
Date: January 1, 1983
Creator: Parker, J.L.
System: The UNT Digital Library
Physical response of backfill materials to mineralogical changes in a basalt environment. [Sand-clay mixture containing 25% bentonite] (open access)

Physical response of backfill materials to mineralogical changes in a basalt environment. [Sand-clay mixture containing 25% bentonite]

Backfill materials surrounding waste canisters in a high-level nuclear waste repository are capable of ensuring very slow flow of groundwater past the canisters, and thereby increase the safety of the repository. However, in the design of a repository it will be necessary to allow for possible changes in the backfill. In this experimental program, changes in permeability, swelling behavior, and plastic behavior of the backfill at the temperatures, pressures, and radiation levels expected in a repository are investigated. The emphasis is on investigation of relevant phenomena and evaluation of experimental procedures for use in licensing procedures. The permeability of a slightly compacted sand-clay mixture containing 25% bentonite, with a dry bulk density of 1.59 g/cm/sup 3/, was determined to be 0.9 x 10/sup -18/ m/sup 2/ in liquid water at 25 and 200/sup 0/C, respectively. This is sufficiently low to demonstrate the potential effectiveness of proposed materials. In practice, fractures in the host rock may form short circuits around the backfill, so an even lower flow rate is probable. However, alteration by any of several mechanisms is expected to change the properties of the backfill. Crushed basalt plus bentonite is a leading candidate backfill for a basalt repository. Experiments show …
Date: January 1, 1983
Creator: Couture, R.A. & Seitz, M.G.
System: The UNT Digital Library
Recent results from the PEP4-TPC on quark fragmentation (open access)

Recent results from the PEP4-TPC on quark fragmentation

The physics goals for the PEP-4/PEP-9 experiment concentrate on two areas: the fragmentation properties of quarks and gluons produced in e+e- annihilation, and the investigation of hadron production in 2-photon collisions. Only the first of these topics is addressed. Despite the many successes of QCD in the description of deep inelastic reactions, the basic fragmentation process of quarks and gluons is not very well understood. This lack of knowledge has been shown to jeopardize precise test of QCD, such as the accurate determination of the strong coupling constant. With its ability to disentangle complex hadronic events and to identify most of the final state particles, the TPC allows new and more sensitive tests of fragmentation models. A brief description of the detector is given and particle identification by ionization energy loss is described. Next, the inclusive production of stable hadrons and of resonances is discussed, and limits on the inclusive production of fractional charged particles are given. A new analysis of long-range correlations in e+e- annihilation is given.
Date: November 12, 1983
Creator: Hofmann, W.
System: The UNT Digital Library
Work function dependence of surface produced H/sup -/ in the presence of a plasma (open access)

Work function dependence of surface produced H/sup -/ in the presence of a plasma

The maximum H/sup -/ flux from a netatively biased converter cathode occurs at the work function minimum. A cesiated hydrogen plasma produces a partially-cesiated surface at the converter. The cesium coverage can be be controlled by the cesium partial pressure, the bias on the converter and the plasma density, while the work function of the converter surface is measured by the photo-electric effect, using a bright light source and a series of filters. The angular dependence is measured by rotating the converter.
Date: November 1, 1983
Creator: Wada, M.; Pyle, R. V. & Stearns, J. W.
System: The UNT Digital Library
Models and simulations (open access)

Models and simulations

On-line mathematical models have been used successfully for computer controlled operation of SPEAR and PEP. The same model control concept is being implemented for the operation of the LINAC and for the Damping Ring, which will be part of the Stanford Linear Collider (SLC). The purpose of this paper is to describe the general relationships between models, simulations and the control system for any machine at SLAC. The work we have done on the development of the empirical model for the Damping Ring will be presented as an example.
Date: September 1, 1983
Creator: Lee, M. J.; Sheppard, J. C.; Sullenberger, M. & Woodley, M. D.
System: The UNT Digital Library
Monopole catalysis: an overview (open access)

Monopole catalysis: an overview

A summary of the talks presented in the topological workshop on monopole catalysis at this conference is given. We place special emphasis on the conservation laws which determine the allowed monopole-fermion interactions and on catalysis as a probe of the structure of a grand unified theory. 11 references.
Date: November 1, 1983
Creator: Dawson, S.
System: The UNT Digital Library