A 1200 channel Si(Li) detector system has been developed for transvenous coronary angiography experiments using synchrotron radiation. It is part of the synchrotron medical imaging facility at the National Synchrotron Light Source. The detector is made from a single crystal of lithium-drifted silicon with an active area 150 mm long {times} 11 mm high {times} 5 mm thick. The elements are arranged in two parallel rows of 600 elements with a center-to-center spacing of 0.25 mm. All 1200 elements are read out simultaneously every 4 ms. A Intel 80486 based computer with a high speed digital signal processing interface is used to control the beamline hardware and to acquire a series of images. The signal-to-noise, linearity and resolution of the system have been measured. Human images have been taken with this system.

Sandia National Laboratories, an 8500+ person, multiprogram research and development facility operated for the US Department of Energy, has over 400 research, development and applications scientists and engineers working on sensor technologies. Sandia`s 20 person Microsensors Research and Development Department has invented, developed and fielded sensor systems based on acoustic, fiber optic, and silicon microelectronic technologies. These sensors have been used for diverse applications inducting the monitoring of cleaning chemical concentrations in industrial process effluent streams, detection of explosive gas concentrations in aging industrial equipment, real-time measurements of fluid viscosity in equipment lubricants, and monitoring of contaminant concentration levels in ultrapure process gases. Representative sensor technologies available for technology transfer will be described including bulk acoustic wave resonators, surface acoustic wave devices, fiber optic micromirror sensors, and silicon microelectronic sensors.

Objects resonate at specific frequencies when mechanically excited. The specific resonance frequencies are a function of shape, size, material of construction, and contents of the object. This paper discusses the use of acoustic resonance spectroscopy (ARS) to monitor containers and detect tampering. Evaluation of this technique is based on simulated storage simulations. Although these simulations show promise for this application of ARS, final evaluation will require actual field testing.

The study of magnetic and biological materials which exhibit magnetic circular dichroism has created a demand for circularly polarized x-rays whose helicity may be switched between the right and left hand senses. At present, circularly polarized x-rays are obtained from storage ring bending magnets by accepting radiation from above and below the axis, but insertion device sources are desired for greater intensity. Planar helical undulators are magnetic insertion devices that generate helical magnetic fields. The charged particle beam executes a helical trajectory in the device, and produces elliptically polarized x-rays. The special case of circularly polarized x-rays is most in demand. We present here the design description of a new type of planar helical undulator, which we are constructing for the SPEAR storage ring at the Stanford Synchrotron Radiation Laboratory (SSRL). It comprises four rows of pure permanent magnet blocks, one row in each quadrant about the axis defined by the electron beam. Rows may be translated longitudinally with respect to each other to change the helicity of the magnetic field they create at the position of the beam. They may also be translated longitudinally to vary the energy of the x-rays emitted, unlike designs where this function is performed …

An analysis is carried out to determine the effects of the diffusional resistance on the rate of the adsorption of ammonia in an aqueous solution. A performance prediction model is developed to calculate the local rate of heat and mass transfer, including physical and thermodynamic property calculations of the mixture. An algorithm is developed for calculating the interfacial conditions. The local heat- and mass-transfer calculation is then incorporated into the performance prediction method for adsorption for a given geometry.

Today`s integrated circuits are so complex that it is often necessary to have access to the layouts and schematics when performing voltage contrast, cross sectioning, light emission, mechanical probing, optical beam induced current, and even simple SEM and Optical Examination. To deal with these issues, Sandia National Laboratories is developing an advanced failure analysis laboratory networking scheme to provide computer control, layout navigation, schematic navigation, and report generation on each of the major pieces of failure analysis equipment. This concept is known as an Integrated Diagnostic Environment or IDE. An integrated diagnostic environment is an environment where failure analysis equipment is computer-controlled and linked by a high speed network. The network allows CAD databases to be shared between instruments, improving the failure analyst`s productivity on each analysis task. At Sandia, we are implementing this concept using SUN Sparcstation computers running Schlumberger`s IDE software. To date, we have incorporated our electron beam prober and light emission system into the environment. We will soon add our scanning optical microscope and focused ion beam system and eventually add our optical microscope and microprobe station into the network. There are a number of issues to consider when implementing an Integrated Diagnostic Environment; these are …

Inspecting high-value structures, like bridges and buildings using Ground Penetrating Radar (GPR) is an application of the technology that is growing in importance. In a typical inspection application, inspectors use GPR to locate structural components, like reinforcing bars embedded in concrete, to avoid weakening the structure while collecting core samples for detailed inspection. Advanced GPR, integrated with imaging technologies for use as an NDE tool, can provide the capability to locate and characterize construction flaws and wear- or age-induced damage in these structures without the need for destructive techniques like coring. In the following sections, we discuss an important inspection application, namely, concrete bridge deck inspection. We describe an advanced bridge deck inspection system concept and provide an overview of a program aimed at developing such a system. Examples of modeling, image reconstruction, and experimental results are presented.

The objective of this procurement is to provide a test facility to support early commercialization of advanced fixed-bed coal gasification technology for electric power generation applications. The proprietary CRS Sirrine Engineers, Inc. PyGas{trademark} staged gasifier has been selected as the initial gasifier to be developed under this program. The gasifier is expected to avoid agglomeration when used on caking coals. It is also being designed to crack tar vapors and ammonia, and to provide an environment in which volatilized alkali may react with aluminosilicates in the coal ash thereby minimizing their concentration in the hot raw coal gas passing through the system to the gas turbine. This paper describes a novel, staged, airblown, fixed-bed gasifier designed to solve both through the incorporation of pyrolysis (carbonization) with gasification. It employs a pyrolyzer (carbonizer) to avoid sticky coal agglomeration which occurs in a fixed-bed process when coal is gradually heated through the 400{degrees}F to 900{degrees}F range. In a pyrolyzer, the coal is rapidly heated such that coal tar is immediately vaporized. Gaseous tars are then thermally cracked prior to the completion of the gasification process. During the subsequent endothermic gasification reactions, volatilized alkali can be chemically bound to aluminosilicates in (or added …

An overview is presented of research that focuses on slow flows of suspensions in which colloidal and inertial effects are negligibly small (Macrostatistical Hydrodynamics). First, we describe nuclear magnetic resonance imaging experiments to quantitatively measure particle migration occurring in concentrated suspensions undergoing a flow with a nonuniform shear rate. These experiments address the issue of how the flow field affects the microstructure of suspensions. In order to understand the local viscosity in a suspension with such a flow-induced, spatially varying concentration, one must know how the viscosity of a homogeneous suspension depends on such variables as solids concentration and particle orientation. We suggest the technique of falling ball viscometry, using small balls, as a method to determine the effective viscosity of a suspension without affecting the original microstructure significantly. We also describe data from experiments in which the detailed fluctuations of a falling ball`s velocity indicate the noncontinuum nature of the suspension and may lead to more insights into the effects of suspension microstructure on macroscopic properties. Finally, we briefly describe other experiments that can be performed in quiescent suspensions (in contrast to the use of conventional shear rotational viscometers) in order to learn more about the microstructure and boundary …

The Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory (LBL) is a 1.5 Gev synchrotron light source facility consisting of a 120 kev electron gun, 50 Mev linear accelerator, 1.5 Gev booster synchrotron, 200 meter circumference electron storage ring, and many photon beamline transport systems for research. Figure 1. ALS floor plan. Pairs of neutron and gamma radiation monitors are shown as dots numbered from 1 to 12. The Radiation Safety System for the ALS has been designed and built with a primary goal of providing protection against inadvertent personnel exposure to gamma and neutron radiation and, secondarily, to enhance the electrical safety of select magnet power supplies.

We have previously developed a model of alternating-phase focusing (APF) applicable to ion linacs comprised of short independently controlled cavities. The main beam dynamical aspects of APF are adequately described by four parameters: Equilibrium synchronous phase, phase modulation amplitude, length of APF period, and incremental energy gain. In this paper we report on an extension of the analysis to include simultaneous modulation of the accelerating field amplitude. Two additional parameters are included: Relative phase between the amplitude and phase modulation and magnitude of the amplitude modulation. The effects of amplitude modulation on the stable regions and longitudinal acceptance are discussed.

This paper describes fluid-structure-interaction and structure response analyses of a reactor vessel subjected to loadings associated with postulated accidents, using the improved hybrid Lagrangian-Eulerian code ALICE-II. The objective of the present analyses is to study the cover response and potential for missile generation in response to a fuel-coolant interaction in the core region. Three calculations were performed using the cover weight as a parameter. To study the effect of the cavity water outside the reactor vessel, vessel response calculations for both wet- and dry-cavity designs are compared. Results indicate that for all cases studied and for the design parameters assumed, the calculated cover displacements are all smaller than the bolts` ultimate displacement and no missile generation of the closure head is predicted. Also, solutions reveal that the cavity water of the wet-cavity design plays an important role of restraining the downward displacement of the bottom head. Based on these studies, the analyses predict that the structure integrity is maintained throughout the postulated accident for the wet-cavity design.

There are 81 dipole magnets contained in the storage ring at the Advanced Photon Source (APS). These magnets are connected in series and are energized by only one 12-phase power supply. The eighty-first magnet is located in a temperature-controlled room with an NMR probe to monitor the magnetic field in the magnet and provide a reference signal for correction of the field drift due to aging of the components. The current in the magnets will be held at 497 A. The required current stability of the power supply is {plus_minus}30 ppM, the current reproducibility is {plus_minus}50 ppM, and the current ripple is {plus_minus}400 ppM. The voltage required to maintain such a current in the magnets is about 1700 V. Different schemes for regulating current in the magnets are studied. Pspice software is used to simulate the behavior and the design of such a power supply under different conditions. The pros and cons of each scheme will be given and the proper power and regulating scheme will be selected.

A plasma thruster operating at high specific impulse ({ge} 3500 s) has been proposed to be based on electron-cyclotron resonance heating of whistler waves propagating on a plasma column on a magnetic hill. Calculations using a particle-in-cell code demonstrate that the distortion of the electron velocity distribution by the heating significantly reduces the flow of plasma up the field, greatly improving efficiency and reducing material interactions relative to a thermal plasma. These and other calculations are presented together with initial experiments on the plasma generated in the proposed device. The experiments are conducted in a magnetic field (3.3 {times} 10{sup {minus}2} T at resonance) and a magnetic mirror ratio of 5. Microwaves (0.915 GHz, <20 kW) are coupled to the plasma with a helical antenna. Vacuum field measurements are in good agreement with prediction. The desired plasma spatial distribution has not yet been achieved.

For the 1992 INNM Meeting, we reported on an automated system under development for measuring both concentration and enrichment of uranium in solutions. In this paper, we report on measurement methods, ysis algorithms, and performance of the delivered system. The uranium concentration is measured by a transmission-corrected x-ray fluorescence method. Cobalt-57 is the fluorescing source and a combined {sup 153}Gd and {sup 57}Co source is used for the transmission measurements. Corrections are made for both the absorption of the exciting {sup 57}Co gamma rays and the excited uranium x-rays. The {sup 235}U concentration is measured by a transmission-corrected method, which employs the 185.7-keV gamma ray of {sup 235}U and a transmission source of {sup 75}Se to make corrections for the self-absorption of the {sup 235}U gamma rays in the solution samples. Both measurements employ high-resolution gamma-ray spectrometry and use the same 50-m{ell} sample contained in a custom-molded, flat-bottomed, polypropylene bottle. Both measurements are intended for uranium solutions with concentrations {ge}0.1 g U/{ell} although at higher enrichments the passive measurement will be even more sensitive.

A hybrid bus powered by a diesel engine and a battery pack has been analyzed over an idealized bus-driving cycle in Chicago. Three hybrid configurations, two parallel and one series, have been evaluated. The results indicate that the fuel economy of a hybrid bus, taking into account the regenerative braking, is comparable with that of a conventional diesel bus. Life-cycle costs are slightly higher because of the added weight and cost of the battery.

Computer and network systems are available to attacks. Abandoning the existing huge infrastructure of possibly-insecure computer and network systems is impossible, and replacing them by totally secure systems may not be feasible or cost effective. A common element in many attacks is that a single user will often attempt to intrude upon multiple resources throughout a network. Detecting the attack can become significantly easier by compiling and integrating evidence of such intrusion attempts across the network rather than attempting to assess the situation from the vantage point of only a single host. To solve this problem, we suggest an approach for distributed recognition and accountability (DRA), which consists of algorithms which ``process,`` at a central location, distributed and asynchronous ``reports`` generated by computers (or a subset thereof) throughout the network. Our highest-priority objectives are to observe ways by which an individual moves around in a network of computers, including changing user names to possibly hide his/her true identity, and to associate all activities of multiple instance of the same individual to the same network-wide user. We present the DRA algorithm and a sketch of its proof under an initial set of simplifying albeit realistic assumptions. Later, we relax these assumptions …

This paper analyzes initial in-plant measurements made by active neutron multiplicity counting, a new technique currently under development for the assay of bulk uranium containing kilograms of {sup 235}U. The measurements were made at Savannah River and Y-12 using active well coincidence counters and prototype multiplicity electronics and software from Los Alamos. For one of the sets of highly enriched uranium samples measured to data, we improved the assay accuracy by an order-of-magnitude by adding the multiplicity analysis to the conventional coincidence analysis. This paper summarizes our results and describes areas where further work is needed.

The above-threshold ionization (ATI), a strong-field behavior, can be studied using kilohertz lasers. This paper reports a study of electron angular distributions (AD) for Xe and Kr excited by a 50 ps, 1.05 {mu}m strong field. ADs are presented for ATI orders up to 30 and show a new intensity-dependent structure. A physical picture is proposed that has its source in one-electron, and not two-electron, dynamics. 2 figs, 5 refs.

The utility of the arbitrary-Lagrangian-Eulerian (ALE) code format is evaluated in the context of use in simulating metal forming processes. Emphasis is on large deformation processes such as casting, forging and extrusion. The basic point at issue is whether the continual remapping capability inherent in the ALE approach can provide advantages relative to the more standard approach of using a Lagrangian mesh but allowing for isolated remeshing as required. A particular ALE implementation, ALE3D, is used as the basis for the discussion. Pros and cons for this approach are presented along with illustrations of its application to actual forming problems.

Automated analysis using pattern recognition and neural network software can help interpret data, call attention to potential anomalies, and improve safeguards effectiveness. Automated software analysis, based on pattern recognition and neural networks, was applied to data collected from a radiation core discharge monitor system located adjacent to an on-load reactor core. Unattended radiation sensors continuously collect data to monitor on-line refueling operations in the reactor. The huge volume of data collected from a number of radiation channels makes it difficult for a safeguards inspector to review it all, check for consistency among the measurement channels, and find anomalies. Pattern recognition and neural network software can analyze large volumes of data from continuous, unattended measurements, thereby improving and automating the detection of anomalies. The authors developed a prototype pattern recognition program that determines the reactor power level and identifies the times when fuel bundles are pushed through the core during on-line refueling. Neural network models were also developed to predict fuel bundle burnup to calculate the region on the on-load reactor face from which fuel bundles were discharged based on the radiation signals. In the preliminary data set, which was limited and consisted of four distinct burnup regions, the neural network …

A growing social awareness of the adverse impact of pollutants on our environment and the promulgation of environmental laws and regulations has recently stimulated the development of technologies for pollution abatement and hazardous waste destruction. Pulsed power shows strong promise for contributing to the development of innovative technologies aimed at these applications. At Los Alamos we are engaged in two projects which apply pulsed power technology to the environment: the use of relativistic electron beams and nonequilibrium plasmas for the destruction of hazardous organic compounds in aqueous-based and gaseous-based medial, respectively. Electron beams and nonequilibrium plasmas have also been applied to the treatment of flue gases such as SO{sub x} and NO{sub x} by other researchers. In this paper, we will describe our electron-beam and plasma experiments carried out on hazardous waste destruction. Additionally, we will describe the scaling of electron-beam and nonequilibrium plasma systems to industrial sizes, including discussions of electron accelerator architecture, comparison of continuous-duty versus repetitively pulsed accelerators, plasma-discharge modulators, and needed pulsed power technology development.

The high brightness and short pulse duration of soft x-ray lasers provide unique advantages for novel applications. Imaging of biological specimens using x-ray lasers has been demonstrated by several groups. Other applications to fields such as chemistry, material science, plasma diagnostics, and lithography are beginning to emerge. We review the current status of soft x-ray lasers from the perspective of applications, and present an overview of the applications currently being developed.

Thermomechanical models are being developed to support the design of an Exploratory Studies Facility (ESF) and a potential high-level nuclear waste repository at Yucca Mountain, Nevada. These models are used for preclosure design of underground openings, such as access drifts, emplacement drifts, and waste emplacement boreholes; and in support of postclosure issue resolution relating to waste canister performance, disturbance of the hydrological properties of the host rock, and overall system performance assessment. For both design and performance assessment, the purpose of using models in analyses is to better understand and quantify some phenomenon or process. Therefore, validation is an important process that must be pursued in conjunction with the development and application of models. The Site Characterization Plan (SCP) addressed some general aspects of model validation, but no specific approach has, as yet, been developed for either design or performance assessment models. This paper will discuss a proposed process for thermomechanical model validation and will focus on the use of laboratory and in situ experiments as part of the validation process. The process may be generic enough in nature that it could be applied to the validation of other types of models, for example, models of unsaturated hydrologic flow.