Magnetically driven imploding liner systems can be used as a source of shock energy for materials equation of state studies, implosion driven magnetized plasma fusion experiments, and other similar applications. The imploding liner is a cylinder of conducting material through which a current is passed in the longitudinal direction. Interaction of the current with its own magnetic field causes the liner to implode. Sources of electrical energy for imploding liner systems are capacitor banks or explosive pulse power systems seeded by capacitor banks. In August, 1996, a high energy liner experiment (HEL-1) was conducted at the All-Russia Scientific Research Institute (VNIIEF) in Sarov, Russia. A 5 tier 1 meter diameter explosive disk generator provided electrical energy to drive a 48 cm outside diameter, 4 mm thick, aluminum alloy liner having a mass of about 11kg onto an 11 cm diameter diagnostic package. The purpose of the experiment was to measure performance of the explosive pulse power generator and the heavy imploding liner. Electrical performance diagnostics included inductive (B-dot) probes, Faraday Rotation current measurement, Rogowski total current measurement, and voltage probes. Flux loss and conductor motion diagnostics included current-joint voltage measurements and motion sensing contact pins. Optical and electrical impact pins, …

Austenitic 316LN alloy was ion-irradiated using the unique Triple Ion Beam Facility (TIF) at ORNL to investigate radiation damage effects relevant to spallation neutron sources. The TIF was used to simulate significant features of GeV proton irradiation effects in spallation neutron source target materials by producing displacement damage while simultaneously injecting helium and hydrogen at appropriately high gas/dpa ratios. Irradiations were carried out at 80, 200, and 350 C using 3.5 MeV Fe{sup ++}, 360 keV He{sup +}, and 180 keV H{sup +} to accumulate 50 dpa by Fe, 10,000 appm of He, and 50,000 appm of H. Irradiations were also carried out at 200 C in single and dual ion beam modes. The specific ion energies were chosen to maximize the damage and the gas accumulation at a depth of {approximately} 1 {micro}m. Variations in microstructure and hardness of irradiated specimens were studied using transmission electron microscopy (TEM) and a nanoindentation technique, respectively. TEM investigation yielded varying damage defect microstructures, comprising black dots, faulted and unfaulted loops, and a high number density of fine bubbles (typically less than 1 nm in diameter). With increasing temperature, faulted loops had a tendency to unfault, and bubble microstructure changed from a bimodal …

High current photocathodes operating in vacuum environments as high as 8xE-5 torr are being developed at Los Alamos for use in a new generation of linear induction accelerators. We report quantum efficiencies in wide bandgap semiconductors, pure metals, and compound metal surfaces photocathode materials illuminated by ultraviolet laser radiation.

Dose measurements made on and around the insertion devices (IDs) at the Advanced Photon Source are reported. Attempts are made to compare these dose rates to dose rates that have been reported to cause radiation-induced demagnetization, but comparisons are complicated by such factors as the particular magnet material and the techniques used in its manufacture, the spectrum and type of radiation, and the demagnetizing field seen by the magnet. The spectrum of radiation at the IDs. It has almost no effect on the dose to the downstream ends of the IDs, however, since much of the radiation travels through the ID vacuum chamber and cannot be readily shielded. Opening the gaps of the IDs during injection and at other times also helps decrease the radiation exposure.

Electron synchrotron storage rings, such as the VUV ring at the National Synchrotron Light Source (NSLS), produce short pulses of infrared (IR) radiation suitable for investigating the time-dependent phenomena in a variety of interesting experimental systems. In contrast to other pulses sources of IR, the synchrotron produces a continuum spectral output over the entire IR (and beyond), though at power levels typically below those obtained from laser systems. The infrared synchrotron radiation (IRSR) source is therefore well-suited as a probe using standard FTIR spectroscopic techniques. Here the authors describe the pump-probe spectroscopy facility being established at the NSLS and demonstrate the technique by measuring the photocarrier decay in a semiconductor.

The United States Department of Energy is presently faced with the stabilization and safe disposition of hundreds of metric tons of residue materials resulting from 50+ years of nuclear weapons production activities. These residues encompass a broad range of substrates and radionuclides and include both solid and liquid materials. Combustible residues constitute a significant fraction of the total residue inventory, and an important constituent within the combustible category is spent anion ion-exchange resins. These resins are typically utilized for the separation of plutonium from other radionuclides under strongly acidic nitric or hydrochloric acid solution conditions which favor the formation and partitioning of anionic Pu(IV) nitrato or chloride species. The spent resins are usually rinsed prior to storage as residues to reduce both acid and radionuclide concentrations, but significant radionuclide concentrations remain in these resins, and the long-term effects of concentrated acid and radiolysis on the resin integrity are relatively unexplored. Thus, new research is needed to assess the stability of these resin residues and address the need for further treatment to ensure stability prior to long-term disposal.

Since August of 1994, the Los Alamos National Laboratory has been using the LANL Categorization Criteria Matrix for determining the need for and level of reporting criticality safety limit violations. The LANL Categorization Criteria Matrix is DOE approved, and is cited in a DOE approved SAR for the LANL Plutonium Facility as the method used to determine whether a criticality limit violation is reportable to DOE via 5000.3B ``Occurrence Categorization, notification and Reporting Requirements`` (replaced by DOE O 232.1). The use of the LANL Categorization Criteria Matrix provides a framework that allows criticality limit violations to be objectively reviewed in terms of what were the consequences of the criticality safety limit violation. Using the LANL Categorization Criteria Matrix helps the criticality safety engineer and line supervision explain to others, in a quantifiable manner, the significance of the criticality limit violation, the levels of margin of safety built into operations, and demonstrate the difference between evaluated conditions and working conditions.

Fiber microbuckling is the primary failure mechanism in unidirectional fiber-reinforced composites under compression. Due to processing or service conditions, damage (e.g., microcracks) exists at fiber/matrix interfaces. The effect of damage on the microbuckling of fibers is investigated in the present study. Based on the micromechanics analysis, the damage at interfaces is modeled as a linear spring against interface sliding, and the spring constant depends on the damage level. It is established that the critical strain for fiber microbuckling is relatively insensitive to the interface damage, but increases rapidly with the fiber volume fraction.

Simulation of the complete response of components and systems composed of energetic materials, such as PBX-9501 is important in the determination of the safety of various explosive systems. For example, predicting the correct state of stress, rate of deformation and temperature during penetration is essential in the prediction of ignition. Such simulation requires accurate constitutive models. These models must also be computationally efficient to enable analysis of large scale three dimensional problems using explicit lagrangian finite element codes such as DYNA3D. However, to be of maximum utility, these predictions must be validated against robust dynamic experiments. In this paper, the authors report comparisons between experimental and predicted displacement fields in PBX-9501 during dynamic deformation, and describe the modeling approach. The predictions used Visco-SCRAM and the Generalized Method of Cells which have been implemented into DYNA3D. The experimental data were obtained using laser-induced fluorescence speckle photography. Results from this study have lead to more accurate models and have also guided further experimental work.

To reconstruct (approximate) an arbitrary surface using subsurfaces (patches) from a library of surfaces in an optimal way is an interesting algorithmic problem and has many applications in image processing. This paper presents an efficient algorithm for an optimal reconstruction of a query surface using patches from a reference library of surfaces, under the constraint that the smallest patch size is above some specified value. In this algorithm, a surface is given as an integer function f(x, y) over a finite 2-D grid. The algorithm partitions a query surface into patches in such a way that each patch is represented by a similar patch from a library surface, and the total difference between the query surface and the representing (composite) surface is minimized, where the boundary of a patch is not pre-determined but solely determined by the optimization process. By using a minimum spanning tree-based data structure, this optimization problem can be solved efficiently. An application of this technique in computational forensics is outlined.

Coincidence cross sections for (e, e{prime}p) quasi-elastic scattering were measured at CEBAF with high statistical precision for C, Fe, and Au targets for 0.6 < Q{sup 2} < 3.3 GeV{sup 2}. Missing energy and missing momentum distributions obtained from a preliminary analysis are in reasonable agreement with prior data from SLAC. The preliminary analysis are compared with a PWIA calculation to determine the nuclear transparency as a function of Q{sup 2} and A. A Rosenbluth analysis to extract the longitudinal and transverse cross sections from these data is anticipated.

The authors search for the Flavor-Changing Neutral Current decays of the top quark t {yields} q{gamma} and t {yields} qZ (here q represents the c and u quarks) in p{bar p} collisions at {radical}s = 1.8 TeV from a dataset with an integrated luminosity of approximately 110 pb{sup {minus}1} collected during the 1992-1995 run of the Collider Detector at Fermilab. They set limits on the branching fractions BF (t {yields} q{gamma}) < 2.9% (at 95% CL) and BF (t {yields} qZ) < 44% (at 90% CL), consistent with the Standard Model.

The nuclear industry of Ukraine is a vital part of the national economy. In 1995 nuclear power accounted for approximately 37% of the total electricity production. Ukraine has five nuclear power stations with fourteen reactors in commercial operation. Ukraine also has research facilities whose work involves nuclear materials. Improving the security of the nuclear material under its control is an important goal for the Ukrainian nuclear community. Ukraine has requested and is receiving the assistance of several IAEA member states in material protection, control and accounting (MPC and A). The US DOE is providing assistance in nuclear material safeguards in both material control and accountability (MC and A) and physical protection (PP) to the national regulatory authority and to four facilities in Ukraine. The program is well under way. At the Kiev Institute of Nuclear Research (KINR) a significant upgrade of the PP system has been completed. Similar upgrades are in progress at the Kharkov Institute of Physics and Technology (KIPT), South Ukraine Nuclear Power Plant (SUNPP) and Sevastopol Institute of Nuclear Energy and Industry (SINEI). MC and A equipment and software, including computers and NDA instrumentation, have been delivered to the facilities. This paper summarizes accomplishments of the program …

Argonne National Laboratory (ANL) is developing chemically bonded phosphate ceramics (CBPCs) to treat low-level mixed wastes, particularly those containing volatiles and pyrophorics that cannot be treated by conventional thermal processes. This work was begun under ANL`s Laboratory Directed Research and Development funds, followed by further development with support from EM-50`s Mixed Waste Focus Area.

A significant effort within the Department of Energy`s Office of Transportation Technologies and the U.S. Navy`s Power Electronic Building Block (PEBB) project has focused on reducing the size and weight of power electronic devices for electric and hybrid vehicles. Power electronic circuits, which are composed of active switching elements and passive components such as capacitors and inductors, provide motor control, power distribution, and DC/AC conversion functions in electric vehicles. Progress has been made on reducing the size and weight of power electronic components such as MOS-controlled thristors and insulated-gate bipolar transistors. Additional effort on high-power capacitors will be needed for load leveling and filter functions. The objective of this work is to fabricate a new class of high-power capacitors with reduced size and weight. Capacitors will be integrated with semiconductor components of electric motor and actuator control subsystems.

The pyrochemical conditioning of spent nuclear fuel for the purpose of final disposal is currently being demonstrated at Argonne National Laboratory (ANL). One aspect of this program is to develop a lithium preprocessing stage for the Fuel Conditioning Facility (FCF). Furthermore, a pilot scale of this preprocessing stage is being designed by ANL-W to demonstrate the in situ hot cell capability of this process. In this pilot scale system, fused lithium chloride salt is saturated with molten lithium to form a powerful fluxing compound with a vigorous reducing agent. During this stage of the fuel conditioning, the reduction will take place at a nominal temperature of 650 C in an argon-cell atmosphere contaminated with up to 10,000 ppm nitrogen, 100 ppm oxygen and 100 ppm of moisture. The maximum local temperature was calculated to be 725 C on the inner shell of the reduction vessel during operation. One of the significant concerns of this project is the system`s corrosion response in the presence of irradiated commercial fuel as well as atmospheric impurities. The purpose of this work was to demonstrate the potential corrosivity of the salt matrix in a worse case environment as well as provide a boundary for allowable …

Interest in critical experiments with lattices of mixed-oxide (MOX) fuel pins has been revived by the possibility that light water reactors will be used for disposition of weapons-grade plutonium. A series of six experiments with MOX lattices, designated PNL-30 through PNL-35, was performed at Pacific Northwest Laboratories in 1975 and 1976, and a set of benchmark specifications for these experiments subsequently was adopted by the Cross Section Evaluation Working Group (CSEWG). Although there appear to be some problems with these experiments, they remain the only CSEWG benchmarks for MOX lattices. The number of fuel pins in these experiments is relatively low, corresponding to fewer than 4 typical pressurized-water-reactor fuel assemblies. Accordingly, they are more appropriate as benchmarks for lattice-physics codes than for reactor-core simulator codes. Unfortunately, the CSEWG specifications retain the full three-dimensional (3D) detail of the experiments, while lattice-physics codes almost universally are limited to two dimensions (2D). This paper proposes an extension of the benchmark specifications to include a 2D model, and it justifies that extension by comparing results from the MCNP Monte Carlo code for the 2D and 3D specifications.

The results of an analysis of operations data from the 1996 run-cycle of the LANSCE accelerator complex will be presented. Frequency and history of operational events including system and component failures which affect beam availability have been tracked. Some of the significant downtime incidents will be described and analyzed in detail. These results will be used to improve future operations and beam availability.

A new 14 GHz ECRIS has been designed and built over the last two years. The source design incorporates the latest results from ECR developments to produce intense beams of highly charged ions. An improved magnetic electron confinement is achieved from a large mirror ratio and strong hexapole field. The aluminum plasma chamber and extraction electrode as well as a biased disk on axis at the microwave injection side donate additional electrons to the plasma, making use of the large secondary electron yields from aluminum oxide. The source will be capable of ECR plasma heating using two different frequencies simultaneously to increase the electron energy gain. To be able to deliver usable intensities of the heaviest ion beams the design will also allow axial access for metal evaporation ovens and solid material. The main design goal is to produce several e{mu}A of at least {sup 238}U{sup 34+} in order to accelerate the beam to coulomb-barrier energies without further stripping. First charge state distributions for {sup 16}O and {sup 40}Ar have been measured.

Over the last few years, there has been a resurgence of interest in small-x or diffractive physics. This has been due to the realization that perturbative QCD techniques may be applicable to what was previously thought of as a non-perturbative problem and to the opening up of new energy regimes at HERA and the Tevatron collider. The goal is to understand the pomeron, and hence the behavior of total cross sections, elastic scattering and diffractive excitation, in terms of the underlying theory, QCD. This paper is divided into experiments of hadron-hadron colliders and electron-proton colliders.

The particle size distribution and morphology of HMX (cyclotetramethylene-tetranitramine) in the plastic-bonded explosive, PBX 9501 (95% HMX and 5% polymeric binder, by weight), are important to understanding the micromechanical behavior of this material. This paper shows that the size distribution of the {open_quotes}as-received{close_quotes} HMX powder, as measured by light scattering, is not preserved through the processing operations of formulation into molding powder and subsequent consolidation through hydrostatic pressing. Morphological features such as cracking and twinning are examined using reflected light microscopy. This technique helps confirm and interpret the results of the particle size analysis. These results suggest that use of the particle size distribution of the {open_quotes}as-received{close_quotes} powder could potentially yield significant errors in detailed simulations of formulated materials.

The authors have exploited anomalous small angle x-ray scattering (ASAXS) to monitor the solvation behavior of Cu(II), Er(III) and Yb(III) ions within the interlayers of the natural aluminosilicate clay mineral montmorillonite. The ASAXS technique can reveal the distribution of specific metallic species within a heterogeneous and disordered matrix. The variations of signal intensity as a function of absorption energy were monitored for all of the metal-clays as a function of hydration. Two different hydration levels were probed: as prepared at ambient conditions, or so-called {open_quotes}dry{close_quotes} powders, and {open_quotes}wet{close_quotes} pastes. ASAXS intensities should increase with absorption energy if the metal ion is associated with the interlayer solvent (water in this case), and decrease if the metal ion is associated with the solid matrix. The results show that: (1) Cu(II) is solvated within the interlayers of the wet sample, as expected, and (2) Er(III) and Yb(III) decrease in ASAXS intensity with increased hydration. This latter result was not expected and there is speculation that these ions have associated as hydrolyzed products with the clay surface. The basic principles underlying SAXS and ASAXS will also be presented in this paper.

Coulomb dissociation is a relatively clean probe of the structures of one- and two-nucleon halo nuclei. This is illustrated by the breakup of {sup 11}Be, {sup 8}B and {sup 11}Li and is discussed in terms of first order perturbation theory. First-order dipole transitions usually dominate the Coulomb dissociation but quadrupole transitions are not insignificant for a proton halo (e.g. {sup 8}B). Higher-order processes can also distort the observables, such as the momentum distributions of the fragments and the excitation energy spectrum.

The H-mode power threshold has a weak but positive B{sub T} dependence when the ion {del}B drift is away from the X-point, in contrast to the nearly linear B{sub T} dependence when the ion {del}B drift is toward the X-point. This indicates that geometry plays an important role in the H-mode power threshold scaling. A simple model of the {del}B drift effect failed to predict this behavior, but successfully predicted the sign change of gas puffing and low X-point height on the power threshold. The difference between the threshold power required for sawtooth and nonsawtooth triggered transitions can be substantial. This effect may contribute to the observed B scaling of the H-mode power threshold.