All available oxygen potential-temperature-composition data for the calcium fluorite-structure <PuO/sub 2-x/> phase were retrieved from the literature and utilized in the development of a binary solid solution representation of the phase. The data and phase relations are found to be best described by a solution of (Pu/sub 4/3/O/sub 2/) and (PuO/sub 2/) with a temperature dependent interaction energy. The fluorite-structure <U/sub 1-z/Pu/sub z/O/sub w/> is assumed to be represented by a combination of the binaries <PuO/sub 2-x/> and <UO/sub 2+-x/>, and thus treated as a solution of (Pu/sub 4/3/O/sub 2/), (PuO/sub 2/), (UO/sub 2/), and either (U/sub 2/O/sub 4/./sub 5/) or (U/sub 3/O/sub 7/). The resulting equations well reproduce the large amount of oxygen potential-temperature-composition data for the mixed oxide system, all of which were also retrieved from the literature. These models are the first that appear to display the appropriate oxygen potential-temperature-composition and phase relation behavior over the entire range of existence for the phases. 39 refs., 10 figs., 3 tabs.

Numerical simulation techniques are used to produce a probable range of predicted values from estimates of uncertainty assigned to the parameters of radiological assessment models. This range is used to indicate the uncertainty in the model's prediction. The importance of individual parameters and exposure pathways is determined by their relative contribution to this simulated uncertainty index. The major pathways of exposure to humans resulting from the airborne emissions of /sup 99/Tc involve the consumption of vegetables, vegetable products, and poultry eggs. The most important model parameters are related to the mobility of /sup 99/Tc in soil, the incorporation of /sup 99/Tc into the edible portions of crops, its transfer from vegetation to poultry eggs, and its atmospheric deposition. Uncertainty in the dose for individuals exposed to /sup 99/Tc-contaminated liquid discharges is dominated by the bioaccumulation of this isotope in aquatic food chains and by the possibility that contaminated surface water will be used as a source of drinking water. Results suggest that future reductions in the present estimates of uncertainty will lead to the dismissal of /sup 99/Tc as an environmentally important radionuclide, provided that de minimis dose levels are eventually adopted and releases of /sup 99/Tc from individual nuclear …

Topics and ideas addressed include: (1) the regional extent of the Rio Grande rift; (2) the structure of the crust and upper mantle; (3) whether the evidence for an axile dike in the lower crust is compelling; (4) the nature of faulting and extension in the crust; and (5) the structural and magmatic development of the rift. 88 references, 5 figures.

A shape resonance is a quasibound state in which a particle is temporarily trapped by a potential barrier (i.e., the shape of the potential), through which it may eventually tunnel and escape. This simple mechanism plays a prominent role in a variety of excitation processes in molecules, ranging from vibrational excitation by slow electrons to ionization of deep core levels by x-rays. Moreover, their localized nature makes shape resonances a unifying link between otherwise dissimilar circumstances. One example is the close connection between shape resonances in electron-molecule scattering and in molecular photoionization. Another is the frequent persistence of free-molecule shape resonant behavior upon adsorption on a surface or condensation into a molecular solid. The main focus of this article is a discussion of the basic properties of shape resonances in molecular fields, illustrated by the more transparent examples studied over the last ten years. Other aspects to be discussed are vibrational effects of shape resonances, connections between shape resonances in different physical settings, and examples of shape resonant behavior in more complex cases, which form current challenges in this field.

The principles and design choices for cyclotrons as mass spectrometers are described. They are illustrated by examples of cyclotrons developed by various groups for this purpose. The use of present high energy cyclotrons for mass spectrometry is also described. 28 references, 12 figures.

For heating plasmas and for current drive in some fusion reactors, high energy neutral beams may be required. The high neutralization efficiency of H/sup -/ or D/sup -/ ions makes them favorable to form neutral atoms with energies in excess of 160 keV. It has been shown that a steady-state H/sup -/ ion beam with current greater than 1 A can be generated by a surface conversion type source with Mo being used as the converter material. In order to achieve the proper cesium coverage and thereby increasing the H/sup -/ ion yield, the application of porous cesium-dispensing converters is being investigated. It is also possible to optimize the H/sup -/ production by choosing the proper converter material. In this paper, we compare the negative ion yield generated by different materials (such as Mo, Ti, V, Nb, Pt, Pd, Rh, Cu, Ta, Al, Au, LaB/sub 6/ and stainless-steel) in the pure hydrogen and cesium-hydrogen modes of operation.

Negative ions can be produced by a desorption process when energetic positive hydrogen ions impinge on the surface of reactor walls. The relative yield of different negative ions generated from various surface materials (such as Mo, Pt, Pd, Rh, Cu, Ta, Au, C, TiC and stainless-steel) have been compared in a multicusp plasma source. The negative ions generated are self-extracted from the source, and are identified by a mass spectrometer. The total negative ion current is measured by a Faraday cup.

The chapters of this volume represent the invited papers delivered at the conference. They are arranged according to thermatic proximity beginning with atoms and continuing with molecules and surfaces. Section headings include multiphoton processes in atoms, field fluctuations and collisions in multiphoton process, and multiphoton processes in molecules and surfaces. Abstracts of individual items from the conference were prepared separately for the data base. (GHT)

Energy and angular distributions of neutral ..pi.. mesons emitted in reactions of 35-MeV/u /sup 14/N + A1, Ni, and W have been measured by using beams from the MSU K = 500 cyclotron. The measurements continue a long tradition of subthreshold (in the nucleon-nucleon sense) production of ..pi.. mesons, extending back to the first artificial production by Gardner and Lattes using 75-MeV/u ..cap alpha..-particle beams from the UCRL 184'' synchrocyclotron. Comparisons are made with theory, ascribing the present production to mechanisms of varying degree of collectivity, and some suggestions are made concerning future experimental work. 34 references.

The theory of atomic collisions has two ingredients: collision theory and atomic structure theory. The collision theories differ with respect to (A) the collision dynamics and (B) the treatment of the relative motion of the projectile and target nuclei. With regard to the dynamics multiple vacancy production is of fundamental interest because it is a signature for and probe of strong interactions between the projectile and the target electrons. For projectiles of large nuclear charge, Z/sub p/, especially for those which are highly stripped so as to have a large ionic charge, q, the interaction becomes strong enough to give a high probability of multiple vacancy production and a breakdown of perturbation theory. The familiar first and second Born approximations and their off-shoots cease to be adequate. Not even the recent strong-potential Born approximation (see Taulbjerg 1984) is sufficient, because the weaker of the potentials generated by the projectile and the target nuclei, respectively, is treated in first order. One needs a unitary, non-perturbative collision theory. At present this is generally available for multiple vacancy production only in the form of the highly numerical coupled channels theory (Becker et al. 1983, 1984b). For special problems analytically tractable models have been …

The Los Alamos National Laboratory has begun a program to share its scientific and technological expertise with students and teachers in the surrounding area. The goal of the Laboratory's Educational Outreach Program is to stimulate an awareness of professional opportunities in the sciences and engineering.

A description is presented of the plasma-surface interactions in thermal-barrier tandem-mirror machines. The thermal-barrier mode of axial confinement is an integral part of a tandem mirror, and it dictates the required plasma conditions, particularly at the surface of the plasma. For this reason, a qualitative discussion of the thermal barrier is presented first in Section 2. A brief description of the experimental configuration used in tandem mirrors to create the thermal barrier is then examined in detail in Section 3; the TMX-U and MFTF-B machines are used as specific examples. In Section 4, the relevant plasma-surface interaction issues are addressed, and experimental results from currently operating tandom mirror machines are included. Section 5 is both a summary and a discussion of future work concerned with plasma-surface interactions in tandem mirrors.

Acoustic compressional and shear-wave velocities have been measured on a suite of ten sandstone samples obtained from wells in the Cerro Prieto geothermal field and on two rock samples from other Mexican geothermal fields. The samples were tested in both their dry and fully brine-saturated states at uniaxial stresses to 15 MPa. Electrical resistivities and associated phase angles have been measured on the same core samples as a function of frequency in the range 10 Hz to 10/sup 5/ Hz under drained conditions at hydrostatic confining stresses to 10 MPa. The electrical properties were measured on samples tested in their fully saturated state, using brines of two different concentrations.

Before small-angle neutron scattering (SANS), chain conformation studies were limited to light and small angle x-ray scattering techniques, usually in dilute solution. SANS from blends of normal and labeled molecules could give direct information on chain conformation in bulk polymers. Water-soluble polymers may be examined in H/sub 2/O/D/sub 2/O mixtures using contrast variation methods to provide further information on polymer structure. This paper reviews some of the information provided by this technique using examples of experiments performed at the National Center for Small-Angle Scattering Research (NCSASR).

Attendance at the workshop and information meeting on Cryogenics for the SSC held at Brookhaven National Laboratory on January 17 to 19, 1984 consisted of 109 engineers and scientists from 19 industrial organizations and 18 laboratories and universities - CERN, DESY, Grenoble, KEK and Saclay were represented. About one-third of the participants were from Brookhaven National Laboratory and Fermi National Laboratory. Talks which concentrated on informing the audience of the present status of the SSC research and development activities and progress towards design of the components were given, experience with the cryogenic system of the Tevatron was reported, and a wrap-up session was held on the last day where each of the five workshop leaders gave a summary of their group's discussions and conclusions. A brief summary of these presentations is given, with the detailed information gathered by the group leaders forming the bulk of these proceedings.

In this talk on magnetic monopoles, first the author briefly reviews some historical background; then, the author describes what several different types of monopoles might look like; and finally the author discusses the experimental situation. 81 references.

This volume represents the Proceedings of the Eighth International Colloquium on Ultraviolet and X-Ray Spectroscopy of Astrophysical and Laboratory Plasmas. The aim of this series of colloquia has been to bring together workers in the fields of astrophysical spectroscopy, laboratory spectroscopy and atomic physics in order to exchange ideas and results on problems which are common to these different disciplines. In addition to the presented papers there was a poster paper session. (WRF)

The Office of Energy Research was recently asked to perform a study of Large Scale Systems in order to facilitate the development of a true large systems theory. It was decided to ask experts in the fields of electrical engineering, chemical engineering and manufacturing/operations research for their ideas concerning large scale systems research. The author was asked to distribute a questionnaire among these experts to find out their opinions concerning recent accomplishments and future research directions in large scale systems research. He was also requested to convene a conference which included three experts in each area as panel members to discuss the general area of large scale systems research. The conference was held on March 26--27, 1984 in Pittsburgh with nine panel members, and 15 other attendees. The present report is a summary of the ideas presented and the recommendations proposed by the attendees.

Separate abstracts were prepared for individual papers. (MHR)