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in creator/contributor: "Turner, W. C."

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Experimental observations and model calculations of impurity radiation in a plasma gun compact torus experiment

Several types of radiation measurements were performed on the Beta II compact forms experiment. Among these are time integrated spectra ranging in wavelength from the vuv to the uv, time resolved bolometer measurements of radiation from the x-ray to the infrared, and time and wavelength resolved measurements of certain spectral lines. It is difficult to relate any one of these measurements to plasma parameters of interest such as temperature, density, or impurity content. In this report we comp… more

Date: August 10, 1982

Creator: Goldenbaum, G. C.; Granneman, E. H. A.; Hartman, C. W.; Prono, D. S.; Taska, J. & Turner, W. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Studies of the Formation of Field Reversed Plasma by a Magnetized Co-Axial Plasma Gun

The gun injects axially into a drift tank followed by a magnetic mirror. For the experiments reported here, only the guide coils outside the vacuum vessel and solenoids on the plasma gun electrodes were used; the mirror coil was not energized. A stainless steel flux conserver is placed in the mirror throat to prevent the plasma from contacting the nonconducting vacuum wall in the region of the mirror. An axis encircling array of magnetic loop probes includes four diamagnetic loops and a loop wh… more

Date: May 28, 1980

Creator: Turner, W. C.; Granneman, E. H. A.; Hartman, C. W.; Prono, D. S.; Taska, J. & Smith, A. C., Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Vacuum measurements on the Tandem Mirror Experiment Upgrade (TMX-U) fusion experiment

The gas inventory of the Tandem Mirror Experiment Upgrade (TMX-U) must be carefully controlled, if it is to successfully create various plasma configurations for thermal-barrier experiments designed to provide an improved performance for tandem-mirror experiments. This paper is a progress report on the calibration methods and pressure measurements of machine conditions deriving from recently improved neutral-beam gas control, and changes to the internal baffling geometry and the gettering syste… more

Date: August 12, 1983

Creator: Calderon, M. O.; Hunt, A. L.; Lang, D. D.; Nexsen, W. E.; Pickles, W. L. & Turner, W. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Control of gas input and background pressure in the end plug regions of the TMX-U thermal barrier experiment

Rate equations for the plasma species in a thermal barrier end plug establish an upper bound on the neutral pressure (P) external to the plasma. For the Tandem Mirror Experiment-Upgrade (TMX-U), this bound is P less than or equal to 0.5 - 1.0 x 10/sup -6/ Torr. Initially TMX-U did not satisfy this criterion, and axial end plugging of plasma losses seemed limited by the excessive pressure. Subsequently, we modified the machine to improve the vacuum conditions, decreasing P to the desired range. … more

Date: October 26, 1983

Creator: Turner, W. C.; Nexsen, W. E.; Allen, S. L.; Hooper, E. B.; Hunt, A. L.; Lang, D. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Tandem mirror experiment-upgrade vacuum system: a new configuration and operating parameters

The Tandem Mirror Experiment-Upgrade (TMX-U) vacuum system has been installed and operating since December 1981. In 1982 and early 1983 the performance of the internal, dynamic pumping system was evaluated during physics experiments. The plasma region gas loads caused the pressure to exceed that allowable for achieving thermal barrier plasmas. The unified, multiple-beamline concept used on TMX-U to pump the neutral-beam injector gas was modified. The modifications to the system were designed to… more

Date: December 2, 1983

Creator: Lang, D. D.; Calderon, M. O.; Hunt, A.; Nexsen, W. E.; Pickles, W. L. & Turner, W. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Multi-channel neutral analyzer-system

Design and calibration of a 15 channel multi-channel analyzer for analysis of energetic neutral particles escaping a hot plasma are discussed. Features of the analyzer include a frequency response from DC to 50 kHz, spatial resolution, mass resolution, and data acquisition and processing for 15 points on the energy distribution that are simultaneously recorded. Another feature of the system is the ability to radially scan the plasma. An rf ion source is used to provide ions and neutrals used fo… more

Date: September 14, 1977

Creator: Nexsen, Jr., W. E.; Turner, W. C. & Cummins, W. F.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Field reversal produced by a plasma gun

Experimental results are presented of the production of Field-Reversed Plasma with a high energy coaxial plasma gun. The gun is magnetized with solenoids inside the center electrode and outside the outer electrode so that plasma emerging from the gun entrains the radial fringer field at the muzzle. The plasma flow extends field lines propagating a high electrical conductivity, the flux inside the center electrode should be preserved. However, for low flux, the trapped flux exceeds by 2 or more … more

Date: April 2, 1980

Creator: Hartman, C. W.; Condit, W.; Granneman, E. H. A.; Prono, D.; Smith, A. C., Jr.; Taska, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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300-kJ, 200-kA Marx module for Antares

Antares is a 100-kJ CO/sub 2/ laser driver for inertial confinement fusion experiments. The power amplification stage is pumped by an electron-beam-controlled gas discharge. There are 24 annular discharge regions, each requiring energy input of 250 kJ at 550 kV, in a 2-used pulse. The energy storage module chosen for this system is a single-mesh pulse-forming network. To provide sufficient energy margin each module stores 300 kJ. A prototype 300-kJ Marx has been built and tested at the Los Alam… more

Date: January 1, 1979

Creator: Riepe, K. B.; Bickford, K. J.; Jansen, J. & Turner, W. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Reduction of energy sweep of the ETA-II beam

The ETA-2 electron beam will be used to drive a high power microwave frequency FEL for plasma heating experiments. For maximum FEL output power the beam energy at the entrance to the wiggler should be within {plus minus}1% of the wiggler resonance value. In initial operations the ETA-2 beam energy stayed within this range for a maximum time of less than 13 ns, Much of the energy variation was due to the design of the pulsed power feeds to the of the pulsed power feeds to the accelerator inducti… more

Date: May 1, 1991

Creator: Nexsen, W. E.; Allen, S. L.; Chambers, F. W.; Jong, R. A.; Paul, A. C.; Sampayan, S. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Plasma-Parameter Measurements Using Neutral-Particle-Beam Attenuation

Intense and energetic neutral-particle-beam injection used for fueling or heating magnetically confined, controlled-fusion experimental plasmas can also provide diagnostic measurements of the plasmas. The attenuation of an atomic beam (mainly from charge-exchange and ionization interactions) when passing through a plasma gives the plasma line density. Orthogonal arrays of highly collimated detectors of the secondary-electron-emission type have been used in magnetic-mirror experiments to measure… more

Date: July 7, 1982

Creator: Foote, J. H.; Molvik, A. W. & Turner, W. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Improvement of tubulars used for fracturing in hot dry rock wells

Completion of hot dry rock wells as it is currently envisioned, requires that hydraulic fracturing be used to develop a heat extraction reservoir and to provide low impedance flow paths between the designated water injection and production wells. Recent fracturing operations at measured depths from 11,400 ft to 15,300 ft at the Fenton Hill Hot Dry Rock Geothermal Test Site have resulted in numerous failures of tubulars caused by the high fracturing pressures, corrosive environment and large tre… more

Date: April 1, 1984

Creator: Nicholson, R. W.; Dreesen, D. S. & Turner, W. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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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 o… more

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Free-electron laser experiments in the microwave tokamak experiment

Microwave pulses have been injected from a free electron-laser (FEL) into the Microwave Tokamak Experiment (MTX) at up to 0.2 GW at 140 GHz in short pulses (10-ns duration) with O-mode polarization. The power transmitted through the plasma was measured in a first experimental study of high power pulse propagation in the plasma; no nonlinear effects were found at this power level. Calculations indicate that nonlinear effects may be found at the higher power densities expected in future experimen… more

Date: August 1, 1990

Creator: Allen, S. L.; Brown, M. D.; Byers, J. A.; Casper, T. A.; Cohen, B. I.; Cohen, R. H. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Energy sweep compensation of induction accelerators

The ETA-II linear induction accelerator (LIA) is designed to drive a microwave free electron laser (FEL). Beam energy sweep must be limited to {plus minus}1% for 50 ns to limit beam corkscrew motion and ensure high power FEL output over the full duration of the beam flattop. To achieve this energy sweep requirement, we have implemented a pulse distribution system and are planning implementation of a tapered pulse forming line (PFL) in the pulse generators driving acceleration gaps. The pulse di… more

Date: September 12, 1990

Creator: Sampayan, S. E.; Caporaso, G. J.; Chen, Y. J.; Decker, T. A. & Turner, W. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Development of coring, consolidating, subterrene penetrators

Coring penetrators offer two advantages over full face-melting penetrators, i.e., formation of larger boreholes with no increase in power and the production of glass-lined, structurally undisturbed cores which can be recovered with conventional core-retrieval systems. These cores are of significant value in geological exploratory drilling programs. The initial design details and fabrication features of a 114-mm-diam coring penetrator are discussed; significant factors for design optimization ar… more

Date: February 1, 1976

Creator: Murphy, H. D.; Neudecker, J. W.; Cort, G. E.; Turner, W. C.; McFarland, R. D. & Griggs, J. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Electrostatic ion cyclotron waves and ion energy diffusion in a mirror machine. [2XIIb machine]

Measurements of ion cyclotron fluctuations and ion energy diffusion in the neutral beam injected 2XIIB mirror machine are presented. A narrow band single mode spectrum is always observed. When the plasma is de-stabilized by turning off axially injected streaming plasma, the wave amplitude increases and a simultaneous increase in ion-energy diffusion is observed. The spectral properties of the wave do not change. The data are in accord with a wave particle saturation of the drift cyclotron loss … more

Date: August 1, 1977

Creator: Turner, W. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Plasma wall charge-exchange interactions in the 2XIIB magnetic mirror experiment

Plasma-wall interactions by charge-exchange wall bombardment in the 2XIIB magnetic mirror experiment are discussed. Experimental measurements are modeled with a time-dependent, radial density buildup calculation. A low-density plasma sufficient to help shield the hot interior plasma from cold-gas erosion, as required by the model, is measured.

Date: January 1, 1976

Creator: Stallard, B. W.; Coensgen, F. H.; Cummins, W. F.; Gormezano, C.; Logan, B. G.; Molvik, A. W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Fabrication of superconductors. [NbTi in Cu, CuNi matrix]

The paper discusses the development of a process for making high performance, fine-filament superconducting wires, utilizing dual matrix stabilization and Nb/sub 46/Ti superconducting filaments. Minimum filament size-achieved was 8 ..mu..m using OFHC copper and Cu/sub 30/Ni matrix materials. Ductility of the NbTi starting material was found to exert a major influence on the properties of the finished wire, and specifications for acceptable NbTi were developed. When specific impurity levels are … more

Date: January 1, 1976

Creator: Turner, W. C.; Lundberg, L. B.; Zeitlin, B.; deWinter, T. A. & McDonald, W. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Investigation of synchrotron radiation-induced photodesorption in cryosorbing quasi-cooled geometry. Revision 2

We report 4.2-K photodesorption experiments in two quasi -- closed geometries-a simple tube and a tube with a coaxial perforated liner -- designed to manure separately the desorption coefficients of tightly bound and physisorbed molecules. The results are important for the beam tube vacuum of the next generation of superconducting proton colliders that have been contemplated-the 20-TeV Superconducting Super Collider (SSC) in the United States and the 7.3-TeV Large Hadron Collider (LHC) at CERN.

Date: April 1, 1994

Creator: Anashin, V. V.; Malyshev, O. B.; Osipov, V. N.; Maslennikov, I. L. & Turner, W. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Recent experimental progress in the TMX-U thermal barrier tandem mirror experiment

Recent experiments on the TMX-U thermal barrier device at LLNL have achieved the end plugging of axial ion losses up to a central cell density of n/sub c/ = 2 x 10/sup 12/ cm. During these tests, the axial potential profile characteristic of a thermal barrier has been measured experimentally, indicating an ion-confining potential greater than 1.5 kV and a potential depression of 0.45 kV in the barrier region. The average beta of hot electrons in the thermal barrier has been increased to 15% and… more

Date: June 22, 1984

Creator: Turner, W. C.; Allen, S. L.; Casper, T. A.; Clauser, J. F.; Coensgen, F. H.; Correll, D. L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Formation of Compact Toroidal Plasmas by Magnetized Coaxial Plasma Gun Injection Into an Oblate Flux Conserver

Initial results are reported on the formation of compact toroidal plasmas in an oblate shaped metallic flux conserver. A schematic of the experimental apparatus is shown. The plasma injector is a coaxial plasma gun with solenoid coils wound on the inner and outer electrodes. The electrode length is 100 cm, the diameter of the inner (outer) electrode is 19.3 cm (32.4 cm). Deuterium gas is puffed into the region between electrodes by eight pulsed valves located on the outer electrode 50 cm from t… more

Date: November 4, 1980

Creator: Turner, W. C.; Goldenbaum, G. C.; Granneman, E. H. A.; Hartman, C. W.; Prono, D. S.; Taska, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Measurement and Simulation of Whole Beam Brightness on the ETA-II (Experimental Test Accelerator-II) Linear Induction Accelerator

Measurement of beam radius as a function of focusing strength of an upstream solenoidal field allows simultaneous determination of the beam energy, brightness and tilt of the phase space ellipse. On ETA-II beam radius has been measured by analyzing foil emitted Cherenkov light with a gated (5 ns) image intensified CCD camera. The beam energy measurement is corroborated with a spectrometer magnet and core brightness with a two hole emittance diagnostic. For a 6 MeV, 1.6 kA beam, the whole beam b… more

Date: August 7, 1990

Creator: Chen, Y. J.; CLark, J. C.; Paul, A. C.; Nexsen, W. E. & Turner, W. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The development of a positron ionization gauge

The authors present a method by which gas pressure (density) can be measured by positrons. The process to monitor is the formation of positronium, Ps, via electron capture by the e{sup +} from the rest gas molecules. The Ps signal which is proportional to the gas density is obtained from the annihilation photons which are emitted when the Ps atom decays. By this method it is not necessary to have access to the vacuum system in question other than having the possibility of passing a positron bea… more

Date: January 1, 1994

Creator: Jacobsen, F.; Strongin, M.; Ruckman, M.; Wiess, A. & Turner, W. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Using the BRAN Luminosity Detectors for Beam Emittance Monitoring During LHC Physics Runs

No Description Available.

Date: October 16, 2013

Creator: White, S. M.; Bravin, E.; Miyamoto, R.; McCrory, E. S. M.; Matis, H. S.; Placidi, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department