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Non-equilibrium dynamics in finite-temperature QCD (open access)

Non-equilibrium dynamics in finite-temperature QCD

An overview on the status of kinetic theory approaches to non-equilibrium dynamics in finite temperature QCD is given, and results and difficulties in determining the transport properties and equilibration time scales for a quark gluon plasma produced in nuclear collisions are discussed. 15 refs.
Date: November 1, 1988
Creator: Heinz, U.
System: The UNT Digital Library
History of the application of the generalized Lewis acid-base theory to metals (open access)

History of the application of the generalized Lewis acid-base theory to metals

The history of my experiences with intermetallics has been found useful by students seeking my advice on which directions in science they should be emphasizing. In response to their question, I point to a mobile in my office consisting of seven hands pointing in different directions. Science comes up with so many unexpected developments that one's education should have a broad enough base to allow one to branch out in any direction to take advantage of unexpected opportunities. My historical presentation will be a personal account that I hope will serve as a guide to students. There have been many unexpected abrupt changes in my research.
Date: November 1, 1988
Creator: Brewer, L.
System: The UNT Digital Library
Effect of lepton energy resolution on Higgs searches at the SSC (open access)

Effect of lepton energy resolution on Higgs searches at the SSC

We discuss the effects of realistic detector resolutions on the processes H ..-->.. ZZ ..-->.. e/sup +/e/sup /minus//e/sup +/e/sup /minus// and H ..-->.. ZZ ..-->.. e/sup +/e/sup minus/..mu../sup +/..mu../sup /minus// at the SSC. The background from Zt/bar t/ where the t/bar t/ system produces two isolated leptons in its decays is discussed. 10 refs., 6 figs., 2 tabs.
Date: November 1, 1988
Creator: Hinchliffe, I. & Wang, E.M.
System: The UNT Digital Library
Proceedings of the second users meeting for the Advanced Photon Source (open access)

Proceedings of the second users meeting for the Advanced Photon Source

The second national users meeting for the Advanced Photon Source (APS) at Argonne National Laboratory -- held March 9--10, 1988, at Argonne -- brought scientists and engineers from industry, universities, and national laboratories together to review the status of the facility and expectations for its use. Presented papers and status reports in these proceedings include the current status of the APS with respect to accelerator systems, experimental facilities, and conventional facilities; scientific papers on frontiers in synchrotron applications summaries of reports on workshops held by users in certain topical groups; reports in research and development activities in support of the APS at other synchrotron facilities; and noted from a discussion of APS user access policy. In addition, actions taken by the APS Users Organization and its Executive Committee are documented in this report.
Date: November 1, 1988
Creator: unknown
System: The UNT Digital Library
Proceedings of the Chinese-American symposium on energy markets and the future of energy demand (open access)

Proceedings of the Chinese-American symposium on energy markets and the future of energy demand

The Symposium was organized by the Energy Research Institute of the State Economic Commission of China, and the Lawrence Berkeley Laboratory and Johns Hopkins University from the United States. It was held at the Johns Hopkins University Nanjing Center in late June 1988. It was attended by about 15 Chinese and an equal number of US experts on various topics related to energy demand and supply. Each presenter is one of the best observers of the energy situation in their field. A Chinese and US speaker presented papers on each topic. In all, about 30 papers were presented over a period of two and one half days. Each paper was translated into English and Chinese. The Chinese papers provide an excellent overview of the emerging energy demand and supply situation in China and the obstacles the Chinese planners face in managing the expected increase in demand for energy. These are matched by papers that discuss the energy situation in the US and worldwide, and the implications of the changes in the world energy situation on both countries. The papers in Part 1 provide historical background and discuss future directions. The papers in Part 2 focus on the historical development of …
Date: November 1, 1988
Creator: Meyers, S. (ed.)
System: The UNT Digital Library
On the survivability of diagnostic windows in the CIT (Compact Ignition Tokamak) reactor (open access)

On the survivability of diagnostic windows in the CIT (Compact Ignition Tokamak) reactor

The problem of radiation induced stresses in CIT diagnostic windows is discussed. Existing data indicate windows of existing design will probably survive if placed on the periphery of the reactor. There is a lack of adequate engineering data upon which the design and survivability of windows can be based. 22 refs., 5 figs., 2 tabs.
Date: November 1, 1988
Creator: Taylor, A.
System: The UNT Digital Library
Proceedings of the DOE/Industry Sensor Working Group meeting, Austin, Texas (open access)

Proceedings of the DOE/Industry Sensor Working Group meeting, Austin, Texas

This paper report contains topics presented at a sensor workshop group meeting. The topics describe measuring instruments of use in the pulp and paper industry. Topics include: measurement of solids fraction; process instrumentation research for the pulp paper industry; real-time non-contact optical surface motion monitor; on-machine sensors to measure paper mechanical properties; hierarchical intelligent control of industrial processes -- an in-parallel lime kiln application; proposal for research on lignin concentration measurement in pulping liquors; and advanced polymeric sensor materials for industrial drying.
Date: November 1, 1988
Creator: unknown
System: The UNT Digital Library
Hadronic energy spectra from nuclear collisions: Effects from collective transverse flow and the phase transition to quark matter (open access)

Hadronic energy spectra from nuclear collisions: Effects from collective transverse flow and the phase transition to quark matter

I give an overview of the processes determining the shape of energy spectra of hadrons emitted in relativistic nuclear collisions, and discuss how one can extract from them information on the presence of collective transverse flow and on the transition to quark-gluon matter in such collisions. 6 refs., 3 figs.
Date: November 1, 1988
Creator: Heinz, U.
System: The UNT Digital Library
Computer simulation of mixed classical-quantum systems (open access)

Computer simulation of mixed classical-quantum systems

We briefly review three important methods that are currently used in the simulation of mixed systems. Two of these techniques, path integral Monte Carlo or molecular dynamics and dynamical simulated annealing, have the limitation that they can only describe the structural properties in the ground state. The third so-called quantum molecular dynamics (QMD) method can provide not only the static properties but also the real-time dynamics of a quantum particle at finite temperatures. 10 refs.
Date: November 1, 1988
Creator: Kalia, R.K. & Vashishta, P.
System: The UNT Digital Library
Review of J//psi/ decays (open access)

Review of J//psi/ decays

Recent results from the Mark III collaboration in radiative J//psi/ decays are presented. This includes a study of iota/E decays in J//psi/ el/eta/ and elelp, two pseudoscalar decays near threshold in J//psi/ el and el /bar K/K and two vector decays in J//psi/ el /bar K//sup o/*K/sup o/*. 20 refs., 9 figs.
Date: November 1, 1988
Creator: Toki, W.H.
System: The UNT Digital Library
Final focus supports for a TeV Linear Collider (open access)

Final focus supports for a TeV Linear Collider

Final focus quadrupoles supported from structures in the endcap region of a physics experiment appear to meet the high-frequency vibration and stability criteria for a TeV Linear Collider (TLC). The support stays within a ten-degree cone, minimizing interference with the experimental apparatus. 3 refs., 3 figs.
Date: November 1, 1988
Creator: Ash, W.W.
System: The UNT Digital Library
IEEE P1596, a scalable coherent interface for GigaByte/sec multiprocessor applications (open access)

IEEE P1596, a scalable coherent interface for GigaByte/sec multiprocessor applications

IEEE P1596, the Scalable Coherent Interface (formerly known as SuperBus) is based on experience gained during the development of Fastbus (IEEE 960), Futurebus (IEEE 896.1) and other modern 32-bit buses. SCI goals include a minimum bandwidth of 1 GByte/sec per processor; efficient support of a coherent distributed-cache image of shared memory; and support for segmentation, bus repeaters and general switched interconnections like Banyan, Omega, or full crossbar networks. To achieve these ambitious goals, SCI must sacrifice the immediate handshake characteristic of the present generation of buses in favor of a packet-like split-cycle protocol. Wire-ORs, broadcasts, and even ordinary passive bus structures are to be avoided. However, a lower performance (1 GByte/sec per backplane instead of per processor) implementation using a register insertion ring architecture on a passive ''backplane'' appears to be possible using the same interface as for the more costly switch networks. This paper presents a summary of current directions, and reports the status of the work in progress.
Date: November 1, 1988
Creator: Gustavson, D.B.
System: The UNT Digital Library
Rare decays of charmed D mesons (open access)

Rare decays of charmed D mesons

We summarize the results of searches for rare decays of the charmed D mesons, based on a data sample of 9.4 pb/sup /minus//1//, collected with the MarkIII detector at ..sqrt..S = 3.77 GeV at the e/sup +/e/sup /minus// storage ring SPEAR. We searched for flavour-changing weak neutral currents and for leptons family number violation in the D/degree/-decay modes D/degree/ ..-->.. ..mu..e, D/degree/ ..-->.. e/sup +/e/sup /minus// and D/degree/ ..-->.. K/degree/ e/sup +/e/sup /minus//. No candidates were observed at a sensitivity to the branching ratios at the 10/sup /minus//4// level. Since couplings of many new intermediate particles in models beyond the Standard Model are expected to be flavour-dependent, these searches in the charmed sector are complementary to the ones performed with leptons and with K- or B-mesons. 9 refs., 3 figs.
Date: November 1, 1988
Creator: Grab, C.
System: The UNT Digital Library
Deuterium pumping speed measurements on 77 K cryopanels and implications for D-T retention in neutral beam systems (open access)

Deuterium pumping speed measurements on 77 K cryopanels and implications for D-T retention in neutral beam systems

An upper limit for the pumping speed of deuterium on 77 K surfaces has been determined by in-situ pressure measurements in a TFTR neutral beam line pumped by 423 m/sup 2/ of LN/sub 2/-cooled cryopanels. The measurement has importance for estimating the tritium retention in the beam line following operation of the ion sources with tritium. No D/sub 2/ pumping was observed. An upper limit for D/sub 2/ pumping on 77 K surfaces of less than or equal to2.4 x 10/sup -7/ l/s cm/sup 2/ was determined, corresponding to a D/sub 2/ sticking coefficient of less than or equal to1.5 x 10/sup -8/. Based on the upper limit a D-T retention factor, equal to the ratio of retained D-T to D-T input, has been determined to be less than or equal to5 x 10/sup -3/. This upper limit for D-T retention bounds the tritium inventory within the beam line to a small fraction of the tritium throughput. Comparably small upper limits for hydrogenic sticking coefficients, of the order of 10/sup -6/ - 10/sup -10/, have been determined from a review of H/sub 2/O cryotrapping measurements at 77 K and from the physical adsorption studies of H/sub 2/ on H/sub 2/O …
Date: November 1, 1988
Creator: Dylla, H.F.
System: The UNT Digital Library
Theoretical implications of the W-Z mass difference and the capabilities of the D0 detector in measuring it (open access)

Theoretical implications of the W-Z mass difference and the capabilities of the D0 detector in measuring it

We examine the phenomenology of the W-Z mass difference as a function of the top quark mass and the Higgs mass. A detailed analysis is presented on how well the mass difference is measurable using the D0 detector at Fermilab. We show that the effective mass distribution of the Z/sup 0/ is not a Breit-Wigner at the Tevatron and present techniques developed for the D0 detector simulation that can be used to reduce the systematic errors in measuring the W-Z mass difference. Scenarios are presented for the integrated luminosities of 10 pb/sup -1/ and 100 pb/sup -1/ at the Tevatron. It is shown that the Tevatron is competitive with LEP II for integrated luminosities of 100 pb/sup -1/ in attainable precisions in this measurement. These considerations argue strongly for the pp option in the Tevatron upgrade program. 17 refs., 14 figs., 2 tabs.
Date: November 1, 1988
Creator: Raja, R.
System: The UNT Digital Library
Preliminary results from ASP on tests of QED to order. cap alpha. /sup 4/ in e/sup +/e/sup -/ annihilation at. sqrt. s = 29 GeV (open access)

Preliminary results from ASP on tests of QED to order. cap alpha. /sup 4/ in e/sup +/e/sup -/ annihilation at. sqrt. s = 29 GeV

Tests of QED to order ..cap alpha../sup 4/ performed with the ASP detector at PEP are presented. Measurements have been made of exclusive e/sup +/e/sup -/e/sup +/e/sup -/, e/sup +/e/sup -/..gamma gamma.. and ..gamma gamma gamma gamma.. final states with all particles above 50 milliradians with respect to the e/sup +/e/sup -/ beam line. These measurements represent a significant increase in statistics over previous measurements. All measurements agree well with theoretical predictions. 5 refs., 1 tab.
Date: November 1, 1988
Creator: Hawkins, C.A.
System: The UNT Digital Library
Compensation for crystal penetration in high resolution positron tomography (open access)

Compensation for crystal penetration in high resolution positron tomography

We have characterized the effects of crystal penetration by annihilation photons in circular ring positron tomographs. They are most serious in high resolution instruments having small detectors. When annihilation photons are not normally incident and penetrate some distance into the scintillator before interacting, the measurement of their transverse position becomes uncertain. This penetration of photons into the detector material before interaction is a statistical process which leads to significant displacement and anisotropy of the point spread function. The subject of this work is mathematical correction of emission datasets by performing a two-dimensional spatially variant deconvolution of the emission data in sinogram format. Examples for the Donner 600-Crystal Positron Tomograph are presented, and the amplification of statistical errors resulting from the correction procedure is also discussed. 7 refs., 9 figs., 2 tabs.
Date: November 1, 1988
Creator: Huesman, R.H.; Salmeron, E.M. & Baker, J.R.
System: The UNT Digital Library
Fast Flux Test Facility interim examination and maintenance cell contaminated sodium recovery system: Remote handling design consideration (open access)

Fast Flux Test Facility interim examination and maintenance cell contaminated sodium recovery system: Remote handling design consideration

The Westinghouse Hanford Company is installing a remotely operated Contaminated Sodium Recovery System (CSRS) at the Fast Flux Test Facility (FFTF) located in Richland, Washington. The CSRS will recover activated sodium that accumulates in fuel transfer machines during core component transfer operations. Drip pots from the FFTF fuel handling machines will be delivered to the shielded, argon-inerted Interim Examination and Maintenance (IEM) Cell, a hot cell located in the FFTF containment structure. Installation of the CSRS replaces a previously manual operation that required disposal of radioactive sodium with a completely remote operation that will return sodium to service in the plant. The CSRS will minimize the accumulation of hazardous waste and reduce personnel exposure to radioactive materials. Equipment for the CSRS is currently being fabricated and tested before installation in the IEM Cell. 6 figs.
Date: November 1, 1988
Creator: Carteret, B. A.
System: The UNT Digital Library
Crossbar switch backplane and its application (open access)

Crossbar switch backplane and its application

A crossbar switch backplane design (Bus Switch Backplane) based on TI's crossbar switch chip is described. This backplane holds a maximum of 16 modules and allows simultaneous communications between up to 8 pairs of modules. The aggregate data transfer rate on the backplane is 160 Mbyte/sec. The Bus Switch Backplane is an essential part of the ACP Multi Array Processor, a supercomputer for site oriented problems. The first application of this machine is in Lattice Gauge Theory calculations. The Bus Switch Backplane also finds ready application in data acquisition schemes based on the ACP multi-microprocessor system. 4 refs., 8 figs.
Date: November 1, 1988
Creator: Atac, R.; Cook, A.; Deepe, J.; Fischler, M.; Gaines, I.; Husby, D. et al.
System: The UNT Digital Library
The development of a Compton lung densitometer (open access)

The development of a Compton lung densitometer

A field instrument is being developed for the non-invasive determination of absolute lung density using unique Compton backscattering techniques. A system consisting of a monoenergetic gamma-ray beam and a shielded high resolution high-purity-germanium (HPGe) detector in a close-coupled geometry is designed to minimize errors due to multiple scattering and uncontrollable attenuation in the chestwall. Results of studies on system performance with phantoms, the optimization of detectors, and the fabrication of a practical gamma-ray source are presented. 3 refs., 6 figs., 2 tabs.
Date: November 1, 1988
Creator: Loo, B. W.; Goulding, F. S.; Madden, N. W. & Simon, D. S.
System: The UNT Digital Library
A variable temperature cryostat that produces in situ clean-up germanium detector surfaces (open access)

A variable temperature cryostat that produces in situ clean-up germanium detector surfaces

Variable temperature cryostats that can maintain germanium detectors at temperatures from 82 K to about 400 K while the thermal shield surrounding the detectors remains much colder when the detectors are warmed have been developed. Cryostats such as these offer the possibility of cryopumping material from the surface of detectors to the colder thermal shield. The diode characteristics of several detectors have shown very significant improvement following thermal cycles up to about 150 K in these cryostats. Important applications for cryostats having this attribute are many. 4 figs.
Date: November 1, 1988
Creator: Pehl, R. H.; Madden, N. W.; Malone, D. F.; Cork, C. P.; Landis, D. A.; Xing, J. S. et al.
System: The UNT Digital Library
Heavy Quark Production at Collider Energies (open access)

Heavy Quark Production at Collider Energies

The theory of heavy quark production in QCD at collider energies is reviewed. The most important features of the recently published results on higher order corrections to the heavy quark production cross-section are described. The phenomenological consequences of these formulae for bottom and top quark production at Sp/bar p/S and Tevatron energies are presented. 22 refs., 13 figs., 1 tab.
Date: November 1, 1988
Creator: Ellis, R. K.
System: The UNT Digital Library
Cerium fluoride, a new fast, heavy scintillator (open access)

Cerium fluoride, a new fast, heavy scintillator

We describe the scintillation properties of Cerium Fluoride (CeF/sub 3/), a newly discovered, heavy (6.16 g/cm/sup 3/), inorganic scintillator. Its fluorescence decay lifetime, measured with the delayed coincidence method, is described by a single exponential with a 27 /+-/ ns time constant. The emission spectrum peaks at a wavelength of 340 nm, and drops to less than 10% of its peak value at 315 nm and 460 nm. When a 1 cm optical quality cube of CeF/sub 3/ is excited with 511 keV photons, a photopeak with a 20% full width at half maximum is observed at approximately half the light output of a Bismuth Germanate (BGO) crystal with similar geometry. We also present measurements of the decay time and light output of CeF/sub 3/ doped with three rare-earth elements (Dy, Er, and Pr). The short fluorescence lifetime, high density, and reasonable light output of this new scintillator suggest that it would be useful for applications where high counting rates, good stopping power, and nanosecond timing are important, such as medical imaging and nuclear science. 5 refs., 6 figs., 1 tab.
Date: November 1, 1988
Creator: Moses, W. W. & Derenzo, S. E.
System: The UNT Digital Library
Liquid gallium cooling of silicon crystals in high intensity photon beam (open access)

Liquid gallium cooling of silicon crystals in high intensity photon beam

The high-brilliance, insertion-device-based, photon beams of the next generation of synchrotron sources will deliver large thermal loads (1 kW to 10 kW) to the first optical elements. Considering the problems that present synchrotron users are experiencing with beams from recently installed insertion devices, new and improved methods of cooling these first optical elements, particularly when they are diffraction crystals, are clearly needed. A series of finite element calculations were performed to test the efficiency of new cooling geometries and new cooling fluids. The best results were obtained with liquid Ga metal flowing in channels just below the surface of the crystal. Ga was selected because of its good thermal conductivity and thermal capacity, low melting point, high boiling point, low kinetic viscosity, and very low vapor pressure. Its very low vapor pressure, even at elevated temperatures, makes it especially attractive in uhv conditions. A series of experiments were conducted at CHESS in February of 1988 that compared liquid gallium cooled silicon diffraction crystals with water cooled crystals. 2 refs., 16 figs., 1 tab.
Date: November 1, 1988
Creator: Smither, R. K.; Forster, G. A.; Bilderback, D. H.; Bedzyk, M.; Finkelstein, K.; Henderson, C. et al.
System: The UNT Digital Library