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Ab initio calculations of the charge state of stopping in a finite-temperature target (open access)

Ab initio calculations of the charge state of stopping in a finite-temperature target

A calculation was made of the time dependent charge state of a heavy projectile traversing a finite-temperature target. The calculation uses an average-atom model to integrate the rate equations.
Date: March 25, 1982
Creator: Bailey, D.; Lee, Y. T. & More, R. M.
System: The UNT Digital Library
Accurate Computer Simulation of a Drift Chamber (open access)

Accurate Computer Simulation of a Drift Chamber

A general purpose program for drift chamber studies is described. First the capacitance matrix is calculated using a Green's function technique. The matrix is used in a linear-least-squares fit to choose optimal operating voltages. Next the electric field is computed, and given knowledge of gas parameters and magnetic field environment, a family of electron trajectories is determined. These are finally used to make drift distance vs time curves which may be used directly by a track reconstruction program. Results are compared with data obtained from the cylindrical chamber in the Axial Field Magnet experiment at the CERN ISR.
Date: March 25, 1980
Creator: Killian, T J
System: The UNT Digital Library
AI/Simulation Fusion Project at Lawrence Livermore National Laboratory (open access)

AI/Simulation Fusion Project at Lawrence Livermore National Laboratory

This presentation first discusses the motivation for the AI Simulation Fusion project. After discussing very briefly what expert systems are in general, what object oriented languages are in general, and some observed features of typical combat simulations, it discusses why putting together artificial intelligence and combat simulation makes sense. We then talk about the first demonstration goal for this fusion project.
Date: April 25, 1984
Creator: Erickson, S.A.
System: The UNT Digital Library
Analysis of multipass laser amplifier systems for storage laser media (open access)

Analysis of multipass laser amplifier systems for storage laser media

The performance characteristics of single pass and multipass storage laser amplifiers are presented and compared. The effects of the multipass amplifier parameters on the extraction characteristics are examined. For a wide range of conditions the multipass amplifier is found to provide high energy gain and high efficiency simultaneously. This is a significant advantage over the single pass laser amplifier. Finally, three specific storage laser amplifier systems, flashlamp pumped V:MgF/sub 2/, XeF laser pumped Tm:Glass, and photolytically pumped Selenium, are examined. The performance characteristics for each of the three systems are calculated and compared.
Date: March 25, 1980
Creator: Harvey, James F.
System: The UNT Digital Library
Angular measurements in optical testing (open access)

Angular measurements in optical testing

The measurement of angles plays an important role in practically every discipline of optics, including prism manufacture, optical assembly and alignment. It is the purpose of this paper to review some of the angle measurement techniques and how they are used in optical testing.
Date: September 25, 1980
Creator: Thomas, N.L.
System: The UNT Digital Library
Anomalies in near-threshold photoabsorption: Resonances, ''white-lines'' and other enhancements (open access)

Anomalies in near-threshold photoabsorption: Resonances, ''white-lines'' and other enhancements

Synchrotron measurements of near-threshold and broad-range (80 to 1000 eV) absolute photoabsorption cross sections were taken at Brookhaven using the plane grating monochromator at the VuV storage ring beam line U14A of the NSLS facility. Transmission data for well characterized multilayer foils of C, Ti, Cr, Ni, Cu, Th and U provided absolute cross sections with 10% overall uncertainties and better than 2 eV resolution.
Date: February 25, 1987
Creator: Del Grande, N.K.
System: The UNT Digital Library
[Article about Fred Harvey History] (open access)

[Article about Fred Harvey History]

Article written by Keith Hines about his memories and knowledge about the history of George Hill and Fred Harvey, as well as Harvey Houses and Harvey Girls.
Date: May 25, 1984
Creator: Hines, Keith
System: The Portal to Texas History
Atomic processes in matter-antimatter interactions (open access)

Atomic processes in matter-antimatter interactions

Atomic processes dominate antiproton stopping in matter at nearly all energies of interest. They significantly influence or determine the antiproton annihilation rate at all energies around or below several MeV. This article reviews what is known about these atomic processes. For stopping above about 10 eV the processes are antiproton-electron collisions, effective at medium keV through high MeV energies, and elastic collisions with atoms and adiabatic ionization of atoms, effective from medium eV through low keB energies. For annihilation above about 10 eV is the enhancement of the antiproton annihilation rate due to the antiproton-nucleus coulomb attraction, effective around and below a few tens of MeV. At about 10 eV and below, the atomic rearrangement/annihilation process determines both the stopping and annihilation rates. Although a fair amount of theoretical and some experimental work relevant to these processes exist, there are a number of energy ranges and material types for which experimental data does not exist and for which the theoretical information is not as well grounded or as accurate as desired. Additional experimental and theoretical work is required for accurate prediction of antiproton stopping and annihilation for energies and material relevant to antiproton experimentation and application.
Date: January 25, 1988
Creator: Morgan, D. L.
System: The UNT Digital Library
Build-up of tritium in a liquid-lithium breeding blanket for an inertial-confinement-fusion chamber (open access)

Build-up of tritium in a liquid-lithium breeding blanket for an inertial-confinement-fusion chamber

The build-up of tritium in a liquid lithium breeding blanket for an ICF chamber has been examined. The break-even time is found to decrease both the increasing tritium breeding ratio and increasing values of ..cap alpha.., the fraction of unburned tritium absorbed in lithium. The break-even inventory also decreased with increasing breeding ratio but increases with increasing values ..cap alpha... For a molten-salt extraction process, the steady-state tritium inventory in lithium is inversely proportional to lithium flow rate through the extraction system. The lithium flow rate through the tritium extraction system required to maintain a given tritium concentration increases with increasing values of ..cap alpha...
Date: August 25, 1981
Creator: Meier, W. R.
System: The UNT Digital Library
Cancer risks and neutron RBE's from Hiroshima and Nagasaki (open access)

Cancer risks and neutron RBE's from Hiroshima and Nagasaki

The new radiation dose estimates for Hiroshima and Nagasaki are radiobiologically examined for compatability with other human and experimental data. The new doses show certain improvements over the original T65 doses. However, they suggest for chronic granulocytic leukemia, total malignancies, and chromosome aberrations, at neutron doses of 1 rad, RBEs in excess of 100, higher than expected from other findings. This and other indications suggest that either there are unrecognized systematic problems with the various radiobiological data, or the new doses are deficient in neutrons for Hiroshima, by a factor of about five. If in fact there were actually some 5-fold more dose from neutrons at Hiroshima than estimated by the new calculations, the RBEs would agree well with laboratory results, and other inconsistencies would largely disappear. Cancer risks are estimated for neutrons from the new doses and are compared with those estimated from radiobiologically reconciled doses (the new doses adjusted by adding approximately 5-fold more neutrons). The latter appear more reasonable. For low-LET radiation, cancer risk estimates are changed very little by the new dose estimates for Nagasaki.
Date: March 25, 1982
Creator: Dobson, R.L. & Straume, T.
System: The UNT Digital Library
Commercial oxide paints as coatings for SiGe thermoelectric materials (open access)

Commercial oxide paints as coatings for SiGe thermoelectric materials

Silicon-germanium alloys are used as thermoelectric materials for radioisotope thermoelectric generators. One problem is the loss of the alloy by sublimation. In the Unicouple, sublimation was minimized by a Si/sub 3/N/sub 4/ coating. In the Multicouple design the application of Si/sub 3/N/sub 4/ coatings which is done at high temperature is not practical. Suppression of sublimation in the Multicouple design is presently accomplished by applying glass coatings. The difficulties encountered with the glass coatings are associated with the poor adherence of the coatings. In the present study, commercial oxide points (mainly ZrO/sub 2/) which have low thermal expansion coefficients are used as coating materials. No spalling from the surface of the coated sample occurred in 1506 hours at 1080/sup 0/C in vacuum, and sublimation was reduced significantly. Zirconium silicate was observed on the surface by x-ray diffraction.
Date: August 25, 1986
Creator: Amano, T.; Beaudry, B. J. & Gschneidner, K. A., Jr.
System: The UNT Digital Library
Comparison of observed and predicted Kr-85 air concentrations (open access)

Comparison of observed and predicted Kr-85 air concentrations

A computer code, ANEMOS has been written to estimate concentrations in air and ground deposition rates for Atmospheric Nuclides Emitted from Multiple Operation Sources. This code uses a modified Gaussian plum equation. Output from ANEMOS includes annual-average air concentrations and ground deposition rates of dispersed radionuclides and daughters. To use the environmental transport model properly, some estimate of the models predictive accuracy must be obtained. To validate the ANEMOS model, one year of weekly average Kr-85 concentrations observed at 13 stations located 28 to 144 km distant from continuous point source at the Savannah River Plant (SRP), Aiken, South Carolina, have been used. There was a general tendency for the model to underpredict the observed air concentrations slightly. Pearsons's correlation between pairs of logarithms of observed and predicted annual-average values was r = 0.84. The monthly results tend to show more scatter than do either the seasonal or the annual comparisons. 18 references, 3 figures, 3 tables.
Date: April 25, 1984
Creator: Yildiran, M. & Miller, C. W.
System: The UNT Digital Library
Confinement and the Pomeron (open access)

Confinement and the Pomeron

The importance of confinement for obtaining a unitary high-energy limit for QCD is discussed. Minijets'' are argued to build up non-unitary behavior{endash}when k{sub T} {gt} {Lambda} is imposed. For minijets to mix with low k{sub T} Pomeron Field Theory describing confinement, and give consistent asymptotic behavior, new quarks'' must enter the theory above the minijet transverse momentum scale. The Critical Pomeron is the resulting high-energy limit. 22 refs.
Date: September 25, 1989
Creator: White, A.R.
System: The UNT Digital Library
Construction and operation of the 12-T superconducting coils for the Mirror Fusion Test Facility (open access)

Construction and operation of the 12-T superconducting coils for the Mirror Fusion Test Facility

We have successfully constructed and tested a pair of high-field coils that is part of the magnet set of the Mirror Fusion Test Facility (MFTF-B) at the Lawrence Livermore National Laboratory. Each coil consists of a multifilamentary Nb/sub 3/Sn magnet nested inside a multifilamentary NbTi magnet. During our test, these coils produced a central field of 12 T, with a peak conductor field of 12.5 T. The dimensions of the Nb/sub 3/Sn insert coil are: 1.34-m bore, 2.57-m outer diameter, and 1.14-m overall length. These coils were designed to be fully cryogenically stabilized and cooled by pool-boiling liquid helium. The operating current density of the Nb/sub 3/Sn coils is 2000 A/cm/sup 2/ and 2400 A/cm/sup 2/ for the NbTi magnet. In this paper, we present design considerations and details, construction techniques, and operational results of these coils.
Date: September 25, 1986
Creator: Zbasnik, J. P.; Kozman, T. A.; Shimer, D. W. & Hathaway, D. R.
System: The UNT Digital Library
Cryogenic analysis of forced-cooled, superconducting TF magnets for compact tokamak reactors (open access)

Cryogenic analysis of forced-cooled, superconducting TF magnets for compact tokamak reactors

Current designs for compact tokamak reactors require the toroidal- field (TF) superconducting magnets to produce fields from 10 to 15 T at the winding pack, using high-current densities to high nuclear heat loads (greater than 1 kW/coil in some instances), which are significantly greater than the conduction and radiation heat loads for which cryogenic systems are usually designed. A cryogenic system for the TF winding pack for two such tokamak designs has been verified by performing a detailed, steady-state heat-removal analysis. Helium properties along the forced-cooled conductor flow path for a range of nuclear heat loads have been calculated. The results and implications of this analysis are presented. 12 refs., 6 figs.
Date: October 25, 1988
Creator: Kerns, J. A.; Slack, D. S. & Miller, J. R.
System: The UNT Digital Library
Dynamical Processes in Heavy Ion Reactions (open access)

Dynamical Processes in Heavy Ion Reactions

In this report I review the physical assumptions of the Boltzmann Master Equation (BME). Comparisons of the model with experimental neutron spectra gated on evaporation residues for a range of incident projectile energies and masses are presented; next, I compare n spectra gated on projectile-like fragments, followed by comparisons with ungated, inclusive proton spectra. I will then consider secondary effects from the nucleon-nucleon processes involved in the heavy ion relaxation processes, specifically the high energy ..gamma..-rays which have been observed at energies up to 140 MeV in collisions of heavy ions of 20/endash/84 MeV/..mu... Another secondary effect, subthreshold pion production, was covered in the XVII School and will not be repeated. 39 refs., 16 figs.
Date: July 25, 1988
Creator: Blann, M. & Remington, B. A.
System: The UNT Digital Library
Electron-Impact Ionization Data for the Fe Isonuclear Sequence (open access)

Electron-Impact Ionization Data for the Fe Isonuclear Sequence

Atomic data for the electron-impact ionization of ions in the Fe isonuclear sequence is reviewed. The best available data are identified. Comments are made on current research activities leading to future data for Fe ions. 23 refs., 29 figs., 12 tabs.
Date: November 25, 1986
Creator: Pindzola, M. S.; Griffin, D. C.; Bottcher, C.; Younger, S. M. & Hunter, H. T.
System: The UNT Digital Library
Engineering design of the Nova Laser Facility for inertial-confinement fusion (open access)

Engineering design of the Nova Laser Facility for inertial-confinement fusion

The design of the Nova Laser Facility for inertial confinement fusion experiments at Lawrence Livermore National Laboratory is presented from an engineering perspective. Emphasis is placed upon design-to-performance requirements as they impact the various subsystems that comprise this complex experimental facility.
Date: January 25, 1982
Creator: Simmons, W. W.; Godwin, R. O.; Hurley, C. A.; Wallerstein, E. P.; Whitham, K.; Murray, J. E. et al.
System: The UNT Digital Library
Enhancing the performance of a high-gain free electron laser operating at millimeter wavelengths (open access)

Enhancing the performance of a high-gain free electron laser operating at millimeter wavelengths

A high-gain, high extraction efficiency, free electron laser (FEL) amplifier operating at the Experimental Test Accelerator (ETA) at 34.6 GHz has demonstrated a small signal gain of 13.4 dB/m. With a 30 kW input signal, the amplifier has produced a saturated output of 80 MW and a 5% extraction efficiency. Comparison of these results with a linear model at small signal levels indicates that the amplifier can deliver saturated output starting from noise, if the brightness of the electron beam is sufficiently high. The brightness of the ETA is far below that possible with optimized choice of practical design characteristics such as peak voltage, cathode type, gun electrode geometry, and focusing field topology. In particular, the measured brightness of the ETA injector is limited by plasma effects from the present cold, plasma cathode. As part of a coordinated theoretical and experimental effort to improve injector performance, we are using the EBQ gun design code to explore the current limits of gridless, relativistic, Pierce columns with moderate current density (>50 A/cm/sup 2/) at the cathode. The chief component in our experimental effort is a readily modified electron gun that will allow us to test many candidate cathode materials, types, and electrode …
Date: October 25, 1984
Creator: Barletta, W. A.; Anderson, B.; Fawley, W. M.; Neil, V. K.; Orzechowski, T. J.; Prosnitz, D. et al.
System: The UNT Digital Library
An experiment to measure the electron neutrino mass using a cryogenic tritium source (open access)

An experiment to measure the electron neutrino mass using a cryogenic tritium source

An experiment has been performed to determine the electron neutrino mass with the precision of a few eV by measuring the tritium beta decay energy distribution near the endpoint. Key features of the experiment are a 2 eV resolution electrostatic spectrometer and a high-activity frozen tritium source. It is important that the source have electronic wavefunctions which can be accurately calculated. These calculations have been made for tritium and the HeT/sup +/ daughter ion and allow determination of branching fractions to 0.1% and energy of the excited states to 0.1 eV. The excited final molecular state calculations and the experimental apparatus are discussed. 4 refs., 5 figs.
Date: June 25, 1985
Creator: Fackler, O.; Jeziorski, B.; Kolos, W.; Monkhorst, H.; Mugge, M.; Sticker, H. et al.
System: The UNT Digital Library
The Fermilab upgrade (open access)

The Fermilab upgrade

This paper discusses the upgrades needed at Fermilab Tevatron facility to meet the future physics needs. Historical aspects are also discussed. 3 figs.
Date: September 25, 1988
Creator: Lederman, L.M.
System: The UNT Digital Library
Fokker-Planck calculations of electron cyclotron resonant heating (ECRH) in mirror geometry (open access)

Fokker-Planck calculations of electron cyclotron resonant heating (ECRH) in mirror geometry

A time dependent, bounce-averaged Fokker-Planck code, with quasi-linear diffusion at fundamental and second harmonic frequencies, has been used to study cold plasma trapping and heating of hot electrons in mirror geometry. Both electron-electron and electron-ion Coulomb collisions are included. The code can model either cavity heating (electric field throughout cavity as in EBT) or beam controlled heating (electric field spatially restricted as in the TMX-Upgrade tandem mirror). The heating method has implications for the equilibrium energy and anisotropy of the hot electrons. In TMX-Upgrade, off-midplane heating at the second harmonic in the thermal barrier is planned as a means to control anisotropy (T/sub parallel//T/sub perpendicular/. By spatially limiting (limit in B) the microwave beam and with strong single-pass absorption, the mean hot electron energy may also be controlled since the heating rate decreases at high energy due to the relativistic mass shift of the resonance to higher magnetic field.
Date: November 25, 1981
Creator: Stallard, B. W.; Matsuda, Y. & Nevins, W. M.
System: The UNT Digital Library
Galaxies and Saturn's rings: Gravitational analogues of nonneutral plasmas (open access)

Galaxies and Saturn's rings: Gravitational analogues of nonneutral plasmas

Orbit and collective dynamics in disk galaxies and in Saturn's rings are gravitational analogues of those occurring in nonneutral plasmas. The interesting problems for such ''gravitational plasmas'' are analogous to single-disk studies of transverse dynamics in particle beams. Of particular interest are various orbit-resonances with spiral density and bending waves in these disks which are analogous to electrostatic waves in nonneutral beam plasmas. The background physics, terminology and results of astrophysical investigations in these fields are surveyed in this paper. 53 refs., 19 figs., 1 tab.
Date: April 25, 1985
Creator: Mark, J.W.K.
System: The UNT Digital Library
Geothermal Direct Heat Applications Program Summary (open access)

Geothermal Direct Heat Applications Program Summary

Because of the undefined risk in the development and use of geothermal energy as a thermal energy source, the Department of Energy Division of Geothermal Energy solicited competitive proposals for field experiments in the direct use of geothermal energy. Twenty-two proposals were selected for cost-shared funding with one additional project co-funded by the State of New Mexico. As expected, the critical parameter was developing a viable resource. So far, of the twenty resources drilled, fourteen have proved to be useful resources. These are: Boise, Idaho; Elko heating Company in Nevada; Pagosa Springs, Colorado; Philip School, Philip, South Dakota; St. Mary's Hospital, Pierre, South Dakota; Utah Roses near Salt Lake City; Utah State Prison, Utah; Warm Springs State Hospital, Montana; T-H-S Hospital, Marlin, Texas; Aquafarms International in the Cochella Valley, California; Klamath County YMCA and Klamath Falls in Oregon; Susanville, California and Monroe, utah. Monroe's 164 F and 600 gpm peak flow was inadequate for the planned project, but is expected to be used in a private development. Three wells encountered a resource insufficient for an economical project. These were Madison County at Rexburg, Idaho; Ore-Ida Foods at Ontario, Oregon and Holly Sugar at Brawley, California. Three projects have yet to …
Date: September 25, 1981
Creator: unknown
System: The UNT Digital Library