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Some frontiers of accelerator physics (open access)

Some frontiers of accelerator physics

This paper discusses some concepts of future accelerators such as free electron lasers, two beam accelerator; and plasma-based adiabatic compressor. 12 refs., 10 figs., 5 tabs. (LSP)
Date: October 13, 1989
Creator: Sessler, A. M.
System: The UNT Digital Library
MPS II drift-chamber system (open access)

MPS II drift-chamber system

A new system of detectors (MPS II) which has been installed and operated in the Brookhaven National Laboratory Multiparticle Spectrometer (MPS), consisting of short drift distance drift chambers is briefly described. (WHK)
Date: May 13, 1982
Creator: Etkin, A.; Eiseman, S. & Foley, K.J.
System: The UNT Digital Library
Energy calibration scheme for acoustic emission (open access)

Energy calibration scheme for acoustic emission

The calibration technique described is an attempt to determine the actual energy release from the events causing emission bursts in beryllium and to quantitatively evaluate the effects of specimen geometry on the apparent energy per burst. (GHT)
Date: September 13, 1977
Creator: Adams, R. O. & Heiple, C. R.
System: The UNT Digital Library
A fast large-area position-sensitive time-of-flight neutron detection system (open access)

A fast large-area position-sensitive time-of-flight neutron detection system

A new position-sensitive time-of-flight neutron detection and histograming system has been developed for use at the Intense Pulsed Neutron Source. Spatial resolution of roughly 1 cm {times} 1 cm and time-of-flight resolution of {approximately}1 {mu}sec are combined in a detection system which can ultimately be expanded to cover several square meters of active detector area. This system is based on the use of arrays of cylindrical one-dimensional position-sensitive proportional counters, and is capable of collecting the x-y-t data and sorting them into histograms at time-averaged data rates up to {approximately}300,000 events/sec over the full detector area and with instantaneous data rates up to more than fifty times that. Numerous hardware features have been incorporated to facilitate initial tuning of the position encoding, absolute calibration of the encoded positions, and automatic testing for drifts. 7 refs., 11 figs., 1 tabs.
Date: October 13, 1989
Creator: Crawford, R.K. & Haumann, J.R.
System: The UNT Digital Library
Review of free electron laser theory and experiments (open access)

Review of free electron laser theory and experiments

A review of the major Free Electron Laser (FEL) experiments will be presented. These experiments are designed to produce radiation at wavelengths from the far infrared to the ultraviolet. Different categories of FELs (Compton, Raman, optical klystron, two stage, etc.), as well as the suitability of various types of electron accelerators to power FELs, will also be discussed. Potential applications of the FEL will be summarized.
Date: January 13, 1984
Creator: Prosnitz, D.
System: The UNT Digital Library
Electromagnetic Effects in Relativistic Electron Beam Plasma Interactions (open access)

Electromagnetic Effects in Relativistic Electron Beam Plasma Interactions

Electromagnetic effects excited by intense relativistic electron beams in plasmas are investigated using a two-dimensional particle code. The simulations with dense beams show large magnetic fields excited by the Weibel instability as well as sizeable electromagnetic radiation over a significant range of frequencies. The possible relevance of beam plasma instabilities to the laser acceleration of particles is briefly discussed. 6 refs., 4 figs.
Date: February 13, 1985
Creator: Kruer, W. L. & Langdon, A. B.
System: The UNT Digital Library
ITER disruption modeling using TSC (Tokamak Simulation Code) (open access)

ITER disruption modeling using TSC (Tokamak Simulation Code)

Design of the ITER vacuum vessel (VV) is driven strongly by disruption-induced forces. We use the Tokamak Simulation Code (TSC) to model disruptions for the ITER physics phase (I{sub p} = 22 MA) and predict the time evolution of currents and forces on the VV. For a plasma vertically displaced to Z{sub axis} = {minus}1.0m before disruption and decaying at a rate of < dI{sub p}/dt > {approx equal} {minus}1.0MA/ms, the induced VV current peaks at 18 MA. The maximum radial VV force F{sub R} is 56 MN/rad; the maximum vertical force F{sub Z} is 5.4 MN/rad; and the maximum VV disruption pressure is 1.0 MPa. Variations in VV resistance (20 - 160 {mu}{Omega}) and < dI{sub p}/dt > (1 - 2.5 MA/ms) do not change F{sub R} significantly. The dependence of the forces on the initial plasma displacement and < dI{sub p}/dt > behavior, and the responses of other conducting structures are discussed. 2 refs., 6 figs.
Date: November 13, 1989
Creator: Sayer, R. O.; Peng, Y. K. M.; Wesley, J. C.; Jardin, S. C. (Oak Ridge National Lab., TN (USA); General Atomics, San Diego, CA (USA) & Princeton Univ., NJ (USA). Plasma Physics Lab.)
System: The UNT Digital Library
L-shell photoabsorption spectroscopy for solid metals: Ti, V, Cr, Fe, Ni, Cu (open access)

L-shell photoabsorption spectroscopy for solid metals: Ti, V, Cr, Fe, Ni, Cu

Synchrotron radiation measurements of near-threshold and broad-range (400--1500 eV) absolute photoabsorption cross sections were made for five transition metals with {plus minus}10% overall uncertainties. Fine structure details of 2p-3d autoionizing resonances are shown with better than 1.0 eV resolution for solid metals: Ti, V, Cr, Fe, Ni, and Cu. Fine structure similar to what we measured can be produced using a multi-configuration Dirac Fock (MCDF) model if a statistical distribution is assumed for the initial atomic states. Calculations were performed in intermediate coupling with configuration interactions by Mau H. Chen. The results are compared with other experimental work and theoretical methodologies. 18 refs., 7 figs.
Date: September 13, 1989
Creator: Del Grande, N.K. (Lawrence Livermore National Lab., CA (USA))
System: The UNT Digital Library
Clinch River breeder reactor sodium fire protection system design and development (open access)

Clinch River breeder reactor sodium fire protection system design and development

To assure the protection of the public and plant equipment, improbable accidents were hypothesized to form the basis for the design of safety systems. One such accident is the postulated failure of the Intermediate Heat Transfer System (IHTS) piping within the Steam Generator Building (SGB), resulting in a large-scale sodium fire. This paper discusses the design and development of plant features to reduce the consequences of the accident to acceptable levels. Additional design solutions were made to mitigate the sodium spray contribution to the accident scenario. Sodium spill tests demonstrated that large sodium leaks can be safely controlled in a sodium-cooled nuclear power plant.
Date: April 13, 1984
Creator: Foster, K.W.; Boasso, C.J. & Kaushal, N.N.
System: The UNT Digital Library
Initial measurements of beam breakup instability in the advanced test accelerator (open access)

Initial measurements of beam breakup instability in the advanced test accelerator

This paper reports the measurements of beam breakup (BBU) instability performed on the Advanced Test Accelerator (ATA) up to the end of February, 1984. The main objective was to produce a high current usable electron beam at the ATA output. A well-known instability is BBU which arises from the accelerator cavity modes interacting with the electron beam. The dominant mode is TM/sub 130/ at a frequency of approximately 785 MHz. It couples most strongly to the beam motion and has been observed to grow in the Experimental Test Accelerator (ETA) which has only eight accelerator cavities. ATA has one hundred and seventy cavities and, therefore, the growth of BBU is expected to be more severe. In this paper, BBU measurements are reported for ATA with beam currents of 4 to 7 kA. Analysis showed that the growth of the instability with propagation distance was as expected for the lower currents. However, the high-current data showed an apparent higher growth rate than expected. An explanation for this anomaly is given in terms of a ''corkscrew'' excitation. The injector BBU noise level for a field emission brush cathode was found to be an order of magnitude lower than for a cold plasma …
Date: May 13, 1985
Creator: Chong, Y.P.; Caporaso, G.J. & Struve, K.W.
System: The UNT Digital Library
Two gauge boson physics at future colliders (open access)

Two gauge boson physics at future colliders

Electroweak unification suggests that there should be WW and ZZ physics analogous to {gamma}{gamma} physics. Indeed, WW and ZZ collisions will provide an opportunity to search for the Higgs boson at future high energy colliders. Cross sections in the picobarn range are predicted for Higgs boson production at the proposed 40-TeV SSC. While other states may be produced by WW and ZZ collisions, it is the Higgs boson that looms as the most attractive objective. 31 refs., 5 figs.
Date: May 13, 1988
Creator: Cahn, Robert N.
System: The UNT Digital Library
Molten salt processing of mixed wastes with offgas condensation (open access)

Molten salt processing of mixed wastes with offgas condensation

We are developing an advanced process for treatment of mixed wastes in molten salt media at temperatures of 700--1000{degrees}C. Waste destruction has been demonstrated in a single stage oxidation process, with destruction efficiencies above 99.9999% for many waste categories. The molten salt provides a heat transfer medium, prevents thermal surges, and functions as an in situ scrubber to transform the acid-gas forming components of the waste into neutral salts and immobilizes potentially fugitive materials by a combination of particle wetting, encapsulation and chemical dissolution and solvation. Because the offgas is collected and assayed before release, and wastes containing toxic and radioactive materials are treated while immobilized in a condensed phase, the process avoids the problems sometimes associated with incineration processes. We are studying a potentially improved modification of this process, which treats oxidizable wastes in two stages: pyrolysis followed by catalyzed molten salt oxidation of the pyrolysis gases at ca. 700{degrees}C. 15 refs., 5 figs., 1 tab.
Date: May 13, 1991
Creator: Cooper, J.F.; Brummond, W.; Celeste, J.; Farmer, J.; Hoenig, C.; Krikorian, O.H. et al.
System: The UNT Digital Library
Miniature specimen technology for postirradiation fatigue crack growth testing (open access)

Miniature specimen technology for postirradiation fatigue crack growth testing

Current magnetic fusion reactor design concepts require that the fatigue behavior of candidate first wall materials be characterized. Fatigue crack growth may, in fact, be the design limiting factor in these cyclic reactor concepts given the inevitable presence of crack-like flaws in fabricated sheet structures. Miniature specimen technology has been developed to provide the large data base necessary to characterize irradiation effects on the fatigue crack growth behavior. An electrical potential method of measuring crack growth rates is employed on miniature center-cracked-tension specimens (1.27 cm x 2.54 cm x 0.061 cm). Results of a baseline study on 20% cold-worked 316 stainless steel, which was tested in an in-cell prototypic fatigue machine, are presented. The miniature fatigue machine is designed for low cost, on-line, real time testing of irradiated fusion candidate alloys. It will enable large scale characterization and development of candidate first wall alloys.
Date: November 13, 1979
Creator: Mervyn, D.A. & Ermi, A.M.
System: The UNT Digital Library
Holdup measurement for nuclear fuel manufacturing plants (open access)

Holdup measurement for nuclear fuel manufacturing plants

The assay of nuclear material holdup in fuel manufacturing plants is a laborious but often necessary part of completing the material balance. A range of instruments, standards, and a methodology for assaying holdup has been developed. The objectives of holdup measurement are ascertaining the amount, distribution, and how firmly fixed the SNM is. The purposes are reconciliation of material unbalance during or after a manufacturing campaign or plant decommissioning, to decide security requirements, or whether further recovery efforts are justified.
Date: July 13, 1981
Creator: Zucker, M.S.; Degen, M.; Cohen, I.; Gody, A.; Summers, R.; Bisset, P. et al.
System: The UNT Digital Library
Use of AERIN code for determining internal doses of transuranic isotopes (open access)

Use of AERIN code for determining internal doses of transuranic isotopes

The AERIN computer code is a mathematical expression of the ICRP Lung Model. The code was developed at the Lawrence Livermore National Laboratory to compute the body organ burdens and absorbed radiation doses resulting from the inhalation of transuranic isotopes and to predict the amount of activity excreted in the urine and feces as a function of time. Over forty cases of internal exposure have been studied using the AERIN code. The code, as modified, has proven to be extremely versatile. The case studies presented demonstrate the excellent correlation that can be obtained between code predictions and observed bioassay data. In one case study a discrepancy was observed between an in vivo count of the whole body and the application of the code using urine and fecal data as input. The discrepancy was resolved by in vivo skull counts that showed the code had predicted the correct skeletal burden.
Date: June 13, 1980
Creator: King, W.C.
System: The UNT Digital Library
Materials evaluation for geothermal applications: turbine materials (open access)

Materials evaluation for geothermal applications: turbine materials

A number of candidate turbine materials are being evaluated for their resistance to erosion, corrosion, and stress corrosion cracking (SCC) in geothermal brines. These materials include Fe-, Ni-, Co and Ti-base alloys, coatings and ceramics. Tapered wearblades, simulating the leading edge of a turbine blade, are exposed to the direct impact of a two-phase nozzle exhaust. Bent beam SCC specimens, which are constrained in fixtures attached to the wearblade holders, are also exposed to this exhaust. Results of a test series are reported in which acidified liquid brine was expanded to atmospheric pressure are reported. The tests were performed at the LLL Field Test Station near Niland in the Salton Sea Geothermal Field. Evaluation of the exposed materials indicates that Ti-base alloys show the most promise for turbine wheel components in the high salinity geothermal environments.
Date: April 13, 1977
Creator: Goldberg, A. & Garrison, R.E.
System: The UNT Digital Library
Parameter studies of candidate lattices for the 1-2 GeV synchrotron radiation source (open access)

Parameter studies of candidate lattices for the 1-2 GeV synchrotron radiation source

This document discusses the implications of various collective phenomena on the required performance of candidate lattices for the LBL 1 to 2 GeV Synchrotron Radiation Source. The performance issues considered include bunch length, emittance growth, and beam lifetime. In addition, the possible use of the 1 to 2 GeV Synchrotron Radiation Source as a high-gain FEL is explored briefly. Generally, the differences between lattices are minor. It appears that the most significant feature distinguishing the various alternatives will be the beam lifetime.
Date: January 13, 1986
Creator: Zisman, M. S.
System: The UNT Digital Library
Perspectives in the theory of nuclear collective motion (open access)

Perspectives in the theory of nuclear collective motion

This report discusses three different subjects. The first is the development of a generalized version of the VMI (variable moment of inertia) model that ties it to the original form of the IBM (interacting boson model) and provides a possibility of fitting vibrational spectra with generalized vibrational formulas. The second is a suggestion for fitting band crossing calculations of the phenomenological type more completely than has hitherto been done into the framework of the VMI method. The third, which is the most important and far reaching, is the description f a complete mathematical method for the microscopic derivation of the IBM from a conventional shell-model Hamiltonian. In addition to elements already foreseen by previous authors, there is proposed a solution for the most important problem outstanding, not only within the framework of the IBM, but also in all previous work on boson expansion. This is the problem of actually selecting, in a general fashion, the most collective excitations. A criterion is introduced that the subspace constructed from these excitations should possess an average energy that is lower than the rest of the shell model space; the actual implementation of this criterion is explained. 8 tables, 62 references.
Date: March 13, 1980
Creator: Klein, A.
System: The UNT Digital Library
SEBREZ: an inertial-fusion-reactor concept (open access)

SEBREZ: an inertial-fusion-reactor concept

The neutronic aspects of an inertial fusion reactor concept that relies on asymmetrical neutronic effects to enhance the tritium production in the breeding zones have been studied. We find that it is possible to obtain a tritium breeding ratio greater than 1.0 with a chamber configuration in which the breeding zones subtend only a fraction of the total solid angle. This is the origin of the name SEBREZ which stands for SEgregated BREeding Zones. It should be emphasized that this is not a reactor design study; rather this study illustrates certain neutronic effects in the context of a particular reactor concept. An understanding of these effects forms the basis of a design technique which has broader application than just the SEBREZ concept.
Date: January 13, 1982
Creator: Meier, W. R.
System: The UNT Digital Library
Mirror Fusion Test Facility magnet (open access)

Mirror Fusion Test Facility magnet

The Mirror Fusion Test Facility (MFTF) is the largest of the mirror program experiments for magnetic fusion energy. It seeks to combine and extend the near-classical plasma confinement achieved in 2XIIB with the most advanced neutral-beam and magnet technologies. The product of ion density and confinement time will be improved more than an order of magnitude, while the superconducting magnet weight will be extrapolated from the 15 tons in Baseball II to 375 tons in MFTF. Recent reactor studies show that the MFTF will traverse much of the distance in magnet technology towards the reactor regime. Design specifics of the magnet are given. (MOW)
Date: November 13, 1979
Creator: Henning, C. H.; Hodges, A. J.; Van Sant, J. H.; Hinkle, R. E.; Horvath, J. A.; Hintz, R. E. et al.
System: The UNT Digital Library
Microwave Tokamak Experiment (MTX) ohmic heating system (open access)

Microwave Tokamak Experiment (MTX) ohmic heating system

The ohmic heating system for the Microwave Tokamak Experiment (MTX) at Lawrence Livermore National Laboratory (LLNL) provides both the voltage for the initial breakdown phase and the energy to drive the plasma current to a value of 400 kA or greater. Providing this voltage and flux swing requires a one-turn loop voltage of about 25 volts (11 kV across the coil) and a magnetic flux swing of 2 volt- seconds. This voltage and flux swing are accomplished by charging the ohmic heating coils to 20 kA, at which point the current is commutated off into a resistor generating the 11 kV across the coil. When the current passes through zero, another power supply drives the current in the opposite polarity to 20 kA, thus completing the full 2 volt-second flux swing. This paper describes the design features and performance of the ohmic heating circuit, with emphasis on the commutation circuit. In addition, the paper describes the use of the ohmic heating system for discharge cleaning and the changeover procedure. 3 refs., 4 figs., 1 tab.
Date: September 13, 1989
Creator: Jackson, M.C. (Lawrence Livermore National Lab., CA (USA))
System: The UNT Digital Library
Floating data acquisition system for microwave calorimeter measurements on MTX (open access)

Floating data acquisition system for microwave calorimeter measurements on MTX

A microwave calorimeter has been designed for making 140-GHz absorption measurements on the MTX. Measurement of the intensity and spatial distribution of the FEL-generated microwave beam on the inner wall will indicate the absorption characteristics of the plasma when heated with a 140 GHz FEL pulse. The calorimeter works by monitoring changes of temperature in silicon carbide tiles located on the inner wall of the tokamak. Thermistors are used to measure the temperature of each tile. The tiles are located inside the tokamak about 1 cm outside of the limiter radius at machine potential. The success of this measurement depends on our ability to float the data acquisition system near machine potential and isolate it from the rest of the vault ground system. Our data acquisition system has 48 channels of thermistor signal conditioning, a multiplexer and digitizer section, a serial data formatter, and a fiber-optic transmitter to send the data out. Additionally, we bring timing signals to the interface through optical fibers to tell it when to begin measurement, while maintaining isolation. The receiver is an HP 200 series computer with a serial data interface; the computer provides storage and local display for the shot temperature profile. Additionally, the …
Date: September 13, 1989
Creator: Sewall, N.R. & Meassick, S. (Lawrence Livermore National Lab., CA (USA))
System: The UNT Digital Library
Sensitivity and uncertainty investigations for Hiroshima dose estimates and the applicability of the Little Boy mockup measurements (open access)

Sensitivity and uncertainty investigations for Hiroshima dose estimates and the applicability of the Little Boy mockup measurements

This paper describes sources of uncertainty in the data used for calculating dose estimates for the Hiroshima explosion and details a methodology for systematically obtaining best estimates and reduced uncertainties for the radiation doses received. (ACR)
Date: September 13, 1983
Creator: Bartine, D. E. & Cacuci, D. G.
System: The UNT Digital Library
Textbooks Weighing you Down? Check out our E-Readers (open access)

Textbooks Weighing you Down? Check out our E-Readers

Article discussing a project by the UNT Libraries to purchase e-book readers for students purchasing digital textbooks.
Date: June 13, 2014
Creator: Brannon, Sian & Sears, Suzanne
System: The UNT Digital Library