A transmission infrared cell design for temperature-controlled adsorption and reactivity studies on heterogeneous catalysts
A design is presented for a versatile transmission infraredcell that can interface with an external vacuummanifold to undergoin situ gas treatments and receive controlled doses of various adsorbates and probe molecules, allowing characterization of heterogeneous catalyst surfaces in order to identify and quantify active sites and adsorbed surface species. Critical design characteristics include customized temperature control for operation betweencryogenic and elevated temperatures (100 –1000 K) and modified Cajon fittings for operation over a wide pressure range (10−2–103 Torr) that eliminates the complications intro...
Source: Review of Scientific Instruments - October 3, 2016 Category: Physics Authors: Viktor J. Cybulskis, James W. Harris, Yury Zvinevich, Fabio H. Ribeiro and Rajamani Gounder Source Type: research
Initial measurements of plasma current and electron density profiles using a polarimeter/interferometer (POINT) for long pulse operation in EAST (invited)
A double-pass, radially viewing, far-infrared laser-based POlarimeter-INTerferometer (POINT)system utilizing the three-wave technique has been implemented for diagnosing theplasma current andelectron density profiles in the Experimental Advanced SuperconductingTokamak (EAST). POINT has been operated routinely during the most recent experimental campaign and provides continuous 11 chord line-integratedFaraday effect anddensity measurement throughout the entireplasma discharge for all heating schemes and allplasma conditions (including ITER relevant scenario development). Reliability of both the polarimetric and interferomet...
Source: Review of Scientific Instruments - October 3, 2016 Category: Physics Authors: H. Q. Liu, J. P. Qian, Y. X. Jie, W. X. Ding, D. L. Brower, Z. Y. Zou, W. M. Li, H. Lian, S. X. Wang, Y. Yang, L. Zeng, T. Lan, Y. Yao, L. Q. Hu, X. D. Zhang and B. N. Wan Source Type: research
Design of the opacity spectrometer for opacity measurements at the National Ignition Facility
Recent experiments at the Sandia National Laboratory Z facility have called into question models used in calculatingopacity, of importance for modeling stellar interiors. An effort is being made to reproduce these results at the National Ignition Facility (NIF). These experiments require a newX-rayopacityspectrometer (OpSpec) spanning 540 eV –2100 eV with a resolving power E/ΔE> 700. The design of the OpSpec is presented. Photometric calculations based on expectedopacity data are also presented. First use on NIF is expected in September 2016. (Source: Review of Scientific Instruments)
Source: Review of Scientific Instruments - October 3, 2016 Category: Physics Authors: P. W. Ross, R. F. Heeter, M. F. Ahmed, E. Dodd, E. J. Huffman, D. A. Liedahl, J. A. King, Y. P. Opachich, M. B. Schneider and T. S. Perry Source Type: research
A single-mode external cavity diode laser using an intra-cavity atomic Faraday filter with short-term linewidth < 400 kHz and long-term stability of < 1 MHz
We report on the development of adiode laser system - the “Faraday laser” - using an atomicFaraday filter as the frequency-selective element. In contrast to typical external-cavitydiode laser systems which offer tunable output frequency but require additional control systems in order to achieve a stable output frequency, our system only lases at a single frequency, set by the peak transmission frequency of the internal atomicFaraday filter. Our system has both short-term and long-term stability of less than 1 MHz, which is less than the naturallinewidth of alkali-atomic D-lines, making similar systems suitable for use ...
Source: Review of Scientific Instruments - September 30, 2016 Category: Physics Authors: James Keaveney, William J. Hamlyn, Charles S. Adams and Ifan G. Hughes Source Type: research
Note: Characterization and test of a high input impedance RF amplifier for series nanowire detector
We designed a high input impedanceRFamplifier based on Tower Jazz ’s 0.18 μm SiGe BiCMOS process for seriesnanowiredetector. The characterization of its gain and input impedance with a vector network analyzer is described in detail for its specificity. The actual 15 dB gain should be themeasured value subtracts 6 dB, which is easy to be ignored. Its input impedance can be equivalent to 6.7 k Ω ∥ 3.4 pF though fitting themeasurement, whose accuracy is verified. The process ofmeasurement provides a good reference to characterize the similar specialamplifier with unmatched impedance. (Source: Review of Scientific Instruments)
Source: Review of Scientific Instruments - September 30, 2016 Category: Physics Authors: Chao Wan, Yufeng Pei, Zhou Jiang, Lin Kang and Peiheng Wu Source Type: research
A new flexible titanium foil cell for hydrothermal experiments and fluid sampling
This paper describes the design of a flexibletitanium foil cell, as well as its applications in hydrothermalexperiments and in non-contaminating storage of seafloor hydrothermal fluids. A flexible cell constructed totally from puretitanium (Grade 1) can be used in corrosive environment because of the excellent chemical stability and temperature tolerance of the material. Theoretical calculation and finite element analysis of thetitanium foil cell have been conducted to identify its flexibility and deformation mode. Two applications, i.e., hydrothermalreaction and non-contaminating fluid sampling, were introduced subsequent...
Source: Review of Scientific Instruments - September 30, 2016 Category: Physics Authors: Shi-Jun Wu, Min-Jian Cai, Can-Jun Yang and Ke-Wei Li Source Type: research
A single-step lithography system based on an enhanced robotic adhesive dispenser
In the paper, we present a single-steplithography system whereby the robotically controlled micro-extrusion ofresistadhesive onto a substrate surface to directly createresistadhesivepatterns of interest. This system is modified from aroboticadhesive dispenser by shrinking the aperture of the nozzle to a few micrometers aiming to realizepatterns at microscale. From experimental investigation, it is found that working factors including writing speed, working time, and applied pressure can be adopted to conveniently regulate the feature size (the width of the line features and the diameter of the dot features). To test its fu...
Source: Review of Scientific Instruments - September 30, 2016 Category: Physics Authors: Jiyao Xing, Weibin Rong, Ding Sun, Lefeng Wang and Lining Sun Source Type: research
A simple AC calorimeter for specific heat measurement of liquids confined in porous materials: A study of hydrated Vycor
We describe the interfacial Hbond network in the framework of a mean fieldpercolationmodel, to show that at 160 K interfacialwater experiences a transformation from low density amorphousice to a heterogeneous system where transient low and high densitywater patches coexist. The fraction of each species is controlled by the temperature. We identify the largeentropy of the interfacialwater molecules as the cause of this behaviour. (Source: Review of Scientific Instruments)
Source: Review of Scientific Instruments - September 30, 2016 Category: Physics Authors: Marco Bonetti and Jean-Marc Zanotti Source Type: research
Droplet sensing using small and compact high-Q planar resonator based on impedance matching technique
In this paper, we demonstrate the sensing feasibility of the proposed high-Q resonator using a phosphate-buffered salinedroplet atmicrowave frequencies. In the experimental results, the resonant frequency, signal level, and Q-factor of theS21-parameter with and without a 1-μldroplet were changed to about 230 MHz, 32 dB, and 1500, respectively. The resonator system was found to be suitable fordroplet sensing with a small volume due to its small and compact scheme. This resonator system is expected to play an important role indroplet sensing with differentdielectric constants. (Source: Review of Scientific Instruments)
Source: Review of Scientific Instruments - September 30, 2016 Category: Physics Authors: Hee-Jo Lee and Jong-Gwan Yook Source Type: research
Modular time division multiplexer: Efficient simultaneous characterization of fast and slow transients in multiple samples
A modular time divisionmultiplexer (MTDM) device is introduced to enable parallelmeasurement of multiple samples with both fast and slow decay transients spanning from millisecond to month-long time scales. This is achieved by dedicating a single high-speedmeasurement instrument for rapid data collection at the start of a transient, and bymultiplexing a second low-speedmeasurement instrument for slow data collection of several samples in parallel for the later transients. The MTDM is a high-level design concept that can in principlemeasure an arbitrary number of samples, and the low cost implementation here allows up to 16...
Source: Review of Scientific Instruments - September 30, 2016 Category: Physics Authors: Stephan D. Kim, Jiajun Luo, D. Bruce Buchholz, R. P. H. Chang and M. Grayson Source Type: research
The first measurement of plasma density in an ECRIS-like device by means of a frequency-sweep microwave interferometer
The note presents the firstplasma densitymeasurements collected by a novelmicrowaveinterferometer in a compact Electron Cyclotron Resonance Ion Sources (ECRIS). The developed K-band (18.5 ÷ 26.5 GHz)microwaveinterferometry, based on the Frequency-Modulated Continuous-Wave method, has been able to discriminate theplasma signal from the spurious components due to the reflections at theplasma chamber walls, when working in the extreme unfavorable conditionλp≃Lp≃Lc (λp,Lp, andLc being the probing signal wavelength, theplasma dimension and theplasma chamber length, respectively). The note describes the experimental proce...
Source: Review of Scientific Instruments - September 29, 2016 Category: Physics Authors: D. Mascali, G. Torrisi, O. Leonardi, G. Sorbello, G. Castro, L. G. Celona, R. Miracoli, R. Agnello and S. Gammino Source Type: research
Q-band 4-state phase shifter in planar technology: Circuit design and performance analysis
A 30% bandwidthphase shifter with four phase states is designed to be integrated in aradio astronomy receiver. The circuit has two 90 ° out-of-phasemicrowave phase-shifting branches which are combined by Wilkinson power dividers. Each branch is composed of a 180 °phase shifter and aband-pass filter. The 180 °phase shifter is made of cascaded hybrid rings withmicrowave PIN diodes as switchingdevices. The 90 ° phase shift is achieved with the twoband-pass filters. Experimental characterization has shown significant results, with average phase shift values of −90.7°, −181.7°, and 88.5° within the operation band, 35...
Source: Review of Scientific Instruments - September 29, 2016 Category: Physics Authors: E. Villa, J. Cagigas, B. Aja, L. de la Fuente and E. Artal Source Type: research
Quartz crystal microbalance and photoacoustic measurements in dental photocuring
In this study, two techniques,Quartz Crystal Microbalance (QCM) andPhotoacoustic Spectroscopy(PAS), were used to monitor the real-time cure and to obtain theoptical absorptionspectra of resins, respectively. From thePAS measurements, the precise peaks ofabsorption were identified, and were used as the appropriate wavelength of the photocuring light in the QCM monitoring. The combined use of these techniques allows reliable determination of the duration of the phases of physical and chemical changes that occur during photocuring. Two commercial dental resins were tested, and the results confirmed the advantages of usingPAS ...
Source: Review of Scientific Instruments - September 29, 2016 Category: Physics Authors: Marcenilda A. Lima, Ivan N. Bastos and Norberto Cella Source Type: research
Electromagnetic interference reduction design of alternating integrator for EAST
An alternating integrator has been designed for the Experimental Advanced SuperconductingTokamak that is intended for long pulse operation of up to 1000 s. Theelectromagnetic operating environment for the device is so complex that it could affect the performance of the integrator. The new integratorsystem is carefully designed and actualized based on specific reducedelectromagnetic interference requirements, which were formulated based on consideration of processing of the input signals, the isolationproperties, and thecircuit board layout and grounding. The developed integrator shows excellentelectromagnetic compatibility...
Source: Review of Scientific Instruments - September 28, 2016 Category: Physics Authors: D. M. Liu, B. N. Wan, J. Li, Y. Wang, B. Shen, X. Z. Gong and Y. G. He Source Type: research
A comparison of “flat fielding” techniques for x-ray framing cameras
Gain can vary across the active area of anx-ray framingcamera by a factor of 4 (or more!) due to the voltage loss and dispersion associated with pulse transmission in a microstripline-coated microchannel plate. In order to make quantitative measurements, it is consequently important to measure the gain variation ( “flat field”). Moreover, because of electromagnetic cross talk, gain variation depends on specific operational parameters, and ideally a flat field would be obtained at all operating conditions. As part of a collaboration between Lawrence Livermore National Laboratory’s National Ignition Facil ity and the C...
Source: Review of Scientific Instruments - September 28, 2016 Category: Physics Authors: L. R. Benedetti, C. Trosseille, J. P. Holder, K. Piston, D. Hargrove, D. K. Bradley, P. Bell, J. Raimbourg, M. Prat, L. A. Pickworth and S. F. Khan Source Type: research
