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Review of Scientific Instruments

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https://www.readbyqxmd.com/read/27910699/effect-on-measurement-accuracy-of-transillumination-using-sawtooth-shaped-function-optical-signal
#1
Xue Yang, Yajia Hu, Gang Li, Ling Lin
There exist lots of difficulties in optical transillumination of biological tissues, especially, low-level-light detection and low gray-scale resolution could reduce recognition accuracy of differences in tissue. Aiming at the problems, this paper proposes a method for optical transillumination using sawtooth-shaped-function optical signal and frame accumulation technology to explore the spatial information of heterogeneity in the tissue. Sawtooth-shaped-function optical signal combined with frame accumulation technology is applied to realize the low-level-light image detection, where frame accumulation technology improves the signal-to-noise ratio and detection sensitivity, and sawtooth-shaped-function signal improves gray-scale resolution...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910698/laser-induced-fluorescence-measurements-of-axial-velocity-velocity-shear-and-parallel-ion-temperature-profiles-during-the-route-to-plasma-turbulence-in-a-linear-magnetized-plasma-device
#2
S Chakraborty Thakur, K Adriany, J J Gosselin, J McKee, E E Scime, S H Sears, G R Tynan
We report experimental measurements of the axial plasma flow and the parallel ion temperature in a magnetized linear plasma device. We used laser induced fluorescence to measure Doppler resolved ion velocity distribution functions in argon plasma to obtain spatially resolved axial velocities and parallel ion temperatures. We also show changes in the parallel velocity profiles during the transition from resistive drift wave dominated plasma to a state of weak turbulence driven by multiple plasma instabilities...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910697/sensitivity-of-magnetic-field-line-pitch-angle-measurements-to-sawtooth-events-in-tokamaks
#3
J Ko
The sensitivity of the pitch angle profiles measured by the motional Stark effect (MSE) diagnostic to the evolution of the safety factor, q, profiles during the tokamak sawtooth events has been investigated for Korea Superconducting Tokamak Advanced Research (KSTAR). An analytic relation between the tokamak pitch angle, γ, and q estimates that Δγ ∼ 0.1° is required for detecting Δq ∼ 0.05 near the magnetic axis (not at the magnetic axis, though). The pitch angle becomes less sensitive to the same Δq for the middle and outer regions of the plasma (Δγ ∼ 0...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910696/a-new-setup-for-localized-implantation-and-live-characterization-of-kev-energy-multiply-charged-ions-at-the-nanoscale
#4
S Guillous, C Bourin, B Ban D'Etat, A Benyagoub, A Cassimi, C Feierstein, E Gardés, E Giglio, S Girard, C Grygiel, A Houel, H Lebius, A Méry, I Monnet, J-M Ramillon, J Rangama, F Ropars, E Verzeroli, M Viteau, A Delobbe
An innovative experimental setup, PELIICAEN, allowing the modification of materials and the study of the effects induced by multiply charged ion beams at the nanoscale is presented. This ultra-high vacuum (below 5 × 10(-10) mbar) apparatus is equipped with a focused ion beam column using multiply charged ions and a scanning electron microscope developed by Orsay Physics, as well as a scanning probe microscope. The dual beam approach coupled to the scanning probe microscope achieves nanometer scale in situ topological analysis of the surface modifications induced by the ion beams...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910695/understanding-reconstructed-dante-spectra-using-high-resolution-spectroscopy
#5
M J May, J Weaver, K Widmann, G E Kemp, D Thorn, J D Colvin, M B Schneider, A Moore, B E Blue
The Dante is an 18 channel filtered diode array used at the National Ignition Facility (NIF) to measure the spectrally and temporally resolved radiation flux between 50 eV and 20 keV from various targets. The absolute flux is determined from the radiometric calibration of the x-ray diodes, filters, and mirrors and a reconstruction algorithm applied to the recorded voltages from each channel. The reconstructed spectra are very low resolution with features consistent with the instrument response and are not necessarily consistent with the spectral emission features from the plasma...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910694/mhd-marking-using-the-mse-polarimeter-optics-in-ilw-jet-plasmas
#6
S Reyes Cortes, B Alper, D Alves, M Baruzzo, J Bernardo, P Buratti, R Coelho, C Challis, I Chapman, N Hawkes, T C Hender, J Hobirk, E Joffrin
In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910693/characterization-of-compact-toroid-injection-during-formation-translation-and-field-penetration
#7
T Matsumoto, T Roche, I Allfrey, J Sekiguchi, T Asai, H Gota, M Cordero, E Garate, J Kinley, T Valentine, W Waggoner, M Binderbauer, T Tajima
We have developed a compact toroid (CT) injector system for particle refueling of the advanced beam-driven C-2U field-reversed configuration (FRC) plasma. The CT injector is a magnetized coaxial plasma gun (MCPG), and the produced CT must cross the perpendicular magnetic field surrounding the FRC for the refueling of C-2U. To simulate this environment, an experimental test stand has been constructed. A transverse magnetic field of ∼1 kG is established, which is comparable to the C-2U axial magnetic field in the confinement section, and CTs are fired across it...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910692/observation-of-runaway-electrons-by-infrared-camera-in-j-text
#8
R H Tong, Z Y Chen, M Zhang, D W Huang, W Yan, G Zhuang
When the energy of confined runaway electrons approaches several tens of MeV, the runaway electrons can emit synchrotron radiation in the range of infrared wavelength. An infrared camera working in the wavelength of 3-5 μm has been developed to study the runaway electrons in the Joint Texas Experimental Tokamak (J-TEXT). The camera is located in the equatorial plane looking tangentially into the direction of electron approach. The runaway electron beam inside the plasma has been observed at the flattop phase...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910691/compact-ecei-system-with-in-vessel-reflective-optics-for-west
#9
Y B Nam, H K Park, W Lee, G S Yun, M Kim, R Sabot, D Elbeze, P Lotte, J Shen
An electron cyclotron emission imaging (ECEI) diagnostic system for WEST (W Environment for Steady state Tokamak) is under development to study the MHD instabilities affected by tungsten impurities. The system will provide 2-D Te fluctuation images (width × height = ∼18 cm × ∼ 34 cm at low field side and ∼13 cm × ∼ 39 cm at high field side) from a poloidal cross section with high spatial (≤1.7 cm) and temporal (≤2 μs) resolutions. While the key concept and electronic structure are similar to that of prior ECEI systems on other tokamak devices such as KSTAR, DIII-D, or ASDEX-U, part of the imaging optics have to be placed inside the vacuum vessel in order to resolve issues on limited installation space and longer beam path to the detector position...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910690/upgrading-a-high-throughput-spectrometer-for-high-frequency-400-khz-measurements
#10
T Nishizawa, M D Nornberg, D J Den Hartog, D Craig
The upgraded spectrometer used for charge exchange recombination spectroscopy on the Madison Symmetric Torus resolves emission fluctuations up to 400 kHz. The transimpedance amplifier's cutoff frequency was increased based upon simulations comparing the change in the measured photon counts for time-dynamic signals. We modeled each signal-processing stage of the diagnostic and scanned the filtering frequency to quantify the uncertainty in the photon counting rate. This modeling showed that uncertainties can be calculated based on assuming each amplification stage is a Poisson process and by calibrating the photon counting rate with a DC light source to address additional variation...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910689/high-resolution-main-ion-charge-exchange-spectroscopy-in-the-diii-d-h-mode-pedestal
#11
B A Grierson, K H Burrell, C Chrystal, R J Groebner, S R Haskey, D H Kaplan
A new high spatial resolution main-ion (deuterium) charge-exchange spectroscopy system covering the tokamak boundary region has been installed on the DIII-D tokamak. Sixteen new edge main-ion charge-exchange recombination sightlines have been combined with nineteen impurity sightlines in a tangentially viewing geometry on the DIII-D midplane with an interleaving design that achieves 8 mm inter-channel radial resolution for detailed profiles of main-ion temperature, velocity, charge-exchange emission, and neutral beam emission...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910688/first-fast-ion-d-alpha-fida-measurements-and-simulations-on-c-2u
#12
N G Bolte, D Gupta, L Stagner, M Onofri, S Dettrick, E M Granstedt, P Petrov
The first measurements of fast-ion D-alpha (FIDA) radiation have been acquired on C-2U, Tri Alpha Energy's advanced, beam-driven field-reversed configuration (FRC). These measurements are also forward modeled by FIDASIM. This is the first measurement and simulation of FIDA carried out on an FRC topology. FIDA measurements are made of Doppler-shifted Balmer-alpha light from neutralized fast ions using a bandpass filter and photomultiplier tube. One adjustable line-of-sight measured signals at eight locations and eight times during the FRC lifetime over 26 discharges...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910687/a-frequency-tunable-eight-channel-correlation-ece-system-for-electron-temperature-turbulence-measurements-on-the-diii-d-tokamak
#13
C Sung, W A Peebles, C Wannberg, T L Rhodes, X Nguyen, R Lantsov, L Bardóczi
A new eight-channel correlation electron cyclotron emission diagnostic has recently been installed on the DIII-D tokamak to study both turbulent and coherent electron temperature fluctuations under various plasma conditions and locations. This unique system is designed to cover a broad range of operation space on DIII-D (1.6-2.1 T, detection frequency: 72-108 GHz) via four remotely selected local oscillators (80, 88, 96, and 104 GHz). Eight radial locations are measured simultaneously in a single discharge covering as much as half the minor radius...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910686/a-comparison-between-soft-x-ray-and-magnetic-phase-data-on-the-madison-symmetric-torus
#14
P D VanMeter, P Franz, L M Reusch, J S Sarff, D J Den Hartog
The Soft X-Ray (SXR) tomography system on the Madison Symmetric Torus uses four cameras to determine the emissivity structure of the plasma. This structure should directly correspond to the structure of the magnetic field; however, there is an apparent phase difference between the emissivity reconstructions and magnetic field reconstructions when using a cylindrical approximation. The difference between the phase of the dominant rotating helical mode of the magnetic field and the motion of the brightest line of sight for each SXR camera is dependent on both the camera viewing angle and the plasma conditions...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910685/measuring-20-100-t-b-fields-using-zeeman-splitting-of-sodium-emission-lines-on-a-500-ka-pulsed-power-machine
#15
J T Banasek, J T Engelbrecht, S A Pikuz, T A Shelkovenko, D A Hammer
We have shown that Zeeman splitting of the sodium (Na) D-lines at 5890 and 5896 Å can be used to measure the magnetic field (B-field) produced in high current pulsed power experiments. We have measured the B-field next to a return current conductor in a hybrid X-pinch experiment near a peak current of about 500 kA. Na is deposited on the conductor and then is desorbed and excited by radiation from the hybrid X-pinch. The D-line emission spectrum implies B-fields of about 20 T with a return current post of 4 mm diameter or up to 120 T with a return current wire of 0...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910684/a-stretch-compress-scheme-for-a-high-temporal-resolution-detector-for-the-magnetic-recoil-spectrometer-time-mrst
#16
T J Hilsabeck, J A Frenje, J D Hares, C W Wink
A time-resolved detector concept for the magnetic recoil spectrometer for time-resolved measurements of the NIF neutron spectrum is presented. The measurement is challenging due to the time spreading of the recoil protons (or deuterons) as they transit an energy dispersing magnet system. Ions arrive at the focal plane of the magnetic spectrometer over an interval of tens of nanoseconds. We seek to measure the time-resolved neutron spectrum with 20 ps precision by manipulating an electron signal derived from the ions...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910683/publisher-s-note-in-vessel-calibration-of-the-imaging-diagnostics-for-the-real-time-protection-of-the-jet-iter-like-wall-rev-sci-instrum-87-11d430-2016
#17
V Huber, A Huber, D Kinna, I Balboa, S Collins, N Conway, P Drewelow, C F Maggi, G F Matthews, A G Meigs, Ph Mertens, M Price, G Sergienko, S Silburn, A Wynn, K-D Zastrow
No abstract text is available yet for this article.
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910682/publisher-s-note-electron-density-profile-measurements-from-hydrogen-line-intensity-ratio-method-in-versatile-experiment-spherical-torus-rev-sci-instrum-87-11e540-2016
#18
YooSung Kim, Yue-Jiang Shi, Jeong-Hun Yang, SeongCheol Kim, Young-Gi Kim, Jeong-Jeung Dang, Seongmoo Yang, Jungmin Jo, Soo-Ghee Oh, Kyoung-Jae Chung, Y S Hwang
No abstract text is available yet for this article.
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910681/tokamak-independent-software-analysis-suite-for-multi-spectral-line-polarization-mse-diagnostics
#19
S D Scott, R T Mumgaard
A tokamak-independent analysis suite has been developed to process data from Motional Stark Effect (mse) diagnostics. The software supports multi-spectral line-polarization mse diagnostics which simultaneously measure emission at the mse σ and π lines as well as at two "background" wavelengths that are displaced from the mse spectrum by a few nanometers. This analysis accurately estimates the amplitude of partially polarized background light at the σ and π wavelengths even in situations where the background light changes rapidly in time and space, a distinct improvement over traditional "time-interpolation" background estimation...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910680/publisher-s-note-multi-energy-x-ray-detector-calibration-for-t-and-impurity-density-n-measurements-of-mcf-plasmas-rev-sci-instrum-87-11e320-2016
#20
J Maddox, N Pablant, P Efthimion, L Delgado-Aparicio, K W Hill, M Bitter, M L Reinke, M Rissi, T Donath, B Luethi, B Stratton
No abstract text is available yet for this article.
November 2016: Review of Scientific Instruments
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