2007 Oak Ridge National Laboratory Annual Illness and Injury Surveillance Report (open access)

2007 Oak Ridge National Laboratory Annual Illness and Injury Surveillance Report

The U.S. Department of Energy’s (DOE) commitment to assuring the health and safety of its workers includes the conduct of epidemiologic surveillance activities that provide an early warning system for health problems among workers. The Illness and Injury Surveillance Program monitors illnesses and health conditions that result in an absence of workdays, occupational injuries and illnesses, and disabilities and deaths among current workers.
Date: March 4, 2009
Creator: United States. Department of Energy. Office of Health, Safety, and Security.
Object Type: Report
System: The UNT Digital Library
High sensitivity resonance frequency measurements of individualmicro-cantilevers using fiber optical interferometry (open access)

High sensitivity resonance frequency measurements of individualmicro-cantilevers using fiber optical interferometry

We describe a setup for the resonance frequency measurement of individual microcantilevers. The setup displays both high spatial selectivity and sensitivity to specimen vibrations by utilizing a tapered uncoated fiber tip. The high sensitivity to specimen vibrations is achieved by the combination of optical Fabry-Perot interferometry and narrow band RF detection. Wave fronts reflected on the specimen and on the fiber tip end face interfere, thus no reference plane on the specimen is needed, as demonstrated with the example of freestanding silicon nitride micro-cantilevers. The resulting system is integrated in a DB-235 dual beam FIB system, thereby allowing the measurement of micro-cantilever responses during observation in SEM mode. The FIB was used to modify the optical fiber tip. At this point of our RF system development, the microcantilevers used to characterize the detector were not modified in situ.
Date: March 4, 2009
Creator: Duden, Thomas & Radmilovic, Velimir
Object Type: Article
System: The UNT Digital Library
ILC Marx Modulator Development Program Status (open access)

ILC Marx Modulator Development Program Status

Development of a first generation prototype (P1) Marx-topology klystron modulator for the International Linear Collider is nearing completion at the Stanford Linear Accelerator Center. It is envisioned as a smaller, lower cost, and higher reliability alternative to the present, bouncer-topology, 'Baseline Conceptual Design'. The Marx presents several advantages over conventional klystron modulator designs. It is physically smaller; there is no pulse transformer (quite massive at ILC parameters) and the energy storage capacitor bank is quite small, owing to the active droop compensation. It is oil-free; voltage hold-off is achieved using air insulation. It is air cooled; the secondary air-water heat exchanger is physically isolated from the electronic components. The P1-Marx employs all solid state elements; IGBTs and diodes, to control the charge, discharge and isolation of the cells. A general overview of the modulator design and the program status are presented.
Date: March 4, 2009
Creator: Burkhart, C.; Beukers, T.; Larsen, R.; Macken, K.; Nguyen, M.; Olsen, J. et al.
Object Type: Article
System: The UNT Digital Library

Fuel Cells on Bio-Gas

The conclusions of this presentation are: (1) Fuel cells operating on bio-gas offer a pathway to renewable electricity generation; (2) With federal incentives of $3,500/kW or 30% of the project costs, reasonable payback periods of less than five years can be achieved; (3) Tri-generation of electricity, heat, and hydrogen offers an alternative route to solving the H{sub 2} infrastructure problem facing fuel cell vehicle deployment; and (4) DOE will be promoting bio-gas fuel cells in the future under its Market Transformation Programs.
Date: March 4, 2009
Creator: Remick, R. J.
Object Type: Presentation
System: The UNT Digital Library
Generation of attosecond x-ray pulses with a multi-cycle two-color ESASE scheme (open access)

Generation of attosecond x-ray pulses with a multi-cycle two-color ESASE scheme

Generation of attosecond x-ray pulses is attracting much attention within the x-ray free-electron laser (FEL) user community. Several schemes using extremely short laser pulses to manipulate the electron bunches have been proposed. In this paper, we extend the attosecond two-color ESASE scheme proposed by Zholents et al. to the long optical cycle regime using a second detuned laser and a tapered undulator. Both lasers can be about ten-optical-cycles long, with the second laser frequency detuned from the first to optimize the contrast between the central and side current spikes. A tapered undulator mitigates the degradation effect of the longitudinal space charge (LSC) force in the undulator and suppresses the FEL gain of all side current peaks. Simulations using the LCLS parameters show a single attosecond x-ray spike of {approx} 110 attoseconds can be produced. The second laser can also be detuned to coherently control the number of the side x-ray spikes and the length of the radiation pulse.
Date: March 4, 2009
Creator: Ding, Y.; Huang, Z.; Ratner, D.; Bucksbaum, P. & Merdji, H.
Object Type: Article
System: The UNT Digital Library
Omega3P: A Parallel Finite-Element Eigenmode Analysis Code for Accelerator Cavities (open access)

Omega3P: A Parallel Finite-Element Eigenmode Analysis Code for Accelerator Cavities

Omega3P is a parallel eigenmode calculation code for accelerator cavities in frequency domain analysis using finite-element methods. In this report, we will present detailed finite-element formulations and resulting eigenvalue problems for lossless cavities, cavities with lossy materials, cavities with imperfectly conducting surfaces, and cavities with waveguide coupling. We will discuss the parallel algorithms for solving those eigenvalue problems and demonstrate modeling of accelerator cavities through different examples.
Date: March 4, 2009
Creator: Lee, Lie-Quan; Li, Zenghai; Ng, Cho & Ko, Kwok
Object Type: Report
System: The UNT Digital Library
Financial Analysis of Incentive Mechanisms to Promote Energy Efficiency: Case Study of a Prototypical Southwest Utility (open access)

Financial Analysis of Incentive Mechanisms to Promote Energy Efficiency: Case Study of a Prototypical Southwest Utility

Many state regulatory commissions and policymakers want utilities to aggressively pursue energy efficiency as a strategy to mitigate demand and energy growth, diversify the resource mix, and provide an alternative to building new, costly generation. However, as the National Action Plan for Energy Efficiency (NAPEE 2007) points out, many utilities continue to shy away from aggressively expanding their energy efficiency efforts when their shareholder's fundamental financial interests are placed at risk by doing so. Thus, there is increased interest in developing effective ratemaking and policy approaches that address utility disincentives to pursue energy efficiency or lack of incentives for more aggressive energy efficiency efforts. New regulatory initiatives to promote increased utility energy efficiency efforts also affect the interests of consumers. Ratepayers and their advocates are concerned with issues of fairness, impacts on rates, and total consumer costs. From the perspective of energy efficiency advocates, the quid pro quo for utility shareholder incentives is the obligation to acquire all, or nearly all, achievable cost-effective energy efficiency. A key issue for state regulators and policymakers is how to maximize the cost-effective energy efficiency savings attained while achieving an equitable sharing of benefits, costs and risks among the various stakeholders. In this study, …
Date: March 4, 2009
Creator: Cappers, Peter; Goldman, Charles; Chait, Michele; Edgar, George; Schlegel, Jeff & Shirley, Wayne
Object Type: Report
System: The UNT Digital Library
International X-Band Linear Collider Accelerator Structure R&D (open access)

International X-Band Linear Collider Accelerator Structure R&D

For more than fifteen years before the International Technology Recommendation Panel (ITRP) decision in August, 2004, there were intensive R&D activities and broad international collaboration among the groups at SLAC, KEK, FNAL, LLNL and other labs for the room temperature X-Band accelerator structures. The goal was to provide an optimized design of the main linac structure for the NLC (Next Linear Collider) or GLC (Global Linear Collider). There have been two major challenges in developing X-band accelerator structures for the linear colliders. The first is to demonstrate stable, long-term operation at the high gradient (65 MV/m) that is required to optimize the machine cost. The second is to strongly suppress the beam induced long-range wakefields, which is required to achieve high luminosity. More than thirty X-band accelerator structures with various RF parameters, cavity shapes and coupler types have been fabricated and tested since 1989. A summary of the main achievements and experiences are presented in this talk including the structure design, manufacturing techniques, high power performance, and other structure related issues. Also, the new progress in collaborating with the CLIC, high gradient structures and X-Band structure applications for RF deflectors and others are briefly introduced.
Date: March 4, 2009
Creator: Wang, J. W.
Object Type: Article
System: The UNT Digital Library
Comment regarding"On the Crooks fluctuation theorem and the Jarzynski equality" [J. Chem. Phys. 129, 091101 (2008)]and"Nonequilibrium fluctuation-dissipation theorem of Brownian dynamics" [J. Chem. Phys. 129, 144113 (2008)] (open access)

Comment regarding"On the Crooks fluctuation theorem and the Jarzynski equality" [J. Chem. Phys. 129, 091101 (2008)]and"Nonequilibrium fluctuation-dissipation theorem of Brownian dynamics" [J. Chem. Phys. 129, 144113 (2008)]

The incongruous"unexpected inapplicability of the [Crook's fluctuation theorem]" is due to an inexplicable, inappropriate use of inconsistent expressions. The girding is secure.
Date: March 4, 2009
Creator: Crooks, Gavin E
Object Type: Article
System: The UNT Digital Library
Improving the performance of the actinic inspection tool with an optimized alignment procedure (open access)

Improving the performance of the actinic inspection tool with an optimized alignment procedure

Extreme ultraviolet (EUV) microscopy is an important tool for the investigation of the performance of EUV masks, for detecting the presence and the characteristics of defects, and for evaluating the effectiveness of defect repair techniques. Aerial image measurement bypasses the difficulties inherent to photoresist imaging and enables high data collection speed and flexibility. It provides reliable and quick feedback for the development of masks and lithography system modeling methods. We operate the SEMATECH Berkeley Actinic Inspection Tool (AIT), a EUV microscope installed at the Advanced Light Source at Lawrence Berkeley National Laboratory. The AIT is equipped with several high-magnification Fresnel zoneplate lenses, with various numerical aperture values, that enable it image the reflective mask surface with various resolution and magnification settings. Although the AIT has undergone significant recent improvements in terms of imaging resolution and illumination uniformity, there is still room for improvement. In the AIT, an off-axis zoneplate lens collects the light coming from the sample and an image of the sample is projected onto an EUV-sensitive CCD camera. The simplicity of the optical system is particularly helpful considering that the AIT alignment has to be performed every time that a sample or a zoneplate is replaced. The alignment …
Date: March 4, 2009
Creator: Mochi, I.; Goldberg, K.A.; Naulleau, P. & Huh, Sungmin
Object Type: Article
System: The UNT Digital Library
Nanoparticles Stabilize Thin Polymer Films: A Fundamental Study to Understand the Phenomenon (open access)

Nanoparticles Stabilize Thin Polymer Films: A Fundamental Study to Understand the Phenomenon

A new understanding of thermodynamics at the nanoscale resulted in a recently discovered first order phase transition that nanoparticles in a polymer film will all segregate to the supporting substrate. This is an unusual phase transition that was predicted using a modeling technique developed at Sandia National Laboratories and required the equivalent of many computational years on one computer. This project is a collaboration between Prof. Michael Mackay's group and Dr. Amalie Frischknecht (Sandia National Laboratories) where experimental observation and theoretical rationalization and prediction are brought together. Other discoveries were that this phase transition could be avoided by changing the nanoparticle properties yielding control of the assembly process at the nanoscale. In fact, the nanoparticles could be made to assemble to the supporting substrate, to the air interface or not assemble at all within a thin polymer film of order 100 nm in thickness. However, when the assembly process is present it is so robust that it is possible to make rough liquid films at the nanoscale due to nanoparticles assembling around three-dimensional objects. From this knowledge we are able to design and manufacture new coatings with particular emphasis on polymer-based solar cells. Careful control of the morphology at the …
Date: March 4, 2009
Creator: Mackay, Michael E.
Object Type: Report
System: The UNT Digital Library
Generating Intense Attosecond X-Ray Pulses Using Ultraviolet-Laser-Induced Microbunching in Electron Beams (open access)

Generating Intense Attosecond X-Ray Pulses Using Ultraviolet-Laser-Induced Microbunching in Electron Beams

We propose a scheme that combines the echo-enabled harmonic generation technique with the bunch compression and allows to generate harmonic numbers of a few hundred in a microbunched beam through up-conversion of the frequency of an ultraviolet seed laser. Sending this beam through a short undulator results in an isolated sub-100 attoseconds pulse of x-ray radiation. Using a representative realistic set of parameters, we show that 1 nm x-ray pulse with peak power exceeding 100 MW and duration as short as 34 attoseconds (FWHM) can be generated from a 200 nm ultraviolet seed laser.
Date: March 4, 2009
Creator: Xiang, D.; Huang, Z. & Stupakov, G.
Object Type: Article
System: The UNT Digital Library
The Quantum Efficiency and Thermal Emittance of Metal Photocathodes (open access)

The Quantum Efficiency and Thermal Emittance of Metal Photocathodes

Modern electron beams have demonstrated the brilliance needed to drive free electron lasers at x-ray wavelengths, with the principle improvements occurring since the invention of the photocathode gun. The state-of-the-art normalized emittance electron beams are now becoming limited by the thermal emittance of the cathode. In both DC and RF photocathode guns, details of the cathode emission physics strongly influence the quantum efficiency and the thermal emittance. Therefore improving cathode performance is essential to increasing the brightness of beams. It is especially important to understand the fundamentals of cathode quantum efficiency and thermal emittance. This paper investigates the relationship between the quantum efficiency and the thermal emittance of metal cathodes using the Fermi-Dirac model for the electron distribution. We derive the thermal emittance and its relationship to the quantum efficiency, and compare our results to those of others.
Date: March 4, 2009
Creator: Dowell, David H. & Schmerge, John F.
Object Type: Article
System: The UNT Digital Library
The Use of Haz-Flote to Efficiently Remove Mercury from Contaminated Materials (open access)

The Use of Haz-Flote to Efficiently Remove Mercury from Contaminated Materials

None
Date: March 4, 2009
Creator: Fallgren, Paul & Bland, Alan
Object Type: Report
System: The UNT Digital Library