Significantly different radiation responses have been observed for both transistors and ICs with and without preirradiation burn-in. The hardness assurance implications of these results and possible changes to the MIL-STDs will be presented.
A well-controlled, high-yield Josephson junction process in high temperature superconductors (HTS) is necessary for the demonstration of ultra-high-speed devices and circuits which exceed the capabilities of conventional electronics. The authors developed nanobridge Josephson junctions in high quality thin-film YBaCuO with dimensions below 100 nm fabricated using electron-beam nanolithography. They characterized this Josephson junction technology for process yield, junction parameter uniformity, and overall applicability for use in high-performance circuits. To facilitate the determination of junction parameters, they developed a measurement technique based on spectral analysis in the range of 90--160 GHz of phase-locked, oscillating arrays of up to 2,450 Josephson junctions. Because of the excellent yield and uniformity of the nanobridge junctions, they successfully applied the junction technology to a wide variety of circuits. These circuits included transmission-line pulse formers and 32 and 64-bit shift registers. The 32-bit shift register was shown to operate at clock speeds near 100 GHz and is believed to be one of the faster and more complex digital circuit demonstrated to date using high temperature superconductor technology.
The use of renewable energy technologies is typically thought of as an integral part of creating and sustaining an environment that maximizes the overall quality of life of the Earths present inhabitants and does not leave an undue burden on future generations. Sandia National Laboratories has been a leader in developing many of these technologies over the last two decades. This paper describes innovative solar, wind and geothermal energy systems and components that Sandia is helping to bring to the marketplace. A common but special aspect of all of these activities is that they are conducted in partnership with non-federal government entities. A number of these partners are from New Mexico.
This paper reports on a surface mount assembly evaluation with a series of existing lead-free solders. The wettability of the lead-free solders under investigation was measured by the meniscometer/wetting balance technique. This data provided an initial screening assessment of viable candidates for prototype development. Assembly process capability was based on visual, mechanical and metallurgical analyses of prototype circuit boards. The study demonstrated the feasibility of using several of the lead-free solders tested in a surface mount application and identified specific areas (e.g., paste formulation, board finishes, reflow parameters) for improving the manufacturing performance.
The method of dynamic programming is applied to three example problems dealing with robot trajectory planning. The first two examples involve end-effector tracking of a straight line with rest-to-rest motions of planar two-link and three-link rigid robots. These examples illustrate the usefulness of the method for producing smooth trajectories either in the presence or absence of joint redundancies. The last example demonstrates the use of the method for rest-to-rest maneuvers of a single-link manipulator with a flexible payload. Simulation results for this example display interesting symmetries that are characteristic of such maneuvers. Details concerning the implementation and computational aspects of the method are discussed.
Correlation integrals have played a central role in optical pattern recognition. The success of correlation, however, has been limited. What is needed is a mathematical operation more complex than correlation. Suitably complex operations are the functionals defined on the Hilbert space of Lebesgue square integrable functions. Correlation is a linear functional of a parameter. In this paper, we develop a representation of functionals in terms of inner products or equivalently correlation functions. We also discuss the role of functionals in neutral networks. Having established a broad relation of correlation to pattern recognition, we discuss the computation of correlation functions using acousto-optics.
In recent years there has been increasing interest in using wafer-level isolation environments or pods (microenvironments) to provide a more controllable, cleaner wafer environment during wafer processing. It has been shown that pods can be effective in reducing the amount of particulate contamination on wafers during manufacturing. However, there have also been studies that indicate that pods and wafer boxes can be the source of condensible, molecular organic contamination. This paper summarizes the work that has been performed during the past year at Sandia National Laboratories` Contamination Free Manufacturing Research Center (CFMRC) on (1) devising standard, low-temperature, high sensitivity techniques to detect outgassing of volatile organic compounds (VOCs) from polymers used to construct wafer pods and (2) development of a technique that can be used to continuously measure the condensible contamination within pods so that the pod environment can be monitored during manufacturing. Although these techniques have been developed specifically for assessing contamination threats from wafer pods, they can be used to evaluate other potential contamination sources. The high sensitivity outgassing techniques can be used to evaluate outgassing of volatiles from other clean-room materials and the real-time outgassing sensor can be used to monitor contamination condensation in non-pod environments such as ballroom-type cleanrooms and minienvironments.
DC and pulsed-DC electromigration tests were performed at the Wafer-Level Pulsed-DC Electromigration Response and pulsed-DC electromigration tests were performed at the wafer level using standard and self-stressing test structures. DC characterization tests over a very large temperature range (180 to 560{degrees}C) were consistent with an interface diffusion mechanism in parallel with lattice diffusion. That data allowed for extraction of the respective activation energies and the diffusion coefficient of the rapid mechanism. The ability to extract simultaneously a defect-based diffusion coefficient and activation energy is significant given the extreme difficulty in making those measurements in aluminum. The pulsed-DC experiments were conducted over a range that includes the highest frequency to date, from DC to 500 MHz. Measurements were also made as a function of duty factor from 15% to 100% at selected frequencies. The data shows that the pulsed-DC lifetime is consistent with the average current density model at high (> 10 MHz) frequencies and showed no additional effects at the highest frequency tested (500 MHz). At low frequencies, we attribute the lessened enhancement to thermal effects rather than vacancy relaxation effects. Finally, the deviation in lifetime from the expected current density dependence, characterized over 1{1/2} orders of magnitude in current density, is explained in terms of a shift in the boundary condition for electromigration as the current density is decreased.
The topic of this technical presentation is Use Control Software. The nuclear weapon software design community is being subjected to many surety forces that are stretching the envelope of their designs. Given that software is a critical part of the use control system design, we must work to limit the errors of the software development process. The objective of this paper is to discuss a methodology that the author, as a member of the Security and Use Control Assessment Department, is working on. This is the first introduction of the proposed methodology. Software that is a part of any use control system, subsystem, device, or component is critical to the operation of that apparatus. The software is expected to meet the criteria of modern software quality. In a use control application, meeting the normal quality standards is short of the expectations in meeting the use control obligations. The NWC community expects the use control features of a nuclear weapon to provide assurance that the weapon is protected from unauthorized nuclear detonation. The methodology that the author is proposing will provide a focused scrutiny to software that is used in the hardware of use control systems, subsystems, devices, and components. The methodology proposes further scrutiny of the structure of the software, memory, variables, storage, and control features.
Scanning, ring-field lithographic cameras designed for 14-nm radiation can print 100-nm features on large chips. Mating high-efficiency illuminators are described.
This paper summarizes the recent hydrogeological investigations of several research organizations on waste confinement at the major radioactive waste (RW) burial sites immediately adjacent to the Chernobyl Nuclear Power Plant (Ch. NPP). Hydrogeological conditions and radiologic ground-water contamination levels are described. Ongoing ground-water monitoring practices are evaluated. The chemical and physical characteristics of the radionuclides within the burial sites are considered. Ground water and radionuclide transport modeling studies related to problems of the RW disposal sites are also reviewed. Current concerns on future impacts of the RW burial sites on the hydrological environment and water resources of the Ch.NPP area are discussed.
A new direction for the national laboratories is to assist US business with research and development, primarily through cooperative research and development agreements (CRADAs). Technology transfer to the private sector has been very successful as over 200 CRADAs are in place at Sandia. Because of these cooperative efforts, technology has evolved into some new areas not commonly associated with the former mission of the national laboratories. An example of this is the analysis of fabric structures. Explicit analyses and expertise in constructing parachutes led to the development of a next generation automobile airbag; which led to the construction, testing, and analysis of the Jet Propulsion Laboratory Mars Environmental Survey Lander; and finally led to the development of CAD based custom garment designs using 3D scanned images of the human body. The structural analysis of these fabric structures is described as well as a more traditional example Sandia with the test/analysis correlation of the impact of a weapon container.
Platform-independent Interaction Collaborative Environments (ICE) technologies include support for simultaneous display and control of unmodified X application software by two or more people, at separate locations, using different workstation hardware. Audio and video provide remote collaborators with the ability to discuss what they are all simultaneously seeing on their workstations. Remote pointing and marking capabilities are also provided independent of the application. The authors briefly describe their X application sharing work, and requirements for supporting tools, including multi-media. Finally they review some of the pilot project network applications of their work to robotics and manufacturing environments.
The SEAMIST{trademark} inverting membrane deployment system has been used successfully at the Mixed Waste Landfill Integrated Demonstration (MWLID) for multipoint vapor sampling/pressure measurement/permeability measurement/sensor integration demonstrations and borehole lining. Several instruments were deployed inside the SEAMIST{trademark} lined boreholes to detect metals, radionuclides, moisture, and geologic variations. The liner protected the instruments from contamination, maintained support of the uncased borehole wall, and sealed the total borehole from air circulation. The current activities have included the installation of three multipoint vapor sampling systems and sensor integration systems in 100-foot-deep vertical boreholes. A long term pressure monitoring program has recorded barometric pressure effects at depth with relatively high spatial resolution. The SEAMIST{trademark} system has been integrated with a variety of hydrologic and chemical sensors for in-situ measurements, demonstrating its versatility as an instrument deployment system which allows easy emplacement and removal. Standard SEAMIST{trademark} vapor sampling systems were also integrated with state-of-the-art VOC analysis technologies (automated GC, UV laser fluorometer). The results and status of these demonstration tests are presented.
Environmental and operator safety concerns are leading to the elimination of trichloroethylene (TCE) and chlorofluorocarbon (CFC) solvents in electronic component cleaning processes that remove rosin flux, organic and inorganic contamination, and particulates. Present processes depend heavily on these solvents for manual spray cleaning of small components and subassemblies. Use of alternative solvent systems can lead to longer processing times and reduced quality. Automated spray cleaning can improve the quality of the cleaning process, thus enabling the productive use of environmentally conscious materials, while minimizing personnel exposure to hazardous materials. In addition, the use of robotic and automated systems can reduce the manual handling of parts that necessitates additional cleaning. We describe the development of a prototype robotic system for cleaning electronic components in a spray cleaning workcell. An important feature of the prototype system is the capability to generate the robot paths and motions automatically from the CAD models of the part to be cleaned, and to embed cleaning process knowledge into the automatically programmed operations.
This document describes Sandia National Laboratories involvement with scientists and engineers at various organizations within the states of the Former Soviet Union (FSU). The purpose of these interactions is twofold: first, to acquire technical information to enhance United States technology and second, to assist FSU states in converting their defense-oriented industry to civilian, market- oriented business.
The technical feasibility of emplacing a barrier beneath a waste site using directionally drilled boreholes and permeation grouting was investigated. The benefits of this emplacement system are: (1) Directionally drilled boreholes provide access beneath a waste site without disturbing the waste; (2) interim containment of contaminants allows time for the development of remediation options; (3) in the interim, the volume of waste remains fixed; (4) barriers may enhance the effectiveness of in situ remediation actions; and (5) barrier systems may provide permanent waste containment .
The Solar Thermal Design Assistance Center (STDAC) at Sandia National Laboratories is a resource provided by the US Department of Energy`s Solar Thermal Program. Its major objectives are to accelerate the use of solar thermal systems through (a) direct technical assistance to users, (b) cooperative test, evaluation, and development efforts with private industry, and (c) educational outreach activities. This report outlines the major activities and accomplishments of the STDAC in Fiscal Year 1993. The report also contains a comprehensive list of persons who contacted the STDAC by telephone for information or technical consulting.
A dry barrier is a layer of geologic material that is dried by air flow. An active dry barrier system can be designed, installed, and operated as part of a landfill cover system. An active system uses blowers and fans to move air through a high-permeability layer within the cover system. Depending principally on the air-flow rate, it is possible for a dry barrier to remove enough water to substantially reduce the likelihood of water percolating through the cover system. If a material with a relatively great storage capacity, such as processed tuff, is used as the coarse layer, then the efficiency of the dry barrier will be increased.
The US Nuclear Regulatory Commission (NRC) maintains a technical training center at Chattanooga, Tennessee to provide appropriate training to both new and experienced NRC employees. This document describes a one-week course in reactor, safety concepts. The course consists of five modules: (1) historical perspective; (2) accident sequences; (3) accident progression in the reactor vessel; (4) containment characteristics and design bases; and (5) source terms and offsite consequences. The course text is accompanied by slides and videos during the actual presentation of the course.
An accident management strategy has been proposed in which the reactor coolant system is intentionally depressurized during an accident. The aim is to reduce the containment pressurization that would result from high pressure ejection of molten debris at vessel breach. Probabilistic risk assessment (PRA) methods were used to evaluate this strategy for the Surry nuclear power plant. Sensitivity studies were conducted using event trees that were developed for the NUREG-1150 study. It was found that depressurization (intentional or unintentional) had minimal impact on the containment failure probability at vessel breach for Surry because the containment loads assessed for NUREG-1150 were not a great threat to the containment survivability. An updated evaluation of the impact of intentional depressurization on the probability of having a high pressure melt ejection was then made that reflected analyses that have been performed since NUREG-1150 was completed. The updated evaluation confirmed the sensitivity study conclusions that intentional depressurization has minimal impact on the probability of a high pressure melt ejection. The updated evaluation did show a slight benefit from depressurization because depressurization delayed core melting, which led to a higher probability of recovering emergency core coolant injection, thereby arresting the core damage.
Vertical electric fields, azimuthal magnetic fields, and earth step potentials at ground level have been measured at 10 and 20 meters from the base of triggered lightning flashes. For incident stroke peak currents in the range of 4.4 to 29 kA, vertical electric field change amplitudes as high as 210 kV/m were observed at 10 m, with rise times of the order of a few microseconds. Magnetic fields were found to follow Ampere`s law closely at both 10 and 20 m. Earth step potentials measured over a 0.5-m radial distance at the 10-m and 20m stations were linear with and had the same waveforms as the stroke currents. The step voltages exhibited a l/r distance dependence between the two measurement distances. A model that incorporates the presence of a thin surface layer, due to rain water saturation, of much higher conductivity than the bulk of the underlying earth is proposed to explain the observed behavior. Tests were also carried out to evaluate the effectiveness of several concepts for protecting a small exposed object, such as a piece of ordnance at the site of a transportation accident, from either a direct strike or from the indirect effects of electromagnetic fields produced by a nearby lightning flash to ground. Photographs of the occurrence of significant radial filamentary arcing along the surface of the ground from the strike points were acquired. This type of arcing, with a maximum radial extent of at least 20 m, was observed on six of seven of triggered flashes and on all strokes of 15-kA peak amplitude or higher.
Goal was to obtain dynamic mechanical property data on a quartz phenolic (abbreviated QP) composite. Shock loading and shock release measurements have been conducted using impact techniques utilizing both a light-gas gun and a powder gun at impact pressures up to 20 GPa. The primary diagnostic tool used was a velocity interferometer. The data analysis includes Hugoniot measurements to give both pressure-particle velocity and shock velocity-particle velocity relationships; spall measurements to determine the fracture stress at which the material spells; and attenuation measurements to determine the shock attenuation with material thickness. The QP Hugoniot relationship was found to be significantly different than that of a phenolic without a filler material indicating that the impedance of the QP used in this investigation was higher. The spall strength was measured to be {approximately}0.075 GPa, similar to nonfilled phenolic, which indicated that the presence of quartz fibers was not contributing to the fracture strength. The material was found to attenuate an imposed shock of approximately 6.3 GPa pressure and 0.18 {mu}s to 50% of the initial impact value after a propagation distance of 7mm.
Sandia National Laboratories is currently involved in the optimization of a Plane Shock Generator Explosive Lens (PSGEL). The PSGEL component consists of a detonator, explosive, brass cone and tamper housing. The purpose of the PSGEL component is to transmit a plane shock wave through the 4340 steel bulkhead (wave separator) which has a ferro-electric (PZT)ceramic disk attached to the opposite surface of the steel bulkhead. The planar shock wave depolarizes the PZT 65/35 ferro-electric ceramic to produce an electrical output. One aspect of the optimization program involves the possible replacement of 4340 steel with PH13-8Mo steel for the bulkhead. These materials, as well as the PZT 65/35 ferro-electric ceramic and the brass for the cone, required the stock characterization with respect to Hugoniot parameters. The work presented here gives the shock Hugoniot values for these four materials and documents their measurements.
CIRCE2 is a computer code for modeling the optical performance of three-dimensional dish-type solar energy concentrators. Statistical methods are used to evaluate the directional distribution of reflected rays from any given point on the concentrator. Given concentrator and receiver geometries, sunshape (angular distribution of incident rays from the sun), and concentrator imperfections such as surface roughness and random deviation in slope, the code predicts the flux distribution and total power incident upon the target. Great freedom exists in the variety of concentrator and receiver configurations that can be modeled. Additionally, provisions for shading and receiver aperturing are included.- DEKGEN2 is a preprocessor designed to facilitate input of geometry, error distributions, and sun models. This manual describes the optical model, user inputs, code outputs, and operation of the software package. A user tutorial is included in which several collectors are built and analyzed in step-by-step examples.