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Review of Scientific Instruments

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https://www.readbyqxmd.com/read/29960583/laser-driving-and-data-processing-concept-for-mobile-trace-gas-sensing-design-and-implementation
#1
Chang Liu, Béla Tuzson, Philipp Scheidegger, Herbert Looser, Bernhard Bereiter, Manuel Graf, Morten Hundt, Oleg Aseev, Deran Maas, Lukas Emmenegger
High precision mobile sensing of multi-species gases is greatly demanded in a wide range of applications. Although quantum cascade laser absorption spectroscopy demonstrates excellent field-deployment capabilities for gas sensing, the implementation of this measurement technique into sensor-like portable instrumentation still remains challenging. In this paper, two crucial elements, the laser driving and data acquisition electronics, are addressed. Therefore, we exploit the benefits of the time-division multiplexed intermittent continuous wave driving concept and the real-time signal pre-processing capabilities of a commercial System-on-Chip (SoC, Red Pitaya)...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960582/a-new-three-dimensional-nonscanning-laser-imaging-system-based-on-the-illumination-pattern-of-a-point-light-source-array
#2
Wenze Xia, Yayun Ma, Shaokun Han, Yulin Wang, Fei Liu, Yu Zhai
One of the most important goals of research on three-dimensional nonscanning laser imaging systems is the improvement of the illumination system. In this paper, a new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array is proposed. This array is obtained using a fiber array connected to a laser array with each unit laser having independent control circuits. This system uses a point-to-point imaging process, which is realized using the exact corresponding optical relationship between the point-light-source array and a linear-mode avalanche photodiode array detector...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960581/integration-of-fiber-bragg-grating-temperature-sensors-in-plasma-facing-components-of-the-west-tokamak
#3
Y Corre, G Laffont, C Pocheau, R Cotillard, J Gaspar, N Roussel, M Firdaouss, J-L Gardarein, D Guilhem, M Missirlian
Plasma Facing Components (PFC) temperature measurement is mandatory to ensure safe high power and long pulse tokamak operation. IR thermography systems which are widely used in magnetic fusions devices become challenged with the choice of tungsten as a PFC material in the ITER tokamak, mainly due to emissivity uncertainties and reflection issues in a hot environment. Embedded temperature measurements are foreseen to cross-check the IR thermography measurements. Fiber Bragg grating sensors are potentially of great interest for this application because they are immune to electromagnetic interference and allow the measurement of a large number of temperature spots on a single fiber...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960580/a-flow-pulse-adsorption-microcalorimetry-system-for-studies-of-adsorption-processes-on-powder-catalysts
#4
Rui You, Zhaorui Li, Hongyu Zeng, Weixin Huang
A pulse chemisorption system combining a Tian-Calvet microcalorimeter (Setaram Sensys EVO 600) and an automated chemisorption apparatus (Micromeritics Autochem II 2920) was established to accurately measure differential adsorption heats of gas molecules' chemisorption on solid surfaces in a flow-pulse mode. Owing to high sensitivity and high degree of automation in a wide range of temperatures from -100 to 600 °C, this coupled system can present adsorption heats as a function of adsorption temperature and adsorbate coverage...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960579/note-optics-design-of-a-periscope-for-the-kstar-visible-inspection-system-with-mitigated-neutron-damages-on-the-camera
#5
Kyuhang Lee, Jinseok Ko, Hanmin Wi, Jinil Chung, Hyeonjin Seo, Jae Heung Jo
The visible TV system used in the Korea Superconducting Tokamak Advanced Research device has been equipped with a periscope to minimize the damage on its CCD pixels from neutron radiation. The periscope with more than 2.3 m in overall length has been designed for the visible camera system with its semi-diagonal field of view as wide as 30° and its effective focal length as short as 5.57 mm. The design performance of the periscope includes the modulation transfer function greater than 0.25 at 68 cycles/mm with low distortion...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960578/feedback-control-of-local-hotspot-temperature-using-resistive-on-substrate-nanoheater-thermometer
#6
Amun Jarzembski, Sina Hamian, Jeonghoon Yun, Jacob Crossley, Inkyu Park, Mathieu Francoeur, Keunhan Park
This article reports the active control of a local hotspot temperature for accurate nanoscale thermal transport measurement. To this end, we have fabricated resistive on-substrate nanoheater/thermometer (NH/T) devices that have a sensing area of ∼350 nm × 300 nm. Feedback-controlled temporal heating and cooling experiments of the NH/T device confirm that the feedback integral gain plays a dominant role in device's response time for various setpoint temperatures. To further verify the integration of the feedback controller with the NH/T devices, a local tip-induced cooling experiment is performed by scanning a silicon tip over the hotspot area in an atomic force microscope platform...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960577/the-software-defined-fast-post-processing-for-gem-soft-x-ray-diagnostics-in-the-tungsten-environment-in-steady-state-tokamak-thermal-fusion-reactor
#7
Rafał Dominik Krawczyk, Tomasz Czarski, Paweł Linczuk, Andrzej Wojeński, Piotr Kolasiński, Michał Gąska, Maryna Chernyshova, Didier Mazon, Axel Jardin, Philippe Malard, Krzysztof Poźniak, Grzegorz Kasprowicz, Wojciech Zabołotny, Ewa Kowalska-Strzęciwilk, Karol Malinowski
This article presents a novel software-defined server-based solutions that were introduced in the fast, real-time computation systems for soft X-ray diagnostics for the WEST (Tungsten Environment in Steady-state Tokamak) reactor in Cadarache, France. The objective of the research was to provide a fast processing of data at high throughput and with low latencies for investigating the interplay between the particle transport and magnetohydrodynamic activity. The long-term objective is to implement in the future a fast feedback signal in the reactor control mechanisms to sustain the fusion reaction...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960576/two-dimensional-displacement-measurement-based-on-two-parallel-gratings
#8
Peipei Wei, Xi Lu, Decheng Qiao, Limin Zou, Xiangdong Huang, Jiubin Tan, Zhengang Lu
In this paper, a two-dimensional (2-D) planar encoder based on two parallel gratings, which includes a scanning grating and scale grating, is presented. The scanning grating is a combined transmission rectangular grating comprised of a 2-D grating located at the center and two one-dimensional (1-D) gratings located at the sides. The grating lines of the two 1-D gratings are perpendicular to each other and parallel with the 2-D grating lines. The scale grating is a 2-D reflective-type rectangular grating placed in parallel with the scanning grating, and there is an angular difference of 45° between the grating lines of the two 2-D gratings...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960575/the-high-energy-x-ray-diffraction-and-scattering-beamline-at-the-canadian-light-source
#9
A Gomez, G Dina, S Kycia
The optical design for the high-energy x-ray diffraction and scattering beamline of the Brockhouse sector at the Canadian Light Source is described. The design is based on a single side-bounce silicon focusing monochromator that steers the central part of a high-field permanent magnet wiggler beam into the experimental station. Two different configurations are proposed: a higher energy resolution with vertical focusing and a lower energy resolution with horizontal and vertical focusing. The monochromator will have the possibility of mounting three crystals: one crystal optimized for 35 keV that focuses in the horizontal and vertical directions using reflection (1,1,1) and two other crystals both covering the energies above 40 keV: one with only vertical focusing and another one with horizontal and vertical focusing...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960574/polarimetric-microscopy-for-optical-control-and-high-precision-measurement-of-valley-polarization
#10
SeokJae Yoo, Q-Han Park
Two-dimensional transition metal dichalcogenides (2D TMDCs) have two degenerate energy valleys in their Brillouin zone, and these two separate valleys can be used as an information carrier in optoelectronic devices. Circularly polarized optical pumping can selectively populate a single valley, resulting in direct band transitions at the populated valley and associated circularly polarized photoluminescence (PL) emission. However, the birefringence and linear dichroism in optical microscopes can not only distort the circular polarization states of optical pumping but also contaminate experimentally derived information about the polarization states of valley-polarized PL signals...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960573/on-the-scattering-correction-of-fast-ion-d-alpha-signals-on-nstx-u
#11
G Z Hao, W W Heidbrink, D Liu, L Stagner, M Podestà, A Bortolon
Analysis of fast-ion D-alpha (FIDA) data on National Spherical Torus Experiment-Upgrade (NSTX-U) shows that the cold Dα line contaminates the FIDA baseline. The scattered light is comparable to the FIDA emission. A scattering correction is required to extract the FIDA signal. Two methods that relate the scattered light contamination to the intensity of the cold Dα line are employed. One method uses laboratory measurements with a calibration lamp; the other method uses data acquired during plasma operation and singular value decomposition analysis...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960572/design-and-validation-of-an-advanced-entrained-flow-reactor-system-for-studies-of-rapid-solid-biomass-fuel-particle-conversion-and-ash-formation-reactions
#12
David R Wagner, Per Holmgren, Nils Skoglund, Markus Broström
The design and validation of a newly commissioned entrained flow reactor is described in the present paper. The reactor was designed for advanced studies of fuel conversion and ash formation in powder flames, and the capabilities of the reactor were experimentally validated using two different solid biomass fuels. The drop tube geometry was equipped with a flat flame burner to heat and support the powder flame, optical access ports, a particle image velocimetry (PIV) system for in situ conversion monitoring, and probes for extraction of gases and particulate matter...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960571/singular-value-decomposition-based-impulsive-noise-reduction-in-multi-frequency-phase-sensitive-demodulation-of-electrical-impedance-tomography
#13
Zhenhua Hao, Ziqiang Cui, Shihong Yue, Huaxiang Wang
As an important means in electrical impedance tomography (EIT), multi-frequency phase-sensitive demodulation (PSD) can be viewed as a matched filter for measurement signals and as an optimal linear filter in the case of Gaussian-type noise. However, the additive noise usually possesses impulsive noise characteristics, so it is a challenging task to reduce the impulsive noise in multi-frequency PSD effectively. In this paper, an approach for impulsive noise reduction in multi-frequency PSD of EIT is presented...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960570/erratum-invited-review-article-hands-on-laser-driven-ion-acceleration-a-primer-for-laser-driven-source-development-and-potential-applications-rev-sci-instrum-87-071101-2016
#14
Jörg Schreiber, Paul R Bolton, Katia Parodi
No abstract text is available yet for this article.
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960569/photon-doppler-velocimetry-measurements-of-transverse-surface-velocities
#15
C R Johnson, J W LaJeunesse, P A Sable, A Dawson, A Hatzenbihler, J P Borg
The goal of this work was to develop a technique for making transverse surface velocity measures utilizing Photon Doppler Velocimetry (PDV). Such a task is achieved by transmitting light and collecting Doppler-shifted light at an angle relative to the normal axis, where measured velocities are representative of a component of the transverse velocity. Because surface characteristics have an intrinsic effect on light scatter, different surface preparations were explored to direct reflectivity, including diffusion by means of sandpapering, or increasing retroreflectivity by coating with microspheres, milling v-cuts, and electrochemically etching grooves...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960568/measurement-of-doping-profiles-by-a-contactless-method-of-ir-reflectance-under-grazing-incidence
#16
Jakub Holovský, Zdeněk Remeš, Aleš Poruba, Daniel Franta, Brianna Conrad, Lucie Abelová, David Bušek
An improved contactless method of the measurement and evaluation of charge carrier profiles in polished wafers by infrared reflectance was developed. The sensitivity of optical reflectance to the incidence angle was theoretically analyzed. A grazing incident angle enhances sensitivity to doping profile parameters. At the same time, the sensitivity to experimental errors sharply increases around the Brewster angle. Therefore, the optimal angle of 65° was chosen. Experimental errors such as unintentional polarization of the measurement beam were minimized by division by reference spectra taken on an undoped sample and further by normalization to a fixed value in the region of 4000 cm-1 to 7000 cm-1 ...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960567/note-effect-of-the-parasitic-forced-vibration-in-an-atom-gravimeter
#17
Le-Le Chen, Qin Luo, Heng Zhang, Xiao-Chun Duan, Min-Kang Zhou, Zhong-Kun Hu
The vibration isolator usually plays an important role in atom interferometry gravimeters to improve their sensitivity. We show that the parasitic forced vibration of the Raman mirror, which is induced by external forces acting on the vibration isolator, can cause a bias in atom gravimeters. The mechanism of how this effect induces an additional phase shift in our interferometer is analyzed. Moreover, modulation experiments are performed to measure the dominant part of this effect, which is caused by the magnetic force between the passive vibration isolator and the coil of the magneto-optic trap...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960566/hexapod-hall-scanner-for-high-resolution-large-area-magnetic-imaging
#18
G K Perkins, M Kustov, E Lovell, M V Pettifer, L F Cohen
We demonstrate a six-axis scanning imaging apparatus using piezo bending actuators with a large scan range. The six axes of motion of the bending actuators together with the coupling mechanism to the translation stage allow complete control of the sensor position and orientation over the scanning surface, which is ideal for the use of planar sensors such as Hall devices. In particular, the design allows for in situ correction of the probe tilt angle so that the sensor distance to sample surface can be minimized...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960565/readout-models-for-bafbr-0-85-i-0-15-eu-image-plates
#19
M Stoeckl, A A Solodov
The linearity of the photostimulated luminescence process makes repeated image-plate scanning a viable technique to extract a more dynamic range. In order to obtain a response estimate, two semi-empirical models for the readout fading of an image plate are introduced; they relate the depth distribution of activated photostimulated luminescence centers within an image plate to the recorded signal. Model parameters are estimated from image-plate scan series with BAS-MS image plates and the Typhoon FLA 7000 scanner for the hard x-ray image-plate diagnostic over a collection of experiments providing x-ray energy spectra whose approximate shape is a double exponential...
June 2018: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29960564/coherent-synchrotron-radiation-monitor-for-microbunching-instability-in-xfel
#20
Jun Ho Ko, Gyujin Kim, Changbum Kim, Heung-Sik Kang, In Soo Ko
The microbunching instability is an important issue in an X-ray Free Electron Laser (XFEL). The intensity of the Free Electron Laser (FEL) can be reduced significantly by the microbunching instability so that the laser heater is widely used to reduce it. In the X-ray Free Electron Laser of the Pohang Accelerator Laboratory (PAL-XFEL), to directly monitor the microbunching instability, a visible charge coupled device camera was included into the coherent radiation monitor which uses a pyroelectric detector. It enabled us to measure the microbunching instability more clearly and optimize the FEL lasing in the PAL-XFEL...
June 2018: Review of Scientific Instruments
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