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Studies of end loss from a theta pinch using a Twyman--Green interferometer. Scientific report 77-4

Description: The transient rate of flow of plasma from the ends of a short, high density, low temperature linear theta pinch was studied experimentally and analytically. Diagnostic devices were used to study the discharge and plasma properties; these included a Rogowski coil, a magnetic field probe and a Twyman-Green double pass interferometer which was illuminated by a 7 mW He--He laser. The interferometer was used to monitor the passage of fringes with respect to time at two radial positions simultaneously by the use of a photodetector consisting of two fast silicon photodiodes with supporting circuitry. One complete fringe represented a change in number density of 2.942 x 10/sup 16/ cm/sup -3/.
Date: November 1, 1977
Creator: Freeman, R.S.
Partner: UNT Libraries Government Documents Department

Air flow investigation for location of angle of attack head on a JN4h airplane

Description: The technical staff of the NACA at Langley Field, has made a series of free flight tests with a JN4h airplane in order to find the best place for an instrument for measuring the angle of attack. A "neutral zone" was found where the air remains either at rest relative to the undisturbed air beyond the influence of the airplane, or is set in motion parallel to the motion of the airplane. This zone is about midway between the two wings and slightly in front of, or at the vertical plane through the leading edges of the wings but the exact position as well as the outlines of the zone varies considerably as the conditions of flight change.
Date: August 1925
Creator: Freeman, R. G.
Partner: UNT Libraries Government Documents Department

Potential application of Madison formation waters for community heating in South Dakota

Description: It is suggested that the most practical early application of the Madison waters is in community space heating with the local hot waters considered as a municipal commodity. The general design of such a community system is discussed along with its cost, means of financing, and life expectancy. Legal questions and state statutes that are pertinent are cited and the life expectancy of the entire Madison resource and equipment to expoit the resource are considered. (MHR)
Date: September 1, 1978
Creator: Freeman, R.A. & Meier, R.F.
Partner: UNT Libraries Government Documents Department

Applications of high power millimeter waves in the DIII-D fusion program

Description: First operation of a new generation of MW level, 110 GHz generator (gyrotron) on the DIII-D fusion experimental device has been achieved. The desire for high power, cw millimeter (mm) wave sources to support fusion research and development is just now beginning to be realized. Plasma heating and current drive with directed mm waves rely on the strong absorption achieved when the wave frequency matches the natural ``cyclotron`` frequency of electrons in a magnetic field, or its harmonics. Recent progress in fusion experiments highlights the need for control of the interior details of the hot plasma, and nun wave systems are ideally suited for this role. A brief status of fusion research is given, and the importance of mm waves in the future directions for fusion research is described. The vacuum transmission components necessary for transmitting, monitoring, and launching high power 1 10 GHz waves into a plasma have been developed at General Atomics (GA) and will be described. High power mm waves have a number of attractive technological features for fusion applications compared with other candidate plasma heating and current drive technologies. Millimeter waves can be transmitted with high power density over large distances with low losses by utilizing corrugated waveguides, so the generators can be sited remotely, facilitating maintenance and saving valuable space near the fusion device.
Date: August 1, 1996
Creator: Freeman, R.L.
Partner: UNT Libraries Government Documents Department

Lower hybrid wave electron heating experiments in Doublet IIA

Description: Experiments designed to heat electrons by Landau damping of waves at approximately twice the lower hybrid frequency have been carried out on Doublet IIA. This objective is in contrast to other lower hybrid experiments which are designed to heat ions using frequencies corresponding to the lower hybrid resonance frequency. Up to 500 kW of rf power was applied to discharge with approximately 100 kW ohmic input using parallel wavelengths chosen to optimize the spatial distribution of the power deposition based on linear or quasi-linear Landau damping.
Date: July 1, 1980
Creator: Freeman, R.L.; Luxon, J.L. & Chan, V.S.
Partner: UNT Libraries Government Documents Department

Comparative evaluation of radon measurement techniques for uranium exploration. National Uranium Resource Evaluation

Description: The measurement of radon (Rn-222) in soil gas aids in uranium exploration by indicating indirectly the presence of buried ore bodies. Intrest in this exploration methodology has led to the development of various radon measurement techniques which detect the presence of soil-gas radon, both directly and/or indirectly. To establish the relative merit of these new radon measurement techniques, Bendix Field Engineering Corporation has tested a variety of them using existing uranium occurrences located in the Red Desert area of south-central Wyoming. The following soil-gas radon measurement techniques were tested: a prototype microprocessor-controlled emanometer; a commercially available emanometer; alpha-track detectors equipped with two types of detector material (carbonate and nitrate), and equipped with and without membranes for thoron separation; radon adsorption on activated charcoal; and partial extraction of lead-210 from soil samples. These techniques were compared for relative sensitivity, variability, signal-to-background contrast, and correlation. The radon measurements obtained were also correlated to the equivalent uranium in soil, as determined radiometrically. From approximately 34 replicate samples, the variability associated with a technique was lowest with the TSA emanometer (13%). The EDA emanometer showed 31% and Track Etch carbonate/open cup (C/O) 27%. The best signal-to-background ratio, 2.55, was obtained by the EDA emanometer; the Track Etch nitrate/members cup (N/M) was a close second with 2.45. All signal-to-background ratios were greater than 2.0 except for the TSA emanometer with 1.87. All the techniques measured a sufficient number of anomalous values to locate the subsurface ore body.
Date: March 1, 1983
Creator: Czarnecki, R F; Pacer, J C & Freeman, R W
Partner: UNT Libraries Government Documents Department

Fusion applications of high power millimeter wave sources

Description: Heating by means of high power electron cyclotron (EC) waves in the mm wavelength range is considered to be one of the most attractive approaches for heating fusion plasmas to the temperatures required to achieve ignition. EC waves have also been used to drive plasma current by using directional launch and to stabilize MHD instabilities in tokamak plasmas through localized heating or current drive. Experiments are planned on both JET and TFTR to measure the alpha particle distribution by scattering EC waves.
Date: January 1, 1994
Creator: Freeman, R. L. & George, T. V.
Partner: UNT Libraries Government Documents Department

Design of an RF Antenna for a Large0Bore, High Power, Steady State Plasma Processing Chamber for Material Separation

Description: The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC, (Contractor), and Archimedes Technology Group, (Participant) is to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure. The project objectives are to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure.
Date: November 7, 2001
Creator: Rasmussen, D.A. & Freeman, R.L.
Partner: UNT Libraries Government Documents Department

Determination of turning characteristics of an airship by means of a camera obscura

Description: This investigation was carried out by the National Advisory Committee at Langley Field for the purpose of determining the adaptability of the camera obscura to the securing of turning characteristics of airships, and also of obtaining some of those characteristics of the C-7 airship. The method consisted in flying the airship in circling flight over a camera obscura and photographing it at known time intervals. The results show that the method used is highly satisfactory and that for the particular maneuver employed the turning diameter is 1,240 feet, corresponding to a turning coefficient of 6.4, and that the position of zero angle of yaw is at the nose of the airship.
Date: 1925
Creator: Crowley, J. W., Jr. & Freeman, R. G.
Partner: UNT Libraries Government Documents Department

Application of Archimedes Filter for Reduction of Hanford HLW

Description: Archimedes Technology Group, Inc., is developing a plasma mass separator called the Archimedes Filter that separates waste oxide mixtures ion by ion into two mass groups: light and heavy. For the first time, it is feasible to separate large amounts of material atom by atom in a single pass device. Although vacuum ion based electromagnetic separations have been around for many decades, they have traditionally depended on ion beam manipulation. Neutral plasma devices, on the other hand, are much easier, less costly, and permit several orders of magnitude greater throughput. The Filter has many potential applications in areas where separation of species is otherwise difficult or expensive. In particular, radioactive waste sludges at Hanford have been a particularly difficult issue for pretreatment and immobilization. Over 75% of Hanford HLW oxide mass (excluding water, carbon, and nitrogen) has mass less than 59 g/mol. On the other hand, 99.9% of radionuclide activity has mass greater than 89 g/mol. Therefore, Filter mass separation tuned to this cutoff would have a dramatic effect on the amount of IHLW produced--in fact IHLW would be reduced by a factor of at least four. The Archimedes Filter is a brand new tool for the separations specialist's toolbox. In this paper, we show results that describe the extent to which the Filter separates ionized material. Such results provide estimates for the potential advantages of Filter tunability, both in cutoff mass (electric and magnetic fields) and in degree of ionization (plasma power). Archimedes is now engaged in design and fabrication of its Demonstration Filter separator and intends on performing a full-scale treatment of Hanford high-level waste surrogates. The status of the Demo project will be described.
Date: February 26, 2002
Creator: Gilleland, J.; Agnew, S.; Cluggish, B.; Freeman, R.; Miller, R.; Putvinski, S. et al.
Partner: UNT Libraries Government Documents Department

/sup 18/O + /sup 12/C fusion-evaporation reaction

Description: A study of the /sup 18/O + /sup 12/C fusion evaporation reaction has been undertaken for 2 reasons: to make a systematic study of the formation cross section for each individual evaporation residue over a broad excitation energy region in the compound nucleus /sup 30/Si:30 to 62 MeV; and to compare all results to fusion-evaporation calculations done in the framework of the Hauser-Feschbach statistical model.
Date: January 1, 1980
Creator: Heusch, B; Beck, C; Coffin, J P; Freeman, R M; Gallmann, A; Haas, F et al.
Partner: UNT Libraries Government Documents Department

A Bremsstrahlung Spectrometer using k-edge and Differential Filters with Image plate dosimeters

Description: A Bremsstrahlung spectrometer using k-edge and differential filtering has been used with Image Plate dosimeters to measure the x-ray fluence from short-pulse laser/target interactions. An electron spectrometer in front of the Bremsstrahlung spectrometer deflects electrons from the x-ray line of sight and simultaneously measures the electron spectrum. The response functions were modeled with the Monte Carlo code Integrated Tiger Series 3.0 and the dosimeters calibrated with radioactive sources. Electron distributions with slope temperatures in the MeV range are inferred from the Bremsstrahlung spectra.
Date: May 2, 2008
Creator: Chen, C; Mackinnon, A; Beg, F; Chen, H; Key, M; King, J A et al.
Partner: UNT Libraries Government Documents Department

Electron-Heated Target Temperature Measurements in Petawatt Laser Experiments Based on Extreme Ultraviolet Imaging and Spectroscopy

Description: Three independent methods (XUV spectroscopy, imaging at 68 eV and 256 eV) have been used to measure planar target rear surface plasma temperature due to heating by hot electrons. The hot electrons are produced by ultra-intense laser plasma interactions using the 150 J, 0.5 ps Titan laser. Soft x-ray spectroscopy in the 50-400 eV region and imaging at the 68 eV and 256 eV photon energies were used to determine the rear surface temperature of planar CD targets. Temperatures were found to be in the 60-150 eV range, with good agreement between the three diagnostics.
Date: May 2, 2008
Creator: Ma, T; Beg, F; Macphee, A; Chung, H; Key, M; Mackinnon, A et al.
Partner: UNT Libraries Government Documents Department

Hot dense matter creation in short-pulse laser interaction with tamped foils

Description: The possibility of producing hot dense matter has important applications for the understanding of transport processes in inertial confinement fusion (ICF) [1] and laboratory astrophysics experiments [2]. While the success of ICF requires the correct solution of a complex interaction between laser coupling, equation-of-state, and particle transport problems, the possibility of experimentally recreating conditions found during the ignition phase in a simplified geometry is extremely appealing. In this paper we will show that hot dense plasma conditions found during ICF ignition experiments can be reproduced by illuminating a tamped foil with a high intensity laser. We will show that temperatures on the order of kiloelectronvolts at solid densities can be achieved under controlled conditions during the experiment. Hydrodynamic tamping by surface coatings allows to reach higher density regimes by enabling the diagnosis of matter that has not yet begun to decompress, thus opening the possibility of directly investigating strongly coupled systems [3]. Our experimental diagnostics is based on K-shell spectroscopy coupled to x-ray imaging techniques. Such techniques have recently become prevalent in the diagnosis of hot dense matter [4]. By looking at the presence, and relative strengths, of lines associated with different ionization states, spectroscopy provides considerable insight into plasma conditions. At the same time, curved crystal imaging techniques allow for the spatial resolution of different regions of the target, both allowing for comparison of heating processes with the results of Particle-In-Cell (PIC) and hybrid simulation codes.
Date: August 15, 2006
Creator: Chen, S; Pasley, J; Beg, F; Gregori, G; Evans, R G; Notley, M et al.
Partner: UNT Libraries Government Documents Department

Fast Ignition relevant study of the flux of high intensity laser generated electrons via a hollow cone into a laser-imploded plasma

Description: An integrated experiment relevant to fast ignition is described. A Cu doped CD spherical shell target is imploded around an inserted hollow Au cone by a six beam 600J, 1ns laser to a peak density of 4gcm{sup -3} and a diameter of 100 {micro}m. A 10 ps, 20TW laser pulse is focused into the cone at the time of peak compression. The flux of high-energy electrons through the imploded material is determined from the yield of Cu K{alpha} fluorescence by comparison with a Monte Carlo model and is estimated to carry 15% of the laser energy. Collisional and Ohmic heating are modeled. An electron spectrometer shows significantly greater reduction of the transmitted electron flux than is due to binary collisions and Ohmic potential. Enhanced scattering by instability-induced magnetic fields is suggested.
Date: October 11, 2005
Creator: Key, M; Adam, J; Akli, K; Borgheshi, M; Chen, M; Evans, R et al.
Partner: UNT Libraries Government Documents Department

Extreme Ultraviolet Imaging of Electron Heated Targets in Petawatt Laser Experiments

Description: The study of the transport of electrons, and the flow of energy into a solid target or dense plasma, is instrumental in the development of fast ignition inertial confinement fusion. An extreme ultraviolet (XUV) imaging diagnostic at 256 eV and 68 eV provides information about heating and energy deposition within petawatt laser-irradiated targets. XUV images of several irradiated solid targets are presented.
Date: November 29, 2007
Creator: Ma, T; MacPhee, A; Key, M; Akli, K; Mackinnon, A; Chen, C et al.
Partner: UNT Libraries Government Documents Department

Fast wave current drive in DIII-D

Description: The non-inductive current drive from fast Alfven waves launched by a directional four-element antenna was measured in the DIII-D tokamak. The fast wave frequency (60 MHz) was eight times the deuterium cyclotron frequency at the plasma center. An array of rf pickup loops at several locations around the torus was used to verify the directivity of the four-element antenna. Complete non-inductive current drive was achieved using a combination of fast wave current drive (FWCD) and electron cyclotron current drive (ECCD) in discharges for which the total plasma current was inductively ramped down from 400 to 170 kA. For discharges with steady plasma current, up to 110 kA of FWCD was inferred from an analysis of the loop voltage, with a maximum non-inductive current (FWCD, ECCD, and bootstrap) of 195 out of 310 kA. The FWCD efficiency increased linearly with central electron temperature. For low current discharges, the FWCD efficiency was degraded due to incomplete fast wave damping. The experimental FWCD was found to agree with predictions from the CURRAY ray-tracing code only when a parasitic loss of 4% per pass was included in the modeling along with multiple pass damping.
Date: February 1, 1995
Creator: Petty, C.C.; Callis, R.W.; Chiu, S.C.; deGrassie, J.S.; Forest, C.B.; Freeman, R.L. et al.
Partner: UNT Libraries Government Documents Department

Plasma heating r and d assessment

Description: The purpose of this report is to compare the heating requirements of INTOR with the present state-of-the-art of tokamak plasma heating technology and demonstrated heating performance, and also with the technology expected by 1983-84 according to development and testing programs in place. This comparison results in a set of recommendations for a heating technology development program for the 1980s.
Date: November 1, 1979
Creator: Jassby, D.L.; Berkner, K.H.; Colestock, P.L.; Freeman, R.L.; Haselton, H.H.; Hosea, J.C. et al.
Partner: UNT Libraries Government Documents Department

Diagnostics for Fast Ignition Science

Description: The concept for Electron Fast Ignition Inertial Confinement Fusion demands sufficient laser energy be transferred from the ignitor pulse to the assembled fuel core via {approx}MeV electrons. We have assembled a suite of diagnostics to characterize such transfer. Recent experiments have simultaneously fielded absolutely calibrated extreme ultraviolet multilayer imagers at 68 and 256eV; spherically bent crystal imagers at 4 and 8keV; multi-keV crystal spectrometers; MeV x-ray bremmstrahlung and electron and proton spectrometers (along the same line of sight); nuclear activation samples and a picosecond optical probe based interferometer. These diagnostics allow careful measurement of energy transport and deposition during and following laser-plasma interactions at extremely high intensities in both planar and conical targets. Augmented with accurate on-shot laser focal spot and pre-pulse characterization, these measurements are yielding new insight into energy coupling and are providing critical data for validating numerical PIC and hybrid PIC simulation codes in an area that is crucial for many applications, particularly fast ignition. Novel aspects of these diagnostics and how they are combined to extract quantitative data on ultra high intensity laser plasma interactions are discussed, together with implications for full-scale fast ignition experiments.
Date: May 6, 2008
Creator: MacPhee, A; Akli, K; Beg, F; Chen, C; Chen, H; Clarke, R et al.
Partner: UNT Libraries Government Documents Department

Fast Electron Generation in Cones with Ultra-Intense Laser Pulses

Description: Experimental results from copper cones irradiated with ultra-intense laser light are presented. Spatial images and total yields of Cu K{sub {alpha}} fluorescence were measured as a function of the laser focusing properties. The fluorescence emission extends into the cone approximately 300 {micro}m from the cone tip and cannot be explained by ray tracing including cone wall absorption. In addition the total fluorescence yield from cones is an order of magnitude higher than for equivalent mass foil targets. Indications are that the physics of the laser cone interaction is dominated by preplasma created from the long duration, low energy pre-pulse from the laser.
Date: December 7, 2007
Creator: Mackinnon, A; VanWoerkom, L; Akli, K; Bartal, T; Beg, F; Chawla, S et al.
Partner: UNT Libraries Government Documents Department