We shall consider an interesting topic relating nonlinear optics and organic materials: how nonlinear optics can be used to study organic materials. One of the main differences between linear and nonlinear responses of a medium to incoming radiation is in their symmetries. It leads to the possibility that some properties of the medium could be more sensitively probed by nonlinear, rather than linear, optical means, or vise versa. A well-known example is that some vibrational modes of a medium could be Raman-active but infrared-inactive, and would be more readily observed by Raman scattering, which is a two-photon transition process. In this paper, we shall discuss, with the help of three examples, how we can use second harmonic generation (SHG) and sum frequency generation (SFG) to obtain unique information about a material. We shall focus on thin films, surfaces, and interfaces.

A Portable Laser Laboratory (PLL) is being designed and built for the CALIOPE Program tests which will begin in October of 1994. The PLL is designed to give maximum flexibility for evolving laser experiments and can be readily moved by loading it onto a standard truck trailer. The internal configuration for the October experiments will support a two line DIAL system running in the mid-IR. Brief descriptions of the laser and detection systems are included.

In the Stanford Linear Collider the energy spread of the bunches at the end of the linac is dominated by longitudinal wakefields. A short, high current bunch with a Gaussian shape will produce a double-horned energy distribution. It can be shown that certain charge distributions with a sharp rise time (about rectangular or half-Gaussian) will give no additional energy spread due to the linac, since the generated wakefield and the rf-curvature cancel each other exactly. In this paper different methods are presented on how to achieve such distributions by using non-linear dependences in the RTL (Ring-To-Linac) compression region. A simple and effective method to achieve such a distribution is by over-compression. When not fully compressing the bunch, there are two settings of the compressor voltage, under and over-compression, which give the same core bunch length in the linac. By switching from the under to the over-compressed setting, the tails are reduced from more than Gaussian to less than Gaussian beam tails. This results in a roughly rectangular shape which will give the wakefield-rf cancellation. Simulations, measurements and their implications are discussed.

While the much discussed lepton-number violating process e{sup {minus}}e{sup {minus}} {yields} W{sub R}{sup {minus}}W{sub R}{sup {minus}} provides an excellent probe of both the Majorana nature of the right-handed neutrino and the symmetry breaking sector of the Left-Right Symmetric Model, it is likely that W{sub R}`s are too massive to be pair produced at the NLC with {radical}s in the 1-1.5 TeV range. The author is thus lead to consider the single W{sub R} production process e{sup {minus}}e{sup {minus}} {yields} W{sub R}{sup {minus}}(W{sub R}{sup {minus}}){sup *} {yields} W{sub R}{sup {minus}} + jj in order to expand the collider`s kinematic reach. After pointing out that W{sub R}`s with masses of order 1 TEV may be missed by future hadron collider searches, the author demonstrates that this three-body process possesses a significant cross section, of order several fb, at the NLC with {radical}s in the range above. The angular distribution of the produced W{sub R}`s is shown to be essentially flat and the potential backgrounds from standard model processes are shown to be small.

It has been recognized since the beginning of the CALIOPE remote sensor development program that performance criteria must be developed to measure progress and efficacy, then prototype sensors must be evaluated against them. Much of the early evaluation may be carried out cost effectively in the laboratory and at field ranges located near each of the participating national laboratories. However, sensor performance is expected to be degraded by many factors in the field at remote sites and the extent of that degradation must be quantified before instruments can be designed and constructed for international deployment. LLNL proposed a series of field tests for this purpose at the Remote Sensor Test Range (RSTR) located at the Nevada Test Site (NTS). Well-controlled gas plumes containing mixtures of important species at known concentration would be released to the open atmosphere and used as targets for the prototype remote sensors. The plume dimensions and gas concentrations will be well diagnosed to provide {open_quotes}ground truth{close_quotes}. Gases selected as targets will, in the beginning, be chosen to optimize instrument performance in the field and identifying those factors that limit performance. The initial experiments will use ground based-instruments observing the target plumes from relatively close range. Field …

The strong coupling {alpha}{sub s} has been measured using hadronic decays of Z{sup 0} bosons collected by the SLD experiment at SLAC. The data were compared with QCD predictions both at fixed order, O({alpha}{sub s}{sup 2}), and including resummed analytic formulae based on the leading and next-to-leading logarithm approximation. The authors studied event shapes, jet rates, particle correlations, and energy fraction and checked the consistency between {alpha}{sub s} extracted from these different measures. Combining all results they obtain {alpha}{sub s}(M{sub Z{sup 0}}{sup 2}) = 0.120 {+-} 0.003(exp.) {+-} 0.009(theor.), where the dominant uncertainty in {alpha}{sub s} is from uncalculated higher order contributions.

Tritium behavior in ceramic breeder blankets is a key design issue for this class of blanket because of its impact on safety and fuel self-sufficiency. Over the past 10-15 years, substantial theoretical and experimental efforts have been dedicated world-wide to develop a better understanding of tritium transport in ceramic breeders. Models that are available today seem to cover reasonably well all the key physical transport and trapping mechanisms. They have allowed for reasonable interpretation and reproduction of experimental data and have helped in pointing out deficiencies in material property data base, in providing guidance for future experiments, and in analyzing blanket tritium behavior. This paper highlights the progress in tritium modeling over the last decade. Key tritium transport mechanisms are briefly described along with the more recent and sophisticated models developed to help understand them. Recent experimental data are highlighted and model calibration and validation discussed. Finally, example applications to blanket cases are shown as illustration of progress in the prediction of ceramic breeder blanket tritium inventory.

A new quark potential model, the quark delocalization and color screening model, is used for a systematic search of dibaryon candidates in the u, d and s three flavor world. The color screening results from unquenched lattice gauge calculations and quark delocalization similar to electron delocalization in molecular physics are included. Flavor symmetry breaking and channel coupling effects are studied. The model is constrained not only by the baryon ground state property but also by the N-N scattering phase shifts. The deuteron and the zero energy di-nucleon resonance are reproduced qualitatively. The model predicts that there might be two kinds of dibaryon states. Possible high spin dibaryou resonances are emphasized.

Major initiatives are underway within DOE to recycle large volumes of scrap material generated during cleanup of the DOE Weapons Complex. These recycling initiatives are driven not only by the desire to conserve natural resources, but also by the recognition that shallow level burial is not a politically acceptable option. The Fernald facility is in the vanguard of a number of major DOE recycling efforts. These early efforts have brought issues to light that can have a major impact on the ability of Fernald and other major DOE sites to expand recycling efforts in the future. Some of these issues are; secondary waste deposition, title to material and radioactive contaminants, mixed waste generated during recycling, special nuclear material possession limits, cost benefit, transportation of waste to processing facilities, release criteria, and uses for beneficially reused products.

The superconducting Tevatron accelerator at Fermilab has reached its eleventh year of operation since being commissioned in 1983. Last summer, four significant upgrades to the cryogenic system became operational which allow Tevatron operation at higher energy. This came after many years of R&D, power testing in sectors (one sixth) of the Tevatron, and final system installation. The improvements include the addition of cold helium vapor compressors, supporting hardware for subatmospheric operation, a new satellite refrigerator control system, and a higher capacity central helium liquefier. A description of each cryogenic upgrade, commissioning experience, and attempts to increase the energy of the Tevatron are presented.

We shall discuss the effects of conductor geometry on source localization for applications in epilepsy studies. The most popular conductor model for clinical MEG studies is a homogeneous sphere. However, several studies have indicated that a sphere is a poor model for the head when the sources are deep, as is the case for epileptic foci in the mesial temporal lobe. We believe that replacing the spherical model with a more realistic one in the inverse fitting procedure will improve the accuracy of localizing epileptic sources. In order to include a realistic head model in the inverse problem, we must first solve the forward problem for the realistic conductor geometry. We create a conductor geometry model from MR images, and then solve the forward problem via a boundary integral equation for the electric potential due to a specified primary source. One the electric potential is known, the magnetic field can be calculated directly. The most time-intensive part of the problem is generating the conductor model; fortunately, this needs to be done only once for each patient. It takes little time to change the primary current and calculate a new magnetic field for use in the inverse fitting procedure. We present …

The annealing behaviour open-volume defects introduced in Si(l00) crystals during fluorine implantation and their role in the surface-oriented diffusion of F impurities were investigated by variable-energy positron beam depth profiling. The defects become mobile and undergo recovery at temperatures well below the onset of fluorine diffusion at 550{degree}C as seen by secondary ion mass spectroscopy (SIMS). The results suggests that after irradiation and annealing the F occupies substitutional sites to which positrons are insensitive. The anomalous F diffusion seen in SIMS has been explained through a two-step diffusion mechanism, in which the diffusion kinetics is determined by dissociation of the substitutional F into an interstitial F and a vacancy, followed by their rapid diffusion to the surface.

Charged-particles produced by neutron bombardment of selected targets with Z=5 through 53 have been studied for neutron energies from 1 MeV to about 100 MeV using the spallation neutron source at WNR/LAMPF. Particle detection with energy measurement and particle identification is accomplished by two-element {Delta}E-E counters, three-element {Delta}E{sub l}-{Delta}E{sub 2}-E counters or with pulse-shape discrimination using scintillators directly in the neutron beam. The experimental techniques for these measurements are described and comparisons made among the different approaches. This presentation introduces five papers contributed to this conference.

Internal corrosion in semiconductor gas delivery systems may lead to increased particle counts in downstream fabrication tools and to catastrophic failure of the delivery system itself. The problem is particularly acute since, once the corrosion begins, it becomes a moisture reservoir to further damage the system. To keep gas systems as moisture free as possible semiconductor manufacturers employ drying filters, usually located just after the source of the process gas. Even so, the piping for corrosive gases may need to be rebuilt every few years. Careful monitoring of the moisture in the process gases can provide valuable information about the state of the gas handling system and its effect on the process integrity. Presently there are several technologies costing $50K or less that are capable of detecting trace water vapor as low as 50 ppb in N{sub 2}. However, no one type of instrument has achieved universal acceptance. In particular, all have limited compatibility with corrosive gases such as HCl and HBr. The goal of this project is to develop an in-line instrument based on infrared spectroscopy for this purpose. Earlier results leave no doubt that FTIR spectroscopy can be successfully used for trace water detection. However, important questions regarding …

The American Association for the Advancement of Science sponsored a seminar during September 1993, in Kiev, Ukraine, entitled ``Toward a Nuclear Free Future -- Barriers and Problems.`` It brought together Ukrainians, Belarusians, and Americans to discuss the legal, political, safeguards and security, economic, and technical dimensions of nuclear weapons dismantlement and destruction. US representatives initiated discussions on legal and treaty requirements and constraints, safeguards and security issues surrounding dismantlement, storage and disposition of nuclear materials, warhead transportation, and economic considerations. Ukrainians gave presentations on arguments for and against the Ukraine keeping nuclear weapons, Ukrainian Parliament non-approval of START I, alternative strategies for dismantling silos and launchers, and economic and security implications of nuclear weapons removal from the Ukraine. Participants from Belarus discussed proliferation and control regime issues, This paper will highlight and detail the issues, concerns, and possible impacts of the Ukraine`s dismantlement of its nuclear weapons.

All prior interferometric SAR imaging experiments to date dealt with pairwise processing. Simultaneous image collections from two antenna systems or two-pass single antenna collections are processed as interferometric pairs to extract corresponding pixel by pixel phase differences which encode terrain elevation height. The phase differences are wrapped values which must be unwrapped and scaled to yield terrain height. We propose two major classes of techniques that hold promise for robust multibaseline (multiple pair) interferometric SAR terrain elevation mapping. The first builds on the capability of a recently published method for robust weighted and unweighted least-squares phase unwrapping, while the second attacks the problem directly in a maximum likelihood (ML) formulation. We will provide several examples (actual and simulated SAR imagery) that illustrate the advantages and disadvantages of each method.

During the 5-day meeting, 112 half-hour talks on current research topics were presented. Session topics included: fluids, domain decomposition, iterative methods, Basics I and II, adaptive methods, nonlinear filtering, CFD I, II, and III, applications, transport, algebraic solvers, supercomputing, and student paper winners.

In situ long-term low-temperature (LTLT) gas phase decontamination is being developed and demonstrated at the K-25 site as a technology that has the potential to substantially lower these costs while reducing criticality and safeguards concerns and worker exposure to hazardous and radioactive materials. The objective of gas phase decontamination is to employ a gaseous reagent to fluorinate nonvolatile uranium deposits to form volatile UF{sub 6}, which can be recovered by chemical trapping or freezing. The LTLT process permits the decontamination of the inside of gas-tight GDP process equipment at room temperature by substituting a long exposure to subatmospheric ClF{sub 3} for higher reaction rates at higher temperatures. Laboratory-scale experiments have demonstrated the feasibility of using LTLT gas phase decontamination with ClF{sub 3} to remove uranium deposits from this equipment. A mobile gas phase system is being designed to demonstrate the decontamination process on a full scale. If used to decontaminate the GDPs, the LTLT process would use large amounts of ClF{sub 3} and exhaust large volumes of by-product gases (ClF, C1O{sub 2}F, etc.). Initially, the excess ClF{sub 3} and reaction byproducts will be destroyed in a KOH scrubber. This paper describes a proposed system that could recover the excess ClF{sub …

Nuclear Materials Safeguards (also known as Material Control and Accountability or MC&A) and Nuclear Materials Management as practiced within the US Department of Energy (DOE) are separate, but related disciplines with differing goals and objectives. Safeguards and Nuclear Materials Management are closely related through the common use of transaction and inventory reporting data from the Nuclear Materials Management and Safeguards System (NMMSS). Adherence to Nuclear Materials management principals may enhance Nuclear Materials Safeguards, and has the potential to result in savings for both program and safeguards costs. Both the Safeguards and Nuclear Materials Management Programs for the Chicago Operations Office are administered by the Safeguards and Security Division, Safeguards Branch. This paper discusses Safeguards and Materials Management issues within the Chicago Operations Office, some of which relate to problems faced by the DOE complex as a whole.

This paper describes the electrical design and operation of a high power modulator system implemented for the Los Alamos Plasma Source Ion Implantation (PSII) facility. To test the viability of the PSII process for various automotive components, the modulator must accept wide variations of load impedance. Components have varying area and composition which must be processed with different plasmas. Additionally, the load impedance may change by large factors during the typical 20 uS pulse, due to plasma displacement currents and sheath growth. As a preliminary design to test the system viability for automotive component implantation, suitable for a manufacturing environment, circuit topology must be able to directly scale to high power versions, for increased component through-put. We have chosen an evolutionary design approach with component families of characterized performance, which should Ion result in a reliable modulator system with component lifetimes. The modulator utilizes a pair of Litton L-3408 hollow beam amplifier tubes as switching elements in a ``hot-deck`` configuration. Internal to the main of planar triode hot deck, an additional pair decks, configured in a totem pole circuit, provide input drive to the L-3408 mod-anodes. The modulator can output over 2 amps average current (at 100 kV) with 1 …

Computer based three-dimensional modeling is a powerful tool used for visualizing and interpreting environmental data collected at the Savannah River Site (SRS). Three-dimensional modeling was used to image and interpret subsurface spatial data, primarily, changes in the movement, the accumulation, and the depletion of contaminants at the Integrated Demonstration Site (IDS), a proving ground for experimental environmental remediation technologies. Three-dimensional models are also educational tools, relaying complex environmental data to interested non-technical individuals who may be unfamiliar with the concepts and terminology involved in environmental studies. The public can draw their own conclusions of the success of the experiments after viewing the three-dimensional images set up in a chronological order. The three-dimensional grids generated during these studies can also be used to create images for visualization and animated sequences that model contamination movement. Animation puts the images of contamination distribution in motion and results in a new perspective on the effects of the remedial demonstration.

DOE is committed to providing technologies to the International Atomic Energy Agency (IAEA) to meet escalating monitoring and inspection requirements associated with the Non-Proliferation Treaty (NPT). One example of technology provided to the IAEA is the information management and remote monitoring capabilities being customized for the IAEA by the International Safeguards Division of the Office of Non-Proliferation and National Security. The ongoing Safeguards Information Management Systems (SIMS) program is an interlaboratory effort providing the IAEA with a range of information management capabilities designed to enhance the effectiveness of their nuclear inspection activities. The initial commitment involved the customization of computer capabilities to provide IAEA with the basic capability to geographically organize, store, and retrieve the large quantity of information involved in their nuclear on site inspection activities in Iraq. This initial system, the International Nuclear Safeguards Inspection Support Tool (INSIST), was developed by DOE`s Pacific Northwest Laboratory (PNL). To date, two INSIST workstations have been deployed at the IAEA. The first has been used to support the IAEA Action Team in the inspection of Iraqi nuclear facilities since August 1993. A second, and similar, workstation has been deployed to support environmental monitoring under the IAEA 93+2 Programme. Both INSIST workstations …

Measurements of disoriented chiral condensates in heavy ion collisions at RHIC and the LHC can yield fundamental information on the nature of the QCD phase transition. I review theoretical efforts to understand the evolution of the condensate and present new results on experimental signals in the single pion spectrum and in pion interferometry.

There are more than 600 facilities at the Savannah River Site (SRS) that are contaminated with either radioactivity, hazardous chemicals, or asbestos. The more significant facilities can be separated into broad categories for decontamination and decommissioning (D&D) planning such as plutonium facilities, waste tanks, chemical separations canyons, and nuclear reactors. Uncertainties exist in the timing, extent of stabilization, and D&D required for these production facilities. Detailed analyses of the risk, costs, and engineering feasibility are needed to define production facility end states to ensure expected reduction in health and environmental risk. In the meantime, scoping projections are required to satisfy Department of Energy (DOE) requirements for 30 year plans, and to indicate where detailed analysis should be funded.