Calibration of a High Resolution Soft X-ray Spectrometer (open access)

Calibration of a High Resolution Soft X-ray Spectrometer

A high resolution grating spectrometer (HRGS) with 2400 line/mm variable line spacing grating for the 10-50 {angstrom} wavelength range has been designed for laser-produced plasma experiments at the Lawrence Livermore National Laboratory (LLNL). The spectrometer has a large radius of curvature, R=44.3 m, is operated at a 2{sup o} grazing angle and can record high signal-to-noise spectra when used with a low-noise, cooled, charge-coupled device detector. The instrument can be operated with a 10-25 {micro}m wide slit to achieve the best spectral resolving power on laser plasma sources, approaching 2000, or in slitless mode with a small symmetrical emission source. Results will be presented for the spectral response of the spectrometer cross-calibrated at the LLNL Electron Beam Ion Trap facility using the broadband x-ray energy EBIT Calorimeter Spectrometer (ECS).
Date: January 26, 2010
Creator: Dunn, J; Beiersdorfer, P; Brown, G V & Magee, E W
Object Type: Article
System: The UNT Digital Library
Carrier heating in disordered conjugated polymers in electric field (open access)

Carrier heating in disordered conjugated polymers in electric field

The electric field dependence of charge carrier transport and the effect of carrier heating in disordered conjugated polymers were investigated. A parameter-free multiscale methodology consisting of classical molecular dynamics simulation for the generation of the atomic structure, large system electronic structure and electron-phonon coupling constants calculations and the procedure for extracting the bulk polymer mobility, was used. The results suggested that the mobility of a fully disordered poly(3-hexylthiophene) (P3HT) polymer increases with electric field which is consistent with the experimental results on samples of regiorandom P3HT and different from the results on more ordered regioregular P3HT polymers, where the opposite trend is often observed at low electric fields. We calculated the electric field dependence of the effective carrier temperature and showed however that the effective temperature cannot be used to replace the joint effect of temperature and electric field, in contrast to previous theoretical results from phenomenological models. Such a difference was traced to originate from the use of simplified Miller-Abrahams hopping rates in phenomenological models in contrast to our considerations that explicitly take into account the electronic state wave functions and the interaction with all phonon modes.
Date: January 26, 2010
Creator: Vukmirovic, Nenad & Wang, Lin-Wang
Object Type: Article
System: The UNT Digital Library
Laser-induced Ramp Compression of Tantalum and Iron to Over 300 GPa: EOS and X-ray Diffraction (open access)

Laser-induced Ramp Compression of Tantalum and Iron to Over 300 GPa: EOS and X-ray Diffraction

None
Date: January 26, 2010
Creator: Eggert, J. H.; Bastea, M.; Braun, D.; Fujino, D.; Rygg, R.; Smith, R. et al.
Object Type: Article
System: The UNT Digital Library
LLNL Genomic Assessment: Viral and Bacterial Sequencing Needs for TMTI, Task 1.4.2 Report (open access)

LLNL Genomic Assessment: Viral and Bacterial Sequencing Needs for TMTI, Task 1.4.2 Report

Good progress has been made on both bacterial and viral sequencing by the TMTI centers. While access to appropriate samples is a limiting factor to throughput, excellent progress has been made with respect to getting agreements in place with key sources of relevant materials. Sharing of sequenced genomes funded by TMTI has been extremely limited to date. The April 2010 exercise should force a resolution to this, but additional managerial pressures may be needed to ensure that rapid sharing of TMTI-funded sequencing occurs, regardless of collaborator constraints concerning ultimate publication(s). Policies to permit TMTI-internal rapid sharing of sequenced genomes should be written into all TMTI agreements with collaborators now being negotiated. TMTI needs to establish a Web-based system for tracking samples destined for sequencing. This includes metadata on sample origins and contributor, information on sample shipment/receipt, prioritization by TMTI, assignment to one or more sequencing centers (including possible TMTI-sponsored sequencing at a contributor site), and status history of the sample sequencing effort. While this system could be a component of the AFRL system, it is not part of any current development effort. Policy and standardized procedures are needed to ensure appropriate verification of all TMTI samples prior to the investment …
Date: January 26, 2010
Creator: Slezak, T; Borucki, M; Lam, M; Lenhoff, R & Vitalis, E
Object Type: Report
System: The UNT Digital Library
Measurements of the Motion of Plasma Filaments in a Plasma Ball (open access)

Measurements of the Motion of Plasma Filaments in a Plasma Ball

Measurements were made of the motion of the filamentary structures in a plasma ball using high speed cameras and other optical detectors. These filaments traverse the ball radially at ~106 cm/sec at the driving frequency of ~26 kHz, and drift upward through the ball at ~1 cm/sec. Varying the applied high voltage and frequency caused the number, length, and diameter of the filaments to change. A custom plasma ball was constructed to observe the effects of varying gas pressure and species on the filament structures.
Date: January 26, 2010
Creator: M. Campanell, J. Laird, T. Provost, S. Vasquez, S.J. Zweben
Object Type: Report
System: The UNT Digital Library
Mechanical Damage, Ignition, and Burn: Experiment, Model Development, and Computer Simulations to Study High-Explosive Violent Response (HEVR) (open access)

Mechanical Damage, Ignition, and Burn: Experiment, Model Development, and Computer Simulations to Study High-Explosive Violent Response (HEVR)

None
Date: January 26, 2010
Creator: Reaugh, J E & Jones, A G
Object Type: Article
System: The UNT Digital Library
THE ROLE FUNGI AND YEAST IN MONITORED NATURAL ATTENUATION (open access)

THE ROLE FUNGI AND YEAST IN MONITORED NATURAL ATTENUATION

Fungi and yeast have been characterized as important components in the bioremediation of organic contaminants in soil and water including polyaromatic hydrocarbons (PAHs); however, research into their ability to metabolize these compounds in extreme environments has been limited. In this work forty-three fungi and yeasts were isolated from a PAH-contaminated sludge waste lagoon in Poland. The lagoon was part of a monitored natural attenuation (MNA) study where natural reduction of PAHs and associated toxicity over time in non-disturbed areas of the sludge lagoon indicated MNA activity. The microorganisms were initially isolated on minimal medium containing naphthalene as the sole carbon and energy source. Fungal isolates were then maintained on MEA and identified based on microscopic examination and BIOLOG{reg_sign}. The analysis identified several of the fungal isolates as belonging to the genera Penicillium, Paecilomyces, Aspergillus, and Eupenicillium. Yeasts included Candida parapsilosis and C. fluvialitis. Further microbial characterization revealed that several isolates were capable of rowing on acidified media of pH 4, 3, and 2.5. Over twenty percent of the fungi demonstrated growth as low as pH 2.5. Of the 43 isolates examined, 24 isolates exhibited growth at 5 C. Nine of the fungal isolates exhibiting growth at 5 C were then …
Date: January 26, 2010
Creator: Brigmon, R.; Abe, M.; Johnson, B.; Simpson, W. & Mckinsey, P.
Object Type: Book
System: The UNT Digital Library
Simple Model of the (alpha)(omega) Dynamo: Self-Excited Spheromaks (open access)

Simple Model of the (alpha)(omega) Dynamo: Self-Excited Spheromaks

The astrophysical {alpha}{omega} dynamo converting angular momentum to magnetic energy can be interpreted as a self-excited Faraday dynamo together with magnetic relaxation coupling the dynamo poloidal field to the toroidal field produced by dynamo currents. Since both toroidal and poloidal fields are involved, the system can be modeled as helicity creation and transport, in a spheromak plasma configuration in quasi-equilibrium on the time scale of changes in magnetic energy. Neutral beams or plasma gun injection across field lines could create self-excited spheromaks in the laboratory.
Date: January 26, 2010
Creator: Fowler, T K
Object Type: Report
System: The UNT Digital Library
Alternate Alpha Induced Reactions for NIF Radiochemistry (open access)

Alternate Alpha Induced Reactions for NIF Radiochemistry

Radiochemical analysis of NIF capsule residues has been identified as a potential diagnostic of NIF capsule performance. In particular, alpha-induced nuclear reactions that occur on tracer elements added to the NIF capsule have been shown through simulation to be a very sensitive diagnostic for mix. The short range of the alpha particles makes them representative of the hot spot where they are created through the fusion of deuterium and tritium. Reactions on elements doped into the innermost part of the capsule ablator would therefore be sensitive to material that had mixed into the hot spot. Radiochemical determinations of activated detector elements may perhaps be the only true measure of mix that occurs in a NIF capsule, particularly in cases when the capsule fails.
Date: February 26, 2010
Creator: Shaughnessy, D A; Moody, K J & Bernstein, L A
Object Type: Report
System: The UNT Digital Library
Analytical Data Report of Grab Samples Collected From 200-ZP-1 Remedial Action Wells (open access)

Analytical Data Report of Grab Samples Collected From 200-ZP-1 Remedial Action Wells

This is an analytical data report prepared for CHPRC from grab samples received for 200-ZP-1 operable unit.
Date: February 26, 2010
Creator: Lindberg, Michael J.
Object Type: Report
System: The UNT Digital Library
Comprehensive Characterization of Voids and Microstructure in TATB-based Explosives from 10 nm to 1 cm: Effects of Temperature Cycling and Compressive Creep (open access)

Comprehensive Characterization of Voids and Microstructure in TATB-based Explosives from 10 nm to 1 cm: Effects of Temperature Cycling and Compressive Creep

This paper outlines the characterization of voids and Microstructure in TATB-based Explosives over several orders of magnitude, from sizes on the order of 10 nm to about 1 cm. This is accomplished using ultra small angle x-ray scattering to investigate voids from a few nm to a few microns, ultra small angle neutron scattering for voids from 100 nm to 10 microns, and x-ray computed microtomography to investigate microstructure from a few microns to a few centimeters. The void distributions of LX-17 are outlined, and the microstructure of LX-17 is presented. Temperature cycling and compressive creep cause drastically different damage to the microstructure. Temperature cycling leads to a volume expansion (ratchet growth) in TATB-based explosives, and x-ray scattering techniques that are sensitive to sizes up to a few microns indicated changes to the void volume distribution that had previously accounted for most, but not all of the change in density. This paper presents the microstructural damage larger than a few microns caused by ratchet growth. Temperature cycling leads to void creation in the binder poor regions associated with the interior portion of formulated prills. Conversely, compressive creep causes characteristically different changes to microstructure; fissures form at binder-rich prill boundaries prior …
Date: February 26, 2010
Creator: Willey, T. M.; Lauderbach, L.; Gagliardi, F.; Cunningham, B.; Lorenz, K. T.; Lee, J. I. et al.
Object Type: Article
System: The UNT Digital Library
The Effects of Degraded Digital Instrumentation and Control Systems on Human-system Interfaces and Operator Performance: HFE Review Guidance and Technical Basis (open access)

The Effects of Degraded Digital Instrumentation and Control Systems on Human-system Interfaces and Operator Performance: HFE Review Guidance and Technical Basis

New and advanced reactors will use integrated digital instrumentation and control (I&C) systems to support operators in their monitoring and control functions. Even though digital systems are typically highly reliable, their potential for degradation or failure could significantly affect operator performance and, consequently, impact plant safety. The U.S. Nuclear Regulatory Commission (NRC) supported this research project to investigate the effects of degraded I&C systems on human performance and plant operations. The objective was to develop human factors engineering (HFE) review guidance addressing the detection and management of degraded digital I&C conditions by plant operators. We reviewed pertinent standards and guidelines, empirical studies, and plant operating experience. In addition, we conducted an evaluation of the potential effects of selected failure modes of the digital feedwater system on human-system interfaces (HSIs) and operator performance. The results indicated that I&C degradations are prevalent in plants employing digital systems and the overall effects on plant behavior can be significant, such as causing a reactor trip or causing equipment to operate unexpectedly. I&C degradations can impact the HSIs used by operators to monitor and control the plant. For example, sensor degradations can make displays difficult to interpret and can sometimes mislead operators by making it …
Date: February 26, 2010
Creator: O'Hara, J. M. & W. Gunther, G. Martinez-Guridi
Object Type: Report
System: The UNT Digital Library
Predicting laser-induced bulk damage and conditioning for deuterated potassium di-hydrogen phosphate crystals using ADM (absorption distribution model) (open access)

Predicting laser-induced bulk damage and conditioning for deuterated potassium di-hydrogen phosphate crystals using ADM (absorption distribution model)

We present an empirical model that describes the experimentally observed laser-induced bulk damage and conditioning behavior in deuterated Potassium dihydrogen Phosphate (DKDP) crystals in a self-consistent way. The model expands on an existing nanoabsorber precursor model and the multi-step absorption mechanism to include two populations of absorbing defects, one with linear absorption and another with nonlinear absorption. We show that this model connects previously uncorrelated small-beam damage initiation probability data to large-beam damage density measurements over a range of ns pulse widths relevant to ICF lasers such as the National Ignition Facility (NIF). In addition, this work predicts the damage behavior of laser-conditioned DKDP and explains the upper limit to the laser conditioning effect. The ADM model has been successfully used during the commissioning and early operation of the NIF.
Date: February 26, 2010
Creator: Liao, Z. M.; Spaeth, M. L.; Manes, K.; Adams, J. J. & Carr, C. W.
Object Type: Article
System: The UNT Digital Library
Review of the IEEE Standard for Computerized Operating Procedure Systems (open access)

Review of the IEEE Standard for Computerized Operating Procedure Systems

Increasingly nuclear power plant procedures, such as emergency operating procedures, are being presented in computer form with functionality to support operator use and management of the procedures. The U.S. Nuclear Regulatory Commission (NRC) currently has guidance for the review of computer-based procedures (CBPs); however, there remain CBP functions and human performance issues for which up-to-date guidance is lacking. The Institute of Electrical and Electronics Engineers (IEEE) has initiated a standard development effort to address the human factors engineering (HFE) aspects of CBP systems. When completed, it may provide guidance to supplement the NRC staff's review criteria. The purpose of our study was to evaluate the suitability of the IEEE Standard for use in the NRC's HFE safety reviews of CBP systems and to ensure that the guidance meets the NRC's standard for scientific and engineering rigor used in its own guidance development efforts. We established the following criteria with which to evaluate the Standard: (1) it should meet an existing need of NRC reviewers, (2) it should be based in sound HFE principles, (3) it should be thoroughly peer-reviewed, and (4) it should address CBP-related human performance issues identified in the literature. This report describes the methodology we used to …
Date: February 26, 2010
Creator: O'Hara, J. & Higgins, J.
Object Type: Report
System: The UNT Digital Library
TANK OPERATIONS CONTRACT CONSTRUCTION MANAGEMENT METHODOLOGY (open access)

TANK OPERATIONS CONTRACT CONSTRUCTION MANAGEMENT METHODOLOGY

None
Date: February 26, 2010
Creator: Lesko, K. F. & Berriochoa, M. V.
Object Type: Article
System: The UNT Digital Library
TANK OPERATIONS CONTRACT CONSTRUCTION MANAGEMENT METHODOLOGY UTILIZING THE AGENCY METHOD OF CONSTRUCTION MANAGEMENT (open access)

TANK OPERATIONS CONTRACT CONSTRUCTION MANAGEMENT METHODOLOGY UTILIZING THE AGENCY METHOD OF CONSTRUCTION MANAGEMENT

Washington River Protection Solutions, LLC (WRPS) has faced significant project management challenges in managing Davis-Bacon construction work that meets contractually required small business goals. The unique challenge is to provide contracting opportunities to multiple small business constructioin subcontractors while performing high hazard work in a safe and productive manner. Previous to the WRPS contract, construction work at the Hanford Tank Farms was contracted to large companies, while current Department of Energy (DOE) Contracts typically emphasize small business awards. As an integral part of Nuclear Project Management at Hanford Tank Farms, construction involves removal of old equipment and structures and installation of new infrastructure to support waste retrieval and waste feed delivery to the Waste Treatment Plant. Utilizing the optimum construction approach ensures that the contractors responsible for this work are successful in meeting safety, quality, cost and schedule objectives while working in a very hazardous environment. This paper descirbes the successful transition from a traditional project delivery method that utilized a large business general contractor and subcontractors to a new project construction management model that is more oriented to small businesses. Construction has selected the Agency Construction Management Method (John E Schaufelberger, Len Holm, "Management of Construction Projects, A Constructor's …
Date: February 26, 2010
Creator: Lesko, K. F. & Berriochoa, M. V.
Object Type: Article
System: The UNT Digital Library
Technetium Waste Form Development Progress Report (open access)

Technetium Waste Form Development Progress Report

The approach being followed to evaluate the use of an iron-based alloy waste form to immobilize the Tc-bearing waste streams generated during the aqueous and electrochemical processing of used fuel that is being studied in the DOE Advanced Fuel Cycle Initiative (AFCI) is presented in this report. The objective is to develop an alloy waste form that provides high waste loading within waste form processing limitations, meets waste form performance requirements for durability and the long-term retention of radionuclides, and can be produced with consistent physical, chemical, and radiological properties that meet regulatory acceptance requirements for disposal. Microanalysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) was used to analyze non-radioactive Fe-Mo-Re samples. A sample was prepared for SEM; however, significant unforeseen instrument problems led to delays in conducting the detailed work. The TEM was not available for this particular sample and therefore only preliminary SEM work can be reported. The results are in agreement with previous studies [Ebert 2009]; however, a rhenium-rich region within the Re-Mo phase is clearly visible.
Date: February 26, 2010
Creator: Buck, Edgar C.
Object Type: Report
System: The UNT Digital Library
He Transport and Fate of Tempered Martensitic Steels: Summary of Recent TEM Observations (open access)

He Transport and Fate of Tempered Martensitic Steels: Summary of Recent TEM Observations

As an extension of prior work [1-4], we summarize recent observations made on a He-implanted tempered martensitic steel (TMS), F82H mod 3, irradiated in the HFIR, in both as-tempered (AT) and cold-worked (CW) conditions. A novel implantation technique was used to uniformly inject He into 3-mm diameter TEM discs to depths ranging from ≈ 5-8 µm. The He is generated by two-step transmutation reactions in Ni contained in a NiAl coating layer adjacent to paired 3 mm TEM discs. NiAl layers from 1 to 4 μm thick produced He/dpa ratios between 5 and 40 appm/dpa. The irradiations were at temperatures of 300, 400 and 500°C from 3.9 to 9 dpa and 90 to 380 appm He. Electron transparent samples were prepared by a cross-sectional thinning technique that allowed investigating microstructural evolution over a range of implantation depths. Irradiation of the AT alloy to 9 dpa at 500°C and 380 appm He resulted in relatively large, faceted cavities, that are likely voids, along with a much higher density of smaller He bubbles. The cavities were most often aligned in pearl necklace like strings, presumably due to their formation on pre-existing dislocations. A finer distribution of cavities was also present on precipitate …
Date: February 26, 2010
Creator: Edwards, Danny J.; Kurtz, Richard J.; Odette, G Robert & Yamamoto, Takuya
Object Type: Report
System: The UNT Digital Library
Calcifying Cyanobacteria - The Potential of Biomineralization for Carbon Capture and Storage (open access)

Calcifying Cyanobacteria - The Potential of Biomineralization for Carbon Capture and Storage

Employment of cyanobacteria in biomineralization of carbon dioxide by calcium carbonate precipitation offers novel and self-sustaining strategies for point-source carbon capture and sequestration. Although details of this process remain to be elucidated, a carbon-concentrating mechanism, and chemical reactions in exopolysaccharide or proteinaceous surface layers are assumed to be of crucial importance. Cyanobacteria can utilize solar energy through photosynthesis to convert carbon dioxide to recalcitrant calcium carbonate. Calcium can be derived from sources such as gypsum or industrial brine. A better understanding of the biochemical and genetic mechanisms that carry out and regulate cynaobacterial biomineralization should put us in a position where we can further optimize these steps by exploiting the powerful techniques of genetic engineering, directed evolution, and biomimetics.
Date: March 26, 2010
Creator: Jansson, Christer G. & Northen, Trent
Object Type: Article
System: The UNT Digital Library
Calculation of Ambient (H*(10)) and Personal (Hp(10)) Dose Equivalent from a 252Cf Neutron Source (open access)

Calculation of Ambient (H*(10)) and Personal (Hp(10)) Dose Equivalent from a 252Cf Neutron Source

The purpose of this calculation is to calculate the neutron dose factors for the Sr-Cf-3000 neutron source that is located in the 318 low scatter room (LSR). The dose factors were based on the dose conversion factors published in ICRP-21 Appendix 6, and the Ambient dose equivalent (H*(10)) and Personal dose equivalent (Hp(10)) dose factors published in ICRP Publication 74.
Date: March 26, 2010
Creator: Traub, Richard J.
Object Type: Report
System: The UNT Digital Library
Calibration of the Total Carbon Column Observing Network using Aircraft Profile Data (open access)

Calibration of the Total Carbon Column Observing Network using Aircraft Profile Data

The Total Carbon Column Observing Network (TCCON) produces precise measurements of the column average dry-air mole fractions of CO{sub 2}, CO, CH{sub 4}, N{sub 2}O and H{sub 2}O at a variety of sites worldwide. These observations rely on spectroscopic parameters that are not known with sufficient accuracy to compute total columns that can be used in combination with in situ measure ments. The TCCON must therefore be calibrated to World Meteorological Organization (WMO) in situ trace gas measurement scales. We present a calibration of TCCON data using WMO-scale instrumentation aboard aircraft that measured profiles over four TCCON stations during 2008 and 2009. The aircraft campaigns are the Stratosphere-Troposphere Analyses of Regional Transport 2008 (START-08), which included a profile over the Park Falls site, the HIAPER Pole-to-Pole Observations (HIPPO-1) campaign, which included profiles over the Lamont and Lauder sites, a series of Learjet profiles over the Lamont site, and a Beechcraft King Air profile over the Tsukuba site. These calibrations are compared with similar observations made during the INTEX-NA (2004), COBRA-ME (2004) and TWP-ICE (2006) campaigns. A single, global calibration factor for each gas accurately captures the TCCON total column data within error.
Date: March 26, 2010
Creator: Wunch, Debra; Toon, Geoffrey C.; Wennberg, Paul O.; Wofsy, Steven C.; Stephens, Britton B.; Fischer, Marc L. et al.
Object Type: Article
System: The UNT Digital Library
Effects of Temperature and Contamination on Mpcms Electrodes in 241-Ay-101 and 241-an-107 Tank Waste Simulants (open access)

Effects of Temperature and Contamination on Mpcms Electrodes in 241-Ay-101 and 241-an-107 Tank Waste Simulants

This report documents the results of tests designed to characterize the relationship between temperature and the measured potential of electrodes installed on multi-probe corrosion monitoring systems in waste tanks. This report also documents the results of tests designed to demonstrate the impact of liquid in-leakage into electrode bodies as well as the contamination of primary reference electrodes by diffusion through the electrode tip.
Date: March 26, 2010
Creator: Dahl, M. M.; Philo, S. L.; Edgemon, G. L.; Bell, J. L. S. & Moore, C. G.
Object Type: Report
System: The UNT Digital Library
FPGA Based Real-time Network Traffic Analysis using Traffic Dispersion Patterns (open access)

FPGA Based Real-time Network Traffic Analysis using Traffic Dispersion Patterns

The problem of Network Traffic Classification (NTC) has attracted significant amount of interest in the research community, offering a wide range of solutions at various levels. The core challenge is in addressing high amounts of traffic diversity found in today's networks. The problem becomes more challenging if a quick detection is required as in the case of identifying malicious network behavior or new applications like peer-to-peer traffic that have potential to quickly throttle the network bandwidth or cause significant damage. Recently, Traffic Dispersion Graphs (TDGs) have been introduced as a viable candidate for NTC. The TDGs work by forming a network wide communication graphs that embed characteristic patterns of underlying network applications. However, these patterns need to be quickly evaluated for mounting real-time response against them. This paper addresses these concerns and presents a novel solution for real-time analysis of Traffic Dispersion Metrics (TDMs) in the TDGs. We evaluate the dispersion metrics of interest and present a dedicated solution on an FPGA for their analysis. We also present analytical measures and empirically evaluate operating effectiveness of our design. The mapped design on Virtex-5 device can process 7.4 million packets/second for a TDG comprising of 10k flows at very high accuracies …
Date: March 26, 2010
Creator: Khan, F.; Gokhale, M. & Chuah, C. N.
Object Type: Article
System: The UNT Digital Library
Integrated Nucleosynthesis in Neutrino Driven Winds (open access)

Integrated Nucleosynthesis in Neutrino Driven Winds

Although they are but a small fraction of the mass ejected in core-collapse supernovae, neutrino-driven winds (NDWs) from nascent proto-neutron stars (PNSs) have the potential to contribute significantly to supernova nucleosynthesis. In previous works, the NDW has been implicated as a possible source of r-process and light p-process isotopes. In this paper we present time-dependent hydrodynamic calculations of nucleosynthesis in the NDW which include accurate weak interaction physics coupled to a full nuclear reaction network. Using two published models of PNS neutrino luminosities, we predict the contribution of the NDW to the integrated nucleosynthetic yield of the entire supernova. For the neutrino luminosity histories considered, no true r-process occurs in the most basic scenario. The wind driven from an older 1.4M{sub {circle_dot}} model for a PNS is moderately neutron-rich at late times however, and produces {sup 87}Rb, {sup 88}Sr, {sup 89}Y, and {sup 90}Zr in near solar proportions relative to oxygen. The wind from a more recently studied 1.27M{sub {circle_dot}} PNS is proton-rich throughout its entire evolution and does not contribute significantly to the abundance of any element. It thus seems very unlikely that the simplest model of the NDW can produce the r-process. At most, it contributes to the …
Date: March 26, 2010
Creator: Roberts, L F; Woosley, S E & Hoffman, R D
Object Type: Article
System: The UNT Digital Library