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Reconstruction of plasma radiation features from projections measured with two bolometer arrays

Description: A specialized method has been developed to maximize the two-dimensional detail obtained from two perpendicular bolometer arrays. The technique relies on the assumption that poloidal variations exists only near the plasma surface. The cross section is divided into appropriate zones, and the emittance is reconstructed by a numerical method. The position, intensity, and width of large features are clearly displayed. A marfe is tracked as it drifts around the plasma and evolves into a radiating shell detached from the limiter. A central peak, plus inner-wall radiating layer, plus a marfe appear in a high-density case reached by pellet injection.
Date: September 1, 1986
Creator: Schivell, J.
Partner: UNT Libraries Government Documents Department

Periscope-camera system for visible and infrared imaging diagnostics on TFTR

Description: An optical diagnostic consisting of a periscope which relays images of the torus interior to an array of cameras is used on the Tokamak Fusion Test Reactor (TFTR) to view plasma discharge phenomena and inspect vacuum vessel internal structures in both visible and near-infrared wavelength regions. Three periscopes view through 20-cm-diameter fused-silica windows which are spaced around the torus midplane to provide a viewing coverage of approximately 75% of the vacuum vessel internal surface area. The periscopes have f/8 optics and motor-driven controls for focusing, magnification selection (5/sup 0/, 20/sup 0/, and 60/sup 0/ field of view), elevation and azimuth setting, mast rotation, filter selection, iris aperture, and viewing port selection. The four viewing ports on each periscope are equipped with multiple imaging devices which include: (1) an inspection eyepiece, (2) standard (RCA TC2900) and fast (RETICON) framing rate television cameras, (3) a PtSi CCD infrared imaging camera, (4) a 35 mm Nikon F3 still camera, or (5) a 16 mm Locam II movie camera with variable framing up to 500 fps. Operation of the periscope-camera system is controlled either locally or remotely through a computer-CAMAC interface. A description of the equipment and examples of its application are presented.
Date: May 1, 1985
Creator: Medley, S.S.; Dimock, D.L.; Hayes, S.; Long, D.; Lowrence, J.L.; Mastrocola, V. et al.
Partner: UNT Libraries Government Documents Department

Long-term changes in the sensitivity of quadrupole mass spectrometers

Description: We routinely use quadrupole mass spectrometers (QMS) to monitor vacuum conditions, gas purity, and plasma-wall interactions in the Tokamak Fusion Test Reactor (TFTR) at Princeton. Two QMS systems have been operating on TFTR continuously for a two-year period. Both QMS systems are absolutely calibrated at weekly intervals using a six-part standard gas mixture. The calibration procedure is based on the use of transfer standards (ion gauge and capacitance manometer) that are calibrated against a primary standard (spinning rotor gauge) on an external vacuum system. We have identified variations in the efficiency of the QMS ionizer and drifts in the sensitivity of the electron multiplier ion detector to be the major reasons for the observed changes in overall OMS sensitivity. Weekly variations in sensitivity greater than 100% have been observed following system bakeout at 150/sup 0/C and with the use of rhenium filaments which were initially in the QMS ionizer. Operation of the QMS systems with tungsten filaments and at constant temperature has yielded more stable operation with weekly sensitivity changes generally being less than 10%. 7 refs., 7 figs.
Date: February 1, 1986
Creator: Blanchard, W.R.; McCarthy, P.J.; Dylla, H.F.; LaMarche, P.H. & Simpkins, J.E.
Partner: UNT Libraries Government Documents Department

Overview of the first workshop on alpha particle physics in TFTR

Description: The First Workshop on Alpha Physics in TFTR'' was held at the Princeton Plasma Physics Lab March 28--29, 1991. The motivation for this meeting was to clarify and strengthen the TFTR alpha physics program, and to increase the involvement of the fusion community outside PPPL in the TFTR D-T experiments. Therefore the meeting was sharply focused on alpha physics relevant to the upcoming TFTR D-T simulation, and was asked to devote half of his talk to specific TFTR issues. The Workshop consisted of 27 talks on: (1) experimental possibilities; (2) theoretical possibilities; (3) diagnostic possibilities; (4) relevance for future machines; and (5) discussion/summary session. This summary contains a brief sampling of the new results and ideas brought out by these talks, followed by two more general overviews of the status of experiment and theory.
Date: July 1, 1991
Creator: Zweben, S.J. & Biglari, H.
Partner: UNT Libraries Government Documents Department

Calibration of the FIR polarimeter on TFTR tokamak

Description: The results of the first Faraday rotation measurement on the TFTR tokamak are presented. Data are reported on ohmic- as well as neutral-beam-heated plasmas including solid pellet injections. The procedure and the results of the calibration are described. The effects of various errors in the measurements as well as the problem of cross coupling laser beams are studied.
Date: January 1, 1985
Creator: Ma, C.H.; Hutchinson, D.P.; Vander Sluis, K.L.; Mansfield, D.K.; Park, H. & Johnson, L.C.
Partner: UNT Libraries Government Documents Department

Lower limits for parallel impurity fluxes in the PLT edge plasma

Description: Lower limits for time-resolved anti B-parallel impurity fluxes to solid collectors immersed in the PLT edge plasma have been determined as a function of minor radius. Using geometric shadowing of the probe surface, features attributed to finite ion gyroradii have been observed. Also, for r less than 48 cm, heat pulses of less than 2 ms duration and greater than 2.5 x 10/sup 3/ W/cm/sup 2/ intensity were found to occur at the termination of many discharges.
Date: May 1, 1978
Creator: Cohen, S.A. & Dylla, H.F.
Partner: UNT Libraries Government Documents Department

Real time acquisition, processing, and archiving of Doublet III diagram data employing table driven software

Description: This paper describes the diagnostic data acquisition, processing and archiving computer system for the Doublet III fusion research device. This paper's emphasis is mainly on the software, but provides a description of the hardware configuration. (MOW)
Date: November 1, 1979
Creator: Glad, A.; Henline, P.; Gross, L. & McHarg, B.
Partner: UNT Libraries Government Documents Department

Spectra of germanium and selenium in the 50-350 A region from the PLT tokamak plasma

Description: Spectra of germanium and selenium injected into the PLT tokamak plasma were observed in the 50 to 350 A region for GeXIV-XXV (KI to OI-like) and SeXVI-XXIV (KI to NaI-like). A number of 3p/sup k/-3p/sup k-1/3d transitions predicted by isoelectronic sequence extrapolation have been identified. Also, previously identified lines from ions in the AlI to OI-like and KI-like isoelectronic sequences have been observed in the tokamak plasma.
Date: March 1, 1983
Creator: Stratton, B.C.; Hodge, W.L.; Moos, H.W.; Schwob, J.L.; Suckewer, S.; Finkenthal, M. et al.
Partner: UNT Libraries Government Documents Department

Impurity studies in fusion devices using laser-fluorescence-spectroscopy

Description: Resonance fluorescence excitation of neutral atoms using tunable radiation from dye lasers offers a number of unique advantages for impurity studies in fusion devices. Using this technique, it is possible to perform local, time-resolved measurements of the densities and velocity distributions of metallic impurities in fusion devices without disturbing the plasma. Velocities are measured by monitoring the fluorescence intensity while tuning narrow bandwidth laser radiation through the Doppler - broadened absorbtion spectrum of the transition. The knowledge of the velocity distribution of neutral impurities is particularly useful for the determination of impurity introduction mechanisms. The laser fluorescence technique will be described in terms of its application to metallic impurities in fusion devices and related laboratory experiments. Particular attention will be given to recent results from the ISX-B tokamak using pulsed dye lasers where detection sensitivities for neutral Fe of 10/sup 6/ atoms/cm/sup 3/ with a velocity resolution of 600 m/sec (0.1 eV) have been achieved. Techniques for exciting plasma particles (H,D) will also be discussed.
Date: August 1, 1980
Creator: Husinsky, W.R.
Partner: UNT Libraries Government Documents Department

Design calculations for a neutron collimator for the TFTR

Description: Some of the design calculations for a collimator for TFTR application are presented and discussed. Discrete ordinates transport calculations have been completed for several right circular cylindrical stainless steel collimators using a 14-MeV neutron, isotropic, 30-cm radius disc source to approximate a plasma volume source. The collimators considered in these survey calculations consisted of 3-cm diameter columns centrally located in 60-cm diameter stainless steel cylinders that varied in length from 30 to 180 cm. The source-collimator-detector configurations consisted of the uniform disc source located 60 cm from the entrance of each collimator and a 6-cm diameter 6-cm long right circular cylinder detector located at various distances from the exit of each collimator. The configurations were analyzed with the first collision source code GRTUNCL and the two-dimensional discrete ordinates code DOT III using an S/sub 4/ angular quadrature. (MHR)
Date: January 1, 1977
Creator: Lillie, R.A.; Alsmiller, R.G. Jr. & Mihalczo, J.T.
Partner: UNT Libraries Government Documents Department

Performance study of the TFTR diagnostic neutral beam for active charge exchange measurements

Description: A neutral beam source will be incorporated in the Tokamak Fusion Test Reactor (TFTR) charge exchange diagnostic to provide a time modulated, spatially localized enhancement of the charge exchange efflux. Two autonomous Charge Exchange Neutral Analyzer (CENA) systems are being designed for the TFTR. One system measures the plasma ion temperature along twelve vertical line-of-sight chords spaced approximately equidistantly across the torus minor diameter. The other system is dedicated primarily to measurement of ion phenomena associated with neutral beam injection heating and has a fan-like field of view along eight sight-lines in the equitorial plane. The neutral beam is steerable in order to access the viewing field of both CENA systems, though in general not simultaneously. The performance of the diagnostic neutral beam is evaluated to determine the optimal beam specifications for active charge exchange measurements. Using the optimal beam design parameters, the efficacy of the neutral doping is examined for both CENA systems over the envisioned range of the TFTR plasma density and temperature.
Date: June 1, 1980
Creator: Medley, S.S.; Goldston, R.J. & Towner, H.H.
Partner: UNT Libraries Government Documents Department

Plasma density measurements using FM-CW millimeter wave radar techniques

Description: Modified FM-CW radar techniques using swept millimeter-wave oscillators are useful for determining when a particular density has been reached in a plasma. Narrowband measurements on the Princeton Large Torus (PLT) demonstrate the suitability of these techniques for controlling high-power auxiliary plasma heating systems. Broadband measurements using these same techniques are proposed, by which the density profile could be determined.
Date: September 1, 1980
Creator: Doane, J.L.; Mazzucato, E. & Schmidt, G.L.
Partner: UNT Libraries Government Documents Department

Identification of magnetic dipole lines above 2000 A in several Mo and Zr ions on the PLT tokamak

Description: A number of spectrum lines arising from magnetic dipole transitions in the n = 3 shell ground configurations of molybdenum and zirconium ions have been identified. These lines are particularly suitable for spectroscopic diagnostics in tokamak-type plasmas in the 500 to 1500 eV temperature range.
Date: May 1, 1982
Creator: Suckewer, S.; Hinnov, E.; Cohen, S.; Finkenthal, M. & Sato, K.
Partner: UNT Libraries Government Documents Department

Introduction to magnetic confinement fusion diagnostics

Description: These notes present a brief survey of some of the current diagnostic techniques used in magnetic fusion plasma devices. To give an idea of the range of parameters and geometries encountered the parameters of four representative experiments - PLT, TMX, ZT-40 and EBT-I(S) - are given. The central issue of all experiments is to understand the flow of power which can be summarized by two volume integrated equations for the ions and electrons.
Date: June 6, 1980
Creator: Turner, W.C.
Partner: UNT Libraries Government Documents Department

Fusion gamma diagnostics

Description: Nuclear reactions of interest in fusion research often possess a branch that yields prompt emission of gamma radiation in excess of 15 MeV. This branch can be exploited to provide a new fusion reaction diagnostic having applications similar to conventional neutron emission measurements. Conceptual aspects of fusion gamma diagnostics are discussed with emphasis on application to TFTR during deuterium neutral beam heating of D-T and D-/sup 3/He plasmas. Recent measurements of the D(T, ..gamma..)/sup 5/He, D(/sup 3/He, ..gamma..)/sup 5/Li, and D(D, ..gamma..)/sup 4/He branching ratios at low center-of-mass energy (30 to 100 keV) and of the response of a large volume Ne226 detector for gamma detection in high neutron backgrounds are presented. For a well-shielded Ne226 detector, the D(T, ..gamma..)/sup 5/ He gamma signal level during 20 MW to 120 keV deuterium neutral beam heating of a TFTR tritium plasma was estimated to be 3.5 x 10/sup 5/ CPS.
Date: December 1, 1984
Creator: Medley, S.S.; Cecil, F.E.; Cole, D.; Conway, M.A. & Wilkinson, F.J. III
Partner: UNT Libraries Government Documents Department

Performance of the TFTR bolometers

Description: For the past year we have been making use of a horizontally viewing 19-channel array and a bolometer which views a narrow cross-sectional slice of the plasma. More recently, we have also obtained results from a second, vertically viewing array. Software has been developed to translate the data from general plasma and array locations to plasma minor radius and to do the Abel inversion with an antisymmetrical term included. Experience has been obtained on the noise and response-time characteristics, as well as the accuracy of total radiated power and radial profiles. Representative cases of radiated power profiles and local power balance are presented, as well as comparisons with other measurements of impurity concentration and trends with electron density and limiter coating. Although most of the ohmic-heating input power leaves by radiation, most of this loss occurs near the outer part of the plasma. Also, the behavior of power profiles during neutral beam injection and disruptions is discussed briefly.
Date: January 1, 1985
Creator: Schivell, J.
Partner: UNT Libraries Government Documents Department

MIRI: A multichannel far-infrared laser interferometer for electron density measurements on TFTR (Tokamak Fusion Test Reactor)

Description: A ten-channel far-infrared laser interferometer which is routinely used to measure the spatial and temporal behavior of the electron density profile on the TFTR tokamak is described and representative results are presented. This system has been designed for remote operation in the very hostile environment of a fusion reactor. The possible expansion of the system to include polarimetric measurements is briefly outlined. 13 refs., 8 figs.
Date: July 1, 1987
Creator: Mansfield, D.K.; Park, H.K.; Johnson, L.C.; Anderson, H.M.; Chouinard, R.; Foote, V.S. et al.
Partner: UNT Libraries Government Documents Department

Millimeter radiometer techniques for plasma temperature diagnostics

Description: Radiometers have been employed in radio telescopes to measure stellar plasma temperatures. However, when electron temperature measurements are made on hot dense plasmas in thermonuclear fusion research, radiometry techniques are modified. This report discusses these modifications as they are incorporated in radiometers on the PLT device. Included is a list of proposed radiometer developments and techniques for the PLT, PDX, and TFTR devices.
Date: November 1, 1979
Creator: Bitzer, R.A.
Partner: UNT Libraries Government Documents Department

Multichord time-resolved electron temperature measurements by the x-ray absorber-foil method on TFTR

Description: Absorber foils have been installed in the TFTR X-Ray Imaging System to permit measurement of the electron temperature along 10 to 30 chords spaced at 5-12.5 cm with a time resolution of less than 100 ..mu..s. The technique uses the ratio of x-ray fluxes transmitted through two different foils. The ratio depends mainly on electron temperature. Simulations show that strong impurity line radiation can distort this ratio. To correct for these effects, special beryllium-scandium filters are employed to select the line-free region between 2 and 4.5 keV. Other filter pairs allow corrections for Fe L and Ni L line radiation as well as Ti K and Ni K emission. Good accuracy is also obtained with simple beryllium filters, provided that impurity corrections are incorporated in the analysis, taking line intensities from the x-ray pulse-height analysis diagnostic. A description of modeling calculations and a comparison of temperature values from this diagnostic with data from the x-ray pulse height analysis, the electron cyclotron emission, and the Thomson scattering diagnostics are presented. Several applications of the absorber foil electron temperature diagnostic on TFTR are discussed.
Date: September 1, 1985
Creator: Kiraly, J.; Bitter, M.; Efthimion, P.; von Goeler, S.; Grek, B.; Hill, K.W. et al.
Partner: UNT Libraries Government Documents Department

One millimeter wave interferometer for the measurement of line integral electron density on TFTR

Description: A two-pass interferometer at 285 GHz has been developed to measure the line-integrated electron density on the horizontal midplane of the Toroidal Fusion Test Reactor (TFTR). Presently, the interferometer employs a 2 MW solid state source to supply the launch wave, a 2 mm klystron oscillator, and a harmonic mixer to provide a superheterodyne front end. The transmission system consists of 25 meters of C-band rectangular waveguide, adjustable miter bends, and a spherical mirror in the vacuum vessel with a total round trip transmission loss of 21 dB. The interferometer signal-to-noise ratio is greater than or equal to 50 dB. Utilization of a feed-forward tracking system provides long-term stable operation. The interferometer routinely provides real time feedback control for the gas injection system and a permissive for neutral beam operation.
Date: March 1, 1985
Creator: Efthimion, P.C.; Taylor, G.; Ernst, W.; Goldman, M.; McCarthy, M.; Anderson, H. et al.
Partner: UNT Libraries Government Documents Department

TFTR horizontal high-resolution Bragg x-ray spectrometer

Description: A bent quartz crystal spectrometer of the Johann type with a spectral resolution of lambda/..delta..lambda = 10,000 to 25,000 is used on TFTR to determine central plasma parameters from the spectra of heliumlike and lithiumlike metal impurity ions (Ti, Cr, Fe, and Ni). The spectra are observed along a central radial chord and are recorded by a position sensitive multiwire proportional counter with a spatial resolution of 250. Standard delay-line time-difference readout is employed. The data are histogrammed and stored in 64k of memory providing 128 time groups of 512-channel spectra. The central ion temperature and the toroidal plasma rotation are inferred from the Doppler broadening and Doppler shift of the K lines. The central electron temperature, the distribution of ionization states, and dielectronic recombination rates are obtained from satellite-to-resonance line ratios. The performance of the spectrometer is demonstrated by measurements of the Ti XXI K radiation.
Date: November 1, 1984
Creator: Hill, K.W.; Bitter, M.; Tavernier, M.; Diesso, M.; von Goeler, S.; Johnson, G. et al.
Partner: UNT Libraries Government Documents Department

Results from Langmuir probe measurements in PDX and PLT

Description: Fits to Langmuir probe measurements made near the midplanes of the PDX and PLT tokamaks imply density and electron temperature profiles. In ohmically heated plasmas with either circular or diverted configurations, the edge densities decrease approximately exponentially with e-folding lengths of 1-4cm. Electron temperatures are low (5 to 50 eV) and decrease more gradually than the density profiles in the outer edge.
Date: February 1, 1982
Creator: Budny, R.
Partner: UNT Libraries Government Documents Department

Charge exchange ion temperature measurements during high power neutral beam injection on PLT

Description: A compilation and analysis of charge exchange ion temperature measurements obtained duriang recent high power neutral beam heating experiments on PLT is presented. For titanium gettered discharges using water-cooled carbon limiters (a = 40 cm), PLT produced ion temperatures up to 6.6 keV (T/sub e/ = 3.5 - 4.0 keV) with 2.4 MW-level neutral deuterium injection into low density hydrogen and deuterium plasmas. Over the beam power (P/sub B/ approx. 0.7 - 2.4 MW) and line average electron density (anti n/sub e/ approx. 1.6 - 3.6 x 10/sup 13/ cm/sup -3/) parameter space thus far explored, the ion temperature increase, ..delta..T/sub i/, is observed to scale according to the empirical relation: ..delta..T/sub i/ (keV) = 4.5 +- 0.5 P/sub B/ (MW)/anti n/sub e/(x 10/sup 13/ cm/sup -3/), where anti n/sub e/ is the line average electron density at peak ion temperature.
Date: January 1, 1979
Creator: Medley, S.S. & Davis, S.L.
Partner: UNT Libraries Government Documents Department

Charge exchange analyzer for mass resolved ion temperature measurements on PLT

Description: A five channel, mass resolved, radially scanning charge exchange diagnostic system was calibrated over an energy range of 0.75 less than or equal to E less than or equal to 40 keV and installed recently on PLT. The system provides either passive measurements with facility to correct for neutral density profile effects or active charge exchange diagnostics using a vertically aimed Berkeley ion source which is normally operated at 15 keV, 5 A. This report describes the analyzer and presents typical measurements obtained during high power neutral beam injection heating.
Date: January 1, 1979
Creator: Davis, S.L.; Medley, S.S. & Brusati, M.
Partner: UNT Libraries Government Documents Department