RSI Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter UniPHY Group iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

Oct 2011

Volume 82, Issue 10, Articles (10xxxx)

Issue Cover Spotlight Figure

Rev. Sci. Instrum. 82, 101101 (2011); http://dx.doi.org/10.1063/1.3652857 (44 pages)

G. Cella and A. Giazotto

Aerial view of the VIRGO detector, with details (from left to right) of the seismic attenuation system, the mirrors and the vacuum system. In the rightmost position, a detail of an optical setup which can provide light in a squeezed state. This can be used to improve the detector sensitivity.

Enlarge Image | Read More
Page 1 of 3 Pages Next Page | Jump to Page
back to top
RSS Feeds

Invited Review Article: Interferometric gravity wave detectors

G. Cella and A. Giazotto

Rev. Sci. Instrum. 82, 101101 (2011); http://dx.doi.org/10.1063/1.3652857 (44 pages)

Online Publication Date: 25 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A direct detection of gravitational waves is still lacking today. A network of several earthbound interferometric detectors is currently operating with a continuously improving sensitivity. The window of interest for observation has a lower cut off in the frequency domain below some tens of hertz, determined by the effect of seismic motion. For larger frequencies, the sensitivity is limited by thermal effects below few hundreds of hertz and by the quantum nature of light above that value. Each of these sources of noise pose a big technological challenge to experimentalists, and there are big expectations for the next generation of detectors. A reduction of thermal effects by at least one order of magnitude will be obtained with new and carefully designed materials. At that point the quantum nature of light will become an issue, and the use of quantum non-demolition techniques will become mandatory. In this review, we discuss interferometric detection of gravitational waves from an instrumental point of view. We try to address conceptually important issues with an audience of non-experts in mind. A particular emphasis is given to the description of the current limitations and to the perspectives of beating them.
Show PACS
07.60.Ly Interferometers
95.55.Ym Gravitational radiation detectors; mass spectrometers; and other instrumentation and techniques
04.80.Nn Gravitational wave detectors and experiments
04.30.-w Gravitational waves
back to top
RSS Feeds
back to top Optics; Atoms and Molecules; Spectroscopy; Photon Detectors

A sample holder for soft x-ray absorption spectroscopy of liquids in transmission mode

Simon Schreck, Gianina Gavrila, Christian Weniger, and Philippe Wernet

Rev. Sci. Instrum. 82, 103101 (2011); http://dx.doi.org/10.1063/1.3644192 (10 pages)

Online Publication Date: 4 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A novel sample holder for soft x-ray absorption spectroscopy of liquids in transmission mode based on sample cells with x-ray transparent silicon nitride membranes is introduced. The sample holder allows for a reliable preparation of ultrathin liquid films with an adjustable thickness in the nm–μm range. This enables measurements of high quality x-ray absorption spectra of liquids in transmission mode, as will be shown for the example of liquid H2O, aqueous solutions of 3d-transition metal ions and alcohol-water mixtures. The fine structure of the x-ray absorption spectra is not affected by the sample thickness. No effects of the silicon nitride membranes were observed in the spectra. It is shown how an inhomogeneous thickness of the sample affects the spectra and how this can be avoided.
Show PACS
78.70.Dm X-ray absorption spectra
06.60.Ei Sample preparation (including design of sample holders)
68.15.+e Liquid thin films

A portable fluorescence detector for fast ultra trace detection of explosive vapors

Yunhong Xin, Gang He, Qi Wang, and Yu Fang

Rev. Sci. Instrum. 82, 103102 (2011); http://dx.doi.org/10.1063/1.3642661 (8 pages)

Online Publication Date: 4 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper developed a portable detector based on a specific material-based fluorescent sensing film for an ultra trace detection of explosives, such as 2,4,6-trinitrotoluene (TNT) or its derivate 2,4-dinitrotoluene (DNT), in ambient air or on objects tainted by explosives. The fluorescent sensing films are based on single-layer chemistry and the signal amplification effect of conjugated polymers, which exhibited higher sensitivity and shorter response time to TNT or DNT at their vapor pressures. Due to application of the light emitting diode and the solid state photomultiplier and the cross-correlation-based circuit design technology, the device has the advantages of low-power, low-cost, small size, and an improved signal to noise ratio. The results of the experiments showed that the detector can real-time detect and identify of explosive vapors at extremely low levels; it is suitable for the identification of suspect luggage, forensic analyses, or battlefields clearing.
Show PACS
82.80.Dx Analytical methods involving electronic spectroscopy
89.20.Dd Military technology and weapons systems; arms control
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing

Field-programmable gate array based locking circuit for external cavity diode laser frequency stabilization

Arne Schwettmann, Jonathon Sedlacek, and James P. Shaffer

Rev. Sci. Instrum. 82, 103103 (2011); http://dx.doi.org/10.1063/1.3646477 (6 pages)

Online Publication Date: 7 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a locking circuit for external cavity diode lasers implemented on a field-programmable gate array (FPGA). The main advantages over traditional non-FPGA-based locking circuits are rapid reconfigurability without any soldering and a friendly user interface. We characterize the lock quality by measuring the linewidth of a locked laser using electromagnetically induced transparency in a Rb vapor cell.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.Fc Modulation, tuning, and mode locking
07.60.-j Optical instruments and equipment

Fully automated spatially resolved reflectance spectrometer for the determination of the absorption and scattering in turbid media

F. Foschum, M. Jäger, and A. Kienle

Rev. Sci. Instrum. 82, 103104 (2011); http://dx.doi.org/10.1063/1.3648120 (10 pages)

Online Publication Date: 13 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We describe a fully automated setup which is based on measurements of the spatially resolved reflectance for the determination of the reduced scattering and absorption coefficients in semi-infinite turbid media. The sample is illuminated with a xenon light source in combination with a monochromator enabling the scan of the wavelength from 450 nm to 950 nm. Reflected light from the sample is detected with a CCD camera providing a high spatial resolution. The essential steps for signal processing including, e.g., the consideration of the optical transfer function and the correct treatment of the background subtraction, are presented. The solutions of the diffusion theory and of the radiative transfer theory are investigated regarding the exact detection and illumination geometry. Systematic errors caused by using the different theories for fitting the optical parameters are characterized. The system was validated using liquid phantoms which contain Intralipid 20% and ink, and the measurement range of the system is specified. Further, we carefully characterized the optical properties of Intralipid 20% in the wavelength range between 450 nm and 950 nm.
Show PACS
07.60.-j Optical instruments and equipment
42.25.Bs Wave propagation, transmission and absorption
42.25.Fx Diffraction and scattering

A magnetic-bottle multi-electron-ion coincidence spectrometer

Akitaka Matsuda, Mizuho Fushitani, Chien-Ming Tseng, Yasumasa Hikosaka, John H. D. Eland, and Akiyoshi Hishikawa

Rev. Sci. Instrum. 82, 103105 (2011); http://dx.doi.org/10.1063/1.3648133 (6 pages)

Online Publication Date: 19 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A novel multi-electron-ion coincidence spectrometer developed on the basis of a 1.5 m-long magnetic-bottle electron spectrometer is presented. Electrons are guided by an inhomogeneous magnetic field to a detector at the end of the flight tube, while a set of optics is used to extract counterpart ions to the same detector, by a pulsed inhomogeneous electric field. This setup allows ion detection with high mass resolution, without impairing the high collection efficiency for electrons. The performance of the coincidence spectrometer was tested with double ionization of carbon disulfide, CS2 →  CS 22+ + e− + e−, in ultrashort intense laser fields (2.8 × 1013 W/cm2, 280 fs, 1030 nm) to clarify the electron correlation below the rescattering threshold.
Show PACS
07.81.+a Electron and ion spectrometers
29.40.-n Radiation detectors

Characterization of near-terahertz complementary metal-oxide semiconductor circuits using a Fourier-transform interferometer

D. J. Arenas, Dongha Shim, D. I. Koukis, Eunyoung Seok, D. B. Tanner, and Kenneth K. O

Rev. Sci. Instrum. 82, 103106 (2011); http://dx.doi.org/10.1063/1.3647223 (6 pages)

Online Publication Date: 24 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical methods for measuring of the emission spectra of oscillator circuits operating in the 400–600 GHz range are described. The emitted power from patch antennas included in the circuits is measured by placing the circuit in the source chamber of a Fourier-transform interferometric spectrometer. The results show that this optical technique is useful for measuring circuits pushing the frontier in operating frequency. The technique also allows the characterization of the circuit by measuring the power radiated in the fundamental and in the harmonics. This capability is useful for oscillator architectures designed to cancel the fundamental and use higher harmonics. The radiated power was measured using two techniques: direct measurement of the power by placing the device in front of a bolometer of known responsivity, and by comparison to the estimated power from blackbody sources. The latter technique showed that these circuits have higher emission than blackbody sources at the operating frequencies, and, therefore, offer potential spectroscopy applications.
Show PACS
07.60.Ly Interferometers
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques

Simultaneous time and wavelength resolved spectroscopy under two-colour near infrared and terahertz excitation

J. Bhattacharyya, M. Wagner, S. Zybell, S. Winnerl, D. Stehr, M. Helm, and H. Schneider

Rev. Sci. Instrum. 82, 103107 (2011); http://dx.doi.org/10.1063/1.3653394 (7 pages) | Cited 2 times

Online Publication Date: 25 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Time and wavelength resolved spectroscopy requires optical sources emitting very short pulses and a fast detection mechanism capable of measuring the evolution of the output spectrum as a function of time. We use table-top Ti:sapphire lasers and a free-electron laser (FEL) emitting ps pulses as excitation sources and a streak camera coupled to a spectrometer for detection. One of the major aspects of this setup is the synchronization of pulses from the two lasers which we describe in detail. Optical properties of the FEL pulses are studied by autocorrelation and electro-optic sampling measurements. We discuss the advantages of using this setup to perform photoluminescence quenching in semiconductor quantum wells and quantum dots. Carrier redistribution due to pulsed excitation in these heterostructures can be investigated directly. Sideband generation in quantum wells is also studied where the intense FEL pulses facilitate the detection of the otherwise weak nonlinear effect.
Show PACS
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy
78.55.Cr III-V semiconductors
84.40.-x Radiowave and microwave (including millimeter wave) technology
07.60.-j Optical instruments and equipment

A line-imaging velocity interferometer technique for shock diagnostics without x-ray preheat limitation

Feng Wang, Xiaoshi Peng, Shenye Liu, Tao Xu, Lusheng Mei, Xiaohua Jiang, and Yongkun Ding

Rev. Sci. Instrum. 82, 103108 (2011); http://dx.doi.org/10.1063/1.3653800 (5 pages)

Online Publication Date: 25 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A study was conducted with a line-imaging velocity interferometer on sandwich targets at the Shen Guang-III prototype laser facility in China, with the goal of eliminating the preheat effect. A sandwich target structure was used to reduce the x-ray preheat limitation (radiation temperature ∼170 eV) in a radiative drive shock experiment. With a thick ablator, the preheat effect appeared before the shock arrived at the window. After adding a shield layer of high-Z material on the ablator, x-rays which penetrated the ablator were so weak that the blank-out effect could not be measured. This experiment indicates that the sandwich target may provide a valuable technique in experiments such as equation of state and shock timing for inertial confinement fusion studies.
Show PACS
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.25.Kn Thermodynamics of plasmas
52.35.Tc Shock waves and discontinuities
52.38.Mf Laser ablation
52.57.-z Laser inertial confinement

Research on the fiber Bragg grating sensor for the shock stress measurement

Xiangyang Deng, Guanghua Chen, Qixian Peng, Zeren Li, Jianhua Meng, and Jun Liu

Rev. Sci. Instrum. 82, 103109 (2011); http://dx.doi.org/10.1063/1.3648123 (4 pages)

Online Publication Date: 26 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A fiber Bragg grating (FBG) sensor with an unbalanced Mach-Zehnder fiber interferometer for the shock stress measurement is proposed and demonstrated. An analysis relationship between the shock stress and the central reflection wavelength shift of the FBG is firstly derived. In this sensor, the optical path difference of the unbalanced Mach-Zehnder fiber interferometer is ∼3.1 mm and the length of the FBG is 2 mm. An arctangent function reduction method, which can avoid sine function's insensitive zone where the shock stress measurement has a reduced accuracy, is presented. A shock stress measurement of water driven by one stage gun (up to 1.4 GPa), with good theoretical accuracy (∼10%), is launched.
Show PACS
42.81.Pa Sensors, gyros
07.10.-h Mechanical instruments and equipment
07.60.Ly Interferometers
07.60.Vg Fiber-optic instruments

Laser-locked, continuously tunable high resolution cavity ring-down spectrometer

H. Pan (潘虎), C.-F. Cheng (程存峰), Y. R. Sun (孙羽), B. Gao (高波), A.-W. Liu (刘安雯), and S.-M. Hu (胡水明)

Rev. Sci. Instrum. 82, 103110 (2011); http://dx.doi.org/10.1063/1.3655445 (4 pages)

Online Publication Date: 27 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A continuous-wave cavity ring-down spectrometer with sub-MHz precision has been built using the sideband of a frequency stabilized laser as the tunable light source. The sideband is produced by passing the carrier laser beam through an electro-optic modulator (EOM) and then selected by a short etalon on resonance. The carrier laser frequency is locked to a longitude mode of a thermo-stabilized Fabry-Perot interferometer (FPI) with a long-term absolute frequency stability of 0.2 MHz (5 × 10−10). Broad and precise spectral scanning is accomplished, respectively, by selecting a different longitudinal mode of the FPI and by tuning the radio-frequency driving the EOM. The air broadened water absorption line at 12 321 cm−1 was studied to test the performance of the spectrometer.
Show PACS
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.79.Hp Optical processors, correlators, and modulators
07.60.Ly Interferometers

Combined optical and acoustical method for determination of thickness and porosity of transparent organic layers below the ultra-thin film limit

K. B. Rodenhausen, T. Kasputis, A. K. Pannier, J. Y. Gerasimov, R. Y. Lai, M. Solinsky, T. E. Tiwald, H. Wang, A. Sarkar, T. Hofmann, N. Ianno, and M. Schubert

Rev. Sci. Instrum. 82, 103111 (2011); http://dx.doi.org/10.1063/1.3653880 (10 pages)

Online Publication Date: 28 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Analysis techniques are needed to determine the quantity and structure of materials composing an organic layer that is below an ultra-thin film limit and in a liquid environment. Neither optical nor acoustical techniques can independently distinguish between thickness and porosity of ultra-thin films due to parameter correlation. A combined optical and acoustical approach yields sufficient information to determine both thickness and porosity. We describe application of the combinatorial approach to measure single or multiple organic layers when the total layer thickness is small compared to the wavelength of the probing light. The instrumental setup allows for simultaneous in situ spectroscopic ellipsometry and quartz crystal microbalance dynamic measurements, and it is combined with a multiple-inlet fluid control system for different liquid solutions to be introduced during experiments. A virtual separation approach is implemented into our analysis scheme, differentiated by whether or not the organic adsorbate and liquid ambient densities are equal. The analysis scheme requires that the film be assumed transparent and rigid (non-viscoelastic). We present and discuss applications of our approach to studies of organic surfactant adsorption, self-assembled monolayer chemisorption, and multiple-layer target DNA sensor preparation and performance testing.
Show PACS
78.20.hb Piezo-optical, elasto-optical, acousto-optical, and photoelastic effects
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
68.43.Mn Adsorption kinetics
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.66.Qn Polymers; organic compounds
87.14.gk DNA
back to top Particle Sources, Optics and Acceleration; Particle Detectors

Detection of atomic and molecular mega-electron-volt projectiles using an x-ray charged coupled device camera

M. Chabot, G. Martinet, K. Béroff, T. Pino, S. Bouneau, B. Genolini, X. Grave, K. Nguyen, C. le Gailliard, P. Rosier, G. Féraud, H. Friha, and B. Villier

Rev. Sci. Instrum. 82, 103301 (2011); http://dx.doi.org/10.1063/1.3640411 (9 pages)

Online Publication Date: 6 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We show that an x-ray charge coupled device (CCD) may be used as a particle detector for atomic and molecular mega-electron-volt (MeV) projectiles of around a few hundred keV per atomic mass unit. For atomic species, spectroscopic properties in kinetic energy measurements (i.e., linearity and energy resolution) are found to be close to those currently obtained with implanted or surface barrier silicon particle detectors. For molecular species, in order to increase the maximum kinetic energy detection limit, we propose to put a thin foil in front of the CCD. This foil breaks up the molecules into atoms and spreads the charges over many CCD pixels and therefore avoiding saturation effects. This opens new perspectives in high velocity molecular dissociation studies with accelerator facilities.
Show PACS
07.77.Gx Atomic and molecular beam sources and detectors
42.79.Pw Imaging detectors and sensors
29.40.-n Radiation detectors

Efficient spin resolved spectroscopy observation machine at Hiroshima Synchrotron Radiation Center

Taichi Okuda, Koji Miyamaoto, Hirokazu Miyahara, Kenta Kuroda, Akio Kimura, Hirofumi Namatame, and Masaki Taniguchi

Rev. Sci. Instrum. 82, 103302 (2011); http://dx.doi.org/10.1063/1.3648102 (7 pages)

Online Publication Date: 21 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Highly efficient spin- and angle-resolved photoelectron spectrometer named ESPRESSO (Efficient SPin REsolved SpectroScopy Observation) machine has been developed at the beamline BL-9B in Hiroshima Synchrotron Radiation Center. Combination of high-resolution hemispherical electron analyzer and the high-efficient spin detector based on very low energy electron diffraction by the ferromagnetic target makes the high-energy resolution and angular resolution compatible with spin- and angle-resolved photoemission (SARPES) measurement. 7.5 meV in energy and ±0.18° in angular resolution have been achieved with spin resolution. The ESPRESSO machine, combination of quick energy-band dispersion measurement and Fermi surface mapping by two-dimensional electron detector for the spin integrated ARPES and the high-efficient spin analysis by the efficient spin detector realizes the comprehensive investigation of spin electronic structure of materials.
Show PACS
79.60.-i Photoemission and photoelectron spectra
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)

The response of CR-39 nuclear track detector to 1–9 MeV protons

N. Sinenian, M. J. Rosenberg, M. Manuel, S. C. McDuffee, D. T. Casey, A. B. Zylstra, H. G. Rinderknecht, M. Gatu Johnson, F. H. Séguin, J. A. Frenje, C. K. Li, and R. D. Petrasso

Rev. Sci. Instrum. 82, 103303 (2011); http://dx.doi.org/10.1063/1.3653549 (7 pages) | Cited 2 times

Online Publication Date: 28 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The response of CR-39 nuclear track detector (TasTrak®) to protons in the energy range of 0.92–9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. Effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather than the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.
Show PACS
29.40.Gx Tracking and position-sensitive detectors
back to top Nuclear Physics, Fusion and Plasmas
Author Select

Edge and core Thomson scattering systems and their calibration on the ASDEX Upgrade tokamak

B. Kurzan and H. D. Murmann

Rev. Sci. Instrum. 82, 103501 (2011); http://dx.doi.org/10.1063/1.3643771 (6 pages)

Online Publication Date: 4 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A new 10 channel Thomson scattering (TS) system was installed on the ASDEX Upgrade tokamak to measure radial profiles of electron density and temperature at the plasma edge with high radial resolution. Together with the already existing TS system, which is now used for the core plasma, electron density and temperature profiles extending from the edge to the core are now obtained in a single discharge. The TS systems are relatively calibrated by an optical parametric oscillator
Show PACS
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.55.Fa Tokamaks, spherical tokamaks

Techniques for the measurement of disruption halo currents in the National Spherical Torus Experiment

S. P. Gerhardt, E. Fredrickson, L. Guttadora, R. Kaita, H. Kugel, J. Menard, and H. Takahashi

Rev. Sci. Instrum. 82, 103502 (2011); http://dx.doi.org/10.1063/1.3642618 (9 pages)

Online Publication Date: 6 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper describes techniques for measuring halo currents, and their associated toroidal peaking, in the National Spherical Torus Experiments [M. Ono et al., Nucl. Fusion 40, 557 (2000)10.1088/0029-5515/40/3Y/316]. The measurements are based on three techniques: (1) measurement of the toroidal field created by the poloidal halo current, either with segmented Rogowski coils or discrete toroidal field sensors, (2) the direct measurement of halo currents into specially instrument tiles, and (3) small Rogowski coils placed on the mechanical supports of in-vessel components. For the segmented Rogowski coils and discrete toroidal field detectors, it is shown that the toroidal peaking factor inferred from the data is significantly less than the peaking factor of the underlying halo current distribution, and a simple model is developed to relate the two. For the array of discrete toroidal field detectors and small Rogowski sensors, the compensation steps that are used to isolate the halo current signal are described. The electrical and mechanical design of compact under-tile resistive shunts and mini-Rogowski coils is described. Example data from the various systems are shown.
Show PACS
52.70.Ds Electric and magnetic measurements
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.55.Fa Tokamaks, spherical tokamaks
52.25.Fi Transport properties

Development of a compact permanent magnet helicon plasma source for ion beam bioengineering

P. Kerdtongmee, D. Srinoum, and M. Nisoa

Rev. Sci. Instrum. 82, 103503 (2011); http://dx.doi.org/10.1063/1.3646467 (5 pages)

Online Publication Date: 11 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A compact helicon plasma source was developed as a millimeter-sized ion source for ion beam bioengineering. By employing a stacked arrangement of annular-shaped permanent magnets, a uniform axial magnetic flux density up to 2.8 kG was obtained. A cost effective 118 MHz RF generator was built for adjusting forward output power from 0 to 40 W. The load impedance and matching network were then analyzed. A single loop antenna and circuit matching elements were placed on a compact printed circuit board for 50 Ω impedance matching. A plasma density up to 1.1 × 1012 cm−3 in the 10 mm diameter tube under the magnetic flux density was achieved with 35 W applied RF power.
Show PACS
87.80.-y Biophysical techniques (research methods)
52.50.Dg Plasma sources
52.40.Fd Plasma interactions with antennas; plasma-filled waveguides

Deconvolution of Stark broadened spectra for multi-point density measurements in a flow Z-pinch

G. V. Vogman and U. Shumlak

Rev. Sci. Instrum. 82, 103504 (2011); http://dx.doi.org/10.1063/1.3647975 (7 pages)

Online Publication Date: 13 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Stark broadened emission spectra, once separated from other broadening effects, provide a convenient non-perturbing means of making plasma density measurements. A deconvolution technique has been developed to measure plasma densities in the ZaP flow Z-pinch experiment. The ZaP experiment uses sheared flow to mitigate MHD instabilities. The pinches exhibit Stark broadened emission spectra, which are captured at 20 locations using a multi-chord spectroscopic system. Spectra that are time- and chord-integrated are well approximated by a Voigt function. The proposed method simultaneously resolves plasma electron density and ion temperature by deconvolving the spectral Voigt profile into constituent functions: a Gaussian function associated with instrument effects and Doppler broadening by temperature; and a Lorentzian function associated with Stark broadening by electron density. The method uses analytic Fourier transforms of the constituent functions to fit the Voigt profile in the Fourier domain. The method is discussed and compared to a basic least-squares fit. The Fourier transform fitting routine requires fewer fitting parameters and shows promise in being less susceptible to instrumental noise and to contamination from neighboring spectral lines. The method is evaluated and tested using simulated lines and is applied to experimental data for the 229.69 nm C III line from multiple chords to determine plasma density and temperature across the diameter of the pinch. These measurements are used to gain a better understanding of Z-pinch equilibria.
Show PACS
52.25.-b Plasma properties
52.58.Lq Z-pinches, plasma focus, and other pinch devices
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
52.80.Yr Discharges for spectral sources (including inductively coupled plasma)

Design and use of an Elsässer probe for analysis of Alfvén wave fields according to wave direction

D. J. Drake, C. A. Kletzing, F. Skiff, G. G. Howes, and S. Vincena

Rev. Sci. Instrum. 82, 103505 (2011); http://dx.doi.org/10.1063/1.3649950 (7 pages)

Online Publication Date: 17 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have designed an electric and magnetic field probe which simultaneously measure both quantities in the directions perpendicular to the background magnetic field for application to Alfvén wave experiments in the Large Plasma Device at UCLA. This new probe allows for the projection of measured wave fields onto generalized Elsässer variables. Experiments were conducted in a singly ionized He plasma at 1850 G in which propagation of Alfvén waves was observed using this new probe. We demonstrate that a clear separation of transmitted and reflected signals and determination of Poynting flux and Elsässer variables can be achieved.
Show PACS
52.75.-d Plasma devices
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)

Application of an impedance matching transformer to a plasma focus

B. L. Bures, C. James, M. Krishnan, and R. Adler

Rev. Sci. Instrum. 82, 103506 (2011); http://dx.doi.org/10.1063/1.3648117 (5 pages)

Online Publication Date: 18 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A plasma focus was constructed using an impedance matching transformer to improve power transfer between the pulse power and the dynamic plasma load. The system relied on two switches and twelve transformer cores to produce a 100 kA pulse in short circuit on the secondary at 27 kV on the primary with 110 J stored. With the two transformer systems in parallel, the Thevenin equivalent circuit parameters on the secondary side of the driver are: C = 10.9 μF, V0 = 4.5 kV, L = 17 nH, and R = 5 mΩ. An equivalent direct drive circuit would require a large number of switches in parallel, to achieve the same Thevenin equivalent. The benefits of this approach are replacement of consumable switches with non-consumable transformer cores, reduction of the driver inductance and resistance as viewed by the dynamic load, and reduction of the stored energy to produce a given peak current. The system is designed to operate at 100 Hz, so minimizing the stored energy results in less load on the thermal management system. When operated at 1 Hz, the neutron yield from the transformer matched plasma focus was similar to the neutron yield from a conventional (directly driven) plasma focus at the same peak current.
Show PACS
52.75.-d Plasma devices
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables

Detection efficiency vs. cathode and anode separation in cylindrical vacuum photodiodes used for measuring x-rays from plasma focus device

T. K. Borthakur, N. Talukdar, N. K. Neog, C. V. S. Rao, and A. Shyam

Rev. Sci. Instrum. 82, 103507 (2011); http://dx.doi.org/10.1063/1.3652962 (7 pages)

Online Publication Date: 25 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A qualitative study on the performance of cylindrical vacuum photodiodes (VPDs) for x-ray detection in plasma focus device has been carried out. Various parameters of VPD such as electrode's diameter, electrode's separation, and its sensitivity are experimentally tested in plasma focus environment. For the first time it is found experimentally that the electrode-separation in the lateral direction of the two coaxial electrodes of cylindrical VPD also plays an important role to increase the efficiency of the detector. The efficiency is found to be highest for the detector with smaller cathode-anode lateral gap (1.5 mm) with smaller photo cathode diameter (10 mm). A comparison between our VPD with PIN (BPX-65) diode as an x-ray detector has also been made.
Show PACS
52.70.La X-ray and γ-ray measurements
29.40.-n Radiation detectors
07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
84.47.+w Vacuum tubes
85.60.Dw Photodiodes; phototransistors; photoresistors

Time-frequency analysis for microwave reflectometry data processing in the HL-2A tokamak

W. L. Zhong, Z. B. Shi, X. L. Zou, X. T. Ding, X. L. Huang, Y. B. Dong, Z. T. Liu, W. W. Xiao, X. Q. Ji, Z. Y. Cui, Yi Liu, L. W. Yan, Q. W. Yang, and X. R. Duan

Rev. Sci. Instrum. 82, 103508 (2011); http://dx.doi.org/10.1063/1.3657157 (5 pages)

Online Publication Date: 27 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The Choi-Williams distribution (CWD) technique is introduced as a time-frequency tool for processing data measured from the new developed homodyne and the fixed frequency reflectometry in the HL-2A tokamak. The comparison between spectrogram and CWD for the simulated signal is presented. It indicates that the CWD can greatly improve the representation of the time-frequency content of the multi-components signal. Its effectiveness is demonstrated through two applications in HL-2A, which are the extraction of beat frequencies from the frequency modulated-continuous wave reflectometry (FM-CW) and the characterizing of the fluctuations. The density profile inversed from the group delay of the FM-CW and the density fluctuations deduced from the fixed-frequency reflectometry would be more reliable and accurate by using the CWD technique.
Show PACS
52.70.Gw Radio-frequency and microwave measurements
52.25.Gj Fluctuation and chaos phenomena
52.55.Fa Tokamaks, spherical tokamaks

Properties of a capillary discharge-produced argon plasma waveguide for shorter wavelength source application

Shohei Sakai, Takeshi Higashiguchi, Nadezhda Bobrova, Pavel Sasorov, Jun Miyazawa, Noboru Yugami, Yasuhiko Sentoku, and Ryosuke Kodama

Rev. Sci. Instrum. 82, 103509 (2011); http://dx.doi.org/10.1063/1.3657136 (4 pages)

Online Publication Date: 31 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the operation of a discharge-produced argon (Ar) plasma waveguide in an alumina (Al2O3) capillary to guide a 1016-W/cm2 ultrashort laser pulse for shorter wavelength light sources at high repetition rate operation. The electron density in the plasma channel was measured to be 1 × 1018 cm−3. Modeling with a one-dimensional magnetrohydrodynamic code was used to evaluate the degree of ionization of Ar in the preformed plasma channel. The observed spectrum of the laser pulse after propagation in the argon plasma waveguide was not modified and was well reproduced by a particle in cell simulation.
Show PACS
52.40.Fd Plasma interactions with antennas; plasma-filled waveguides
52.65.Kj Magnetohydrodynamic and fluid equation
52.65.Rr Particle-in-cell method
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
52.38.Dx Laser light absorption in plasmas (collisional, parametric, etc.)
back to top Microscopy and Imaging

Field programmable gate array based reconfigurable scanning probe/optical microscope

Derek B. Nowak, A. J. Lawrence, Zechariah K. Dzegede, Justin C. Hiester, Cliff Kim, and Erik J. Sánchez

Rev. Sci. Instrum. 82, 103701 (2011); http://dx.doi.org/10.1063/1.3643770 (9 pages)

Online Publication Date: 3 October 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The increasing popularity of nanometrology and nanospectroscopy has pushed researchers to develop complex new analytical systems. This paper describes the development of a platform on which to build a microscopy tool that will allow for flexibility of customization to suit research needs. The novelty of the described system lies in its versatility of capabilities. So far, one version of this microscope has allowed for successful near-field and far-field fluorescence imaging with single molecule detection sensitivity. This system is easily adapted for reflection, polarization (Kerr magneto-optical (MO)), Raman, super-resolution techniques, and other novel scanning probe imaging and spectroscopic designs. While collecting a variety of forms of optical images, the system can simultaneously monitor topographic information of a sample with an integrated tuning fork based shear force system. The instrument has the ability to image at room temperature and atmospheric pressure or under liquid. The core of the design is a field programmable gate array (FPGA) data acquisition card and a single, low cost computer to control the microscope with analog control circuitry using off-the-shelf available components. A detailed description of electronics, mechanical requirements, and software algorithms as well as examples of some different forms of the microscope developed so far are discussed.
Show PACS
07.79.Fc Near-field scanning optical microscopes
42.30.Va Image forming and processing
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
07.60.Pb Conventional optical microscopes
Page 1 of 3 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. Note: Scalable multiphoton coincidence-counting electronics
  2. Invited Review Article: IceCube: An instrument for neutrino astronomy
  3. Note: A thermally stable tension meter for atmospheric soundings using kites
  4. Inductive conductivity tensor measurement for flowline or material samples
  5. Time-resolved ellipsometry for studies of heat transfer at liquid/solid and gas/solid interfaces
Go to AIP Home
Copyright © American Institute of Physics
close