Feasibility Study for a Recirculating Linac-Based Facility for Femtosecond Dynamics (open access)

Feasibility Study for a Recirculating Linac-Based Facility for Femtosecond Dynamics

LBNL is pursuing design studies and the scientific program for a facility dedicated to the production of x-ray pulses with ultra-short time duration, for application in dynamical studies of processes in physics, biology, and chemistry. The proposed x-ray facility has the short x-ray pulse length ({approx}60 fs FWHM) necessary to study very fast dynamics, high flux (up to approximately 10E11 photons/sec/0.1 percentBW) to study weakly scattering systems, and tuneability over 1-12 keV photon energy. The hard x-ray photon production section of the machine accommodates seven 2-m long undulators. Design studies for longer wavelength sources, using high-gain harmonic generation, are in progress. The x-ray pulse repetition rate of 10 kHz is matched to studies of dynamical processes (initiated by ultra-short laser pulses) that typically have a long recovery time or are not generally cyclic or reversible and need time to allow relaxation, replacement, or flow of the sample. The technique for producing ultra-short x-ray pulses uses relatively long electron bunches to minimize high-peak-current collective effects, and the ultimate x-ray duration is achieved by a combination of bunch manipulation and optical compression. Synchronization of x-ray pulses to sample excitation signals is expected to be of order 50 - 100 fs. Techniques for …
Date: December 21, 2002
Creator: Corlett, J. N.; Barry, W.; Barletta, W. A.; Byrd, J. M.; DeSantis, S.; Doolittle, L. et al.
Object Type: Report
System: The UNT Digital Library
Radiation-Induced Topological Disorder in Irradiated Network Structures (open access)

Radiation-Induced Topological Disorder in Irradiated Network Structures

This report summarizes results of a research program investigating the fundamental principles underlying the phenomenon of topological disordering in a radiation environment. This phenomenon is known popularly as amorphization, but is more formally described as a process of radiation-induced structural arrangement that leads in crystals to loss of long-range translational and orientational correlations and in glasses to analogous alteration of connectivity topologies. The program focus has been on a set compound ceramic solids with directed bonding exhibiting structures that can be described as networks. Such solids include SiO2, Si3N4, SiC, which are of interest to applications in fusion energy production, nuclear waste storage, and device manufacture involving ion implantation or use in radiation fields. The principal investigative tools comprise a combination of experimental diffraction-based techniques, topological modeling, and molecular-dynamics simulations that have proven a rich source of information in the preceding support period. The results from the present support period fall into three task areas. The first comprises enumeration of the rigidity constraints applying to (1) more complex ceramic structures (such as rutile, corundum, spinel and olivine structures) that exhibit multiply polytopic coordination units or multiple modes of connecting such units, (2) elemental solids (such as graphite, silicon and diamond) …
Date: December 21, 2002
Creator: Hobbs, Linn W.
Object Type: Report
System: The UNT Digital Library
Relationship of adiposity to the population distribution of plasma triglyceride concentrations in vigorously active men and women (open access)

Relationship of adiposity to the population distribution of plasma triglyceride concentrations in vigorously active men and women

Context and Objective: Vigorous exercise, alcohol and weight loss are all known to increase HDL-cholesterol, however, it is not known whether these interventions raise low HDL as effectively as has been demonstrated for normal HDL. Design: Physician-supplied medical data from 7,288 male and 2,359 female runners were divided into five strata according to their self-reported usual running distance, reported alcohol intake, body mass index (BMI) or waist circumference. Within each stratum, the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles for HDL-cholesterol were then determined. Bootstrap resampling of least-squares regression was applied to determine the cross-sectional relationships between these factors and each percentile of the HDL-cholesterol distribution. Results: In both sexes, the rise in HDL-cholesterol per unit of vigorous exercise or alcohol intake was at least twice as great at the 95th percentile as at the 5th percentile of the HDL-distribution. There was also a significant graded increase in the slopes relating exercise (km run) and alcohol intake to HDL between the 5th and the 95th percentile. Men's HDL-cholesterol decreased in association with fatness (BMI and waist circumference) more sharply at the 95th than at the 5th percentile of the HDL-distribution. Conclusions: Although exercise, alcohol and adiposity were all …
Date: December 21, 2002
Creator: Williams, Paul T.
Object Type: Article
System: The UNT Digital Library
Appropriations for FY2003: VA, HUD, and Independent Agencies (open access)

Appropriations for FY2003: VA, HUD, and Independent Agencies

Appropriations are one part of a complex federal budget process that includes budget resolutions, appropriations (regular, supplemental, and continuing) bills, rescissions, and budget reconciliation bills. This Report is a guide to one of the 13 regular appropriations bills that Congress passes each year. It is designed to supplement the information provided by the House and Senate Appropriations Subcommittee on VA, HUD, and Independent Agencies.
Date: November 21, 2002
Creator: Snook, Dennis W. & Bourdon, E. Richard
Object Type: Report
System: The UNT Digital Library
Betatron motion with coupling of horizontal and vertical degrees of freedom (open access)

Betatron motion with coupling of horizontal and vertical degrees of freedom

The Courant-Snyder parameterization of one-dimensional linear betatron motion is generalized to two-dimensional coupled linear motion. To represent the 4 x 4 symplectic transfer matrix the following ten parameters were chosen: four beta-functions, four alpha-functions and two betatron phase advances which have a meaning similar to the Courant-Snyder parameterization. Such a parameterization works equally well for weak and strong coupling and can be useful for analysis of coupled betatron motion in circular accelerators as well as in transfer lines. Similarly, the transfer matrix, the bilinear form describing the phase space ellipsoid and the second order moments are related to the eigen-vectors. Corresponding equations can be useful in interpreting tracking results and experimental data.
Date: November 21, 2002
Creator: Bogacz, S. A. & Lebedev, V. A.
Object Type: Article
System: The UNT Digital Library
China-U.S. Relations (open access)

China-U.S. Relations

This report discusses the background information and most recent development in U.S.-China relations since mid-1996. Since the early 1990s, U.S.-China relations have followed an uneven course, with modest improvements overshadowed by various recurring difficulties and setbacks. Longstanding bilateral difficulties have included U.S. problems with the PRC’s worsening human rights record, growing tensions over the PRC’s southern military build-up opposite Taiwan and Taiwan’s political status, and continued controversy over allegations of Chinese proliferation of weapons to unstable regimes.
Date: November 21, 2002
Creator: Dumbaugh, Kerry
Object Type: Report
System: The UNT Digital Library
The control architecture of the D0 experiment (open access)

The control architecture of the D0 experiment

From a controls viewpoint, contemporary high energy physics collider detectors are comparable in complexity to small to medium size accelerators: however, their controls requirements often differ significantly. D0, one of two collider experiments at Fermilab, has recently started a second, extended running period that will continue for the next five years. EPICS [1], an integrated set of software building blocks for implementing a distributed control system, has been adapted to satisfy the slow controls needs of the D0 detector by (1) extending the support for new device types and an additional field bus, (2) by the addition of a global event reporting system that augments the existing EPICS alarm support, and (3) by the addition of a centralized database with supporting tools for defining the configuration of the control system. This paper discusses the control architecture of the current D0 experiment, how the EPICS system was extended to meet the control requirements of a large, high-energy physics detector, and how a formal control system contributes to the management of detector operations.
Date: November 21, 2002
Creator: al., J. Fredrick Bartlett et
Object Type: Article
System: The UNT Digital Library
Department of Education: Guaranteed Student Loan Program Vulnerabilities (open access)

Department of Education: Guaranteed Student Loan Program Vulnerabilities

Correspondence issued by the General Accounting Office with an abstract that begins "Congress requested that GAO investigate weaknesses in the Department of Education's administration of student loans for postsecondary education under the Federal Family Education Loan (FFEL) Program. As a result of the undercover investigation, GAO exposed vulnerabilities in the administration of the FFEL Program. GAO set up a fictitious school and sought and obtained approval for student loans totaling $55,500 on behalf of three fictitious students purportedly attending the school."
Date: November 21, 2002
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Department of Homeland Security: Options for House and Senate Committee Organization (open access)

Department of Homeland Security: Options for House and Senate Committee Organization

With the passage of H.R. 5710, to create a new Department of Homeland Security, Congress has begun discussions regarding the appropriate congressional structure to conduct oversight and fund the new department. Section 1503 of the legislation states the sense of Congress that each chamber should review its committee structure in light of the reorganization of the executive branch. This report addresses some of the options currently being discussed and provides information on legislation in the 107th Congress that attempts to alter the current committee system.
Date: November 21, 2002
Creator: Schneider, Judy & Rundquist, Paul S.
Object Type: Report
System: The UNT Digital Library
Detailed summary of the working group on environmental control (T6) (open access)

Detailed summary of the working group on environmental control (T6)

For the next generation of large accelerators, the civil engineering of accelerator tunnels and associated underground enclosures will be a major component of the technical challenge of building such machines. Because of the large scale involved, the engineering will be required to be as cost-effective as possible, and issues such as ground motion and artificial sources of vibration in the environment will need to be carefully considered. installation and alignment of the machine components will be tasks of unprecedented scope, and will require unprecedented precision. Examine in detail the most important and most difficult aspects of these challenges, both from the point of view of performance and cost-effectiveness. In particular, identify what the site requirements are for the different machines under discussion (JLC, NLC, TESLA, VLHC, Muon source), and describe how tunneling methods are affected by them. Identify, for the different types of accelerators, the different length scales that are involved in defining the alignment tolerances, and what are the tolerances over that length scale. Specify the R and D efforts needed to define the scope of the most critical challenges, and prioritize the efforts, in terms of the potential to provide maximal performance and/or cost-effectiveness. Establish a technology-limited time …
Date: November 21, 2002
Creator: Bialowons, Wilhelm; Laughton, Chris & Seryi, Andrei
Object Type: Article
System: The UNT Digital Library
Development of a Silicon Based Electron Beam Transmission Window for Use in a KrF Excimer Laser System (open access)

Development of a Silicon Based Electron Beam Transmission Window for Use in a KrF Excimer Laser System

The Princeton Plasma Physics Laboratory (PPPL), in collaboration with the Naval Research Laboratory (NRL), is currently investigating various novel materials (single crystal silicon, <100>, <110> and <111>) for use as electron-beam transmission windows in a KrF excimer laser system. The primary function of the window is to isolate the active medium (excimer gas) from the excitation mechanism (field-emission diodes). Chosen window geometry must accommodate electron energy transfer greater than 80% (750 keV), while maintaining structural integrity during mechanical load (1.3 to 2.0 atm base pressure differential, approximate 0.5 atm cyclic pressure amplitude, 5 Hz repetition rate) and thermal load across the entire hibachi area (approximate 0.9 W {center_dot} cm superscript ''-2''). In addition, the window must be chemically resistant to attack by fluorine free-radicals (hydrofluoric acid, secondary). In accordance with these structural, functional, and operational parameters, a 22.4 mm square silicon prototype window, coated with 500 nm thin-film silicon nitride (Si{sub 3}N{sub 4}), has been fabricated. The window consists of 81 square panes with a thickness of 0.019 mm {+-} 0.001 mm. Stiffened (orthogonal) sections are 0.065 mm in width and 0.500 mm thick (approximate). Appended drawing (Figure 1) depicts the window configuration. Assessment of silicon (and silicon nitride) material …
Date: November 21, 2002
Creator: Gentile, C. A.; Fan, H. M.; Hartfield, J. W.; Hawryluk, R. J.; Hegeler, F.; Heitzenroeder, P. J. et al.
Object Type: Report
System: The UNT Digital Library
THE DYNAMICS OF HYDROGEN ATOM ABSTRACTION FROM POLYATOMIC MOLECULES. (open access)

THE DYNAMICS OF HYDROGEN ATOM ABSTRACTION FROM POLYATOMIC MOLECULES.

The hydrogen atom abstraction reaction is an important fundamental process that is extensively involved in atmospheric and combustion chemistry. The practical significance of this type of reaction with polyatomic hydrocarbons is manifest, which has led to many kinetics studies. The detailed understanding of these reactions requires corresponding dynamics studies. However, in comparison to the A + HX {radical} AH + X reactions, the study of the dynamics of A + HR {yields} AH + R reactions is much more difficult, both experimentally and theoretically (here and in the following, A stands for an atom, X stands for a halogen atom, and R stands for a polyatomic hydrocarbon radical). The complication stems from the structured R, in contrast to the structureless X. First of all, there are many internal degrees of freedom in R that can participate in the reaction. In addition, there are different carbon sites from which an H atom can be abstracted, and the dynamics are correspondingly different; there are also multiple identical carbon sites in HR and in the picture of a local reaction, there exist competitions between neighboring H atoms, and so on. Despite this complexity, there have been continuing efforts to obtain insight into the …
Date: November 21, 2002
Creator: Liu, X. & Suits, A. G.
Object Type: Book
System: The UNT Digital Library
Firms That Incorporate Abroad for Tax Purposes: Corporate "Inversions" and "Expatriation" (open access)

Firms That Incorporate Abroad for Tax Purposes: Corporate "Inversions" and "Expatriation"

This report provides information about the Corporate "Inversions" and "Expatriation" on Firms That Incorporate Abroad for Tax Purposes where increasing number of U.S firms have altered their structure by substituting a foreign parent corporation for a domestic one.
Date: November 21, 2002
Creator: Brumbaugh, David L.
Object Type: Report
System: The UNT Digital Library
Homeland Security: A Topical Comparison of H.R. 5710 with H.R. 5005 (open access)

Homeland Security: A Topical Comparison of H.R. 5710 with H.R. 5005

This is a report on the homeland security, specifically a comparison between two defferent standards for new vehicles.
Date: November 21, 2002
Creator: Gressle, Sharon S.
Object Type: Report
System: The UNT Digital Library
Homeland Security: INS Cannot Locate Many Aliens Because It Lacks Reliable Address Information (open access)

Homeland Security: INS Cannot Locate Many Aliens Because It Lacks Reliable Address Information

A letter report issued by the General Accounting Office with an abstract that begins "Following the terrorist attacks of September 11, 2001, the federal government's need to locate aliens in the United States was considerably heightened. Without reliable alien address information, the government is impeded in its ability to find aliens who represent a national security threat or who could help with the nation's anti-terrorism efforts. Requesters from both the Senate and House asked GAO to review the reliability of INS's alien address information and identify the ways it could be improved."
Date: November 21, 2002
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
An integrated mechanical design concept for the final focusingregion for the HIF point design (open access)

An integrated mechanical design concept for the final focusingregion for the HIF point design

A design study was undertaken to develop a ''first cut'' integrated mechanical design concept of the final focusing region for a conceptual IFE power plant that considers the major issues which must be addressed in an integrated driver and chamber system. The conceptual design in this study requires a total of 120 beamlines located in two conical arrays attached on the sides of the target chamber 180 degrees apart. Each beamline consists of four large-aperture superconducting quadrupole magnets and a dipole magnet. The major interface issues include radiation shielding and thermal insulation of the superconducting magnets; reaction of electromagnetic loads between the quadrupoles; alignment of the magnets; isolation of the vacuum regions in the target chamber from the beamline, and assembly and maintenance.
Date: November 21, 2002
Creator: Brown, T.; Sabbi, G. L.; Barnard, J. J.; Heitzenroeder, P.; Chun, J.; Schmidt, J. et al.
Object Type: Article
System: The UNT Digital Library
Lebanon (open access)

Lebanon

None
Date: November 21, 2002
Creator: Mark, Clyde R.
Object Type: Report
System: The UNT Digital Library
Methods for Verification of the Hydrogen and Boron Content of the RCSB for Storage of HEU at the HEUMF (open access)

Methods for Verification of the Hydrogen and Boron Content of the RCSB for Storage of HEU at the HEUMF

BoroBond{trademark}, which is a ceramic material containing natural boron carbide (B{sub 4}C, a neutron absorber) and water (a neutron attenuator), is the filler material of the Rackable Can Storage Boxes (RCSBs) that will store highly enriched uranium in cans at the Highly Enriched Uranium Materials Facility (HEUMF). Both attenuation and absorption are essential for criticality safety of the fissile material stored in RCSBs. This BoroBond{trademark} material has not yet been used for storage of highly enriched uranium (HEU). To characterize the neutron attenuation and neutron absorption properties of this material, ORNL has performed an extensive series of measurements (over 900) which included: fast neutron and gamma time-of-flight transmission utilizing the Nuclear Materials Identification System (NMIS), thermal and epithermal neutron counting with {sup 3}He proportional counters, and activation analysis with gamma ray spectrometry using a high purity germanium (HPGe) detector. These measurements were performed for a series of 12 x 12-inch square blocks of thickness varying from 2 to 12 inches, with natural B{sub 4}C contents of approximately 0, 2.3, 4.6, and 9 wt%, and varying water contents achieved by baking the blocks to remove approximately 5/6 of the water. These measurements were also performed with a special mockup of the …
Date: November 21, 2002
Creator: Mihalczo, J. T. & Neal, J. S.
Object Type: Report
System: The UNT Digital Library
Military Health Care: The Issue of "Promised" Benefits (open access)

Military Health Care: The Issue of "Promised" Benefits

None
Date: November 21, 2002
Creator: Burrelli, David F.
Object Type: Report
System: The UNT Digital Library
Military Health Care: The Issue of “Promised” Benefits (open access)

Military Health Care: The Issue of “Promised” Benefits

None
Date: November 21, 2002
Creator: Burrelli, David F.
Object Type: Report
System: The UNT Digital Library
Purchases of Degrees from Diploma Mills (open access)

Purchases of Degrees from Diploma Mills

Correspondence issued by the General Accounting Office with an abstract that begins "This report discusses the investigation of diploma mills that illegally sell fraudulent academic degrees to individuals that use them to gain positions and increase income based upon these documents. Per request, GAO handled the undercover operation and successfully purchased a degree from a diploma mill to demonstrate how easily one can be purchased. Individuals found guilty of purchasing such documents were contacted and interviewed as well, further concluding the identity of a diploma mill, Degrees-R-Us. The owner was questioned and admitted to the sales of approximately 100 fraudulent degrees over the past 2 years when his business began. This matter will be investigated by both the Federal Trade Commission and the U.S. Postal Service as well."
Date: November 21, 2002
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Saudi Arabia: Current Issues and U.S. Relations (open access)

Saudi Arabia: Current Issues and U.S. Relations

None
Date: November 21, 2002
Creator: Prados, Alfred B.
Object Type: Report
System: The UNT Digital Library
Scientists use GEANIE to Study Isotopes of Iridium and Europium to Improve Radiochemical Diagnostics in Nuclear Devices (open access)

Scientists use GEANIE to Study Isotopes of Iridium and Europium to Improve Radiochemical Diagnostics in Nuclear Devices

Radiochemical diagnostics play an important role in helping scientists understand the detonation of a nuclear device. Sometimes some elements or isotopes are inserted as radiochemical detectors at various locations in the nuclear device. During the detonation of the device, these detectors are subjected for a short time to the intense flux of neutrons emitted through fission and possibly through fusion of light elements (usually deuterium and tritium). After the detonation, the radiochemical detectors and their long-lived activation products are retrieved from the area where the underground explosion took place. These radiochemical samples are analyzed to extract information about how the device operated. A large amount of such radiochemical data exist from past nuclear-device tests.
Date: November 21, 2002
Creator: Becker, J. A. & Nelson, R.
Object Type: Report
System: The UNT Digital Library
Synchrotron radiation issues in future hadron colliders (open access)

Synchrotron radiation issues in future hadron colliders

Hadron machines mostly use high field superconducting magnets operating at low temperatures. Therefore the issue of extracting a SR power heat load becomes more critical and costly. Conceptual solutions to the problem exist in the form of beam screens and photon stops. Cooled beam screens are more expensive in production and operation than photon stops, but they are, unlike photon stops, routinely used in existing machines. Photon stops are the most economical solution because the heat load is extracted at room temperature. They presently consider it most prudent to work with a combined beam screen and photon stop approach, in which the photon stop absorbs most of the SR power, and the beam screen serves only the vacuum purpose. Provided that the recently launched photon stop R and D [10] supports it, we would like to explore solutions with photon stops only. This would allow to reduce the magnet apertures to a certain extent with respect to those required to accommodate high SR power compliant beam screens and reduce cost. The possibility of magnet designs, which have larger vertical apertures where large cooling capillaries can be housed at no additional cost, would allow to soften this statement somewhat and should …
Date: November 21, 2002
Creator: Bauer, P.; Darve, C. & Terechkine, I.
Object Type: Article
System: The UNT Digital Library