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A comparative study of short range order in Fe-Cr and Fe-V alloys around equiatomic composition (open access)

A comparative study of short range order in Fe-Cr and Fe-V alloys around equiatomic composition

Configurational energies have been calculated for equiatomic Fe-Cr and Fe-V alloys possessing the high temperature bcc crystalline structure, within a first principles electronic band structure approach. In agreement with experimental facts, a tendency towards order, with a B2 ordered structure of CsCl type, is found for FeV whereas phase separation characterized FeCr. These results suggest that the nature of short range order in the high temperature bcc solid solution is not the primary driving force for describing the structural transformation from bcc to sigma which takes place in both alloys upon decreasing temperature. 15 refs., 9 figs., 1 tab.
Date: December 4, 1990
Creator: Turchi, P.E.A.; Sluiter, M. (Lawrence Livermore National Lab., CA (USA)) & Stocks, G.M. (Oak Ridge National Lab., TN (USA))
System: The UNT Digital Library
Emission assessment from full-scale co-combustion tests of binder- enhanced dRDF pellets and high sulfur coal at Argonne National Laboratory (open access)

Emission assessment from full-scale co-combustion tests of binder- enhanced dRDF pellets and high sulfur coal at Argonne National Laboratory

Argonne National Laboratory (ANL) and University of North Texas (UNT) research teams collected over 800 emissions and ash samples during the combustion of over 650 tons of binder enhanced densified refuse-drived fuel (b-dRDF) pellets with high sulfur coal in a spreader-stoker boiler at ANL. This full-scale test burn was conducted to validate predictions from laboratory and pilot scale test results that indicated substantial reductions of SO{sub 2}, NO{sub x} and CO{sub 2} in the flue gas, and the reduction of heavy metals and organics in the ash residue, when combusting the b-dRDF pellets with coal. Effects of varying fuel composition on performance of the boiler's spray-dryer/fabric filter emissions control system was also evaluated. This paper describes the b-dRDF pellet/coal cofiring tests, the emission and ash samples that were taken, the analyses that were conducted on these samples, and the final test results. 5 refs., 1 fig., 1 tab.
Date: June 4, 1990
Creator: Ohlsson, O. O.; Livengood, C. D. (Argonne National Lab., IL (USA)) & Daugherty, K. E. (University of North Texas, Denton, TX (USA))
System: The UNT Digital Library
Grazing incidence metal mirrors as the final elements in a laser driver for inertial confinement fusion (open access)

Grazing incidence metal mirrors as the final elements in a laser driver for inertial confinement fusion

Grazing incidence metal mirrors (GIMMS) have been examined to replace dielectric mirrors for the final elements in a laser beam line for an inertial confinement fusion (ICF) reactor. For a laser driver using light with a wavelength from 250 to 500 nm in a 10 ns pulse, irradiated mirrors made of Al, Al alloys, or Mg were found to have calculated laser damage limits of 0.3--2.3 J/cm{sup 2} of beam energy and neutron lifetime fluence limits of over 5 {times} 10{sup 20} neutrons per square centimeter when use at grazing incidence (an angle of incidence of 85 degrees) and operated at room temperature or at 77 K. A final focusing system including mirrors made of Al alloy 7475 at room temperature or at liquid nitrogen (LN) temperatures used with a driver which delivers 5 MJ of beam energy in 32 beams would require 32 mirrors of roughly 10 m{sup 2} each. This paper briefly reviews the methods used in calculating the damage limits for GIMMs and discusses critical issues relevant to the integrity and lifetime of such mirrors in a reactor environment. 9 refs.
Date: October 4, 1990
Creator: Bieri, R. L. & Guinan, M. W.
System: The UNT Digital Library
Parametric cost analysis of a HYLIFE-II power plant (open access)

Parametric cost analysis of a HYLIFE-II power plant

The SAFIRE (Systems Analysis for ICF Reactor Economics) code was adapted to model a power plant using a HYLIFE-II reactor chamber. The code was then used to examine the dependence of the plant capital costs and busbar cost of electricity (COE) on a variety of design parameters (type of driver, chamber repetition rate, and net electric power). The results show the most attractive operating space for each set of driver/target assumptions and quantify the benefits of improvements in key design parameters. The base case plant was a 1,000 MWe plant containing a reactor vessel driven by an induction linac heavy ion accelerator run at 7.3 Hz with a driver energy of 5 MJ and a target yield of 370 MJ. The total direct cost for this plant was 2,800 M$ (where all $ in this paper are 1988$s), and the COE was 9 {cents}/KW*hour. The COE and total capital costs for the base plant assumptions for a 1,000 MWe plant are approximately independent of chosen repetition rate for all repetition rates between 4 and 10 Hz. For comparison, the COE for a coal or future fission plant would be 4.5--5.5 {cents}/KW*hour. The COE for a 1,000 MWe plant could be …
Date: October 4, 1990
Creator: Bieri, R.L. (Lawrence Livermore National Lab., CA (USA) Massachusetts Inst. of Tech., Cambridge, MA (USA))
System: The UNT Digital Library
Wake potentials and impedances for the ATA (Advanced Test Accelerator) induction cell (open access)

Wake potentials and impedances for the ATA (Advanced Test Accelerator) induction cell

The AMOS Wakefield Code is used to calculate the impedances of the induction cell used in the Advanced Test Accelerator (ATA) at Livermore. We present the wakefields and impedances for multipoles m = 0, 1 and 2. The ATA cell is calculated to have a maximum transverse impedance of approximately 1000 {Omega}/m at 875 MHz with a quality factor Q = 5. The sensitivity of the impedance spectra to modeling variations is discussed.
Date: September 4, 1990
Creator: Craig, George D.
System: The UNT Digital Library
Laser driven instabilities in inertial confinement fusion (open access)

Laser driven instabilities in inertial confinement fusion

Parametric instabilities excited by an intense electromagnetic wave in a plasma is a fundamental topic relevant to many applications. These applications include laser fusion, heating of magnetically-confined plasmas, ionospheric modification, and even particle acceleration for high energy physics. In laser fusion, these instabilities have proven to play an essential role in the choice of laser wavelength. Characterization and control of the instabilities is an ongoing priority in laser plasma experiments. Recent progress and some important trends will be discussed. 8 figs.
Date: June 4, 1990
Creator: Kruer, W.L.
System: The UNT Digital Library
Reduction of Beam Corkscrew Motion on the ETAII Linear Induction Accelerator (open access)

Reduction of Beam Corkscrew Motion on the ETAII Linear Induction Accelerator

The ETAII linear induction accelerator (6MeV, 3kA, 70ns) is designed to drive a microwave free electron laser (FEL) and demonstrate the front end accelerator technology for a shorter wavelength FEL. Performance to date has been limited by beam corkscrew motion that is driven by energy sweep and misalignment of the solenoidal focusing magnets. Modifications to the pulse power distribution system and magnetic alignment are expected to reduce the radius of corkscrew motion from its present value of 1 cm to less than 1 mm. The modifications have so far been carried out on the first 2.7 MeV (injector plus 20 accelerator cells) and experiments are beginning. In this paper we will present calculations of central flux line alignment, beam corkscrew motion and beam brightness that are anticipated with the modified ETAII. 10 refs., 4 figs., 1 tab.
Date: September 4, 1990
Creator: Turner, W. C.; Allen, S. L.; Brand, H. R.; Caporaso, G. J.; Chambers, F. W.; Chen, Y. J. et al.
System: The UNT Digital Library
Dielectronic recombination measurements at EBIT (Electron Beam Ion Trap) (open access)

Dielectronic recombination measurements at EBIT (Electron Beam Ion Trap)

The Electron Beam Ion Trap at the Lawrence Livermore National Laboratory has proved an ideal device for the study of interactions between electrons and highly-charged ions. I describe measurements of one such interaction, dielectronic recombination, in several ion species. The results are in marginal agreement with theoretical predictions. 8 refs., 6 figs.
Date: October 4, 1990
Creator: Knapp, D.A.
System: The UNT Digital Library
Novel plasma-based frequency upshift methods for short pulse lasers (open access)

Novel plasma-based frequency upshift methods for short pulse lasers

We discuss various novel methods of frequency upshifting short ({le} 1 picosecond) pulses of laser light. All of these methods make use of either the sudden creation of a plasma or relativistic plasma waves. The first method discussed is known as photon acceleration. This method makes use of the fact that a laser pulse moving in a plasma can be thought of as a packet of photons, each possessing an effective mass of m{sub {gamma}} = {h bar}{omega}{sub pe}/c{sup 2} and moving with the group velocity of the laser pulse. These photons experience a force acting on them when in the presence of a gradient in the plasma density. By using a relativistic plasma wave (i.e., a moving density gradient) traveling with the photons, the energy of the photons (thus the frequency) can be continuously increased. We then discuss the sudden creation of a plasma in a region where there exists an electromagnetic wave. This results in a frequency shift of the wave. A similar method is the creation of an ionization front moving near the speed of light, whereby the interaction of this plasma front with an EM wave also results in a frequency upshift of the original wave. …
Date: June 4, 1990
Creator: Wilks, S.C. (Lawrence Livermore National Lab., CA (USA)); Dawson, J.M. & Mori, W.B. (California Univ., Los Angeles, CA (USA). Dept. of Physics)
System: The UNT Digital Library
Status Report on Fermilab Experiment E-760: A Study of Charmonium Produced by Proton-Antiproton Annihilation (open access)

Status Report on Fermilab Experiment E-760: A Study of Charmonium Produced by Proton-Antiproton Annihilation

This was a status report on Fermilab experiment E-760 -- an experiment to study charmonium states by resonant formation in proton-antiproton annihilation. The experiment uses antiprotons circulating in the Fermilab antiproton-accumulator as the beam and an internal hydrogen gas-jet as the target. Data taking with the full complement of apparatus started in early July 1990.
Date: September 4, 1990
Creator: Pordes, Stephen
System: The UNT Digital Library
Oscillating liquid flow ICF (inertial confinement fusion) reactor (open access)

Oscillating liquid flow ICF (inertial confinement fusion) reactor

Oscillating liquid flow in a falling molten salt inertial confinement fusion reactor is predicted to rapidly clear driver beam paths of residual molten salt. Oscillating flow will also provide adequate neutron and x-ray protection for the reactor structure with a short (2-m) fall distance permitting an 8 Hz repetition rate. A reactor chamber configuration is presented with specific features to clear the entire heavy-ion beam path of splashed molten salt. The structural components, including the structure between beam ports, are shielded. 3 refs., 12 figs.
Date: October 4, 1990
Creator: Petzoldt, R.W.
System: The UNT Digital Library
Chemical kinetic modeling of chlorinated hydrocarbons under stirred-reactor conditions (open access)

Chemical kinetic modeling of chlorinated hydrocarbons under stirred-reactor conditions

The combustin of chloroethane is modeled as a stirred reactor so that we can study critical emission characteristics of the reactor as a function of residence time. We examine important operating conditions such as pressure, temperature, and equivalence ratio and their influence on destructive efficiency of chloroethane and production of other chlorinated products. The model uses a detailed chemical kinetic mechanism that we have developed previously for C{sub 3} hydrocarbons. We have added to this mechanism the chemical kinetic mechanism for C{sub 2} chlorinated hydrocarbons developed by Senkan and coworkers. Some reactions have been added to Senkan's mechanism and some of the reaction-rate expressions have been updated to reflect recent developments in the literature. In the modeling calculations, sensitivity coefficients are determined to find which reaction-rate constants have the largest effect on destructive efficiency. 25 refs., 6 figs., 1 tab.
Date: October 4, 1990
Creator: Pitz, W.J. & Westbrook, C.K.
System: The UNT Digital Library
HYLIFE-2 inertial confinement fusion reactor design (open access)

HYLIFE-2 inertial confinement fusion reactor design

The HYLIFE-II inertial fusion power plant design study uses a liquid fall, in the form of jets to protect the first structural wall from neutron damage, x-rays, and blast to provide a 30-y lifetime. HYLIFE-I used liquid lithium. HYLIFE-II avoids the fire hazard of lithium by using a molten salt composed of fluorine, lithium, and beryllium (Li{sub 2}BeF{sub 4}) called Flibe. Access for heavy-ion beams is provided. Calculations for assumed heavy-ion beam performance show a nominal gain of 70 at 5 MJ producing 350 MJ, about 5.2 times less yield than the 1.8 GJ from a driver energy of 4.5 MJ with gain of 400 for HYLIFE-I. The nominal 1 GWe of power can be maintained by increasing the repetition rate by a factor of about 5.2, from 1.5 to 8 Hz. A higher repetition rate requires faster re-establishment of the jets after a shot, which can be accomplished in part by decreasing the jet fall height and increasing the jet flow velocity. Multiple chambers may be required. In addition, although not considered for HYLIFE-I, there is undoubtedly liquid splash that must be forcibly cleared because gravity is too slow, especially at high repetition rates. Splash removal can be accomplished …
Date: October 4, 1990
Creator: Moir, Ralph W.
System: The UNT Digital Library
Soft x-ray detection with diamond photoconductive detectors (open access)

Soft x-ray detection with diamond photoconductive detectors

Photoconductive detectors fabricated from natural lla diamonds have been used to measure the x-ray power emitted from laser produced plasmas. The detector was operated without any absorbing filters to distort the x-ray power measurement. The 5.5 eV bandgap of the detector material practically eliminates its sensitivity to scattered laser radiation thus permitting filterless operation. The detector response time or carrier life time was 90 ps. Excellent agreement was achieved between a diamond PCD and a multichannel photoemissive diode array in the measurement of radiated x-ray power and energy. 4 figs.
Date: May 4, 1990
Creator: Kania, D. R.; Pan, L.; Kornblum, H.; Bell, P.; Landen, O. N. & Pianetta, P.
System: The UNT Digital Library
Fermilab Library Directions (open access)

Fermilab Library Directions

In this document, we indicate our current thinking about the directions of the Fermilab Library. The ideas relate to the preprint management issue in a number of ways. The ideas are subject to revision as we come to understand what is possible as well as what is needed by the Laboratory community. This document should therefore be regarded as our personal view--the availability of off-the-shelf technology, of funding as well as feedback from the laboratory community about their needs will all affect how far we actually proceed in any of these directions.
Date: May 4, 1990
Creator: Garrett, P. & Ritchie, D.
System: The UNT Digital Library
Stark-effect measurement of high FEL (free-electron laser) electric fields in MTX (Microwave Tokamak Experiment) by laser-aided particle-probe spectroscopy (open access)

Stark-effect measurement of high FEL (free-electron laser) electric fields in MTX (Microwave Tokamak Experiment) by laser-aided particle-probe spectroscopy

We are constructing a diagnostic system to measure the electric field (>100 kV/cm) of a free-electron laser (FEL) beam when injected into the plasma of the Microwave Tokamak Experiment (MTX). The apparatus allows a crossed-beam measurement, with 2-cm spatial resolution in the plasma, involving the FEL beam (with 140-GHz, {approx}1-GW ECH pulses), a neutral-helium beam, and a dye-laser beam. After the laser beam pumps metastable helium atoms to higher excited states, their decay light is detected by a collimated optical system. Because of the Stark effect due to the FEL electric field ({rvec E}), a forbidden transition can be strongly induced. The intensity of emitted light resulting from the forbidden transition is proportional to E{sup 2}. Because photon counting rates are calculated to be low, extra effort is made to minimize background and noise levels. It is possible that the lower {rvec E} of an MTX gyrotron-produced ECH beam with its longer-duration pulses also can be measured using this method. Other applications may include measurements of ion temperature (using charge-exchange recombination), edge-density fluctuations, and core impurity concentrations. 11 refs., 2 figs., 2 tabs.
Date: May 4, 1990
Creator: Oda, T.; Takiyama, K.; Odajima, K.; Ohasa, K.; Shiho, M.; Mizuno, K. et al.
System: The UNT Digital Library
Thomson scattering diagnostic for the Microwave Tokamak Experiment (open access)

Thomson scattering diagnostic for the Microwave Tokamak Experiment

The Thomson-scattering diagnostic system (TSS) on the Microwave Tokamak Experiment (MTX) at LLNL routinely monitors electron temperature (T{sub e}) and density. Typical measured values at the plasma center under clean conditions are 900 {plus minus} 70 eV and 1 to 2 {times} 10{sup 14} ({plus minus}30%) cm{sup {minus}3}. The TSS apparatus is compact, with all elements mounted on one sturdy, two-level optics table. Because of this, we maintain with minimum effort the alignment of both the ruby-laser input optics and the scattered-light collecting optics. Undesired background signals, e.g., plasma light as well as ruby-laser light scattered off obstacles and walls, are generally small compared with the Thomson-scattered signals we normally detect. In the MTX T{sub e} region, the TSS data are definitely fitted better when relativistic effects are included in the equations. Besides determining the temperature of the Maxwellian electron distribution, the system is designed to detect electron heating from GW-level free-electron laser (FEL) pulses by measuring large wavelength shifts of the scattered laser photons. TSS data suggest that we may indeed by able to detect these electrons, which can have energies up to 10 keV, according to computer simulation. 7 refs., 4 figs.
Date: May 4, 1990
Creator: Foote, J.H.; Barter, J.D.; Sewall, N.R.; Jolly, J.J. & Schlander, L.F.
System: The UNT Digital Library
Ion temperature analysis of implosions of DT-filled capsules (open access)

Ion temperature analysis of implosions of DT-filled capsules

Fuel ion temperatures have been deduced for a series of implosions of DT-filled capsules by measuring the thermally broadened neutron time-of-flight signals at 10 m and at 20 m from the target. Typical temperatures were around 1 keV, and the corresponding thermal broadening was comparable to or less than the time response of the detectors. Under these conditions, error minimization is crucial, and we find that the location of the detector and the analysis technique are important. An optimum location exits, but is very sensitive to the yield of the implosion and to the detector response. 5 refs., 3 figs.
Date: September 4, 1990
Creator: Remington, B. A.; Lerche, R. A. & Cable, M. D.
System: The UNT Digital Library
Detector distance selection for ICF temperature measurements by neutron TOF techniques (open access)

Detector distance selection for ICF temperature measurements by neutron TOF techniques

Fuel ion temperatures for laser-driven, inertial-confinement fusion targets are often determined by neutron time-of-flight (TOF) techniques. The error in the temperature measurement is a minimum at a target-to-detector distance that depends on both target and detector characteristics. The error is dominated by the detector response at shorter distances and by the number of detected neutrons at larger distances. We develop equations that relate the temperature error to the target ion temperature, the number of neutrons detected, target-to-detector distance, and the detector impulse response; and present sample calculations of the error for D-D and D-T plasmas observed by typical Nova neutron TOF detectors. The detector placement is important for minimizing temperature error for target yield below 10{sup 10} neutrons. 4 refs., 2 figs.
Date: September 4, 1990
Creator: Lerche, R. A. & Remington, B. A.
System: The UNT Digital Library