A diode-side-pumped discrete-optic Er{sup 3+} :YAG laser employs pump-light coupling through a sapphire plate diffusion-bonded to the laser slab, removing heat directly at the pump face of the slab instead of requiring conduction through to its far side. This lowers the temperature in the gain region and gives reduced thermal lensing, which produces exceptional beam quality (M{sup 2} {approx} 1.3) at output powers {approx} 0.3 Watt. Powers above 1 Watt have been demonstrated with peak slope efficiencies {approx}20%. The novel architecture is also applicable to other side-pumped lasers.

Modular fixturing kits are sets of components used for flexible, rapid construction of fixtures. A modular vise is a parallel-jaw vise, each jaw of which is a modular fixture plate with a regular grid of precisely positioned holes. To fixture a part, one places pins in some of the holes so that when the vise is closed, the part is reliably located and completely constrained. The modular vise concept can be adapted easily to the design of modular parallel-jaw grippers for robots. By attaching a grid-plate to each jaw of a parallel-jaw gripper, one gains the ability to easily construct high-quality grasps for a wide variety of parts from a standard set of hardware. Wallack and Canny developed an algorithm for planning planar grasp configurations for the modular vise. In this paper, the authors expand this work to produce a 3-d fixture/gripper design tool. They describe several analyses they have added to the planar algorithm, including a 3-d grasp quality metric based on force information, 3-d geometric loading analysis, and inter-gripper interference analysis. Finally, the authors describe two applications of their code. One of these is an internal application at Sandia, while the other shows a potential use of the …

We have developed a fully three-dimensional model for the performance of flashlamp pumped laser amplifiers. The model uses a reverse ray-trace technique to calculate the pumping of the laser glass by the flashlamp radiation. We have discovered several different methods by which we can speed up the calculation of the gain profile in a amplifier. The model predicts the energy-storage performance of the Beamlet amplifiers to better than 5%. This model will be used in the optimization of the National Ignition Facility (NIF) amplifier design.

The ability to image complex geologies such as salt domes in the Gulf of Mexico and thrusts in mountainous regions is a key to reducing the risk and cost associated with oil and gas exploration. Imaging these structures, however, is computationally expensive. Datasets can be terabytes in size, and the processing time required for the multiple iterations needed to produce a velocity model can take months, even with the massively parallel computers available today. Some algorithms, such as 3D, finite-difference, prestack, depth migration remain beyond the capacity of production seismic processing. Massively parallel processors (MPPs) and algorithms research are the tools that will enable this project to provide new seismic processing capabilities to the oil and gas industry. The goals of this work are to (1) develop finite-difference algorithms for 3D, prestack, depth migration; (2) develop efficient computational approaches for seismic imaging and for processing terabyte datasets on massively parallel computers; and (3) develop a modular, portable, seismic imaging code.

The thermal mass flow controller, or MFC, has become an instrument of choice for the monitoring and controlling of process gas flow throughout the materials processing industry. These MFCs are used on CVD processes, etching tools, and furnaces and, within the semiconductor industry, are used on 70% of the processing tools. Reliability and accuracy are major concerns for the users of the MFCs. Calibration and characterization technologies for the development and implementation of mass flow devices are described. A test facility is available to industry and universities to test and develop gas floe sensors and controllers and evaluate their performance related to environmental effects, reliability, reproducibility, and accuracy. Additional work has been conducted in the area of accuracy. A gravimetric calibrator was invented that allows flow sensors to be calibrated in corrosive, reactive gases to an accuracy of 0.3% of reading, at least an order of magnitude better than previously possible. Although MFCs are typically specified with accuracies of 1% of full scale, MFCs may often be implemented with unwarranted confidence due to the conventional use of surrogate gas factors. Surrogate gas factors are corrections applied to process flow indications when an MFC has been calibrated on a laboratory-safe surrogate …

A coded aperture neutron imaging system developed at Brookhaven National Laboratory (BNL) has demonstrated that it is possible to record not only a flux of thermal neutrons at some position, but also the directions from whence they came. This realization of an idea which defied the conventional wisdom has provided a device which has never before been available to the nuclear physics community. A number of potential applications have been explored, including (1) counting warheads on a bus or in a storage area, (2) investigating inhomogeneities in drums of Pu-containing waste to facilitate non-destructive assays, (3) monitoring of vaults containing accountable materials, (4) detection of buried land mines, and (5) locating solid deposits of nuclear material held up in gaseous diffusion plants.

Prior to the DF-4 boiling water reactor (BWR) severe fuel damage (SFD) experiment conducted at the Sandia National Laboratories in 1986, no experimental data base existed for guidance in modeling core component behavior under postulated severe accident conditions in commercial BWRs. This paper will present the lessons learned from the DF-4 experiment (and subsequent German CORA BWR SFD tests) and the impact on core models in the current generation of SFD codes. The DF-4 and CORA BWR test assemblies were modeled on the core component designs circa 1985; that is, the 8 x 8 fuel assembly with two water rods and a cruciform control blade constructed of B{sub 4}C-filled tubelets. Within the past ten years, the state-of-the-art with respect to BWR core component development has out-distanced the current SFD experimental data base and SFD code capabilities. For example, modern BWR control blade design includes hafnium at the tips and top of each control blade wing for longer blade operating lifetimes; also water rods have been replaced by larger water channels for better neutronics economy; and fuel assemblies now contain partial-length fuel rods, again for better neutronics economy. This paper will also discuss the implications of these advanced fuel assembly and …

Nanostructures are defined to be ultrasmall structures and devices with dimensions less than or equal to 100 nm. Conventional methods for making thin film structures involve exposure of a thin layer of a polymer resist on a suitable substrate to define a pattern, which is then developed and used to fabricate the structures either by deposition, or by etching. Resistless methods of patterning, followed by epitaxial growth could significantly simplify nanofabrication by eliminating a number of processing steps associated with the application, exposure, development, and removal of the resist. The molecular size effect with polymer based resists such as PMMA is believed to be a significant factor in limiting the resolution (grain size) in electron beam lithography (EBL) to 10 nm. Surface adsorption layers such as the hydride layer on the Si surface are characterized by relatively strong chemical bonding which produces a highly uniform coverage that terminates at a single monolayer. Because of these properties surface adsorption layers are attractive candidates as ultrathin, ultrahigh resolution resists for electron beam patterning. In this paper, the authors report on results concerning electron beam induced patterning of the surface hydride layer on silicon, using a scanning electron beam lithography (SEBL) system. The …

This paper represents an overview of analyses conducted on the TRU database maintained by the Los Alamos National Laboratory (LANL). This evaluation was conducted to support the ``TRU Waste Workoff Strategies`` document and provides an estimation of the waste volume that potentially could be certified and ready for shipment to (WIPP) in April of 1998. Criteria defined in the WIPP WAC, including container type, weight limits, plutonium fissile gram equivalents and decay heat, were used to evaluated the waste for compliance. LANL evaluated the containers by facility and by waste stream to determining the most efficient plan for characterization and certification of the waste. Evaluation of the waste presently in storage suggested that 40- 60% potentially meets the WIPP WAC Rev. 5 criteria.

The Los Alamos National Laboratory (LANL) has full capability to characterize transuranic (TRU) waste for shipment to and disposal at the Waste Isolation Pilot Plant (WIPP) for its projected opening. LANL TRU waste management operations also include facilities to repackage both drums of waste found not to be certifiable for WIPP and oversized boxes of waste that must be size reduced for shipment to WIPP. All characterization activities and repackaging are carried out under a quality assurance program designed to meet Carlsbad Area Office (CAO) requirements. The flow of waste containers through characterization operations, the facilities used for characterization, and the electronic data management system used for data package preparation and certification of TRU waste at LANL are described.

The Los Alamos National Laboratory (LANL) has begun characterizing transuranic (TRU) waste in order to comply with New Mexico regulations, and to prepare the waste for shipment and disposal at the Waste Isolation Pilot Plant (WIPP), near Carlsbad, New Mexico. Sampling consists of removing some head space gas from each drum, removing a core from a few drums of each homogeneous waste stream, and visually characterizing a few drums from each heterogeneous waste stream. The gases are analyzed by GC/MS, and the cores are analyzed for VOC`s and SVOC`s by GC/MS and for metals by AA or AE spectroscopy. The sampling and examination projects are conducted in accordance with the ``DOE TRU Waste Quality Assurance Program Plan`` (QAPP) and the ``LANL TRU Waste Quality Assurance Project Plan,`` (QAPjP), guaranteeing that the data meet the needs of both the Carlsbad Area Office (CAO) of DOE and the ``WIPP Waste Acceptance Criteria, Rev. 5,`` (WAC).

This paper presents an overview of the activities being planned and implemented to certify newly generated contact handled transuranic (TRU) waste produced by Los Alamos National Laboratory`s (LANL`s) Plutonium Facility. Certifying waste at the point of generation is the most important cost and labor saving step in the WIPP certification process. The pedigree of a waste item is best known by the originator of the waste and frees a site from expensive characterization activities such as those associated with legacy waste. Through a cooperative agreement with LANLs Waste Management Facility and under the umbrella of LANLs WIPP-related certification and quality assurance documents, the Plutonium Facility will be certifying its own newly generated waste. Some of the challenges faced by the Plutonium Facility in preparing to certify TRU waste include the modification and addition of procedures to meet WIPP requirements, standardizing packaging for TRU waste, collecting processing documentation from operations which produce TRU waste, and developing ways to modify waste streams which are not certifiable in their present form.

This paper describes the new computer-based transuranic (TRU) Waste Management System (WMS) being implemented at the Plutonium Facility at Los Alamos National Laboratory (LANL). The Waste Management System is a distributed computer processing system stored in a Sybase database and accessed by a graphical user interface (GUI) written in Omnis7. It resides on the local area network at the Plutonium Facility and is accessible by authorized TRU waste originators, count room personnel, radiation protection technicians (RPTs), quality assurance personnel, and waste management personnel for data input and verification. Future goals include bringing outside groups like the LANL Waste Management Facility on-line to participate in this streamlined system. The WMS is changing the TRU paper trail into a computer trail, saving time and eliminating errors and inconsistencies in the process.

Albuquerque, New Mexico, is located along the Rio Grande in central New Mexico, at an elevation of 5280 feet. Albuquerque`s climate reflects its high desert setting; average annual precipitation in the basin is only 8 to 10 inches. The Albuquerque metropolitan area is part of the rapidly growing {open_quotes}sunbelt{close_quotes} region of the southwestern United States and is undergoing rapid development. The municipal, industrial, and residential water needs of the entire population are currently met by groundwater, while agricultural needs within the basin are met by surface water diverted from the Rio Grande. While the city is blessed with an extremely productive aquifer, current metropolitan area annual groundwater extractions of 170,000 acre-feet far exceed the sustainable yield of the aquifer. Continued drawdown will lead to greater pumping costs, ground surface subsidence problems, and eventual aquifer depletion. At the same time, industrial and non-point-source contamination and naturally occurring arsenic levels are raising concerns about groundwater quality. New Mexico water law has required the City to acquire surface water rights and allocations on the Rio Grande sufficient to offset estimated losses from the river induced by the City`s groundwater extraction. It has become increasingly clear that the induced recharge had been greatly overestimated, …

Alpha-driven toroidal Alfven eigenmodes (TAEs) are observed as predicted by theory in the post neutral beam phase in high central q (safety factor) deuterium-tritium (D-T) plasmas in the Tokamak Fusion Test Reactor (TFTR). The mode location, poloidal structure and the importance of q profile for TAE instability are discussed. So far no alpha particle loss due to these modes was detected due to the small mode amplitude. However, alpha loss induced by kinetic ballooning modes (KBMs) was observed in high confinement D-T discharges. Particle orbit simulation demonstrates that the wave-particle resonant interaction can explain the observed correlation between the increase in alpha loss and appearance of multiple high-n (n {ge} 6, n is the toroidal mode number) modes.

The Alternative LEU Design for the FRM-II proposed by the RERTR Program at Argonne National Laboratory (ANL) has a compact core consisting of a single fuel element that uses LEU silicide fuel with a uranium density of 4.5 g/cm[sup 3] and has a power level of 32 MW. Both the HEU design by the Technical University of Munich (TUM) and the alternative LEU design by ANL have the same fuel lifetime (50 days) and the same neutron flux performance (8 x 10[sup 14] n/cm[sup 2]/s in the reflector). LEU silicide fuel with 4.5 g/cm[sup 3] has been thoroughly tested and is fully-qualified, licensable, and available now for use in a high flux reactor such as the FRM-II. Computer models for the HEU and LEU designs have been exchanged between TUM and ANL and discrepancies have been resolved. The following issues are addressed: qualification of HEU and LEU silicide fuels, stability of the fuel plates, gamma heating in the heavy water reflector, a hypothetical accident involving the configuration of the reflector, a loss of primary coolant flow transient due to an interrupted power supply, the radiological consequences of larger fission product and plutonium inventories in the LEU core, and cost and …

An early prototype of the core software for on-line computing systems for the PHENIX detector at RHIC has been developed using the Shlaer-Mellor OOA/RD method, including the automatic generation of C++ source code using a commercial translation engine and {open_quotes}architecture{close_quotes}.

Crystals of Yb{sup 3+}:Sr{sub 1-x}Ba{sub x}(PO{sub 4}){sub 3}F (0 < x < 5) have been investigated as a means to obtain broader absorption bands than are currently available with Yb{sup 3+}:S-FAP [Yb{sup 3+}: Sr{sub 5}(PO{sub 4}){sub 3}F], thereby improving diode-pumping efficiency for high peak power applications. Large diode-arrays have a FWHM pump band of >5 nm while the FWHM of the 900 nm absorption band for Yb:S-FAP is 5.5 nm; therefore, a significant amount of pump power can be wasted due to the nonideal overlap. Spectroscopic analysis of Yb:Sr{sub 5-x}Ba{sub x}-FAP crystals indicates that adding barium to the lattice increases the pump band to 13-16 run which more than compensates for the diode-array pump source without a detrimental reduction in absorption cross section. However, the emission cross section decreases by approximately half with relatively no effect on the emission lifetime. The small signal gain has also been measured and compared to the parent material Yb:S-FAP and emission cross sections have been determined by the method of reciprocity, the Filchtbauer-Ladenburg method, and small signal gain. Overall, Yb{sup 3+}:Sr{sub 5-x}Ba{sub x}(PO{sub 4}){sub 3}F crystals appear to achieve the goal of nearly matching the favorable thermal and laser performance properties of Yb:S-FAP while …

Component phases of Al salt cake or products from processing salt cake, resist dissolution, a key first step in most analysis procedures. In this work (analysis support to a study of conversion of salt cake fines to value-added oxide products), analysis methods were adapted or devised for determining leachable salt, total halides (Cl and F), Al metal, and elemental composition. Leaching of salt cake fines was by ultrasonic agitation with deionized water. The leachate was analyzed for anions by ion chromatography and for cations by ICP-atomic emission spectroscopy. Only chloride could be measured in the anions, and charge balances between cations and chloride were near unity, indicating that all major dissolved species were chloride salts. For total halides, the chloride and fluorides components were first decomposed by KOH fusion, and the dissolved chloride and fluoride were measured by ion chromatography. Al metal in the fines was determined by a hydrogen evolution procedure adapted for submilligram quantities of metallic Al: the Al was reacted with HCl in a closed system containing a measured amount of high-purity He. After reaction, the H/He ratio was measured by mass spectroscopy. Recoveries of Al metal standards (about 30mg) averaged 93%. Comparison of the acid evolution …

The response of fuel in a boiling water reactor to the rod drop accident (RDA) was studied using the RAMONA-4B computer code. Calculations of this design-basis event has been done conservatively because there was margin to the fuel failure criterion of 170 cal/g. Because high burnup fuel may fail at much lower fuel enthalpies, the best-estimate of the enthalpy and the uncertainty is of interest. In part of this study, calculations assessed the sensitivity to reactor conditions such as control rod pattern, inlet subcooling, and fuel burnup. It was shown that fuel enthalpy at any location in the region surrounding the dropped rod depends on the rod worth, the distance from the dropped rod, and the burnup of the fuel. The study also calculated the sensitivity to parameters whose modeling introduces significant uncertainty which may increase with burnup. These parameters are the control rod worth, Doppler reactivity coefficient, delayed neutron precursor fraction, and fuel specific heat. The results of the sensitivity studies were used in a model to determine the random uncertainty in the fuel enthalpy. The standard deviation for the calculated fuel enthalpy was estimated to be 37%. Therefore, the limiting bundle fuel enthalpy might be 75% higher than …

The response of fuel in a boiling water reactor to the rod drop accident (RDA) was studied using the RAMONA-4B computer code. In this study, a fit of RAMONA-4B bundle powers was used to estimate the local power peaking. It was determined that the peaking factor could be 25% higher than the factor usually assumed for RDA analysis. Combining this error with the 2 sigma random error means that for this analysis the actual fuel rod enthalpy could be 100% larger than calculated by RAMONA-4B. This is much larger than the uncertainty in most parameters that are calculated with best-estimate methods for other design-basis events.

The collapse of the Soviet Union has left many of its scientific institutes and technical universities without their traditional backbone of financial support. In an effort to stem the export of science to nations advocating nuclear proliferation, and to acquire potentially useful technology, several US government-sponsored programs have arise to mine the best of former USSR scientific advances. In the field of metallurgy, the earliest institutes to be investigated by Sandia National Laboratories are located in Ukraine. In particular, scientists at the State Metallurgical Academy have developed unique porous metals, resembling what could be described as gas-solid ``eutectic``. While porous metals are available in the US and other western countries, none have the remarkable structure and properties of these materials. Sandia began a collaborative program with the Ukrainian scientists to bring this technology to the US, verify the claims regarding these materials, and begin production of the so-called Gasars. This paper will describe the casting process technology and metallurgy associated with the production of Gasars, and will review the progress of the collaborative project.

The objectives of this study are (1) to parallelize a 3-dimensional hydrogeochemistry code and (2) to apply the parallel code to a proposed waste disposal site at the Oak Ridge National Laboratory (ORNL). The 2-dimensional hydrogeochemistry code HYDROGEOCHEM, developed at the Pennsylvania State University for coupled subsurface solute transport and chemical equilibrium processes, was first modified to accommodate 3-dimensional problem domains. A bi-conjugate gradient stabilized linear matrix solver was then incorporated to solve the matrix equation. We chose to parallelize the 3-dimensional code on the Intel Paragons at ORNL by using an HPF (high performance FORTRAN) compiler developed at PGI. The data- and task-parallel algorithms available in the HPF compiler proved to be highly efficient for the geochemistry calculation. This calculation can be easily implemented in HPF formats and is perfectly parallel because the chemical speciation on one finite-element node is virtually independent of those on the others. The parallel code was applied to a subwatershed of the Melton Branch at ORNL. Chemical heterogeneity, in addition to physical heterogeneities of the geological formations, has been identified as one of the major factors that affect the fate and transport of contaminants at ORNL. This study demonstrated an application of the 3-dimensional …

A fast, continuous, wavelet transform, based on Shannon`s sampling theorem in frequency space, has been developed for use with continuous mother wavelets and sampled data sets. The method differs from the usual discrete-wavelet approach and the continuous-wavelet transform in that, here, the wavelet is sampled in the frequency domain. Since Shannon`s sampling theorem lets us view the Fourier transform of the data set as a continuous function in frequency space, the continuous nature of the functions is kept up to the point of sampling the scale-translation lattice, so the scale-translation grid used to represent the wavelet transform is independent of the time- domain sampling of the signal under analysis. Computational cost and nonorthogonality aside, the inherent flexibility and shift invariance of the frequency-space wavelets has advantages. The method has been applied to forensic audio reconstruction speaker recognition/identification, and the detection of micromotions of heavy vehicles associated with ballistocardiac impulses originating from occupants` heart beats. Audio reconstruction is aided by selection of desired regions in the 2-D representation of the magnitude of the transformed signal. The inverse transform is applied to ridges and selected regions to reconstruct areas of interest, unencumbered by noise interference lying outside these regions. To separate micromotions …