The data-driven principles of execution present an elegant solution to the problem of instruction scheduling in large scale multiprocessor systems. However, much overhead must be expanded in detecting the simplest forms of parallelism such as vector operations. A two-level architecture with powerful processors is presented here. In addition, preemptive execution of certain actors allows better pipelining and tolerance to latencies. The natural application of the machine to numerical computations is demonstrated by the use of a multi-grid Partial Differential Equation solver.

The workshop was organized in order to address technological issues important to decisions regarding the feasibility of strategic options. The objectives of the workshop were to establish the current technological capabilities for deep-underground construction, to project those capabilities through the compressed schedule proposed for construction, and to identify promising directions for timely allocation of existing research and development resources. The earth has been used as a means of protection and safekeeping for many centuries. Recently, the thickness of the earth cover required for this purpose has been extended to the 2,000- to 3,000-ft range in structures contemplated for nuclear-waste disposal, energy storage, and strategic systems. For defensive missile basing, it is now perceived that the magnitude of the threat has increased through better delivery systems, larger payloads, and variable tactics of attack. Thus, depths of 3,000 to 8,000 ft are being considered seriously for such facilities. Moreover, it appears desirable that the facilities be operational (if not totally complete) for defensive purposes within a five-year construction schedule. Deep excavations such as mines are similar in many respects to nearsurface tunnels and caverns for transit, rail, sewer, water, hydroelectric, and highway projects. But the differences that do exist are significant. Major …

Objective of this task is to measure and characterize the ceramic properties (crystalline phase composition, grain boundaries, residual stresses) of a series of standard ceramic specimens to assist in developing international standards for ceramic characterization. This report describes electron microscopy of the microstructure and grain boundaries of ESK silicon carbide; supporting x-ray diffraction data for the bulk phase composition is included.

Microscopes based on soft X-ray lasers possess unique advantages in bridging the gap between high resolution electron microscopy of dehydrated, stained cells and light microscopy at comparatively low resolution of unaltered live cells. The high brightness and short pulse duration of soft X-ray lasers make them ideal for flash imaging of live specimens. The Princeton soft X-ray laser is based on a magnetically confined laser produced carbon plasma. Radiation cooling after the laser pulse produces rapid recombination which produces a population inversion and high gain. A full account is given in a companion paper in this volume. The important characteristics of the laser beam produced by this device are 1 to 3 mJ of 18.2 nm radiation in a 10 to 30 nsec pulse with a divergence of 5 mrad. The 18.2 nm wavelength, while outside the water window, does provide a factor of 3 difference in absorption coefficients between oxygen and carbon.

Over the last few years there has been a significant increase in the use of radionuclides in leukocyte, platelet, and erythrocyte imaging procedures. Radiopharmaceutical used in these procedures are confined primarily to the blood, have short half-lives, and irradiate the body as they move through the circulatory system. There is a need for a model, to describe the circulatory system in an adult human, which can be used to provide radiation absorbed dose estimates for these procedures. A simplified model has been designed assuming a static circulatory system and including major organs of the body. The model has been incorporated into the MIRD phantom and calculations have been completed for a number of exposure situations and radionuclides of clinical importance. The model will be discussed in detail and results of calculations using this model will be presented.

Aqueous suspensions of charged polymer latex particles exhibit several forms of ordered structure, the particular form depending on the size, number density and charge of the latex particles, and on the ionic strength of the aqueous medium. At low ionic strength, the inter-particle potential may become sufficiently long-ranged to generate crystalline order, which usually shows bcc symmetry at low density and becomes fcc above about 3% volume fraction of latex in the system. As the ionic strength increases, the crystalline structure melts, and ordered liquid structures develop. This paper reviews some of the recent small-angle neutron scattering experiments on polymer latex suspensions, in the light of new theoretical methods which permit in situ analysis of the particle size and charge. The discussion also encompasses new experimental methods for studying latex structures under dynamic shear conditions.

We report some of the latest developments in x-ray holography experiments and make some speculations about the limits of performance of the approaches currently in use. We also make some suggestions about where the technique can (and cannot) go in the future. 32 refs., 5 figs., 1 tab.

Neutron energy spectra, fluence distributions and rates in the FNAL Tevatron tunnel are summarized. This work has application to radiation damage to electronics and research equipment at high energy accelerators, as well as to radiological protection. 7 refs., 4 figs.

This paper contains articles on semiconductor devices used in the detection of high energy particles. Some articles reported: Position sensitive semiconductor devices; Scintillation techniques and optical devices; Radiation damage to detectors; VLSI for physics; and experience with Si detectors in NA32. (LSP)

We are searching for a new second- and third-harmonic generators among the salts of chiral organic acids and bases. We discuss the relevant properties of crystals from this group of compounds, including their nonlinear and phasematching characteristics, linear absorption, damage threshold and crystal growth. In addition, we summarize what is known concerning other nonlinear optical properties of these crystals, such as two-photon absorption, nonlinear refractive index, and stimulated Raman thresholds. A preliminary assessment is made of the potential of these materials for use in future high power, large aperture lasers such as those used for inertial confinement fusion experiments. 14 refs., 1 fig., 3 tabs.

Results from a data base search of computerized nuclear structure libraries have been extended and augmented so as to expand the information available for nuclei suitable as gamma-ray laser candidates. The spectrum of nuclear levels occurring in deformed rotational nuclei have been calculated and have been used in conjunction with isomeric state data for odd-A systems. The results of this augmentation effort are presented with particular emphasis on results obtained for /sup 177/Lu, /sup 177/Hf, and /sup 179/Hf. For these cases some possibly interesting cases were identified that met energy spacing criteria. However, significant hindrance factors exist for them which negate their interest for gamma-ray laser applications. 9 refs., 1 fig., 1 tab.

Three Dimension Nuclear Hartree-Fock calculations have been performed for isotopes of Osmium, Mercury, and Tungsten. Many of the calculated potential energy surfaces show a second minimum at large prolate deformation indicating the possibility of shape isomeric states. Several are at sufficiently low energy to be possible candidates as storage states for the gamma ray laser. 9 refs., 4 figs., 1 tab.

Fusion, the process that powers our sun, has long promised to be a virtually inexhaustible source of energy for mankind. No other alternative energy source holds such bright promise, and none has ever presentd such formidable scientific and engineering challenges. Serious research efforts have continued for over 30 years in an attempt to harness and control fusion here on earth. Scientists have made considerable progress in the last decade toward achieving the conditions required for fusion power, and recent experimental results and technological progress have made the scientific feasibility of fusion a virtual certainty. With this knowledge and confidence, the emphasis can now shift toward developing power plants that are practical and economical. Although the necessary technology is not in hand today, the extension to an energy producing system in 20 years is just as attainable as was putting a man on the moon. In the next few decades, the world's population will likely double while the demand for energy will nearly quadruple. Realistic projections show that within the next generation a significant fraction of our electric power must come from alternative energy sources. Increasing environmental concerns may further accelerate this timetable in which new energy sources must be introduced. …

The conference included papers on facility plans, beam dynamics, accelerator hardware, and experimental facilities. Individual abstracts were prepared for 43 papers in the conference proceedings. (LEW)

Leukemia patients typically have low granulocyte counts as do those with aplastic anemia. A review of the literature on these latter patients quickly indicates that they live much longer than leukemic patients with the same counts. To check this numerically, the survival times for 12 aplastic anemia patients reported in 1934 were compared with the expected survival times for more recent patients using methods employed to compute the probabilities. On the average, the aplastic anemia patients lived almost ten times as long as the leukemia patients would have been expected to live. 5 refs., 2 figs.

This paper presents recent results from the Mark III detector at SPEAR, in the open charm sector. The first topic discussed is the reanalysis of the direct measurement of the D hadronic branching fractions, where a detailed study has been made of the Cabibbo suppressed and multi-..pi../sup 0/'s D decays backgrounds in the double tag sample. Next, the Dalitz plot analysis of the D decays to K..pi pi.. is presented, leading to the relative fractions of three-body versus pseudoscalarvector decays. 7 refs., 5 figs.

Controlled fusion, pursued by investigators in both the magnetic and inertial confinement research programs, continues to be a strong candidate as an intrinsically safe and virtually inexhaustible long-term energy source. We describe the status of magnetic and inertial confinement fusion in terms of the accomplishments made by the research programs for each concept. The improvement in plasma parameters (most frequently discussed in terms of the Tn tau product of ion temperature, T, density, n, and confinement time, tau) can be linked with the construction and operation of experimental facilities. The scientific progress exhibited by larger scale fusion experiments within the US, such as Princeton Plasma Physics Laboratory's Fusion Test Reactor for magnetic studies and Lawrence Livermore National Laboratory's Nova laser for inertial studies, has been optimized by the theoretical advances in plasma and computational physics. Both TFTR and Nova have exhibited ion temperatures in excess of 10 keV at confinement parameters of n tau near 10/sup 13/ cm/sup -3/ . sec. At slightly lower temperatures (near a few keV), the value of n tau has exceeded 10/sup 14/ cm/sup -3/ . sec in both devices. Near-term development plans in fusion research include experiments within the US, Europe, and Japan to …

A multidisciplinary team of Los Alamos scientists, supported by the US Department of Energy, has been developing the requisite technologies to extend free-electron laser (FEL) operation from infrared and visible wavelengths into the extreme-ultraviolet below 100 nm using rf-linear accelerator technology. The goal is to establish an XUV Free-Electron Laser User Facility, the next-generation light source that will make available to researchers optical power more than one-million times greater than provided by synchroton light sources. Based primarily on a series of FEL oscillators driven by a single, rf-linac, the Los Alamos facility is designed to generate broadly tunable, picosecond-pulse, coherent radiation spanning the soft x-ray through the ultraviolet to the visible spectral ranges from 1 nm to 400 nm. The FEL facility design is discussed and performance predicted. 3 figs., 5 tabs.

The yield of singly- and multiply- charged ions of krypton and xenon is presented as a function of laser intensity and frequency. The measurements were performed using the second harmonic output of a well-characterized, tunable picosecond dye laser in the range 285 to 310 nm at laser intensities from 1 x 10/sup 12/ to 10/sup 14/ W/cm/sup 2/. Enhancement of the Kr/sup +/ yield by two orders of magnitude by three-photon resonant, four-photon ionization is observed in the vicinity of the 4d'(5/2)/sub 3/ and the 4d(3/2)/sub 1/ intermediate states. A model incorporating line shifts and widths scaling linearly with intensity is in good agreement with the experimental results.

Due to rapid improvements in high-power laser performance, two-photon absorption processes have become a very useful tool for studying the molecular structures of various gases, liquids and solids. However, measurements of absolute two-photon absorption cross sections were more or less ignored previously because of their small size. In this work, we obtained not only the two-photon absorption spectra, but also measurements of their absolute cross sections for various gases, liquids, and solids. 8 refs., 1 fig., 1 tab.

A study of the Pomeron in QCD is briefly outlined. Implications for the production of W/sup +/W/sup -/ and Z/sup 0/Z/sup 0/ pairs are described and the possibility that the electroweak scale is a major strong-interaction threshold discussed. The application of Pomeron phase-transition theory to SU(5) dynamical symmetry breaking is suggested and the related ''strong-interaction'' properties of the photon briefly mentioned.

Two photon spectroscopy of argon, krypton and molecular hydrogen is considered in this paper. Experimental transition energies and two-photon rate constants are given. 4 refs., 1 tab. (LSP)

Experiments measuring the movement of trace amounts of radionuclides through compacted bentonite have typically used unaltered bentonite. Models based on experiments such as these may not lead to accurate predictions of the migration through altered or partially altered bentonite of radionuclides that undergo ion exchange. To address this problem, we have modified an existing transport code to include ion exchange and aqueous complexation reactions. The code is thus able to simulate the diffusion of major ionic groundwater components through bentonite and reactions between the bentonite and groundwater. Numerical simulations have been made to investigate the conversion of sodium bentonite to calcium bentonite for a reference groundwater characteristic of deep granitic formations. 20 refs., 2 figs., 2 tabs.

This paper summarizes recent progress in the understanding of energetic displacement cascades and the primary state of damage in metals. On the theoretical side, the availability of supercomputers has greatly enhanced our ability to simulate cascades by molecular dynamics. Recent application of this simulation technique to Cu and Ni provides new insight into the dynamics of cascade processes. On the experimental side, new data on ion beam mixing and in situ electron microscopy studies of ion damage at low temperatures reveal the role of the thermodynamic properties of the material on cascade dynamics and structure. 38 refs., 9 figs.