A 10-Hz Terawatt Class Ti:Sapphire Laser System: Development and Applications (open access)

A 10-Hz Terawatt Class Ti:Sapphire Laser System: Development and Applications

We developed a two stage Ti:Sapphire laser system to generate 16 mJ/80fs laser pulses at the pulse repetition rate of 10 Hz. The key deriver for the present design is implementing a highly efficient symmetric confocal pre-amplifier and employing a simple, inexpensive synchronization scheme relying only on a commercial digital delay-generator. We characterized the amplified pulses in spatial-, spectral-, and temporal-domains. The laser system was used to investigate various nonlinear optical processes, and to modify the optical properties of metal- and semiconductor-surfaces. We are currently building a third amplifier to boost the laser power to the multi-terawatt range.
Date: January 12, 2010
Creator: Sharma, A. K.; Smedley, J.; Tsang, T. & Rao, T.
Object Type: Article
System: The UNT Digital Library
500 MW X-BAND RF SYSTEM OF A 0.25 GEV ELECTRON LINAC FOR ADVANCED COMPTON SCATTERING SOURCE APPLICATION (open access)

500 MW X-BAND RF SYSTEM OF A 0.25 GEV ELECTRON LINAC FOR ADVANCED COMPTON SCATTERING SOURCE APPLICATION

A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This high …
Date: May 12, 2010
Creator: Chu, T S; Anderson, S G; Gibson, D J; Hartemann, F V; Marsh, R A; Siders, C et al.
Object Type: Article
System: The UNT Digital Library
2009 Release of the Evaluated Nuclear Data Library (ENDL2009) (open access)

2009 Release of the Evaluated Nuclear Data Library (ENDL2009)

None
Date: August 12, 2010
Creator: Beck, B.; Brown, D. A.; Descalle, M. A.; Hagmann, C.; Hoffman, R.; Ormand, E. et al.
Object Type: Report
System: The UNT Digital Library
Actinic imaging of native and programmed defects on a full-field mask (open access)

Actinic imaging of native and programmed defects on a full-field mask

We describe the imaging and characterization of native defects on a full field extreme ultraviolet (EUV) mask, using several reticle and wafer inspection modes. Mask defect images recorded with the SEMA TECH Berkeley Actinic Inspection Tool (AIT), an EUV-wavelength (13.4 nm) actinic microscope, are compared with mask and printed-wafer images collected with scanning electron microscopy (SEM) and deep ultraviolet (DUV) inspection tools. We observed that defects that appear to be opaque in the SEM can be highly transparent to EUV light, and inversely, defects that are mostly transparent to the SEM can be highly opaque to EUV. The nature and composition of these defects, whether they appear on the top surface, within the multilayer coating, or on the substrate as buried bumps or pits, influences both their significance when printed, and their detectability with the available techniques. Actinic inspection quantitatively predicts the characteristics of printed defect images in ways that may not be possible with non-EUV techniques. As a quantitative example, we investigate the main structural characteristics of a buried pit defect based on EUV through-focus imaging.
Date: March 12, 2010
Creator: Mochi, I.; Goldberg, K. A.; Fontaine, B. La; Tchikoulaeva, A. & Holfeld, C.
Object Type: Article
System: The UNT Digital Library
ADVANCED X-BAND TEST ACCELERATOR FOR HIGH BRIGHTNESS ELECTRON AND GAMMA RAY BEAMS (open access)

ADVANCED X-BAND TEST ACCELERATOR FOR HIGH BRIGHTNESS ELECTRON AND GAMMA RAY BEAMS

In support of Compton scattering gamma-ray source efforts at LLNL, a multi-bunch test stand is being developed to investigate accelerator optimization for future upgrades. This test stand will enable work to explore the science and technology paths required to boost the current 10 Hz monoenergetic gamma-ray (MEGa-Ray) technology to an effective repetition rate exceeding 1 kHz, potentially increasing the average gamma-ray brightness by two orders of magnitude. Multiple bunches must be of exceedingly high quality to produce narrow-bandwidth gamma-rays. Modeling efforts will be presented, along with plans for a multi-bunch test stand at LLNL. The test stand will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. The photoinjector will be a high gradient standing wave structure, featuring a dual feed racetrack coupler. The accelerator will increase the electron energy so that the emittance can be measured using quadrupole scanning techniques. Multi-bunch diagnostics will be developed so that the beam quality can be measured and compared with theory. Design will be presented with modeling simulations, and layout plans.
Date: May 12, 2010
Creator: Marsh, R A; Anderson, S G; Barty, C P; Chu, T S; Ebbers, C A; Gibson, D J et al.
Object Type: Article
System: The UNT Digital Library
Aerosol indirect effects ? general circulation model intercomparison and evaluation with satellite data (open access)

Aerosol indirect effects ? general circulation model intercomparison and evaluation with satellite data

Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs) is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterises aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth ({tau}{sub a}) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. It is found that the model-simulated influence of aerosols on cloud droplet number concentration (N{sub d}) compares relatively well to the satellite data at least over the ocean. The relationship between {tau}{sub a} and liquid water path is simulated much too strongly by the models. This suggests that the implementation of the second aerosol indirect effect mainly in terms of an autoconversion parameterisation has to be revisited in the GCMs. A positive relationship between total cloud fraction (f{sub cld}) and {tau}{sub a} as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the …
Date: March 12, 2010
Creator: Quaas, Johannes; Ming, Yi; Menon, Surabi; Takemura, Toshihiko; Wang, Minghuai; Penner, Joyce E. et al.
Object Type: Article
System: The UNT Digital Library
ALLOYING-DRIVEN PHASE STABILITY IN GROUP VB TRANSITION METALS UNDER COMPRESSION (open access)

ALLOYING-DRIVEN PHASE STABILITY IN GROUP VB TRANSITION METALS UNDER COMPRESSION

None
Date: July 12, 2010
Creator: Landa, A.; Soderlind, P.; Velikokhatnyi, O. I.; Naumov, I. I.; Ruban, A. V.; Peil, O. E. et al.
Object Type: Article
System: The UNT Digital Library
Alphabet Soup - An Overview of Diagnostic Techniques (open access)

Alphabet Soup - An Overview of Diagnostic Techniques

This report gives an overview of diagnostic techniques of "Alphabet Soup".
Date: October 12, 2010
Creator: Smedley, J.
Object Type: Article
System: The UNT Digital Library
Applications of Laser and Synchrotron Based ARPES to Photocathode Research (open access)

Applications of Laser and Synchrotron Based ARPES to Photocathode Research

Laser angle resolved photoelectron spectroscopy (ARPES) provides unique information about angle and energy distribution of photoelectrons. Laser ARPES gives unique insight into how NEA materials work. ARPES combined with some ancillary measurements gives a very complete picture of system electronic physics. For H:C[100] there is now a clear program for engineering as well as development analogous systems. ARPES well suited for identifying 'ideal' photocathodes with intrinsically low emittance and high QE.
Date: October 12, 2010
Creator: Rameau, J.; Smedley. J.; Muller, E.; Kidd, T.; Johnson, P.; Allen, P. et al.
Object Type: Article
System: The UNT Digital Library
Assessing Potential Impacts of Stannous Chloride Based Mercury Treatment on a Receiving Stream Using Real-World Data From Tims Branch, Savannah River Site (open access)

Assessing Potential Impacts of Stannous Chloride Based Mercury Treatment on a Receiving Stream Using Real-World Data From Tims Branch, Savannah River Site

As part of the efforts to develop and implement a comprehensive mercury mitigation strategy for Oak Ridge, the Department of Energy (DOE) is considering deployment of a stannous chloride based treatment technology to decrease the releases of mercury to East Fork Poplar Creek.
Date: July 12, 2010
Creator: Looney, B.; Jackson, D.; Peterson, M.; Mathews, T.; Southworth, G.; Paller, M. et al.
Object Type: Report
System: The UNT Digital Library
Atmospheric Effects on the Performance of Cdznte Single Crystal Detectors (open access)

Atmospheric Effects on the Performance of Cdznte Single Crystal Detectors

The production of high-quality ternary single-crystal materials for radiation detectors has progressed over the past 15 years. One of the more common materials being studied is CdZnTe (CZT), which can be grown using several methods to produce detector-grade materials. The work presented herein examines the effects of environmental conditions including temperature and humidity on detector performance [full-width at half-maximum (FWHM)] using the single pixel with guard detector configuration. The effects of electrical probe placement, reproducibility, and aging are also presented.
Date: May 12, 2010
Creator: Washington, A.; Duff, M. & Teague, L.
Object Type: Article
System: The UNT Digital Library
Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report. October 1 - December 31, 2009. (open access)

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report. October 1 - December 31, 2009.

Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the first quarter of FY 2010 for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x 2,208); for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208); and …
Date: January 12, 2010
Creator: Sisterson, D. L.
Object Type: Report
System: The UNT Digital Library
Batteries: Overview of Battery Cathodes (open access)

Batteries: Overview of Battery Cathodes

The very high theoretical capacity of lithium (3829 mAh/g) provided a compelling rationale from the 1970's onward for development of rechargeable batteries employing the elemental metal as an anode. The realization that some transition metal compounds undergo reductive lithium intercalation reactions reversibly allowed use of these materials as cathodes in these devices, most notably, TiS{sub 2}. Another intercalation compound, LiCoO{sub 2}, was described shortly thereafter but, because it was produced in the discharged state, was not considered to be of interest by battery companies at the time. Due to difficulties with the rechargeability of lithium and related safety concerns, however, alternative anodes were sought. The graphite intercalation compound (GIC) LiC{sub 6} was considered an attractive candidate but the high reactivity with commonly used electrolytic solutions containing organic solvents was recognized as a significant impediment to its use. The development of electrolytes that allowed the formation of a solid electrolyte interface (SEI) on surfaces of the carbon particles was a breakthrough that enabled commercialization of Li-ion batteries. In 1990, Sony announced the first commercial batteries based on a dual Li ion intercalation system. These devices are assembled in the discharged state, so that it is convenient to employ a prelithiated cathode …
Date: July 12, 2010
Creator: Doeff, Marca M
Object Type: Book
System: The UNT Digital Library
Beam commissioning results for the RFQ and MEBT of the EBIS based preinjector for RHIC (open access)

Beam commissioning results for the RFQ and MEBT of the EBIS based preinjector for RHIC

The EBIS based preinjector for both the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory (NSRL) is now being commissioned at Brookhaven National Laboratory (BNL). In 2008, the RFQ for the project was delivered and commissioned using Test EBIS, which was built to demonstrate the high current EBIS's performance. A dedicated beamline after the RFQ was assembled to confirm the RFQ's performance, and the beam energy was measured by a bending dipole magnet. In November 2009, the RFQ was moved to the final location and the vanes were realigned. The beam commissioning with the RHIC-EBIS was started again during March 2010. The RFQ accelerates ions from 17 keV/u to 300 keV/u and operates at 100.625 MHz. It is followed by a short Medium Energy Beam Transport (MEBT), which consists of four quadrupoles and one buncher cavity. Some temporary diagnostics for this commissioning include an emittance probe, TOF system, fast Faraday cup, and beam current measurement units. As of September 2010, the RFQ and the MEBT show expected performance with He{sup +}, Au{sup 32+} and Fe{sup 20+} beams. Further commissioning for higher intensity beams is in progress.
Date: September 12, 2010
Creator: Okamura, M.; Alessi, J.; Beebe, E.; Kondo, K.; Lambiase, R.; Lockey, R. et al.
Object Type: Article
System: The UNT Digital Library
Building America Best Practices Series, Volume 10: Retrofit Techniques and Technologies: Air Sealing (open access)

Building America Best Practices Series, Volume 10: Retrofit Techniques and Technologies: Air Sealing

This report was prepared by PNNL for the U.S. Department of Energy Building America Program. The report provides information to home owners who want to make their existing homes more energy efficient by sealing leaks in the building envelope (ceiling, walls, and floors) that let in drafts and let conditioned air escape. The report provides descriptions of 19 key areas of the home where air sealing can improve home performance and energy efficiency. The report includes suggestions on how to find a qualified weatherization or home performance contractor, what to expect in a home energy audit, opportune times for performing air sealing, and what safety and health concerns to be aware of. The report describes some basic building science concepts and topics related to air sealing including ventilation, diagnostic tools, and code requirements. The report will be available for free download from the DOE Building America website. It is a suitable consumer education tool for home performance and weatherization contractors to share with customers to describe the process and value of home energy retrofits.
Date: April 12, 2010
Creator: Baechler, Michael C.; Gilbride, Theresa L.; Hefty, Marye G.; Cole, Pamala C.; Williamson, Jennifer L. & Love, Pat M.
Object Type: Report
System: The UNT Digital Library
Calibration of a Flat Field Soft X-ray Grating Spectrometer for Laser Produced Plasmas (open access)

Calibration of a Flat Field Soft X-ray Grating Spectrometer for Laser Produced Plasmas

We have calibrated the x ray response of a variable line spaced grating spectrometer, known as the VSG, at the Fusion and Astrophysics Data and Diagnostic Calibration Facility at the Lawrence Livermore National Laboratory (LLNL). The VSG has been developed to diagnose laser produced plasmas, such as those created at the Jupiter Laser Facility and the National Ignition Facility at LLNL, and at both the Omega and Omega EP lasers at University of Rochester's Laboratory for Laser Energetics. The bandwidth of the VSG spans the range from {approx} 6 to 60 {angstrom}. The calibration results present here include the VSG's dispersion and quantum efficiency. The dispersion is determined by measuring the x rays emitted from hydrogen-like and helium-like ions of carbon, nitrogen, oxygen, neon, and aluminum. The quantum efficiency is calibrated to an accuracy of 30% or better by normalizing the x ray intensities recorded by the VSG to those simultaneously recorded by an x ray microcalorimeter spectrometer.
Date: May 12, 2010
Creator: Park, J.; Brown, G. V.; Schneider, M. B.; Baldis, H. A.; Beiersdorfer, P.; Cone, K. V. et al.
Object Type: Article
System: The UNT Digital Library
Carbon contamination topography analysis of EUV masks (open access)

Carbon contamination topography analysis of EUV masks

The impact of carbon contamination on extreme ultraviolet (EUV) masks is significant due to throughput loss and potential effects on imaging performance. Current carbon contamination research primarily focuses on the lifetime of the multilayer surfaces, determined by reflectivity loss and reduced throughput in EUV exposure tools. However, contamination on patterned EUV masks can cause additional effects on absorbing features and the printed images, as well as impacting the efficiency of cleaning process. In this work, several different techniques were used to determine possible contamination topography. Lithographic simulations were also performed and the results compared with the experimental data.
Date: March 12, 2010
Creator: Fan, Y.-J.; Yankulin, L.; Thomas, P.; Mbanaso, C.; Antohe, A.; Garg, R. et al.
Object Type: Article
System: The UNT Digital Library
CARES: Carbonaceous Aerosol and Radiative Effects Study Operations Plan (open access)

CARES: Carbonaceous Aerosol and Radiative Effects Study Operations Plan

The CARES field campaign is motivated by the scientific issues described in the CARES Science Plan. The primary objectives of this field campaign are to investigate the evolution and aging of carbonaceous aerosols and their climate-affecting properties in the urban plume of Sacramento, California, a mid-size, mid-latitude city that is located upwind of a biogenic volatile organic compound (VOC) emission region. Our basic observational strategy is to make comprehensive gas, aerosol, and meteorological measurements upwind, within, and downwind of the urban area with the DOE G-1 aircraft and at strategically located ground sites so as to study the evolution of urban aerosols as they age and mix with biogenic SOA precursors. The NASA B-200 aircraft, equipped with the High Spectral Resolution Lidar (HSRL), digital camera, and the Research Scanning Polarimeter (RSP), will be flown in coordination with the G-1 to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties, and to provide the vertical context for the G-1 and ground in situ measurements.
Date: July 12, 2010
Creator: Zaveri, R. A.; Shaw, W. J. & Cziczo, D. J.
Object Type: Report
System: The UNT Digital Library
Challenges of Algebraic Multigrid across Multicore Architectures (open access)

Challenges of Algebraic Multigrid across Multicore Architectures

Algebraic multigrid (AMG) is a popular solver for large-scale scientific computing and an essential component of many simulation codes. AMG has shown to be extremely efficient on distributed-memory architectures. However, when executed on modern multicore architectures, we face new challenges that can significantly deteriorate AMG's performance. We examine its performance and scalability on three disparate multicore architectures: a cluster with four AMD Opteron Quad-core processors per node (Hera), a Cray XT5 with two AMD Opteron Hex-core processors per node (Jaguar), and an IBM BlueGene/P system with a single Quad-core processor (Intrepid). We discuss our experiences on these platforms and present results using both an MPI-only and a hybrid MPI/OpenMP model. We also discuss a set of techniques that helped to overcome the associated problems, including thread and process pinning and correct memory associations.
Date: April 12, 2010
Creator: Baker, A H; Gamblin, T; Schulz, M & Yang, U M
Object Type: Article
System: The UNT Digital Library
Commissioning of the EBIS-based heavy ion preinjector at Brookhaven (open access)

Commissioning of the EBIS-based heavy ion preinjector at Brookhaven

The status is presented of the commissioning of a new heavy ion preinjector at Brookhaven National Laboratory. This preinjector uses an Electron Beam Ion Source (EBIS), and an RFQ and IH Linac, both operating at 100.625 MHz, to produce 2 MeV/u ions of any species for use, after further acceleration, at the Relativistic Heavy Ion Collider (RHIC) and the NASA Space Radiation Laboratory (NSRL). Among the increased capabilities provided by this preinjector are the ability to produce ions of any species, and the ability to switch between multiple species in 1 second, to simultaneously meet the needs of both science programs. For initial setup, helium beam from EBIS was injected and circulated in the Booster synchrotron. Following this, accelerated Au{sup 32+} and Fe{sup 20+} beams were transported to the Booster injection point, fulfilling DOE requirements for project completion.
Date: September 12, 2010
Creator: Alessi, J.; Beebe, E.; Binello, S.; Hoff, L.; Kondo, K.; Lambiase, R. et al.
Object Type: Article
System: The UNT Digital Library
A Comprehensive Analysis of Uncertainties Affecting the Stellar Mass-Halo Mass Relation for 0<z<4 (open access)

A Comprehensive Analysis of Uncertainties Affecting the Stellar Mass-Halo Mass Relation for 0<z<4

We conduct a comprehensive analysis of the relationship between central galaxies and their host dark matter halos, as characterized by the stellar mass - halo mass (SM-HM) relation, with rigorous consideration of uncertainties. Our analysis focuses on results from the abundance matching technique, which assumes that every dark matter halo or subhalo above a specific mass threshold hosts one galaxy. We provide a robust estimate of the SM-HM relation for 0 &lt; z &lt; 1 and discuss the quantitative effects of uncertainties in observed galaxy stellar mass functions (GSMFs) (including stellar mass estimates and counting uncertainties), halo mass functions (including cosmology and uncertainties from substructure), and the abundance matching technique used to link galaxies to halos (including scatter in this connection). Our analysis results in a robust estimate of the SM-HM relation and its evolution from z=0 to z=4. The shape and evolution are well constrained for z &lt; 1. The largest uncertainties at these redshifts are due to stellar mass estimates (0.25 dex uncertainty in normalization); however, failure to account for scatter in stellar masses at fixed halo mass can lead to errors of similar magnitude in the SM-HM relation for central galaxies in massive halos. We also investigate …
Date: May 12, 2010
Creator: Behroozi, Peter S.; Conroy, Charlie & Wechsler, Risa H.
Object Type: Article
System: The UNT Digital Library
Compressible gas flow through micro-capillary fill-tubes on NIF targets- modeling and experiments (open access)

Compressible gas flow through micro-capillary fill-tubes on NIF targets- modeling and experiments

None
Date: February 12, 2010
Creator: Bhandarkar, S D; Parham, T G & Fair, J E
Object Type: Article
System: The UNT Digital Library
Confirmatory Survey Report for the Section 4 Area at the Rio Algom Ambrosia Lake Facility New Mexico (open access)

Confirmatory Survey Report for the Section 4 Area at the Rio Algom Ambrosia Lake Facility New Mexico

The objectives of the confirmatory survey were to verify that remedial actions were effective in meeting established release criteria and that documentation accurately and adequately described the final radiological conditions of the RAM Ambrosia Lake, Section 4 Areas.
Date: February 12, 2010
Creator: Adams, W. C.
Object Type: Report
System: The UNT Digital Library
Development of a Fiber Laser Welding Capability for the W76, MC4702 Firing Set (open access)

Development of a Fiber Laser Welding Capability for the W76, MC4702 Firing Set

Development work to implement a new welding system for a Firing Set is presented. The new system is significant because it represents the first use of fiber laser welding technology at the KCP. The work used Six-Sigma tools for weld characterization and to define process performance. Determinations of workable weld parameters and comparison to existing equipment were completed. Replication of existing waveforms was done utilizing an Arbitrary Pulse Generator (APG), which was used to modulate the fiber laser’s exclusive continuous wave (CW) output. Fiber laser weld process capability for a Firing Set is demonstrated.
Date: May 12, 2010
Creator: Samayoa, Jose
Object Type: Report
System: The UNT Digital Library