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Financial Audit: Bureau of the Public Debt's Fiscal Years 2004 and 2003 Schedules of Federal Debt (open access)

Financial Audit: Bureau of the Public Debt's Fiscal Years 2004 and 2003 Schedules of Federal Debt

A letter report issued by the Government Accountability Office with an abstract that begins "GAO is required to audit the consolidated financial statements of the U.S. government. Due to the significance of the federal debt held by the public to the governmentwide financial statements, GAO has also been auditing the Bureau of the Public Debt's (BPD) Schedules of Federal Debt annually. The audit of these schedules is done to determine whether, in all material respects, (1) the schedules prepared are reliable, (2) BPD management maintained effective internal control relevant to the Schedule of Federal Debt, and (3) BPD complies with selected provisions of significant laws related to the Schedule of Federal Debt. Federal debt managed by BPD consists of Treasury securities held by the public and by certain federal government accounts, referred to as intragovernmental debt holdings. The level of debt held by the public reflects how much of the nation's wealth has been absorbed by the federal government to finance prior federal spending in excess of total federal revenues. Intragovernmental debt holdings represent balances of Treasury securities held by federal government accounts, primarily federal trust funds such as Social Security, that typically have an obligation to invest their excess …
Date: November 5, 2004
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Applying Agreed-Upon Procedures: Airport and Airway Trust Fund Excise Taxes (open access)

Applying Agreed-Upon Procedures: Airport and Airway Trust Fund Excise Taxes

Correspondence issued by the Government Accountability Office with an abstract that begins "We have performed the procedures contained in this report, which we agreed to perform and with which the Inspector General (IG) of the Department of Transportation concurred, solely to assist that office in ascertaining whether the net excise tax revenue distributed to the Airport and Airway Trust Fund (AATF) for the fiscal year ended September 30, 2004, is supported by the underlying records. We evaluated fiscal year 2004 activity affecting distributions to the AATF. The adequacy of the procedures to meet the IG's objectives is the IG's responsibility, and we make no representation in that respect. The procedures we agreed to perform were (1) detailed tests of transactions that represent the underlying basis of amounts distributed to the AATF, (2) review of the Internal Revenue Service's (IRS) quarterly AATF certifications, (3) review of the Department of the Treasury's Financial Management Service adjustments to the AATF for fiscal year 2004, (4) review of IRS's precertification1 of receipts for the second and third quarters of fiscal year 2004, (5) review of certain procedures of the Department of the Treasury's Office of Tax Analysis' (OTA) estimation procedures affecting excise tax distributions …
Date: November 5, 2004
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Border Security: Despite Progress, Weaknesses in Traveler Inspections Exist at Our Nation's Ports of Entry (open access)

Border Security: Despite Progress, Weaknesses in Traveler Inspections Exist at Our Nation's Ports of Entry

A letter report issued by the Government Accountability Office with an abstract that begins "U.S. Customs and Border Protection (CBP) is responsible for keeping terrorists and other dangerous people from entering the country while also facilitating the cross-border movement of millions of travelers. CBP carries out this responsibility at 326 air, sea, and land ports of entry. In response to a congressional request, GAO examined CBP traveler inspection efforts, the progress made and the challenges that remain in staffing and training at ports of entry, and the progress CBP has made in developing strategic plans and performance measures for its traveler inspection program. This is a public version of a For Official Use Only report GAO issued on October 5, 2007. To conduct its work, GAO reviewed and analyzed CBP data and documents related to inspections, staffing, and training, interviewed managers and officers, observed inspections at eight major air and land ports of entry, and tested inspection controls at eight small land ports of entry. Information the Department of Homeland Security (DHS) deemed sensitive has been redacted."
Date: November 5, 2007
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Afghanistan's Security Environment (open access)

Afghanistan's Security Environment

Correspondence issued by the Government Accountability Office with an abstract that begins "In March 2009, out of concern that the overall security situation in Afghanistan had not improved after more than 7 years of U.S. and international efforts, the administration completed a 60-day strategic review of U.S. policy and the security environment in Afghanistan and Pakistan. Based on this review, and recognizing the vital U.S. interest in addressing security threats posed by extremists in Afghanistan and Pakistan, the administration announced a strategic goal of disrupting, dismantling, and eventually defeating these extremists and eliminating their safe havens in both Afghanistan and Pakistan. Subsequently, in August 2009, the United States issued an integrated civilian-military campaign plan for support to Afghanistan. The strategy and campaign plan call for, among other things, the execution of an integrated counterinsurgency mission and continued efforts to build the capacity of military and civilian elements of the Afghan government to lead counterinsurgency and counterterrorism efforts and provide internal security for the Afghan people. Accordingly, the focus for U.S. forces in Afghanistan will be to (1) secure Afghanistan from insurgent and terrorist threats and (2) rapidly train Afghanistan National Security Forces (ANSF) to lead military and law enforcement operations."
Date: November 5, 2009
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Genetically Engineered Crops: Agencies Are Proposing Changes to Improve Oversight, but Could Take Additional Steps to Enhance Coordination and Monitoring (open access)

Genetically Engineered Crops: Agencies Are Proposing Changes to Improve Oversight, but Could Take Additional Steps to Enhance Coordination and Monitoring

A letter report issued by the Government Accountability Office with an abstract that begins "Genetically engineered (GE) crops--including crops engineered to resist pests or tolerate herbicides--are widespread in the United States and around the world. Taking direction from the 1986 Coordinated Framework for Regulation of Biotechnology, the U.S. Department of Agriculture (USDA), Environmental Protection Agency (EPA), and Food and Drug Administration (FDA) regulate GE crops to ensure that they are safe. The unauthorized mixing of some GE crops with non-GE crops has caused controversy and financial harm. GAO examined (1) unauthorized releases of GE crops, (2) coordination among the three agencies, and (3) additional actions they have proposed to improve oversight. GAO gathered data from agencies and stakeholders; used criteria from prior GAO work to assess coordination; and reviewed agency proposals."
Date: November 5, 2008
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Veterans Affairs: Subcommittee Post-Hearing Questions Concerning the Department's Information Technology Management (open access)

Veterans Affairs: Subcommittee Post-Hearing Questions Concerning the Department's Information Technology Management

Correspondence issued by the General Accounting Office with an abstract that begins "The Department of Veterans Affairs' (VA) has made progress in improving its overall management of information technology, including centralization of information technology functions, programs, and funding under the department-level chief information officer (CIO). The department has also made progress in developing an enterprise architecture, improving information security, and managing important information systems initiatives being pursued by the Veterans Benefits Administration (VBA) and the Veterans Health Administration (VHA). GAO reviewed (1) whether VA's proposed business and enabling functions provide the management tools necessary to start the process for implementing VA's enterprise architecture; (2) how veterans have benefited from the VETSNET Program; (3) what must be done to assure successful implementation of the Federal Health Information Exchange (FHIE); and (4) whether VA can realistically implement HealtheVet-Vista by the end of 2005. GAO found that the Federal CIO's Council's guidance on enterprise architecture advises organizations to develop a set of controls to help them successfully manage the process of creating, changing, and using an enterprise architecture. Although the enterprise business functions and key enabling functions are essential components of the architecture that VA is developing, they cannot be considered a primary …
Date: November 5, 2002
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Unmanned Aerial Vehicles: Changes in Global Hawk's Acquisition Strategy Are Needed to Reduce Program Risks (open access)

Unmanned Aerial Vehicles: Changes in Global Hawk's Acquisition Strategy Are Needed to Reduce Program Risks

A letter report issued by the Government Accountability Office with an abstract that begins "Global Hawk offers significant military capabilities to capture and quickly transmit high-quality images of targets and terrain, day or night, and in adverse weather--without risk to an onboard pilot. Global Hawk first flew in the late 1990s as a demonstrator and supported recent combat operations in Afghanistan and Iraq. In 2001, the Air Force began an acquisition program to develop and produce improved Global Hawks. In 2002, the Department of Defense (DOD) restructured and accelerated the program to include a new, larger and more capable air vehicle. GAO was asked to review the program and discuss (1) the restructuring's effect on the Air Force's ability to deliver new capabilities to the warfighter and (2) whether its current business case and management approach is knowledge-based and can help forestall future risks."
Date: November 5, 2004
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Applying Agreed-Upon Procedures: Fiscal Year 2009 Airport and Airway Trust Fund Excise Taxes (open access)

Applying Agreed-Upon Procedures: Fiscal Year 2009 Airport and Airway Trust Fund Excise Taxes

Correspondence issued by the Government Accountability Office with an abstract that begins "We have performed the procedures described in this letter, which we agreed to perform and with which the Inspector General of the Department of Transportation concurred, solely to assist the Inspector General's office in ascertaining whether the net excise tax revenue distributed to the Airport and Airway Trust Fund (AATF) for the fiscal year ended September 30, 2009, is supported by the underlying records. As agreed with the Inspector General's office, we evaluated fiscal year 2009 activity affecting excise tax distributions to the AATF."
Date: November 5, 2009
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Defense Infrastructure: The Army Needs to Establish Priorities, Goals, and Performance Measures for Its Arsenal Support Program Initiative (open access)

Defense Infrastructure: The Army Needs to Establish Priorities, Goals, and Performance Measures for Its Arsenal Support Program Initiative

Correspondence issued by the Government Accountability Office with an abstract that begins "The Army has three government-owned and operated manufacturing arsenals that it considers vital to the Department of Defense's (DOD) industrial base because they provide products or services that are either unavailable from private industry or ensure a ready and controlled source of technical competence and resources in case of national defense contingencies or other emergencies. These three arsenals are Pine Bluff Arsenal, Arkansas; Rock Island Arsenal, Illinois; and Watervliet Arsenal, New York. Pine Bluff's core mission is the production of conventional ammunition and other types of munitions. Rock Island's core mission is weapons manufacturing, and the arsenal is home to the Army's only remaining foundry. Watervliet is the Army's only cannon maker and also produces other armaments and mortars. Historically, the Army's arsenals have generally had vacant or underutilized space. For many years the Army has not provided the capital investment needed to keep pace with modern manufacturing requirements and retain core skills in the arsenal workforce. Additionally, the arsenals have generally had lower workloads during peacetime, but since the onset of the wars in Iraq and Afghanistan they have experienced a surge in workloads to provide vital …
Date: November 5, 2009
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Applying Agreed-Upon Procedures: Highway Trust Fund Excise Taxes (open access)

Applying Agreed-Upon Procedures: Highway Trust Fund Excise Taxes

Correspondence issued by the Government Accountability Office with an abstract that begins "We assisted the Department of Transportation (DOT) in ascertaining whether the net excise tax revenue distributed to the Highway Trust Fund (HTF) for the fiscal year ended September 30, 2004, is supported by the underlying records. As agreed with DOT, we evaluated fiscal year 2004 activity affecting distributions to the HTF. In performing the agreed-upon procedures, we conducted our work in accordance with U.S. generally accepted government auditing standards, which incorporate financial audit and attestation standards established by the American Institute of Certified Public Accountants. These standards also provide guidance for performing and reporting the results of agreed-upon procedures."
Date: November 5, 2004
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Private Pensions: Additional Changes Could Improve Employee Benefit Plan Financial Reporting (open access)

Private Pensions: Additional Changes Could Improve Employee Benefit Plan Financial Reporting

A letter report issued by the Government Accountability Office with an abstract that begins "The Department of Labor (Labor) collects information on fees charged to 401(k) plans primarily through its Form 5500. Labor issued final regulations in November 2007, making changes to, among other things, Schedule C of the Form 5500. Labor put emphasis on reporting the indirect compensation paid to service providers and between service providers, in an effort to capture all of the costs that plan sponsors incur. Congress and others are concerned that Labor's rules could result in duplicative and confusing reporting. Given these concerns, Government Accountability Office (GAO) was asked to examine the new requirements and determine whether Labor's new requirements will provide (1) clear and understandable guidance to plan sponsors and (2) useful information to Labor and others. GAO analyzed Labor's regulations and interviewed Labor and other officials about disclosure and reporting practices."
Date: November 5, 2009
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
U.S. Postal Service: Financial Challenges Continue, with Relatively Limited Results from Recent Revenue-Generation Efforts (open access)

U.S. Postal Service: Financial Challenges Continue, with Relatively Limited Results from Recent Revenue-Generation Efforts

Testimony issued by the Government Accountability Office with an abstract that begins "The U.S. Postal Service's (USPS) financial condition and outlook deteriorated significantly during fiscal year 2009. USPS was not able to cut costs fast enough to offset declining mail volume and revenues resulting from the economic downturn and changing mail use. Facing an unprecedented cash shortfall, USPS stated that it would have insufficient cash on hand to make its mandated $5.4 billion payment to prefund postal retiree health benefits that was due by the end of the fiscal year. In July, 2009, GAO added USPS's financial condition to the list of high-risk areas needing attention by Congress and the executive branch to achieve broad-based transformation. GAO stated that USPS urgently needs to restructure to address its current and long-term financial viability. GAO also stated that USPS needs to use its flexibility to generate revenue through new or enhanced products. This testimony will (1) update USPS's financial condition and outlook, (2) describe changes made by the Postal Accountability and Enhancement Act (PAEA) of 2006 that provided USPS with greater flexibility to generate revenues, (3) outline USPS's revenue-generation actions and results using this flexibility, and (4) discuss options for USPS to …
Date: November 5, 2009
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Applying Agreed-Upon Procedures: Fiscal Year 2009 Highway Trust Fund Excise Taxes (open access)

Applying Agreed-Upon Procedures: Fiscal Year 2009 Highway Trust Fund Excise Taxes

Correspondence issued by the Government Accountability Office with an abstract that begins "The Government Accountability Office (GAO) has performed the procedures to which we agreed upon to perform and with which you concurred, solely to assist your office in ascertaining whether the net excise tax revenue distributed to the Highway Trust Fund (HTF) for the fiscal year ended September 30, 2009, is supported by the underlying records. GAO evaluated fiscal year 2009 activity affecting excise tax distributions to the HTF. GAO conducted the engagement in accordance with U.S. generally accepted government auditing standards, which incorporate certain financial audit and attestation standards established by the American Institute of Certified Public Accountants (AICPA)."
Date: November 5, 2009
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Applying Agreed-Upon Procedures: Federal Unemployment Taxes (open access)

Applying Agreed-Upon Procedures: Federal Unemployment Taxes

Correspondence issued by the Government Accountability Office with an abstract that begins "We assisted the Department of Labor in ascertaining whether the net federal unemployment tax (FUTA) revenue distributed to the Unemployment Trust Fund (UTF) for the fiscal year ended September 30, 2004, is supported by the underlying records. We evaluated fiscal year 2004 activity affecting distributions to the UTF. In performing the agreed-upon procedures, we conducted our work in accordance with U.S. generally accepted government auditing standards, which incorporate financial audit and attestation standards established by the American Institute of Certified Public Accountants. These standards also provide guidance for performing and reporting the results of agreed-upon procedures. The procedures we agreed to perform include (1) detailed tests of transactions that represent the underlying basis of amounts distributed to the UTF and (2) review of key reconciliations of the Internal Revenue Service records to the Department of the Treasury records."
Date: November 5, 2004
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Single-Family Housing: HUD's Risk-Based Oversight of Appraisers Could Be Enhanced (open access)

Single-Family Housing: HUD's Risk-Based Oversight of Appraisers Could Be Enhanced

A letter report issued by the Government Accountability Office with an abstract that begins "Incomplete or inaccurate appraisals resulting in property overvaluations may expose the Department of Housing and Urban Development's (HUD) Single-Family Mortgage Insurance programs--which insured about 3.7million single-family mortgage loans with a total value of about $425 billion in fiscal years 2001 through 2003--to greater financial risks. In 1999, GAO reported on the need for improvements in HUD's oversight of appraisers, which has historically been a challenge for the department. Also, in the past, GAO reported that, due in part to poor oversight of appraisers, HUD's Single-Family Mortgage Insurance programs remained a high-risk area. GAO conducted this review as a follow up to the 1999 report. This report examines (1) how HUD ensures that appraisers it approves are qualified to perform FHA appraisals, (2) the extent to which HUD employs a risk-based monitoring approach, and (3) HUD's efforts to take enforcement action against noncompliant appraisers."
Date: November 5, 2004
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
U.S. Postal Service: Bold Action Needed to Continue Progress on Postal Transformation (open access)

U.S. Postal Service: Bold Action Needed to Continue Progress on Postal Transformation

Testimony issued by the General Accounting Office with an abstract that begins "Last year the President established a commission to examine the future of the U.S. Postal Service (the Service). Its report, issued in July 2003, contained a proposed vision for the Service and recommendations to ensure the viability of postal services. GAO was asked to discuss (1) its perspective on the commission's report and (2) suggestions for next steps. This testimony is based on GAO's analysis of the Commission's report and prior GAO reports and testimonies."
Date: November 5, 2003
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
National Archives: Progress and Risks in Implementing its Electronic Records Archive Initiative (open access)

National Archives: Progress and Risks in Implementing its Electronic Records Archive Initiative

Testimony issued by the Government Accountability Office with an abstract that begins "Since 2001, the National Archives and Records Administration (NARA) has been working to develop a modern Electronic Records Archive (ERA) system, a major information system that is intended to preserve and provide access to massive volumes of all types and formats of electronic records. The system is being developed incrementally over several years, with the first two pieces providing an initial set of functions and additional capabilities to be added in future increments. NARA plans to deploy full system functionality by 2012 at an estimated life-cycle cost of about $550 million. NARA originally planned to complete the first segment of ERA in September 2007. However, software and contracting problems led the agency and its contractor Lockheed Martin to revise the development approach. The revised plan called for parallel development of two different increments: a "base" ERA system with limited functionality and an Executive Office of the President (EOP) system to support the ingestion and search of records from the outgoing Bush Administration. GAO was asked to summarize NARA's progress in developing the ERA system and the ongoing risks the agency faces in completing it. In preparing this testimony, …
Date: November 5, 2009
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Aviation Security: Efforts to Measure Effectiveness and Address Challenges (open access)

Aviation Security: Efforts to Measure Effectiveness and Address Challenges

Testimony issued by the General Accounting Office with an abstract that begins "It has been 2 years since the attacks of September 11,2001, exposed vulnerabilities in the nation's aviation system. Since then, billions of dollars have been spent on a wide range of initiatives designed to enhance the security of commercial aviation. However, vulnerabilities in aviation security continue to exist. As a result, questions have been raised regarding the effectiveness of established initiatives in protecting commercial aircraft from threat objects, and whether additional measures are needed to further enhance security. Accordingly, GAO was asked to describe the Transportation Security Administration's (TSA) efforts to (1) measure the effectiveness of its aviation security initiatives, particularly its passenger screening program; (2) implement a risk management approach to prioritize efforts and focus resources; and (3) address key challenges to further enhance aviation security."
Date: November 5, 2003
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
District of Columbia Issues: D.C. Workforce Reductions and Related Funding Issues (open access)

District of Columbia Issues: D.C. Workforce Reductions and Related Funding Issues

Correspondence issued by the General Accounting Office with an abstract that begins "This report reviews whether the DC government had the authority to use $18 million from the Financial Responsibility and Management Assistance Authority for severance payments during fiscal year 2000. GAO concludes that the District lacked the authority to use the $18 million in Section 157 funding for the fiscal year 2000 workforce reduction. District officials told GAO that they believed that they had the Financial Authority's approval to use 157 funding and, consequently, spent $14.3 million during fiscal year 2000 on workforce reduction activities. However, the District could not document that the Financial Authority had certified compliance with the requirements of Section 157 to authorize the use of the funds. The Financial Authority maintains that it did not approve the use of the funds by the District and had denied in writing the District's request for reimbursement for severance payments. The District accounted for the workforce reduction costs during fiscal year 2000 as if it had access to the Section 157 funding. The District concluded that, had the Section 157 funding been unavailable, one agency would have ended fiscal year 2000 with an operating deficit and two agencies …
Date: November 5, 2001
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Single-cycle nonlinear optics (open access)

Single-cycle nonlinear optics

Nonlinear optics plays a central role in the advancement of optical science and laser-based technologies. We report on the confinement of the nonlinear interaction of light with matter to a single wave cycle and demonstrate its utility for time-resolved and strong-field science. The electric field of 3.3-femtosecond, 0.72-micron laser pulses with a controlled and measured waveform ionizes atoms near the crests of the central wave cycle, with ionization being virtually switched off outside this interval. Isolated sub-100-attosecond pulses of extreme ultraviolet light (photon energy {approx} 80 electron volts), containing {approx} 0.5 nanojoule of energy, emerge from the interaction with a conversion efficiency of {approx} 10{sup -6}. These tools enable the study of the precision control of electron motion with light fields and electron-electron interactions with a resolution approaching the atomic unit of time ({approx} 24 attoseconds).
Date: November 5, 2008
Creator: Max-Planck-Institut fur Quantenoptik
Object Type: Article
System: The UNT Digital Library
The Emma Commissioning Procedure (open access)

The Emma Commissioning Procedure

The author begins with a brief review of the goals of the EMMA experiment. He then describe two stages of EMMA commissioning. The first stage is simply to get the beam to circulate a full turn in the ring, and is done only once during the course of the experiment. The second stage will be repeated several times, at least once for each lattice configuration, and involves two parts: setting the required values for the machine parameters, and determining the tunes and time of flight as a function of energy.
Date: November 5, 2007
Creator: Berg, J. S.
Object Type: Article
System: The UNT Digital Library
A HAMILTONIAN FORMULATION FOR SPIRAL-SECTOR ACCELERATORS. (open access)

A HAMILTONIAN FORMULATION FOR SPIRAL-SECTOR ACCELERATORS.

I develop a formulation for Hamiltonian dynamics in an accelerator with magnets whose edges follow a spiral. I demonstrate using this Hamiltonian that a spiral FFAG can be made perfectly 'scaling'. I examine the effect of tilting an RF cavity with respect a radial line from the center of the machine, potentially with a different angle than the spiral of the magnets.
Date: November 5, 2007
Creator: Berg, J. S.
Object Type: Article
System: The UNT Digital Library
Energetics of Multiple-Ion Species Hohlraum Plasmas (open access)

Energetics of Multiple-Ion Species Hohlraum Plasmas

A study of the laser-plasma interaction processes in multiple-ion species plasmas has been performed in plasmas that are created to emulate the plasma conditions in indirect drive inertial confinement fusion targets. Gas-filled hohlraums with densities of xe22/cc are heated to Te=3keV and backscattered laser light is measured by a suite of absolutely calibrated backscatter diagnostics. Ion Landau damping is increased by adding hydrogen to the CO2/CF4 gas fill. We find that the backscatter from stimulated Brillouin scattering is reduced is monotonically reduced with increasing damping, demonstrating that Landau damping is the controlling damping mechanism in ICF relevant high-electron temperature plasmas. The reduction in backscatter is accompanied by a comparable increase in both transmission of a probe beam and an increased hohlraum radiation temperature, showing that multiple-ion species plasmas improve the overall hohlraum energetics/performance. Comparison of the experimental data to linear gain calculations as well as detailed full-scale 3D laser-plasma interaction simulations show quantitative agreement. Our findings confirm the importance of Landau damping in controlling backscatter from high-electron temperature hohlraum plasmas and have lead to the inclusion of multi-ion species plasmas in the hohlraum point design for upcoming ignition campaigns at the National Ignition Facility.
Date: November 5, 2007
Creator: Neumayer, P; Berger, R; Callahan, D; Divol, L; Froula, D; London, R et al.
Object Type: Article
System: The UNT Digital Library
Fundamental Investigations of Nanoscale Phenomena in Beam-Assisted Nucleation, Growth and Surface Smoothing, Using in situ LEEM (open access)

Fundamental Investigations of Nanoscale Phenomena in Beam-Assisted Nucleation, Growth and Surface Smoothing, Using in situ LEEM

The purposes for which this grant was provided were specifically (1) to construct a tandem instrument that combined a low energy electron microscope (LEEM) with an ion beam source capably of irradiating a sample during observation of the surface using LEEM; and (2) to employ the new machine to whatever degree possible to observe the evolution of clean crystal surfaces during ion beam irradiation. A principal motivation was to investigate the fundamental behavior of radiation damage under circumstances for which the damage can be observed directly in real time as it occurs. A second main motivation was to create tunable perturbations of the defect (adatom and advacancy) equilibrium on clean crystal planes and in this way explore the fundamental kinetics of surface behavior that enters into numerous phenomena of interest to DOE including surface erosion, catalysis, and the damage to crystals caused by impacts of energetic particles. The funding has been employed to successfully pursue all the original goals, and additional opportunities that developed as a result of discoveries made in this research.
Date: November 5, 2008
Creator: Flynn, Colin P.
Object Type: Text
System: The UNT Digital Library