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A CAMAC system controlled by an IBM AT computer for time-resolved spectroscopy (open access)

A CAMAC system controlled by an IBM AT computer for time-resolved spectroscopy

An IBM AT computer interfaced to a small CAMAC system offers considerable power without the complexity and expense of a large general-purpose system. Our system for time-resolved spectroscopy features menu-driven FORTRAN-based software; high-resolution and high-speed (8K channels, 5-..mu..s fixed dead time) ADCs; segmentable histogram memories (24-bit counts) with large memory space for many histogram segments; independently variable separate histogram dwell times; remote control via a CAMAC serial highway; and ground isolation between the data acquisition equipment and control computer by means of fiber optics.
Date: January 1, 1987
Creator: Lindquist, L.O. & Moss, C.E.
System: The UNT Digital Library
Electroweak radiative corrections and neutral current phenomenology (open access)

Electroweak radiative corrections and neutral current phenomenology

Precision measurements of sin/sup 2/ theta/sub W/ including the effects of radiative corrections are surveyed. A world average sin/sup 2/ theta/sub W/ = 0.231 +- 0.004 is obtained. Comparison of deep-inelastic nu/sub ..mu../N scattering and m/sub W/ or m/sub Z/ is shown to test the standard model at the quantum loop level and constrain new physics. Implications for extra Z' bosons and grand unified theories are briefly discussed. 25 refs., 2 figs.
Date: March 1, 1987
Creator: Marciano, William J.
System: The UNT Digital Library
Integrated heat pipe-thermal storage system performance evaluation (open access)

Integrated heat pipe-thermal storage system performance evaluation

Performance verification tests of an integrated heat pipe-thermal energy storage system have been conducted. This system is being developed as a part of an Organic Rankine Cycle-Solar Dynamic Power System (ORC-SDPS) receiver for future space stations. The integrated system consists of potassium heat pipe elements that incorporate thermal energy storage (TES) canisters within the vapor space along with an organic fluid (toluene) heater tube used as the condenser region of the heat pipe. During the insolation period of the earth orbit, solar energy is delivered to the surface of the heat pipe elements of the ORC-SDPS receiver and is internally transferred by the potassium vapor for use and storage. Part of the thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of the orbit, the stored energy in the TES units is transferred by the potassium vapor to the toluene heater tube. A developmental heat pipe element was fabricated that employs axial arteries and a distribution wick connecting the wicked TES units and the heater to the solar insolation surface of the heat pipe. Tests were conducted to verify the heat pipe operation and to evaluate the heat …
Date: January 1, 1987
Creator: Keddy, E.; Sena, J.T. & Merrigan, M.
System: The UNT Digital Library
Results from the MAC Vertex chamber (open access)

Results from the MAC Vertex chamber

The design, construction, and performance characteristics of a high precision gaseous drift chamber made of thin walled proportional tubes are described. The device achieved an average spatial resolution of 45 ..mu..m in use for physics analysis with the MAC detector. The B-lifetime result obtained with this chamber is discussed.
Date: May 1, 1987
Creator: Nelson, H.N.
System: The UNT Digital Library
Waste-acceptance criteria for radioactive waste disposal (open access)

Waste-acceptance criteria for radioactive waste disposal

A method has been developed for establishing waste-acceptance criteria based on quantitative performance factors that characterize the confinement capabilities of a disposal facility for radioactive waste. The method starts from the objective of protecting public health and safety by assuring that disposal of the waste will not result in a radiation dose of any member of the general public, in either the short or long term, in excess of an established basic dose limit. A key aspect of the method is the introduction of a confinement factor that characterizes the overall confinement capability of a particular disposal facility and can be used for quantitative performance assessments as well as for establishing facility-specific waste-acceptance criteria. Confinement factors enable direct and simple conversion of a basic dose limit into waste-acceptance criteria, specified as concentration limits on rationuclides in the waste streams. Waste-acceptance criteria can be represented visually as activity/time plots for various waste streams. These plots show the concentrations of radionuclides in a waste stream as a function of time and permit a visual, quantitative assessment of long-term performance, relative risks from different radionuclides in the waste stream, and contributions from ingrowth. Application of the method to generic facility designs provides a …
Date: February 1, 1987
Creator: Gilbert, T. L. & Meshkov, N. K.
System: The UNT Digital Library
Timing stabilization for the SLC electron source (open access)

Timing stabilization for the SLC electron source

The timing stability required for the SLC electron source is determined by the energy acceptance of the electron damping ring. The jitter requirements for the gun pulse itself are somewhat mitigated by the subsequent bunching process. The desogn of the system by which a gun pulse stability of sigma approx. 20 ps is achieved is described, and experiments to measure the resulting energy stability under various bunching conditions are discussed.
Date: February 1, 1987
Creator: Clendenin, J. E.; Browne, M. J.; Gearhart, R. A.; Sheppard, J. C. & Sodja, J.
System: The UNT Digital Library
Review of the Advanced Toroidal Facility program (open access)

Review of the Advanced Toroidal Facility program

This report summarizes the history and design goals of the Advanced Toroidal Facility (ATF). The ATF is nearing completion at ORNL with device completion expected in May 1987 and first useful plasma operation in June/July 1987. ATF is a moderate-aspect-ratio torsatron, the world's largest stellarator facility with R = 2.1 m, ..cap alpha.. bar = 0.3 m and B = 2 T (5-s pulse) or 1 T (steady-state capability). It has been specifically designed to support the US tokamak program by studying important toroidal confinement issues in a similar magnetic geometry that allows external control of the magnetic configuration properties and their radial profiles: transform, shear, well depth, shaping, axis topology, etc. ATF will operate in a current-free model which allows separation of current-driven and pressure-driven plasma behavior. It also complements the world stellarator program in its magnetic configuration (between Heliotron-E and W VII-AS) and its capabilities (large size, good access, steady state capability, second stability access, etc.). For both roles ATF will require high-power long-pulse heating to carry out its physics goals since the high power NBI pulse is limited to 0.3 s. The ATF program focuses on demonstrating the principles of high-beta, steady-state operation in toroidal geometry through …
Date: February 25, 1987
Creator: Lyon, J.F. & Murakami, M.
System: The UNT Digital Library
SAS4A: A computer model for the analysis of hypothetical core disruptive accidents in liquid metal reactors (open access)

SAS4A: A computer model for the analysis of hypothetical core disruptive accidents in liquid metal reactors

To ensure that the public health and safety are protected under any accident conditions in a Liquid Metal Fast Breeder Reactor (LMFBR), many accidents are analyzed for their potential consequences. The SAS4A code system, described in this paper, provides such an analysis capability, including the ability to analyze low probability events such as the Hypothetical Core Disruptive Accidents (HCDAs). The SAS4A code system has been designed to simulate all the events that occur in a LMFBR core during the initiating phase of a Hypothetical Core Disruptive Accident. During such postulated accident scenarios as the Loss-of-Flow and Transient Overpower events, a large number of interrelated physical phenomena occur during a relatively short time. These phenomena include transient heat transfer and hydrodynamic events, coolant boiling and fuel and cladding melting and relocation. During to the strong neutronic feedback present in a nuclear reactor, these events can significantly influence the reactor power. The SAS4A code system is used in the safety analysis of nuclear reactors, in order to estimate the energetic potential of very low probability accidents. The results of SAS4A simulations are also used by reactor designers in order to build safer reactors and eliminate the possibility of any accident which could …
Date: January 1, 1987
Creator: Tentner, A. M.; Birgersson, G.; Cahalan, J. E.; Dunn, F. E.; Kalimullah & Miles, K. J.
System: The UNT Digital Library
Rare B-decays: Experimental prospects and problems (open access)

Rare B-decays: Experimental prospects and problems

We discuss the future prospects and experimental requirements for generic b-physics, with an emphasis on hadroproduction and on observation of CP violation.
Date: May 1, 1987
Creator: Bjorken, J. D.
System: The UNT Digital Library
Making transuranic assay measurements using modern controllers (open access)

Making transuranic assay measurements using modern controllers

This paper describes methodology and computer-controlled instrumentation developed at the Los Alamos National Laboratory that accurately performs nondestructive assays of large containers bearing transuranic wastes and nonradioactive matrix materials. These assay systems can measure fissile isotopes with 1-mg sensitivity and spontaneous neutron-emitting isotopes at a 10-mg sensitivity. The assays are performed by neutron interrogation, detection, and counting in a custom assay chamber. An International Business Machines Personal Computer (IBM-PC) is used to control the CAMAC-based instrumentation system that acquires the assay data. 6 refs., 7 figs.
Date: January 1, 1987
Creator: Kuckertz, T.H.; Caldwell, J.T.; Medvick, P.A.; Kunz, W.E. & Hastings, R.D.
System: The UNT Digital Library
Tests of Candidate Materials for Particle Bed Reactors (open access)

Tests of Candidate Materials for Particle Bed Reactors

Rhenium metal hot frits and zirconium carbide-coated fuel particles appear suitable for use in flowing hydrogen to at least 2000 K, based on previous tests. Recent tests on alternate candidate cooled particle and frit materials are described. Silicon carbide-coated particles began to react with rhenium frit material at 1600 K, forming a molten silicide at 2000 K. Silicon carbide was extensively attacked by hydrogen at 2066 K for 30 minutes, losing 3.25% of its weight. Vitrous carbon was also rapidly attacked by hydrogen at 2123 K, losing 10% of its weight in two minutes. Long term material tests on candidate materials for closed cycle helium cooled particle bed fuel elements are also described. Surface imperfections were found on the surface of pyrocarbon-coated fuel particles after ninety days exposure to flowing (approx.500 ppM) impure helium at 1143 K. The imperfections were superficial and did not affect particle strength.
Date: 1987~
Creator: Horn, F. L.; Powell, J. R. & Wales, D.
System: The UNT Digital Library
Preparation of radioactive ''mixed'' waste samples for measurement of RCRA (Resource Conservation and Recovery Act) organic compounds. [Mixed waste containing alpha-, beta-, or gamma-emitting radionuclides] (open access)

Preparation of radioactive ''mixed'' waste samples for measurement of RCRA (Resource Conservation and Recovery Act) organic compounds. [Mixed waste containing alpha-, beta-, or gamma-emitting radionuclides]

A radioactive ''mixed'' waste typically contains alpha-, beta-, or gamma-emitting radionuclides and varying quantities of semivolatile or volatile organic species, some or all of which may be named specifically by the Resource Conservation and Recovery Act (RCRA). Because there are no acceptable means available currently for disposing of these mixed wastes, they are presently stored above-ground in sealed drums. For this reason, analytical procedures which can determine RCRA organics in radioactive waste are necessary for deciding the proper approach for disposal. An important goal of this work is the development of methods for preparing mixed waste samples in a manner which allows the RCRA organics to be measured in conventional organic analysis laboratories without special precautions. Analytical procedures developed for handling mixed waste samples must satisfy not only the usual constraints present in any trace-level organic chemical determination, but also those needed to insure the protection of the operator from radioactive contamination. Consequently, procedures should be designed to use the least amount of radioactive sample commensurate with achieving acceptable sensitivity with the RCRA analytical methods. Furthermore, the unusual laboratory glassware which would normally be used should be replaced with disposable materials wherever possible, in order to reduce the ''clean-up'' time …
Date: January 1, 1987
Creator: Tomkins, Bruce A. & Caton, John E.
System: The UNT Digital Library
Sources of data in the GenBank database (open access)

Sources of data in the GenBank database

The citations in GenBank are characterized with respect to form of publication. The potential spectrum of quality control problems applicable to the various types of unpublished data are discussed. 6 refs., 2 tabs.
Date: January 1, 1987
Creator: Burks, C.
System: The UNT Digital Library
Using the NeWS window system in a Cray environment (open access)

Using the NeWS window system in a Cray environment

NeWS is structured as a single UNIX process, a network server that contains a PostScript interpreter. Client programs, which exist somewhere out on the network, talk to NeWS through byte streams. This paper describes the implementation of such a client interface on a Cray running the UNICOS operating system. With only a modest effort, it is possible to fit a simple PostScript interface to existing mainframe applications, which allows the user to graphically interact with the program from a remote workstation. Some typical applications, which have been structured as NeWS clients, have been described.
Date: June 1, 1987
Creator: Phillips, R.L. & Forslund, D.W.
System: The UNT Digital Library
Fuel cells for extraterrestrial and terrestrial applications (open access)

Fuel cells for extraterrestrial and terrestrial applications

The fuel cell is a nineteenth century invention and a twentieth century technology development. Due to the high power and energy density, high efficiency, reliability, and production of pure water, hydrogen-oxygen fuel cell systems have no competition as auxiliary power sources for space vehicles. The alkaline fuel cell system is a well developed and proven technology for this application. The solid polymer electrolyte system may be its future competitor. The energy crisis of 1973 stimulated research, development and demonstration of the phosphoric acid, molten carbonate, solid oxide and solid polymer electrolyte fuel cell systems using natural gas, petroleum or coal derived hydrogen (and carbon monoxide for the high temperature systems) for terrestrial applications. The direct methanol-air fuel cell is still an electrochemist's dream. Though considerable technological advances have been made, the present price of crude oil, and the high capital costs and limited lifetime of fuel cell systems impede their terrestrial applications in the developed countries. Conversely, the potential for lower capital costs of labor intensive manufacturing processes and the relatively higher fossil fuel prices make these systems more attractive for such applications in the developing countries. 11 refs.
Date: January 1, 1987
Creator: Srinivasan, S.
System: The UNT Digital Library
Inflation in the Universe (open access)

Inflation in the Universe

The hot big bang cosmology, or the standard cosmology as it is appropriately known, is a highly successful model, providing a reliable and tested accounting of the Universe from 0.01 sec after the bang until today, some 15 Gyr later. However, very special initial data seem to be required in order to account for the observed smoothness and flatness of our Hubble volume and for the existence of the small primeval density inhomogeneities required for the formation of structure in the Universe. Inflation offers a means of accounting for these special initial data, which is based upon physics at sub-planck energy scales (<< m/sub pl/ approx. = 10/sup 19/ GeV) and is motivated by contemporary ideas in particle theory. Here I review the status of the 'Inflationary Paradigm'. At present essentially all inflationary models involve a very weakly-coupled (quantified by the presence of a dimensionless parameter of order 10/sup -12/ or so) scalar field which is displaced from the minimum of its potential. Regions of the Universe where the scalar field is initially displaced from its minimum undergo inflation as the scalar field relaxes, resulting in a Universe today which resembles ours in regions much larger than our present Hubble …
Date: May 1, 1987
Creator: Turner, M. S.
System: The UNT Digital Library
Ti-6%Al-4%V alloy wave profile measurements in the shadow region (open access)

Ti-6%Al-4%V alloy wave profile measurements in the shadow region

VISAR wave profile measurements were made on the Ti-6%Al-4%V alloy to elucidate why the Hugoniot does not extrapolate through the bulk sound speed at zero pressure. Symmetric impact experiments were performed on targets with LiF windows in the shadow region (P < 40 GPa). Large elastic waves (2.8 GPa) were observed that appeared to shock-up. The low pressure Hugoniot is given by /sup l/U/sub s/ = 5.123 km/s + 1.083 U/sub p/ for U/sub p/ < 1.4 km/s. No phase transformations were observed in this region.
Date: January 1, 1987
Creator: Morris, C.E.; Winkler, M.A. & Mitchell, A.C.
System: The UNT Digital Library
Hydraulic and mechanical properties of natural fractures in low-permeability rock (open access)

Hydraulic and mechanical properties of natural fractures in low-permeability rock

The results of a comprehensive laboratory study of the mechanical displacement, permeability, and void geometry of single rock fractures in a quartz monzonite are summarized and analyzed. A metal-injection technique was developed that provided quantitative data on the precise geometry of the void spaces between the fracture surfaces and the areas of contact at different stresses. At effective stresses of less than 20 MPa fluid flow was proportional to the mean fracture aperture raised to a power greater than 3. As stress was increased, contact area was increased and void spaces become interconnected by small tortuous channels that constitute the principal impediment to fluid flow. At effective stresses higher than 20 MPa, the mean fracture aperture continued to diminish with increasing stress, but this had little effect on flow because the small tortuous flow channels deformed little with increasing stress.
Date: January 1, 1987
Creator: Pyrack-Nolte, L.J.; Myer, L.R.; Cook, N.G.W. & Witherspoon, P.A.
System: The UNT Digital Library
Development of the Be(d,n) neutron source for cross-section investigations in the few-MeV energy range (open access)

Development of the Be(d,n) neutron source for cross-section investigations in the few-MeV energy range

Bombardment of thick Be-metal targets with several-MeV deuterons produces continuum-neutron fields which offer considerable potential for the development and validation of neutron-reaction cross sections. A facility based on this concept has been installed at the Argonne National Laboratory FNG accelerator. A description is provided of this facility and of the research studies which have been initiated to exploit its capabilities. Some technical considerations in the utilization of accelerator-produced continuum-neutron fields for reaction cross-section investigations are discussed. Results from several recent neutron-spectrum and integral cross-section measurements are presented, and the implications are reviewed. 13 refs., 8 figs.
Date: May 1, 1987
Creator: Smith, D. L.; Meadows, J. W.; Guenther, P. T. & Greenwood, L. R.
System: The UNT Digital Library
Proceedings of the Fast Burst Reactor Workshop held in Albuquerque, NM, April 8 - 10, 1986 (open access)

Proceedings of the Fast Burst Reactor Workshop held in Albuquerque, NM, April 8 - 10, 1986

Separate abstracts were prepared for the individual papers of this report. (JDB)
Date: February 1, 1987
Creator: Luera, T.F.
System: The UNT Digital Library
Materials used in low-level liquid waste reprocessing/treatment studies at Oak Ridge National Laboratory (open access)

Materials used in low-level liquid waste reprocessing/treatment studies at Oak Ridge National Laboratory

The importance of effective waste management in the nuclear fuel cycle cannot be overestimated. At Oak Ridge National Laboratory (ORNL), development work in waste reprocessing and treatment includes the testing and use of various additives for the purpose of facilitating adherence to both process and regulatory performance criteria. Three waste reprocessing/treatment technologies and the associated materials are discussed in this paper: (1) suspension and transfer of sludge from waste storage tanks; (2) treatment to render a waste in compliance with regulatory requirements; and (3) fluoride-rich waste reprocessing. 7 refs., 3 figs.
Date: January 1, 1987
Creator: McDaniel, E. W.; Weeren, H. O.; Delzer, D. B.; Sams, T. L. & Tallent, O. K.
System: The UNT Digital Library
Ultra-high temperature direct propulsion (open access)

Ultra-high temperature direct propulsion

Potential advantages of ultra-high exhaust temperature (3000 K - 4000 K) direct propulsion nuclear rockets are explored. Modifications to the Particle Bed Reactor (PBR) to achieve these temperatures are described. Benefits of ultra-high temperature propulsion are discussed for two missions - orbit transfer (..delta..V = 5546 m/s) and interplanetary exploration (..delta..V = 20000 m/s). For such missions ultra-high temperatures appear to be worth the additional complexity. Thrust levels are reduced substantially for a given power level, due to the higher enthalpy caused by partial disassociation of the hydrogen propellant. Though technically challenging, it appears potentially feasible to achieve such ultra high temperatures using the PBR.
Date: January 1, 1987
Creator: Araj, K. J.; Slovik, G.; Powell, J. R. & Ludewig, H.
System: The UNT Digital Library
The Light Ion Biomedical Research Accelerator (LIBRA) (open access)

The Light Ion Biomedical Research Accelerator (LIBRA)

LIBRA is a concept to place a light-ion, charged-particle facility in a hospital environment, and to dedicate it to applications in biology and medicine. There are two aspects of the program envisaged for LIBRA: a basic research effort coupled with a program in clinical applications of accelerated charged particles. The operational environment to be provided for LIBRA is one in which both of these components can coexist and flourish, and one that will promote the transfer of technology and knowledge from one to the other. In order to further investigate the prospects for a Light Ion Biomedical Research Accelerator (LIBRA), discussions are underway with the Merritt Peralta Medical Center (MPMC) in Oakland, California, and the University of California at San Francisco (UCSF). In this paper, a brief discussion of the technical requirements for such a facility is given, together with an outline of the accelerator technology required. While still in a preliminary stage, it is possible nevertheless to develop an adequate working description of the type, size, performance and cost of the accelerator facilities required to meet the preliminary goals for LIBRA.
Date: March 1, 1987
Creator: Gough, R.A.
System: The UNT Digital Library
Adiabatic supernova expansion into the circumstellar medium (open access)

Adiabatic supernova expansion into the circumstellar medium

We perform one dimensional numerical simulations with a Lagrangian hydrodynamics code of the adiabatic expansion of a supernova into the surrounding medium. The early expansion follows Chevalier's analytic self-similar solution until the reverse shock reaches the ejecta core. We follow the expansion as it evolves towards the adiabatic blast wave phase. Some memory of the earlier phases of expansion is retained in the interior even when the outer regions expand as a blast wave. We find the results are sensitive to the initial configuration of the ejecta and to the placement of gridpoints. 6 refs., 2 figs.
Date: June 8, 1987
Creator: Band, D.L. & Liang, E.P.
System: The UNT Digital Library