Pion production in relativistic collisions of nuclear drops (open access)

Pion production in relativistic collisions of nuclear drops

In a continuation of the long-standing effort of the nuclear physics community to model atomic nuclei as droplets of a specialized nuclear fluid, we have developed a hydrodynamic model for simulating the collisions of heavy nuclei at relativistic speeds. Our model couples ideal relativistic hydrodynamics with a new Monte Carlo treatment of dynamic pion production and tracking. The collective flow for low-energy (200 MeV/N) collisions predicted by this model compares favorably with results from earlier hydrodynamic calculations which used quite different numerical techniques. Our pion predictions at these lower energies appear to differ, however, from the experimental data on pion multiplicities. In this case of ultra-relativistic (200 GeV/N) collisions, our hydrodynamic model has produced baryonic matter distributions which are in reasonable agreement with recent experimental data. These results may shed some light on the sensitivity of relativistic collision data to the nuclear equation of state. 20 refs., 12 figs.
Date: September 1, 1988
Creator: Alonso, C. T.; Wilson, J. R.; McAbee, T. L. & Zingman, J. A.
Object Type: Article
System: The UNT Digital Library
Proceedings of the technical review on advances in geothermal reservoir technology---Research in progress (open access)

Proceedings of the technical review on advances in geothermal reservoir technology---Research in progress

This proceedings contains 20 technical papers and abstracts describing most of the research activities funded by the Department of Energy (DOE's) Geothermal Reservoir Technology Program, which is under the management of Marshall Reed. The meeting was organized in response to several requests made by geothermal industry representatives who wanted to learn more about technical details of the projects supported by the DOE program. Also, this gives them an opportunity to personally discuss research topics with colleagues in the national laboratories and universities.
Date: September 1, 1988
Creator: Lippmann, M.J. (ed.)
Object Type: Article
System: The UNT Digital Library
Beta-delayed proton emission in neutron-deficient lanthanide isotopes (open access)

Beta-delayed proton emission in neutron-deficient lanthanide isotopes

Forty-two ..beta..-delayed proton precursors with 56less than or equal toZless than or equal to71 and 63less than or equal toNless than or equal to83 were produced in heavy-ion reactions at the Lawrence Berkeley Laboratory SuperHILAC and their radioactive decay properties studied at the on-line mass separation facility OASIS. Twenty-five isotopes and eight delayed proton branches were identified for the first time. Delayed proton energy spectra and proton coincident ..gamma..-ray and x-ray spectra were measured for all precursors. In a few cases, proton branching ratios were also determined. The precursor mass numbers were determined by the separator, while the proton coincident x-ray energies provided unambiguous Z identifications. The proton coincident ..gamma..-ray intensities were used to extract final state branching ratios. Proton emission from ground and isomeric states was observed in many cases. The majority of the delayed proton spectra exhibited the smooth bell-shaped distribution expected for heavy mass precursors. The experimental results were compared to statistical model calculations using standard parameter sets. Calculations using Nilsson model/RPA ..beta..-strength functions were found to reproduce the spectral shapes and branching ratios better than calculations using either constant or gross theory ..beta..-strength functions. Precursor half-life predictions from the Nilsson model/RPA ..beta..-strength functions were also in …
Date: September 30, 1988
Creator: Wilmarth, P.A.
Object Type: Report
System: The UNT Digital Library
Shielding effectiveness of superconductive particles in plastics (open access)

Shielding effectiveness of superconductive particles in plastics

The ability to cool superconductors with liquid nitrogen instead of liquid helium has opened the door to a wide range of research. The well known Meissner effect, which states superconductors are perfectly diamagnetic, suggests shielding applications. One of the drawbacks to the new ceramic superconductors is the brittleness of the finished material. Because of this drawback, any application which required flexibility (e.g., wire and cable) would be impractical. Therefore, this paper presents the results of a preliminary investigation into the shielding effectiveness of YBa/sub 2/Cu/sub 3/O/sub 7-x/ both as a composite and as a monolithic material. Shielding effectiveness was measured using two separate test methods. One tested the magnetic (near field) shielding, and the other tested the electromagnetic (far field) shielding. No shielding was seen in the near field measurements on the composite samples, and only one heavily loaded sample showed some shielding in the far field. The monolithic samples showed a large amount of magnetic shielding. 5 refs., 5 figs.
Date: September 1, 1988
Creator: Pienkowski, T.; Kincaid, J.; Lanagan, M.T.; Poeppel, R.B.; Dusek, J.T.; Shi, D. et al.
Object Type: Article
System: The UNT Digital Library
PEGASYS: A proposed internal target-spectrometer facility for the PEP storage ring (open access)

PEGASYS: A proposed internal target-spectrometer facility for the PEP storage ring

A proposal for an internal gas-jet target and forward spectrometer for the PEP storage ring is described. The beam structure, allowable luminosity (L=10/sup 33/ cm/sup /minus/2/s/sup /minus/1/ for H/sub 2/, D/sub 2/ decreasing as Z/sup /minus/1.75/ for nuclear targets) and energy (E/sub e/less than or equal to 15 GeV) make the ring ideal for multiparticle coincidence studies in the scaling regime, and where perturbative QCD may be an apt description of some exclusive and semi-inclusive reactions. 17 refs., 5 figs.
Date: September 1, 1988
Creator: Van Bibber, K.
Object Type: Article
System: The UNT Digital Library
Magnet systems for the International Thermonuclear Experimental Reactor (open access)

Magnet systems for the International Thermonuclear Experimental Reactor

The definition phase for the International Thermonuclear Experimental Reactor (ITER) has been nearly completed, thus beginning a three-year design effort by teams from the European Community (EC), Japan, US, and USSR. Preliminary parameters for the superconducting magnet system have been established to guide more detailed design work. Radiation tolerance of the superconductors and insulators has been important because it sets requirements for the neutron-shield dimension and sensitively influences reactor size. Major levels of mechanical stress appear in the structural cases of the inboard legs of the toroidal-field (TF) coils. The winding packs of the TF coils include significant fractions of steel that provide support against in-plane separating loads, but they offer little support against out-of-plane loads unless shear-bonding of the conductors can be maintained. Heat removal from nuclear and ac loads has not limited the fundamental design, but it has nonnegligible economic consequences. 3 refs., 3 figs., 5 tabs.
Date: September 22, 1988
Creator: Henning, C. D. & Miller, J. R.
Object Type: Article
System: The UNT Digital Library
The Canadian experimental HT release of June 10, 1987, US measurements (open access)

The Canadian experimental HT release of June 10, 1987, US measurements

In June 1987, an experiment was performed at the Chalk River Nuclear Laboratories in Ontario, Canada, to study the oxidation of elemental tritium (HT) released to the environment. The experiment involved a 30-minute release of 3.54 TBq (95.7 Ci)of HT to the atmosphere at an elevation of one meter. Scientists from six countries participated in the experiment. The air measurements showed HT concentrations downwind of the release in general agreement with classical atmospheric diffusion (Gaussian) up to the maximum distance measured (400 m). The HTO/HT ratios were shown to slowly increase downwind (approx. 4 x 10/sup /minus/5/ at 50 m to almost 10/sup /minus/3/ at 400 m) as conversion of HT took place. After the release, HTO concentrations in the atmosphere remained elevated. Vegetation samples were also taken since the vegetation and associated soil system have been implicated in the oxidation of HT. Freeze-dried water from vegetation samples was found to be low in HTO immediately after the release suggesting a low direct uptake of HTO in air by vegetation. The tritiated water concentration increased during the first day, peaking during the second day (about 15--30 kBq/L of water at 50 m from the source), and decreasing by the end …
Date: September 1, 1988
Creator: Jalbert, R. A. & Murphy, C. E.
Object Type: Report
System: The UNT Digital Library
The Environmental Effects of Nuclear War (open access)

The Environmental Effects of Nuclear War

Substantial environmental disruption will significantly add to the disastrous consequences caused by the direct thermal, blast, and radiological effects brought on by a major nuclear war. Local fallout could cover several percent of the Northern Hemisphere with potentially lethal doses. Smoke from post-nuclear fires could darken the skies and induce temperature decreases of tens of degrees in continental interiors. Stratospheric ozone could be significantly reduced due to nitric oxide injections and smoke-induced circulation changes. The environmental effects spread the consequences of a nuclear war to the world population, adding to the potentially large disruptive effects a further reason to avoid such a catastrophe. 27 refs., 4 figs.
Date: September 1, 1988
Creator: MacCracken, Michael C.
Object Type: Article
System: The UNT Digital Library
The Public Utilities Regulatory Policy Act (PURPA) and US Geothermal Industry: Current controversies and trends in federal and state implementation (open access)

The Public Utilities Regulatory Policy Act (PURPA) and US Geothermal Industry: Current controversies and trends in federal and state implementation

This report is an analysis of the issues confronting US energy policymakers and the US geothermal industry as the result of the implementation and interpretation of the 1978 Public Utility Regulatory Policies Act, commonly known as PURPA. It seeks to answer four sets of questions about PURPA: (1) What has the existence of PURPA meant to the US geothermal industry. (2) How has the interpretation of PURPA evolved over the past decade. (3) What particular portions of PURPA rule making have been most crucial to the growth and development of the geothermal industry. (4) What aspects of PURPA have been most troubling to utilities purchasing or developing geothermal energy.
Date: September 1, 1988
Creator: unknown
Object Type: Report
System: The UNT Digital Library
(Dynamic interactions of charged particles) (open access)

(Dynamic interactions of charged particles)

The traveler worked with colleagues at San Sebastian on collaborative research projects, which have been conducted over an extended period of time, dealing with dynamic interactions of charged particles with condensed matter. While there, he participated in a Summer School in the Spectroscopy of Solid Surfaces and presented three invited lectures at the school. The traveler had extensive discussions with colleagues which led to new ideas for future research at ORNL. The indications for continued collaborative work look excellent.
Date: September 26, 1988
Creator: Ritchie, R. H.
Object Type: Report
System: The UNT Digital Library
EXODUS: A Finite Element File Format for Pre- and Postprocessing (open access)

EXODUS: A Finite Element File Format for Pre- and Postprocessing

The EXODUS format defines a binary file which is used for finite element analysis pre- and postprocessing. It includes data to define the finite element mesh and label both boundary condition and load application points. EXODUS accommodates multiple element types and is sufficiently general format for analysis results. A benefit of combining the mesh definition data and the results data in the same file is that the user is assured that the results data are consistent with the model. EXODUS is currently in use by the entire range of Department 1520 codes (including preprocessors, translators, linear and nonlinear analyses, and postprocessors) and is finding applications in codes outside Department 1520. 2 refs., 2 figs., 1 tab.
Date: September 1, 1988
Creator: Mills-Curran, William C.; Gilkey, Amy P. & Flanagan, Dennis P.
Object Type: Report
System: The UNT Digital Library
The Kalina cycle and similar cycles for geothermal power production (open access)

The Kalina cycle and similar cycles for geothermal power production

This report contains a brief discussion of the mechanics of the Kalina cycle and ideas to extend the concept to other somewhat different cycles. A modified cycle which has a potential heat rejection advantage but little or no performance improvement is discussed. Then, the results of the application of the Kalina cycle and the modified cycle to a geothermal application (360/degree/F resource) are discussed. The results are compared with published results for the Kalina cycle with high temperature sources and estimates about performance at the geothermal temperatures. Finally, the conclusions of this scoping work are given along with recommendations of the direction of future work in this area. 11 refs., 4 figs., 1 tab.
Date: September 1, 1988
Creator: Bliem, C.J.
Object Type: Report
System: The UNT Digital Library
A non-inductively driven steady state tokamak reactor (open access)

A non-inductively driven steady state tokamak reactor

The physics and engineering guidelines for the ITER device are shown to lead to viable and attractive operating points for a steady state tokamak power reactor. Non-inductive current drive is provided in steady state by high energy neutral beam injection in the plasma core, lower hybrid slow waves in the outer regions of the plasma and bootstrap current. Plasma gain Q (/equivalent to/fusion power/input power) in excess of 20 and average neutron wall loading, <GAMMA> approx. 2.0 MW/m/sup 2/ are predicted in a device with major radius, R/sub 0/ = 7.5 m and minor radius, a = 2.8 m. 15 refs., 3 figs., 3 tabs.
Date: September 20, 1988
Creator: Fenstermacher, M. E.; Devoto, R. S.; Bulmer, R. H.; Lee, J. D.; Miller, J. R. & Schultz, J.
Object Type: Article
System: The UNT Digital Library
Neutronics analysis of the Laboratory Microfusion Facility (open access)

Neutronics analysis of the Laboratory Microfusion Facility

The radiological safety hazards of the experimental area (EA) for the proposed Inertial Confinement Fusion (ICF) Laboratory Microfusion Facility (LMF) have been examined. The EA includes those structures required to establish the proper pre-shot environment, point the beams, contain the pellet yield, and measure many different facets of the experiments. The radiation dose rates from neutron activation of representative target chamber materials, the laser beam tubes and the argon gas they contain, the air surrounding the chamber, and the concrete walls of the experimental area are given. Combining these results with the allowable dose rates for workers, we show how radiological considerations affect access to the inside of the target chamber and to the diagnostic platform area located outside the chamber. Waste disposal and tritium containment issues are summarized. Other neutronics issues, such as radiation damage to the final optics and neutron heating of materials placed close to the target, are also addressed. 16 refs., 2 figs., 1 tab.
Date: September 19, 1988
Creator: Tobin, M. T.; Singh, M. S. & Meier, W. R.
Object Type: Article
System: The UNT Digital Library
DPDC (double-pass donor cell): A second-order monotone scheme for advection (open access)

DPDC (double-pass donor cell): A second-order monotone scheme for advection

We are developing a new, second-order, monotone scheme for advection. DPDC (i.e., double-pass donor cell) is based on Smolarkiewicz&#x27; simple, positive definite method. Both schemes are multipass methods in which upstream approximations to the truncation error are subtracted from the equations. We describe two significant improvements to Smolarkiewicz&#x27; method. First, we use a local gauge transformation to convert the method from being positive definite to the stronger condition of being monotone. Second, we analytically approximate the sum of the corrections of all the passes to use in a single corrective pass. This increases the accuracy of the method, but does not increase the order of accuracy. We compare DPDC with van Leer&#x27;s method for advection of several different pulses in a constant velocity field. 5 refs., 4 figs.
Date: September 26, 1988
Creator: Beason, C W & Margolin, L G
Object Type: Article
System: The UNT Digital Library
The Licensing Experience of the Modular High-Temperature Gas-Cooled Reactor (MHTGR) (open access)

The Licensing Experience of the Modular High-Temperature Gas-Cooled Reactor (MHTGR)

The MHTGR is an advanced reactor concept being developed under a cooperative program involving the US Government, the nuclear industry, and the utilities. The design utilizes the basic HTGR features of ceramic fuel, helium coolant, and a graphite moderator. However, the specific size and configuration are selected to utilize the inherent characteristics of these materials to develop passive safety features that provide a significantly higher margin of safety than current generation reactors. The design meets the US Environmental Protection Agency's Protective Action Guidelines at the site boundary, hence precluding the need for sheltering or vacation of the public during any licensing basis event. This safe behavior is not dependent upon operator action and is insensitive to operator error. The MHTGR Licensing Plan agreed to with the US Nuclear Regulatory Commission (NRC) is discussed with particular attention to the framework of the preapplication review. The objective and scope of each key document prepared for the NRC review is presented. A summary is provided of the safety response to events challenging the functions relied on to retain radionuclides within the coated fuel particles. The regulatory interaction process and results are discussed through the NRC staff, NRC contractor, and ACRS reviews. 11 refs., …
Date: September 1, 1988
Creator: Silady, F.A.; Cunliffe, J.C. & Walker, L.P.
Object Type: Article
System: The UNT Digital Library
Nuclear effects in J//psi/ and lepton-pair production (open access)

Nuclear effects in J//psi/ and lepton-pair production

High-energy processes in nuclear media provide important tests of quantum chromodynamics, since in principle one can use the nuclear environment to perturb and study the mechanisms involved in confinement and hadronization. In this talk several examples of nuclear effects in QCD will be discussed that affect the propagation and hadronization of quarks and gluons in nuclear matter. The issues include: possible signatures for quark-gluon plasma formation in heavy ion collisions, particularly J//psi/ production; hadronization due to jet coalescence; the limits of validity of QCD factorization formulae due to initial- and final-state interactions; formation zone physics; shadowing of the quark and gluon structure functions of nuclei; and color transparency in hard quasielastic reactions inside of nuclei. 29 refs., 4 figs.
Date: September 1, 1988
Creator: Brodsky, Stanley J.
Object Type: Article
System: The UNT Digital Library
Physics modeling support for the International Thermonuclear Experimental Reactor: Final report (open access)

Physics modeling support for the International Thermonuclear Experimental Reactor: Final report

There are two major sections to this report. The first section of the report is an executive summary of the work done this year. For each task, the major results are condensed for the reader's convenience. The major result of each memo, report or presentation is summarized briefly in this section. The second section of the report is a collection of appendices containing reports, memos, and presentations written this year. Here, the interested reader can investigate any topic discussed in the summary in more detail. The documentation is presented in chronological order, and we would like to note that the content of later documents may supercede that of earlier ones. The summaries are divided into sections, corresponding to the tasks outlined in the original proposal for the work. These sections are: MUMAK code development and application; Alfven wave stability problem; TETRA systems code development and application; lower hybrid heating and current drive; and advanced blanket modeling.
Date: September 30, 1988
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Nonlinear gyrokinetic Maxwell-Vlasov equations using magnetic coordinates (open access)

Nonlinear gyrokinetic Maxwell-Vlasov equations using magnetic coordinates

A gyrokinetic formalism using magnetic coordinates is used to derive self-consistent, nonlinear Maxwell-Vlasov equations that are suitable for particle simulation studies of finite-..beta.. tokamak microturbulence and its associated anomalous transport. The use of magnetic coordinates is an important feature of this work as it introduces the toroidal geometry naturally into our gyrokinetic formalism. The gyrokinetic formalism itself is based on the use of the Action-variational Lie perturbation method of Cary and Littlejohn, and preserves the Hamiltonian structure of the original Maxwell-Vlasov system. Previous nonlinear gyrokinetic sets of equations suitable for particle simulation analysis have considered either electrostatic and shear-Alfven perturbations in slab geometry, or electrostatic perturbations in toroidal geometry. In this present work, fully electromagnetic perturbations in toroidal geometry are considered. 26 refs.
Date: September 1, 1988
Creator: Brizard, A.
Object Type: Report
System: The UNT Digital Library
Report on full-scale horizontal cable tray fire tests, FY 1988 (open access)

Report on full-scale horizontal cable tray fire tests, FY 1988

In recent years, there has been much discussion throughout industry and various governmental and fire protection agencies relative to the flammability and fire propagation characteristics of electrical cables in open cable trays. It has been acknowledged that under actual fire conditions, in the presence of other combustibles, electrical cable insulation can contribute to combustible fire loading and toxicity of smoke generation. Considerable research has been conducted on vertical cable tray fire propagation, mostly under small scale laboratory conditions. In July 1987, the Fermi National Accelerator Laboratory initiated a program of full scale, horizontal cable tray fire tests, in the absence of other building combustible loading, to determine the flammability and rate of horizontal fire propagation in cable tray configurations and cable mixes typical of those existing in underground tunnel enclosures and support buildings at the Laboratory. The series of tests addressed the effects of ventilation rates and cable tray fill, fire fighting techniques, and effectiveness and value of automatic sprinklers, smoke detection and cable coating fire barriers in detecting, controlling or extinguishing a cable tray fire. This report includes a description of the series of fire tests completed in June 1988, as well as conclusions reached from the test results.
Date: September 1, 1988
Creator: Riches, W.M.
Object Type: Report
System: The UNT Digital Library
Aspects of e/sup +/e/sup/minus// physics at 1 TeV (open access)

Aspects of e/sup +/e/sup/minus// physics at 1 TeV

A summary of several recent studies of electroweak e/sup +/e/sup /minus// physics is provided. The significance of upcoming SLC/LEP measurements of Z and W properties is discussed, with special emphasis placed on radiative corrections and polarization. New electroweak physics at a proposed TeV e/sup +/e/sup /minus// collider is presented as a natural outgrowth of the SLC/LEP programs. Precise tests of the trilinear gauge boson vertex through W pair production, searching for the disturbance of perturbative unitarity by radiative corrections, and of the gauge structure of a Z', through polarized e/sup /minus// beams, are presented. 19 refs.
Date: September 1988
Creator: Kennedy, Dallas C.
Object Type: Article
System: The UNT Digital Library
In situ ion irradiation/implantation studies in the HVEM-Tandem Facility at Argonne National Laboratory (open access)

In situ ion irradiation/implantation studies in the HVEM-Tandem Facility at Argonne National Laboratory

The HVEM-Tandem User Facility at Argonne National Laboratory interfaces two ion accelerators, a 2 MV tandem accelerator and a 650 kV ion implanter, to a 1.2 MV high voltage electron microscope. This combination allows experiments involving simultaneous ion irradiation/ion implantation, electron irradiation and electron microscopy/electron diffraction to be performed. In addition the availability of a variety of microscope sample holders permits these as well as other types of in situ experiments to be performed at temperatures ranging from 10-1300 K, with the sample in a stressed state or with simultaneous determination of electrical resistivity of the specimen. This paper summarizes the details of the Facility which are relevant to simultaneous ion beam material modification and electron microscopy, presents several current applications and briefly describes the straightforward mechanism for potential users to access this US Department of Energy supported facility. 7 refs., 1 fig., 1 tab.
Date: September 1, 1988
Creator: Allen, C. W.; Funk, L. L.; Ryan, E. A. & Taylor, A.
Object Type: Article
System: The UNT Digital Library
Third order TRANSPORT with MAD (Methodical Accelerator Design) input (open access)

Third order TRANSPORT with MAD (Methodical Accelerator Design) input

This paper describes computer-aided design codes for particle accelerators. Among the topics discussed are: input beam description; parameters and algebraic expressions; the physical elements; beam lines; operations; and third-order transfer matrix. (LSP)
Date: September 20, 1988
Creator: Carey, D.C.
Object Type: Report
System: The UNT Digital Library
Thermal-hydraulic analysis of TFE verification test UFAC-1 (open access)

Thermal-hydraulic analysis of TFE verification test UFAC-1

The Experimental Breeder Reactor No. II (EBR-II) irradiation test Uninstrumented Fueled Accelerated (UFAC)-1 of seven encapsulated thermionic test pins was analyzed with the code COBRA-SFS. The model predicted coolant and material temperatures for three conditions of interest: steady state full power, response to the unlikely loss of flow transient, and decay heat cooling by forced down flow of argon. Modeling assumptions and a summary of results are included. 1 ref., 12 figs., 3 tabs.
Date: September 1, 1988
Creator: McWethy, L. M.; Pearce, K. L. & Rector, D. R.
Object Type: Report
System: The UNT Digital Library