35 Years of Electron Scattering (open access)

35 Years of Electron Scattering

A review of the current knowledge of nuclear and nucleon structure gained from electron beam physics is given. Also, the reasons for development of new accelerator facilities (in particular, CEBAF) are discussed.
Date: October 1, 1986
Creator: Walecka, J.
Object Type: Article
System: The UNT Digital Library
Accelerator dynamics and beam aperture (open access)

Accelerator dynamics and beam aperture

We present an analytical method for analyzing accelerator dynamics, including higher order effects of multipoles on the beam. This formalism provides a faster alternative to particle tracking. Simplectic expressions for the emittance and phase describing the dynamical behavior of a particle in a circular accelerator are derived using second order perturbation theory (in the presence of nonlinear elements, e.g., sextupoles, octupoles). These expressions are successfully used to calculate the emittance growth, smear and linear aperture. Our findings compare well with results obtained from tracking programs. In addition perturbation to betatron tune; resonance strengths; stop bandwidth; fixed points; island width; and Chirikov criteria are calculated.
Date: October 1, 1986
Creator: Parsa, Z.
Object Type: Article
System: The UNT Digital Library
Aging degradation of cast stainless steel (open access)

Aging degradation of cast stainless steel

A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. Microstructures of cast materials subjected to long-term aging either in reactor service or in the laboratory have been characterized by TEM, SANS, and APFIM techniques. Two precipitate phases, i.e., the Cr-rich ..cap alpha..' and Ni- and Si-rich G phase, have been identified in the ferrite matrix of the aged steels. The results indicate that the low-temperature embrittlement is primarily caused by ..cap alpha..' precipitates which form by spinodal decomposition. The relative contribution of G phase to loss of toughness is now known. Microstructural data also indicate that weakening of ferrite/austenite phase boundary by carbide precipitates has a significant effect on the onset and extent of embrittlement of the high-carbon CF-8 and CF-8M grades of stainless steels, particularly after aging at 400 or 450/sup 0/C. Data from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 350, 400, and 450/sup 0/C are presented and correlated with the microstructural results. Thermal aging of the steels results in an increase in tensile strength and a decrease in impact energy, J/sub IC/, …
Date: October 1, 1986
Creator: Chopra, O. K. & Chung, H. M.
Object Type: Article
System: The UNT Digital Library
An algorithm for the analysis of inductive antennas of arbitrary cross-section for heating in the ion cyclotron range of frequencies (open access)

An algorithm for the analysis of inductive antennas of arbitrary cross-section for heating in the ion cyclotron range of frequencies

The application of Ion Cyclotron Range of Frequency (ICRF) heating to near ignited plasmas will require launching structures that will be capable of withstanding the harsh plasma environment. The recessed antenna configuration is expected to provide sufficient protection for the structure, but to date no analysis has been done to determine if adequate coupling can be achieved in such a configuration. In this work we present a method for determining the current distribution for the antenna in the direction transverse to current flow and predict antenna loading in the presence of plasma. Antennas of arbitrary cross section are analyzed above ground planes of arbitrary shape. Results from ANDES, the ANtenna DESign code, are presented and compared to experimental results.
Date: October 1, 1986
Creator: Lehrman, I.S. & Colestock, P.L.
Object Type: Report
System: The UNT Digital Library
Analog data transmission via fiber optics (open access)

Analog data transmission via fiber optics

In the SLAC Linear Collider Detector (SLD), as in most high-energy particle detectors, the electromagnetic noise environment is the limiting factor in electronic readout performance. Front-end electronics are particulary susceptible to electromagnetic interference (EMI), and great care has been taken to minimize its effects. The transfer of preprocessed analog signals from the detector environs, to the remote digital processing electronics, by conventional means (via metal conductors), may ultimately limit the performance of the system. Because it is highly impervious to EMI and ground loops, a fiber-optic medium has been chosen for the transmission of these signals. This paper describes several fiber-optic transmission schemes which satisfy the requirements of the SLD analog data transmission.
Date: October 1, 1986
Creator: Cisneros, E. L. & Burgueno, G. F.
Object Type: Article
System: The UNT Digital Library
Analysis and interpretation of a high density tandem negative ion source (open access)

Analysis and interpretation of a high density tandem negative ion source

In the last few years the development of tandem-discharge hydrogen-negative-ion-source systems has proceeded along both experimental and theoretical lines. To some extent these developments have proceeded independently, either the available theoretical model was inadequate to account for a specific geometrical configuration, or the experimental data was not sufficient to provide adequate input parameters for calculation. In the tandem system described here the electron temperature, electron density, and other relevant parameters have been obtained for a high-density system whose electron densities range up to 3 - 5 x 10/sup 12/ electrons cm/sup -3/. The model calculation for the atomic processes has been extended to include both electron density and electron temperature spatial variations through the second chamber. These spatial variations are essential for an adequate interpretation of tandem systems where steep density gradients may occur beyond the magnetic filter region. In this paper we shall combine the experimental density data with the new spatially dependent atomic model for the purpose of attempting a correlation of the observed and calculated current densities. 9 refs., 8 figs., 3 tabs.
Date: October 22, 1986
Creator: Hiskes, J.R.; Lietzke, A.F. & Hauck, C.
Object Type: Article
System: The UNT Digital Library
Analysis of core damage frequency from internal events: Peach Bottom, Unit 2 (open access)

Analysis of core damage frequency from internal events: Peach Bottom, Unit 2

This document contains the internal event initiated accident sequence analyses for Peach Bottom, Unit 2; one of the reference plants being examined as part of the NUREG-1150 effort by the Nuclear Regulatory Commission. NUREG-1150 will document the risk of a selected group of nuclear power plants. As part of that work, this report contains the overall core damage frequency estimate for Peach Bottom, Unit 2, and the accompanying plant damage state frequencies. Sensitivity and uncertainty analyses provided additional insights regarding the dominant contributors to the Peach Bottom core damage frequency estimate. The mean core damage frequency at Peach Bottom was calculated to be 8.2E-6. Station blackout type accidents (loss of all ac power) were found to dominate the overall results. Anticipated Transient Without Scram accidents were also found to be non-negligible contributors. The numerical results are largely driven by common mode failure probability estimates and to some extent, human error. Because of significant data and analysis uncertainties in these two areas (important, for instance, to the most dominant scenario in this study), it is recommended that the results of the uncertainty and sensitivity analyses be considered before any actions are taken based on this analysis.
Date: October 1, 1986
Creator: Kolaczkowski, A.M.; Lambright, J.A.; Ferrell, W.L.; Cathey, N.G.; Najafi, B. & Harper, F.T.
Object Type: Report
System: The UNT Digital Library
Analysis of oxygen on and in beryllium using 2 MeV helium ions (open access)

Analysis of oxygen on and in beryllium using 2 MeV helium ions

Analysis of oxygen on beryllium can be routinely performed using helium-ion backscattering (RBS). However, determination of the bulk oxygen concentration by this technique is limited to about 350 atomic parts per million (appM). We have performed simultaneous RBS and particle-induced x-ray emission (PIXE) measurements to improve the detection limit for bulk oxygen. The RBS measurements allowed determination of the surface oxygen before and after in-situ sputter cleaning by argon ions in an ultra-high-vacuum system. PIXE measurements of specimens with surfaces maintained clean by sputtering permitted assessment of the concentration of oxygen in the bulk. For our geometry and detector sensitivities, 90% of the oxygen x-ray signal originated in the first 2.1 ..mu..m of the beryllium and a detection limit of 10 appM was found. 12 refs., 3 figs.
Date: October 2, 1986
Creator: Musket, R.G.
Object Type: Article
System: The UNT Digital Library
Analysis of the April 18, 1986 UF[sub 6] release test (open access)

Analysis of the April 18, 1986 UF[sub 6] release test

On April 18 1986 a controlled uranium hexafluoride (UF[sub 6])release test was conducted at a CESTA (a French government agency) test site near Bordeaux, France. During the test, 45.8 kg of UF[sub 6] vapor a time interval of 605 s from a 3.15-m high, 0.05-m diameter pipe at a rate of 75.7 kg/s. The exit velocity was 3.46 m/s, and the average exit temperature was 108[degree]C. Information collected during the release test included: meteorological data, measurements of uranium and fluorine concentrations deposition data, and particle size distribution data. Data collected was evaluated and compared to the UF[sub 6] dispersion model.
Date: October 1, 1986
Creator: Just, R. A.
Object Type: Report
System: The UNT Digital Library
Analysis of the April 18, 1986 UF{sub 6} release test. Draft (open access)

Analysis of the April 18, 1986 UF{sub 6} release test. Draft

On April 18 1986 a controlled uranium hexafluoride (UF{sub 6})release test was conducted at a CESTA (a French government agency) test site near Bordeaux, France. During the test, 45.8 kg of UF{sub 6} vapor a time interval of 605 s from a 3.15-m high, 0.05-m diameter pipe at a rate of 75.7 kg/s. The exit velocity was 3.46 m/s, and the average exit temperature was 108{degree}C. Information collected during the release test included: meteorological data, measurements of uranium and fluorine concentrations deposition data, and particle size distribution data. Data collected was evaluated and compared to the UF{sub 6} dispersion model.
Date: October 1, 1986
Creator: Just, R. A.
Object Type: Report
System: The UNT Digital Library
Analytical model for the dynamic resistivity of electrically-exploded conductors (open access)

Analytical model for the dynamic resistivity of electrically-exploded conductors

A detailed model for the dynamic resistivity of an exploding conductor presents many difficulties. An electrically-exploded conductor undergoes significant hydrodynamic expansion as it is heated. Resistivity is a function of both the temperature and density of a conductor and realistic models for resistivity over the range of parameter space experienced by an exploding conductor are quite complex. See for example, the model of Lee and More (1984). Calculation of the hydrodynamic expansion of the conductor during and subsequent to the explosion is likewise dependent on detailed knowledge of the equation of state for the conductor in a range where few experimental data exist. A further complication is the strong magnetic field which couples the hydrodynamic expansion to the currents flowing in the expanding material. In spite of the difficulties, progress is being made on detailed modeling of fuses and exploding conductors (Lidemuth and co-workers, 1985). A simpler approach has proved to be quite useful for modeling the electrical behavior of exploding bridgewire and slapper detonators and for modeling the explosionss of large conductors exploded with large capacitor banks. In the work described here, a simple, empirical model was developed which can be expressed as a closed-form algebraic expression involving four …
Date: October 10, 1986
Creator: Lee, R. S.
Object Type: Article
System: The UNT Digital Library
Analyzing powers and proton spin transfer coefficients in the elastic scattering of 800 MeV polarized protons from an L-type polarized deuteron target at small momentum transfers (open access)

Analyzing powers and proton spin transfer coefficients in the elastic scattering of 800 MeV polarized protons from an L-type polarized deuteron target at small momentum transfers

Analyzing powers and spin transfer coefficients which describe the elastic scattering of polarized protons from a polarized deuteron target have been measured. The energy of the proton beam was 800 MeV and data were taken at laboratory scattering angles of 7, 11, 14, and 16.5 degrees. One analyzing power was also measured at 180 degrees. Three linearly independent orientations of the beam polarization were used and the target was polarized parallel and antiparallel to the direction of the beam momentum. The data were taken with the high resolution spectrometer at the Los Alamos Meson Physics Facility (experiment 685). The results are compared with multiple scattering predictions based on Dirac representations of the nucleon-nucleon scattering matrices. 27 refs., 28 figs., 4 tabs.
Date: October 1, 1986
Creator: Adams, D.L.
Object Type: Report
System: The UNT Digital Library
Anomalous low field magnetization in fine filament NbTi conductors (open access)

Anomalous low field magnetization in fine filament NbTi conductors

The first cable conductors for SSC were made with NbTi filaments whose diameters were in the 18 to 23 micron range. In an effort to reduce the magnetization effects in accelerator dipoles resulting from these large filaments, second generation conductors are now being manufactured with much smaller filaments. As part of this development a series of NbTi conductors were made with filament diameters ranging from 8.0 to 2.8 ..mu..m and having an average interfilament spacing of approximately 12% of filament diameter. Measurements at 4.3 K show that as the filament spacing decreases below a certain critical value the low field magnetization increases rapidly. This increase is seen to be strong function of interfilament distance, magnetic field and temperature. Details of these measurements and its implication for practical high current SSC wire design are discussed.
Date: October 1, 1986
Creator: Ghosh, A.K.; Sampson, W.B.; Gregory, E. & Kreilick, T.S.
Object Type: Article
System: The UNT Digital Library
The application of angular resolved scatter to the documentation of damage to smooth mirrors (open access)

The application of angular resolved scatter to the documentation of damage to smooth mirrors

Mirrors designed to survive exposure to damaging radiation are being irradiated and then measured to determine the mechanisms of failure and to improve the ability of analysis codes to predict an exposure damage threshold. The differences between survival and catastrophic failure are easily recognized and recorded by macro photography. However, the coal of this project is to quantify the onset of mirror degradation utilizing non contact methods that have good measurement sensitivity to small changes in reflectivity (material properties) and light scatter (roughness). A new angular resolved scatterometer is described that has an extended dynamic range and integrated analysis capable of displaying the surface power spectral density (PSD) over large bandwidths of surface spatial frequencies. Graphical displays of the scattered light power before and after exposure to the radiation are compared and integrated over equivalent spatial bandwidths of sensitivity for other instruments to compare calculated RMS roughness values.
Date: October 30, 1986
Creator: Gillespie, C. H.; Edwards, David F. & Stover, John C.
Object Type: Article
System: The UNT Digital Library
ARAC: a centralized computer assisted emergency planning, response, and assessment system for atmospheric releases of toxic material (open access)

ARAC: a centralized computer assisted emergency planning, response, and assessment system for atmospheric releases of toxic material

The Atmospheric Release Advisory Capability (ARAC) is an emergency planning, response, and assessment service, developed by the US Departments of Energy and Defense, and focused, thus far, on atmospheric releases of nuclear material. For the past 14 years ARAC has responded to over 150 accidents, potential accidents, and major exercises. The most notable accident responses are the COSMOS 954 reentry, the Three Mile Island (TMI-2) accident and subsequent purge of /sup 85/Kr from the containment vessel, the recent UF/sub 6/ accident at the Kerr-McGee Plant, Gore, Oklahoma, and the Chernobyl nuclear reactor accident in the Soviet Union. Based on experience in the area of emergency response, developed during the past 14 years, this paper describes the cost effectiveness and other advantages of a centralized emergency planning, response, and assessment service for atmospheric releases of nuclear material.
Date: October 1, 1986
Creator: Dickerson, Marvin H. & Knox, Joseph B.
Object Type: Article
System: The UNT Digital Library
Assessment of strength limiting flaws in ceramic heat exchanger components: Phase 1, Final report, September 28, 1984-June 30, 1986 (open access)

Assessment of strength limiting flaws in ceramic heat exchanger components: Phase 1, Final report, September 28, 1984-June 30, 1986

Assurance of energy efficient design lifetimes of high temperature structural ceramics requires the ability to specify acceptance criteria and to test to those criteria. These criteria will be established through nondestructive testing, to determine which defects are detectable, together with fracture mechanics, to calculate effects of indetectable flaws. The first phase of this program is to examine heat exchanger material with four test methods which have shown promise for use in ceramics; ultrasonic scanning, microfocus x-ray, Scanning Laser Acoustic Microscope, and Acoustic Holography. The capabilities, limits, and potential for improvement of these are presented in this report. Destructive testing, material sectioning, and fractography are included. 24 refs., 68 figs., 6 tabs.
Date: October 1, 1986
Creator: Powers, T. & Snyder, J.
Object Type: Report
System: The UNT Digital Library
Bevalac operations update. No. 3 (open access)

Bevalac operations update. No. 3

Activities are reported in these areas: Bevatron operations (including a list of major experimental runs), user support at the Bevalac, modifications to the local injector, accelerator improvements at the Super HILAC, and general Bevalac upgrading. Modifications are reported for six individual beam lines. (LEW)
Date: October 1, 1986
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Biological Upgrading of Coal-Derived Synthesis Gas: Final Report (open access)

Biological Upgrading of Coal-Derived Synthesis Gas: Final Report

The technical feasibility of the biological conversion of coal synthesis gas to methane has been demonstrated in the University of Arkansas laboratories. Cultures of microorganisms have been developed which achieve total conversion in the water gas shift and methanation reactions in either mixed or pure cultures. These cultures carry out these conversions at ordinary temperatures and pressures, without sulfur toxicity. Several microorganisms have been identified as having commercial potential for producing methane. These include a mixed culture of unidentified bacteria; P. productus which produces acetate, a methane precursor; and Methanothrix sp., which produces methane from acetate. These cultures have been used in mixed reactors and immobilized cell reactors to achieve total CO and H/sub 2/ conversion in a retention time of less than two hours, quite good for a biological reactor. Preliminary economic projections indicate that a biological methanation plant with a size of 5 x 10/sup 10/ Btu/day can be economically attractive. 42 refs., 26 figs., 86 tabs.
Date: October 1, 1986
Creator: Barik, S.; Johnson, E. R.; Ko, C. W.; Clausen, E. C. & Gaddy, J. L.
Object Type: Report
System: The UNT Digital Library
Booster parameter list (open access)

Booster parameter list

The AGS Booster is designed to be an intermediate synchrotron injector for the AGS, capable of accelerating protons from 200 MeV to 1.5 GeV. The parameters listed include beam and operational parameters and lattice parameters, as well as parameters pertaining to the accelerator's magnets, vacuum system, radio frequency acceleration system, and the tunnel. 60 refs., 41 figs. (LEW)
Date: October 1, 1986
Creator: Parsa, Z.
Object Type: Report
System: The UNT Digital Library
Brightness and coherence of synchrotron radiation and high-gain free electron lasers (open access)

Brightness and coherence of synchrotron radiation and high-gain free electron lasers

The characteristics of synchrotron radiation are reviewed with particular attention to its phase-space properties and coherence. The transition of the simple undulator radiation to more intense, more coherent high-gain free electron lasers, is discussed.
Date: October 1, 1986
Creator: Kim, K. J.
Object Type: Article
System: The UNT Digital Library
BWR pipe crack remedies evaluation (open access)

BWR pipe crack remedies evaluation

This paper presents results on: (a) the influence of simulated BWR environments on the stress-corrosion-craking (SCC) susceptibility of Types 304, 316NG, and 347 stainless (SS); (b) fracture-mechanics crack-growth-rate measurements on these materials and weld overlay specimens in different environments; and (c) residual stress measurements and metallographic evaluations of conventional pipe weldments treated by a mechanical-stress-improvement process (MSIP) as well as those produced by a narrow-gap welding procedure. Crack initiation studies on Types 304 and 316NG SS under crevice and non-crevice conditions in 289/sup 0/C water containing 0.25 ppM dissolved oxygen with low sulfate concentrations indicate that SCC initiates at very low strains (<3%) in the nuclear grade material. Crack growth measurements on fracture-mechanics-type specimens, under low-frequency cyclic loading, show that the Type 316NG steel cracks at a somewhat lower rate (approx.40%) than sensitized Type 304 SS in an impurity environment with 0.25 ppM dissolved-oxygen; however, the latter material stops cracking when sulfate is removed from the water. Crack growth in both materials ceases under simulated hydrogen-water chemistry conditions (<5 ppB oxygen) even with 100 ppB sulfate present in the water. An unexpected result was obtained in the test on a weld overlay specimen in the impurity environment, viz., the crack …
Date: October 1, 1986
Creator: Shack, W.J.; Kassner, T.F.; Maiya, P.S.; Park, J.Y. & Ruther, W.E.
Object Type: Article
System: The UNT Digital Library
Calculated photon KERMA factors based on the LLNL EGDL (Evaluated Gamma-Ray Data Library) data file (open access)

Calculated photon KERMA factors based on the LLNL EGDL (Evaluated Gamma-Ray Data Library) data file

Photon (Gamma-Ray) KERMA factors calculated from the LLNL EGDL (Evaluated Gamma-Ray Data Library) file are tabulated for the elements from Z=1 to Z=30 and for 15 composite materials. The KERMA factors are presented for 191 energy groups over the incident photon energy range from 100 eV to 100 MeV. 3 refs.
Date: October 10, 1986
Creator: Howerton, Robert J.
Object Type: Report
System: The UNT Digital Library
Calculation of electromagnetic observables in few-body systems (open access)

Calculation of electromagnetic observables in few-body systems

An introduction to the calculation of electromagnetic observables in few-body systems is given by studying two examples in the trinucleon system: (1) the elastic electron scattering charge form factor in configuration space and momentum space and (2) the two-body photodisintegration of /sup 3/H leading to a neutron-deuteron final state in a separable potential formalism. In the discussion of charge form factor calculations, a number of related topics are touched upon: the relation of structure in Psi to the properties of simple NN forces, the Faddeev and Schroedinger solution to the harmonic oscillator problem, the Rosenbluth formula for electron scattering from a spin-1/2 nuclear target (e.g., the proton or /sup 3/H), and the charge density operator. Formulae for /sup 3/He and /sup 3/H charge form factors in a central force approximation are given in configuration and momentum space. The physics of these form factors is discussed in light of results from realistic nucleon-nucleon potential model calculations, including the effects of two-pion-exchange three-body force models. Topics covered are the rms charge densities, and the Coulomb energy of /sup 3/He. In the discussion of the /sup 3/H photodisintegration, the Siegert form of the electric dipole operator (in the long wave length limit) is …
Date: October 1, 1986
Creator: Gibson, B. F.
Object Type: Report
System: The UNT Digital Library
O(. cap alpha. /sup 2/)W mass shift from a very heavy top quark (open access)

O(. cap alpha. /sup 2/)W mass shift from a very heavy top quark

Oblique correction contributions to the W mass involving the various vacuum polarizations in a renormalization scheme independent way has been done starting from a general approach which evaluates higher order corrections. The specific case of the heavy top corrections on the order of ..cap alpha../sup 2/ to the precise W mass is considered. It is concluded that effects on the order of ..cap alpha../sup 2/ are negligible even at a level of accuracy of 50 MeV. 7 refs. (LEW)
Date: October 1, 1986
Creator: Lynn, B. W.; Kennedy, D. & Verzegnassi, C.
Object Type: Article
System: The UNT Digital Library