We characterize the effects of ionizing radiation on oxynitrides furnace-grown in N{sub 2}O. Results are presented on hole trapping, interface trap creation, time-dependent hole annealing, and hole de-trapping using thermally-stimulated current analysis.
The design of a multitasking behavioral control system for the Robotic All Terrain Lunar Exploration Rover (RATLER) is described. The control system design attempts to ameliorate some of the problems noted by some researchers when implementing subsumption or behavioral control systems, particularly with regard to multiple processor systems and real-time operations. The architecture is designed to allow both synchronous and asynchronous operations between various behavior modules by taking advantage of intertask communications channels, and by implementing each behavior module and each interconnection node as a stand-alone task. The potential advantages of this approach over those previously described in the field are discussed. An implementation of the architecture is planned for a prototype Robotic All Terrain Lunar Exploration Rover (RATLER) currently under development, and is briefly described.
One of the common oil-field wellbore problems is paraffin deposition. Even though hot oiling or hot watering is usually the first method tried for removing paraffin, few operators appreciate the limitations of ``hot oiling`` and the potential for the fluid to aggravate well problems and cause formation damage. Field tests have shown that the chemical and thermal processes that occur during ``hot oiling`` are very complex and that there are significant variations in practices among operators. Key issues include: (1) During a typical hot oiling job, a significant amount of the fluid injected into the well goes into the formation, and hence, particulates and chemicals in the fluid have the potential to damage the formation. (2) Hot oiling can vaporize oil in the tubing faster than the pump lifts oil. This interrupts paraffin removal from the well, and thus the wax is refined into harder deposits, goes deeper into the well, and can stick rods. These insights have been used to determine good ``hot oiling`` practices designed to maximize wax removal and minimize formation damage.
The correlation of hot carrier stress and ionization induced gain degradation in npn BJTs was studied to determine if hot-carrier stress could be used as a hardness assurance tool for total dose. The correlation was measured at the wafer level and for several hardening variations for a single process technology. Additional experiments are planned and will be presented in the full paper. Based on a detailed physical analysis of the mechanisms for hot-carrier stress and ionization no correlation was expected. The results demonstrated the lack of correlation and indicate that hot-carrier stress degradation is not a predictor of total dose response.
Robotic automation is examined as a possible alternative to manual spent nuclear fuel, transport cask and Multi-Purpose canister (MPC) handling at a Monitored Retrievable Storage (MRS) facility. Automation of key operational aspects for the MRS/MPC system are analyzed to determine equipment requirements, through-put times and equipment costs is described. The economic and radiation dose impacts resulting from this automation are compared to manual handling methods.
Sandia National Laboratories has designed and built an electrical test system which fulfills a requirement to quickly, accurately and precisely measure the resistance of conductors formed on Printed Wiring Board (PWB) substrates. This requirement stems from the need to measure small variations in conductors and thus to determine the source of the variations. With this test technology, experiments can be conducted with new materials, equipment, and processes in a timely and scientific manner. Conductor formation processes can be optimized for both conductor yield and uniformity, and process equipment can be fine-tuned prior to processing product to ensure that conductor attributes fulfill requirements. Significant resources have been spent by Sandia National Laboratories and Texas Instruments modifying commercially available two-probe testers. AT&T has built a two-probe tester and obtained a commercially available ``bed-of-nails`` test system. The two-probe systems have limitations in speed and precision; the ``bed-of-nails`` system has proved to be superior to the two-probe designs but is expensive, and lacks test pattern flexibility and ease of use. Due to the need to establish a testing technology which meets the requirements of Sandia National Laboratories and the National Center for Manufacturing Sciences PWB Consortium Imaging Team (current Imaging Team members; AT&T, Texas Instruments, AlliedSignal, IBM, and Sandia National Laboratories), a prototype test system was designed and built by Sandia. This paper will discuss the design and performance of the test system and the results of a comparison to other test systems.
A simple method to estimate the threshold-voltage shift in MOSFETs due to low-dose-rate ionizing irradiation based on MIL-STD-883D Method 1019.4 is demonstrated. The realm of applicability of this approach is explored.
Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is ``built-in`` through statistical process control (SPC) of technology parameters relevant to the radiation response, test structure to integrated circuit (IC) correlations, and techniques for extrapolating laboratory test results to varying radiation scenarios. At the same time, there has been renewed interest in the use of commercial technology -- with its enhanced performance, reduced cost, and higher reliability -- in military and space systems. In this paper, we initially demonstrate the application of QML techniques to assure and control the radiation response of hardened technologies. Through several examples, we demonstrate intra-die, wafer-to-wafer, and lot-to-lot variations in a hardened technology. We observe 10 to 30% variations in key technology parameters that result from variability in geometry, process, and design layout. Radiation-induced degradation is seen to mirror preirradiation characteristics. We then evaluate commercial technologies and report considerably higher variability in radiation hardness, i.e., variations by a factor of two to five. This variability is shown to arise from a lack of control of technology parameters relevant to the radiation response, which a commercial manufacturer has no interest in controlling in a normal process flow.
Photonic packaging concepts using anamorphic microlenses and second-order grating couplers were demonstrated by coupling a ridge waveguide to an out-of-plane single-mode fiber.
This paper presents results of ex-vessel boiling experiments performed in the CYBL (CYlindrical BoiLing) facility. CYBL is a reactor-scale facility for confirmatory research of the flooded cavity concept for accident management. CYBL has a tank-within-a-tank design; the inner tank simulates the reactor vessel and the outer tank simulates the reactor cavity. Experiments with uniform and edge-peaked heat flux distributions up to 20 W/cm{sup 2} across the vessel bottom were performed. Boiling outside the reactor vessel was found to be subcooled nucleate boiling. The subcooling is mainly due to the gravity head which results from flooding the sides of the reactor vessel. The boiling process exhibits a cyclic pattern with four distinct phases: direct liquid/solid contact, bubble nucleation and growth, coalescence, and vapor mass dispersion (ejection). The results suggest that under prototypic heat load and heat flux distributions, the flooded cavity in a passive pressurized water reactor like the AP-600 should be capable of cooling the reactor pressure vessel in the central region of the lower head that is addressed by these tests.
A high-performance high-speed optical phase modulator for photonic integrated circuit (PIC) use is described. Integration of these optical phase modulators into a real system (compass) is also discussed. The optical phase modulators are based on depletion-edge translation and have experimentally provided optical phase shifts in excess of 60{degrees}/V{center_dot}mm with approximately 4 dB/cm loss while simultaneously demonstrating bandwidths in excess of 10 GHz.
VISAR (Velocity Interferometer System for Any Reflector) is a specialized Doppler interferometer system that is gaining world-wide acceptance as the standard for shock phenomena analysis. The VISAR`s large power and cooling requirements, and the sensitive and complex nature of the interferometer cavity have restricted the traditional system to the laboratory. This paper describes the new portable VISAR, its peripheral sensors, and the role it played in optically measuring ground shock of an underground nuclear detonation. The solid State VISAR uses a prototype diode pumped ND:YAG laser and solid state detectors that provide a suitcase-size system with low power requirements. A special window and sensors were developed for fiber optic coupling (1 kilometer long) to the VISAR. The system has proven itself as a reliable, easy to use instrument that is capable of field test use and rapid data reduction using only a notebook personal computer (PC).
Regulatory compliance and effective management of the nation`s TRU waste requires knowledge about the constituents present in the waste. With limited resources, the DOE needs a cost-effective characterization program. In addition, the DOE needs a method for predicting the present and future analytical requirements for waste characterization. Thus, a strategy for predicting the present and future waste characterization needs that uses current knowledge of the TRU inventory and prioritization of the data needs is presented.
Low-energy alpha particles emitted from packaging and high-energy heavy ions in space possess the capability of causing changes in memory state when incident on semiconductor memory cans and latch circuits. This phenomenon of single-event upset (SEU) is caused by collection of charge created as the particle travels through a sensitive volume of the device. As devices are continually down-sized, the corresponding decrease in amount of charge held on storage nodes increases device susceptibility to SEU. Solutions to harden devices to SEU require an in-depth understanding of the basic mechanisms responsible for upset. Also, a detailed understanding of the charge-collection volume is critical for predicting on-orbit error rates. Previous work has revealed the formation of a field funnel in response to the particle strike. Analytical models that treat the funnel in a time-averaged sense have been developed, and have been reasonably successful at predicting total collected charge for particles with low linear energy transfer (LET). Sophisticated two- and three-dimensional simulations have been used to investigate the funneling process more rigorously; however, the interplay between the funnel and collection by drift and diffusion has remained somewhat obscure. In this paper, we present an examination of fundamental charge-collection mechanisms and the role of the funnel, using advanced three-dimensional drift-diffusion modeling. We then apply the insight gained to address radiation hardness issues in light of current technology trends.
Sandia National Laboratories has undertaken the Agile Product Realization for Innovative electroMEchanical Devices (A-PRIMED) pilot project to develop and implement technologies for agile design and manufacturing of electrochemical components. Emphasis on information-driven processes, concurrent engineering and multi-functional team communications makes computer-supported cooperative work critical to achieving significantly faster product development cycles. This report describes analyses conducted in developing communications requirements and a communications plan that addresses the unique communications demands of an agile enterprise.
In this paper we describe an algorithm by which obstructions and surface features in an underground storage tank can be modeled and used to generate virtual barrier function for a real-time telerobotic system, which provides an aid to the operator for both real-time obstacle avoidance and for surface tracking. The algorithm requires that the slave`s tool and every object in the waste storage tank be decomposed into convex polyhedral primitives, with the waste surface modeled by triangular prisms. Intrusion distance and extraction vectors are then derived at every time step by applying Gilbert`s polyhedra distance algorithm, which has been adapted for the task. This information is then used to determine the compression and location of nonlinear virtual spring-dampers whose total force is summed and applied to the manipulator/teleoperator system. Experimental results using a PUMA 560 and a simulated waste surface validate the approach, showing that it is possible to compute the algorithm and generate smooth, realistic pseudo forces for the teleoperator system using standard VME bus hardware.
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 Earth`s present inhabitants and does not leave an undue burden on future generations. Sandia National Laboratories has been a leader in developing and deploying many of these technologies over the last two decades. A common but special aspect of all of these activities is that they are all conducted in cooperation with various types of partners. Some of these partners have an interest in seeing these systems grow in the marketplace, while others are primarily concerned with economic benefits that can come from immediate use of these renewable energy systems. This paper describes solar thermal and photovoltaic technology activities at Sandia that are intended to accelerate the commercialization of these solar systems.
Scenario developments is part of the iterative performance assessment (PA) process for the Waste Isolation Pilot Plant (WIPP). Scenario development for the WIPP has been the subject of intense external review, and is certain to be the subject of continued scrutiny as the project proceeds toward regulatory compliance. The principal means of increasing confidence is this aspect of the PA will be through the use of a systematic and thorough procedure toward developing the scenarios and conceptual models on which the assessment is to be based. Early and ongoing interaction with project reviewers can assist with confidence building. Quality of argument and clarity of presentation in PA will be of key concern. Appropriate tools are required for documenting and tracking assumptions, through a single assessment phase, and between iterative assessment phases. Risks associated with future human actions are of particular concern to the WIPP project, and international consensus on the principles for incorporation of future human actions in assessments would be valuable.
Thermally-stimulated-current and capacitance-voltage measurements reveal enhanced hole trapping in bipolar spacer-oxide capacitors irradiated at 0 V at low dose rates. Possible mechanisms and implications for bipolar low-rate response are discussed.
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.