Topics discussed in the conference included the following: Radiation Physics, Radiation Chemistry and modelling--Radiation physics and dosimetry; Electron transfer in biological media; Radiation chemistry; Biophysical and biochemical modelling; Mechanisms of DNA damage; Assays of DNA damage; Energy deposition in micro volumes; Photo-effects; Special techniques and technologies; Oxidative damage. Molecular and cellular effects-- Photobiology; Cell cycle effects; DNA damage: Strand breaks; DNA damage: Bases; DNA damage Non-targeted; DNA damage: other; Chromosome aberrations: clonal; Chromosomal aberrations: non-clonal; Interactions: Heat/Radiation/Drugs; Biochemical effects; Protein expression; Gene induction; Co-operative effects; ``Bystander'' effects; Oxidative stress effects; Recovery from radiation damage. DNA damage and repair -- DNA repair genes; DNA repair deficient diseases; DNA repair enzymology; Epigenetic effects on repair; and Ataxia and ATM.

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.

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A Two-Modulator Generalized Ellipsometer (2-MGE) has been extremely useful in characterizing optical properties of uniaxial bulk materials, thin films and diffraction gratings. The instrument consists of two polarizer-photoelastic modulator pairs, one operating as the polarization state generator and the other as the polarization state detector. Each photoelastic modulator operates at a different remnant frequency (such as 50 kHz and 60 kHz), making it possible to measure eight elements of the reduced sample Mueller matrix simultaneously. In certain configurations, light reflection from non-depolarizing anisotropic samples can be completely characterized by a single measurement, and the entire reduced Jones matrix can be determined, including the cross polarization coefficients. The calibration of the instrument involves the measurement of the azimuthal angle of the polarizer with respect to the modulator, the modulation amplitude, and the modulator strain for each polarizer photoelastic modulator pair, where the last two are functions of wavelengths. In addition, it is essential to calibrate the azimuthal angles of the polarization state generator and the polarization state detector with respect to the plane of incidence in the ellipsometry configuration that is used in the measurements. Because two modulators operating at different frequencies are used, these calibrations are actually easier and more …

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.

To address the current and future needs for nuclear materials management and safeguards information, Lawrence Livermore National Laboratory envisions an integrated nuclear information system that will support several functions. The vision is to link distributed information systems via a common communications infrastructure designed to address the information interdependencies between two major elements: Domestic, with information about specific nuclear materials and their properties, and International, with information pertaining to foreign nuclear materials, facility design and operations. The communication infrastructure will enable data consistency, validation and reconciliation, as well as provide a common access point and user interface for a broad range of nuclear materials information. Information may be transmitted to, from, and within the system by a variety of linkage mechanisms, including the Internet. Strict access control will be employed as well as data encryption and user authentication to provide the necessary information assurance. The system can provide a mechanism not only for data storage and retrieval, but will eventually provide the analytical tools necessary to support the U.S. government's nuclear materials management needs and non-proliferation policy goals.

It is not uncommon for remote sensing systems to produce in excess of 100 Mbytes/sec. Los Alamos National Laboratory designed a reconfigurable computer to tackle the signal and image processing challenges of high bandwidth sensors. Reconfigurable computing, based on field programmable gate arrays, offers ten to one hundred times the performance of traditional microprocessors for certain algorithms. This paper discusses the architecture of the computer and the source of performance gains, as well as an example application. The calculation of multiple matched filters applied to multispectral imagery, showing a performance advantage of forty-five over Pentium II (450 MHz), is presented as an exemplar of algorithms appropriate for this technology.

The measurement sensitivity of CO{sub 2} differential absorption LIDAR (DIAL) can be affected by a number of different processes. Two of these processes are atmospheric optical turbulence and reflective speckle. Atmospheric optical turbulence affects the beam distribution of energy and phase on target. The effects of this phenomenon include beam spreading, beam wander and scintillation which can result in increased shot-to-shot signal noise. In addition, reflective speckle alone has been shown to have a major impact on the sensitivity of CO{sub 2} DIAL. The authors have previously developed a Huygens-Fresnel wave optics propagation code to separately simulate the effects of these two processes. However, in real DIAL systems it is a combination of these phenomena, the interaction of atmospheric optical turbulence and reflective speckle, that influences the results. In this work, the authors briefly review a description of the model including the limitations along with a brief summary of previous simulations of individual effects. The performance of the modified code with respect to experimental measurements affected by atmospheric optical turbulence and reflective speckle is examined. The results of computer simulations are directly compared with lidar measurements and show good agreement. In addition, simulation studies have been performed to demonstrate the …

A high sensitivity, CO{sub 2} lidar detector, based on recent advances in ultra-low noise, readout integrated circuits (ROIC), is being developed. This detector will combine a high speed, low noise focal plane array (FPA) with a dispersive grating spectrometer. The spectrometer will filter the large background flux, thereby reducing the limiting background photon shot noise. In order to achieve the desired low noise levels, the HgCdTe FPA will be cooled to {approximately}50K. High speed, short pulse operation of the lidar system should enable the detector to operate with the order of a few noise electrons in the combined detector/ ROIC output. Current receiver design concepts will be presented, along with their expected noise performance.

Semiweekly newspaper from Levelland, Texas that includes local, state, and national news along with advertising.

The Oak Ridge National Laboratory has been instrumental in developing ultraprecision technologies for the fabrication of optical devices. We are currently extending our ultraprecision capabilities to the design, fabrication, and testing of micro-optics and MEMS devices. Techniques have been developed in our lab for fabricating micro-devices using single point diamond turning and ion milling. The devices we fabricated can be used in micro-scale interferometry, micro-positioners, micro-mirrors, and chemical sensors. In this paper, we focus on the optimization of microstructure performance using finite element analysis and the experimental validation of those results. We also discuss the fabrication of such structures and the optical testing of the devices. The performance is simulated using finite element analysis to optimize geometric and material parameters. The parameters we studied include bimaterial coating thickness effects; device length, width, and thickness effects, as well as changes in the geometry itself. This optimization results in increased sensitivity of these structures to absorbed incoming energy, which is important for photon detection or micro-mirror actuation. We have investigated and tested multiple geometries. The devices were fabricated using focused ion beam milling, and their response was measured using a chopped photon source and laser triangulation techniques. Our results are presented and …

An oral history interview transcript conducted by Rebecca Wright featuring Helen Wyatt Snapp, Marjorie Popell Sizemore, Doris Elkington Hamaker, Mary Ann Baldner Gordon, Mary Anna "Marty" Martin Wyall, and Teresa D. James. Wrights asks about the group's experiences in either Women Airforce Service Pilots program or the Women's Auxiliary Ferrying Squadron and the prejudice of the 1940s.

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The Spallation Neutron Source (SNS) under construction at the Oak Ridge National Laboratory will be the most important new neutron scattering facility in the United States. Neutron scattering instruments for the SNS will require large area detectors with fast response (< 1 microsecond), high efficiency over a wide range of neutron energies (0.1 to 10 eV), and low gamma ray sensitivity. We are currently developing area neutron detectors based on a combination of 6 LiF/ZnS scintillator screens coupled to a wavelength-shifting fiber optic readout array. A 25 x 25-cm prototype detector is currently under development. Initial tests at the High Flux Isotope Reactor have demonstrated good imaging properties coupled with very low gamma ray sensitivity. In addition, we have developed a multi-layer scintillator/fiber detector to replace existing He-3 gas detector tubes for higher speed operation. This detector has demonstrated a neutron detection efficiency of over 75% at a neutron energy of 0.056 eV or about twice thermal. The response time of this detector is approximately 1 microsecond. Details of the design and test results of both detectors will be presented.

An overview of the radiographic capabilities with emphasis on electronic image detection and processing at the Los Alamos National Laboratory is presented. Fixed facilities and portable x-ray sources and imaging systems make up the Los Alamos capability. Examples of imaging with large area amorphous silicon imaging panels, a portable computed tomography system, high speed x-ray imaging applications and equipment, and small area, high resolution imagers are given. Radiographic simulation and reverse engineering from radiographic images to computer aided design files and solid models is also presented.

Semiweekly newspaper from Seminole, Texas that includes local, state, and national news along with advertising.

A common perspective on the numerical solution of the equation Euler equations for shock physics is examined. The common viewpoint is based upon the selection of nonlinear wavespeeds upon which the dissipation (implicit or explicit) is founded. This perspective shows commonality between Riemann solver based method (i.e. Godunov-type) and artificial viscosity (i.e. von Neumann-Richtmyer). As an example we derive an improved nonlinear viscous stabilization of a Richtmyer-Lax-Wendroff method. Additionally, we will define a form of classical artificial viscosity based upon the HLL Riemann solver.

Daily newspaper from Weatherford, Texas that includes local, state, and national news along with advertising.