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Recent US target-physics-related research in heavy-ion inertial fusion: simulations for tamped targets and for disk experiments in accelerator test facilities (open access)

Recent US target-physics-related research in heavy-ion inertial fusion: simulations for tamped targets and for disk experiments in accelerator test facilities

Within the last few years, there have also appeared in the Heavy-Ion Fusion literature several studies of targets which have outer tampers. One-dimensional simulations indicate higher target gains with a judicious amount of tamping. But for these targets, a full investigation has not been carried through in regards to conservative criteria for fluid instabilities as well as reasonable imperfections in target fabrication and illumination symmetry which all affect target ignition and burn. Comparisons of these results with the gain survey of Part I would have to be performed with care. These calculations suggest that experiments relating to high temperature disk heating, as well as beam deposition, focusing and transport can be performed within the context of current design proposals for accelerator test-facilities. Since the test-facilities have lower ion kinetic energy and beam pulse power as compared to reactor drivers, we achieve high-beam intensities at the focal spot by using short focal distance and properly designed beam optics.
Date: June 24, 1982
Creator: Mark, J.W.K.
System: The UNT Digital Library
Time-Dependent Two-Dimensional Radiation Hydrodynamics of Accreting Matter Onto Highly Magnetized Neutron Stars (open access)

Time-Dependent Two-Dimensional Radiation Hydrodynamics of Accreting Matter Onto Highly Magnetized Neutron Stars

We present for the first time, the self-consistent solution of the two-dimensional, time-dependent equations of radiation-hydrodynamics governing the accretion of matter onto the highly magnetized polar caps of luminous x-ray pulsars. The calculations show a structure in the accretion column very different from previous one-zone uniform models. We have included all the relevant magnetic field corrections to both the hydrodynamics and the radiative transport. We include a new theory for the diffusion and advection of both radiation energy density and photon number density. For initially uniformly accreting models with super-Eddington flows, we have uncovered evidence of strong radiation-driven outflowing optically thin radiation filled regions of the accretion column embedded in optically-thick inflowing plasma. The development of these photon bubbles'' have growth times on the order of a millisecond and show fluctuations on sub-millisecond timescales. The photon bubbles are likely to be a consequence of convective over-stability and may result in observable fluctuations in the emitted luminosity leading to luminosity dependent changes in the pulse profile. This may provide important new diagnostics for conditions in accreting x-ray pulsars. 13 refs., 18 figs.
Date: November 24, 1989
Creator: Klein, R.I. (California Univ., Los Angeles, CA (USA). Dept. of Astronomy Lawrence Livermore National Lab., CA (USA) California Univ., Los Angeles, CA (USA). Inst. of Geophysics and Planetary Physics) & Arons, J. (California Univ., Berkeley, CA (USA). Dept. of Astronomy California Univ., Los Angeles, CA (USA). Inst. of Geophysics and Planetary Physics CEA Centre d'Etudes Nucleaires de Saclay, 91 -
System: The UNT Digital Library
/sup 56/Ni and the light curve of Type I supernova (open access)

/sup 56/Ni and the light curve of Type I supernova

The explanation of SN Type I by radioactive decay of /sup 56/Ni requires a relatively small value of the transparency function M/sub ej//v/sub 9//sup 2/ = 0.22 in units of M/sub solar/'s and 10/sup 9/ cm s/sup -1/ to explain the light curve. A minimum mass of /sup 56/Ni is required to explain the peak and near peak luminosity. Subsequent radioactive decay energy must escape in some other form than optical light in order to explain the rapid early and late time decay. Early ultraviolet and infrared radiation are excluded as sinks of energy by observations. PdV work is excluded by theory. The energy loss due to the escape of gamma rays and ..beta../sup +/'s with the above value of M/sub ej//v/sub 9//sup 2/ gives good agreement with the light curve after maximum, provided essentially all the trapped energy is converted to optical light. The peak of SN 1972e is explained with the above transparency value M/sub ej//v/sub 9//sup 2/ = 0.22 and mass of /sup 56/Ni of 0.25 M/sub solar/ or 0.4 M/sub solar/, and a distance of 3.2 Mpc or 4 Mpc, respectively. These values depend critically upon the prediscovery report of Austin (1972), and the assumption again …
Date: July 24, 1980
Creator: Colgate, S.A. & Petschek, A.G.
System: The UNT Digital Library
Evaluation of soil damping techniques used in soil structure interaction analysis of a nuclear power plant (open access)

Evaluation of soil damping techniques used in soil structure interaction analysis of a nuclear power plant

A prediction of dynamic soil properties at the site of a nuclear power plant plays a very important role in the seismic analysis of the facility. Conventional modal analysis procedures can accommodate virtually any range of equivalent elastic soil stiffness which is used to characterize the site. However, high radiation damping associated with energy dissipation in the soil half-space is difficult to accommodate in an elastic modal solution to the dynamic problem. Several methods are available to combine the soil damping with the structural damping in a composite modal damping coefficient. However, even with this convenient representation, the resulting large fractions of critical damping can make modal solutions to the problems suspect. This paper is based on experience gained in this area during studies performed for the Nuclear Regulatory Commission involving seismic analyses of power plants.
Date: February 24, 1982
Creator: Nelson, T.A.
System: The UNT Digital Library
Nuclear interactions of heavy ions (open access)

Nuclear interactions of heavy ions

A possible source of preheat for heavy ion driven inertial fusion targets is the production of fast precursors by nuclear interactions between the incident heavy ions and the outer parts of the target. A model has been developed which roughly describes these interactions for all beam-target combinations for all incident energies. This interaction model has been applied to a specific capsule design. The resultant preheat is an order of magnitude below the level which could impair target performance.
Date: February 24, 1982
Creator: Tabak, M. & Bangerter, R.
System: The UNT Digital Library
Geothermal Symposium: Low-Temperature Utilization, Heat-Pump Applications, District Heating (open access)

Geothermal Symposium: Low-Temperature Utilization, Heat-Pump Applications, District Heating

Separate abstracts are prepared for twelve papers presented at the symposium. (MCW)
Date: September 24, 1980
Creator: Bloomquist, R. G.
System: The UNT Digital Library
Wear and corrosion performance of metallurgical coatings in sodium (open access)

Wear and corrosion performance of metallurgical coatings in sodium

The friction, wear, and corrosion performance of several metallurgical coatings in 200 to 650/sup 0/C sodium are reviewed. Emphasis is placed on those coatings which have successfully passed the qualification tests necessary for acceptance in breeder reactor environments. Tests include friction, wear, corrosion, thermal cycling, self-welding, and irradiation exposure under as-prototypic-as-possible service conditions. Materials tested were coatings of various refractory metal carbides in metallic binders, nickel-base and cobalt-base alloys and intermetallic compounds such as the aluminides and borides. Coating processes evaluated included plasma spray, detonation gun, sputtering, spark-deposition, and solid-state diffusion.
Date: April 24, 1980
Creator: Johnson, R. N. & Farwick, D. G.
System: The UNT Digital Library
Mechanical design of the Tandem Mirror Experiment Upgrade vacuum system (open access)

Mechanical design of the Tandem Mirror Experiment Upgrade vacuum system

The Tandem Mirror Experiment Upgrade (TMX Upgrade) vacuum system uses most of the vacuum system from the original TMX and substantially increases its capabilities. The vacuum system provides the main structure for the experimental apparatus, as well as providing and maintaining the vacuum environment. The vacuum vessel provides the structure supporting all magnets, as they are contained inside the vacuum vessel, all of the neutral-beam injectors, and the various diagnostics. The vessel provides the main vacuum enclosure and the various access ports required by the magnet system, injector system, internal vacuum system, and plasma diagnostics. The vacuum environment is created and maintained by two systems, the external vacuum system and the internal vacuum system. The external system consists of mechanical pumps, turbopumps, and cryopumps, and creates a vacuum inside the vessel down to a minimum pressure of 10/sup -6/ Torr. The internal vacuum system further reduces the pressure into the 10/sup -8/ Torr range and provides the fast pumping required to handle the excess gas from the neutral-beam injector system during a plasma shot. The internal vacuum system consists of titanium sublimators and liquid nitrogen (LN) liners that separate the vacuum vessel into various pumping regions.
Date: September 24, 1981
Creator: Lang, D. D.; Calderon, M. O.; Thomas, S. R. & Garner, D. R.
System: The UNT Digital Library
Early history of computer simulations in statistical mechanics (open access)

Early history of computer simulations in statistical mechanics

A history of the early use of the Monte Carlo method is presented.
Date: June 24, 1985
Creator: Wood, W.W.
System: The UNT Digital Library
Hadron masses in lattice gauge theories: The inclusions of dynamical fermions (open access)

Hadron masses in lattice gauge theories: The inclusions of dynamical fermions

Hadron masses are calculated on an 8/sup 3/ /times/ 16 lattice using four flavors of staggered fermion to generate the gauge configurations, but using Wilson fermions to calculate the hadron propagators. The identification of a value of the Wilson hopping parameter with the value of the bare quark mass used in the simulations is discussed.
Date: November 24, 1987
Creator: Richards, D.G.
System: The UNT Digital Library
Tandem mirror fusion-fission hybrid studies (open access)

Tandem mirror fusion-fission hybrid studies

Initial tandem mirror hybrid studies predict the ability to produce large amounts of fissile fuel (2 to 7 tons U233 per year from a 4000 MW plant) at a cost that adds less than 25% to the cost of power from a LWR.
Date: April 24, 1980
Creator: Lee, J. D.
System: The UNT Digital Library
Pion induced double-charge exchange above the resonance (open access)

Pion induced double-charge exchange above the resonance

The zero degree excitation function for ({pi}{sup +}, {pi}{sup -}) is calculated for pion energies of 300 to 1400 MeV assuming a sequential mechanism. The cross section around 1225 MeV is 10{sup 4} smaller than at 800 MeV. Experiments at this energy should be ideal for searches for effects due to exchange currents, and other non-conventional mechanisms. 15 refs.
Date: October 24, 1989
Creator: Oset, E.; Strottman, D. (Valencia Univ. (Spain). Dept. de Fisica Teorica & Los Alamos National Lab., NM (USA))
System: The UNT Digital Library
Optical coatings for laser fusion applications (open access)

Optical coatings for laser fusion applications

Lasers for fusion experiments use thin-film dielectric coatings for reflecting, antireflecting and polarizing surface elements. Coatings are most important to the Nd:glass laser application. The most important requirements of these coatings are accuracy of the average value of reflectance and transmission, uniformity of amplitude and phase front of the reflected or transmitted light, and laser damage threshold. Damage resistance strongly affects the laser's design and performance. The success of advanced lasers for future experiments and for reactor applications requires significant developments in damage resistant coatings for ultraviolet laser radiation.
Date: April 24, 1980
Creator: Lowdermilk, W.H.; Milam, D. & Rainer, F.
System: The UNT Digital Library
Multiple electron capture in close ion-atom collisions (open access)

Multiple electron capture in close ion-atom collisions

Collisions in which a fast highly charged ion passes within the orbit of K electron of a target gas atom are selected by emission of a K x-ray from the projectile or target. Measurement of the projectile charge state after the collision, in coincidence with the K x-ray, allows measurement of the charge-transfer probability during these close collisions. When the projectile velocity is approximately the same as that of target electrons, a large number of electrons can be transferred to the projectile in a single collision. The electron-capture probability is found to be a linear function of the number of vacancies in the projectile L shell for 47-MeV calcium ions in an Ar target. 18 refs., 9 figs.
Date: July 24, 1989
Creator: Schlachter, A. S.; Stearns, J. W.; Berkner, K. H.; Bernstein, E. M.; Clark, M. W.; DuBois, R. D. et al.
System: The UNT Digital Library
Resource assessment/commercialization planning meeting (open access)

Resource assessment/commercialization planning meeting

The U.S. Department of Energy, Division of Geothermal Energy and Division of Geothermal Resource Management, sponsored a Resource Assessment/Commercialization Planning meeting in Salt Lake City on January 21-24, 1980. The meeting included presentations by state planning and resource teams from all DOE regions. An estimated 130 people representing federal, state and local agencies, industry and private developers attended.
Date: January 24, 1980
Creator: unknown
System: The UNT Digital Library
Microscopic calculation for deformed nuclei (open access)

Microscopic calculation for deformed nuclei

The microscopic basis of the Interacting Boson Model for deformed nuclei is discussed. The IBM Hamiltonian is constructed microscopically in the following two steps. In the first step, the collective nucleon pairs of J = 0/sup +/ (S), 2/sup +/ (D), etc. are mapped onto the corresponding bosons. Nucleon-nucleon interactions are also mapped onto boson-boson interactions. This mapping method for deformed nuclei was proposed recently, and it turned out that this method is consistent with the Hartree-Fock-Bogoliubov + angular momentum projection calculation. Low-lying collective states primarily consist of S and D pairs. Consequently, the corresponding boson states mainly consist of s and d bosons, while there are some admixture of g-bosons. In the second step, effects of these g-bosons are included within the s-d boson space by a unitary transformation which transforms a combination of d and g bosons into a new d-boson. By minimizing the coupling between new d and g bosons with an appropriate mixing angle, one can neglect the coupling and obtain the IBM Hamiltonian with s and d bosons. It is demonstrated that the s-d Hamiltonian thus derived indeed reproduces spectra of the original s-d-g Hamiltonian.
Date: September 24, 1984
Creator: Otsuka, Takaharu
System: The UNT Digital Library
Relation between shock strength and strain-rate plasticity at maximum deviatoric stress (open access)

Relation between shock strength and strain-rate plasticity at maximum deviatoric stress

Using Wallace's analysis for steady weak shocks, this paper establishes for Cu, Ur, and 6061T6Al an approximate relations between the shock strength and the maximum deviatoric stress, tau/sub m/, and plastic strain at tau/sub m/. In addition it is shown that the plastic strain rate is very nearly proportional to the total normal strain rate at tau/sub m/. These results and the universal shock strength/strain rate relation of Swegle and Grady are used to draw conclusions about the general plasticity constitutive relation.
Date: June 24, 1987
Creator: Tonks, D.L.
System: The UNT Digital Library
400 MeV upgrade for the Fermilab linac (open access)

400 MeV upgrade for the Fermilab linac

Fermilab has plans for a comprehensive accelerator upgrade to open new possibilities for both the fixed target and collider experimental programs. An early step in this program is to increase the energy of the linac from 200 to 400 MeV by replacing the last four of its nine 201 MHz Alvarez tanks with twenty-eight 805 MHz side-coupled cavity chains operating at about 8 MV/m average axial field. The principal purpose is to reduce the incoherent spacecharge tuneshift at injection into the Booster which currently limits both the brightness of the beam, an important determinant of collider luminosity, and total intensity to produce both the antiprotons for the collider and the beams to fixed target experimental areas. Other consequences of higher Booster injection energy expected to contribute to some degree of higher intensity limits and improved operational characteristics include improved quality of the guide field at injection, reduced frequency swing for the rf systems, and smaller emittance for the injected beam. The linac upgrade project has moved from a 1986 study through a development project including structure models and numerical studies to a full-feature module prototyping starting this year.
Date: March 24, 1989
Creator: MacLachlan, J.A.
System: The UNT Digital Library
Surface studies of UFe2 and evaluation of its catalytic properties with a 2H2:CO mixture (open access)

Surface studies of UFe2 and evaluation of its catalytic properties with a 2H2:CO mixture

The reactivity of UFe2 with O2, CO and CO2 were studied using x-ray photoelectron spectroscopy (XPS). Adsorption of O2 on clean UFe2 surfaces (Fe/U approx. = 2.0), produced by argon-ion sputtering, leads to the formation of UO2 and depletion of Fe from the surface layer probed by XPS (Fe/U approx. = 0.8). The oxidation state of Fe in this layer, as determined by XPS (Fe 2p/sub 3/2/ = 710.4 eV), is between Fe S and Fe T of pure Fe oxides. Exposure of sputtered-clean UFe2 to CO and CO2 results in a slight broadening of the U 4f peaks, indicating U oxidation, and some Fe depletion in the analyzed layer (Fe/U approx. = 1.7). The O ls (530.2 and 530.4 eV for CO and CO2, respectively) and C ls (282.7 and 282.6 eV for CO and CO2, respectively) indicate that dissociative chemisorption to O and C atoms occurs. UFe2 ground into a fine powder was tested as a catalyst in a differential high-pressure flow reactor with a 2H2:CO gas mixture. A significant amount of methanol and hydrocarbons are produced at 577K; while hydrocarbons are the main products (>99%) at 739K. XPS analysis of the used catalyst indicates that U is …
Date: March 24, 1987
Creator: Schultz, J.; Naegele, J.; Spirlet, J.C. & Colmenares, C.
System: The UNT Digital Library
Full length prototype SSC dipole test results (open access)

Full length prototype SSC dipole test results

Results are presented from tests of the first full length prototype SSC dipole magnet. The cryogenic behavior of the magnet during a slow cooldown to 4.5K and a slow warmup to room temperature has been measured. Magnetic field quality was measured at currents up to 2000 A. Averaged over the body field all harmonics with the exception of b/sub 2/ and b/sub 8/ are at or within the tolerances specified by the SSC Central Design Group. (The values of b/sub 2/ and b/sub 8/ result from known design and construction defects which will be be corrected in later magnets.) Using an NMR probe the average body field strength is measured to be 10.283 G/A with point to point variations on the order of one part in 1000. Data are presented on quench behavior of the magnet up to 3500 A (approximately 55% of full field) including longitudinal and transverse velocities for the first 250 msec of the quench.
Date: April 24, 1987
Creator: Strait, J.; Brown, B.C.; Carson, J.; Engler, N.; Fisk, H.E.; Hanft, R. et al.
System: The UNT Digital Library
High-frequency microinstabilities in hot-electron plasmas (open access)

High-frequency microinstabilities in hot-electron plasmas

Instabilities with frequencies in the neighborhood of the electron cyclotron frequency are of interest in determining stable operating regimes of hot-electron plasmas in EBT devices and in tandem mirrors. Previous work used model distributions significantly different than those suggested by recent Fokker-Planck studies. We use much more realistic model distributions in a computer code that solves the full electromagnetic dispersion relation governing longitudinal and transverse waves in a uniform plasma. We allow for an arbitrary direction of wave propagation. Results for the whistler and upper-hybrid loss-cone instabilities are presented.
Date: November 24, 1981
Creator: Chen, Y. J.; Nevins, W. M. & Smith, G. R.
System: The UNT Digital Library
Relativistic nuclear fluid dynamics and VUU kinetic theory (open access)

Relativistic nuclear fluid dynamics and VUU kinetic theory

Relativistic kinetic theory may be used to understand hot dense hadronic matter. We address the questions of collective flow and pion production in a 3 D relativistic fluid dynamic model and in the VUU microscopic theory. The GSI/LBL collective flow and pion data point to a stiff equation of state. The effect of the nuclear equation of state on the thermodynamic parameters is discussed. The properties of dense hot hadronic matter are studied in Au + Au collisions from 0.1 to 10 GeV/nucleon. 22 refs., 5 figs.
Date: August 24, 1987
Creator: Molitoris, J.J.; Hahn, D.; Alonso, C.; Collazo, I.; D'Alessandris, P.; McAbee, T. et al.
System: The UNT Digital Library
Role of the Materials Review Board and the nuclear waste materials handbook (open access)

Role of the Materials Review Board and the nuclear waste materials handbook

The US Department of Energy has established an organizational structure that assures the quality of key data identified as being important to the licensing of a nuclear waste repository by the US Nuclear Regulatory Commission. The Materials Characterization Center collects and/or develops the test methods needed to obtain the data, and acts as a clearinghouse for all data obtained by the methods, regardless of source. The Materials Review Board reviews both test methods and test data submitted to it, and approves them if they meet the rigorous criteria and standards that have been established. The appearance of test methods and test data in the Nuclear Waste Materials Handbook is evidence that the material has undergone intensive review and can be used with confidence within the bounds of the application specified. The principal use of the Handbook is in the repository licensing process.
Date: March 24, 1985
Creator: Steindler, M.J. & Seefeldt, W.B.
System: The UNT Digital Library
Electron correlation in the continuum (open access)

Electron correlation in the continuum

We consider a class of problems, notably double ionization, which require accurate descriptions of correlation in both the initial and final states. Methods are presented for representing correlated wavefunctions on a basis spline lattice, and for calculating bound-continuum transition probabilities. 13 refs.
Date: July 24, 1989
Creator: Bottcher, C. & Strayer, M. R.
System: The UNT Digital Library