Searching for 4th generation fermions at high-energy e/sup +/e/sup -/ machines (open access)

Searching for 4th generation fermions at high-energy e/sup +/e/sup -/ machines

This writeup summarizes Monte Carlo studies on the feasibility of searching for 4th family fermions at high energy e/sup +/e/sup -/ machines. By high energy it is meant at energies beyond the Z/sup 0/; the Z/sup 0/ searches having been studied extensively by the SLC and LEP collaborations. The specific examples of ..sqrt..s = 200 GeV (namely LEP200) and ..sqrt..s = 600 GeV (in line with work being done at SLAC to investigate the potential of a future linear collider) were chosen. The studies have been performed with the four vectors produced by the models and no attempt has been made to account for the effects of finite resolution and inefficiencies due to a real detector environment.
Date: May 1, 1987
Creator: Dorfan, J. & Van Kooten, R.J.
Object Type: Article
System: The UNT Digital Library
Design and fabrication of binary-valued alignment reticle patterns (open access)

Design and fabrication of binary-valued alignment reticle patterns

We have studied techniques for alignment reticle fabrication. Two design methods are discussed in this report: one uses an iterative procedure and the other uses results from number theory. A third method was also studied briefly; this being a binary chirp grating. Although this was described in a previous report, we did not find it particularly promising and do not discuss it in this document. It is our opinion that either of the two methods discussed in this report can be made into a workable system if there is sufficient interest. It is also our opinion that the reticle design based on number theory, which uses the polarization encoding of two patterns onto a single substrate, is a powerful method which deserves further consideration.
Date: May 1, 1987
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Challenges of nuclear fusion (open access)

Challenges of nuclear fusion

After 30 years of research and development in many countries, the magnetic confinement fusion experiments finally seem to be getting close to the original first goal: the point of ''scientific break-even.'' Plans are being made for a generation of experiments and tests with actual controlled thermonuclear fusion conditions. Therefore, engineers and material scientists are hard at work to develop the required technology. In this paper the principal elements of a generic fusion reactor are described briefly to introduce the reader to the nature of the problems at hand. The main portion of the presentation summarizes the recent advances made in this field and discusses the major issues that still need to be addressed in regard to materials and technology for fusion power. Specific examples are the problems of the first wall and other components that come into direct contact with the plasma, where both lifetime and plasma contamination are matters of concern. Equally challenging are the demands on structural materials and on the magnetic-field coils, particularly in connection with the neutron-radiation environment of fusion reactors. Finally, the role of ceramics must be considered, both for insulators and for fuel breeding purposes. It is evident that we still have a formidable …
Date: May 1, 1987
Creator: Kunkel, W.B.
Object Type: Article
System: The UNT Digital Library
Face Compression Yield Strength of the Copper-Inconel Composite Specimen (open access)

Face Compression Yield Strength of the Copper-Inconel Composite Specimen

A new equation for the face compression yield strength of copper-Inconel composite material has been derived. Elastic-plastic finite element analyses were also made for composite specimens with various aspect ratios to examine the edge effect of the specimen. According to the results of both the new equation and the analyses, the face compression yield strength of the composite should be decreased by about 25% from the value obtained with Becker's equation.
Date: May 1, 1987
Creator: Horie, T.
Object Type: Report
System: The UNT Digital Library
Physics Division: Annual report, 1 January-31 December 1985 (open access)

Physics Division: Annual report, 1 January-31 December 1985

This report summarizes the research programs of the Physics Division of the Lawrence Berkeley Laboratory during calendar 1985. The Division's principal activities are research in theoretical and experimental high energy physics, and the development of tools such as sophisticated detectors to carry out that research. The physics activity also includes a program in astrophysics, and the efforts of the Particle Data Group whose compilations serve the worldwide high energy physics community. Finally, in addition to the physics program, there is a smaller but highly significant research effort in applied mathematics. Some specific topics included in this report are: Research on e/sup +/e/sup -/ annihilation, superconducting super collider, double beta decay, high energy astrophysics and interdisciplinary experiments, detector research and development, electroweak interactions, strong interaction, quantum field theory, superstrings and quantum gravity, vortex methods and turbulence and computational mathematics.
Date: May 1, 1987
Creator: unknown
Object Type: Report
System: The UNT Digital Library
The maximum likelihood estimator method of image reconstruction: Its fundamental characteristics and their origin (open access)

The maximum likelihood estimator method of image reconstruction: Its fundamental characteristics and their origin

We review our recent work characterizing the image reconstruction properties of the MLE algorithm. We studied its convergence properties and confirmed the onset of image deterioration, which is a function of the number of counts in the source. By modulating the weight given to projection tubes with high numbers of counts with respect to those with low numbers of counts in the reconstruction process, we have confirmed that image deterioration is due to an attempt by the algorithm to match projection data tubes with high numbers of counts too closely to the iterative image projections. We developed a stopping rule for the algorithm that tests the hypothesis that a reconstructed image could have given the initial projection data in a manner consistent with the underlying assumption of Poisson distributed variables. The rule was applied to two mathematically generated phantoms with success and to a third phantom with exact (no statistical fluctuations) projection data. We conclude that the behavior of the target functions whose extrema are sought in iterative schemes is more important in the early stages of the reconstruction than in the later stages, when the extrema are being approached but with the Poisson nature of the measurement. 11 refs., …
Date: May 1, 1987
Creator: Llacer, J. & Veklerov, E.
Object Type: Article
System: The UNT Digital Library
Transport in small and/or random systems (open access)

Transport in small and/or random systems

This report discusses: transport in small systems; electron-phonon interactions in quantum wells; noise in small systems; laser propagation in the atmosphere; laser-aerosol interactions; transport properties of carriers in semiconductor quantum wells; light transmission in a particulate medium; and laser generation of shock waves in droplets. (LSP)
Date: May 14, 1987
Creator: Lax, M.
Object Type: Report
System: The UNT Digital Library
Steady-state deformation of some lithium ceramics (open access)

Steady-state deformation of some lithium ceramics

The stress-strain behavior of Li/sub 2/O, LiAlO/sub 2/ and Li/sub 2/ZrO/sub 3/ polycrystals, with densities varying from 0.70 to 0.95 of the theoretical, has been measured in constant-crosshead-speed compression tests at temperatures of 700 to 1000/sup 0/C with strain rates ranging from about 10/sup -6/ to 10/sup -4/ s/sup -1/. A steady-state stress, sigma/sub s/, for which the work-hardening rate becomes zero, was achieved. These results, therefore, yield information equivalent to that obtained from creep experiments. Limited data on LiAlO/sub 2/ and Li/sub 2/ZrO/sub 3/ were obtained. Nevertheless, under comparable conditions the lithium aluminate and zirconate were considerably stronger than the Li/sub 2/O. This finding may be related to differences in crystal structure. It is, however, likely that in operation as a function breeder blanket material, the oxide will swell whereas the aluminate and the zirconate will crack. 5 refs., 6 figs., 1 tab.
Date: May 1, 1987
Creator: Poeppel, R.B.; Routbort, J.L.; Billone, M.C.; Applegate, D.S.; Buchmann, E. & Londschien, B.
Object Type: Article
System: The UNT Digital Library
Gamma ray measurements during deuterium and /sup 3/He discharges on TFTR (open access)

Gamma ray measurements during deuterium and /sup 3/He discharges on TFTR

Gamma ray count rates and energy spectra have been measured in TFTR deuterium plasmas during ohmic heating and during injection of deuterium neutral beams for total neutron source strengths up to 6 x 10/sup 15/ neutrons per second. The gamma ray measurements for the deuterium plasmas are in general agreement with predictions obtained using simplified transport models. The 16.6 MeV fusion gamma ray from the direct capture reaction D(/sup 3/He,..gamma..)/sup 5/Li was observed during deuterium neutral beam injection into /sup 3/He plasmas for beam powers up to 7 MW. The measured yield of the 16.6 MeV gamma ray is consistent with the predicted yield. The observation of this capture gamma ray establishes the spectroscopy of the fusion gamma rays from the D-/sup 3/He reactions as a viable diagnostic of total fusion reaction rates and benchmarks the modeling for extension of the technique to D-T plasmas. 21 refs., 12 figs.
Date: May 1, 1987
Creator: Cecil, F. E. & Medley, S. S.
Object Type: Report
System: The UNT Digital Library
Reactor Safety Research: Semiannual report, January-June 1986: Reactor Safety Research Program (open access)

Reactor Safety Research: Semiannual report, January-June 1986: Reactor Safety Research Program

Sandia National Laboratories is conducting, under USNRC sponsorship, phenomenological research related to the safety of commercial nuclear power reactors. The research includes experiments to simulate the phenomenology of accident conditions and the development of analytical models, verified by experiment, which can be used to predict reactor and safety systems performance behavior under abnormal conditions. The objective of this work is to provide NRC requisite data bases and analytical methods to (1) identify and define safety issues, (2) understand the progression of risk-significant accident sequences, and (3) conduct safety assessments. The collective NRC-sponsored effort at Sandia National Laboratories is directed at enhancing the technology base supporting licensing decisions.
Date: May 1, 1987
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Generation mixing and CP-violation, standard and beyond (open access)

Generation mixing and CP-violation, standard and beyond

We discuss several issues related to the observed generation pattern of quarks and leptons. Among the main topics: Masses, angles and phases and possible relations among them, a possible fourth generation of quarks and leptons, new bounds on neutrino masses, comments on the recently observed mixing in the B - anti B system, CP-violation, and recent proposals for a b-quark ''factory''.
Date: May 1, 1987
Creator: Harari, H.
Object Type: Article
System: The UNT Digital Library
Interpretation of shallow crustal structure of the Imperial Valley, California, from seismic reflection profiles (open access)

Interpretation of shallow crustal structure of the Imperial Valley, California, from seismic reflection profiles

Eight seismic reflection profiles (285 km total length) from the Imperial Valley, California, were provided to CALCRUST for reprocessing and interpretation. Two profiles were located along the western margin of the valley, five profiles were situated along the eastern margin and one traversed the deepest portion of the basin. These data reveal that the central basin contains a wedge of highly faulted sediments that thins to the east. Most of the faulting is strike-slip but there is evidence for block rotations on the scale of 5 to 10 kilometers within the Brawley Seismic Zone. These lines provide insight into the nature of the east and west edges of the Imperial Valley. The basement at the northwestern margin of the valley, to the north of the Superstition Hills, has been normal-faulted and blocks of basement material have ''calved'' into the trough. A blanket of sediments has been deposited on this margin. To the south of the Superstition Hills and Superstition Mountain, the top of the basement is a detachment surface that dips gently into the basin. This margin is also covered by a thick sequence sediments. The basement of the eastern margin consists of metamorphic rocks of the upper plate of …
Date: May 1, 1987
Creator: Severson, L.K.
Object Type: Report
System: The UNT Digital Library
Small t Physics at the TEVATRON Collider (open access)

Small t Physics at the TEVATRON Collider

The first physics run of the superconducting Tevatron Collider at Fermilab ended this morning. A status report will be presented on the progress of the small angle elastic scattering and total cross section experiment, E710. The goals of this experiment are to measure the total proton-antiproton cross section from ..sqrt..s = 300 to 2000 GeV, the slope of the diffraction peak and rho, the ratio of the real to imaginary part of the forward scattering amplitude, at these energies. 1 ref., 8 figs.
Date: May 11, 1987
Creator: Bertani, M.; Giacomalli, G.; Maleyran, R.; Manarin, A.; Amos, N.; DeSalvo, R. et al.
Object Type: Article
System: The UNT Digital Library
Injection and propagation of a nonrelativistic electron beam and spacecraft charging (open access)

Injection and propagation of a nonrelativistic electron beam and spacecraft charging

Two-dimensional numerical simulations have been carried out in order to study the injection and propagation of a nonrelativistic electron beam from a spacecraft into a fully ionized plasma in a magnetic field. Contrary to the earlier results in one-dimension, a high density electron beam whose density is comparable to the ambient density can propagate into a plasma. A strong radial electric field resulting from the net charges in the beam causes the beam electrons to spread radially reducing the beam density. When the injection current exceeds the return current, significant charging of the spacecraft is observed along with the reflection of the injected electrons back to the spacecraft. Recent data on the electron beam injection from the Spacelab 1 (SEPAC) are discussed.
Date: May 1, 1987
Creator: Okuda, H. & Berchem, J.
Object Type: Report
System: The UNT Digital Library
Progress at LAMPF (Los Alamos Meson Physics Facility): Progress report, January-December 1986 (open access)

Progress at LAMPF (Los Alamos Meson Physics Facility): Progress report, January-December 1986

Activities at LAMPF during the year of 1986 are summarized, including brief summaries of experiments in nuclear and particle physics, atomic and molecular physics, materials science, radiation-effects studies, biomedical research and instrumentation, nuclear chemistry, radioisotope production, and theory. The status of an advanced hadron facility currently under study is reported, as well as facility development and accelerator operations. (LEW)
Date: May 1, 1987
Creator: Allred, J.C. & Talley, B. (eds.)
Object Type: Report
System: The UNT Digital Library
Mixed oxide fuel development (open access)

Mixed oxide fuel development

This paper describes the success of the ongoing mixed-oxide fuel development program in the United States aimed at qualifying an economical fuel system for liquid metal cooled reactors. This development has been the cornerstone of the US program for the past 20 years and has proceeded in a deliberate and highly disciplined fashion with high emphasis on fuel reliability and operational safety as major features of an economical fuel system. The program progresses from feature testing in EBR-II to qualifying full size components in FFTF under fully prototypic conditions to establish a basis for extending allowable lifetimes. The development program started with the one year (300 EFPD) core, which is the FFTF driver fuel, continued with the demonstration of a two year (600 EFPD) core and is presently evaluating a three year (900 EFPD) fuel system. All three of these systems, consistent with other LMR fuel programs around the world, use fuel pellets gas bonded to a cladding tube that is assembled into a bundle and fitted into a wrapper tube or duct for ease of insertion into a core. The materials of construction progressed from austenitic CW 316 SS to lower swelling austenitic D9 to non swelling ferritic/martensitic HT9. …
Date: May 8, 1987
Creator: Leggett, R. D. & Omberg, R. P.
Object Type: Article
System: The UNT Digital Library
Preliminary results on B-anti B mixing from MAC (open access)

Preliminary results on B-anti B mixing from MAC

An excess of like-charge dimuons has been observed with the MAC detector in multihadron events produced in e e annihilation at s = 29 GeV. If this excess is attributed to B - anti B mixing, the corresponding value of the mixing parameter chi = GAMMA(B X)/GAMMA(B X) is chi = 0.21/sub -0.15//sup +0.25/ and chi > 0.02 at 90% C.L.
Date: May 1, 1987
Creator: Hurst, R.
Object Type: Article
System: The UNT Digital Library
Lessons learned from hydrogen generation and burning during the TMI-2 event (open access)

Lessons learned from hydrogen generation and burning during the TMI-2 event

This document summarizes what has been learned from generation of hydrogen in the reactor core and the hydrogen burn that occurred in the containment building of the Three Mile Island Unit No. 2 (TMI-2) nuclear power plant on March 28, 1979. During the TMI-2 loss-of-coolant accident (LOCA), a large quantity of hydrogen was generated by a zirconium-water reaction. The hydrogen burn that occurred 9 h and 50 min after the initiation of the TMI-2 accident went essentially unnoticed for the first few days. Even through the burn increased the containment gas temperature and pressure to 1200/sup 0/F (650/sup 0/C) and 29 lb/in/sup 2/ (200 kPa) gage, there was no serious threat to the containment building. The processes, rates, and quantities of hydrogen gas generated and removed during and following the LOCA are described in this report. In addition, the methods which were used to define the conditions that existed in the containment building before, during, and after the hydrogen burn are described. The results of data evaluations and engineering calculations are presented to show the pressure and temperature histories of the atmosphere in various containment segments during and after the burn. Material and equipment in reactor containment buildings can be …
Date: May 1, 1987
Creator: Henrie, J.O. & Postma, A.K.
Object Type: Report
System: The UNT Digital Library
Heat and mass transfer in the Klamath Falls, Oregon, geothermal system (open access)

Heat and mass transfer in the Klamath Falls, Oregon, geothermal system

Over the last 50 years significant amounts of data have been obtained from the Klamath Falls geothermal resource. To date, the complexity of the system has perplexed researchers, leading to the development of only very generalized hydrogeologic and geothermal models of the area. Based on reevaluation of all available data, a detailed conceptual model for the Klamath Falls geothermal resource is proposed. A comprehensive 3-dimensional numerical model, based on the proposed conceptual model is also presented. This numerical model incorporates all of the main reservoir characteristics. Hot water recharge flows from depth, along a large normal fault, and flows into near surface permeable strata where it loses heat to surrounding beds and to mixing with cold regional groundwaters introduced from the north. By matching calculated and measured temperatures and pressures, hot and cold water recharge rates and the permeability distribution for the geothermal system are estimated. A semi-analytic solution and simple lumped parameter methods are also compared to the numerical analysis. Results suggest that the flow patterns within the geothermal system at Klamath Falls are complex and intimately associated with the permeability distribution and the pressures and temperatures at depth, within the faults.
Date: May 1, 1987
Creator: Prucha, R. H.
Object Type: Report
System: The UNT Digital Library
Testing quantum chromodynamics in electroproduction (open access)

Testing quantum chromodynamics in electroproduction

The exclusive channels in electroproduction are discussed. The study of color transparency, the formation zone, and other novel aspects of QCD by measuring exclusive reactions inside nuclear targets is covered. Diffractive electroproduction channels are discussed, and exclusive nuclear processes in QCD are examined. Non-additivity of nuclear structure functions (EMC effect) is also discussed, as well as jet coalescence in electroproduction. (LEW)
Date: May 1, 1987
Creator: Brodsky, Stanley J.
Object Type: Article
System: The UNT Digital Library
Effect of deuteron temperature on iron forbidden line intensities in rf-heated tokamak plasmas (open access)

Effect of deuteron temperature on iron forbidden line intensities in rf-heated tokamak plasmas

Two line ratios, the forbidden line at 845.5 A (2s/sup 2/2p /sup 2/P/sub 1/2/ - 2s/sup 2/2p /sup 2/P/sub 3/2/) to the allowed line at 135.7 A (2s/sup 2/2p /sup 2/P/sub 1/2/ - 2s2p/sup 2/ /sup 2/D/sub 3/2/) in Fe XXII and the forbidden line at 592.1 A (2s/sup 2/2p/sup 4/ /sup 3/P/sub 2/ - 2s/sup 2/2p/sup 4/ /sup 1/D/sub 2/) to the forbidden line at 1118.2 A (2s/sup 2/2p/sup 4/ /sup 3/P/sub 2/ - 2s/sup 2/2p/sup 4/ /sup 3/P/sub 1/) in Fe XIX, have been measured as the ion temperature-sensitive line ratios during rf heating in the Princeton Large Torus. The results indicate that deuteron collisions in plasmas of high deuteron temperature have a noticeable effect on the intensity of the forbidden lines. Measured relative intensities are compared with values from level population calculations, which include deuteron collisional excitation between the levels of the ground configuration. The agreement between the observed and calculated ratios is within 30%. A method for deuteron (or proton) temperature measurement in tokamak plasmas is discussed. 37 refs.
Date: May 1, 1987
Creator: Sato, K.; Suckewer, S. & Wouters, A.
Object Type: Report
System: The UNT Digital Library
Effects of Impurities on Domain Growth (open access)

Effects of Impurities on Domain Growth

In the present report, the effects of both static and diffusing impurities on domain growth kinetics are considered. In particular, the Monte Carlo simulations for nonconservative (Glauber) dynamics are employed to examine the effects of quenched impurities on domain growth in the Potts model with varying degeneracy Q (2 less than or equal to Q less than or equal to 48). The effects of diffusing impurities are examined within the framework of the Ising model (i.e., Potts model with Q = 2) as a function of impurity diffusivity. Finally, a theoretical analysis of the diffusing-impurity results is presented.
Date: May 1, 1987
Creator: Srolovitz, D. J.; Grest, G. S.; Hassold, G. N. & Eykholt, R.
Object Type: Article
System: The UNT Digital Library
Rf-driver linear colliders (open access)

Rf-driver linear colliders

The next generation of linear collider after the SLC (Stanford Linear Collider) will probably have an energy in the range 300 GeV-1 TeV per linac. A number of exotic accelerating schemes, such as laser and plasma acceleration, have been proposed for linear colliders of the far future. However, the technology which is most mature and which could lead to a collider in the above energy range in the relatively near future is the rf-driven linac, in which externally produced rf is fed into a more or less conventional metallic accelerating structure. Two basic technologies have been proposed for producing the required high peak rf power: discrete microwave power sources, and various two-beam acceleration schemes in which the rf is produced by a high current driving beam running parallel to the main accelerator. The current status of experimental and analytic work on both the discrete source and the two-beam methods for producing rf is discussed. The implications of beam-beam related effects (luminosity, disruption and beamstrahlung) for the design of rf-driven colliders are also considered.
Date: May 1, 1987
Creator: Wilson, Perry B.
Object Type: Article
System: The UNT Digital Library
A scenario for estimating the charge on the electron in terms of Planck's constant and the speed of light (open access)

A scenario for estimating the charge on the electron in terms of Planck's constant and the speed of light

The conjecture that the electron might be a soliton of a non-linearly generalized, charge-free electromagnetic field, together with an estimate of the strength of the hypothetical non-linearity (based on the standard QED calculation of the scattering of light by light) leads to an estimate of the soliton's charge, -e, such that hC/e/sup 2/ turns out to be equal to 45..pi.. multiplied by a number of order one, whose precise value depends on the details of the soliton's radial form factor. 6 refs.
Date: May 1, 1987
Creator: Swiatecki, W.J.
Object Type: Report
System: The UNT Digital Library