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The multipulse Thomson scattering diagnostic on the DIII-D tokamak (open access)

The multipulse Thomson scattering diagnostic on the DIII-D tokamak

This paper describes the design and operation of a 40-spatial channel Thomson scattering system that uses multiple 20 Hz Nd:YAG lasers to measure the electron temperature and density profiles periodically throughout an entire plasma discharge. Interference filter polychromators disperse the scattered light which is detected by silicon avalanche photodiodes. The measurable temperature range from 10 eV to 20 keV and the minimum detectable density is about 2 {times} 10{sup 18} m{sup {minus}3}. Laser control and data acquisition are performed in real-time by a VME-based microcomputer. Data analysis is performed by a MicroVAX 3400. Unique features of this system include burst mode'' operation, where multiple lasers are fired in rapid succession (< 10 KHz), real-time analysis capability, and laser beam quality and alignment monitoring during plasma operation. Results of component testing, calibration, and plasma operation are presented. 8 refs. 6 figs.
Date: September 1, 1991
Creator: Carlstrom, T. N.; Campbell, G. L.; DeBoo, J. C.; Evanko, R. G.; Evans, J.; Greenfield, C. M. et al.
System: The UNT Digital Library
Prospects of physics at CDF with the SVX (open access)

Prospects of physics at CDF with the SVX

During next physics run CDF will strongly enhance its heavy flavor tagging capabilities with the installation of a silicon vertex detector (SVX), that will allow precise measurements of secondary decay vertices in the plane transverse to the beam (impact parameter resolution {approx equal} 12 {mu}m). We expect this detector to have a significant impact on b-physics (c{tau}{sub B} {approx equal} 350 {mu}m) and top search. In the following we will discuss CDF prospects for top search and for CP violation asymmetry measurements in the B-sector. 16 refs., 5 figs., 1 tabs.
Date: September 1, 1991
Creator: Dell'Agnello, S.
System: The UNT Digital Library
A cryogenic system design for the international thermonuclear experimental reactor (ITER) (open access)

A cryogenic system design for the international thermonuclear experimental reactor (ITER)

A conceptual design for ITER was completed last year. The author developed a suitable cryogenic system for ITER as part of this conceptual design effort. An overview of the design is reported. Emphasis is on the fact that cryogenics is a mature science, and a system supporting ITER needs can be made from time-proven components without loss of efficiency or reliability. Because of the large size of the ITER cryogenic system, large numbers of compressors and expanders must be used. Very high reliability is assured by arranging these components in parallel banks where servicing of individual components can be done without interruption of operations. This and other ideas based on the author's experience with Mirror Fusion Test Facility (MFTF) operations are described. 5 refs., 3 figs.
Date: September 25, 1991
Creator: Slack, D.S.
System: The UNT Digital Library
Dilepton (e sup + e sup minus ) production recent pp and pd studies with DLS at Berkeley (open access)

Dilepton (e sup + e sup minus ) production recent pp and pd studies with DLS at Berkeley

The use of dileptons as probes of hot, dense hadronic matter is described. Preliminary results on dileptons produced in p-p and p-d interactions at the Bevalac are presented along with potential ramifications for existing model calculations of dileptons at these energies. Future directions of the dilepton program at Berkeley are outlined. 14 refs., 3 figs.
Date: September 1, 1991
Creator: Schroeder, L. S.
System: The UNT Digital Library
Polarization spectroscopy of tokamak plasmas (open access)

Polarization spectroscopy of tokamak plasmas

Measurements of polarization of spectral lines emitted by tokamak plasmas provide information about the plasma internal magnetic field and the current density profile. The methods of polarization spectroscopy, as applied to the tokamak diagnostic, are reviewed with emphasis on the polarimetry of motional Stark effect in hydrogenic neutral beam emissions. 25 refs., 7 figs.
Date: September 1, 1991
Creator: Wroblewski, D.
System: The UNT Digital Library
A prototype on-line work procedure system for radioisotope thermoelectric generator production (open access)

A prototype on-line work procedure system for radioisotope thermoelectric generator production

An on-line system to manage work procedures is being developed to support radioisotope thermoelectric generator (RTG) assembly and testing in a new production facility. This system implements production work procedures as interactive electronic documents executed at the work site with no intermediate printed form. It provides good control of the creation and application of work procedures and provides active assistance to the worker in performing them and in documenting the results. An extensive prototype of this system is being evaluated to ensure that it will have all the necessary features and that it will fit the user's needs and expectations. This effort has involved the Radioisotope Power Systems Facility (RPSF) operations organization and technology transfer between Westinghouse Hanford Company (Westinghouse Hanford) and EG G Mound Applied Technologies Inc. (Mound) at the US Department of Energy (DOE) Mound Site. 1 ref.
Date: September 1, 1991
Creator: Kiebel, G.R.
System: The UNT Digital Library
The q q meson states with J sup PC = 2 sup ++ and 0 sup ++ (open access)

The q q meson states with J sup PC = 2 sup ++ and 0 sup ++

The lowest mesons made up of a light quark and a strange quark produced from a K beam show a good agreement with expectations of the quark model. This good agreement leads to the prediction of the light isoscalar and isovector states and the isoscalar s{bar s} states. Except for one mystery The X(1590) the 2{sup ++} states seems to be well described by the expected ideally mixed q{bar q} states up to 2. 0 GeV. Above 2.0 GeV a new degree of freedom seems to be excited with respect to the breakdown of the OZI rule in production of 2{sup ++} resonances that decay into {phi}{phi}. This is to be contrasted with the situation for the O{sup ++} isoscalar states which seems to show a new degree of freedom for its mesons in its ground state. One might conclude that since the O{sup ++} glueball is predicted by lattice calculations to be degenerate with the s{bar s} O{sup ++} meson, that the very unusual assortment of isoscalar O{sup ++} mesons are due to glueball mixing.
Date: September 26, 1991
Creator: Longacre, R. S.
System: The UNT Digital Library
Ferrocyanide-containing waste tanks: Ferrocyanide chemistry and reactivity (open access)

Ferrocyanide-containing waste tanks: Ferrocyanide chemistry and reactivity

The complexing constant for hexacyano-iron complexes, both Fe(2) and Fe(3), are exceptionally large. The derived transition metal salts or double salts containing alkali metal ions are only slightly soluble. The various nickel compounds examined in this study, i.e., those predicted to have been formed in the Hanford waste scavenging program, are typical examples. In spite of their relative stability towards most reagents under ambient conditions, they are all thermodynamically unstable towards oxidation and react explosively with oxidants such as nitrate or nitrate salts when heated to temperatures in excess of 200{degree}C. 42 refs., 5 figs., 3 tabs.
Date: September 1, 1991
Creator: Scheele, R. D.; Burger, L. L.; Tingey, J. M.; Bryan, S. A.; Borsheim, G. L.; Simpson, B. C. et al.
System: The UNT Digital Library
Search for W prime and Z prime at CDF (open access)

Search for W prime and Z prime at CDF

We have searched for heavy charged and neutral vector bosons via the decays W{prime} {yields} ev, W{prime} {yields} {mu}v, Z{prime} {yields} {mu}{mu} in p{bar p} collisions at {radical}s = 1.8 TeV, using data taken with the collider Detector at Fermilab. The nonobservation of these processes leads to a lower limit (95% confidence level) of 520 GeV/c{sup 2} on the mass of the W{prime} and of 412 GeV/C{sup 2} on the mass of the Z{prime}, assuming standard model coupling to fermions. 12 refs., 6 figs., 1 tab.
Date: September 1, 1991
Creator: Fuess, T.
System: The UNT Digital Library
The Scalable Coherent Interface and related standards projects (open access)

The Scalable Coherent Interface and related standards projects

The Scalable Coherent Interface (SCI) project (IEEE P1596) found a way to avoid the limits that are inherent in bus technology. SCI provides bus-like services by transmitting packets on a collection of point-to-point unidirectional links. The SCI protocols support cache coherence in a distributed-shared-memory multiprocessor model, message passing, I/O, and local-area-network-like communication over fiber optic or wire links. VLSI circuits that operate parallel links at 1000 MByte/s and serial links at 1000 Mbit/s will be available early in 1992. Several ongoing SCI-related projects are applying the SCI technology to new areas or extending it to more difficult problems. P1596.1 defines the architecture of a bridge between SCI and VME; P1596.2 compatibly extends the cache coherence mechanism for efficient operation with kiloprocessor systems; P1596.3 defines new low-voltage (about 0.25 V) differential signals suitable for low power interfaces for CMOS or GaAs VLSI implementations of SCI; P1596.4 defines a high performance memory chip interface using these signals; P1596.5 defines data transfer formats for efficient interprocessor communication in heterogeneous multiprocessor systems. This paper reports the current status of SCI, related standards, and new projects. 16 refs.
Date: September 1, 1991
Creator: Gustavson, D.B.
System: The UNT Digital Library
Bootstrap and fast wave current drive for tokamak reactors (open access)

Bootstrap and fast wave current drive for tokamak reactors

Using the multi-species neoclassical treatment of Hirshman and Sigmar we study steady state bootstrap equilibria with seed currents provided by low frequency (ICRF) fast waves and with additional surface current density driven by lower hybrid waves. This study applies to reactor plasmas of arbitrary aspect ratio. IN one limit the bootstrap component can supply nearly the total equilibrium current with minimal driving power (< 20 MW). However, for larger total currents considerable driving power is required (for ITER: I{sub o} = 18 MA needs P{sub FW} = 15 MW, P{sub LH} = 75 MW). A computational survey of bootstrap fraction and current drive efficiency is presented. 11 refs., 8 figs.
Date: September 1, 1991
Creator: Ehst, D.A.
System: The UNT Digital Library
Tracking and vertex finding with drift chambers and neural networks (open access)

Tracking and vertex finding with drift chambers and neural networks

Finding tracks, track vertices and event vertices with neural networks from drift chamber signals is discussed. Simulated feed-forward neural networks have been trained with back-propagation to give track parameters using Monte Carlo simulated tracks in one case and actual experimental data in another. Effects on network performance of limited weight resolution, noise and drift chamber resolution are given. Possible implementations in hardware are discussed. 7 refs., 10 figs.
Date: September 1, 1991
Creator: Lindsey, C.
System: The UNT Digital Library
Isolated single and double direct photon production at CDF (open access)

Isolated single and double direct photon production at CDF

We present measurements of isolated direct phonon production in {bar p}p collisions at {radical}s = 1.18 TeV from the 1988--89 run of the Collider Detection at Fermilab (CDF). Quantum Chromodynamics is tested against measurements of the transverse momentum spectrum of single photon production ({bar p}p {yields} {gamma} + X), double photon production ({bar p}p {yields} {gamma}{gamma} + X), and the distribution of cos{theta} * in photon-jet events ({bar p}p {yields} {gamma}{sub J} + X). We also present a measurement of the isolated production ratio of {eta} and {pi}{sup 0} mesons ({bar p}p {yields} {eta} + X)/({bar p}p {yields} {pi}{sup 0} + X) = 1.02 {plus minus}.15(stat){plus minus}.23(sys). 9 refs., 2 figs.
Date: September 1, 1991
Creator: Harris, R.
System: The UNT Digital Library
Potential for using a six-phase alternating current power supply system for in situ vitrification (open access)

Potential for using a six-phase alternating current power supply system for in situ vitrification

In situ vitrification (ISV) has been identified as a potential treatment technology for stabilizing underground tanks at Hanford and other US Department of Energy (DOE) sites. A key requirement for this application is an electrical system that can supply the power needed to vitrify a tank in a single setting. This paper describes an engineering-scale test conducted at the Pacific Northwest Laboratory (PNL) to assess the efficiency of a six-electrode, six-phase energy supply system in melting soil. The test was conducted with a 30-kW six-phase system. Based on the test results, a six-electrode, six-phase system shows potential for scaleup to larger systems. 5 refs., 5 figs., 2 tabs.
Date: September 1, 1991
Creator: Richardson, R.L.
System: The UNT Digital Library
Testing of advanced ceramic fabric heat pipe for a Stirling engine (open access)

Testing of advanced ceramic fabric heat pipe for a Stirling engine

The development and application of Stirling engines for space power production requires concomitant development of an advanced heat rejection system. We are currently involved in the design, development, and testing of advanced ceramic fabric (ACF) water heat pipes for optimal heat rejection from the Stirling cycle without the use of hazardous working fluids such as mercury. Our testing to-date has been with a 200-{mu}m thick titanium heat pipe utilizing Nextel {trademark} fabric as both the outer structural component and as a wick. This heat pipe has been successfully started up from a frozen condition against a negative 4 degree tilt (i.e., fluid return to evaporator was against gravity), with 75 W heat input, in ambient air. In a horizontal orientation, up to 100 W heat input was tolerated without experiencing dryout. 7 refs., 5 figs., 2 tabs.
Date: September 1, 1991
Creator: Antoniak, Z.I.; Webb, B.J. & Bates, J.M.
System: The UNT Digital Library
An sup 15 N NMR method for the characterization of organic sulfur in coal and coal products via iminosulfurane formation (open access)

An sup 15 N NMR method for the characterization of organic sulfur in coal and coal products via iminosulfurane formation

The indirect of organic sulfur by {sup 15}N NMR spectroscopy in the solid state is feasible by facile reactions providing the iminosulfurane structures. Unfortunately, nitrogen chemical shifts appear to be insufficiently sensitive to the nature of the sulfur substituent to be useful for structural studies. Further work is underway to determine the {sup 15}N chemical shifts of iminosulfuranes formed from dibenzothiophene, 4-4{prime}-dimethoxydiphenyl sulfide, and a sulfur-containing, methylated asphaltene to determine the sensitivity of {sup 15}N shifts to a broader variation of aromatic structure. Although double cross-polarization experiments or rotational echo experiments could make use of iminosulfurane formation for detection of carbon in proximity to sulfur, the difficulties in quantitation using these methods are not encouraging for coal product mixtures. 6 refs., 1 fig., 1 tab.
Date: September 1, 1991
Creator: Franz, J. A.; Lamb, C. N. & Linehan, J. C.
System: The UNT Digital Library
X-ray reflectivity studies of the metal/solution interphase (open access)

X-ray reflectivity studies of the metal/solution interphase

We have designed an electrochemical cell that permits x-ray scattering studies in a transmission geometry under in-situ electrochemical control and have performed x-ray specular reflectivity studies of several metal/solution interphases as a function of electrochemical potential. For the copper/solution interphase, we found that the reflectivity changes upon oxidation and reduction, indicating a phase transition between copper and copper oxide at the interphase. We also found that the thickness of the pure copper and the roughness of the interfaces exhibited electrochemical irreversibility that is consistent with the potentials for the oxidation waves in the anodic sweep and the reduction waves in the cathodic sweep of the voltammogram. A standard Fresnel expression for the x-ray specular reflectivity was applied in the data analysis, and a smoothly varying Lorentzian interface profile was used for the individual rough interfaces. Furthermore, an incoherent average was used to include the effect of correlated roughness between a pair of interfaces. Preliminary results are also presented for the silver/solution and platinum/solution interphases. 14 refs., 9 figs., 2 tabs.
Date: September 1, 1991
Creator: You, H.; Nagy, Z.; Melendres, C. A.; Zurawski, D. J.; Chiarello, R. P.; Yonco, R. M. et al.
System: The UNT Digital Library
Phase stability in Be-Nb and Be-Nb-Zr intermetallics (open access)

Phase stability in Be-Nb and Be-Nb-Zr intermetallics

Sputter deposition of Be-Nb alloys at low temperature (30{degrees}C) produces an amorphous phase for compositions >5 at.% Nb. A metastable crystalline phase which can be considered a highly faulted form of the Be{sub 12}Nb occurs at higher deposition temperatures or by low-temperature annealing of the amorphous phase. Because of structural similarities, this metastable phase is a precursor to the formation of either Be{sub 12}Nb or Be{sub 17}Nb{sub 2} upon high temperature annealing. There was no evidence of the Be{sub 5}Nb phase which has been postulated on some phase diagrams. The Be{sub 12}Nb phase can accomodate considerable Zr in the structure and the Be{sub 13}Zr can accomodate Nb into its structure. The Be{sub 13}Zr becomes the predominant phase when the Zr/Nb composition ratio > 1. High temperature annealing of the ternary results in dual-phase regions of Be{sub 12}(Nb,Zr) + Be{sub 17}(NbZr){sub 2} or Be{sub 13}(Zr,Nb) + Be{sub 17}(Zr,Nb){sub 2}, but the coexistence of Be{sub 12}(Nb,Zr) + Be{sub 13}(Zr,Nb) has not been observed. 10 refs., 5 figs.
Date: September 1, 1991
Creator: Brimhall, J.L.; Charlot, L.A. & Bruemmer, S.M.
System: The UNT Digital Library
Towards the next linear collider (open access)

Towards the next linear collider

This report discusses design choices for the next generation linear colliders. (LSP)
Date: September 1, 1991
Creator: Irwin, J.
System: The UNT Digital Library
First order tune shift calculations for transverse betatron dynamics (open access)

First order tune shift calculations for transverse betatron dynamics

An effective Hamiltonian, with non-linear magnetic multipole terms and momentum dispersion contributions, is used to obtain the first order tune-shift results for transverse betatron motion for protons in the Superconducting Super Collider (SSC). This Hamiltonian is represented in terms of action angle variables, and analytical results are obtained using symbolic algebra methods. Mathematical derivations of the transverse multipole expansion and of the transverse betatron equations, using an invariant action and curvilinear coordinates, are given in the appendices. Numerical and graphical tune-space results are given that illustrate the dependence of tune-shifts on injection amplitude and momentum spread. 10 refs., 7 figs.
Date: September 1, 1991
Creator: Garavaglia, T.
System: The UNT Digital Library
A comparison of the neutron response of CR-39 made by different manufacturers (open access)

A comparison of the neutron response of CR-39 made by different manufacturers

CR-39 was obtained from American Acrylics and Plastics, Inc. (A.A), N. E. Technology, Ltd. (N.E), and Tech/Ops Landauer, Inc. (LT). The dosemeters were exposed to radioisotopic neutron sources at SLAC, and moderated {sup 252}Cf at ORNL. The A.A. and N.E. dosemeters were electrochemically etched (pre-etch in 6.5 N KOH at 60{degrees}C for 1 hour and 45 minutes, a 5 hour etch at 3000 V and 60 Hz, a 23 minute blow-up step at 2 kHz and a post-etch for 15 minutes). Track densities were determined with the Homann Track Size Image Analyzer. The LT dosemeters were chemically etched in 5.5 N NaOH at 70{degrees}C for 15.5 hours. Some A.A., N.E., and LT dosemeters were etched in 6.25 N NaOH at 70{degrees}C for 6 hours. A pre-etch step in 60% methanol and 40% NaOH at 70{degrees}C for 1 hour was added for some N.E. dosemeters. The results of these studies are reported in this paper. 3 refs., 2 figs., 2 tabs.
Date: September 1, 1991
Creator: Ipe, N.E.; Liu, J.C. (Stanford Linear Accelerator Center, Menlo Park, CA (United States)); Buddemeier, B.R. (Lawrence Livermore National Lab., CA (United States)); Miles, C.J. (Radiation Detection Co., Sunnyvale, CA (United States)) & Yoder, R.C. (Tech/OPS Landauer, Inc., Glenwood, IL (United States))
System: The UNT Digital Library
Effects of ambient background gases on YBCO plume propagation under film growth conditions: Spectroscopic, ion probe, and fast photographic studies (open access)

Effects of ambient background gases on YBCO plume propagation under film growth conditions: Spectroscopic, ion probe, and fast photographic studies

The formation, composition, and propagation of KrF laser-produced plasmas from Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-x} have been studied with emphasis on topics relevant to film growth by pulsed-laser deposition. Spatially and temporally resolved, high-resolution optical absorption and emission spectroscopy, fast ion probes, and fast photography (obtained with a gated, image-intensified CCD array detector (ICCD)) are employed to investigate both emitting and non-emitting species in the laser plume as well as the overall shape and propagation of the laser plasma in background gases of oxygen and xenon. Transient optical absorption spectroscopy is applied to study the composition of the plume of ejected material from the dense layer near the target surface to distances of several centimeters. Optical absorption persists long after the decay of plasma fluorescence, indicating a slower component to plume transport. The absorption of YO formed by YBCO ablation in vacuum and by-yttrium ablation in oxygen is presented. Fast electric ion probes are utilized to measure velocities and total collected charge of the positive ions in the expanding YBCO laser plasma from near-threshold, vacuum conditions into the high fluence, background gas conditions utilized for thin-film growth. The exponential attenuation of the positive ion flux transmitted through 50--300 mTorr background …
Date: September 1, 1991
Creator: Geohegan, D.B.
System: The UNT Digital Library
Requirements for a Network Storage Service in a supercomputer environment (open access)

Requirements for a Network Storage Service in a supercomputer environment

Sandia National Laboratories has completed a requirements study for a networked mass storage system. The areas of user functionality, network connectivity, and performance were analyzed to determine specifications for a Network Storage Service to operate in supercomputer environment. 4 refs.
Date: September 26, 1991
Creator: Kelly, S.M.
System: The UNT Digital Library
Compact Fusion Advanced Rankine (CFARII) power cycle---Operating regimes (open access)

Compact Fusion Advanced Rankine (CFARII) power cycle---Operating regimes

Performance (cost/kWe and efficiency) of generic Compact Fusion Advanced Rankine (CFARII) power conversion is investigated for various working fluids, operating temperatures and pressures, and thermal power levels. A general conclusion is that good CFARII performance is found for a remarkably broad range of materials, temperatures, pressures and power levels, which gives considerable flexibility to future design studies which may apply CFARII energy conversion to specific fusion energy sources such as ICF, MICF, and Mini-PACER. 5 refs, 7 figs., 2 tabs.
Date: September 30, 1991
Creator: Logan, B. G.
System: The UNT Digital Library