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We built a bi-directional scatter diagnostics to measure and quantify losses due to scattering and absorption of harmonic conversion crystals (DKDP) for the National Ignition Facility (NIF). The main issues to be addressed are (1) amount of total energy reaching the target if the target hole was {+-}200 {micro}rad in size, (2) distribution of energy inside the target hole, (3) collateral damage of other optics by scattered light. The scatter diagnostics enables angle-resolved measurements at 351 nm, and is capable of both near specular transmission and large angle scatter measurements. In the near specular setup, the transmission can be measured within {+-}65 {micro}rad up to {+-}60 mrad acceptance angle. A silicon photo detector and a scientific-grade CCD camera provide total energy and energy distribution. A linear swing arm detection system enables large angle scatter measurements of 360{sup o}, in principal, with step sizes as small as 0.01{sup o} and different collection angle ranging between 1 and 20 mad. In this paper, scatter effects from laser damage and final finishing process of DKDP are discussed.

This report describes results from analyses performed to characterize the consolidated sludge samples collected from the Hanford K East Basin in March and April 1999. The consolidated sludge samples were collected to provide additional material needed for the evaluation and design of systems that will be used to manage the K Basin sludge (i.e., disposition the sludge to T Plant for interim storage). The analytical results given in this report add to the knowledge on the composition of the K Basin sludge and provide specific information on this sludge necessary to plan and understand subsequent process testing. The following analyses were performed: weight percent (wt%) solids determination; uranium analysis by kinetic phosphorescence; plutonium isotope analysis by extraction chromatographic separation followed by alpha energy analysis (AEA); gross beta analysis; gamma energy analysis (GEA); and metals analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES).

We investigated chemical etching as a possible means to mitigate the growth of UV laser-induced surface damage on fused silica. The intent of this work is to examine the growth behavior of existing damage sites that have been processed to remove the UV absorbing, thermo-chemically modified material within the affected area. The study involved chemical etching of laser-induced surface damage sites on fused silica substrates, characterizing the etched sites using scanning electron microscopy (SEM) and laser fluorescence, and testing the growth behavior of the etched sites upon illumination with multiple pulses of 351nm laser light. The results show that damage sites that have been etched to depths greater than about 9 {micro}m have about a 40% chance for zero growth with 1000 shots at fluences of 6.8-9.4 J/cm{sup 2}. For the etched sites that grow, the growth rates are consistent with those for non-etched sites. There is a weak dependence of the total fluorescence emission with the etch depth of a site, but the total fluorescence intensity from an etched site is not well correlated with the propensity of the site to grow. Deep wet etching shows some promise for mitigating damage growth in fused silica, but fluorescence does not …

The main research activity is to study various scattering processes which occur in H{sup -} collisions with atomic (specifically, noble gas and atomic hydrogen) targets in the intermediate energy region. These processes include: elastic scattering, single- and double-electron detachment, and target excitation/ionization.

This report presents the results of particle size analyses and calorimetry testing performed on selected single-pull sludge samples collected from the Hanford K East Basin between December 1998 and June 1999. The samples were collected as isolated cores predominantly from areas that had not been previously sampled (e.g., North Loadout Pit, Dummy Elevator Pit, Tech View Pit), or from areas in which the sludge composition had been altered since the last sampling (e.g., Weasel Pit). Particle size analyses were performed by washing wet sludge samples through a series of four sieves with openings of 250, 500, 1410, and 4000 {micro}m. The loaded sieves were weighed before and after drying to obtain wet and dry particle size distributions. Knowledge of the particle size distribution is needed to design and predict the performance of the systems that will be used to retrieve, transport, and recover sludge. Also, sieving provides an opportunity to observe the components in the sludge. For example, during sieving of the sludge sample from the North Loadout Pit, significant quantities of organic ion exchange beads were observed. The uranium metal content and the particle size of the uranium metal in the K Basin sludge will largely determine the chemical …

The purpose of this calculation is to determine the effects on long-term dose from disposing of selected U. S. Department of Energy (DOE) spent nuclear fuel (DSNF) in high integrity cans (HICs). The Civilian Radioactive Waste Management System Management and Operating contractor (CRWMS M&O) prepared the calculation as part of Performance Assessment (PA) activities for the DOE Yucca Mountain Project. DSNF encompasses approximately 2,500 MTHM (metric tons heavy metal) consisting of over 200 fuel types that have been categorized into 11 groups, referred to as Groups 1 to 11, to facilitate their performance assessment (DOE 1999a, Sec. 5). DSNF and high level waste (HLW) have been allocated 7,000 MTHM or 10% of the 70,000 MTHM of nuclear waste scheduled for disposal at Yucca Mountain (DOE 1999a, Sec. 8.1). Of the 7,000 MTHM, 2,333 will be DSNF, or 93% of all 2,500 MTHM of DSNF, and 4,667 MTHM equivalent will be HLW (DOE 1999a, Sec. 8.1). The DOE spent fuels selected for HIC disposal are those that are poorly characterized, fragmented, or damaged, and the HIC concept is intended to provide additional protection by delaying the radionuclide release to ensure that environmental and/or regulatory standards are met.

We present a comparison of two algorithms for solving the equations of unsteady inviscid compressible flow in a Eulerian frame. The first algorithm is a staggered grid Lagrange plus remap scheme. The Lagrange step in this method is a time-centered version of the scheme due to Tipton, while the remap step employs a variant of the corner transport upwind scheme due to Colella. The second algorithm is a spatially operator-split version of the higher-order Godunov scheme for gas dynamics due to Colella. They use the two methods to compute solutions to a number of one- and two-dimensional problems. The results show the accuracy and performance of the two schemes to be generally equivalent. In a 1984 survey paper by Woodward and Colella, staggered grid, Lagrange plus remap, artificial viscosity schemes did not compare favorably with cell-centered direct Eulerian higher-order Godunov methods. They examine, therefore, how certain features of the staggered grid scheme discussed here contribute to its improved accuracy. They show in particular that the improved accuracy of the present scheme is due in part to the use of a monotonic artificial viscosity in the Lagrange step and the use of an improved upwind method in the remap step.

Heat pipes are often proposed as cooling system components for small fission reactors. SAFE-300 and STAR-C are two reactor concepts that use heat pipes as an integral part of the cooling system. Heat pipes have been used in reactors to cool components within radiation tests (Deverall, 1973); however, no reactor has been built or tested that uses heat pipes solely as the primary cooling system. Heat pipe cooled reactors will likely require the development of a test reactor to determine the main differences in operational behavior from forced cooled reactors. The purpose of this paper is to describe the results of a systems code capable of modeling the coupling between the reactor kinetics and heat pipe controlled heat transport. Heat transport in heat pipe reactors is complex and highly system dependent. Nevertheless, in general terms it relies on heat flowing from the fuel pins through the heat pipe, to the heat exchanger, and then ultimately into the power conversion system and heat sink. A system model is described that is capable of modeling coupled reactor kinetics phenomena, heat transfer dynamics within the fuel pins, and the transient behavior of heat pipes (including the melting of the working fluid). The paper …

Diblock/silica films with multi-bilayer vesicular mesostructures of large characteristic length scales were synthesized through evaporation-induced self-assembly of PS-b-PEO. The present system is believed to be the first to yield diblock/silica films with multi-bilayer vesicular mesostructures through solvent evaporation-induced self-assembly (EISA). The ready formation in the present system is argued to be the polydispersity of polymer chains.

Transmission electron microscopy studies were applied to study GaN crystals doped with Mg. Both: bulk GaN:Mg crystals grown by a high pressure and high temperature process and those grown by metal-organic chemical-vapor deposition (MOCVD) have been studied. Structural dependence on growth polarity was observed in the bulk crystals. Spontaneous ordering (formation of polytypoids) was observed for growth in the N to Ga polar direction (N polarity). On the opposite site of the crystal (growth in the Ga to N polar direction) Mg-rich pyramidal defects with base on the basal planes and with walls inclined about 45O to these planes, empty inside (pinholes) were observed. A high concentration of these pyramidal defects was also observed in the MOCVD grown crystals. For samples grown with Mg delta doping planar defects were also observed especially at the early stages of growth followed by formation of pyramidal defects. TEM and x-ray studies of InxGa{sub 1{minus}x}N crystals for the range of 28-45% nominal In concentration shows formation of two sub-layers: strained and relaxed, with a much lower In concentration in the strained layer. Layers with the highest In concentration were fully relaxed.

This report documents the C version of the MCAPM (Monte Carlo All Particle Method) generator and collision physics library of subroutines. The Monte Carlo data generator (gen2000) reads cross sections and distributions that describe in-flight reactions from a binary library and creates an internal data library. The collision routines (bang2000) use this internal library to perform the physics of interaction of particles with the background material. Particles modeled with MCAPM-C are neutrons, charged particles (p, d, t, {sup 3}He, and {alpha}), and {gamma}'s. MCAPM-C is written in (nearly) standard C, and versions exist for Sun Solaris, Compaq Unix, IBM AIX, SGI Irix, and Linux. The library and its data files are installed on LC's Compass, TC, Forest, Blue, and Sky machines. This report describes the contents and format of the library, physics assumptions made, and the interface to the library's subroutines.

The effect of post-growth thermal treatment of the InAs/GaAs quantum dots is investigated in this work. The photoluminescence (PL) and transmission electron microscopy (TEM) studies of samples annealed at temperatures up to 950 degrees C are presented. A complete dissolution of QDs and substantial broadening of the wetting layer (WL) can be seen from TEM. We propose that the thermally induced modification of the WL rather than QDs can be responsible for a blue-shift and narrowing of PL peaks in structures containing InAs/GaAs QDs.

Since the discovery of surfactant-templated silica by Mobil scientists in 1992, mesostructured silica has been synthesized in various forms including thin films, powders, particles, and fibers. In general, mesostructured silica has potential applications, such as in separation, catalysis, sensors, and fluidic microsystems. In respect to these potential applications, mesostructured silica in the form of thin films is perhaps one of the most promising candidates. The preparation of mesostructured silica films through preferential solvent evaporation-induced self-assembly (EISA) has recently received much attention in the laboratories. However, no amphiphile/silica films with reverse mesophases have ever been made through this EISA procedure. Furthermore, templates employed to date have been either surfactants or poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymers, such as pluronic P-123, both of which are water-soluble and alcohol-soluble. Due to their relatively low molecular weight, the templated silica films with mesoscopic order have been limited to relatively small characteristic length scales. In the present communication, the authors report a novel synthetic method to prepare mesostructured amphiphilic/silica films with regular and reverse mesophases of large characteristic length scales. This method involves evaporation-induced self-assembly (EISA) of amphiphilic polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymers. In the present study, the PS-b-PEO diblocks are denoted as, for example, …

Rhodopseudomonas palustris is a common soil and water bacterium that makes its living by converting sunlight to cellular energy and by absorbing atmospheric carbon dioxide and converting it to biomass. This microbe can also degrade and recycle components of the woody tissues of plants, wood being the most abundant polymer on earth. Because of its intimate involvement in carbon management and recycling, R. palustris was selected by the DOE Carbon Management Program to have its genome sequenced by the Joint Genome Institute (JGI). This award provided funds for the preparation of R. palustris genomic DNA which was then supplied to the JGI in sufficient amounts to enable the complete sequencing of the R. palustris genome. The PI also supplied the JGI with technical information about the molecular biology of R. palustris.

An integrated approach, combining the continuum theory of sintering and Potts model based mesostructure evolution analysis, is used to solve the problem of bi-layered structure sintering. Two types of bi-layered structures are considered: layers of the same material with different initial porosity, and layers of two different materials. The effective sintering stress for the bi-layer powder sintering is derived, both at the meso- and the macroscopic levels. Macroscopic shape distortions and spatial distributions of porosity are determined as functions of the dimensionless specific time of sintering. The effect of the thickness of the layers on shrinkage, warpage, and pore-grain structure is studied. Ceramic ZnO powders are employed as a model experimental system to assess the model predictions.

TART2000 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo radiation transport code. This code can run on any modern computer. It is a complete system to assist you with input Preparation, running Monte Carlo calculations, and analysis of output results. TART2000 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART2000 is distributed on CD. This CD contains on-line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART2000 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART2000 and its data files.

The ENDF/B data library has recently been updated and is now freely available through the National Nuclear Data Center (NNDC), Brookhaven National Laboratory. This most recent library is identified as ENDF/B-VI, Release 7. Release 7 completely supersedes all preceding releases. As distributed the ENDF/B-VI, Release 7 data includes cross sections represented in the form of a combination of resonance parameters and/or tabulated energy dependent cross sections, nominally at 0 Kelvin temperature. For use in applications this library has been processed into the form of temperature dependent cross sections at eight temperatures between 0 and 2100 Kelvin, in steps of 300 Kelvin. At each temperature the cross sections are tabulated and linearly interpolable in energy. All results are in the computer independent ENDF/B-VI character format [1], which allows the data to be easily transported between computers. In its processed form this library is approximately 1.6 gigabyte in size and is distributed on three CDs.

Helium-cooled, refractory heat exchangers are now under consideration for first wall and divertor applications. These refractory devices take advantage of high temperature operation with large delta-Ts to effectively handle high heat fluxes. The high temperature helium can then be used in a gas turbine for high-efficiency power conversion. Over the last five years, heat removal with helium was shown to increase dramatically by using porous metal to provide a very large effective surface area for heat transfer in a small volume. Last year, the thermal performance of a bare-copper, dual-channel, helium-cooled, porous metal divertor mock-up was evaluated on the 30 kW Electron Beam Test System at Sandia National Laboratories. The module survived a maximum absorbed heat flux of 34.6 MW/m{sup 2} and reached a maximum surface temperature of 593 C for uniform power loading of 3 kW absorbed on a 2-cm{sup 2} area. An impressive 10 kW of power was absorbed on an area of 24 cm{sup 2}. Recently, a similar dual-module, helium-cooled heat exchanger made almost entirely of tungsten was designed and fabricated by Thermacore, Inc. and tested at Sandia. A complete flow test of each channel was performed to determine the actual pressure drop characteristics. Each channel was …

Forefront experiments in many scientific areas for which synchrotron sources provide sufficient flux are nonetheless hindered because detectors cannot collect data fast enough, do not cover sufficiently solid angle, or do no have adequate resolution. Overall, the synchrotron facilities, each of which represents collective investments from funding agencies and user institutions ranging from many hundreds of millions to more than a billion dollars, are effectively significantly underutilized. While this chronic and growing problem plagues facilities around the world, it is particularly acute in the United States, where detector research often has to ride on the coat tails of explicitly science-oriented projects. As a first step toward moving out of this predicament, scientists from the U.S. synchrotron facilities held a national workshop in Washington, DC, on October 30-31, 2000. The Workshop on Detectors for Synchrotron Research aimed to create a national ''roadmap'' for development of synchrotron-radiation detectors.

An investigation has been carried out on stainless steel to determine the important parameters that related the changes in pH around pits to the current coming from the pits. Potentiodynamic measurements at 1 mV/s were made on Type 302 stainless steel in agar containing 1M NaCl and a wide range pH indicator. Many pits suddenly appeared at the pitting potential, as indicated by the red, low pH region around the pits. Simulations of the changes in pH were based on diffusion from a point current source. The results also were considered in terms of the effects of a minimum detectable thickness of pH change within the gel.

A method for direct dc measurement of the Volta potential is presented. High intensity synchrotron x-ray beams were used to locally irradiate the atmosphere adjacent to the metal surface and produce a conducting path between a sample and a reference probe. The direct measurements of potential in the ionized air could be made at probe heights of around 1 mm compared to less than 0.1 mm for the Kelvin probe. The measurements were similar to traditional Kelvin probe measurements, but had a poorer spatial resolution. In contrast to the Kelvin probe methods, the approach described allows observation of the current as a function of impressed voltage. Methods to improve the special resolution of the technique and applications to corrosion under coating will be presented.

BNL E910 has measured strange baryon production as a function of collision centrality for 17.5 GeV/c p-Au collisions. Collision centrality is defined by v{sub 1} the mean number projectile-nucleon interactions estimated from the ''grey'' track multiplicity. The measured {Lambda} yield increases faster than the participant scaling expectation for v {le} 3 and then saturates. A simple parameterization of this dependence applied to nucleus-nucleus collisions reproduces the measured E866 km. and WA97 {Lambda} centrality dependent yields. The increase in {Lambda} production to v {le} 3 is also evident for {Lambda}s which are leading baryons, in disagreement with predictions from RQMD.

The Cold Vacuum Drying (CVD) Facility provides the required process systems, supporting equipment, and facilities needed for the conditioning of spent nuclear fuel (SNF) from the Hanford K-Basins prior to storage at the Canister Storage Building (CSB). The process water conditioning (PWC) system collects and treats the selected liquid effluent streams generated by the CVD process. The PWC system uses ion exchange modules (IXMs) and filtration to remove radioactive ions and particulate from CVD effluent streams. Water treated by the PWC is collected in a 5000-gallon storage tank prior to shipment to an on-site facility for additional treatment and disposal. The purpose of this sampling and analysis plan is to document the basis for achieving the following data quality objectives: (1) Measurement of the radionuclide content of the water transferred from the multi-canister overpack (MCO), vacuum purge system (VPS) condensate tank, MCO/Cask annulus and deionized water flushes to the PWC system receiver tanks. (2) Trending the radionuclide inventory of IXMs to assure that they do not exceed the limits prescribed in HNF-2760, Rev. 0-D, ''Safety Analysis Report for Packaging (Onsite) Ion Exchange Modules,'' and HNF-EP-0063 Rev. 5, ''Hanford Site Solid Waste Acceptance Criteria'' for Category 3, non-TRU, low level waste …