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Report of the Working Group on Media Accelerators (open access)

Report of the Working Group on Media Accelerators

A summary is given of the activities of those in the Media Accelerator Group. Attention was focused on the Inverse Cherenkov Accelerator, the Laser Focus Accelerator, and the Beat Wave Accelerator. For each of these the ultimate capability of the concept was examined as well as the next series of experiments which needs to be performed in order to advance the concept.
Date: April 12, 1982
Creator: Sessler, Andrew M.
System: The UNT Digital Library
Lawrence Livermore National Laboratory laser-fusion program (open access)

Lawrence Livermore National Laboratory laser-fusion program

The goals of the Laser-Fusion Program at Lawrence Livermore National Laboratory are to produce well-diagnosed, high-gain, laser-driven fusion explosions in the laboratory and to exploit this capability for both military applications and for civilian energy production. In the past year we have made significant progress both theoretically and experimentally in our understanding of the laser interaction with both directly coupled and radiation-driven implosion targets and their implosion dynamics. We have made significant developments in fabricating the target structures. Data from the target experiments are producing important near-term physics results. We have also continued to develop attractive reactor concepts which illustrate ICF's potential as an energy producer.
Date: July 12, 1982
Creator: Ahlstrom, H.G.
System: The UNT Digital Library
Target plane imaging system for the Nova laser (open access)

Target plane imaging system for the Nova laser

The Nova laser, in operation since December 1984, is capable of irradiating targets with light at 1.05 ..mu..m, 0.53 ..mu..m, and 0.35 ..mu..m. Correct alignment of these harmonic beams uses a system called a target plane imager (TPI). It is a large microscope (four meters long, weighing one thousand kilograms) that relays images from the target chamber center to a video optics module located on the outside of the chamber. Several modes of operation are possible including: near-field viewing and far-field viewing at three magnifications and three wavelengths. In addition, the entire instrument can be scanned in X,Y,Z to examine various planes near chamber center. Performance of this system and its computer controls will be described.
Date: December 12, 1985
Creator: Swift, C. D.; Bliss, E. S.; Jones, W. A.; Reeves, R. J.; Seppala, L. G.; Shelton, R. T. et al.
System: The UNT Digital Library
Novel, convenient, and nonpersistent radiotracer for environmental and energy applications (open access)

Novel, convenient, and nonpersistent radiotracer for environmental and energy applications

A newly-available radioisotopic system, /sup 172/Hf-/sup 172/Lu, has excellent potential for tracer applications in which nuclear data acquisition must be accomplished in real time. The 6.7-day half-life of /sup 172/Lu is sufficient for a large fraction of tracer experiments, and should allow the direct incorporation of /sup 172/Lu into tests that have traditionally utilized much longer-lived radionuclides. Since /sup 172/Lu is the daughter component of a radioisotope generator, however, its effective shelf-life is determined by the half-life of its 1.9-year /sup 172/Hf parent. Consequently, the frequency of isotope procurement need not be any more extensive than investigators would normally be accustomed to. Discussion relevant to isotope production, generator operation, and nuclide acquisition is presented in this paper.
Date: March 12, 1984
Creator: Grant, P.M.
System: The UNT Digital Library
Determination of the beta energy (E/sub max/) using thin window instruments (open access)

Determination of the beta energy (E/sub max/) using thin window instruments

The use of simple survey instruments for beta-energy analysis is complicated by large differences that exist in the beta spectra shapes. These spectral shapes are often complex and change continuously as the betas are absorbed in air. Changes are also caused by absorbing material between the source and the detector. One may frequently encounter a combination of beta energies, either from multiple emissions from a single isotope or from several isotopes in the sample being evaluated. There may also be monoenergetic conversion electrons present in the sample or low-energy X rays which are absorbed in a similar fashion to betas. Obviously, a complete analysis of compelx beta spectra cannot be performed using only survey instruments. We present two methods which will give the approximate E/sub max/ of the beta energy responsible for the most significant portion of the beta dose. Either technique should give adequate information about the beta spectra to provide necessary guidance for the health physics evaluation of the exposure.
Date: August 12, 1983
Creator: Hankins, D.E.
System: The UNT Digital Library
Radiological design criteria for fusion power test facilities (open access)

Radiological design criteria for fusion power test facilities

The quest for fusion power and understanding of plasma physics has resulted in planning, design, and construction of several major fusion power test facilities, based largely on magnetic and inertial confinement concepts. We have considered radiological design aspects of the Joint European Torus (JET), Livermore Mirror and Inertial Fusion projects, and Princeton Tokamak. Our analyses on radiological design criteria cover acceptable exposure levels at the site boundary, man-rem doses for plant personnel and population at large, based upon experience gained for the fission reactors, and on considerations of cost-benefit analyses.
Date: February 12, 1982
Creator: Singh, M.S. & Campbell, G.W.
System: The UNT Digital Library
Test problems in radiative transfer calculations (open access)

Test problems in radiative transfer calculations

Several test problems are presented for evaluating the radiation diffusion equations. For spatial transport schemes, 1-D problems with known analytic solutions are tested on 2-D domains with non-orthogonal meshes. It is shown that a scheme based on the Finite Element Method is insensitive to grid distortions when the diffusion term is dominant. Other test problems deal with Compton scattering, specifically the 1-D Fokker-Planck equation coupled to an equation describing the change in electron temperature. The test problems model the evolution of a Planckian radiation field as it equilibrates with the electrons. In all cases, the numerical results are compared with the analytic ones. 15 refs., 9 figs., 7 tabs.
Date: January 12, 1989
Creator: Shestakov, A. I.; Kershaw, D. S. & Zimmerman, G. B.
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
Condensed Matter at High Shock Pressures (open access)

Condensed Matter at High Shock Pressures

Experimental techniques are described for shock waves in liquids: Hugoniot equation-of-state, shock temperature and emission spectroscopy, electrical conductivity, and Raman spectroscopy. Experimental data are reviewed and presented in terms of phenomena that occur at high densities and temperatures in shocked He, Ar, N/sub 2/, CO, SiO/sub 2/-aerogel, H/sub 2/O, and C/sub 6/H/sub 6/. The superconducting properties of Nb metal shocked to 100 GPa (1 Mbar) and recovered intact are discussed in terms of prospects for synthesizing novel, metastable materials. Ultrahigh pressure data for Cu is reviewed in the range 0.3 to 6TPa (3 to 60 Mbar). 56 refs., 9 figs., 1 tab.
Date: July 12, 1985
Creator: Nellis, W. J.; Holmes, N. C.; Mitchell, A. C.; Radousky, H. B. & Hamilton, D.
System: The UNT Digital Library
Large aperture optical switching devices (open access)

Large aperture optical switching devices

We have developed a new approach to constructing large aperture optical switches for next generation inertial confinement fusion lasers. A transparent plasma electrode formed in low pressure ionized gas acts as a conductive coating to allow the uniform charging of the optical faces of an electro-optic material. In this manner large electric fields can be applied longitudinally to large aperture, high aspect ratio Pockels cells. We propose a four-electrode geometry to create the necessary high conductivity plasma sheets, and have demonstrated fast (less than 10 nsec) switching in a 5x5 cm aperture KD*P Pockels cell with such a design. Detaid modelling of Pockels cell performance with plasma electrodes has been carried out for 15 and 30 cm aperture designs.
Date: December 12, 1983
Creator: Goldhar, J. & Henesian, M.A.
System: The UNT Digital Library
Conservative Differencing of the Electron Fokker-Planck Transport Equation (open access)

Conservative Differencing of the Electron Fokker-Planck Transport Equation

We need to extend the applicability and improve the accuracy of kinetic electron transport codes. In this paper, special attention is given to modelling of e-e collisions, including the dominant contributions arising from anisotropy. The electric field and spatial gradient terms are also considered. I construct finite-difference analogues to the Fokker-Planck integral-differential collision operator, which conserve the particle number, momentum and energy integrals (sums) regardless of the coarseness of the velocity zoning. Such properties are usually desirable, but are especially useful, for example, when there are spatial regions and/or time intervals in which the plasma is cool, so that the collision operator acts rapidly and the velocity distribution is poorly resolved, yet it is crucial that gross conservation properties be respected in hydro-transport applications, such as in the LASNEX code. Some points are raised concerning spatial differencing and time integration.
Date: January 12, 1981
Creator: Langdon, A. B.
System: The UNT Digital Library
Foreign Students Fueled 2% Rise in 1985 Graduate Science and Engineering Enrollment (open access)

Foreign Students Fueled 2% Rise in 1985 Graduate Science and Engineering Enrollment

Article from the National Science Foundation, noting that the 2% rise in 1985 graduate science and engineering enrollment was due to foreign students.
Date: June 12, 1987
Creator: National Science Foundation
System: The UNT Digital Library
Heterodyne phase shift diagnostic for measuring atomic vapor density (open access)

Heterodyne phase shift diagnostic for measuring atomic vapor density

We describe a technique for atomic density measurements. We generate and recombine frequency shifted laser beams producing beat signals on reference and signal detectors. Opacity in the signal detector leg is proportional to the phase difference between detector signals. 4 refs., 2 figs.
Date: November 12, 1987
Creator: Crane, J. K.; Paisner, J. A.; Johnson, M. A.; Story, T. W.; Barclay, C.; George, J. D. et al.
System: The UNT Digital Library
Vacuum measurements on the Tandem Mirror Experiment Upgrade (TMX-U) fusion experiment (open access)

Vacuum measurements on the Tandem Mirror Experiment Upgrade (TMX-U) fusion experiment

The gas inventory of the Tandem Mirror Experiment Upgrade (TMX-U) must be carefully controlled, if it is to successfully create various plasma configurations for thermal-barrier experiments designed to provide an improved performance for tandem-mirror experiments. This paper is a progress report on the calibration methods and pressure measurements of machine conditions deriving from recently improved neutral-beam gas control, and changes to the internal baffling geometry and the gettering system.
Date: August 12, 1983
Creator: Calderon, M. O.; Hunt, A. L.; Lang, D. D.; Nexsen, W. E.; Pickles, W. L. & Turner, W. C.
System: The UNT Digital Library
X-ray backlighting sources of 4 to 10 keV for laser-fusion targets (open access)

X-ray backlighting sources of 4 to 10 keV for laser-fusion targets

High-intensity, short-duration x-ray pulses are necessary to diagnose the compression of laser film targets. Present target designs are such that backlighting sources ranging from a few thousand electron volts to 100 keV will be necessary. The desired source durations range from a few tens of picoseconds for flash radiography to several nanoseconds for streaked backlighting, and the source occurrence must be tightly synchronized to that of the target-irradiating laser pulse. For the latter reason, a laser-induced x-ray pulse is preferred. An initial study of the K lines of Ti, Ni, and Zn as possible backlighting sources was conducted. The conversion efficiency of laser light into line radiation was obtained as a function of laser intensity, pulse length, and wavelength. A threshold laser intensity for x-ray line production was identified. Information was obtained on the size and duration of the x-ray emission source, in relation to laser parameters. The experimental results, and their impact on backlighting capability for high-density laser function targets, are discussed.
Date: May 12, 1981
Creator: Rupert, V. C.; Matthews, D. L. & Koppel, L. N.
System: The UNT Digital Library
Chemical-kinetic prediction of critical parameters in gaseous detonations (open access)

Chemical-kinetic prediction of critical parameters in gaseous detonations

A theoretical model including a detailed chemical kinetic reaction mechanism for hydrogen and hydrocarbon oxidation is used to examine the effects of variations in initial pressure and temperature on the detonation properties of gaseous fuel-oxidizer mixtures. Fuels considered include hydrogen, methane, ethane, ethylene, and acetylene. Induction lengths are computed for initial pressures between 0.1 and 10.0 atmospheres and initial temperatures between 200K and 500K. These induction lengths are then compared with available experimental data for critical energy and critical tube diameter for initiation of spherical detonation, as well as detonation limits in linear tubes. Combined with earlier studies concerning variations in fuel-oxidizer equivalence ratio and degree of dilution with N/sub 2/, the model provides a unified treatment of fuel oxidation kinetics in detonations. 4 figures, 1 table.
Date: January 12, 1982
Creator: Westbrook, C.K. & Urtiew, P.A.
System: The UNT Digital Library
Currents in ATF (open access)

Currents in ATF

This paper contains viewgraphs on the existence of currents in ATF Torsatron. Current sources like bootstrap, Pfirsch-Schluter, beam driven and flux conserving are investigated and suggestions on minimization are given. (LSP)
Date: November 12, 1987
Creator: Carreras, B. A.; Shaing, K. C.; Dominguez, N.; Lynch, V. E. & Tolliver, J. S.
System: The UNT Digital Library
Compositeness and QCD at the SSC (open access)

Compositeness and QCD at the SSC

Compositeness may be signaled by an increase in the production of high transverse momentum hadronic jet pairs or lepton pairs. The hadronic jet signal competes with the QCD production of jets, a subject of interest in its own right. Tests of perturbative QCD at the SSC will be of special interest because the calculations are expected to be quite reliable. Studies show that compositeness up to a scale of 20 to 35 TeV would be detected in hadronic jets at the SSC. Leptonic evidence would be discovered for scales up to 10 to 20 TeV. The charge asymmetry for leptons would provide information on the nature of the compositeness interaction. Calorimetry will play a crucial role in the detection of compositeness in the hadronic jet signal. Deviations from an e/h response of 1 could mask the effect. The backgrounds for lepton pair production seem manageable. 30 refs., 19 figs., 10 tabs.
Date: October 12, 1987
Creator: Barnes, V.; Blumenfeld, B.; Cahn, R.; Chivukula, S.; Ellis, S.; Freeman, J. et al.
System: The UNT Digital Library
Oxygen-induced reactions at 60 A GeV and 200 A GeV studied by calorimetry (open access)

Oxygen-induced reactions at 60 A GeV and 200 A GeV studied by calorimetry

Results based on calorimetric measurements are presented from reactions of 60 A GeV and 200 A GeV /sup 16/O projectiles with C, Cu, Ag, and Au nuclei. Minimum-bias cross sections are discussed. Energy spectra measured at zero degrees and transverse-energy distributions for the pseudorapidity range 2.4 less than or equal to eta less than or equal to 5.5 are shown. An analysis of the average transverse energy in terms of the number of participating nucleons and the number of binary nucleon-nucleon collision is presented. Estimates of nuclear stopping and of attained energy densities are made. 22 refs., 6 figs., 3 tabs.
Date: November 12, 1987
Creator: Sorensen, S.P.; Albrecht, R.; Awes, T.C.; Baktash, C.; Beckmann, P.; Berger, F. et al.
System: The UNT Digital Library
No pain-no gain: The complex art of soft x-ray laser target design and analysis (open access)

No pain-no gain: The complex art of soft x-ray laser target design and analysis

We review our methodologies in the design and analysis of soft x-ray laser experiments. We convolve large-scale 2-D hydro code output with detailed atomic data bases in a kinetics code with 1-D or 2-D line transfer. The time and space dependent level population data is then post processed further with a beam transport code, including refraction, to predict actual experimental results. While mysteries do remain, we present many examples that show how this complex modeling procedure is crucial in explaining experimental results. 23 refs., 8 figs., 1 tab.
Date: January 12, 1988
Creator: Rosen, M. D.; London, R. A.; Hagelstein, P. L.; Maxon, M. S.; Eder, D. C.; Whitten, B. L. et al.
System: The UNT Digital Library
Some new ideas for Tandem Mirror blankets (open access)

Some new ideas for Tandem Mirror blankets

The Tandem Mirror Reactor, with its cylindrical central cell, has led to numerous blanket designs taking advantage of the simple geometry. Also many new applications for fusion neutrons are now being considered. To the pure fusion electricity producers and hybrids producing fissile fuel, we are adding studies of synthetic fuel producers and fission-suppressed hybrids. The three blanket concepts presented are new ideas and should be considered illustrative of the breadth of Livermore's application studies. They are not meant to imply fully analyzed designs.
Date: October 12, 1981
Creator: Neef, W.S. Jr.
System: The UNT Digital Library
The electromagnetic penguin contribution to /epsilon//prime///epsilon/ for large top quark mass (open access)

The electromagnetic penguin contribution to /epsilon//prime///epsilon/ for large top quark mass

We investigate the electromagnetic penguin contribution to /epsilon//prime///epsilon/ when the top quark mass is large. We find it depends sensitively on the top quark mass. 6 refs., 2 figs.
Date: July 12, 1989
Creator: Randall, L.
System: The UNT Digital Library
Silicon switch development for optical pulse generation in fusion lasers at Lawrence Livermore National Laboratory (open access)

Silicon switch development for optical pulse generation in fusion lasers at Lawrence Livermore National Laboratory

We have been developing a silicon photoconductive switch for use as a Pockels cell driver in the pulse generation systems of the fusion lasers Nova and Novette. The objective has been to make 10 kV switches repeatably and which are reliable on an operating system. We found that nonlinear phenomena in nearly intrinsic silicon caused excessive conduction at high voltage resulting in breakdown. Our experiments with doped material show that this problem can be eliminated, resulting in useful devices.
Date: July 12, 1983
Creator: Wilcox, R. B.
System: The UNT Digital Library
Dense Z-pinch plasmas (open access)

Dense Z-pinch plasmas

Early researchers recogniZed the desirable features of the linear Z-pinch configuration as a magnetic fusion scheme. In particular, a Z-pinch reactor might not require auxiliary heating or external field coils, and could constitute an uncomplicated, high plasma ..beta.. geometry. The simple Z pinch, however, exhibited gross MHD instabilities that disrupted the plasma, and the linear Z pinch was abandoned in favor of more stable configurations. Recent advances in pulsed-power technology and an appreciation of the dynamic behavior of an ohmically heated Z pinch have led to a reexamination of the Z pinch as a workable fusion concept.
Date: July 12, 1985
Creator: Shlachter, J. S.; Hammel, J. E. & Scudder, D. W.
System: The UNT Digital Library