The propagation of laser-generated hot electrons through matter and across narrow vacuum gaps is studied. We use the ATLAS titanium-sapphire laser of Max-Planck-Institut fuer Quantenoptik to irradiate 10 {proportional_to}m to 100 {proportional_to}m thick copper foils at intensities up to 10{sup 19} W/cm{sup 2}, generating electrons with temperatures in the MeV-range. After propagating through the target the electrons are detected via Cerenkov radiation generated in a suitable medium and by hard X-rays emitted from an X-ray ''fluor''. In some experiments a plastic scintillator was used to monitor the electrons. These diagnostics allow to characterize the electrons with respect to their energy, number and directionality. We also investigate the propagation of the hot electrons across narrow vacuum gaps, with a width ranging from several 100 {proportional_to}m down to 25 {proportional_to}m. The effect of self-generated fields in preventing electrons to cross the gap is demonstrated. Implications of these experiments with respect to pumping of X-ray lasers, isochoric heating by X-rays and developing optics for 4th-generation light sources will be discussed.

None

An ultra fast, sub-picosecond resolution streak camera has been recently developed at the LLNL. The camera is a versatile instrument with a wide operating wavelength range. The temporal resolution of up to 300 fs can be achieved, with routine operation at 500 fs. The streak camera has been operated in a wide wavelength range from IR to x-rays up to 2 keV. In this paper we briefly review the main design features that result in the unique properties of the streak camera and present its several scientific applications: (1) Streak camera characterization using a Michelson interferometer in visible range, (2) temporally resolved study of a transient x-ray laser at 14.7 nm, which enabled us to vary the x-ray laser pulse duration from {approx}2-6 ps by changing the pump laser parameters, and (3) an example of a time-resolved spectroscopy experiment with the streak camera.

This is the final report of a three-year project under a Department of Energy Advanced Reciprocating Engine Systems contract. The goal of this project is to develop advanced sensors for real-time combustion monitoring of advanced natural-gas reciprocating engines. Two sensor technologies, ion-mobility spectrometry (IMS) and acoustic gas sensing, were tested for detection of NO{sub x} emissions and monitoring of natural-gas composition. This project examined two novel approaches: use of a corona/spark-discharge ionization source for IMS, and acoustic-relaxation spectra of natural gas for the acoustic gas sensor. We have completed evaluation of laboratory prototypes of both sensors. In this report, we will describe the basic elements of the sensors, their operating and detection principles, their performance, and other issues. Design modifications and suggested applications of field prototypes will also be presented.

Correspondence issued by the General Accounting Office with an abstract that begins "The Senate Special Committee on Aging requested a compilation of GAO's calendar years 2001 and 2002 products pertaining to older Americans and their families."

This report provides a brief background of the blue-slip process, followed by an overview of current issues concerning blue slips, the debate over the need for a blue-slip policy, and recent and possible future changes to the process.

A letter report issued by the General Accounting Office with an abstract that begins "The National Aeronautics and Space Administration (NASA) has struggled to implement a fully integrated financial management system. The lack of such a system has affected the agency's ability to control program costs, raising concerns about the management of its most costly programs, including the space shuttle program and the International Space Station. In April 2000 NASA initiated the Integrated Financial Management Program (IFMP)--its third effort to improve the agencywide management of its resources. Implementation is expected by fiscal year 2006 with an estimated life-cycle cost of nearly $1 billion. This report (1) assesses NASA's methodology for preparing the current life-cycle cost estimate for implementing IFMP, (2) determines whether NASA's current schedule is reasonable, and (3) evaluates NASA's processes for ensuring adequate cost contingencies."

A letter report issued by the General Accounting Office with an abstract that begins "The National Aeronautics and Space Administration (NASA) spends 90 percent--$13 billion--of its budget on contractors. Yet since 1990, GAO has designated NASA's contract management as a high-risk area--in part because the agency failed to implement a financial management system to provide information needed to make key program decisions. In April 2000, NASA initiated its most recent effort to implement an effective financial management system--the Integrated Financial Management Program (IFMP). Three years into the program, GAO found NASA risks building a system that will cost more and do less than planned. As a result, the Congress requested reviews of NASA's IFMP enterprise architecture and financial reporting and program cost and schedule controls."

A letter report issued by the General Accounting Office with an abstract that begins "In April 2000, the National Aeronautics and Space Administration (NASA) began its Integrated Financial Management program (IFMP), its third attempt at modernizing its financial management processes and systems. In April 2003, GAO reported that NASA's acquisition strategy has increased the risk that the agency will implement a system that will cost more and do less than planned. This report is one of a series of reviews of NASA's acquisition and implementation of IFMP, and focuses on the core financial module's ability to provide the information necessary for external financial reporting."

To significantly improve the simulation of climate by general circulation models (GCMs), systematic errors in representations of relevant processes must first be identified, and then reduced. This endeavor demands, in particular, that the GCM parameterizations of unresolved processes should be tested over a wide range of time scales, not just in climate simulations. Thus, a numerical weather prediction (NWP) methodology for evaluating model parameterizations and gaining insights into their behavior may prove useful, provied that suitable adaptations are made for implementation in climate GCMs. This method entails the generation of short-range weather forecasts by realistically initialized climate GCM, and the application of six-hourly NWP analyses and observations of parameterized variables to evaluate these forecasts. The behavior of the parameterizations in such a weather-forecasting framework can provide insights on how these schemes might be improved, and modified parameterizations then can be similarly tested. In order to further this method for evaluating and analyzing parameterizations in climate GCMs, the USDOE is funding a joint venture of its Climate Change Prediction Program (CCPP) and Atmospheric Radiation Measurement (ARM) Program: the CCPP-ARM Parameterization Testbed (CAPT). This article elaborates the scientific rationale for CAPT, discusses technical aspects of its methodology, and presents examples of its …

We present a spatially-explicit individual-based computational model of rodent dynamics, customized for the prairie vole species, M. Ochrogaster. The model is based on trophic relationships and represents important features such as territorial competition, mating behavior, density-dependent predation and dispersal out of the modeled spatial region. Vegetation growth and vole fecundity are dependent on climatic components. The results of simulations show that the model correctly predicts the overall temporal dynamics of the population density. Time-series analysis shows a very good match between the periods corresponding to the peak population density frequencies predicted by the model and the ones reported in the literature. The model is used to study the relation between persistence, landscape area and predation. We introduce the notions of average time to extinction (ATE) and persistence frequency to quantify persistence. While the ATE decreases with decrease of area, it is a bell-shaped function of the predation level: increasing for 'small' and decreasing for 'large' predation levels.

We have measured the production of h{nu} {ge} 4.5 keV x-rays from low-density Ti-doped aerogel targets at the OMEGA laser facility (University of Rochester). The doped-foam density was {approx} 3 mg/cc. Forty beams of the OMEGA laser ({lambda}{sub L} = 0.351 {micro}m) illuminated the two cylindrical faces of the target with a total power that ranged from 7 to 14 TW. The laser interaction fully ionizes the target (n{sub e}/n{sub crit} {ge} 0.1), and allows the laser-bleaching wave to excite, supersonically, the high-Z emitter ions in the sample. Ti K-shell x-ray emission was spectrally resolved with a two-channel crystal spectrometer and also with a set of filtered aluminum x-ray diodes, both instruments provide absolute measurement of the multi-keV x-ray emission. Back-scattered laser energy is observed to be minimal. We find between 40 - 260 J of output with 4.67 {le} h{nu} {le} 5.0 keV.

Impulsive stimulated light scattering and Raman spectroscopy measurements have been made on hcp cobalt to a static pressure of 120 GPa. This is the highest static pressure to date at which acoustic velocities have been directly measured. We find that at pressures above 60 GPa the shear elastic modulus and the Raman frequency of the E{sub 2g} transverse optical phonon exhibit a departure from a linear dependence on density. We relate this behavior to a collapse of the magnetic moment under pressure that has been predicted theoretically, but until now not observed experimentally.

We have performed a numerical modeling study that evaluated the capacity of electrical resistance tomography (ERT) to detect flaws in a passive reactive barrier (PRB). The model barrier is based on a real barrier described in the literature Slater and Binley (2003). It consists of highly conducting, granular iron emplaced within a trench. We assumed that the barrier was filled with a mixture of iron and sand, and that vertical electrode arrays were embedded within the barrier. We have considered (a) characterization and (b) monitoring scenarios. For (a), the objective is to use tomographs of absolute resistivity to detect construction flaws and inhomogeneities in iron distribution shortly after installation. For (b), the objective is to use resistivity change tomographs to detect iron oxidation and barrier plugging as a function of time. The study considered varying PRB hole sizes and locations. For any given model, a hole was located right next to and near the center of an electrode array (maximum sensitivity and resolution expected), at the center between two electrode arrays (moderate sensitivity and resolution), or near the bottom centered between the two arrays (minimum sensitivity and resolution). We also considered various hole sizes. The smallest hole considered had a …

Testimony issued by the General Accounting Office with an abstract that begins "The Department of Energy (Energy) and its predecessor agencies and contractors have employed thousands of workers in the nuclear weapons production complex. Some employees were exposed to toxic substances, including radioactive and hazardous materials, during this work and many subsequently developed illnesses. Subtitle D of the Energy Employees Occupational Illness Compensation Program Act of 2000 allows Energy to help its contractor employees file state workers' compensation claims for illnesses determined by a panel of physicians to be caused by exposure to toxic substances in the course of employment at an Energy facility. Energy began accepting applications under this program in July 2001, but did not begin processing them until its final regulations became effective on September 13, 2002. The Congress mandated that GAO study the effectiveness of the benefit program under Subtitle D of this Act. This testimony is based on GAO's ongoing work on this issue and focuses on three key areas: (1) the number, status, and characteristics of claims filed with Energy; (2) the extent to which there will be a "willing payer" of workers' compensation benefits, that is, an insurer who--by order from, or agreement …

Correspondence issued by the General Accounting Office with an abstract that begins "GAO reviewed the audit reports covering the financial statements of the 82nd Airborne Division Association for fiscal years 2002 and 2001. GAO found no reportable instances of noncompliance. The audit reports included the auditors' opinion that the financial statements of the corporation were presented fairly in accordance with generally accepted accounting principles."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO reviewed the audit reports covering the financial statements of the American National Theater and Academy for fiscal years 2002 and 2001. GAO found no reportable instances of noncompliance. The audit reports included the auditors' opinion that the financial statements of the corporation were presented fairly in accordance with generally accepted accounting principles."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO reviewed the audit reports covering the financial statements of the Aviation Hall of Fame, for fiscal years 2002 and 2001. GAO did not review the auditors' working papers and is not rendering an audit opinion. The audit reports included the auditors' opinion that the financial statements of the corporation were presented fairly in accordance with generally accepted accounting principles."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO reviewed the audit reports covering the financial statements of the Civil Air Patrol, for fiscal year 2001. GAO did not review the auditors' working papers and is not rendering an audit opinion. The audit reports included the auditors' opinion that, with one exception, the financial statements of the corporation were presented fairly in accordance with generally accepted accounting principles. The exception related to the units below wing level not being audited and not being included in these financial statements."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO reviewed the audit reports covering the financial statements of the American Historical Association for fiscal years 2002, 2001, 2000, 1999 and 1998. GAO found no reportable instances of noncompliance. The audit reports included the auditors' opinion that, except for Fiscal Year 1999, the financial statements of the corporation were presented fairly in accordance with generally accepted accounting principles."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO reviewed the audit reports covering the financial statements of the Catholic War Veterans of the United States of America, Inc., for fiscal years 2002, 2001 and 2000. GAO found no reportable instances of noncompliance. The audit reports included the auditors' opinion that the financial statements of the corporation were presented fairly in accordance with generally accepted accounting principles."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO reviewed the audit reports covering the financial statements of the National Academy of Sciences, for the years ended December 31, 1999 through December 31, 2002. GAO found no reportable instances of noncompliance. The audit reports included the auditors' opinion that the financial statements of the corporation were presented fairly in accordance with generally accepted accounting principles."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO reviewed the audit reports covering the financial statements of the National Fund for Medical Education for fiscal years 2002 and 2001. GAO found no reportable instances of noncompliance. The audit reports included the auditors' opinion that the financial statements of the corporation were presented fairly in accordance with generally accepted accounting principles."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO reviewed the audit reports covering the financial statements of the Vietnam Veterans of America Inc., for fiscal years 2003 and 2002. GAO found no reportable instances of noncompliance. The audit reports included the auditors' opinion that the financial statements of the corporation were presented fairly in accordance with generally accepted accounting principles."