Final report: Efficient thyratron modulator project (open access)

Final report: Efficient thyratron modulator project

The purpose of this program was to examine methods of increasing the efficiency of producing pulses to drive Klystrons in the 150 MW range. This may include 2 Klystrons in the 75 MW range. Specific methods of interest to improve the pulse efficiency were the use of a circuit to add energy to the tail of the pulse, the use of a bipyrimidal transformer, and the use of gas insulation as a means of improving the pulse shape. These methods were investigated using both thyratron and IGBT switching. The low cost designs developed in this work consisted of low voltage designs which don't require the oil immersion. These designs can be ''hot tuned'' based on the use of simple, tunable inductors.
Date: November 26, 1999
Creator: Adler, R. J.; Richter-Sand, R. J. & Gregg, C. W.
Object Type: Report
System: The UNT Digital Library
Evaporative Evolution of Brines from Synthetic Topoah Spring Tuff Pore Water, Yucca Mountain, NV (open access)

Evaporative Evolution of Brines from Synthetic Topoah Spring Tuff Pore Water, Yucca Mountain, NV

We are investigating the evaporation of pore water representative of the designated high-level-nuclear-waste repository at Yucca Mountain, NV to predict the range of brine compositions that may contact waste containers. These brines could form potentially corrosive thin films on the containers and impact their long-term integrity. Here we report the geochemistry of a relatively complex synthetic Topopah Spring Tuff pore water that was progressively evaporated in a series of experiments. The experiments were conducted in a closed vessel, heated to 95 C, and purged with atmospheric CO{sub 2}. Aqueous samples of the evaporating solution were taken and analyzed to determine the evolving water chemistry, and the final solid precipitate was analyzed by X-ray diffraction. The synthetic Topopah Spring Tuff water evolved towards a complex brine that contains about 3 mol% SO{sub 4}, and 2 mol% Ca, 3 mol% K, 5 mol% NO{sub 3}, 40 mol% Cl, and 47 mol% Na. Trends in the solution data and identification of CaSO{sub 4} solids (anhydrite and bassanite) suggest that fluorite, carbonate, sulfate, and Mg-silicate precipitation minimize the corrosion potential of ''sulfate type pore water'' by removing F, Ca, and Mg during the early stages of evaporation.
Date: November 26, 2002
Creator: Alai, M & Carroll, S
Object Type: Article
System: The UNT Digital Library
Evaluating GC/MS Performance (open access)

Evaluating GC/MS Performance

Evaluating the chemical background in the GC/MS system (system background) and solvent purity. This procedure will allow the analyst to verify that the GC/MS is free of chemical interferences or contamination and verify the solvent being utilized is free of interferences - Conduct a GC/MS analysis without injecting a solvent (system background) and Conduct a GC/MS analysis inject 1uL of CH2Cl2 solvent (Solvent background). GC conditions: (1) Injector Temperature (C): Injector Temperature is typically set at 250; (2) Transferline Temperature (C) - The Transferline Temperature is typically set at 280 C; (3) Constant flow (Sec./cm2) - This value, in seconds per cubic cm. Typically, set at 32; (4) Splitless mode (Sec.) - This value, in seconds, is the time before the purge valve opens. Typically, set at 45 seconds; (5) Starting Temperature (C): The Starting Temperature value can be set at 40 C; (6) Hold Time 1 (Min.) - Hold Time 1 is the amount of time, in minutes at the Starting Temperature that Ramp 1 Temperature is held. Typically set at 3 minutes; (7) Ramp 1 Rate (C/Min.) - Ramp 1 Rate is the temperature rise per unit time and has a typically value of 8 C per minute …
Date: November 26, 2006
Creator: Alcaraz, A. & Dougan, A.
Object Type: Report
System: The UNT Digital Library
Method to prepare Semtex (open access)

Method to prepare Semtex

This procedure requires the binder and uncoated RDX be prepared in separate steps, see Figure 1: (1) The binder and dye are mixed by agitation with a water-insoluble organic solvent (e.g., toluene), I; (2) The RDX/PETN is agitated thoroughly with water, II; (3) The binder solution I is added to the RDX/water mixture at II with thorough mixing to form a slurry III; (4) In the next step the solvent is distilled off at IV leaving resulting granules; (5) The next step is followed by filtration at V, which may be done by vacuum; (6) The composition is then dried at VI to a dough-like consistency.
Date: November 26, 2006
Creator: Alcaraz, A. & Dougan, A.
Object Type: Report
System: The UNT Digital Library
Chemistry, phase formation, and catalytic activity of thin palladium-containing oxide films synthesized by plasma-assisted physical vapor deposition (open access)

Chemistry, phase formation, and catalytic activity of thin palladium-containing oxide films synthesized by plasma-assisted physical vapor deposition

The chemistry, microstructure, and catalytic activity of thin films incorporating palladium were studied using scanning and transmission electron microscopies, X-ray diffraction, spectrophotometry, 4-point probe and catalytic tests. The films were synthesized using pulsed filtered cathodic arc and magnetron sputter deposition, i.e. techniques far from thermodynamic equilibrium. Catalytic particles were formed by thermally cycling thin films of the Pd-Pt-O system. The evolution and phase formation in such films as a function of temperature were discussed in terms of the stability of PdO and PtO2 in air. The catalytic efficiency was found to be strongly affected by the chemical composition, with oxidized palladium definitely playing a major role in the combustion of methane. Reactive sputter deposition of thin films in the Pd-Zr-Y-O system allowed us forming microstructures ranging from nanocrystalline zirconia to palladium nanoparticles embedded in a (Zr,Y)4Pd2O matrix. The sequence of phase formation is put in relation to simple thermodynamic considerations.
Date: November 26, 2010
Creator: Anders, Andre
Object Type: Article
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
DETAILED ANALYSIS OF THE MOST PROMISING ALTERNATIVES TO USING GRANULAR ACTIVATED CARBON TO TREAT 200-ZP-1 GROUNDWATER AND 200-PW-1 SOIL VAPOR (open access)

DETAILED ANALYSIS OF THE MOST PROMISING ALTERNATIVES TO USING GRANULAR ACTIVATED CARBON TO TREAT 200-ZP-1 GROUNDWATER AND 200-PW-1 SOIL VAPOR

This document presents a detailed evaluation of selected alternative treatment options to granular activated carbon (GAC) for removing carbon tetrachloride generated from the groundwater pump-and-treat system at the 200-ZP-I Operable Unit (OU) in the 200 West Area of the Hanford Site. This evaluation of alternative treatment options to GAC is also applicable to the vadose zone soil vapor extraction (SVE) system at the 200-PW-l OU, which is also located in the Hanford Site's 200 West Area.
Date: November 26, 2007
Creator: BYRNES ME, KALMAR JA
Object Type: Report
System: The UNT Digital Library
Results For The Third Quarter 2013 Tank 50 WAC Slurry Sample (open access)

Results For The Third Quarter 2013 Tank 50 WAC Slurry Sample

This report details the chemical and radionuclide contaminant results for the characterization of the 2013 Third Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC) in effect at that time. Information from this characterization will be used by DWPF & Saltstone Facility Engineering (DSFE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System.
Date: November 26, 2013
Creator: Bannochie, Christopher J.
Object Type: Report
System: The UNT Digital Library
Low Floor Americans with Disabilities Compliant Alternate Fuel Vehicle Project (open access)

Low Floor Americans with Disabilities Compliant Alternate Fuel Vehicle Project

This project developed a low emission, cost effective, fuel efficient, medium-duty community/transit shuttle bus that meets American's with Disabilities Act (ADA) requirements and meets National Energy Policy Act requirements (uses alternative fuel). The Low Profile chassis, which is the basis of this vehicle is configured to be fuel neutral to accommodate various alternative fuels. Demonstration of the vehicle in Yellowstone Park in summer (wheeled operation) and winter (track operation) demonstrated the feasibility and flexibility for this vehicle to provide year around operation throughout the Parks system as well as normal transit operation. The unique configuration of the chassis which provides ADA access with a simple ramp and a flat floor throughout the passenger compartment, provides maximum access for all passengers as well as maximum flexibility to configure the vehicle for each application. Because this product is derived from an existing medium duty truck chassis, the completed bus is 40-50% less expensive than existing low floor transit buses, with the reliability and durability of OEM a medium duty truck.
Date: November 26, 2004
Creator: Bartel, James
Object Type: Report
System: The UNT Digital Library
Optical Design for Extremely Large Telescope Adaptive Optics Systems (open access)

Optical Design for Extremely Large Telescope Adaptive Optics Systems

Designing an adaptive optics (AO) system for extremely large telescopes (ELT's) will present new optical engineering challenges. Several of these challenges are addressed in this work, including first-order design of multi-conjugate adaptive optics (MCAO) systems, pyramid wavefront sensors (PWFS's), and laser guide star (LGS) spot elongation. MCAO systems need to be designed in consideration of various constraints, including deformable mirror size and correction height. The y,{bar y} method of first-order optical design is a graphical technique that uses a plot with marginal and chief ray heights as coordinates; the optical system is represented as a segmented line. This method is shown to be a powerful tool in designing MCAO systems. From these analyses, important conclusions about configurations are derived. PWFS's, which offer an alternative to Shack-Hartmann (SH) wavefront sensors (WFS's), are envisioned as the workhorse of layer-oriented adaptive optics. Current approaches use a 4-faceted glass pyramid to create a WFS analogous to a quad-cell SH WFS. PWFS's and SH WFS's are compared and some newly-considered similarities and PWFS advantages are presented. Techniques to extend PWFS's are offered: First, PWFS's can be extended to more pixels in the image by tiling pyramids contiguously. Second, pyramids, which are difficult to manufacture, can …
Date: November 26, 2003
Creator: Bauman, B J
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Two-Phase Emission Detector for Measuring Coherent Neutrino-Nucleus Scattering (open access)

Two-Phase Emission Detector for Measuring Coherent Neutrino-Nucleus Scattering

Coherent scattering is a flavor-blind, high-rate, as yet undetected neutrino interaction predicted by the Standard Model. We propose to use a compact (kg-scale), two-phase (liquid-gas) argon ionization detector to measure coherent neutrino scattering off nuclei. In our approach, neutrino-induced nuclear recoils in the liquid produce a weak ionization signal, which is transported into a gas under the influence of an electric field, amplified via electroluminescence, and detected by phototubes or avalanche diodes. This paper describes the features of the detector, and estimates signal and background rates for a reactor neutrino source. Relatively compact detectors of this type, capable of detecting coherent scattering, offer a new approach to flavor-blind detection of man-made and astronomical neutrinos, and may allow development of compact neutrino detectors capable of nonintrusive real-time monitoring of fissile material in reactors.
Date: November 26, 2003
Creator: Bernstein, A & Hagmann, C A
Object Type: Article
System: The UNT Digital Library
Sharing lessons learned - what have we learned? (open access)

Sharing lessons learned - what have we learned?

A set of viewgraphs for presenting what has been learned from experience with the Department of Energy`s Lessons Learned program, covering a brief history, the system and tools for sharing and accessing Lessons Learned, and how Lessons Learned can help the audience.
Date: November 26, 1997
Creator: Bickford, J. C.
Object Type: Article
System: The UNT Digital Library
Architectural Analysis of a LLNL LWIR Sensor System (open access)

Architectural Analysis of a LLNL LWIR Sensor System

None
Date: November 26, 2013
Creator: Bond, E J; Curry, J R; LaFortune, K N & Williams, A M
Object Type: Report
System: The UNT Digital Library
Microbiological Analysis of an Active Pilot-Scale Mobile Bioreactor Treating Organic Contaminants (open access)

Microbiological Analysis of an Active Pilot-Scale Mobile Bioreactor Treating Organic Contaminants

Samples were obtained for microbiological analysis from a granular activated carbon fluidized bed bioreactor (GAC-FBR). This GAC-FBR was in operation at a former manufactured gas plant (MGP) Site in Augusta Georgia for in situ groundwater bioremediation of organics. The samples included contaminated site groundwater, GAC-FBR effluent, and biofilm coated granular activated carbon at 5, 9, and 13 feet within the GAC-FBR column. The objective of this analysis was to correlate contaminant removal with microbiological activity within the GAC-FBR.
Date: November 26, 1997
Creator: Brigmon, R.L.
Object Type: Report
System: The UNT Digital Library
First Observation of An Excited Charm Baryon Decaying to Omega Charm Baryon at the BaBar Experiment (open access)

First Observation of An Excited Charm Baryon Decaying to Omega Charm Baryon at the BaBar Experiment

We have carried out a search for a charmed baryon {Omega}{sup *}{sub c} decaying to {Omega}{sup 0}{sub c} and a {gamma} where {Omega}{sub c} candidates are reconstructed using decay modes {Omega}{sup -}{pi}{sup +}(c1), {Omega}{sup -}{pi}{sup +}{pi}{sup 0}(c2), {Omega}{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup +}(c3) and {Xi}{sup -}K{sup -}{pi}{sup +}{pi}{sup +}(c4). This search is performed by analyzing integrated luminosity of 230.7 fb{sup -1} data collected by the BABAR detector at the Stanford Linear Accelerator Center. In decay channel {Omega}{sup *}{sub c} {yields} {Omega}{sup 0}{sub c}({Omega}{sup -}{pi}{sup +}){gamma} (C1), we observe a signal yield of 39.2{sup +9.8}{sub -9.1}(stat){+-}6.0(syst) events with a significance of 4.2 standard deviations. In decay channels {Omega}{sup *}{sub c} {yields} {Omega}{sup 0}{sub c}({Omega}{sup -}{pi}{sup +}{pi}{sup 0}){gamma} (C2) and {Omega}{sup *}{sub c} {yields} {Omega}{sup 0}{sub c}({Xi}{sup -}K{sup -}{pi}{sup +}{pi}{sup +}){gamma} (C4), we observe signal yields of 55.2{sup 16.1}{sub -15.2} {+-} 5.6 and 20.2{sup +9.3}{sub -8.5} {+-} 3.1 with significances of 3.4 and 2.0 {sigma}, respectively. As for the {Omega}{sup *}{sub c} {yields} {Omega}{sup 0}{sub c}({Omega}{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup +}){gamma} (C3) decay channel, we observe signal yields of -5.1{sup +5.3.8}{sub -4.7}{+-}1.0 without a positive significance. We assume the same production mechanism for the four decay channels of {Omega}{sup *}{sub c} studied. By combining …
Date: November 26, 2007
Creator: Bula, Rahmi & /SUNY, Albany
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Nondestructive, energy-dispersive, x-ray fluorescence analysis of product stream concentrations from reprocessed nuclear fuels (open access)

Nondestructive, energy-dispersive, x-ray fluorescence analysis of product stream concentrations from reprocessed nuclear fuels

Energy-dispersive x-ray fluorescence analysis (XRFA) can be used to measure nondestructively pure and mixed U/Pu concentrations in process streams and hold tank solutions. The 122-keV gamma ray from /sup 57/Co excites the actinide K x rays which are detected by a HPGe detector. A computer- and disk-based analyzer system provides capability for making on-stream analyses, and the noninvasive measurement is easily adapted directly to appropriate sized pipes used in a chemical reprocessing plant. Measurement times depend on concentration and purpose but vary from 100 to 500s for process control of strong to weak solutions. Accountability measurements require better accuracy thus more time; and for solutions containing plutonium, require a measurement of the solution radioactivity made with an automatic shutter that eclipses the two exciting sources. Plutonium isotopic abundances can also be obtained. Concentrations in single or dual element solutions from less than 1 g/l to over 200 g/l are determined to an accuracy of 0.2% after calibration of the system. For mixed solutions the unknown ratio of U to Pu is linearly related to the net U/Pu K x-ray intensities. Concentration values for ratios different than the calibration ratio require only small corrections to the values derived from a calibration …
Date: November 26, 1979
Creator: Camp, D. C. & Ruhter, W. D.
Object Type: Article
System: The UNT Digital Library
Pion correlations as a function of atomic mass in heavy ion collisions (open access)

Pion correlations as a function of atomic mass in heavy ion collisions

The method of two pion interferometry was used to obtain source-size and lifetime parameters for the pions produced in heavy ion collisions. The systems used were 1.70 {center dot} A GeV {sup 56}Fe + Fe, 1.82 {center dot} A GeV {sup 40}Ar + KCl and 1.54 {center dot} A GeV {sup 93}Nb + Nb, allowing for a search for dependences on the atomic number. Two acceptances (centered, in the lab., at {approximately} 0{degrees} and 45{degrees}) were used for each system, allowing a search for dependences on the viewing angle. The correlation functions were calculated by comparing the data samples to background (or reference) samples made using the method of event mixing, where pions from different events are combined to produce a data sample in which the Bose-Einstein correlation effect is absent. The effect of the correlation function on the background samples is calculated, and a method for weighting the events to remove the residual correlation effect is presented. The effect of the spectrometer design on the measured correlation functions is discussed, as are methods for correcting for these effects during the data analysis. 58 refs., 39 figs., 18 tabs.
Date: November 26, 1989
Creator: Chacon, A.D.
Object Type: Report
System: The UNT Digital Library
Reduced order modelling for dynamic simulations: LDRD feasibility study final report (open access)

Reduced order modelling for dynamic simulations: LDRD feasibility study final report

None
Date: November 26, 2012
Creator: Chand, K. K.; Henshaw, W. D. & Vassilevska, T. K.
Object Type: Report
System: The UNT Digital Library
Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques (open access)

Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques

The project's primary objective was to enhance domestic petroleum production by demonstration and transfer of horizontal drilling technology in the Paradox Basin, Utah, Colorado, Arizona, and New Mexico. If this project can demonstrate technical and economic feasibility, then the technique can be applied to approximately 100 additional small fields in the Paradox Basin alone, and result in increased recovery of 25 to 50 million barrels (4-8 million m3) of oil. This project was designed to characterize several shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation, choose the best candidate(s) for a pilot demonstration project to drill horizontally from existing vertical wells, monitor well performance(s), and report associated validation activities.
Date: November 26, 2001
Creator: Chidsey, Thomas C., Jr.; Eby, David E. & Wray, Laural L.
Object Type: Report
System: The UNT Digital Library
A STUDY OF THE RELATIONSHIP OF GEOLOGICAL FORMATION TO THE NORM (open access)

A STUDY OF THE RELATIONSHIP OF GEOLOGICAL FORMATION TO THE NORM

Naturally occurring radioactive materials (NORM) are everywhere and we are constantly exposed to it. Natural radiation has been around since the beginning of the Earth and is found in our bodies, our food, and in the products we use. This study investigates the presence and activity of naturally occurring radioactive materials contained in produced water which is associated with oil and gas exploration. Specifically the principal radionuclide used to measure NORM was radium. We also measured , where possible, other parameters which may have had an effect on the NORM activity. Produced water samples from two different oil field sites, Fausse Pointe and North Broussard, have been used as test sites for this water analysis study. The overall purpose was to determine the specific, selected parameters associated with the produced waters, which are defined as the waters which are brought to the surface along with oil and natural gas. This study is also a precursor in an attempt to predict the activity of naturally occurring radioactive materials and the other factors which may affect the activity and/or occurrence of NORM in produced water samples. A control site used for comparison, was Lake Kernan on the Southern University Campus. The average …
Date: November 26, 2002
Creator: Chriss, Derald & Bursh, Talmage P.
Object Type: Report
System: The UNT Digital Library
Reference: SR-TP-3625 (open access)

Reference: SR-TP-3625

The reference letter dated October 4, 1956, requested that they review the possibilities of a crippling accident in 232-H and the measures which might be taken to minimize the loss in tritium production associated with such an accident be reviewed. These subjects have been reviewed in considerable detail and the authors feel that the chances of a crippling accident are quite remote. In arriving at this conclusion, the entire process was reviewed and the following three incidents were selected as having the most serious potential. (1) a tank containing tritium at subatmospheric pressure develops a leak and becomes contaminated with air equalized to atmospheric pressure; (2) a flange is removed inadvertently or a nozzle breaks on a tank containing tritium at 15 psig; (3) the water jacket on the extraction furnace ruptures internally, particularly when the charge is molten. From the foregoing, it may be concluded that a serious accident in one line is unlikely to shut down the other from the standpoint of either physical damage or serious contamination. It should be recognized that some outage, perhaps a matter of days or even weeks, could result while safety of operation is assured. Insofar as procurement of long delivery equipment …
Date: November 26, 1956
Creator: Christl, R. J.
Object Type: Report
System: The UNT Digital Library
Amines as Extractants--Survey of the Descriptive and Fundamental Extraction Chemistry (open access)

Amines as Extractants--Survey of the Descriptive and Fundamental Extraction Chemistry

Both the study and the use of extractions with highmolecular-weight amines (including quaternary ammoniums) in organic solution are increasing extensively. While equilibria have been measured in the extraction of an increasing range of acids and Aetal ions, a difficulty remains unresolved in that the amine concentration powerdependence of extraction often indicates a different stoichiometry of the complex existing in the organic phase than do limiting loading and other considerations. Nevertheless, amine extraction serves as a useful tool in studying complexes formed in aqueous systems. Process applications have progressed especially in nitrate and chioride systems, in addition to the sulfate systems first emphasized. Systematic surveys, together with information accruing from process development, have extended the ranges of extractions that can be correlated in usefully generalized patterns, which in turn should accelerate the development of new applications. However, many more areas remain to be surveyed before the many pertinent variables will have been covered. New amines of all classes have become available at commercial, development, or researchsample levels, while a few previously promising amines have become less available. Descriptions and current sources are reviewed. (auth)
Date: November 26, 1963
Creator: Coleman, C. F.
Object Type: Report
System: The UNT Digital Library
Neutron star accretion and the neutrino fireball (open access)

Neutron star accretion and the neutrino fireball

The mixing necessary to explain the ``Fe`` line widths and possibly the observed red shifts of 1987A is explained in terms of large scale, entropy conserving, up and down flows (calculated with a smooth particle 2-D code) taking place between the neutron star and the explosion shock wave due to the gravity and neutrino deposition. Depending upon conditions of entropy and mass flux further accretion takes place in single events, similar to relaxation oscillator, fed by the downward flows of low entropy matter. The shock, in turn, is driven by the upflow of the buoyant high entropy bubbles. Some accretion events will reach a temperature high enough to create a neutrino ``fireball,`` a region hot enough, 11 Mev, so as to be partially opaque to its own (neutrino) radiation. The continuing neutrino deposition drives the explosion shock until the entropy of matter flowing downwards onto the neutron star is high enough to prevent further accretion. This process should result in a robust supernova explosion.
Date: November 26, 1991
Creator: Colgate, S. A.; Herant, M. E. & Benz, W.
Object Type: Article
System: The UNT Digital Library
Neutron star accretion and the neutrino fireball (open access)

Neutron star accretion and the neutrino fireball

The mixing necessary to explain the Fe'' line widths and possibly the observed red shifts of 1987A is explained in terms of large scale, entropy conserving, up and down flows (calculated with a smooth particle 2-D code) taking place between the neutron star and the explosion shock wave due to the gravity and neutrino deposition. Depending upon conditions of entropy and mass flux further accretion takes place in single events, similar to relaxation oscillator, fed by the downward flows of low entropy matter. The shock, in turn, is driven by the upflow of the buoyant high entropy bubbles. Some accretion events will reach a temperature high enough to create a neutrino fireball,'' a region hot enough, 11 Mev, so as to be partially opaque to its own (neutrino) radiation. The continuing neutrino deposition drives the explosion shock until the entropy of matter flowing downwards onto the neutron star is high enough to prevent further accretion. This process should result in a robust supernova explosion.
Date: November 26, 1991
Creator: Colgate, S.A. (Los Alamos National Lab., NM (United States)); Herant, M.E. (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)) & Benz, W. (Steward Observatory, Tucson, AZ (United States))
Object Type: Article
System: The UNT Digital Library