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Important atomic physics issues for ion beam fusion (open access)

Important atomic physics issues for ion beam fusion

This paper suggests several current atomic physics questions important to ion beam fusion. Among the topics discussed are beam transport, beam-target interaction, and reactor design. The major part of the report is discussion concerning areas of research necessary to better understand beam-target interactions. (JDH)
Date: March 19, 1985
Creator: Bangerter, Roger O.
System: The UNT Digital Library
Pion probes of heavy ion collision dynamics (open access)

Pion probes of heavy ion collision dynamics

Pion interferometry data (2-pion correlation) are examined for information on size and lifetime of the pion-emitting matter. The temperatures inferred from pion, proton and kaon spectra are considered. An explanation consistent with the above size and temperature data is proposed. New theoretical Monte Carlo results on spectator effects on heavy-ion pion spectra are presented. 23 refs., 9 figs.
Date: March 1, 1985
Creator: Rasmussen, John O.
System: The UNT Digital Library
Modeling of geothermal systems (open access)

Modeling of geothermal systems

During the last decade the use of numerical modeling for geothermal resource evaluation has grown significantly, and new modeling approaches have been developed. In this paper we present a summary of the present status in numerical modeling of geothermal systems, emphasizing recent developments. Different modeling approaches are described and their applicability discussed. The various modeling tasks, including natural-state, exploitation, injection, multi-component and subsidence modeling, are illustrated with geothermal field examples. 99 refs., 14 figs.
Date: March 1, 1985
Creator: Bodvarsson, G.S.; Pruess, K. & Lippmann, M.J.
System: The UNT Digital Library
Experiment to measure the electron neutrino mass using a frozen tritium source (open access)

Experiment to measure the electron neutrino mass using a frozen tritium source

We are performing an experiment 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 can be precisely 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. We discuss the excited final molecular state calculations and describe the experimental apparatus. 2 references, 6 figures.
Date: March 1, 1985
Creator: Fackler, O.; Mugge, M.; Sticker, H.; White, R.M. & Woerner, R.
System: The UNT Digital Library
Confinement studies of ohmically heated plasmas in TFTR (open access)

Confinement studies of ohmically heated plasmas in TFTR

Systematic scans of density in large deuterium plasmas (a = 0.83 m) at several values of plasma current and toroidal magnetic field strength indicate that the total energy confinement time, tau/sub E/, is proportional to the line-average density anti n/sub e/ and the limiter q. Confinement times of approx. 0.3 s have been observed for anti n/sub e/ = 2.8 x 10/sup 19/ m/sup -3/. Plasma size scaling experiments with plasmas of minor radii a = 0.83, 0.69, 0.55, and 0.41 m at constant limiter q reveal a confinement dependence on minor radius. The major-radius dependence of tau/sub E/, based on a comparison between TFTR and PLT results, is consistent with R/sup 2/ scaling. From the power balance, the thermal diffusivity chi/sub e/ is found to be significantly less than the INTOR value. In the a = 0.41 m plasmas, saturation of confinement is due to neoclassical ion conduction (chi/sub i/ neoclassical >> chi/sub e/).
Date: March 1, 1985
Creator: Efthimion, P. C.; Bretz, N. L.; Bell, M. G.; Bitter, M.; Blanchard, W. R.; Boody, F. et al.
System: The UNT Digital Library
Magnetic fusion 1985: what next (open access)

Magnetic fusion 1985: what next

Recent budget reductions for magnetic fusion have led to a re-examination of program schedules and objectives. Faced with delays and postponement of major facilities as previously planned, some have called for a near-term focus on science, others have stressed technology. This talk will suggest a different focus as the keynote for this conference, namely, the applications of fusion. There is no doubt that plasma science is by now mature and fusion technology is at the forefront. This has and will continue to benefit many fields of endeavor, both in actual new discoveries and techniques and in attracting and training scientists and engineers who move on to make significant contributions in science, defense and industry. Nonetheless, however superb the science or how challenging the technology, these are means, not ends. To maintain its support, the magnetic fusion program must also offer the promise of power reactors that could be competitive in the future. At this conference, several new reactor designs will be described that claim to be smaller and economically competitive with fission reactors while retaining the environmental and safety characteristics that are the hallmark of fusion. The American Nuclear Society is an appropriate forum in which to examine these new …
Date: March 1, 1985
Creator: Fowler, T.K.
System: The UNT Digital Library
18th DOE Nuclear Airborne Waste Management and Air Cleaning Conference: Proceedings. Volume 2 (open access)

18th DOE Nuclear Airborne Waste Management and Air Cleaning Conference: Proceedings. Volume 2

Individual items have been processed separately for the various data bases.
Date: March 1985
Creator: First, M. W.
System: The UNT Digital Library
Permanent magnets for production and use of high energy particle beams (open access)

Permanent magnets for production and use of high energy particle beams

In the last few years, permanent magnet systems have begun to play a dominant role in the generation of synchrotron radiation and the operation of free electron lasers. Similarly, permanent magnets can lead to significant improvements of accelerators and systems that use them. The general conditions are discussed under which one can expect benefits from permanent magnets, and a number of specific applications will be described in detail.
Date: March 1, 1985
Creator: Halbach, K.
System: The UNT Digital Library
QCD calculations on the lattice (open access)

QCD calculations on the lattice

A basic explanation is given of the possibilities and limitations of lattice calculations. In the lattice formulation of QCD, Euclidean space-time is replaced by the vertices of a normally hypercubical lattice, and the dynamic variables are quark fields defined over the sites of the lattice. Gluonic fields are finite elements of the color group. The action contains a pure gauge part and a matter part. Three categories of numerical lattice calculations are described, divided according to the computational resources required. The first category involves calculations which make use of the quenched approximation and where the observables to be evaluated involve no quarks or involve quarks as static spectators only. The second consists of calculations performed within the quenched approximation, but where the observables involve propagating quarks. The most complex calculations fall in the final category, those where one tries to incorporate the dynamic effects from creation and annihilation of virtual quark pairs. 8 refs. (LEW)
Date: March 1, 1985
Creator: Rebbi, C.
System: The UNT Digital Library
Review of short wavelength lasers (open access)

Review of short wavelength lasers

There has recently been a substantial amount of research devoted to the development of short wavelength amplifiers and lasers. A number of experimental results have been published wherein the observation of significant gain has been claimed on transitions in the EUV and soft x-ray regimes. The present review is intended to discuss the main approaches to the creation of population inversions and laser media in the short wavelength regime, and hopefully aid workers in the field by helping to provide access to a growing literature. The approaches to pumping EUV and soft x-ray lasers are discussed according to inversion mechanism. The approaches may be divided into roughly seven categories, including collisional excitation pumping, recombination pumping, direct photoionization and photoexcitation pumping, metastable state storage plus optical pumping, charge exchange pumping, and finally, the extension of free electron laser techniques into the EUV and soft x-ray regimes. 250 references.
Date: March 18, 1985
Creator: Hagelstein, P.L.
System: The UNT Digital Library
Effects of laser radiation on surfaces and coatings (open access)

Effects of laser radiation on surfaces and coatings

A summary is given of the principal aspects of laser-induced damage to polished optical surfaces and dielectric, thin-film, high-reflectivity and antireflective coatings. Methods for producing porous antireflective surfaces and coatings and their damage properties are also reviewed. Finally, new areas of basic research to solve current and future problems are addressed.
Date: March 1, 1985
Creator: Lowdermilk, W.H.
System: The UNT Digital Library
MIG: MCNP input generator for EFFI magnet geometries (open access)

MIG: MCNP input generator for EFFI magnet geometries

A computer code, MIG, has been developed to interface the magnet design and the three-dimensional Monte Carlo code MCNP to perform neutronics design analyses. MIG prepares all the required MCNP cells and surfaces to simulate the magnets described in EFFI input. Extra zones with different materials could be added to envelop or divide the winding packs of the magnets. Examples of the input and output of MIG used by MCNP are given to illustrate the different capabilities of MIG.
Date: March 1, 1985
Creator: Attaya, H. & Gohar, Y.
System: The UNT Digital Library
Design of aggressive superconducting TFCX magnet systems (open access)

Design of aggressive superconducting TFCX magnet systems

An investigation of several fundamental limits of machine design indicate that a machine fitting the specifications of the Tokamak Fusion Core Experiment (TFCX) can be built with both a superconducting toroidal field (TF) coil set and a plasma major radius of less than 3.2 m. This small size is achieved by accepting a peak nuclear heat load of 50 (kW)(m/sup -3/) in the TF coin inner leg while operating at a 10-T maximum field with a current density of 35 (A)(mm/sup -2/) in the winding pack. This performance, high by traditional standards, is justified based on developments in forced flow conductor technology using Nb/sub 3/Sn composite superconductors.
Date: March 29, 1985
Creator: Miller, J. R.
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
Study of the equilibrium vacancy ensemble in aluminum using 1D- and 2D-angular correlation of annihilation radiation (open access)

Study of the equilibrium vacancy ensemble in aluminum using 1D- and 2D-angular correlation of annihilation radiation

One- and two-dimensional angular correlation of positron-electron annihilation radiation (1D and 2D-ACAR) data have been obtained between 293 and 903 K for single crystals of aluminum. The peak counting rates vs temperature, which were measured using the 1D-ACAR technique, provide a model independent value for the temperature dependence of the positron trapping probability. Using these results it is possible to strip out the Bloch state contribution from the observed 2D-ACAR surfaces and then compare the resulting defect ACAR surfaces to calculated 2D-ACAR surfaces for positrons annihilating from the Bloch, monovacancy, and divacancy-trapped states. The result of this comparison is that the presence of an increasing equilibrium divacancy population is consistent with the observed temperature dependence of ACAR data at high temperature in Al and that the present results when compared to earlier studies on Al indicate that the ratio of the trapping rates at divacancies and monovacancies is of order two.
Date: March 12, 1985
Creator: Fluss, M.J.; Berko, S.; Chakraborty, B.; Hoffmann, K.R.; Lippel, P. & Siegel, R.W.
System: The UNT Digital Library
Exact Monte Carlo for molecules (open access)

Exact Monte Carlo for molecules

A brief summary of the fixed-node quantum Monte Carlo method is presented. Results obtained for binding energies, the classical barrier height for H + H2, and the singlet-triplet splitting in methylene are presented and discussed. 17 refs.
Date: March 1, 1985
Creator: Lester, W. A. Jr. & Reynolds, P. J.
System: The UNT Digital Library
Resolvability of positron decay channels (open access)

Resolvability of positron decay channels

Many data analysis treatments of positron experiments attempt to resolve two or more positron decay or exist channels which may be open simultaneously. Examples of the need to employ such treatments of the experimental results can be found in the resolution of the constituents of a defect ensemble, or in the analysis of the complex spectra which arise from the interaction of slow positrons at or near the surfaces of solids. Experimental one- and two-dimensional angular correlation of annihilation radiation experiments in Al single crystals have shown that two defect species (mono- and divacancies) can be resolved under suitable conditions. Recent experiments at LLNL indicate that there are a variety of complex exit channels open to positrons interacting at surfaces, and ultimely these decay channels must also be suitably resolved from one another. 6 refs., 4 figs.
Date: March 7, 1985
Creator: Fluss, M.J.; Howell, R.H.; Rosenberg, I.J. & Meyer, P.
System: The UNT Digital Library
Kinetics of combined SO/sub 2//NO in flue gas clean-up (open access)

Kinetics of combined SO/sub 2//NO in flue gas clean-up

The kinetics of reactions involving SO/sub 2/, NO, and ferrous chelate additives in wet flue gas simultaneous desulfurization and denitrification scrubbers are discussed. The relative importance of these reactions are assessed. The relevance of these reactions to spray dryer processes for combined SO/sub 2//NO flue gas clean-up is addressed. 37 refs., 7 figs.
Date: March 1, 1985
Creator: Chang, S. G. & Littlejohn, D.
System: The UNT Digital Library
Eighteenth LAMPF users group meeting: proceedings (open access)

Eighteenth LAMPF users group meeting: proceedings

The Eighteenth Annual LAMPF Users Group Meeting was held October 29-30, 1984, at the Clinton P. Anderson Meson Physics Facility. The program included a number of invited talks on various aspects of nuclear and particle physics as well as status reports on LAMPF and discussions of upgrade options. The LAMPF working groups met and discussed plans for the secondary beam lines, experimental programs, and computing facilities.
Date: March 1, 1985
Creator: Bradbury, J.N. (comp.)
System: The UNT Digital Library
Plasma wake field accelerator (open access)

Plasma wake field accelerator

A new scheme of electron acceleration, employing relativistic electron bunches in a cold plasma, is analyzed. The wake field of a leading bunch is derived in a single-particle model. We then extend the model to include finite bunch length effect. In particular, we discuss the relation between the charge distributions of the driving bunch and the energies transformable to the trailing electrons. It is shown that for symmetric charge distribution of the driving bunches, the maximum energy gain for a driven electron is 2..gamma../sub 0/mc/sup 2/. This limitation can be overcome by introducing asymmetric charge distributions. 13 refs., 5 figs.
Date: March 1, 1985
Creator: Chen, P. & Dawson, J.M.
System: The UNT Digital Library
Use of environmental health-risk analysis for managing toxic substances (open access)

Use of environmental health-risk analysis for managing toxic substances

This paper presents a set of simple models used to assess health risks based on toxicity, environmental mobility and persistence. These models use a representative landscape in order to describe the steady-state distribution of arsenic, tritiated water, and TCDD as a result of continuous additions to soil. This information is used to assess potential exposures. Application of the screening model to three chemically different carcinogens reveals that the environmental health risk does not scale with direct measures of toxicity. As estimated here, the environmental health risk of TCDD relative to tritiated water and arsenic is roughly an order of magnitude less than its cancer potency relative to these compounds. The difference is attributable in large part to the immobility of TCDD relative to tritium and the lower persistence of TCDD compared to arsenic. The purpose is to present a simple procedure for using the relative behavior of toxic species under prototype conditions as a basis for risk management. 21 refs., 4 tabs. (ACR)
Date: March 1, 1985
Creator: McKone, T.E.
System: The UNT Digital Library
Fixed-target physics at Fermilab (open access)

Fixed-target physics at Fermilab

The Fermilab Energy Saver is now successfully commissioned and fixed-target experimentation at high energy (800 GeV) has begun. In addition, a number of new experiments designed to exploit the unique features of the Tevatron are yet to come on-line. In this talk, we will review recent accomplishments in the fixed-target program and describe experiments in progress and others yet to come.
Date: March 1, 1985
Creator: Bjorken, J. D.
System: The UNT Digital Library
Friction in nuclear dynamics (open access)

Friction in nuclear dynamics

The problem of dissipation in nuclear dynamics is related to the breaking down of nuclear symmetries and the transition from ordered to chaotic nucleonic motions. In the two extreme idealizations of the perfectly Ordered Regime and the fully Chaotic Regime, the nucleus should behave as an elastic solid or an overdamped fluid, respectively. In the intermediate regime a complicated visco-elastic behaviour is expected. The discussion is illustrated by a simple estimate of the frequency of the giant quadrupole resonance in the Ordered Regime and by applications of the wall and window dissipation formulae in the Chaotic Regime. 51 refs.
Date: March 1, 1985
Creator: Swiatecki, W.J.
System: The UNT Digital Library
18th DOE Nuclear Airborne Waste Management and Air Cleaning Conference: Proceedings. Volume 1 (open access)

18th DOE Nuclear Airborne Waste Management and Air Cleaning Conference: Proceedings. Volume 1

Individual items have been processed separately for the various data bases.
Date: March 1, 1985
Creator: First, M. W.
System: The UNT Digital Library