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Monitoring and Oversight of Federal Funds Awarded to Bridgeport, Connecticut (open access)

Monitoring and Oversight of Federal Funds Awarded to Bridgeport, Connecticut

Correspondence issued by the General Accounting Office with an abstract that begins "In 2001 and 2002, federal prosecutors indicted the Mayor of Bridgeport, Connecticut, and a dozen conspirators on charges of racketeering, extortion, mail fraud, and tax evasion. In March 2003, the mayor was found guilty on 16 counts, and most of the others indicted have pleaded guilty. While the indictment did not refer to any misuse of federal funds, some of the corrupt activities were associated with projects that had received some federal funding in the past. This corruption has raised concerns about the adequacy of monitoring and oversight of the more than $82 million in federal funds Bridgeport has received in recent years. Congress asked us to examine federally funded programs operated by the city of Bridgeport and determine whether and to what extent the respective federal agencies, including program officials and Offices of Inspector General, have heightened program monitoring and oversight in light of the corruption."
Date: November 26, 2003
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Department of Energy: Reimbursement of Contractor Litigation Costs (open access)

Department of Energy: Reimbursement of Contractor Litigation Costs

Correspondence issued by the General Accounting Office with an abstract that begins "The Department of Energy (DOE) contracts with not-for-profit universities and private companies to operate its facilities. As part of the cost of operating these facilities, DOE can reimburse its contractors for the litigation costs associated with cases brought against them. Each year the department spends millions of dollars in such reimbursements. For the most part, litigation expenses involve the costs of outside counsel and resulting judgments and settlements for a variety of types of cases, such as equal employment opportunity, radiation and/or toxic exposure, personal injury, wrongful termination of employment, and whistleblower protections. Rep. Edward J. Markey asked GAO to study the extent to which DOE reimburses its contractors' litigation costs and the process for doing so. GAO obtained information on (1) how much DOE spends to reimburse litigation costs for its contractors, (2) what major criteria DOE uses to reimburse its contractors for litigation costs and how it implements these criteria, (3) what major criteria the Department of Defense and the National Aeronautics and Space Administration use to reimburse their contractors for litigation costs, (4) the extent to which a state university that is a DOE contractor …
Date: November 26, 2003
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Resolving Legislative Differences in Congress: Conference Committees and Amendments Between the Houses (open access)

Resolving Legislative Differences in Congress: Conference Committees and Amendments Between the Houses

This report summarizes the procedures the two houses of Congress use most frequently to resolve their legislative differences. It is based upon an interpretation of the rules and published precedents of the House and Senate, and an analysis of the application of these rules and precedents in recent practice. It bears emphasizing that this report is not exhaustive nor is it in any way an official statement of House or Senate procedures. It may serve as a useful introduction or general guide, but it should not be considered an adequate substitute for a study of House and Senate rules and precedents themselves, or for consultations with the parliamentarians of the House and Senate on the meaning and possible application of the rules and precedents.
Date: November 26, 2008
Creator: Rybicki, Elizabeth
Object Type: Report
System: The UNT Digital Library
Human Capital: Diversity in the Federal SES and Processes for Selecting New Executives (open access)

Human Capital: Diversity in the Federal SES and Processes for Selecting New Executives

A letter report issued by the Government Accountability Office with an abstract that begins "A diverse Senior Executive Service (SES), which generally represents the most experienced segment of the federal workforce, can be an organizational strength by bringing a wider variety of perspectives and approaches to policy development and implementation, strategic planning, problem solving, and decision making. In a January 2003 report (GAO-03-34), GAO provided data on career SES members by race, ethnicity, and gender as of October 2000 and a statistically estimated projection of what the profile of the SES would be in October 2007 if appointment and separation trends did not change. In response to a request for updated information on the diversity in the SES, GAO is providing information from the Office of Personnel Management's (OPM) Central Personnel Data File (1) on the representation of women and minorities in the SES and the SES developmental pool (i.e., GS-15 and GS-14 positions) for the executive branch as of fiscal year 2007 and comparing this representation to fiscal year 2000 levels and to levels GAO projected for October 2007 in its 2003 report; (2) for fiscal years 2000 and 2007, the average age at which women and minorities were …
Date: November 26, 2008
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
State Children's Health Insurance Program: Program Structure, Enrollment and Expenditure Experiences, and Outreach Approaches for States That Cover Adults (open access)

State Children's Health Insurance Program: Program Structure, Enrollment and Expenditure Experiences, and Outreach Approaches for States That Cover Adults

A letter report issued by the Government Accountability Office with an abstract that begins "In 2006 about 4.5 million individuals were enrolled in the State Children's Health Insurance Program (SCHIP). Congress created SCHIP with the goal of significantly reducing the number of low-income uninsured children. Under certain circumstances, states may also cover adults, and in June 2006 about 349,000 adults were enrolled. Each state receives an annual allotment of federal funds, available as a federal match based on the state's expenditures. Generally, states have 3 years to use each fiscal year's allotment, after which unspent federal funds may be redistributed. Congress initially authorized SCHIP for 10 years, from 1998 through 2007, and provided approximately $40 billion for that period. GAO examined (1) how 10 states that cover adults--parents, childless adults, or both--in SCHIP structured their programs; (2) these states' enrollment and expenditure experiences for adults, which GAO considered in the context of those for all other SCHIP populations (children and pregnant women); and (3) the approaches these states adopted to attract all eligible individuals. To accomplish this, GAO reviewed 10 states that covered adults in SCHIP as of 2007. GAO interviewed officials in the 10 states; reviewed states' 2006 annual …
Date: November 26, 2007
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Combating Terrorism: Funding Data Reported to Congress Should Be Improved (open access)

Combating Terrorism: Funding Data Reported to Congress Should Be Improved

A briefing report issued by the General Accounting Office with an abstract that begins "Congress responded to the attacks of September 11, 2001, with dramatic funding increases to combat terrorism. Even before these attacks, Congress was concerned about increased funding in this area, and based on findings from a 1997 GAO report, mandated that the Office of Management and Budget (OMB) report annually on funding to combat terrorism. In this review, GAO was asked to analyze such funding trends, describe difficulties in coordinating combating terrorism budgets, assess data reported to Congress, and describe the executive branch's efforts to maximize the effective use of combating terrorism funds. The review relied on OMB's definition of "combating terrorism" to include both homeland security and overseas combating terrorism missions."
Date: November 26, 2002
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Natural Disasters: Public Policy Options for Changing the Federal Role in Natural Catastrophe Insurance (open access)

Natural Disasters: Public Policy Options for Changing the Federal Role in Natural Catastrophe Insurance

A letter report issued by the Government Accountability Office with an abstract that begins "In recent years, much attention has been focused on the roles that the private sector and federal government play in providing insurance and financial aid before and after catastrophic events. In this context, GAO examined (1) the rationale for and resources of federal and state programs that provide natural catastrophe insurance; (2) the extent to which Americans living in catastrophe-prone areas of the United States are uninsured and underinsured, and the types and amounts of federal payments to such individuals since the 2005 hurricanes; and (3) public policy options for revising the federal role in natural catastrophe insurance markets. To address these questions, GAO analyzed state and federal programs, examined studies of uninsured and underinsured homeowners and federal payments to them, identified and analyzed policy options, and interviewed officials from private and public sectors in both high- and low-risk areas of the United States. GAO also developed a four-goal framework to help analyze the available options."
Date: November 26, 2007
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Wildlife Services Program: Information on Activities to Manage Wildlife Damage (open access)

Wildlife Services Program: Information on Activities to Manage Wildlife Damage

A letter report issued by the General Accounting Office with an abstract that begins "Birdwatching, hunting, and wildlife photography provide important recreational, aesthetic, and income-generating benefits to the American public. In addition, wildlife help maintain ecosystems, and the mere knowledge that wildlife exist is viewed as beneficial by many people. At the same time, however, some wildlife destroy crops, kill livestock, damage property, and pose risks to public health and safety. Further, as the U.S. population has grown and impinged upon wildlife habitats, conflicts between wildlife and humans and their property have become increasingly common. Wildlife Services, a program within the U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service, is tasked with controlling damage by wildlife. Mammals and birds damage crops, forestry seedlings, and aquaculture products each year, at a cost of hundreds of millions of dollars. In fiscal year 2000, predators killed half a million livestock--mostly lambs and calves--valued at $70 million. To reduce such threats, Wildlife Services conducts operational and research activities with federal, state, and local agencies; agricultural producers and ranchers; private homeowners; and others. In carrying out these activities, Wildlife Services applies the most appropriate methods, whether lethal or nonlethal, of prevention and …
Date: November 26, 2001
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Recreation Fees: Management Improvements Can Help the Demonstration Program Enhance Visitor Services (open access)

Recreation Fees: Management Improvements Can Help the Demonstration Program Enhance Visitor Services

A letter report issued by the General Accounting Office with an abstract that begins "Congress authorized the Recreational Fee Demonstration Program to help federal land management agencies provide high-quality recreational opportunities to visitors and protect resources. The program focuses on recreational activities at the following four land management agencies: the National Park Service, the Fish and Wildlife Service, the Bureau of Land Management, and the Forest Service. Under the fee demonstration program, participating agencies can collect fees at several sites and use them to (1) enhance visitor services, (2) address a backlog of needs for repair and maintenance, and (3) manage and protect resources. The agencies applied "entrance fees" for basic admission to an area and "user fees" for specific activities such as camping or launching a boat. Under the law, 80 percent of program revenue must be used at the site where it was collected. The rest may be distributed to other sites that may or may not be participating in the demonstration program. Some of the sites GAO surveyed experimented with innovative fee designs and collection methods, such as reducing fees during off-peak seasons and allowing visitors to use credit cards, but room for additional innovation exists, particularly …
Date: November 26, 2001
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Postal Pension Funding Reform: Issues Related to the Postal Service's Proposed Use of Pension Savings (open access)

Postal Pension Funding Reform: Issues Related to the Postal Service's Proposed Use of Pension Savings

A letter report issued by the General Accounting Office with an abstract that begins "In April 2003, Congress enacted the Postal Civil Service Retirement System (CSRS) Funding Reform Act of 2003 (P.L. 108-18), which\ lowered the Postal Service's (Service) annual payment for its CSRS obligation by over $2.5 billion beginning in fiscal year 2003. P.L. 108-18 includes requiring (1) the Service to begin making payments into an escrow account in fiscal year 2006, (2) the Service to issue a report on its proposed use of "savings" resulting from the lower CSRS payments, and (3) GAO to evaluate the Service's report and present its findings to Congress. GAO evaluated whether the Service's proposals were consistent with P.L. 108-18; the impact of the escrow account; and whether the proposals were fair to current and future ratepayers, affordable, and helped achieve transformation goals."
Date: November 26, 2003
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Biomedical Research: HHS Direction Needed to Address Financial Conflicts of Interest (open access)

Biomedical Research: HHS Direction Needed to Address Financial Conflicts of Interest

A letter report issued by the General Accounting Office with an abstract that begins "Financial relationships between individual investigators or their research institutions and private industry have yielded significant results, including treatments for such diseases as AIDS and strokes. However, some collaborations have raised concerns that the focus on financial reward might compromise the integrity of the research and the safety of human research subjects. GAO reviewed five universities with broad policies and procedures on financial conflicts of interest. All five had difficulty providing basic data on individual investigators' financial conflicts of interest in clinical research involving human subjects. The universities acknowledged a need for better coordination of information on investigators' financial relationships, and several universities were developing ways to do so. Policies and procedures at the five universities addressed financial conflicts of interest affecting institutions, including technology transfer activities and financial relationships with small start-up companies that market products developed by the universities. The Department of Health and Human Services has had limited success in promoting the integrity of biomedical research and protecting human subjects. HHS has taken steps to improve its oversight and monitoring and has drafted guidance on financial conflicts of interest, but this guidance does not …
Date: November 26, 2001
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Postal Pension Funding Reform: Review of Military Service Funding Proposals (open access)

Postal Pension Funding Reform: Review of Military Service Funding Proposals

A letter report issued by the General Accounting Office with an abstract that begins "The Postal Civil Service Retirement System Funding Reform Act of 2003 (the Act) required the United States Postal Service, Department of the Treasury, and Office of Personnel Management (OPM) to prepare proposals detailing whether and to what extent the Treasury and Postal Service should fund the benefits attributable to the military service of the Postal Service's current and former Civil Service Retirement System (CSRS) employees. The Act required GAO to evaluate the proposals. Our objective in doing so was to assess the agencies' positions and provide additional information where it may be useful."
Date: November 26, 2003
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Medicaid Regulatory Issues (open access)

Medicaid Regulatory Issues

This report provides a summary of seven proposed and final rules affecting the Medicaid program that were issued by the Bush Administration during 2007 and 2008. Six of the seven rules are currently under a congressional moratorium on further administrative action until April 1, 2009. A description of possible administrative and legislative actions to modify these rules, which could be taken by the next administration or the 111th Congress, is also provided.
Date: November 26, 2008
Creator: Herz, Elicia J. & Burrows, Vanessa K.
Object Type: Report
System: The UNT Digital Library
U.S. Arms Sales: Agreements with and Deliveries to Major Clients, 2000-2007 (open access)

U.S. Arms Sales: Agreements with and Deliveries to Major Clients, 2000-2007

This report provides background data on United States arms sales agreements with and deliveries to its major purchasers during calendar years 2000-2007. In a series of data tables, it lists the total dollar values of U.S. government-to-government arms sales agreements with its top five purchasers in five specific regions of the world for three specific periods: 200-2003, 2004-2007, and 2007 alone, and the total dollar values of U.S. arms deliveries to its top five purchasers in those same regions and time periods. The report also provides data tables listing the total dollar values of U.S. government-to-government arms agreements with and deliveries to its top 10 purchasers worldwide for those same time periods.
Date: November 26, 2008
Creator: Grimmett, Richard F.
Object Type: Report
System: The UNT Digital Library
The Legislative Process on the House Floor: An Introduction (open access)

The Legislative Process on the House Floor: An Introduction

This report is an introductory and selective explanation of the rules, procedures, and practices by which the House of Representatives considers public bills and resolutions on the floor. After discussions of the nature of House rules, the differences between the House and the Committee of the Whole, and limitations on debate, the report describes five different ways in which the House may consider, perhaps debate and amend, and then vote on whether to pass legislation. The report also discusses the House's calendars and its order of business, the special rules reported by the Rules Committee, House consideration of Senate amendments and conference reports, and the rules and constitutional requirements affecting voting and quorum procedures.
Date: November 26, 2008
Creator: Davis, Christopher M.
Object Type: Report
System: The UNT Digital Library
Global Climate Change: Three Policy Perspectives (open access)

Global Climate Change: Three Policy Perspectives

The 1992 U.N. Framework Convention on Climate Change requires that signatories, including the United States, establish policies for constraining future emission levels of greenhouse gases, including carbon dioxide (CO2). The George H. W. Bush, Clinton, and George W. Bush Administrations each drafted action plans in response to requirements of the convention. These plans have raised significant controversy and debate. This report examines three starting points from which a U.S. response to the convention is being framed.
Date: November 26, 2008
Creator: Parker, Larry & Blodgett, John
Object Type: Report
System: The UNT Digital Library
ELECTRICAL SAFETY IMPROVEMENT PROJECT A COMPLEX WIDE TEAMING INITIATIVE (open access)

ELECTRICAL SAFETY IMPROVEMENT PROJECT A COMPLEX WIDE TEAMING INITIATIVE

This paper describes the results of a year-long project, sponsored by the Energy Facility Contractors Group (EFCOG) and designed to improve overall electrical safety performance throughout Department of Energy (DOE)-owned sites and laboratories. As evidenced by focused metrics, the Project was successful primarily due to the joint commitment of contractor and DOE electrical safety experts, as well as significant support from DOE and contractor senior management. The effort was managed by an assigned project manager, using classical project-management principles that included execution of key deliverables and regular status reports to the Project sponsor. At the conclusion of the Project, the DOE not only realized measurable improvement in the safety of their workers, but also had access to valuable resources that will enable them to do the following: evaluate and improve electrical safety programs; analyze and trend electrical safety events; increase electrical safety awareness for both electrical and non-electrical workers; and participate in ongoing processes dedicated to continued improvement.
Date: November 26, 2007
Creator: BJ, GRAY
Object Type: Article
System: The UNT Digital Library
Acclerator R&D for a Linear Collider (open access)

Acclerator R&D for a Linear Collider

The goal of this project was to perform simulations of beam transport in linear colliders, with an emphasis on emittance dilution, spin polarization transport, and development and testing of beam based tuning algorithms. Our simulations are based on an existing object-oriented particle-tracking library, Bmad. To facilitate the efficient development of simulations, an accelerator design and analysis program based on Bmad has been developed called Tao (Tool for Accelerator Optics). The three beam-based alignment algorithms, Dispersion Free Steering, Ballistic Alignment (BA), and the Kubo Method have been implemented in Tao. We have studied the effects of magnet misalignments, BPM resolution, beam jitter, stray fields, BPM and steering magnet failure and the effects of various cavity shape wakefields. A parametric study has been conducted in the presence of the above types of errors for all three alignment algorithms. We find that BPM resolution has only modest impact on the effectiveness of beam based alignment. The DFS correction algorithm was found to be very robust in situations where there were BPM and/or steering magnet failures. The wakefields in the main linac are very weak and cause negligible emittance growth. Spin tracking was extended to study all accelerator components between the damping ring and …
Date: November 26, 2008
Creator: Rubin, D.L.; Dugan, G.; Gibbons, L.; Palmer, M.; Patterson, R.; Sagan, D. et al.
Object Type: Report
System: The UNT Digital Library
REMOTE IN-CELL SAMPLING IMPROVEMENTS PROGRAM AT THESAVANNAH RIVER SITE (SRS) DEFENSE WASTE PROCESSING FACILITY (DWPF) (open access)

REMOTE IN-CELL SAMPLING IMPROVEMENTS PROGRAM AT THESAVANNAH RIVER SITE (SRS) DEFENSE WASTE PROCESSING FACILITY (DWPF)

Remote Systems Engineering (RSE) of the Savannah River National Lab (SRNL) in combination with the Defense Waste Processing Facility(DWPF) Engineering and Operations has evaluated the existing equipment and processes used in the facility sample cells for 'pulling' samples from the radioactive waste stream and performing equipment in-cell repairs/replacements. RSE has designed and tested equipment for improving remote in-cell sampling evolutions and reducing the time required for in-cell maintenance of existing equipment. The equipment within the present process tank sampling system has been in constant use since the facility start-up over 17 years ago. At present, the method for taking samples within the sample cells produces excessive maintenance and downtime due to frequent failures relative to the sampling station equipment and manipulator. Location and orientation of many sampling stations within the sample cells is not conducive to manipulator operation. The overextension of manipulators required to perform many in-cell operations is a major cause of manipulator failures. To improve sampling operations and reduce downtime due to equipment maintenance, a Portable Sampling Station (PSS), wireless in-cell cameras, and new commercially available sampling technology has been designed, developed and/or adapted and tested. The uniqueness of the design(s), the results of the scoping tests, and …
Date: November 26, 2007
Creator: Marzolf, A
Object Type: Article
System: The UNT Digital Library
White Paper for U.S. Army Rapid Equipping Force: Waste Heat Recovery with Thermoelectric and Lithium-Ion Hybrid Power System (open access)

White Paper for U.S. Army Rapid Equipping Force: Waste Heat Recovery with Thermoelectric and Lithium-Ion Hybrid Power System

By harvesting waste heat from engine exhaust and storing it in light-weight high-capacity modules, it is believed that the need for energy transport by convoys can be lowered significantly. By storing this power during operation, substantial electrical power can be provided during long periods of silent operation, while the engines are not operating. It is proposed to investigate the potential of installing efficient thermoelectric generators on the exhaust systems of trucks and other vehicles to generate electrical power from the waste heat contained in the exhaust and to store that power in advanced power packs comprised of polymer-gel lithium ion batteries. Efficient inexpensive methods for production of the thermoelectric generator are also proposed. The technology that exists at LLNL, as well as that which exists at industrial partners, all have high technology readiness level (TRL). Work is needed for integration and deployment.
Date: November 26, 2007
Creator: Farmer, J C
Object Type: Report
System: The UNT Digital Library
TANK 5 SAMPLING (open access)

TANK 5 SAMPLING

Tank 5 at the Savannah River Site has been used to store high level waste and is currently undergoing waste removal processes in preparation for tank closure. Samples were taken from two locations to determine the contents in support of Documented Safety Analysis (DSA) development for chemical cleaning. These samples were obtained through the use of the Drop Core Sampler and the Snowbank Sampler developed by the Engineered Equipment & Systems (EES) group of the Savannah River National Laboratory (SRNL).
Date: November 26, 2007
Creator: Vrettos, N; William Cheng, W & Thomas Nance, T
Object Type: Article
System: The UNT Digital Library
Delocalization and hybridization enhance the magnetocaloric effect in Ni2Mn0.75Cu0.25Ga (open access)

Delocalization and hybridization enhance the magnetocaloric effect in Ni2Mn0.75Cu0.25Ga

In view of the looming energy crisis facing our planet, attention increasingly focuses on materials potentially useful as a basis for energy saving technologies. The discovery of giant magnetocaloric (GMC) compounds - materials that exhibit especially large changes in temperature as the externally applied magnetic field is varied - is one such compound 1. These materials have potential for use in solid state cooling technology as a viable alternative to existing gas based refrigeration technologies that use choro-fluoro - and hydro-fluoro-carbon chemicals known to have a severe detrimental effect on human health and environment 2,3. Examples of GMC compounds include Gd5(SiGe)4 4, MnFeP1-xAsx 5 and Ni-Mn-Ga shape memory alloy based compounds 6-8. Here we explain how the properties of one of these compounds (Ni2MnGa) can be tuned as a function of temperature by adding dopants. By altering the free energy such that the structural and magnetic transitions coincide, a GMC compound that operates at just the right temperature for human requirements can be obtained 9. We show how Cu, substituted for Mn, pulls the magnetic transition downwards in temperature and also, counterintuitively, increases the delocalization of the Mn magnetism. At the same time, this reinforces the Ni-Ga chemical bond, raising …
Date: November 26, 2008
Creator: Roy, Sujoy; Blackburn, E.; Valvidares, S. M.; Fitzsimmons, M. R.; Vogel, Sven C.; Khan, M. et al.
Object Type: Article
System: The UNT Digital Library
Removal of Iodide From Groundwater Using Silver Chloride-White Paper (open access)

Removal of Iodide From Groundwater Using Silver Chloride-White Paper

Releases from the F and H Area Seepage Basins on the Savannah River Site (SRS) have caused groundwater plumes that contain a variety of contaminants. These plumes are releasing contaminants into Fourmile Branch, which is a small tributary of the Savannah River. The metallic contaminant releases to the branch are being controlled by base injection. The base injection targets cationic contaminants and was not intended to reduce the concentration of I-129 in groundwater. SRS and the regulatory agencies believe it is appropriate to investigate remedial alternatives that could reduce the I-129. The Savannah River Site Area Closures Projects (ACP) and the Savannah River National Laboratory (SRNL) are developing an innovative in situ treatment for I-129 using silver chloride (AgCl). The proposed AgCl amendment has a very small particle size and is designed to be injected into the contaminated aquifer to capture I-129. The solubility of AgI is several orders of magnitude lower than the solubility of AgCl. Thus, when I-129 comes in contact with AgCl it forms silver iodide (AgI), which is very stable and essentially insoluble in water. SRNL has been performing bench-scale column tests on the effectiveness of silver chloride to capture iodine in an aqueous solution. These …
Date: November 26, 2008
Creator: Denham, M.; Bach, M. & Millings, M.
Object Type: Report
System: The UNT Digital Library
Diamond Amplified Photocathodes (open access)

Diamond Amplified Photocathodes

High-average-current linear electron accelerators require photoinjectors capable of delivering tens to hundreds of mA average current, with peak currents of hundreds of amps. Standard photocathodes face significant challenges in meeting these requirements, and often have short operational lifetimes in an accelerator environment. We report on recent progress toward development of secondary emission amplifiers for photocathodes, which are intended to increase the achievable average current while protecting the cathode from the accelerator. The amplifier is a thin diamond wafer which converts energetic (few keV) primary electrons into hundreds of electron-hole pairs via secondary electron emission. The electrons drift through the diamond under an external bias and are emitted into vacuum via a hydrogen-terminated surface with negative electron affinity (NEA). Secondary emission gain of over 200 has been achieved. Two methods of patterning diamond, laser ablation and reactive-ion etching (RIE), are being developed to produce the required geometry. A variety of diagnostic techniques, including FTIR, SEM and AFM, have been used to characterize the diamonds.
Date: November 26, 2007
Creator: Smedley, J.; Ben-Zvi, Ilan; Bohon, J.; Chang, X.; Grover, R.; Isakovic, A. et al.
Object Type: Article
System: The UNT Digital Library