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Review of Scientific Instruments

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https://www.readbyqxmd.com/read/28863715/measurement-of-the-velocity-of-neutral-fragments-by-the-correlated-ion-and-neutral-time-of-flight-method-combined-with-velocity-map-imaging
#1
F Berthias, L Feketeová, R Della Negra, T Dupasquier, R Fillol, H Abdoul-Carime, B Farizon, M Farizon, T D Märk
In the challenging field of imaging molecular dynamics, a novel method has been developed and implemented that allows the measurement of the velocity of neutral fragments produced in collision induced dissociation experiments on an event-by-event basis. This has been made possible by combining a correlated ion and neutral time of flight method with a velocity map imaging technique. This new method relies on a multiparametric correlated detection of the neutral and charged fragments from collision induced dissociation on one single detector...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863714/symmetry-consideration-in-zero-loop-area-sagnac-interferometry-at-oblique-incidence-for-detecting-magneto-optic-kerr-effects
#2
X D Zhu
I present a detailed account of a zero loop-area Sagnac interferometer operated at oblique incidence for detecting magneto-optic Kerr effects arising from a magnetized sample. In particular, I describe the symmetry consideration and various optical arrangements available to such an interferometer that enables measurements of magneto-optic effects due to both in-plane and out-of-plane magnetization of the sample with optimizable signal-to-noise ratios.
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863713/scanning-squid-sampler-with-40-ps-time-resolution
#3
Zheng Cui, John R Kirtley, Yihua Wang, Philip A Kratz, Aaron J Rosenberg, Christopher A Watson, Gerald W Gibson, Mark B Ketchen, Kathryn A Moler
Scanning Superconducting QUantum Interference Device (SQUID) microscopy provides valuable information about magnetic properties of materials and devices. The magnetic flux response of the SQUID is often linearized with a flux-locked feedback loop, which limits the response time to microseconds or longer. In this work, we present the design, fabrication, and characterization of a novel scanning SQUID sampler with a 40-ps time resolution and linearized response to periodically triggered signals. Other design features include a micron-scale pickup loop for the detection of local magnetic flux, a field coil to apply a local magnetic field to the sample, and a modulation coil to operate the SQUID sampler in a flux-locked loop to linearize the flux response...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863712/micrometer-thickness-liquid-sheet-jets-flowing-in-vacuum
#4
Gediminas Galinis, Jergus Strucka, Jonathan C T Barnard, Avi Braun, Roland A Smith, Jon P Marangos
Thin liquid sheet jet flows in vacuum provide a new platform for performing experiments in the liquid phase, for example X-ray spectroscopy. Micrometer thickness, high stability, and optical flatness are the key characteristics required for successful exploitation of these targets. A novel strategy for generating sheet jets in vacuum is presented in this article. Precision nozzles were designed and fabricated using high resolution (0.2 μm) 2-photon 3D printing and generated 1.49 ± 0.04 μm thickness, stable, and <λ/20-flat jets in isopropanol under normal atmosphere and under vacuum at 5 × 10(-1) mbar...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863711/measurement-of-contact-angles-of-microscopic-droplets-by-focal-length-method
#5
Daniel Geiger, Kirsten Geiger, Tobias Neckernuss, Othmar Marti, Masoud Amirkhani
We present a method to measure contact angles of microscopic droplets with a conventional microscope that possesses a precision focus adjustment stage. The droplets are modeled as spherical caps that act as lenses. Their focal length is determined by measuring the distance from the substrate surface to the level where a sharp image of the aperture stop is observed. The lens diameter is found by edge detection of a microscope image of the microdroplets. The spherical cap model relates the focal length and diameter of such lenses to the contact angle of the used liquid with known refractive index...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863710/radio-frequency-source-of-a-weakly-expanding-wedge-shaped-xenon-ion-beam-for-contactless-removal-of-large-sized-space-debris-objects
#6
Victor Balashov, Maria Cherkasova, Kirill Kruglov, Arseny Kudriavtsev, Pavel Masherov, Andrey Mogulkin, Vladimir Obukhov, Valentin Riaby, Victoria Svotina
A theoretical-experimental research has been carried out to determine the characteristics of a radio frequency (RF) ion source for the generation of a weakly expanding wedge-shaped xenon ion beam. Such ion beam geometry is of interest as a prototype of an on-board ion injector for contactless "ion shepherding" by service spacecraft to remove large space debris objects from geostationary orbits. The wedge shape of the ion beam increases its range. The device described herein comprises an inductive gas discharge chamber and a slit-type three-electrode ion extraction grid (IEG) unit...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863709/a-surface-science-compatible-epifluorescence-microscope-for-inspection-of-samples-under-ultra-high-vacuum-and-cryogenic-conditions
#7
Christian Marquardt, Alexander Paulheim, Nils Rohbohm, Rudolf Merkel, Moritz Sokolowski
We modified an epi-illumination light microscope and mounted it on an ultra high vacuum chamber for investigating samples used in a surface science experiment. For easy access and bake out, all optical components are placed outside the vacuum and the sample is imaged through a glass window. The microscope can be operated in reflection brightfield or epifluorescence mode to image the sample surface or fluorescent dye molecules adsorbed on it. The homemade sample mounting was made compatible for the use under the microscope; sample temperatures as low as 6 K can be achieved...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863708/false-star-detection-and-isolation-during-star-tracking-based-on-improved-chi-square-tests
#8
Hao Zhang, Yanxiong Niu, Jiazhen Lu, Yanqiang Yang, Guohua Su
The star sensor is a precise attitude measurement device for a spacecraft. Star tracking is the main and key working mode for a star sensor. However, during star tracking, false stars become an inevitable interference for star sensor applications, which may result in declined measurement accuracy. A false star detection and isolation algorithm in star tracking based on improved chi-square tests is proposed in this paper. Two estimations are established based on a Kalman filter and a priori information, respectively...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863707/note-a-two-dimensional-position-sensitive-micro-channel-plate-detector-with-a-cross-connected-pixels-resistive-anode-and-integrated-spectroscopy-amplifiers
#9
Liping Yang, Junliang Liu, Yuezhao Zhang, Wei Wang, Deyang Yu, Xiaoxiao Li, Xin Li, Min Zheng, Baowei Ding, Xiaohong Cai
Based on the charge-division method, a compact detector system for charged particles is constructed. The system consists of a pair of micro-channel plates, a novel two-dimensional position-sensitive cross-connected-pixels resistive anode, and specially designed front-end electronics that can directly drive analog-to-digital converters. The detector is tested with an (241)Am α-source. A position resolution of better than 0.3 mm and a maximum distortion within 0.5 mm in the active dimensions of 100 mm diameter are achieved...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863706/multi-rate-cubature-kalman-filter-based-data-fusion-method-with-residual-compensation-to-adapt-to-sampling-rate-discrepancy-in-attitude-measurement-system
#10
Xiaoting Guo, Changku Sun, Peng Wang
This paper investigates the multi-rate inertial and vision data fusion problem in nonlinear attitude measurement systems, where the sampling rate of the inertial sensor is much faster than that of the vision sensor. To fully exploit the high frequency inertial data and obtain favorable fusion results, a multi-rate CKF (Cubature Kalman Filter) algorithm with estimated residual compensation is proposed in order to adapt to the problem of sampling rate discrepancy. During inter-sampling of slow observation data, observation noise can be regarded as infinite...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863705/real-time-microwave-sensor-system-for-detection-of-polluting-substances-in-pure-water
#11
A L Neves, E Georget, N Cochinaire, P Sabouroux
In the present work, a real-time coaxial sensor for detecting foreign substances in aqueous solutions was developed and tested. This tool, based on a coaxial propagation line for determining the electromagnetic parameters of materials, was updated into a liquid permittivity monitoring sensor of continuous flow. A few solutions of different nature were tested, and while adding a liquid or electrolyte substance, named "pollutant," variations in the base solution were documented. Ethanol and water mixtures were used as reference, while the ability of the system to detect emulsions (such as oil in water solutions) was also evaluated...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863704/power-measurements-and-coupler-optimization-in-inductive-discharges
#12
V A Godyak, B M Alexandrovich
The power absorbed by the plasma is one of the key parameters which defines processes in any plasma source. This power, however, can be very different from the power at the rf power source output or the coupler terminals, which has been used in many publications to characterize the plasma. This article describes how to find the power absorbed by the plasma and the power lost in the coupler and matcher network for inductively coupled plasmas. In addition, several practical coupler configurations to reduce the coupler coil loss and minimize the rf plasma potential are discussed...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863703/the-world-s-smallest-capacitive-dilatometer-for-high-resolution-thermal-expansion-and-magnetostriction-in-high-magnetic-fields
#13
R Küchler, A Wörl, P Gegenwart, M Berben, B Bryant, S Wiedmann
For the characterization of novel quantum phases of matter, it is often required to study materials under multi-extreme conditions, in particular down to very low temperatures and in very high magnetic fields. We developed the world's smallest high-resolution capacitive dilatometer suitable for temperatures down to 10 mK and usage in high magnetic fields up to 37.5 T. Despite the extreme miniaturization, the capacitive dilatometer can resolve length changes down to 0.01 Å. This is an unprecedented resolution in a capacitive dilatometer of this compact size...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863702/development-of-a-wavy-stark-velocity-filter-for-studying-interstellar-chemistry
#14
Kunihiro Okada, Yusuke Takada, Naoki Kimura, Michiharu Wada, Hans A Schuessler
Cold polar molecules are key to both the understanding of fundamental physics and the characterization of the chemical evolution of interstellar clouds. To facilitate such studies over a wide range of temperatures, we developed a new type of Stark velocity filter for changing the translational and rotational temperatures of velocity-selected polar molecules without changing the output beam position. The translational temperature of guided polar molecules can be significantly varied by exchanging the wavy deflection section with one having a different radius of the curvature and a different deflection angle...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863701/new-products
#15
Andreas Mandelis
In order to supplement manufacturers' information, this Department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications.
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863700/fourier-transform-spectral-interferometry-with-non-phase-stable-setups-by-broadband-single-shot-detection-of-fs-and-ps-pulses
#16
Georg Achazi, Andrea Cannizzo
In this paper, we present a novel approach to Fourier transform spectral interferometry based on single-shot detection of broadband pulses. It allows heterodyne detection with non-phase-stabilised setups, which use ps- and fs-pulsed laser sources. This approach can tremendously simplify the implementation of complex techniques such as heterodyne Fourier transform four-wave mixing and pave the way to novel phase-sensitive diagnostics for lasers and optical setups.
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863699/vuv-spectroscopy-in-impurity-injection-experiments-at-kstar-using-prototype-iter-vuv-spectrometer
#17
C R Seon, J H Hong, I Song, J Jang, H Y Lee, Y H An, B S Kim, T M Jeon, J S Park, W Choe, H G Lee, S Pak, M S Cheon, J H Choi, H S Kim, W Biel, P Bernascolle, R Barnsley
The ITER vacuum ultra-violet (VUV) core survey spectrometer has been designed as a 5-channel spectral system so that the high spectral resolving power of 200-500 could be achieved in the wavelength range of 2.4-160 nm. To verify the design of the ITER VUV core survey spectrometer, a two-channel prototype spectrometer was developed. As a subsequent step of the prototype test, the prototype VUV spectrometer has been operated at KSTAR since the 2012 experimental campaign. From impurity injection experiments in the years 2015 and 2016, strong emission lines, such as Kr xxv 15...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863698/full-wave-finite-space-model-of-open-ended-coaxial-line-for-dielectric-spectroscopy-of-liquids
#18
D Jablonskas, S Lapinskas, S Rudys, M Ivanov, J Banys
The physical equipment was built according to the mathematical model and tested. The performance of equipment is demonstrated measuring two known liquids, methanol and isopropanol, up to 40 GHz. The accuracy and sensitivity, and the versatility and ease of manufacturing of the measurement cell are discussed.
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863697/high-bandwidth-and-flexible-tracking-control-for-precision-motion-with-application-to-a-piezo-nanopositioner
#19
Zhao Feng, Jie Ling, Min Ming, Xiao-Hui Xiao
For precision motion, high-bandwidth and flexible tracking are the two important issues for significant performance improvement. Iterative learning control (ILC) is an effective feedforward control method only for systems that operate strictly repetitively. Although projection ILC can track varying references, the performance is still limited by the fixed-bandwidth Q-filter, especially for triangular waves tracking commonly used in a piezo nanopositioner. In this paper, a wavelet transform-based linear time-varying (LTV) Q-filter design for projection ILC is proposed to compensate high-frequency errors and improve the ability to tracking varying references simultaneously...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28863696/x-ray-source-development-for-exafs-measurements-on-the-national-ignition-facility
#20
F Coppari, D B Thorn, G E Kemp, R S Craxton, E M Garcia, Y Ping, J H Eggert, M B Schneider
Extended X-ray absorption Fine Structure (EXAFS) measurements require a bright, spectrally smooth, and broad-band x-ray source. In a laser facility, such an x-ray source can be generated by a laser-driven capsule implosion. In order to optimize the x-ray emission, different capsule types and laser irradiations have been tested at the National Ignition Facility (NIF). A crystal spectrometer is used to disperse the x-rays and high efficiency image plate detectors are used to measure the absorption spectra in transmission geometry...
August 2017: Review of Scientific Instruments
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