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18,841 Matching Results
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Particle identification in ultrarelativistic nuclear collisions
The role of particle identification (PID) in both fixed-target and colliding-beam studies of ultrarelativistic nuclear (URN) collisions is examined. The demands placed on the PID systems by peculiarities of URN collisions, such as large multiplicities and the need for simultaneous measurement of a number of observables, are discussed. A variety of PID techniques are reviewed, with emphasis on their applicability and efficiency in the environment of such collisions. Two examples of PID as incorporated into existing fixed-target nuclear-beam experiments are presented. 18 refs., 5 figs.
Date:
April 1, 1986
Creator:
DiGiacomo, N.J.
Object Type:
Article
System:
The UNT Digital Library
Two exercises in supersymmetry: a low-energy supergravity model and free string field theory
The new features of a supersymmetric standard model in the presence of heavy families are studied. The minimal set of Higgs fields, the desert between the electroweak and the grand unification scale and perturbative values of the dimensionless parameters throughout this region are assumed. Using the numerical as well as the approximate analytic solution of the renormalization group equations, the evolution of all the parameters of the theory are studied in the case of large Yukawa couplings for the fourth family. The desired spontaneous symmetry breaking of the electroweak symmetry takes place only for a rather unnatural choice of the initial values of certain mass parameters at the grand unification scale. If it is gravitino mass smaller than 200 GeV the vacuum expectation values of the Higgs fields emerge necessarily in an interplay of the tree level Higgs potential and its quantum corrections and are approximately equal. The qurak masses of the fourth family are roughly 135 GeV, while the mass of the fourth charged lepton has an upper bound of 90 GeV. Further characteristic features of this scenario are one light neutral Higgs field of mass 50 GeV and gluino masses below 75 GeV. If the gravitino mass is …
Date:
September 1, 1986
Creator:
Preitschopf, C.R.
Object Type:
Report
System:
The UNT Digital Library
Proceedings of the LAMPF workshop on physics with polarized nuclear targets
Topics of discussion included static and dynamic methods for polarizing nuclei, proton and pion nucleus scattering experiments, and possible future experiments at LAMPF. Separate abstracts were prepared for 11 papers in this report. (DWL)
Date:
August 1, 1986
Creator:
Burleson, G.; Gibbs, W.; Hoffmann, G.; Jarmer, J. J. & Tanaka, N. (eds.)
Object Type:
Article
System:
The UNT Digital Library
Analysis of the results of the Midland PRA
This paper presents the results of a limited review of the Midland PRA (MPRA), aimed at facilitating regulatory analyses and at providing insights into safety related plant failures. In particular, stress was laid on the root causes of accident sequences, particularly their failure modes, viz., hardware, human, maintenance, test, and repair. Because this information was difficult to extract in this detailed and sophisticated PRA (and in certain others) a special algorithm was developed to display the leading sequences contributing to core damage and/or to public risk in terms of the above generic failure modes. This was done in a hierarchical fashion to allow tracing the important accident sequences to the systems failures. The weighted core damage frequency (CDF) values of the sequences considered then provided a (quantitative) ranked importance listing of these failure modes, led by hardware failures (in 78%) and human factors (in 37%), etc. Multiple maintenance situations (reflecting on test and maintenance specifications) were also evaluated, but played only a small role (less than or equal to3%). Similar tabulations were also made of the (weighted) importance of the support systems (such as the electric power system, the component cooling water systems, etc.) and of the role of the …
Date:
January 1, 1986
Creator:
Bozoki, G. & Teichmann, T.
Object Type:
Article
System:
The UNT Digital Library
Use of molybdenum ion source electrodes at RTNS-II
Reports are reported for an ongoing effort to optimize D+ beam production by the MATS-III ion source used at RTNS-II. The three seven-aperture electrodes, originally consisting of water-cooled copper, have now been tested using uncooled molybdenum and with water cooling on the second (decel) electrode only. Details of the change, the results of the testing, and the benefits in operation, performance and cost are given.
Date:
September 29, 1986
Creator:
Massoletti, D.J.; Harter, G.A. & Heikkinen, D.W.
Object Type:
Article
System:
The UNT Digital Library
Manipulator comparative testing program
The Manipulator Comparative Testing Program examined differences among manipulator systems from the United States and Japan. The manipulator systems included the Meidensha BILARM 83A, the Model M-2 of Central Research Laboratories Division of Sargent Industries (CRL), and the GCA Corporation PaR Systems Model 6000. The site of testing was the Remote Operations Maintenance Demonstration (ROMD) facility, operated by the Fuel Recycle Division in the Consolidated Fuel Reprocessing Program at the Oak Ridge National Laboratory (ORNL). In all stages of testing, operators using the CRL Model M-2 manipulator had consistently lower times to completion and error rates than they did using other machines. Performance was second best with the Meidensha BILARM 83A in master-slave mode. Performance with the BILARM in switchbox mode and the PaR 6000 manipulator was approximately equivalent in terms of criteria recorded in testing. These data show no impact of force reflection on task performance.
Date:
January 1, 1986
Creator:
Draper, J. V.; Handel, S. J.; Sundstrom, E.; Herndon, J. N.; Fujita, Y. & Maeda, M.
Object Type:
Article
System:
The UNT Digital Library
Construction and testing of the Mirror Fusion Test Facility magnets
This paper describes the construction and testing of the Mirror Fusion Test Facility superconducting magnet set. Construction of the first Yin Yang magnet was started in 1978. And although this particular magnet was later modified, the final construction of these magnets was not completed until 1985. When completed these 42 magnets weighed over 1200 tonnes and had a maximum stored energy of approximately 1200 MJ at full field. Together with power supplies, controls and liquid nitrogen radiation shields the cost of the fabrication of this system was over $100M. General Dynamics/Convair Division was responsible for the system design and the fabrication of 20 of the magnets. This contract was the largest single procurement action at the Lawrence Livermore National Laboratory. During the PACE acceptance tests, the 26 major magnets were operated at full field for more than 24 hours while other MFTF subsystems were tested. From all of the data, the magnets operated to the performance specifications. For physics operation in the future, additional helium and nitrogen leak checking and repair will be necessary. In this report we will discuss the operation and testing of the MFTF Magnet System, the world's largest superconducting magnet set built to date. The topics …
Date:
August 1, 1986
Creator:
Kozman, T.; Shimer, D.; VanSant, J. & Zbasnik, J.
Object Type:
Article
System:
The UNT Digital Library
Physics of antimatter-matter reactions for interstellar propulsion
At the stage of the antiproton-nucleon annihilation chain of events relevant to propulsion the annihilation produces energetic charged pions and gamma rays. If annihilation occurs in a complex nucleus, protons, neutrons, and other nuclear fragments are also produced. The charge, number, and energy of the annihilation products are such that annihilation rocket engine concepts involving relatively low specific impulse (I/sub sp/ approx. = 1000 to 2000 s) and very high I/sub sp/ (3 x 10/sup 7/ s) appear feasible and have efficiencies on the order of 50% for annihilation energy to propulsion energy conversion. At I/sub sp/'s of around 15,000 s, however, it may be that only the kinetic energy of the charged nuclear fragments can be utilized for propulsion in engines of ordinary size. An estimate of this kinetic energy was made from known pieces of experimental and theoretical information. Its value is about 10% of the annihilation energy. Control over the mean penetration depth of protons into matter prior to annihilation is necessary so that annihilation occurs in the proper region within the engine. Control is possible by varying the antiproton kinetic energy to obtain a suitable annihilation cross section. The annihilation cross section at low energies is …
Date:
August 22, 1986
Creator:
Morgan, D.L. Jr.
Object Type:
Article
System:
The UNT Digital Library
Magnetic measurements of the transuranium elements. Progress report, January 1-December 31, 1986
Magnetic measurements have been made on polycrystalline CfCl/sub 3/ in both a hexagonal and orthorhombic crystal form. The magnetic properties were studied as a function of crystal structure by converting the same sample back and forth from one form to the other. In a continuation of a study of the magnetic transition temperature as a function of actinide-actinide separation of the curium pnictide series we have undertaken magnetic measurements on curium bismuthide during this contract period. We have accomplished several milestones in our program to grow single crystals of actinide metals and compounds and determine their solid-state properties. Previous physical property measurements on transamericium actinide materials have been mainly limited to polycrystalline samples due to the limited availability of materials and the great material losses incurred during the common crystal growth methods. We have investigated a low-loss, microscale technique of crystal growth using lanthanides as non-radioactive stand-ins for the radioactive actinides.
Date:
September 1, 1986
Creator:
Nave, S.E.
Object Type:
Report
System:
The UNT Digital Library
In-Vitro and in-Vivo Characterization of Ruthenium-Bleomycin Compared to Cobalt- and Copper-Bleomycin
Bleomycin (BLM) has undergone extensive investigation both as a cancer chemotherapeutic agent, and as a carrier for radionuclides for tumor imaging. The available methods or the radionuclides used, however, have had limited effectiveness. Although labeling of BLM with /sup 103/Ru has been reported earlier, we carried out a study to develop a more reproducible method of labeling particularly for use with Brookhaven Linac Isotope Producer produced /sup 97/Ru. Ruthenium-97 has favorable physical properties that make it ideal for imaging applications: decay by electron capture; ..gamma.. 216 keV, 85%; t/sub 1/2/ 2.9 d. A novel method based on the reduction of Ru/sup 3 +/ to Ru/sup 2 +/ using stannous chloride was investigated for labeling BLM with /sup 97/Ru and/or /sup 103/Ru. In-vitro and in vivo comparisons of the product(s) with /sup 57/Co and /sup 67/Cu-labeled BLM were also carried out. 4 refs., 3 tabs.
Date:
January 1, 1986
Creator:
Shao, H. S.; Meinken, G. E.; Srivastava, S. C.; Slosman, D.; Sacker, D. F.; Som, P. et al.
Object Type:
Article
System:
The UNT Digital Library
Radiation-induced segregation in HT-9 martensitic steel
Miniature notched-bar specimens of normalized and tempered HT-9 were neutron irradiated to approx.13 dpa and broken at liquid nitrogen temperatures in a UHV chamber. Fracture surfaces were analyzed using scanning Auger electron spectroscopy. Following irradiation at 410/sup 0/C, the fracture surface contained a small number of large relatively smooth facets, which are thought to be prior austenite grain boundaries. Strong segregation of Ni, Cr, Si, and P was detected at these surfaces, the remainder of the fracture surface showing no evidence of segregation. At irradiation temperatures of 520/sup 0/ and 565/sup 0/C, there was relatively little segregation and none was found in thermal controls.
Date:
January 1, 1986
Creator:
Clausing, R.E.; Heatherly, L.; Faulkner, R.G.; Rowcliffe, A.F. & Farrell, K.
Object Type:
Article
System:
The UNT Digital Library
Habitat Evaluation and Monitoring in the Columbia River Basin, Final Report.
The law established the Northwest Power Planning Council to prepare and adopt a regional conservation and electric power plan, and a program to protect, mitigate, and enhance fish and wildlife. The objectives are the development of regional plans and programs related to energy conservation, renewable resources, other resources, and protecting mitigating, and enhancing fish and wildlife resources and to protect, mitigate, and enhance the fish and wildlife, including related spawning grounds and habitat, of the Columbia River and its tributaries. 4 refs.
Date:
December 1, 1986
Creator:
Everson, Larry B.; Campbell, Charles J.; Craven, Richard E. & Welsh, Thomas L.
Object Type:
Report
System:
The UNT Digital Library
Calculation of three-dimensional MHD equilibria with islands and stochastic regions
A three-dimensional MHD equilibrium code is described that does not assume the existence of good surfaces. Given an initial guess for the magnetic field, the code proceeds by calculating the pressure-driven current and then by updating the field using Ampere's law. The numerical algorithm to solve the magnetic differential equation for the pressure-driven current is described, and demonstrated for model fields having islands and stochastic regions. The numerical algorithm which solves Ampere's law in three dimensions is also described. Finally, the convergence of the code is illustrated for a particular stellarator equilibrium with no large islands.
Date:
August 1, 1986
Creator:
Reiman, A. & Greenside, H.
Object Type:
Report
System:
The UNT Digital Library
Insights from an overview of four PRAs
This paper summarizes the findings of an investigation of four probabilistic risk assessments (PRAs), those for Millstone 3, Seabrook, Shoreham, and Oconee 3, performed by Brookhaven National Laboratory (BNL) for the Reliability and Risk Assessment Branch of the US Nuclear Regulatory Commission (NRC). This group of four PRAs was subjected to an overview process with the basic goal of ascertaining what insights might be gained (beyond those already documented within the individual PRAs) by an independent evaluation of the group with respect to nuclear plant safety and vulnerability. Specifically, the objectives of the study were (1) to identify and rank initiators, systems, components, and failure modes from dominant accident sequences according to their contribution to core melt probability and public risk; and (2) to derive from this process plant-specific and generic insights. The effort was not intended to verify the specific details and results of each PRA but rather - having accepted the results - to see what they might mean in a more global context. The NRC had previously sponsored full detailed reviews of each of these PRAs, but only two, those for Millstone 3 and Shoreham, were completed and documented in time to allow their consideration within the …
Date:
January 1, 1986
Creator:
Fitzpatrick, R.; Arrieta, L.; Teichmann, T. & Davis, P.
Object Type:
Article
System:
The UNT Digital Library
Control room habitability study: findings and recommendations
The Advisory Committee on Reactor Safeguards (ACRS) has raised a number of concerns related to control room habitability and has recommended actions which they believe could alleviate these concerns. As a result of the ACRS's concerns, the US Nuclear Regulatory Commission's (NRC) Office of Nuclear Reactor Regulation (NRR) in conjunction with the Offices of Research and Inspection and Enforcement, and the NRC regional offices, embarked upon a program to reevaluate Control Room Habitability. Argonne National Laboratory was contracted by the NRC to perform a Control Room Habitability Study on twelve licensed power reactors. The plants selected for the study were chosen based upon architect engineer, nuclear steam system supplier, utility, and plant location. Participants in the study review the plant design as contained in the Updated Safety Analysis Report, Technical Specifications, Three Mile Island action item III.D.3.4 submittal on Control Room Habitability, NRC staff evaluation of the III.D.3.4 submittal, appropriate plant operating procedures, system drawings, and significant Licensee Event Reports on Loss of Cooling to the Control Room Envelope. A two-day visit is then made to the plant to determine if the as-built systems are built, operated, and surveillance performed as described in the documentation reviewed prior to the visit. …
Date:
January 1, 1986
Creator:
Driscoll, J.W.
Object Type:
Article
System:
The UNT Digital Library
Massive sulfide deposits and hydrothermal solutions: incremental reaction modeling of mineral precipitation and sulfur isotopic evolution
Incremental reaction path modeling of chemical and sulfur isotopic reactions occurring in active hydrothermal vents on the seafloor, in combination with chemical and petrographic data from sulfide samples from the seafloor and massive sulfide ore deposits, allows a detailed examination of the processes involved. This paper presents theoretical models of reactions of two types: (1) adiabatic mixing between hydrothermal solution and seawater, and (2) reaction of hydrothermal solution with sulfide deposit materials. In addition, reaction of hydrothermal solution with sulfide deposit minerals and basalt in feeder zones is discussed.
Date:
January 1, 1986
Creator:
Janecky, D.R.
Object Type:
Article
System:
The UNT Digital Library
Nuclear alkali metal Rankine power systems for space applications
Nucler power systems utilizing alkali metal Rankine power conversion cycles offer the potential for high efficiency, lightweight space power plants. Conceptual design studies are being carried out for both direct and indirect cycle systems for steady state space power applications. A computational model has been developed for calculating the performance, size, and weight of these systems over a wide range of design parameters. The model is described briefly and results from parametric design studies, with descriptions of typical point designs, are presented in this paper.
Date:
August 1, 1986
Creator:
Moyers, J. C. & Holcomb, R. S.
Object Type:
Article
System:
The UNT Digital Library
LFCM vitrification technology. Quarterly progress report, January-March 1986
This report is compiled by the Nuclear Waste Treatment Progrqam and the Hanford Waste Vitrification Program at Pacific Northwest Laboratory to document progress on liquid-fed ceramic melter (LFCM) vitrification technology. Progress in the following technical subject areas during the second quarter of FY 1986 is discussed: melting process chemistry and glass development, feed preparation and transfer systems, melter systems, canister filling and handling systems, off-gas systems, and process/product modeling and control.
Date:
September 1, 1986
Creator:
Burkholder, H. C. & Minor, J. E.
Object Type:
Report
System:
The UNT Digital Library
Feasibility of laser pumping with neutron fluxes from present-day large tokamaks
The minimum fusion-neutron flux needed to observe nuclear-pumped lasing with tokamaks can be reduced substantially by optimizing neutron scattering into the laser cell, located between adjacent toroidal-field coils. The laser lines most readily pumped are probably the /sup 3/He-Ne lines at 0.633 ..mu.. and in the infrared, where the /sup 3/He-Ne gas is excited by energetic ions produced in the /sup 3/He(n,p)T reaction. These lines are expected to lase at the levels of D-T neutron flux foreseen for the TFTR in 1989 (>>10/sup 12/ n/cm/sup 2//s), while amplification should be observable at the existing levels of D-D neutron flux (greater than or equal to 5 x 10/sup 9/ n/cm/sup 2//s). Lasing on the 1.73 ..mu.. and 2.63 ..mu.. transitions of Xe may be observable at the maximum expected levels of D-T neutron flux in TFTR enhanced by scattering.
Date:
August 1, 1986
Creator:
Jassby, D. L.
Object Type:
Report
System:
The UNT Digital Library
Quark deconfinement and high energy nuclear collisions
Statistical QCD predicts that with increasing density, strongly interacting matter will undergo a transition to a plasma of deconfined quarks and gluons. High energy heavy ion collisions are expected to permit experimental studies of this transition and of the predicted new state of matter. 22 refs., 6 figs.
Date:
July 1, 1986
Creator:
Satz, H.
Object Type:
Article
System:
The UNT Digital Library
Plutonium isotopic analysis of highly enriched mixed oxides
We investigated the analysis method used by the International Atomic Energy Agency (IAEA) to determine the plutonium isotopic composition of highly enriched mixed oxides (MOX). The IAEA currently uses the Cicero multichannel analyzer and the IAEAPU algorithm for its analysis. In our investigation the plutonium isotopic measurements were found to be good for PuO/sub 2/ powder or low-enriched MOX, but acceptable for highly enriched MOX in IAEA special nuclear material (SNM) accountability applications. The gamma-ray interferences from /sup 235/U resulted in underestimation of the isotopic composition of /sup 239/Pu and overestimation of all other plutonium isotopes. Samples with high /sup 240/Pu content were found to have significantly higher error in plutonium isotopic analyses of highly enriched MOX. Code modifications or use of calibration curves are necessary for plutonium isotopic analyses of highly enriched MOX in IAEA SNM accountability applications.
Date:
August 1, 1986
Creator:
Clement, S. D. & Augustson, R. H.
Object Type:
Report
System:
The UNT Digital Library
Advanced accelerator research at Argonne
A facility with which to experimentally measure methods of advanced acceleration is at the point of completion at Argonne National Laboratory. The new facility consists a system which produces pulse ''doublets'' of energetic electrons, pulse shaping hardware, a space for experimental apparatus, and a high resolution spectrometer. The leading 21 MeV pulse in a doublet can contain up to 15 nano-coulombs of charge and can be adjusted to be from 6 to over 100 pic-seconds in length. The trailing doublet pulse is at 15 MeV, contains about 10/sup 6/ electrons, and can be precisely positioned behind the first from 0 to more than 2000 pico-seconds. This second pulse serves as a probe of fields produced by the intense leading pulse. The initial experimental program includes studies of wake field effects in structures and in plasma. The high resolution of the spectrometer will also make possible measurements of the wakes of various components such as bellows, beam signal pickups, and vacuum connections. Commissioning of the facility is to begin in September, 1986. Tests using cavities and plasma are expected to begin soon thereafter.
Date:
January 1, 1986
Creator:
Konecny, R.; MacLachlan, J.; Norem, J.; Ruggiero, A.; Schoessow, P. & Simpson, J.
Object Type:
Article
System:
The UNT Digital Library
Multiple track Doppler-shift spectroscopy system for TFTR neutral beam injectors
A Doppler-shift spectroscopy system has been installed on the TFTR neutral beam injection system to measure species composition during both conditioning and injection pulses. Two intensified vidicon detectors and two spectrometers are utilized in a system capable of resolving data from up to twelve ion sources simultaneously. By imaging the light from six ion sources onto one detector, a cost-effective system has been achieved. Fiber optics are used to locate the diagnostic in an area remote from the hazards of the tokamak test cell allowing continuous access, and eliminating the need for radiation shielding of electronic components. Automatic hardware arming and interactive data analysis allow beam composition to be computed between tokamak shots for use in analyzing plasma heating experiments. Measurements have been made using lines of sight into both the neutralizer and the drift duct. Analysis of the data from the drift duct is both simpler and more accurate since only neutral particles are present in the beam at this location. Comparison of the data taken at these two locations reveals the presence of partially accelerated particles possessing an estimated 1/e half-angle divergence of 15/sup 0/ and accounting for up to 30% of the extracted power.
Date:
September 1, 1986
Creator:
Kamperschroer, J. H.; Kugel, H. W.; Reale, M. A.; Hayes, S. L.; Johnson, G. A.; Lowrance, J. L. et al.
Object Type:
Report
System:
The UNT Digital Library
RIMS diagnostics for laser desorption/laser ablation
Laser desorption mass spectrometry is a useful method for interrogating materials and events at or near surfaces. Laser desorption/ablation combined with Resonance Ionization Mass Spectrometry (RIMS) provides a powerful tool to obtain information on chemical composition and speciation and, in some cases, internal and translational energy distributions. The application of this technique to the interrogation of materials and interfaces is discussed for several systems, including the analysis of conventional analytical samples, and the study of optical damage events. 8 refs., 2 figs., 1 tab.
Date:
January 1, 1986
Creator:
Apel, E. C.; Nogar, N. S.; Miller, C. M. & Estler, R. C.
Object Type:
Article
System:
The UNT Digital Library