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Vanadium-base alloys for fusion reactor applications (open access)

Vanadium-base alloys for fusion reactor applications

Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R and D) needs are defined.
Date: October 1, 1984
Creator: Smith, D. L.; Loomis, B. A. & Diercks, D. R.
System: The UNT Digital Library
Magnetism and Superconductivity in Eu(Ho)Mo/sub 6/S/sub 8/ (open access)

Magnetism and Superconductivity in Eu(Ho)Mo/sub 6/S/sub 8/

A variety of ambient and high pressure experimental results reveal the interplay between magnetism and superconductivity in Ho doped samples of the pressure induced superconductor, EuMo/sub 6/S/sub 8/. Ho concentrations up to 50 atomic percent of the rare earth ions were used. High resolution magnetic measurements are consistent with the crystalline electric field ground state for the Ho/sup 3 +/ ions being a magnetic doublet consisting largely of J/sub z/ = 18. The results of high pressure magnetization experiments reveal negligible effects of reduced lattice constant on the rare earth-rare earth interactions. Resistivity in a 10 atomic percent sample for P = 10 kbar shows the suppression of a P = 0 structural transition, metallic conductivity down to low temperatures, and finally superconductivity at 8 K. The upper critical field, H/sub c2/(T), for this sample was measured for P = 7, 10 and 12 kbar and showed strong reentrant behavior (dH/sub c2/(T)/dT > 0 as T ..-->.. 0 K). A minimum with field in the resistivity above H/sub c2/ was also observed at lowest temperatures. The H/sub c2/(T) data are compared with those of EuMo/sub 6/S/sub 8/ at high pressure, which shows positive curvature, and HoMo/sub 6/S/sub 8/, in which …
Date: October 1, 1984
Creator: Capone, D. W., II; Lai Fook, M. S.; Guertin, R. P.; Hinks, D. G.; Dunlap, B. D.; Foner, S. et al.
System: The UNT Digital Library
Doubled-ended breaks in reactor primary piping. [Guillotine breaks] (open access)

Doubled-ended breaks in reactor primary piping. [Guillotine breaks]

Results indicate that the probability of double-ended guillotine break (DEGB) in the reactor coolant loop piping of Westinghouse and Combustion Engineering plants is extremely low. It is recommended that the NRC seriously consider eliminating DEGB as a design basis event for reactor coolant loop piping in Westinghouse plants. Pipe whip restraints on reactor coolant loop piping could then be excluded or removed, and the requirement to design supports to withstand asymmetric blowdown loads could be eliminated. It is also recommended that the current requirement to couple safe shutdown earthquake (SSE) and DEGB be eliminated. Recognizing however that seismically induced support failure is the weak link in the DEGB evaluation, it is recommended that the strength of component supports, currently designed for the combination of SSE plus DEGB, not be reduced. The study indicates that the probability of DEGB in reactor coolant loop piping is sufficiently low under all plant conditions, including seismic events, to justify eliminating it entirely as a basis for plant design.
Date: October 1, 1984
Creator: Holman, G.S.
System: The UNT Digital Library
Design of a semi-custom integrated circuit for the SLAC SLC timing control system (open access)

Design of a semi-custom integrated circuit for the SLAC SLC timing control system

A semi-custom (gate array) integrated circuit has been designed for use in the SLAC Linear Collider timing and control system. The design process and SLAC's experiences during the phases of the design cycle are described. Issues concerning the partitioning of the design into semi-custom and standard components are discussed. Functional descriptions of the semi-custom integrated circuit and the timing module in which it is used are given.
Date: October 1, 1984
Creator: Linstadt, E.
System: The UNT Digital Library
Collisional pumping for the production of intense spin-polarized, neutral beams: target considerations (open access)

Collisional pumping for the production of intense spin-polarized, neutral beams: target considerations

We have recently proposed a new method for the production of nuclear-spin-polarized ions and atoms. A fast beam of atoms is pumped to a single spin state by means of successive capture of a spin-polarized electron followed by the loss of an electron, in a highly electron-spin-polarized medium. This process, which we call collisional pumping, is characterized by the transfer of the electron spin to the nucleus through hyperfine interactions whenever the atom is in a neutral state. We anticipate that fast polarized beams of 1A or more can be produced, with possible applications to accelerators and fusion research. This process can be accomplished by passage of a low-energy (approx. 1 keV/u) H/sup +/ (D/sup +/,T/sup +/) beam through a polarized alkali-metal-vapor target of about 10/sup 16/ electron-spin-polarized atoms/cm/sup 2/. The only bound state of a negative hydrogen ion is a singlet state, which provides a selection mechanism by making electron attachment impossible when the projectile and target electrons have the same spin.
Date: October 1, 1984
Creator: Stearns, J. W.; Burrell, C. F.; Kaplan, S. N.; Pyle, R. V.; Ruby, L. & Schlachter, A. S.
System: The UNT Digital Library
Development of proportional counters using photosensitive gases and liquids (open access)

Development of proportional counters using photosensitive gases and liquids

An introduction to the history and to the principle of operation of wire chambers using photosensitive gases and liquids is presented. Their use as light sensors coupled to Gas Scintillation Proportional Counters and BaF/sub 2/, as well as their use in Cherenkov Ring imaging, is discussed in some detail. 42 references, 21 figures.
Date: October 1, 1984
Creator: Anderson, D.F.
System: The UNT Digital Library
Proposal for the systematic naming of mesons and baryons (open access)

Proposal for the systematic naming of mesons and baryons

Twenty years ago, the Particle Data Group adopted a systematic naming convention for baryons: the symbols N, ..delta.., ..lambda.., ..sigma.., ..xi.., and ..cap omega.. were to identify the isospin and strangeness, The mesons, by contrast, have become an alphabet soup of uninformative names - theta, iota, xi, zeta, g/sub T/, g/sub s/, H, E, delta, h, g, r, kappa, etc. -, and in some cases identical names are used for mesons with different quantum numbers (A, B, and D). Furthermore, experimentalists are now discovering baryons that contain heavy quarks. It is therefore timely to consider systematic naming conventions both for mesons and for baryons with heavy quarks. The Particle Data Group is circulating this proposal in the hope of generating feedback, and we attach a sheet for responses. It should be emphasized that the Particle Tables would show both the old and new names for some time.
Date: October 1, 1984
Creator: Porter, F. C.; Hernandez, J. J.; Montanet, L.; Roos, M.; Toernqvist, N. A.; Barnett, R. M. et al.
System: The UNT Digital Library
Versatile CAMAC power supply controller-monitor with built-in ramping and ripple monitor (open access)

Versatile CAMAC power supply controller-monitor with built-in ramping and ripple monitor

An integrated power supply controller-monitor has been designed and is in use to control large power supplies for SLC dc magnets. This single-width CAMAC module contains a 14-bit DAC, a 14-bit ADC, and several channels of optically coupled digital status and control signals. Additional features include built-in selectable ramping rates, self-test capabilities, and a ripple monitor circuit to measure ac ripple in the power supply current.
Date: October 1, 1984
Creator: Kang, H. & Horelick, D.
System: The UNT Digital Library
Negative lithium emission from a tungsten surface in a plasma (open access)

Negative lithium emission from a tungsten surface in a plasma

Three possibilities for making Li/sup -/ ions have been considered: electron capture in a suitable gas or vapor, extraction from a lithium plasma, and production on a low work function surface in a plasma. The only quantitative results, so far, have been for electron capture, with the highest yield being about 5% for Li/sup +/ in Cs vapor at 5 keV. Of the other two methods, Leung has seen some Li/sup -/ produced in the volume of a plasma, and we now report the observation of Li/sup -/ from a surface in a He-Li plasma.
Date: October 1, 1984
Creator: Stearns, J. W. & Pyle, R. V.
System: The UNT Digital Library
Fast timing methods for semiconductor detectors. Revision (open access)

Fast timing methods for semiconductor detectors. Revision

This tutorial paper discusses the basic parameters which determine the accuracy of timing measurements and their effect in a practical application, specifically timing with thin-surface barrier detectors. The discussion focusses on properties of the detector, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, noiseless input terminations in sub-nanosecond preamplifiers and methods using transmission lines to couple the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effective rise time, equivalent input noise and residual jitter.
Date: October 1, 1984
Creator: Spieler, H.
System: The UNT Digital Library
Experiments with heavy beams at the Berkeley Bevalac (open access)

Experiments with heavy beams at the Berkeley Bevalac

Some of the early results obtained with heavy beams (A greater than or approx. = 100) at the Bevalac are presented. My intention is to give you a flavor of the research program that has developed in the early 1980's with the capability of accelerating nuclei spanning the full periodic table. 11 references, 8 figures.
Date: October 1, 1984
Creator: Schroeder, L. S.
System: The UNT Digital Library
Development of generic floor response spectra for equipment qualification for seismic loads (open access)

Development of generic floor response spectra for equipment qualification for seismic loads

A generic floor response spectra has been developed for use in the qualification of electrical and mechanical equipment in operating nuclear power plants. Actual PWR and BWR - Mark I structural models were used as representative of a class of structures. For each model, the stiffness properties were varied, with the same mass, so as to extend the fundamental base structure natural frequency from 2 cps to 36 cps. This resulted in fundamental mode coupled natural frequencies as low as 0.86 cps and as high as 30 cps. The characteristics of 1000 floor response spectra were studied to determine the generic spectra. A procedure for its application to any operating plant has been established. The procedure uses as much or as little information that currently exists at the plant relating to the question of equipment qualification. A generic floor response spectra is proposed for the top level of a generic structure. Reduction factors are applied to the peak acceleration for equipment at lower levels.
Date: October 1, 1984
Creator: Curreri, J.R. & Costantino, C.J.
System: The UNT Digital Library
Summary report of the Jet-Study Group (open access)

Summary report of the Jet-Study Group

Predictions for jet physics at SSC energies are reviewed. Comparison is made with data at CERN collider energies. The work of the Jet-Study Group had much overlap with the work of the Detector Groups and the Fragmentation Group. 22 references.
Date: October 1, 1984
Creator: Ellis, R.K. & Rohlf, J.
System: The UNT Digital Library
Vernier Delay Unit (open access)

Vernier Delay Unit

This module will accept differential ECL pulses from the auxiliary rear panel or NIM level pulses from the front panel. The pulses are produced at the output with a fixed delay that is software programmable in steps of 0.1 ns over the range of 0.1 to 10.5 ns. Multiple outputs are available at the front panel. Minimum delay through the module is 9 ns.
Date: October 1, 1984
Creator: Pierce, W.B.
System: The UNT Digital Library
Eleven lectures on the physics of the quark-gluon plasma (open access)

Eleven lectures on the physics of the quark-gluon plasma

These lectures are intended to be an introduction to the physics of the quark-gluon plasma, and were presented at a workshop on The Physics of the Quark-Gluon Plasma held at Hua-Zhong Normal University in Wuhan, People's Republic of China in September, 1983. The lectures cover perturbation theory of the plasma at high temperature as well as the non-perturbative methods and results of lattice gauge theory computations. Physical models of the confinement-deconfinement phase transition and the modes of chiral symmetry breaking are presented. The possibility that a quark-gluon plasma might be produced in ultra-relativistic nuclear collisions is analyzed. Separate entries were prepared for the data base for the eleven lectures.
Date: October 1, 1984
Creator: McLerran, L.
System: The UNT Digital Library
Super-collider: progress, options and physics (open access)

Super-collider: progress, options and physics

The Superconducting Super Collider (SSC) has been given high priority by the high energy physics community. Various aspects of the project - physics motivation, accelerator design, siting considerations - are discussed here. The project is moving rapidly and parts of this discussion have been updated to reflect the vast amount of work that has gone into the SSC since the conference.
Date: October 18, 1984
Creator: Diebold, R.
System: The UNT Digital Library
Microstructural examination of fast-neutron irradiated Li/sub 2/O (open access)

Microstructural examination of fast-neutron irradiated Li/sub 2/O

Scanning Electron Microscopy examinations of fast-neutron irradiated Li/sub 2/O at 608 to 625/sup 0/C to 1 and 3 at. % /sup 6/Li burnups have been performed. Of particular interests are the helium bubble morphologies and their relationships to the reported tritium/helium retentions and swelling in Li/sub 2/O. Possible defect trapping of tritium is suggested, along with discussions of two other phenomena (microcracking, swelling) on the performance of an Li/sub 2/O fusion reactor blanket.
Date: October 1, 1984
Creator: Liu, Y. Y.; Mattas, R. F.; Smith, D. L. & Porter, D. L.
System: The UNT Digital Library
Pion production and the nuclear equation of state (open access)

Pion production and the nuclear equation of state

There has been considerable recent interest in the nuclear equation of state and how it may be determined in relativistic nucleus-nucleus collisions. In these collisions extremely high temperatures are reached and compression to densities several times that of normal nuclear matter are predicted. This affords us the unique opportunity to study, in a somewhat controlled manner, the behavior of nuclear matter under these extreme conditions. If the observables that are measured in experiments can be related in a quantitative way to state variables of the system then the equation of state can be extracted. This relation plays a very important role in understanding the formation and collapse of supernovae and the stability and structure of neutron stars. Furthermore, it can be used to test and constrain field theoretical approaches to nuclear matter and to help to better understand the dynamics of high energy nucleus-nucleus collisions. In this presentation the relationship between the nuclear equation of state and relativistic nucleus-nucleus collisions will be discussed with an emphasis on how to extract the former. That a high density state of the collision should exist will be shown. One observable, namely the pion multiplicity, will be shown to survive the succeeding stages of …
Date: October 1, 1984
Creator: Harris, J. W.; Odyniec, G.; Pugh, H. G.; Schroeder, L. S.; Tincknell, M. L.; Bock, R. et al.
System: The UNT Digital Library
Phase Transitions and Dark Matter Problems (open access)

Phase Transitions and Dark Matter Problems

The possible relationships between phase transitions in the early universe and dark matter problems are discussed. It is shown that there are at least 3 distinct cosmological dark matter problems: (1) halos; (2) galaxy formation and clustering; and (3) ..cap omega.. = 1, each emphasizing different attributes for the dark matter. At least some of the dark matter must be baryonic but if problems 2 and 3 are real they seem to also require non-baryonic material. However, if seeds are generated at the quark-hardon-chiral symmetry transition then alternatives to the standard scenarios may occur. At present no simple simultaneous solution (neither hot, warm, nor cold) exists for all 3 problems, but non-standard solutions with strings, decaying particles or light not tracing to mass may work. An alternative interpretation of the relationship of the cluster-cluster and galaxy-galaxy correlation functions using renormalized scaling is mentioned. In this interpretation galaxies are more strongly correlated and the cluster-cluster function is not expected to go negative until greater than or equal to 200 Mpc. Possible phase transition origins for the cluster-cluster renormalized scale are presented as ways to obtain a dimension 1.2 fractal. 64 references.
Date: October 1, 1984
Creator: Schramm, D. N.
System: The UNT Digital Library
Workshop on electroweak symmetry breaking: proceedings (open access)

Workshop on electroweak symmetry breaking: proceedings

A theoretical workshop on electroweak symmetry breaking at the Superconducting Supercollider was held at Lawrence Berkeley Laboratory, June 4-22, 1984. The purpose of the workshop was to focus theoretical attention on the ways in which experimentation at the SSC could reveal manifestations of the phenomenon responsible for electroweak symmetry breaking. This issue represents, at present, the most compelling scientific argument for the need to explore the energy region to be made accessible by the SSC, and a major aim of the workshop was to involve a broad cross section of particle theorists in the ongoing process of sharpening the requirements for both accelerator and detector design that will ensure detection and identification of meaningful signals, whatever form the electroweak symmetry breaking phenomenon should actually take. Separate entries were prepared for the data base for the papers presented.
Date: October 1, 1984
Creator: Hinchliffe, I. (ed.)
System: The UNT Digital Library
Development of rf plasma generators for neutral beams (open access)

Development of rf plasma generators for neutral beams

The development of low frequency (1-2 MHz) rf plasma generators for high power neutral beam applications is summarized. Immersed couplers from one to three turns were used. Acceptable plasma profiles, less than or equal to 15% max/min, were obtained in a variety of field-free magnetic bucket and magnetic filter-bucket sources, with 10 x 10 cm or 10 x 40 cm extraction areas. Hydrogen beam properties were measured with a 7 x 10 cm accelerator operated at 80 kV. Atomic fraction and power efficiency were at least as high as with arc plasmas in similar chambers. The potential advantages of an rf plasma source are: ease of operation; reliability; and extended service lifetime.
Date: October 1, 1984
Creator: Vella, M. C.; Ehlers, K. W.; Kippenhan, D.; Pincosy, P. A.; Pyle, R. V.; DiVergilio, W. F. et al.
System: The UNT Digital Library
First-wall and limiter conditioning in TFTR (open access)

First-wall and limiter conditioning in TFTR

A progress report on the experimental studies of vacuum vessel conditioning during the first year of TFTR operation is presented. A previous paper described the efforts expended to condition the TFTR vessel prior to and during the initial plasma start-up experiments. During the start-up phase, discharge cleaning was performed with the vessel at room temperature. For the second phase of TFTR operations, which was directed towards the optimization of ohmically heated plasmas, the vacuum vessel could be heated to 150/sup 0/C. The internal configuration of the TFTR vessel was more complex during the second phase with the addition of a TiC/C moveable limiter array, Inconel bellows cover plates, and ZrAl getter pumps. A quantitative comparison is given on the effectiveness of vessel bakeout, glow discharge cleaning, and pulse discharge cleaning in terms of the total quantity of removed carbon and oxygen, residual gas base pressures and the resulting plasma impurity levels as measured by visible, uv, and soft x-ray spectroscopy. The initial experience with hydrogen isotope changeover in TFTR is presented including the results of the attempt to hasten the changeover time by using a glow discharge to precondition the vessel with the new isotope.
Date: October 1, 1984
Creator: Dylla, H.F.; Blanchard, W.R.; Hawryluk, R.J.; Hill, K.W.; Krawchuk, R.B.; Mueller, D. et al.
System: The UNT Digital Library
New drift chamber for the Mark II detector at the SLAC Linear Collider (open access)

New drift chamber for the Mark II detector at the SLAC Linear Collider

The design of the new cylindrical drift chamber for the Mark II detector at the SLAC Linear Collider is described. Prototype tests to determine the working parameters of the chamber and to study possible gas mixtures are discussed.
Date: October 1, 1984
Creator: Burchat, P. R.; Hanson, G. G. & Sadrozinski, H. F. W.
System: The UNT Digital Library
Laser-induced fluorescence of metal-atom impurities in a neutral beam (open access)

Laser-induced fluorescence of metal-atom impurities in a neutral beam

The need to limit impurities in fusion devices to low levels is well known. We have investigated, by the technique of laser-induced fluorescence, the concentration of heavy-metal atoms in a neutral beam caused by their evaporation from the hot filaments in a conventional high-current multifilament hydrogen-ion source.
Date: October 1, 1984
Creator: Burrell, C.F.; Pyle, R.V.; Sabetimani, Z. & Schlachter, A.S.
System: The UNT Digital Library