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  • 1
    Electronic Resource
    Electronic Resource
    Performance evaluation of the TFTR gyrotron CTS diagnostic for alpha particles : Proceedings of the 9th topical conference on high temperature plasma diagnostics (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 4644-4646 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A large-angle, 60-GHz collective Thomson scattering (CTS) diagnostic system for localized measurements of DT alpha-particle velocity distribution and fraction is being implemented on TFTR. Calculations of expected CTS spectra, signal-to-noise ratio per receiver channel, and estimated error in determining the temperature and fraction of alpha particles are being carried out. The experimental spectra are simulated by adding noise to the theoretical calculation by a Monte Carlo technique. Error analysis is then performed by using a relative intensity calibrated nonlinear curve fitting code to calculate the desired plasma parameters (Ti, Tα, nα/ni). Simulation results indicate that expected background emission of 20 eV during Supershot in TFTR poses no problem to the experiment. Also short integration times (〈10 ms) can be used to resolve the energetic ion features, thus offering a possibility for the study of temporal evolution of energetic ion velocity distribution during a single plasma shot.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143646
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  • 2
    Electronic Resource
    Electronic Resource
    Characteristics of gyrotron scattering system for α particle diagnostics in TFTR (abstract) : Proceedings of the 9th topical conference on high temperature plasma diagnostics (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 4647-4647 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In D-T plasmas, the understanding of the physics of confined α particles is extremely valuable for the future fusion plasma device. Among the various proposed α diagnostics, an X-mode collective Thomson scattering system employing a high-power gyrotron source (P(approximately-equal-to)200 kW, f=60 GHz, pulse length (approximately-equal-to)0.5 s, and modulation frequency=10–25 kHz) is being designed for TFTR. The detailed description of the gyrotron source, transmission lines, optical designs, beam and viewing dump design, and receiver system will be presented in this paper. In particular, the test results of the beam and viewing dump indicate that the stray light can be reduced by 60 dB. The background emission level (∼20 eV) near 60-GHz range during high Q discharge may also be reduced with beam and viewing dump further. The optical system is designed to measure the radial profile of α particles and to orient the incident wavevector (k0) to test the electromagnetic effects of the scattered spectrum. Prior to the study of α physics in D-T plasmas, this scattering system will be used to measure not only a bulk ion temperature but also the scattered spectrum due to fast ions produced by NB and ICRF heating in TFTR. This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76-CHO-3073.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143647
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Development of high-power millimeter and submillimeter wavelength collective Thomson scattering diagnostics for energetic ion measurements in tokamaks : EIGHT TOPICAL CONFERENCE ON HIGH−TEMPERATURE PLASMA DIAGNOSTICS (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 3544-3547 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: High-power, large-angle ((approximately-greater-than)10°), collective Thomson scattering diagnostics can provide localized density and velocity distribution data of confined alpha particles, ICRH simulated alpha particles, and ions related to ICRH and neutral beam energy deposition. Millimeter-wave gyrotron systems are under development for TFTR and JET. Scattering with a submillimeter gyrotron is being investigated for Alcator C-Mod. Major design issues include plasma accessibility, scattering angle, orientation to magnetic field, spectra of non-Maxwellian velocity distributions, signal-to-noise ratio, refraction, electron cyclotron emission, and beam and viewing dumps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141567
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  • 4
    Electronic Resource
    Electronic Resource
    Design of a third-harmonic electron cyclotron emission diagnostic for ballooning mode fluctuations in PBX-M : Eight topical conference on high-temperature plasma diagnostics (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 2995-2997 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A third-harmonic electron cyclotron emission diagnostic using ultrawide bandwidth (≈40 GHz) heterodyne receivers centered on 120 GHz with 14 channels per radial view is described for localized, long wavelength (5(approximately-less-than)λ(approximately-less-than)50 cm), fast time response (≈1 μs) fluctuation studies in the PBX-M tokamak. The optically gray emission signal will have a γñe/ne+(3/β)T˜e/Te dependence on temperature and density fluctuations where γ≤1 and 1≤β≤3 depending on local optical depth. Electron temperature fluctuation sensitivity is estimated to be 0.2%≤T˜e/Te ≤2.9% depending on local optical depth and fluctuation frequency in the 0.1–1 MHz range. Spatial resolution of approximately 3 cm radially and 5 cm vertically are estimated for 2 keV plasmas with low suprathermal electron emission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141758
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  • 5
    Electronic Resource
    Electronic Resource
    Active millimeter-wave pyrometer (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 4241-4248 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A 135 GHz heterodyne receiver with a rotatable graphite waveguide/mirror system has been implemented on a waste remediation direct-current arc furnace for internal surface temperature measurements. The linear temperature measurement range extends from 〈1° to approximately 15,000 °C relative to ambient with a simultaneous capability to monitor surface reflectivity with the local oscillator leakage. Reliable and robust operation on a continuous 24 h basis in a smoky, dirty furnace environment is demonstrated for a total of five furnace runs reaching a maximum temperature of 2200 °C. Complete temperature profile measurements with approximately 5 cm spatial resolution clearly documented thermal gradients on the slag melt surface and refractory walls and ceiling for all operating regimes of the furnace. The unique active probing capability of this instrument provided additional real-time information on melt surface turbulence, changing furnace wall emissivity, and millimeter-wave optic losses inside the furnace. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145376
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  • 6
    Electronic Resource
    Electronic Resource
    Precision terahertz relative reflectometry using a blackbody source and heterodyne receiver (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 438-444 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Instrumentation for making localized, precise relative reflection measurements of metals and superconductors in the terahertz frequency range is demonstrated. The results can be used to determine the surface resistivity of these materials which is of particular importance to development of high-temperature superconductors. Emission from a commerically available 1000 °C blackbody source was reflected from the materials under test and a reference reflector. The reflected signals were detected by a Schottky diode heterodyne receiver using a CO2-laser-pumped 214.5 μm CH2F2 laser as the local oscillator. Double-sideband bandwidth and receiver noise temperature were 2 GHz and 30 000 K, respectively. The use of a broadband incoherent diagnostic source minimizes instrumentation sensitivity to coherent interference effects. The heterodyne receiver provides for sensitive detection with good spatial and frequency resolution. Unoptimized spatial resolution of four times the diffraction limit was achieved. The potential for relative reflectivity measurement accuracy of better than 0.1% was demonstrated with 30 min measurement times though systematic errors limited actual measurement accuracy to about 0.3%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145153
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  • 7
    Electronic Resource
    Electronic Resource
    Microwave plasma continuous emissions monitor for trace-metals in furnace exhaust (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 3700-3707 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A microwave plasma continuous emissions monitor has been successfully demonstrated for sensitive (〈1 ppb), real time measurements of trace metals in furnace exhaust. The instrument uses a robust, up to 1.5 kW, 2.45 GHz microwave plasma sustained in a portion of the undiluted furnace exhaust flow for atomic emission spectroscopy. The waveguide device is constructed of refractory materials compatible with high-temperature environments ((approximately-greater-than)500 °C) and is flange mountable into the inside of the furnace exhaust duct. Fused quartz fiber optics in close proximity to the plasma flame transmit the UV through visible emission (190–690 nm) to three spectrometers for simultaneous monitoring of several metals. This instrument has been used for continuous monitoring for a 49 h period with 0.5 s time resolution on a dc graphite electrode arc furnace during a soil vitrification test. Results are presented for chromium, manganese, and iron emissions during soil loading operations. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147058
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  • 8
    Electronic Resource
    Electronic Resource
    Decomposition of 1,1-Dichloroethane and 1,1-Dichloroethene in an electron beam generated plasma reactor (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 2863-2868 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An electron beam generated plasma reactor is used to decompose low concentrations (100–3000 ppm) of 1,1-dichloroethane and 1,1-dichloroethene in atmospheric pressure air streams. The energy requirements for 90% and 99% decomposition of each compound are reported as a function of inlet concentration. Dichloroethene decomposition is enhanced by a chlorine radical propagated chain reaction. The chain length of the dichloroethene reaction is estimated to increase with dichloroethene concentration from 10 at 100 ppm initial dichloroethene concentration to 30 at 3000 ppm. Both the dichloroethane and dichloroethene reactions seem to be inhibited by electron scavenging decomposition products. A simple analytic expression is proposed for fitting decomposition data where inhibition effects are important and simple first order kinetics are not observed. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363945
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  • 9
    Electronic Resource
    Electronic Resource
    Calculated collective Thomson scattered spectra from tokamak plasma with non-Maxwellian ions : Eight topical conference on high-temperature plasma diagnostics (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 3217-3219 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Theoretical scattered spectra from energetic ions in tokamak plasmas (TFTR and Alcator C-Mod) are calculated. A new numerical code that calculates the collective Thomson scattered spectrum with a completely arbitrary distribution function was developed to model scattered spectra in ICRF heated and DT burning plasmas. Calculated spectra for nonthermal minority He3 ions in ICRF heated plasmas along with results from Maxwellian distributions are shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141638
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  • 10
    Electronic Resource
    Electronic Resource
    Development of high-power millimeter and submillimeter wavelength collective Thomson scattering diagnostics for energetic ion measurements in tokamaks (abstract) : Eight topical conference on high-temperature plasma diagnostics (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 3232-3232 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: High-power, large-angle ((approximately-greater-than)10°), collective Thomson scattering diagnostics can provide localized density and velocity distribution data of confined alpha particles, ICRH simulated alpha particles, and ions related to ICRH and neutral beam energy deposition. Millimeter-wave gyrotron systems are under development for TFTR and JET. Scattering with a submillimeter gyrotron is being investigated for Alcator C-Mod. Major design issues include plasma accessibility, scattering angle, orientation to magnetic field, spectra of non-Maxwellian velocity distributions, signal-to-noise ratio, refraction, electron cyclotron emission, and beam and viewing dumps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141649
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    Paper (German National Licenses)
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