Dual Langmuir-probe array for 3D plasma studies in TORPEX
We have designed and installed a new Langmuir-probe (LP) arraydiagnostic to determine basic three-dimensional (3D) features ofplasmas inTORPEX. Thediagnostic consists of two identical LP arrays, placed on opposite sides of the apparatus, which provide comprehensive coverage of the poloidal cross section at the two differenttoroidal locations. Cross correlation studies of signals from the arrays provide a basic way to extract 3D information from theplasmas, as experiments show. Moreover, the remarkable signal-to-noise performance of the front-endelectronics allows us to follow a different approach in which we combine inform...
Source: Review of Scientific Instruments - November 29, 2016 Category: Physics Authors: M. Baquero-Ruiz, F. Avino, O. Chellai, A. Fasoli, I. Furno, R. Jacquier, F. Manke and S. Patrick Source Type: research
An instrument for measuring scintillators efficiently based on silicon photomultipliers
An instrument used formeasuring multiple scintillators ’ light output and energy resolution was developed. The instrument consisted of a lightsensor array which was composed of 64 discrete SiPMs(SiliconPhotomultipliers), a corresponding individual channel readout electronics system, and a data processing algorithm. A Teflon grid and a large interval between adjacent SiPMs were employed to eliminate the optical cross talk among scintillators. The scintillators ’ light output was obtained by comparing with a reference sample with known light output. Given the SiPM temperature dependency and the difference among each SiPM...
Source: Review of Scientific Instruments - November 29, 2016 Category: Physics Authors: M. J. Yang, Z. M. Zhang, Y. J. Wang, D. W. Li, W. Zhou, H. H. Tang, Y. T. Liu, P. Chai, L. Shuai, X. C. Huang, S. Q. Liu, M. L. Zhu, X. P. Jiang, Y. W. Zhang, T. Li, B. Ma, S. F. Sun, L. Y. Sun, Q. Wang, Z. R. Lu, T. Zhang and L. Wei Source Type: research
Contributed Review: Review of thermal methods for space charge measurement
The spacecharge accumulation phenomenon has garnered great interest over the last two decades because of the increased use ofdirect current in high voltage electrical systems. In this context, a significant relevance has been achieved by the thermal methods, used for solid dielectrics. This paper presents a review of this non-destructive measurement system used for the measurement of spacecharge. The thermal pulse method, the thermal step method, and the laser intensity modulation method are described. For each configuration, the principle of operation, the thicknesses analyzed, and thespatial resolution are described, rep...
Source: Review of Scientific Instruments - November 28, 2016 Category: Physics Authors: A. Imburgia, P. Romano, M. Caruso, F. Viola, R. Miceli, E. Riva Sanseverino, A. Madonia and G. Schettino Source Type: research
Note: Attenuation motion of acoustically levitated spherical rotor
Here we observe theattenuation motion of spherical rotors levitated by near-field acousticradiation force andanalyze the factors that affect the duration time of free rotation. It is found that the rotating speed of freely rotating rotor decreases exponentially with respect to time. The time constant of exponentialattenuation motion depends mainly on the levitation height, the mass of rotor, and the depth of concaveultrasound emitter. Large levitation height, large mass of rotor, and small depth of concave emitter are beneficial to increase the time constant and hence extend the duration time of free rotation. (Source: Rev...
Source: Review of Scientific Instruments - November 23, 2016 Category: Physics Authors: P. L ü, Z. Y. Hong, J. F. Yin, N. Yan, W. Zhai and H. P. Wang Source Type: research
Large-area field-ionization detector for the study of Rydberg atoms
We describe here the development and characterization of a micro-channel plate (MCP) baseddetector designed for the efficient collection anddetection ofRydberg positronium (Ps) atoms for use in a time-of-flight apparatus. The designeddetector collectsRydberg atoms over a large area ( ∼4 times greater than the active area of the MCP), ionizing incident atoms and then collecting and focusing the freedpositrons onto the MCP. Here we discuss the function, design, and optimization of the device. Thedetector has an efficiency forRydberg Ps that is two times larger than that of theγ-rayscintillation detector based scheme it ha...
Source: Review of Scientific Instruments - November 23, 2016 Category: Physics Authors: A. C. L. Jones, A. M. Pi ñeiro, E. E. Roeder, H. J. Rutbeck-Goldman, H. W. K. Tom and A. P. Mills Jr. Source Type: research
High-efficiency integrated readout circuit for single photon avalanche diode arrays in fluorescence lifetime imaging
In recent years, lifetime measurements by means of theTime Correlated Single Photon Counting(TCSPC) technique have led to a significant breakthrough in medical and biological fields. Unfortunately, the many advantages of TCSPC-based approaches come along with the major drawback of a relatively long acquisition time. The exploitation of multiple channels in parallel could in principle mitigate this issue, and at the same time it opens the way to a multi-parameter analysis of the optical signals, e.g., as a function of wavelength or spatial coordinates. TheTCSPC multichannel solutions proposed so far, though, suffer from a t...
Source: Review of Scientific Instruments - November 23, 2016 Category: Physics Authors: G. Acconcia, A. Cominelli, I. Rech and M. Ghioni Source Type: research
Single-phase driven ultrasonic motor using two orthogonal bending modes of sandwiching piezo-ceramic plates
A compactultrasonic motor using sandwiching piezo-ceramic plates was developed, having advantages of low manufacturing costs, simple driving circuit, and high scalability. The stator is composed of twopiezoelectric plates attached to a T-shaped steel body. Two orthogonalbending modes can be excited by driving onepiezoelectric plate and the reversed motion of the rotor can be obtained by driving thepiezoelectric plate on the opposite side. The prototype stator with a size of 15 mm × 2.44 mm × 2 mm, operated at 44.8 kHz, was experimentally characterized, and a maximumtorque of 2 mN m was obtained. Maximum power of 2.3 mW a...
Source: Review of Scientific Instruments - November 21, 2016 Category: Physics Authors: Yuting Ma, Minkyu Choi and Kenji Uchino Source Type: research
A small long-life acoustic transmitter for studying the behavior of aquatic animals
In this study, we developed a small, long-life acoustic transmitter with an approximate length of 24.2 mm, diameter of 5.0 mm, and dry weight of 0.72 g. The transmitter generates a coded acoustic signal at 416.7 kHz with a selectable source level between 159 and 163 dB relative to 1μPa at 1 m, allowing a theoreticaldetection range of up to 500 m. The expected operational lifetime is 1 yr at a pulse rate interval of 15 s. The new technology makes long-term acoustictelemetry studies of small fish possible, and is being deployed for a long-term tracking of juvenile sturgeon. (Source: Review of Scientific Instruments)
Source: Review of Scientific Instruments - November 21, 2016 Category: Physics Authors: J. Lu, Z. D. Deng, H. Li, M. J. Myjak, J. J. Martinez, J. Xiao, R. S. Brown and S. S. Cartmell Source Type: research
Accelerated reconstruction of electrical impedance tomography images via patch based sparse representation
This study proposes an idea to accelerateimage reconstruction ofEIT based on compressive sensing (CS)theory, namely, CSEIT method. The novel CSEIT method reduces the sampling rate through minimizing redundancy inmeasurements, so that detailed information ofreconstruction is not lost. In order to obtain sparse solution, which is the prior condition of signal recovery required by CStheory, a novelimage reconstruction algorithm based on patch-based sparse representation is proposed. By applying the new framework of CSEIT, the data acquisition time, or the sampling rate, is reduced by more than two times, while the accuracy of...
Source: Review of Scientific Instruments - November 21, 2016 Category: Physics Authors: Qi Wang, Zhijie Lian, Jianming Wang, Qingliang Chen, Yukuan Sun, Xiuyan Li, Xiaojie Duan, Ziqiang Cui and Huaxiang Wang Source Type: research
Research on the best measurement situation between optical probe and tissue surfaces in non-invasive detection
Near-infrared spectroscopy is often used for the non-invasive detection of composition in the human body, such as that of blood glucose and haemoglobin, due to its high penetration depth intotissues. Although it is feasible to position the optical probe precisely, contact situation between probe and humantissues is a difficult problem to determine because of physiological tremor and mechanical performance of bio-softtissue. Here, we proposed a novel estimation method for the situation between the optical probe andtissue surfaces based on the dynamic auto-correlation matrix of two-dimensional correlation spectroscopy (2DCOS...
Source: Review of Scientific Instruments - November 21, 2016 Category: Physics Authors: Xuyao Yu, Rong Liu, Hui Yu, Jiao Wang, Jun Wang and Kexin Xu Source Type: research
A precision cryostat design for manual and semi-automated cryo-plunge instruments
Here we describe a bench-top cryostat system tocontrol the temperature ofliquid ethane in a cryo-plunge apparatus designed for biological specimen preparation for electron cryomicroscopy. It comprises a foam insulated Dewar containing acopper cryostat cup, whose temperature iscontrolled via an active feedback system to within 0.1 K. The device can easily be incorporated into existing manual and semi-automatic cryo-plunge instruments that are not equipped with cryogenic temperaturecontrol. Over the course of normal use, we find that using a cryostat is convenient, fast, and does not require special mixtures of cryogens like...
Source: Review of Scientific Instruments - November 21, 2016 Category: Physics Authors: Christopher J. Russo, Steve Scotcher and Martin Kyte Source Type: research
First order reversal curves (FORC) analysis of individual magnetic nanostructures using micro-Hall magnetometry
Alongside the development of artificially createdmagnetic nanostructures, micro-Hall magnetometry has proven to be a versatile tool to obtain high-resolutionhysteresis loop data and access dynamicalproperties. Here we explore the application of First Order Reversal Curves (FORC) —a technique well-established in the field of paleomagnetism for studying grain-size and interaction effects in magnetic rocks—to individual and dipolar-coupled arrays ofmagnetic nanostructures using micro-Hallsensors. A proof-of-principle experiment performed on a macroscopic piece of a floppy disk as a reference sample well known in the liter...
Source: Review of Scientific Instruments - November 21, 2016 Category: Physics Authors: Merlin Pohlit, Paul Eibisch, Maryam Akbari, Fabrizio Porrati, Michael Huth and Jens M üller Source Type: research
Note: Response time characterization of fiber Bragg grating temperature sensor in water medium
Response times offiber Bragg grating(FBG)temperaturesensors are investigated. The response model is established and three types ofsensors, including bare, gold-coated, andceramics packagedFBG, are employed tomeasure their response time under a step simulation. The matchedFBG method is used to obtain the response times. EachFBGsensor ismeasured 5 times and the average values of thesensors are 8.9 ms, 12.3 ms, and 336 ms, respectively. The results are useful fortemperature measurement caring about time characteristic. (Source: Review of Scientific Instruments)
Source: Review of Scientific Instruments - November 18, 2016 Category: Physics Authors: Yuheng Pan, Junfeng Jiang, Kun Liu, Shuang Wang and Tiegen Liu Source Type: research
Note: Wide-range and high-resolution on-chip delay measurement circuit with low supply-voltage sensitivity for SoC applications
This paper presents an on-chip delaymeasurement (OCDM) circuit with a wide delay-measurement range, a high delay-measurement resolution and low supply-voltage sensitivity for efficient detection, and diagnosis in the high-performance system-on-chip (SoC). The proposed cascade-stagemeasurement structure can simultaneously achieve a delay-measurement range of several nanoseconds and a quantization resolution of several picoseconds. The proposed delay-measurement circuit has a high immunity to supply voltage variations without any additionalcalibration or self-biasing circuit. The delay-measurement range is 5.25 ns with 6 ps ...
Source: Review of Scientific Instruments - November 18, 2016 Category: Physics Authors: Duo Sheng and Yu-Chan Hung Source Type: research
Demonstration of low energy proton radiography on an 11-MeV cyclotron
Lens focusedprotonradiograph on thin objects is demonstrated using an 11-MeVproton cyclotron at China Academy of Engineering Physics. Theproton beam exiting from the tested objects is focused onto the image plane by a magnetic lenssystem mitigating image blur caused by multiple Coulombscattering. Both simulations and experiments show that clear images can be obtained with a lenssystem for the objects with thickness up to 2.7 × 10−2 g/cm2 and the error for the arealdensity measurement ismeasured to be less than 2.3%. For the objects with thickness between 2.7 × 10−3 g/cm2 and 2.7 × 10−2 g/cm2, 100 –200μm of spat...
Source: Review of Scientific Instruments - November 18, 2016 Category: Physics Authors: Xiao Ding Zhang, Guo Jun Yang, Yi Ding Li, Tao Wei, Xiaozhong He, Liang Chao Zhao, Zhuo Zhang, Chaofan Ma, Xiaoguo Jiang and Jinshui Shi Source Type: research
