A field demonstration was funded by the US Department of Energy (DOE) to quantify the potential use of montan wax as a subsurface barrier material for nuclear waste management applications. As part of that demonstration, a study was completed to address some of the characteristics of the wax. Of particular interest is its resistance to chemical and structural changes that would influence its integrity as a barrier to minimize the migration of contaminants from their storage or disposal locations. Properties that were evaluated included hardness, melting point, molecular weight, and biodegradation as a function of gamma radiation dose. Based on the data obtained to date the wax is extremely resistant to radiation-induced change. Coupled with low permeability, the material shows promise as a subsurface barrier material.

In direct drive ICF, nonuniformities in laser illumination seed ripples at the ablation front in a process called imprint. These non nonuniformities grow during the capsule implosion and, if initially large enough, can penetrate the capsule shell, impede ignition, or degrade burn. Imprint has been simulated for recent experiments performed on the Nova laser at LLNL examining a variety of beam smoothing conditions. Most used laser intensities similar to the early part of an ignition capsule pulse shape, I=10X13 W/cm3. The simulations matched most of the measurements of imprint modulation. The effect of imprint upon National Ignition Facility (NIF) direct drive ignition capsules has also been simulated. Imprint is predicted to give modulation comparable to an intrinsic surface finish of 10 nm RMS. Modulation growth was examined using the Haan model, with linear growth as a function of spherical harmonic mode number obtained from an analytic dispersion relation. Ablation front amplitudes are predicted to become substantially nonlinear, so that saturation corrections are large. Direct numerical simulations of two- dimensional multimode growth were also performed. The capsule shell is predicted to remain intact, which gives a basis for believing that ignition can be achieved.

Experimental short pulse lasers are rapidly approaching energy levels where target irradiances exceeding 10{sup 20} W/CM{sup 2} are routinely achievable. These high intensity levels will open up a new class of solid target interaction physics where relativistic effects must be included and non-traditional absorption mechanisms become significant. However much remains to be understood of the absorption physics at lower intensities where classical absorption is dominated by collisional and resonance absorption. If attention is paid to producing clean laser pulses that do not significantly pre-pulse interact with the target, it is possible to produce plasmas of sufficiently short scale length that near-solid density interactions are observable at intensities exceeding 10{sup 18} W/CM{sup 2} for 100 fs laser irradiation. We report here extensions to our previous efforts at normal incidence that expand our observations to non-normal angles including the effect of polarization for several target materials. Between 10{sup 13} W/CM{sup 2} and 10{sup 14} W/CM{sup 2} we observe that the target absorption retains a signature of the intra-band atomic transitions. At higher intensities a more material independent ion-electron collisional absorption and short scale length resonance absorption dominate. P - polarized absorption in short scale length plasmas has been observed to exceed 60 …

Diffuse reflectance infrared spectroscopy is a very useful tool for the determination of surface contamination and characterization of films in manufacturing applications. Spectral data from the surfaces of a host of practical materials may be obtained with sufficient insensitivity to characterize relatively thick films, such as paint, and the potential exists to detect very thin films, such as trace oil contamination on metals. The SOC 400 Surface Inspection Machine/InfraRed (SIMIR) has been developed as a nondestructive inspection tool to exploit this potential in practical situations. This SIMIR is a complete and ruggidized Fourier transform infrared spectrometer with a very efficient and robust barrel ellipse diffuse reflectance optical collection system and operating software system. The SIMIR weighs less than 8 Kg, occupies less than 14 L volume, and may be manipulated into any orientation during operation. The surface to be inspected is placed at the focal point of the SIMIR by manipulating the SIMIR or the surface. The SIMIR may or may not contact the surface being inspected. For flat or convex items, there are no size limits to items being inspected. For concave surfaces, the SIMIR geometry limits the surface to those having a radius of curvature greater than 0.2 …

In this paper, we present a conceptual design for a general-purpose adaptive optics system, usable with all Cassegrain facility instruments on the 3 meter Shane telescope at the University of California`s Lick Observatory located on Mt. Hamilton near San Jose, California. The overall design goal for this system is to take the sodium-layer laser guide star adaptive optics technology out of the demonstration stage and to build a user-friendly astronomical tool. The emphasis will be on ease of calibration, improved stability and operational simplicity in order to allow the system to be run routinely by observatory staff. A prototype adaptive optics system and a 20 watt sodium-layer laser guide star system have already been built at Lawrence Livermore National Laboratory for use at Lick Observatory. The design presented in this paper is for a next- generation adaptive optics system that extends the capabilities of the prototype system into the visible with more degrees of freedom. When coupled with a laser guide star system that is upgraded to a power matching the new adaptive optics system, the combined system will produce diffraction-limited images for near-IR cameras. Atmospheric correction at wavelengths of 0.6-1 mm will significantly increase the throughput of the most …

One of the options for a design of a Central Solenoid in ITER and other tokamak machines is pancake would modules. In this configuration joints have to be placed in maximum magnetic field with high changing rate. In this condition joints should be designed to have at least the same or larger temperature margin as that for the conductor in the same field. It is argued that joints in parallel field can be designed to meet this requirement along with reasonably low DC resistance. Losses in parallel field are calculated and design features which can suppress AC losses without increasing DC resistance are discussed. Recommendations for low loss, low DC resistance joints are made.

A brief introductory overview in general terms is given of concepts, issues and applications of the paradigm of rugged landscapes in the contexts of physics and biology.

The magnetic phase diagrams of all dilute Cr alloys can be explained by a simple theoretical model with coupled spin- and charge-density waves and a finite electron reservoir. If the charge-density wave and electron reservoir are sufficiently large, the paramagnetic to commensurate spin-density wave transition becomes strongly first order, as found in Cr{sub 1- x}Fe{sub x} and Cr{sub 1-x}Si{sub x} alloys. The observed discontinuity of the slope dT{sub N}/dx at the triple point and the bending of the CI phase boundary are also natural consequences of this model.

The new, rapidly evolving field of industrial ecology - the objective, multidisciplinary study of industrial and economic systems and their linkages with fundamental natural systems - provides strong ground for believing that a more environmentally and economically efficient economy will be more information intensive and complex. Information and intellectual capital will be substituted for the more traditional inputs of materials and energy in producing a desirable, yet sustainable, quality of life. While at this point this remains a strong hypothesis, the evolution of the automobile industry can be used to illustrate how such substitution may, in fact, already be occurring in an environmentally and economically critical sector.

The Keck telescope adaptive optics system is designed to optimize performance in he 1 to 3 micron region of observation wavelengths (J, H, and K astronomical bands). The system uses a 249 degree of freedom deformable mirror, so that the interactuator spacing is 56 cm as mapped onto the 10 meter aperture. 56 cm is roughly equal to r0 at 1.4 microns, which implies the wavefront fitting error is 0.52 ({lambda}/2{pi})({ital d}/{ital r}{sub 0}){sup 5/6} = 118 nm rms. This is sufficient to produce a system Strehl of 0.74 at 1.4 microns if all other sources of error are negligible, which would be the case with a bright natural guidestar and very high control bandwidth. Other errors associated with the adaptive optics will however contribute to Strehl degradation, namely, servo bandwidth error due to inability to reject all temporal frequencies of the aberrated wavefront, wavefront measurement error due to finite signal-to-noise ratio in the wavefront sensor, and, in the case of a laser guidestar, the so-called cone effect where rays from the guidestar beacon fail to sample some of the upper atmosphere turbulence. Cone effect is mitigated considerably by the use of the very high altitude sodium laser guidestar (90 …

The All-Russian Scientific Research Institute of Inorganic Materials (VNIINM) performs research in nuclear power reactor fuel,m spent fuel reprocessing and waste management, materials science of fissionable and reactor structural materials, metallurgy, superconducting materials, and analytical sciences. VNIINM supports the Ministry of Atomic Energy of the Russian Federation (MINATOM) in technologies for fabrication and processing of nuclear fuel. As a participant in the U. S./Russian Lab-to-Lab nuclear materials protection, control and accounting (MPC&A) program, VNIINM is providing evaluation, certification, and implementation of measurement methods for such materials. In 1966, VNIINM will be working with Brookhaven staff in developing and documenting material control and accounting requirements for nuclear materials in bulk form, Livermore and Los Alamos staff in testing and evaluating gamma-ray spectrometry methods for bulk materials, Los Alamos staff in test and evaluation of neutron-coincidence counting techniques, Oak Ridge staff in accounting of bulk materials with process instrumentation, and Pacific Northwest staff on automating VNIINM`s coulometric titration system. In addition, VNIINM will develop a computerized accounting system for nuclear material within VNIINM and heir storage facility. This paper describes the status of this work and anticipated progress in 1996.

Although the unconventional nature of the superconductivity in pure and doped UBe{sub 13} has been well established, the precise nature of the superconducting order parameter is still unknown. The authors present muon spin rotation measurements in boron-doped UBe{sub 13} showing a paramagnetic frequency shift below the superconducting transition temperature which is nearly independent of applied magnetic field (0.01--0.10 T), unlike a conventional Knight shift. No increase in linewidth is observed in zero field. These results are compared to observations of the paramagnetic Meissner effect in other superconductors, and are discussed in terms of the possible alignment of orbital moments associated with unconventional superconductivity in this system.

Thomson scattering measurements of the electron temperature in laser- produced gold plasmas are presented. We irradiated a flat gold disk target with one laser beam of the Nova laser facility. A second laser beam probed the plasma at a distance of 500{mu}m with temporally resolved Thomson scattering. The electron temperature measurements are compared with hydrodynamic simulations using the code LASNEX for experiments applying smoothed and unsmoothed heater beams. In case of an unsmoothed heater beam the simulations predict temperatures which are about 40% higher than our measured data. Although the agreement is improved for a smoothed heater beam, discrepancies exist in the decay phase of the plasma. We discuss possible explanations for these observations.

Amorphous carbon films approximately 20 nm thick are used throughout the computer industry as protective coatings on magnetic storage disks. As storage densities increase, the role of the overcoat becomes increasingly important because of smaller spacings between the recording head and the spinning disk. Furthermore, future-generation disks call for an overcoat thickness of 5 nm or less. These small length scales and the high speed of the spinning disk (10-30 m/s) suggest that a molecular dynamics (MD) model might provide useful insight into friction and wear mechanisms when the head and disk make contact. One of the necessary inputs required to carry out such an MD model is a specification of the position of all the atoms in the simulation, i.e. a detailed model of the material microstructure. Such a detailed understanding of the microstructure of amorphous carbon overcoats does not presently exist. Neutron and electron diffraction studies demonstrate that the material is amorphous. Previous classical MD simulations yield pair distribution functions in qualitative agreement with the diffraction studies, but they all differ in detail. More recent, quantum-mechanical tight-binding MD (TBMD) studies give a better description of the interatomic interactions and the chemical hybridization (sp{sup 2}-graphite-like versus sp{sup 3}-diamond-like). However, …

{open_quotes}Gist{close_quotes} is a scientific graphics library written by David H. Munro of Lawrence Livermore National Laboratory (LLNL). It features support for three common graphics output devices: X Windows, (Color) PostScript, and ANSI/ISO Standard Computer Graphics Metafiles (CGM). The library is small (written directly to Xlib), portable, efficient, and full-featured. It produces X versus Y plots with {open_quotes}good{close_quotes} tick marks and tick labels, 2-dimensional quadrilateral mesh plots with contours, vector fields, or pseudo color maps on such meshes, with 3-dimensional plots on the way. The Python Gist module utilizes the new {open_quotes}Numeric{close_quotes} module due to J. Hugunin and others. It is therefore fast and able to handle large datasets. The Gist module includes an X Windows event dispatcher which can be dynamically added (e.g., via importing a dynamically loaded module) to the Python interpreter after a simple two-line modification to the Python core. This makes fast mouse-controlled zoom, pan, and other graphic operations available to the researcher while maintaining the usual Python command-line interface. Munro`s Gist library is already freely available. The Python Gist module is currently under review and is also expected to qualify for unlimited release.

Older single-story facilities (Pre-1985 vintage) are commonly constructed of structural steel framing with concrete masonry unit (CMU) walls connected to columns and roof girders of the steel framing system. The CMU walls are designed for lateral wind and seismic loads (perpendicular to the wall) and transmit shear loads from the roof diaphragm to the foundation footings. The lateral loads normally govern their design. The structural framing system and the roof diaphragm system are straight forward when analyzing or upgrading the structure for NPH loads. Because of a buildings design vintage, probable use of empirical methodology, and poor design basis documentation (and record retention); it is difficult to qualify or upgrade CMU walls for lateral Natural Phenomena Hazards (NPH) loads in accordance with References 1, 2 and 3. This paper discusses three analytical approaches and/or techniques (empirical, working stress and yield line) to determine the collapse capacity of a laterally loaded CMU wall, and compares their results

These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. Effective chiral models such as the linear and nonlinear sigma model will be discussed as well as the essential ideas of chiral perturbation theory. Some applications to the physics of ultrarelativistic heavy ion collisions will be presented.

Adaptive optics on the Keck 10 meter telescope will provide an unprecedented level of capability in high resolution ground based astronomical imaging. The system is designed to provide near diffraction limited imaging performance with Strehl {gt} 0.3 n median Keck seeing of r0 = 25 cm, T =10 msec at 500 nm wavelength. The system will be equipped with a 20 watt sodium laser guide star to provide nearly full sky coverage. The wavefront control subsystem is responsible for wavefront sensing and the control of the tip-tilt and deformable mirrors which actively correct atmospheric turbulence. The spatial sampling interval for the wavefront sensor and deformable mirror is de=0.56 m which gives us 349 actuators and 244 subapertures. This paper summarizes the wavefront control system and discusses particular issues in designing a wavefront controller for the Keck telescope.

Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the standard model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the standard model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed.

Fifty nanosecond pulses of visible light have been used to produce hard, hydrogen-free diamond-like-carbon (DLC) films at irradiances between 5 x 10{sup 8} and 5 x 10{sup 10} W/cm{sup 2} The films were characterized by a number of techniques including: Raman spectroscopy, Electron Energy Loss Spectroscopy (EELS), atomic force microscopy, and spectroscopic ellipsometry. The cost for manufacturing DLC with high average power, high-pulse repetition frequency, visible light is low enough to compete with other diamond thin film production methods.