Spontaneous ordering of ternary alloys grown on misoriented substrates has been of recent interest. Ordering induced band gap reduction, and valence band splittings exhibiting novel polarization properties have been investigated by theory and experiment. This paper discusses polarized photomodulated reflectivity (PR) and photoluminescence (PL) studies of MOCVD grown InGaP{sub 2} epilayers lattice-matched to a GaAs substrate. These structures were grown on a (001) face with a niisorientation of two degrees along <110>. The high degree of ordering has enabled us to accurately measure the crystal field splitting and additional structure not reported in the PR spectra. For the electric field E parallel to [110] two features in the PR spectra are seen; for E {parallel}[110], however, additional features are observed. Comparison with spectra of disordered samples of the same alloy composition has enabled a determination of the band gap reduction due to ordering. Linewidths of the PR peaks are approximately 5--10 meV which has enabled us to study them in detail as a function of hydrostatic pressure at cryogenic temperatures. The pressure dependence is slightly sublinear with the first order term of 8--9 meV/kbar for pressures well below the l-X crossover. Also observed is the indirect level crossing which occurs …

With the importance of safeguards in production facilities, the Los Alamos National Laboratory Plutonium Facility has installed a neutron slab counter to facilitate the measurement of low-level waste packaged in 4 ft {times} 4 ft {times} 8 ft crates. In the past, oversized packages were measured by a gamma technique to assess holdup. The measurement was time-consuming and cumbersome, and the efficiency was questionable. The slab counter has alleviated the time and efficiency problems of the gamma measurement. The counter consists of four slab counters, each slab containing twenty 60-in. long helium-3 tubes embedded in 3.5 in. thick polyethylene slab. The detectors are shielded from room background by an additional 3.5 in. of polyethylene. The 4 ft 6 in. by 7 ft 6 in by 8 in. steel encased slabs are arranged around a 4 ft 6 in. {times} 22 ft conveyor system with two slabs on each side of the conveyor. The slabs are located on one end of the conveyor, with the end open to facilitate waste crate loading by forklift. The system was calibrated with a {sup 252}Cf source and placed in various locations throughout a mock waste crate. The mock calibration waste crate can be loaded …

Several high quality (RE)Ba{sub 2}Cu{sub 3}O{sub 7-x} single crystals with RE = Y, Yb and Dy, with varying amounts of Au- and Al-impurities have been investigated by SQUID magnetometry. All samples show fishtail behavior. Differences in the sample preparation only influence the position of the maximum in J{sub c}. The authors conclude that the fishtail phenomenon is not a material specific property, but a generally occurring property of the flux line lattice.

The Department of Energy (DOE) mission is changing due to the number of nuclear weapon reductions by the United States and the former Soviet Union with long-term storage requirements for DOE sites increasing. New technology to ensure the integrity of special nuclear material (SNM) in storage is available to sites to supplement manual physical inventories. This allows them to decrease operating costs while keeping radiation exposure at minimal levels. We have developed a generic, real time, personnel tracking and material monitoring system named PAMTRAK. Such a system can significantly reduce the number of required, manual physical inventories at DOE sites while increasing assurance that an insider has not diverted or stolen material. Until recently Pamtrak used only material monitoring devices that provided location/containment attributes. However, Westinghouse Electric Corp. and Metrox, Inc. have recently developed hard-wired item/material attribute systems that monitor both temperature and weight. We have incorporated both of these systems into PAMTRAK. If a site employed one of these item/material attribute systems, it could decrease its manual inventory frequency to three years. This paper describes how a site might implement such a system to meet the DOE`s requirements.

The need for a useful nuclear materials database to assist in the management of nuclear materials within the Department of Energy (DOE) Weapons Complex is becoming significantly more important as the mission of the DOE Complex changes and both international safeguards and storage issues become drivers in determining how these materials are managed. A well designed nuclear material inventory database can provide the Nuclear Materials Manager with an essential cost effective tool for timely analysis and reporting of inventories. This paper discusses the use of databases as a management tool to meet increasing requirements for accurate and timely information on nuclear material inventories and related information. From the end user perspective, this paper discusses the rationale, philosophy, and technical requirements for an integrated database to meet the needs for a variety of users such as those working in the areas of Safeguards, Materials Control and Accountability (MC&A), Nuclear Materials Management, Waste Management, materials processing, packaging and inspection, and interim/long term storage.

In order to carry out a program of ICRF experiments in deuterium- tritium plasmas on the TFTR device a series of technical improvements have been made to the ICRF system. These improvements allow more flexible and reliable operation of the system which is crucial for the limited number of tritium discharges available. During the last year circuitry has been installed to feedback the plasma position on antenna loading, to lock the phase between antenna elements, and to detect arcs from the second harmonic content of antenna signals.

Verification measurements may be used to help ensure nuclear criticality safety when burnup credit is applied to spent fuel transport and storage systems. The FORK system measures the passive neutron and gamma-ray emission from spent fuel assemblies while in the storage pool. It was designed at Los Alamos National Laboratory for the International Atomic Energy Agency safeguards program and is well suited to verify burnup and cooling time records at commercial Pressurized Water Reactor (PWR) sites. This report deals with the application of the FORK system to burnup credit operations.

The Safeguards Information Management System initiative is a program of the Department of Energy`s (DOE) Office of Arms Control and Nonproliferation aimed at supporting the International Atomic Energy Agency`s (IAEA) efforts to strengthen safeguards through the enhancement of information management capabilities. The DOE hopes to provide the IAEA with the ability to correlate and analyze data from existing and new sources of information, including publicly available information, information on imports and exports, design information, environmental monitoring data, and non-safeguards information. The first step in this effort is to identify and define IAEA requirements. In support of this, we have created a users` requirements document based on interviews with IAEA staff that describes the information management needs of the end user projected by the IAEA, including needs for storage, retrieval, analysis, communication, and visualization of data. Also included are characteristics of the end user and attributes of the current environment. This paper describes our efforts to obtain the required information. We discuss how to accurately represent user needs and involve users for an international organization with a multi-cultural user population. We describe our approach, our experience in setting up and conducting the interviews and brainstorming sessions, and a brief discussion of …

The Integral Fast Reactor (IFR)--consisting of a metal fueled and liquid metal cooled reactor together with an attendant fuel cycle facility (FCF)--is currently undergoing a phased demonstration of the closed fuel cycle at Argonne National Laboratory. The recycle technology is pyrometalurgical based with incomplete fission product separation and all transuranics following plutonium for recycle. The equipment operates in batch mode at 500 to 1,300 C. The materials are highly radioactive and pyrophoric, thus the FCF requires remote operation. Central to the material control and accounting system for the FCF are the balances for mass measurements. The remote operation of the balances limits direct adjustment. The radiation environment requires that removal and replacement of the balances be minimized. The uniqueness of the facility precludes historical data for design and performance assessment. To assure efficient operation of the facility, the design of the measurement control system has called for procedures which assess the performance of the balances in great detail and will support capabilities for the correction of systematic changes in the performance of the balances through software.

Two-pion correlation functions have been studied using the E814 apparatus in 14.6 A{center_dot}GeV/c {sup 28}Si + Pb central collisions. Results of the correlation functions for pions from the RQMD event generator are compared to the data and show that a source with RMS radius of 8.3 fm is compartable with the experimental data.

NATO and former Warsaw Pact nations have agreed to allow overflights of their countries in the interest of easing world tension. The United States has decided to implement two C-135 aircraft with a Synthetic Aperture Radar (SAR) that has a 3-meter resolution. This work is being sponsored by the Defense Nuclear Agency (DNA) and will be operational in Fall 1995. Since the SAR equipment must be exportable to foreign nations, a 20-year-old UPD-8 analog SAR system was selected as the front-end and refurbished for this application by Loral Defense Systems. Data processing is being upgraded to a currently exportable digital design by Sandia National Laboratories. Amplitude and phase histories will be collected during these overflights and digitized on VHS cassettes. Ground stations will use reduction algorithms to process the data and convert it to magnitude-detected images for member nations. System Planning Corporation is presently developing a portable ground station for use on the demonstration flights. Aircraft integration into the C-135 aircraft is being done by the Air Force at Wright-Patterson AFB, Ohio.

We describe water vapor profile measurements made with the Sandia Raman lidar. The goal of this study is to determine the effect of convection on the upper tropospheric moisture budget. At present, considerable controversy exists over the nature of the vertical redistribution of water vapor in a changing climate, and particularly the distribution of water vapor in the upper troposphere. Although upper tropospheric moisture concentrations are several orders of magnitude lower than those near the surface, upper tropospheric moisture exerts an important influence on climate. On a per-molecule basis, greenhouse absorption due to water vapor is about one hundred times more effective at high altitudes than at low altitudes. Several one-dimensional radiative convective models have been used to demonstrate the importance of upper tropospheric moisture on climate. What these models show is that for a given fractional increase in water vapor at a given altitude the response or change in surface temperature is qualitatively the same. Understanding upper tropospheric moistening processes are therefore of prime importance in addressing the water vapor feedback question. The goal of this study is to determine the upper tropospheric moisture budget associated with convective events, and in particular to extend process models to higher altitudes …

A new design of jet grouting tool that can be guided by horizontal well casings and that operates in the horizontal plane has been used for the in situ placement of grout and construction of a prototype horizontal barrier that is free of windows. Jet grouting techniques have been advanced to permit construction of horizontal barriers underneath contaminated soil without having to excavate or disturb the waste. The paper describes progress on the Fernald Environmental Restoration Management Corporation (FERMCO) In Situ Land Containment Project which is sponsored by the US Department of Energy`s (DOE) Office of Technology Development (OTD) for DOE`s Fernald Environmental Management Project (FEMP). The Fernald project is to demonstrate a novel, enabling technology for the controlled underground placement of horizontal panels of grout, and the joining of adjacent panels to construct practical, extensive barriers. Construction strategy, equipment mechanics and operating details of this new method are described.

The Hanford Site Permanent Isolation Barrier Development Program is developing an in-place disposal capability for low-level nuclear waste for the US Department of Energy at the Hanford Site in southeastern Washington State. Layered earthen and engineered barriers are being developed that will function in what is currently a semiarid environment (mean annual precipitation and temperature of 16 cm and 11.8{degrees}C, respectively) for at least 1,000 yr by limiting the infiltration of water through the waste. The Long-Term Climate Change Task has specific goals of (1) obtaining defensible probabilistic projections of the long-term climate variability in the Hanford Site region at many different time scales into the future; (2) developing several test-case climate scenarios that bracket the range of potential future climate, including both greenhouse warming and cycling into another ice age; and (3) using the climate scenarios both to test and to model protective barrier performance. Results from the Carp Lake Pollen Coring Project indicate that for the last approximately 100,000 yr the Columbia River Basin`s long-term range of mean annual precipitation ranged from 25%--50% below to 28% above modern levels, while temperature has ranged from 7{degrees}C--10{degrees}C below to 2{degrees}C above modern levels. This long record provides confidence that such …

The DOE has a number of sites where wastes can potentially leak into the ground and escape into the environment. Both the DOE and others are faced with a need to control a wide variety of pollutants on land: leaking underground storage tanks, unstabilized soluble wastes entering the groundwater, leachates from dump sites and other sources. Current technologies require either removal and repackaging of the waste from its existing location or, the ability to tie vertical barrier walls into an underlying impermeable layer to contain leaking wastes. Necessary elements in control are land containment systems capable of completely surrounding and holding the contamination until it is removed, stabilized and/or treated in situ. Horizontal barrier placement technology as currently practiced is not highly developed. A search of the barrier industry indicates that no other existing/developed technique is as capable as the innovative horizontal grout barrier method promises to be in providing means for vertical containment of preexisting land disposed materials. The primary competitive technologies are triple rod jet grouting and freeze walls.

With the completion of the AGS rf upgrade, and the implementation of a transition {open_quotes}jump{close_quotes}, all of accelerator systems were in place in 1994 to allow acceleration of the proton intensity available from the AGS Booster injector to AGS extraction energy and delivery to the high energy users. Beam commissioning results with these new systems are presented. Progress in identifying and overcoming other obstacles to higher intensity are given. These include a careful exploration of the stopband strengths present on the AGS injection magnetic porch, and implementation of the AGS single bunch transverse dampers throughout the acceleration cycle.

There are numerous hazardous waste sites under the jurisdiction of the US Department of Energy (DOE). To assist the cleanup of these sites in a more consistent, timely, and cost-effective manner, the Remedial Action Assessment System (RAAS) is being developed by the Pacific Northwest Laboratory (PNL). RAAS is a software tool designed to automate the initial technology selection within the remedial investigation/feasibility study (RI/FS) process. The software does several things for the user: (1) provides information about available remedial technologies, (2) sorts possible technologies to recommend a list of technologies applicable to a given site, (3) points out technical issues that may prevent the implementation of a technology, and (4) provides an estimate of the effectiveness of a given technology at a particular site. Information from RAAS can be used to compare remediation options and guide selection of technologies for further study.

The objective of this research is a doubling of the current density of the molten carbonate fuel cell (MCFC) from the present value of 1600A/m{sup 2} to 3200 A/m{sup 2} and a similar increase in the volumetric power density. This project is linked to other projects concerning MCFCs (one on the multiply manifolded MCFCs, the other on lithium ferrate and lithium cobaltate cathodes for MCFCs).

Narrow peaks have been observed at GSI Darmstadt in the energy spectra of positrons and sum-energy spectra of positron-electron pairs, produced in collisions of very heavy ions. To date, there is no satisfactory explanation of the origin of these lines although many differing models have been proposed. In this contribution, the authors describe the features of a new experiment aimed at the study of the line phenomenon and present the results of their first experiments. The specific goals of their experiment are to clarify the experimental situation regarding the lines through high-resolution, high-statistics data and, by direct measurement of the vector momenta of the peak pairs, to determine their kinematics.

The molecular-scale species distributions and intermediate-scale structure of silicate sols influence the microstructures of the corresponding thin films prepared by dip-coating. Using multi-step hydrolysis procedures, the authors find that, depending on the sequence and timing of the successive steps, the species distributions (determined by {sup 29}Si NMR) and intermediate scale structure (determined by SAXS) can change remarkably for sols prepared with the same nominal composition. During film formation, these kinetic effects cause differences in the efficiency of packing of the silicate species, leading to thin film structures with different porosities.

Effect of environmental conditions on cubic boron nitride (cBN) film adhesion to silicon substrates was studied. cBN films were deposited onto (100)-oriented silicon substrates by ion-assisted pulsed laser deposition. Irradiating ions were mixtures of nitrogen with argon, krypton, and xenon. Under room-ambient conditions, the films delaminated in the following time order: N/Xe, N/Kr, and N/Ar. cBN films deposited using N/Xe ion-assisted deposition were exposed to four environmental conditions for several weeks: a 1-mTorr vacuum, high humidity, dry oxygen, and dry nitrogen. Films exposed to the humid environment delaminated whereas those stored under vacuum or in dry gases did not. Films stored in dry nitrogen were removed after nearly two weeks and placed in the high-humidity chamber; these films subsequently delaminated within 14 hours.

An input shaping scheme originally used to slew flexible beams via a tabletop D.C. motor is modified for use with an industrial-type, hydraulic-drive robot. This trajectory generation method was originally developed to produce symmetric, rest-to-rest maneuvers of flexible rotating rods where the angular velocity vector and gravitational vector were collinear. In that configuration, out-of-plane oscillations were excited due to centripetal acceleration of the rod. The bang-coast-bang acceleration profile resulted in no oscillations in either plane at the end of the symmetric slew maneuver. In this paper, a smoothed version of the bang-coast-bang acceleration is used for symmetric maneuvers where the angular velocity vector is orthogonal to the gravitational vector. Furthermore, the hydraulic robot servo dynamics are considered explicitly in determining the input joint angle trajectory. An instrumented mass is attached to the tip of a flexible aluminum rod. The first natural frequency of this system is about 1.0Hz. Joint angle responses obtained with encoder sensors are used to identify the servo actuator dynamics.

We have begun to quantify the ability of acoustic resonance spectroscopy (ARS) to detect the removal and replacement of the lid of a simulated special nuclear materials drum. Conceptually, the acoustic spectrum of a container establishcs a baseline fingerprint, which we refer to as an intrinsic seal, for the container. Simply removing and replacing the lid changes some of the resonant frequencies because it is impossible to exactly duplicate all of the stress patterns between the lid and container. Preliminary qualitative results suggested that the ARS intrinsic seal could discriminate between cases where a lid has or has not been removed. The present work is directed at quantifying the utility of the ARS intrinsic seal technique, including the technique`s sensitivity to ``nuisance`` effects, such as temperature swings, movement of the container, and placement of the transducers. These early quantitative tests support the potential of the ARS intrinsic seal application, but also reveal a possible sensitivity to nuisance effects that could limit environments or conditions under which the technique is effective.

In this paper we discuss the system design and ongoing efforts to characterize the machine physics and operating properties of the Skua fast burst assembly. The machine is currently operating up to prompt critical while we await approval for super-prompt burst operations. Efforts have centered on characterizing neutron kinetic properties, comparing calculated and measured temperature coefficients and power distributions, improving the burst reproducibility, examining the site-wide dose characteristics, and fitting the machine with cooling and filtration systems.