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Development of superconductors for applications in high-field, high-current-density magnets for fusion research (open access)

Development of superconductors for applications in high-field, high-current-density magnets for fusion research

The development of large-bore, high-field magnets for fusion energy applications requires a system approach to both magnet and conductor design. At Lawrence Livermore National Laboratory (LLNL), the criteria used to choose superconductors include: strain tolerance, radiation tolerance, heat removal, stability, fabricability, and cost. We report on the performance of industrially produced, prototype, Ti-modified Nb/sub 3/Sn wires developed with LLNL support. Wire performance characteristics evaluated include critical current as a function of magnetic field, temperature, and applied strain. Tests were performed to determine how this performance translates to the performance of a cable-in-conduit conductor system using this wire. An alternative to Nb/sub 3/Sn superconductors is NbN, which is strain and radiation insensitive. We report preliminary efforts to produce multifilamentary NbN conductors by liquid-metal infiltration of NbN-coated, high-strength fibers. In addition, we discuss the fabrication of multifilamentary NbN conductors and their possible impact on magnet design.
Date: September 26, 1986
Creator: Summers, L. T. & Miller, J. R.
System: The UNT Digital Library
Atom-in-jellium models (open access)

Atom-in-jellium models

The author describes in this paper the atom-in-jellium calculations he has been doing over the last ten years. He tries to emphasize reasons for doing this sort of calculations and why he devised a model which is different in some respects from others.
Date: April 26, 1985
Creator: Liberman, D.A.
System: The UNT Digital Library
Interferometric measurements of multilayer and double shell inertial fusion targets (open access)

Interferometric measurements of multilayer and double shell inertial fusion targets

Optical interference microscopy plays an important role in the measurement of targets for inertial confinement fusion experiments. We describe how these techniques are applied to the measurement of thickness and refractive index of multilayer films on both flat substrates and microsphere targets. We also discuss procedures for manipulating and examining microsphere targets to measure defects and wall thickness variations anywhere on the target. Finally, we describe the use of optical interferometry to measure the individual components and final assembled structure of double-shell targets. The accuracy of these measurements is from 0.03 to 0.5 ..mu..m, depending on the specific application.
Date: August 26, 1980
Creator: Weinstein, B.W.; Weir, J.T. & Willenborg, D.L.
System: The UNT Digital Library
Use of molecular beams to support microspheres during plasma coating (open access)

Use of molecular beams to support microspheres during plasma coating

Spherical laser fusion targets can be levitated on beams of Ar or other gas atoms. This is an especially useful and reliable technique for supporting microspheres during plasma coating or plasma etching. The reliability of this technique is principally the result of two things: the success of a special centering device which provides a lateral, stabilizing force on the levitated microspheres; and a gas handling system which is capable of controlling levitation gas flow in the microtorr liter/sec range. We have determined that the operational regime of this device is that of Knudsen's flow. This knowledge of the flow characteristics has been important in developing this device.
Date: August 26, 1980
Creator: Crane, J. K.; Smith, R. D.; Johnson, W. L.; Letts, S. A.; Korbel, G. R. & Krenick, R. M.
System: The UNT Digital Library
Production of slow-positron beams with an electron linac (open access)

Production of slow-positron beams with an electron linac

Intense, pulsed beams of low-energy positrons have been produced by a high-energy beam from an electron linac. The production efficiency for low-energy positrons has been determined for electrons with 60 to 120 MeV energy, low-energy positron beams from a linac can be of much higher intensity than those beams currently derived from radioactive sources.
Date: March 26, 1982
Creator: Howell, R. H.; Alvarez, R. A. & Stanek, M.
System: The UNT Digital Library
Structural Changes Observed in (Mo /sub 6/Ru /sub 4/)/sub x/B/sub 1-x/ Amorphous Alloys Observed with Positron Annihilation (open access)

Structural Changes Observed in (Mo /sub 6/Ru /sub 4/)/sub x/B/sub 1-x/ Amorphous Alloys Observed with Positron Annihilation

Changes in the structure of (Mo /sub 6/Ru /sub 4/)/sub x/B/sub 1-x/ amorphous alloys were observed in positron annihilation analysis using both positron lifetime and Doppler broadening techniques. The changes were introduced into the alloy either by varying the boron fraction or by neutron irradiation. Similar results were observed both in the irradiated alloys and those with vacant boron sites. The positron annihilation data suggest that the modified structure contains regions of open volume and that the positrons interact with those regions.
Date: March 26, 1982
Creator: Howell, R. H. & Johnson, W. L.
System: The UNT Digital Library
A C programmer's view of a relational database (open access)

A C programmer's view of a relational database

The AGS Distributed Control System (AGSDCS) uses a relational database (Interbase) for the storage of all data on the host system network. This includes the static data which describes the components of the accelerator complex, as well as data for application program setup and data records that are used in analysis. By creating a mapping of each elation in the database to a C record and providing general tools for relation (record) across, all the data in the database is available in a natural fashion (in structures) to all the C programs on any of the nodes of the control system. In this paper the correspondence between the Interbase elations and the C structure is detailed with examples of C typedefs and relation definitions. It is also shown how the relations can be put into memory and linked (related) together when fast access is needed by programs. 1 ref., 2 tabs.
Date: October 26, 1989
Creator: Clifford, T.; Katz, R. & Griffiths, C.
System: The UNT Digital Library
Mathematical definition of protocol translation (open access)

Mathematical definition of protocol translation

This paper mathematically defines protocol translation which is a function employed to interconnect different computer networks. An example of an application is a gateway.
Date: March 26, 1982
Creator: Ong, M. M.
System: The UNT Digital Library
Oklahoma's Residential High School: Cultivating Scholars (open access)

Oklahoma's Residential High School: Cultivating Scholars

First page of an article on the creation of a special residential high school in Oklahoma, wherein Texas is mentioned as a state that has already done so.
Date: October 26, 1987
Creator: unknown
System: The UNT Digital Library
Biomodal spontaneous fission (open access)

Biomodal spontaneous fission

Investigations of mass and kinetic-energy distributions from spontaneous fission have been extended in recent years to an isotope of element 104 and, for half-lives, to an isotope of element 108. The results have been surprising in that spontaneous fission half-lives have turned out to be much longer than expected and mass and kinetic- energy distributions were found to abruptly shift away from those of the lighter actinides, showing two modes of fission. These new developments have caused a re-evaluation of our understanding of the fission process, bringing an even deeper appreciation of the role played by nuclear shell effects upon spontaneous fission properties. 16 refs., 10 figs.
Date: September 26, 1989
Creator: Hulet, E.K. (Lawrence Livermore National Lab., CA (USA))
System: The UNT Digital Library
Development of an operational multicomponent personnel neutron dosimeter/spectrometer DOSPEC (open access)

Development of an operational multicomponent personnel neutron dosimeter/spectrometer DOSPEC

A multicomponent dosimeter has been developed that uses an albedo detector to provide the measurement of low energy neutrons and as a screening element. It also contains track detector components, CR-39 and polycarbonate, which are only processed if the TLD indicates there has been an exposure to neutrons. Since the three components have significantly different energy responses, the dosimeter can act as a crude spectrometer. This report describes the dosimeter and briefly summarizes its use experience. 10 refs., 2 figs., 2 tabs.
Date: October 26, 1983
Creator: Griffith, R.V. & McMahon, T.A.
System: The UNT Digital Library
Fabrication of a Set of Realistic Torso Phantoms for Calibration of Transuranic Nuclide Lung Counting Facilities (open access)

Fabrication of a Set of Realistic Torso Phantoms for Calibration of Transuranic Nuclide Lung Counting Facilities

A set of 16 tissue equivalent torso phantoms has been fabricated for use by major laboratories involved in counting transuranic nuclides in the lung. These phantoms, which have bone equivalent plastic rib cages, duplicate the performance of the DOE Realistic Phantom set. The new phantoms (and their successors) provide the user laboratories with a highly realistic calibration tool. Moreover, use of these phantoms will allow participating laboratories to intercompare calibration information, both on formal and informal bases. 3 refs., 2 figs.
Date: October 26, 1983
Creator: Griffith, R. V.; Anderson, A. L.; Sundbeck, C. W. & Alderson, S. W.
System: The UNT Digital Library
Control of gas input and background pressure in the end plug regions of the TMX-U thermal barrier experiment (open access)

Control of gas input and background pressure in the end plug regions of the TMX-U thermal barrier experiment

Rate equations for the plasma species in a thermal barrier end plug establish an upper bound on the neutral pressure (P) external to the plasma. For the Tandem Mirror Experiment-Upgrade (TMX-U), this bound is P less than or equal to 0.5 - 1.0 x 10/sup -6/ Torr. Initially TMX-U did not satisfy this criterion, and axial end plugging of plasma losses seemed limited by the excessive pressure. Subsequently, we modified the machine to improve the vacuum conditions, decreasing P to the desired range. At the same time axial end plugging of plasma losses increased to the duration of neutral beam injection and ECRH heating. Here we summarize our experimental measurements of gas input.
Date: October 26, 1983
Creator: Turner, W. C.; Nexsen, W. E.; Allen, S. L.; Hooper, E. B.; Hunt, A. L.; Lang, D. D. et al.
System: The UNT Digital Library
Rate Dependent Inelastic Behavior of Polycrystalline Solids Using a Dislocation Model (open access)

Rate Dependent Inelastic Behavior of Polycrystalline Solids Using a Dislocation Model

A rate dependent theory of polycrystalline plasticity is presented in which the solid is modeled as an isotropic continuum with internal variables. The rate of plastic deformation is shown to be a function of the deviatoric portion of the Cauchy stress tensor as well as two scalar internal variables. The scalar internal variables, which are the dislocation density and mobile fraction, are governed by rate equations which reflect the evolution of microstructural processes. The model has been incorporated into a two dimensional finite element code and several example multidimensional problems are presented which exhibit the rate dependence of the material model.
Date: February 26, 1980
Creator: Werne, R. W. & Kelly, J. M.
System: The UNT Digital Library
Positron-annihilation studies of molybdenum irradiated by protons, neutrons, or electrons (open access)

Positron-annihilation studies of molybdenum irradiated by protons, neutrons, or electrons

Annealed molybdenum was irradiated at room temperature by energetic protons or neutrons and the fluence and recoil energy dependence of two traps was measured. Comparison of trapping rates with calculations of damage energy correlates high energy recoils with the short lifetime trap and low energy recoils with the longer lifetime.
Date: March 26, 1982
Creator: Howell, R.H.
System: The UNT Digital Library
Executive committee report: geotechnical instrumentation working group meeting (open access)

Executive committee report: geotechnical instrumentation working group meeting

Responding to the widespread need for the geotechnical community to discuss instrumentation for nuclear waste repositories, a meeting was held December 2 and 3, 1981, in Denver, Colorado. This report gives the group's consensus recommendations to aid in making decisions for development of instrumentation for future repository work. The main conclusions of the working group meeting were as follows: (1) monitoring of geotechnical parameters in nuclear waste repositories will be necessary to meet licensing requirements; (2) currently available instruments are underdeveloped for this monitoring; (3) research and development to provide adequate instrumentation will need to be performed under federal sponsorship by national laboratories, universities, contractors, and consultants; and (4) a NASA-type reliability program is needed to meet the quality assurance, durability, calibration, and time schedule demands of geotechnical instrumentation development. This will require significant financial commitments from the federal sector.
Date: April 26, 1982
Creator: Wilder, D. G.; Rogue, F.; Beloff, W. R.; Binnall, E. & Gregory, E. C.
System: The UNT Digital Library
Proceedings of the workshop on the impact of hydrogen on water reactor safety. Volume II of IV (open access)

Proceedings of the workshop on the impact of hydrogen on water reactor safety. Volume II of IV

Separate abstracts were prepared for the papers presented in the subject area: hydrogen sources and detection.
Date: January 26, 1981
Creator: Berman, M. (ed.)
System: The UNT Digital Library
Liquid to gas leak ratios with liquid nitrogen and liquid helium (open access)

Liquid to gas leak ratios with liquid nitrogen and liquid helium

To predict the leak rates of liquid helium and liquid nitrogen containers at operating conditions we need to know how small leaks (10/sup -8/ to 10/sup -5/ atm-cm/sup 3/ air/s), measured at standard conditions, behave when flooded with these cryogens. Two small leaks were measured at ambient conditions (approx.750 Torr and 295 K), at the normal boiling points of LN/sub 2/ and LHe, and at elevated pressures above the liquids. The ratios of the leak rates of the liquids at ambient pressure to the gases (G) at ambient pressure and room temperature were: GN/sub 2/(1), LN/sub 2/(18), GHe(1), and LHe(172). The leak rate ratio of LN/sub 2/ at elevated pressure was linear with pressure. The leak rate ratio of LHe at elevated pressure was also linear with pressure.
Date: February 26, 1985
Creator: Batzer, T. H. & Call, W. R.
System: The UNT Digital Library
Nuclear performance optimization of the Be/Li/Th blanket for the fusion breeder (open access)

Nuclear performance optimization of the Be/Li/Th blanket for the fusion breeder

More rigorous nuclear analysis, including treatment of resonance self-shielding effects coupled with an optimization procedure, has resulted in improved performance of the Be/Li/Th blanket. Net U-233 breeding ratio has increased 36% (to 0.84) while at an average U-233/Th ratio of 0.5 a/o average energy multiplication has increased only 12% (to 2.1) compared with earlier results.
Date: February 26, 1985
Creator: Lee, J. D. & Bandini, B. R.
System: The UNT Digital Library
Opportunistic replacement of fusion power system parts (open access)

Opportunistic replacement of fusion power system parts

This paper describes a maintenance problem in a fusion power plant. The problem is to specify which life limited parts should be replaced when there is an opportunity. The objective is to minimize the cost rate of replacement parts and of maintenance actions while satisfying a power plant availability constraint. The maintenance policy is to look ahead and replace all parts that will reach their life limits within a time called a screen. Longer screens yield greater system availabilities because more parts are replaced prior to their life limits.
Date: October 26, 1981
Creator: Day, J.A. & George, L.L.
System: The UNT Digital Library
Microprocessor control and data acquisition at the LLNL 100-MeV accelerator (open access)

Microprocessor control and data acquisition at the LLNL 100-MeV accelerator

A distributed microprocessor control and data acquisition network has been designed for implementation on the Lawrence Livermore National Laboratory 100 MeV electron/positron accelerator (LINAC). The system has been designed to be as transparent to the user as possible by stressing responsiveness, reliability, and relevance of data presented to the user. Implementation of the network will take place in modular fashion in three stages, so as to minimize disruption of normal operations. The first elements to be installed will be the beam transport system controls, beam set-up time. Beam diagnostic equipment is now being position monitors, and accelerator operating status monitors. These units will reduce beam set-up time. Beam diagnostic equipment is now being designed that will be used in a second stage implementation. This stage will concentrate on determining beam parameters and allowing the user to optimize the beam for a given parameter. The final stage will be to install experimenter data acquisition equipment. The equipment will augment the presently existing data acquisition system. The completed network will allow a more efficient operation of the LINAC, resulting in reduced experiment costs, and more controllable beam parameters, both of which are major concerns of experimenters.
Date: May 26, 1981
Creator: Mendonca, M.L.
System: The UNT Digital Library
1963 revisited: should we set a precedent of recalculating old exposures (open access)

1963 revisited: should we set a precedent of recalculating old exposures

This paper describes recent experience in re-evaluating the dose to an employee. This employee was plagued with skin disorders for years, but he questioned his recorded beta dose only after a recent LLNL cancer study began collecting data. He was concerned that his radiation dose recorded during the time he worked on a fission burst reactor experiment in 1963 did not represent the actual dose he received. About six months were spent gathering information, putting the information together, making necessary calculations, and reaching a reasonable result (a reasonable result being one for which the known information fits the calculated results with a minimum of inconsistencies). This paper presents the beta and gamma whole-body and hand radiation dose calculations, and compares these calculated dose rates with the meter, film, and pocket dosimeter information recorded in the health and safety log, operation log, and dosimetry record.
Date: October 26, 1981
Creator: Hoots, S.S.
System: The UNT Digital Library
TMX-axisymmetric magnet-set-design study (open access)

TMX-axisymmetric magnet-set-design study

Studies are currently being made to design an axisymmetric modification to the TMX-Upgrade experiment. The existing TMX-Upgrade quadrupole plug and transition magnet sets are replaced by the circular coils of an axisymmetric plug. The existing TMX-Upgrade magnet set is shown. The circular coils are sectioned to show the quadrupole magnets and the flux bundle. The two end cells of this magnet set are MHD stable minimum-B plugs. From a mechanical design viewpoint, an axisymmetric design is attractively simple. One of the axisymmetric designs under consideration is the Modified Cusp. A magnet set for this designs is shown. The coils are sectioned to show their cross-section.
Date: October 26, 1981
Creator: Wong, R. L.; Chargin, A. K. & Logan, B. G.
System: The UNT Digital Library
Probing electroweak symmetry breaking at multi-TeV colliders (open access)

Probing electroweak symmetry breaking at multi-TeV colliders

Low energy theorems are derived for scattering of longitudinally polarized W and Z's, providing the basis for an estimate of the observable signal if electroweak symmetry breaking is due to new physics at the TeV scale. A pp collider with L, {radical}s {equals} 40 TeV, 10{sup 33}cm. {sup {minus}2}s{sup {minus}1} is just sufficient to observe the signal while pp colliders with 40, 10{sup 32} or 20, 10{sup 33} are not. A collider that is sensitive to the TeV-scale signal provides valuable information about symmetry breaking whether the masses of the associated new particles are below, within, or above the 1-2 TeV region. 6 refs., 6 figs., 2 tabs.
Date: March 26, 1987
Creator: Chanowitz, Michael S.
System: The UNT Digital Library