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Dec 2006

Volume 77, Issue 12, Articles (12xxxx)

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High-reflectivity Cr/Sc multilayer condenser for compact soft x-ray microscopy

H. Stollberg, S. Yulin, P. A. C. Takman, and H. M. Hertz

Rev. Sci. Instrum. 77, 123101 (2006); http://dx.doi.org/10.1063/1.2400665 (6 pages) | Cited 8 times

Online Publication Date: 6 December 2006

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The condenser is a critical component in compact water-window x-ray microscopes as it influences the exposure time via its efficiency and the resolution via its numerical aperture. Normal-incidence multilayer mirrors can reach large geometrical collection efficiencies and match the numerical aperture of the zone plate but require advanced processing for high total reflectivity. In the present article we demonstrate large-diameter normal-incidence spherical Cr/Sc multilayer condensers with high and uniform reflectivity. Dc-magnetron sputtering was used to deposit 300 bilayers of Cr/Sc with a predetermined d-spacing matching the λ = 3.374 nm operating wavelength on spherical substrates. The mirrors show a uniform reflectivity of ∼ 3% over the full 58 mm diameter condenser area. With these mirrors an improvement in exposure time by a factor of 10 was achieved, thereby improving the performance of the compact x-ray microscope significantly.
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07.85.Tt X-ray microscopes
42.79.Wc Optical coatings
42.79.Bh Lenses, prisms and mirrors

Spectral matching consideration in the design of a novel x-ray image intensifier

Chunyu Yu, Benkang Chang, and Dianxiu Wei

Rev. Sci. Instrum. 77, 123102 (2006); http://dx.doi.org/10.1063/1.2400022 (3 pages)

Online Publication Date: 13 December 2006

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In this article, a novel x-ray image intensifier is introduced. It is mainly composed of an x-ray intensifying screen and a low-light-level (L3) image intensifier. In order to obtain a bright enough image, the spectral compatibility among three different combinations of the x-ray intensifying screen and the photocathode is analyzed. The comparison indicates that a (Zn,Cd)S:Ag screen is superior to either a CaWO4 screen or a Gd2O2S:Tb screen when combined with the Super S25 photocathode and spectral compatibility analysis is a useful guide when designing an optoelectronic imaging device.
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42.79.Ls Scanners, image intensifiers, and image converters
07.85.-m X- and γ-ray instruments
42.15.Eq Optical system design
85.60.Ha Photomultipliers; phototubes and photocathodes

Simultaneous measurement of electric birefringence, light scattering, and electric current for liquid systems

M. Alessi, E. Zothner, E. Acosta, and M. Bisceglia

Rev. Sci. Instrum. 77, 123103 (2006); http://dx.doi.org/10.1063/1.2403838 (3 pages)

Online Publication Date: 21 December 2006

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In this work we present an experimental setup that allows measuring, simultaneously, the electric birefringence, the electric light scattering, and the cell electrical current under the action of an external electric field. The basic design corresponds to a standard birefringence setup. The Kerr cell was built to permit the observation of 90° light scattering. The high voltage pulse generator is used to measure the electrical current across the Kerr cell. We present experimental data, taken in colloidal systems with different electrical conductivities.
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78.20.Jq Electro-optical effects
78.20.Fm Birefringence
82.70.Dd Colloids

kHz stimulated Brillouin spectroscopy

S. Ohno, T. Sonehara, E. Tatsu, A. Koreeda, and S. Saikan

Rev. Sci. Instrum. 77, 123104 (2006); http://dx.doi.org/10.1063/1.2403936 (5 pages) | Cited 5 times

Online Publication Date: 21 December 2006

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We have developed a high precision stimulated Brillouin spectrometer. Since this spectrometer is based on the stimulated light scattering, Brillouin measurements are possible without any signal reduction even at extremely low temperatures. The use of stable lasers for the pump and probe waves and a real-time frequency-monitor gives a high frequency resolution reaching 20 kHz, which is, to the best of authors knowledge, the highest resolution so far reported for Brillouin spectrometers. The frequency-monitor has been achieved through the measurement of the beat frequency between the two lasers by using a microwave frequency counter. With this spectrometer, we have succeeded to measure Brillouin spectra in single crystals of TeO2 from room temperature to liquid helium temperature. Furthermore, in a sample with [110] surfaces, we have observed a spectral splitting due to the multireflection of phonons at crystal surfaces.
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07.60.Rd Visible and ultraviolet spectrometers
42.65.Es Stimulated Brillouin and Rayleigh scattering
78.35.+c Brillouin and Rayleigh scattering; other light scattering
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy

Synchrotron radiation x-ray beam profile monitor using chemical vapor deposition diamond film

Togo Kudo, Sunao Takahashi, Nobuteru Nariyama, Toko Hirono, Takeshi Tachibana, and Hideo Kitamura

Rev. Sci. Instrum. 77, 123105 (2006); http://dx.doi.org/10.1063/1.2403843 (4 pages)

Online Publication Date: 26 December 2006

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Photoluminescence (PL) of a Si-doped polycrystalline diamond film fabricated using the chemical vapor deposition technique was employed to measure the profile of a synchrotron radiation pink x-ray beam emitted from an in-vacuum hybrid undulator at the SPring-8 facility. The spectrum of the section of the diamond film penetrated by the emitted visible red light exhibited a peak at 739 nm and a wideband structure extending from 550 to 700 nm. The PL intensity increased with the absorbed dose of the incident beam in the diamond within a dynamic range of 103. A two-dimensional distribution of the PL intensity revealed the undulator beam profile.
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07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
78.66.-w Optical properties of specific thin films
78.55.Hx Other solid inorganic materials

Amplitude and frequency noise sensitivities of optical frequency discriminators based on Fabry–Pérot interferometers and the frequency modulation technique

Elio Bava, Gianluca Galzerano, and Cesare Svelto

Rev. Sci. Instrum. 77, 123106 (2006); http://dx.doi.org/10.1063/1.2405397 (9 pages) | Cited 2 times

Online Publication Date: 26 December 2006

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We report on the sensitivities to frequency and amplitude noise of optical frequency discriminators based on Fabry–Pérot interferometers and the frequency modulation (Pound–Drever–Hall) technique. The response to frequency and amplitude noise is obtained by analyzing the demodulated transients to phase or amplitude steps impressed on the incident frequency modulated light. The responses in the Fourier frequency domain are then obtained by performing the Laplace transform of the demodulated transients. As expected, when the laser frequency is coincident with the Fabry–Pérot resonance, this discriminator is completely immune to amplitude noise. To simulate real operations, the amplitude noise immunity is evaluated in the presence of small detunings between the laser frequency and the Fabry–Pérot resonance. Diagrams of the responses to both types of noise are reported for symmetric and asymmetric resonators. The Pound–Drever–Hall discriminator turns out to be insensitive to the asymmetry of the Fabry–Pérot resonator. The performed evaluations lead to a simple estimation of the minimum detectable frequency noise in terms of a given laser intensity noise.
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07.60.Ly Interferometers
42.79.Hp Optical processors, correlators, and modulators
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Frequency stabilization of transverse Zeeman He–Ne laser by means of model predictive control

Dejiao Lin, Gaoliang Dai, Chunyong Yin, and Xiangqian Jiang

Rev. Sci. Instrum. 77, 123301 (2006); http://dx.doi.org/10.1063/1.2400021 (5 pages) | Cited 1 time

Online Publication Date: 1 December 2006

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A model predictive control (MPC) technique is proposed for the frequency stabilization of transverse Zeeman He–Ne laser. The beat frequency locking method is applied as the criterion of frequency stabilization. When heated by the voltage output of the feedback electronic circuit, the copper wire twisted around the laser tube is applied to maintain the length of the laser cavity and stabilize the frequency of the laser. Four steps for MPC design, i.e., model setup, output prediction, selection of reference path, and calculation of control quality, have been introduced. By this means, a single-chip microprocessor (80C196) generates a pulse width modulation wave that is transferred into a heating signal. The calibration result shows that the frequency stability of our proposed transverse Zeeman laser reaches 5.5×10−11 by means of the MPC method.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.60.By Design of specific laser systems
42.60.Fc Modulation, tuning, and mode locking

Extreme ultraviolet diagnostics of preformed plasma in laser-driven proton acceleration experiments

Eugene N. Ragozin, Alexander S. Pirozhkov, Akifumi Yogo, Jinglong Ma, Koichi Ogura, Satoshi Orimo, Akito Sagisaka, Michiaki Mori, Zhong Li, Mamiko Nishiuchi, and Hiroyuki Daido

Rev. Sci. Instrum. 77, 123302 (2006); http://dx.doi.org/10.1063/1.2405391 (6 pages) | Cited 4 times

Online Publication Date: 20 December 2006

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Proton acceleration experiments involving a 5 μm thick Ti foil target irradiation are carried out with the femtosecond Ti:sapphire laser JLITE-X. The plasma emission at 13.5 nm is recorded employing concave multilayer mirrors, which image the front- and rear-side plasmas onto the sensitive surfaces of a fast x-ray photodiode and a backside-illuminated charge coupled device. Online time-of-flight fast-particle measurements are performed simultaneously with the extreme ultraviolet (XUV) measurements. A strong correlation is observed between the energetic proton signal and the spatiotemporal behavior of the XUV plasma emission. In particular, the longer duration of the prepulse-produced XUV plasma emission indicates a lowering of the maximum proton energy. This allows using the XUV emission for the diagnostics of the high-intensity laser–solid-target interaction.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.70.Nc Particle measurements
52.70.La X-ray and γ-ray measurements
52.38.Kd Laser-plasma acceleration of electrons and ions
52.40.Mj Particle beam interactions in plasmas
52.25.Os Emission, absorption, and scattering of electromagnetic radiation

Cusp type electrostatic analyzer for measurements of medium energy charged particles

S. Kasahara, K. Asamura, Y. Saito, T. Takashima, M. Hirahara, and T. Mukai

Rev. Sci. Instrum. 77, 123303 (2006); http://dx.doi.org/10.1063/1.2405358 (5 pages) | Cited 4 times

Online Publication Date: 21 December 2006

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We have developed a new electrostatic analyzer which enables medium energy (≲200 keV/q) plasma particle measurements with full solid angle coverage. The design of the test model realizes the uppermost measurement energy of ∼ 200 keV/q with applied high voltages of ±5 kV. Laboratory experiments with the test model analyzer show that its performance agrees with numerical simulations. The test model design is well suited for combination with a mass analysis unit, while our new design can also be applied to medium energy electron measurements. Medium energy ion/electron sensors with this new design will surely be appreciated for upcoming space missions that will observe hot/energetic plasma structures in the regions such as the inner magnetosphere or reconnection region.
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07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
52.70.Ds Electric and magnetic measurements
52.40.Mj Particle beam interactions in plasmas
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
52.35.Vd Magnetic reconnection
94.30.cp Magnetic reconnection
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Compact high current generator for x-ray radiography

A. V. Kharlov, B. M. Kovalchuk, and V. B. Zorin

Rev. Sci. Instrum. 77, 123501 (2006); http://dx.doi.org/10.1063/1.2400667 (5 pages) | Cited 9 times

Online Publication Date: 12 December 2006

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We report here a design of the portable high current generator, which can be used for a row of experiments and applications, including, but not limited to, X pinch, plasma focus, vacuum spark, etc. The X generator consists of the capacitor bank, multigap spark switch, load chamber, and built-in high voltage triggering generator. The capacitor bank consists of 12 General Atomics 35404 type capacitors (20 nF, 25 nH, 0.2 Ω, 100 kV). It stores ∼ 0.8 kJ at 80 kV charging voltage. Each three capacitors are commuted to a load by the multigap spark switch, which is able to commute by eight parallel channels. Switches operate in ambient air at atmospheric pressure. At 76 kV charging voltage the generator provides ∼ 260 kA with 120 ns rise time and 5 nH inductive load and ∼ 220 kA with 145 ns rise time and 10 nH. Delay of output pulse relative to high voltage triggering pulse is ∼ 65 ns with 5 ns jitter. The dimensions of the generator are 1240×1240×225 mm3 and the weight is ∼ 250 kg, and only one high voltage power supply is required as additional equipment for the generator. The generator with a pumping system is placed on area about 0.5 m2. Operation and handling are very simple, because no oil nor purified gases are required for the generator. The X generator has been successfully employed for experiments on the Ni X pinch load. X-ray pulse duration (full width at half maximum above 1 keV) was about 5 ns. Radiation yield Wr ≥ 500 mJ was observed in the 1.2–1.5 KeV range and Wr ≥ 20 mJ in the 3–5 keV energy range, which is comparable to results, obtained on the nanosecond accelerators. Clearly resolved images of 6 μm wire indicate micron level size of hot spot. These results demonstrate possibility of this generator for application for x-ray backlighting.
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52.58.Lq Z-pinches, plasma focus, and other pinch devices
52.80.Mg Arcs; sparks; lightning; atmospheric electricity
52.75.Kq Plasma switches (e.g., spark gaps)
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors

Compatible operation of the power system for steady state and pulse modes in a magnetic torus KT-5D

Yi Yu, Zhi-jiang Wang, Min Xu, Zhen-hua Zhu, Rong-hua Lu, Yi-zhi Wen, Chang-xuan Yu, Shu-de Wan, Wan-dong Liu, Jun Wang, Xiao-yuan Xu, and Ling-ying Hu

Rev. Sci. Instrum. 77, 123502 (2006); http://dx.doi.org/10.1063/1.2403091 (3 pages) | Cited 4 times

Online Publication Date: 15 December 2006

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Compatible operation of steady state mode and pulse mode is realized in the KT-5D device. New power supplies with the operation control systems for the steady state toroidal magnetic field as well as for the vertical field are added, and the rf wave injection systems for sustaining steady state plasmas are upgraded. After the modification, the device now can work not only as a tokomak with pulsed plasma currents as it was but also as a simple magnetized torus with steady state plasma discharges. It allows more flexible and efficient experimental researches on the magnetically confined plasmas to be carried on in the same device.
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52.55.Fa Tokamaks, spherical tokamaks
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma
52.25.Fi Transport properties
52.25.Xz Magnetized plasmas

Development of a pulsed-biasing system and temperature measurement techniques for transient heating experiments on plasma-material interactions

J. Hanna, R. Doerner, R. Hernandez, R. Seraydarian, and R. Pugno

Rev. Sci. Instrum. 77, 123503 (2006); http://dx.doi.org/10.1063/1.2403938 (5 pages) | Cited 4 times

Online Publication Date: 21 December 2006

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A power switching system has been developed to reverse the voltage polarity on the sample holder of PISCES-B from negative to positive potential in the microsecond time scale. Positive biasing draws electrons from the steady-state plasma through the sample, creating Ohmic heating on the surface. This pulsed biasing is used to replicate the transient heat loads that will be seen on plasma facing components during transient events, such as edge localized modes, in a device such as ITER. Surface temperatures are measured using two pyrometry techniques, a fast two-color system and a slower, more sensitive spectral system.
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52.50.Nr Plasma heating by DC fields; ohmic heating, arcs
52.40.Hf Plasma-material interactions; boundary layer effects
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
52.70.Gw Radio-frequency and microwave measurements
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables

Far-infrared polarimetric characterization of metallic mirrors exposed to a tokamak plasma

L. Giudicotti, M. Brombin, S. L. Prunty, L. De Pasqual, and E. Zilli

Rev. Sci. Instrum. 77, 123504 (2006); http://dx.doi.org/10.1063/1.2400216 (7 pages) | Cited 1 time

Online Publication Date: 29 December 2006

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We describe the polarimetric characterization in the far infrared (λ = 118.8 μm) of a set of metallic mirrors and of a corner cube retroreflector whose surface has been exposed to a tokamak plasma. The objective of the measurements was to investigate possible changes of the polarization state of the incident radiation due to plasma depositions and identify possible sources of errors for the measurement of the ITER q profile by far-infrared (FIR) polarimetry. Tests have been made on Mo and Cu mirrors exposed to the plasma in TEXTOR and Tore Supra. A corner cube retroreflector exposed in Tore Supra was also tested. The thickness and composition of the plasma depositions on these optical elements were known by previous surface analysis and visible ellipsometry studies. Our tests have been carried out in the FIR laboratory of the RFX experiment in Padova, Italy, and in the Laser Research Laboratory of the Department of Electrical and Electronic Engineering at University College Cork, Ireland, using a Stokes polarimeter assembled from components of the RFX FIR polarimetric diagnostic. The tests indicate that the plasma depositions on these elements do not affect the polarimetric response of the surface in the FIR, the only noticeable effect being a significant decrease of the reflectivity in a highly damaged region of limited area on the surface of one mirror. No other effect that may prevent the use of mirrors or corner-cube retroreflectors with this kind of surface damage in the poloidal ITER polarimeter has been observed.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
07.60.Fs Polarimeters and ellipsometers
52.55.Fa Tokamaks, spherical tokamaks
52.40.Hf Plasma-material interactions; boundary layer effects
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
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Room-temperature tunnel current amplifier and experimental setup for high resolution electronic spectroscopy in millikelvin scanning tunneling microscope experiments

Hélène le Sueur and Philippe Joyez

Rev. Sci. Instrum. 77, 123701 (2006); http://dx.doi.org/10.1063/1.2400024 (5 pages) | Cited 3 times

Online Publication Date: 1 December 2006

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The spectroscopic resolution of tunneling measurements performed with a scanning tunneling microscope is ultimately limited by the temperature at which the experiment is performed. To take advantage of the potential high spectroscopic resolution associated with operating a scanning tunneling microscope in a dilution refrigerator we have designed a room-temperature tunnel current amplifier having very small back action on the tunnel contact and allowing to nearly reach the predicted energy resolution. This design is a modification of the standard operational amplifier based tip-biasing current-voltage converter which implements differential voltage sensing and whose back action on the tip voltage is only ∼ 2 μV rms for a 14 MV/A transimpedance and 22 kHz bandwidth.
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07.79.Cz Scanning tunneling microscopes
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment

Setup of a fluorescence lifetime and spectral correlated acquisition system for two-photon microscopy

Corentin Spriet, Dave Trinel, Sophie Laffray, Marc Landry, Bernard Vandenbunder, Laurent Heliot, and Jacques Barbillat

Rev. Sci. Instrum. 77, 123702 (2006); http://dx.doi.org/10.1063/1.2400015 (6 pages)

Online Publication Date: 6 December 2006

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In this article we present a complete laser scanning microscope designed for simultaneous spectral and lifetime measurements from every point of the specimen located within the field of view. The pulsed laser source used for two-photon excitation provides good spatial resolution with minimal invasivity. In addition, the detection module was optimized for minimal photon loss, allowing laser power minimization and further reduction of cells photodamage. Analysis of biological samples illustrates the performances of this configuration, particularly when applied to fluorescent resonance energy transfer (FRET) measurements. Indeed, multiparametric acquisition is particularly useful to discriminate between FRET and artifactual response due to acquisition invasivity or cell heterogeneity. Combined with adapted homemade driving software, this system is stable, portable, and optimized for living cell studies.
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07.60.Pb Conventional optical microscopes
87.64.M- Optical microscopy
42.15.Eq Optical system design
87.80.-y Biophysical techniques (research methods)
87.64.K- Spectroscopy

Phase modulation atomic force microscope with true atomic resolution

Takeshi Fukuma, Jason I. Kilpatrick, and Suzanne P. Jarvis

Rev. Sci. Instrum. 77, 123703 (2006); http://dx.doi.org/10.1063/1.2405361 (5 pages) | Cited 15 times

Online Publication Date: 21 December 2006

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We have developed a dynamic force microscope (DFM) working in a novel operation mode which is referred to as phase modulation atomic force microscopy (PM-AFM). PM-AFM utilizes a fixed-frequency excitation signal to drive a cantilever, which ensures stable imaging even with occasional tip crash and adhesion to the surface. The tip-sample interaction force is detected as a change of the phase difference between the cantilever deflection and excitation signals and hence the time response is not influenced by the Q factor of the cantilever. These features make PM-AFM more suitable for high-speed imaging than existing DFM techniques such as amplitude modulation and frequency modulation atomic force microscopies. Here we present the basic principle of PM-AFM and the theoretical limit of its performance. The design of the developed PM-AFM is described and its theoretically limited noise performance is demonstrated. Finally, we demonstrate the true atomic resolution imaging capability of the developed PM-AFM by imaging atomic-scale features of mica in water.
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07.79.Lh Atomic force microscopes
68.35.Np Adhesion

Novel probe for the in situ measurement of particle size distributions

Michael K. Francis, Richard V. Calabrese, and Supathorn Phongikaroon

Rev. Sci. Instrum. 77, 123704 (2006); http://dx.doi.org/10.1063/1.2405388 (8 pages)

Online Publication Date: 29 December 2006

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The development of a novel instrument for the in situ measurement of particle size distributions in the size range of 3–200 μm is presented. The system uses high magnification optics, housed in a stainless steel probe, which can be inserted into a process stream or vessel, where images of the dispersed phase particles are recorded. A pulsed light source is used to freeze the motion of the particles in the field of view and present an image of the dispersion onto a charge-coupled device camera chip. The images are digitized and stored for later processing. Automated image analysis routines have been developed for extracting particle size information from the acquired images. An extensive validation of the instrument has been performed for spherical particles, which has produced several important findings. First, a size bias in the depth of field (DOF) exists which favors larger particles. An experiment procedure was developed for the direct measurement of DOF size biases. Additionally, the behavior of the instrument is dependent on the environmental conditions, such as dispersed phase concentration and the difference in index of refraction between continuous phase and dispersed phase.
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06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
42.30.Va Image forming and processing
42.79.Pw Imaging detectors and sensors
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Versatile cluster based photoelectron spectrometer

K. L. Knappenberger, C. E. Jones, M. A. Sobhy, and A. W. Castleman

Rev. Sci. Instrum. 77, 123901 (2006); http://dx.doi.org/10.1063/1.2393163 (8 pages) | Cited 6 times

Online Publication Date: 1 December 2006

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A recently constructed cluster based photoelectron spectrometer is described. This instrumentation is unique in that it enables the kinetic energy analysis of electrons ejected from both anions and neutral clusters. This capability permits the investigation of discrete electronic levels in all charge states (anionic, neutral, and cationic). A laser vaporization plasma reactor cluster source affixed with a sublimation cell is employed to produce a variety of metal clusters, and the resulting cluster distributions are analyzed with time-of-flight mass spectrometry. The corresponding electronic structure is analyzed with a “magnetic bottle” photoelectron spectrometer. Examples of instrument performance operating in both anion photodetachment and neutral multiphoton ionization (MPI) modes are provided. In the case of neutral MPI, the corresponding product distribution is collected with a Wiley-McLaren [Rev. Sci. Instrum. 26, 1150 (1955) ] mass spectrometer mounted perpendicular to the magnetic bottle photoelectron spectrometer.
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07.81.+a Electron and ion spectrometers

New diamond anvil cell system for in situ resistance measurement under extreme conditions

Ming Li, Chunxiao Gao, Yanzhang Ma, Yanchun Li, Xiaodong Li, Hui Li, Jing Liu, Aimin Hao, Chunyuan He, Xiaowei Huang, Dongmei Zhang, and Cuiling Yu

Rev. Sci. Instrum. 77, 123902 (2006); http://dx.doi.org/10.1063/1.2400669 (4 pages) | Cited 4 times

Online Publication Date: 6 December 2006

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We report an alumina-encapsulated microcircuit on a diamond anvil for high-pressure and high-temperature electrical conductivity measurement. An alumina thin film was deposited on a diamond anvil as a thermal insulation layer for laser heating, on which a molybdenum film was deposited and photolithographically fabricated to a van der Pauw circuit. The introduction of the alumina layer significantly improves the laser heating performance. This specially fabricated diamond anvil permits us to measure the resistivity of (Mg0.875Fe0.125)2SiO4 at 3450 K and 35 GPa in a laser-heated diamond anvil cell. We expect to substantially extend the pressure-temperature scale of in situ resistivity measurement.
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84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
07.20.Ka High-temperature instrumentation; pyrometers
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology

Speed of sound instrument for fluids with pressures up to 100 MPa

Karsten Meier and Stephan Kabelac

Rev. Sci. Instrum. 77, 123903 (2006); http://dx.doi.org/10.1063/1.2400019 (8 pages) | Cited 3 times

Online Publication Date: 12 December 2006

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An instrument for highly accurate measurements of the speed of sound in fluids in the temperature range between 240 and 420 K with pressures up to 100 MPa is described. The measurement principle of the speed of sound sensor is based on a double path length pulse-echo technique. The achieved measurement uncertainties are 3 mK for the temperature, 0.01% for the pressure below 10 MPa and 0.005% for the pressure between 10 and 100 MPa, and 0.014% for the speed of sound. The high accuracy of the instrument is demonstrated by measurements in liquid water and compressed argon. The results for argon prove that our pulse-echo technique agrees with the highly accurate spherical resonator technique, which is commonly employed for speed of sound measurements in gases, in the pressure range where both methods overlap within our measurement uncertainty.
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An oscillating coil system for contactless electrical conductivity measurements of aerodynamically levitated melts

Lawrie Skinner and Adrian C. Barnes

Rev. Sci. Instrum. 77, 123904 (2006); http://dx.doi.org/10.1063/1.2403939 (4 pages) | Cited 1 time

Online Publication Date: 15 December 2006

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A new method for the contactless measurement of the electrical conductivity σ of high temperature aerodynamically levitated materials is presented. The apparatus, based on an oscillating coil system, improves considerably on previously reported static coil techniques by eliminating the large errors introduced by temperature drifts in the measurement system. With this system we demonstrate that accurate and fast measurements can be made for liquid metals and semiconductors with conductivities in the range 104−107 Ω−1 m−1. Measurements of σ of liquid Ge as a function of temperature have been made to demonstrate the reliability of the method and give σ = 1.52±0.03×106 Ω−1 m−1 at 1250 K in good agreement with previous measurements. The speed and precision of the apparatus will allow new studies of the electrical properties of high temperature liquids and glasses including precise observations of melting and glass transitions under quenching conditions.
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84.32.Hh Inductors and coils; wiring
06.30.Ka Basic electromagnetic quantities
72.15.Cz Electrical and thermal conduction in amorphous and liquid metals and alloys
72.80.Cw Elemental semiconductors

Forward modeling method for microstructure reconstruction using x-ray diffraction microscopy: Single-crystal verification

R. M. Suter, D. Hennessy, C. Xiao, and U. Lienert

Rev. Sci. Instrum. 77, 123905 (2006); http://dx.doi.org/10.1063/1.2400017 (12 pages) | Cited 12 times

Online Publication Date: 20 December 2006

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We describe and illustrate a forward modeling method for quantitatively reconstructing the geometry and orientation of microstructural features inside of bulk samples from high-energy x-ray diffraction microscopy data. Data sets comprise charge-coupled device images of Bragg diffracted beams originating from individual grains in a thin planar section of sample. Our analysis approach first reduces the raw images to a binary data set in which peaks have been thresholded at a fraction of their height after noise reduction processing. We then use a computer simulation of the measurement and the sample microstructure to generate calculated diffraction patterns over the same range of sample orientations used in the experiment. The crystallographic orientation at each of an array of area elements in the sample space is adjusted to optimize overlap between experimental and simulated scattering. In the present verification exercise, data are collected at the Advanced Photon Source beamline 1-ID using microfocused 50 keV x rays. Our sample is a thin silicon wafer. By choosing the appropriate threshold fraction and convergence criteria, we are able to reconstruct to ≤ 10 μm errors the subregion of the silicon wafer that remains in the incident beam throughout the rotation range of the measurement. The standard deviation of area element orientations is ≈ 0.3°. Our forward modeling approach offers a degree of noise immunity, is applicable to polycrystals and composite materials, and can be extended to include scattering rules appropriate for defected materials.
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68.55.-a Thin film structure and morphology
68.37.Yz X-ray microscopy

Pendulum viscometer: A new method for measurement of Miȩsowicz nematic shear viscosity coefficients η1 and η2

Joanna Janik, Agnieszka Krol-Otwinowska, Dagmara Sokolowska, and Jozef K. Moscicki

Rev. Sci. Instrum. 77, 123906 (2006); http://dx.doi.org/10.1063/1.2387879 (7 pages) | Cited 2 times

Online Publication Date: 28 December 2006

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We describe a new viscometer developed for liquid crystals. It has been designed for measurement of the Mięsowicz viscosity coefficient η2 (math‖v) in particular, but can be used for measuring η1 (math‖∇v) as well. The measurement is based on observation of the damped motion of a pendulum and derivation of the viscosity coefficient from the damping constant.
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47.80.-v Instrumentation and measurement methods in fluid dynamics
47.57.Lj Flows of liquid crystals
61.30.-v Liquid crystals
66.20.-d Viscosity of liquids; diffusive momentum transport
83.85.Jn Viscosity measurements

Versatile and compact capacitive dilatometer

G. M. Schmiedeshoff, A. W. Lounsbury, D. J. Luna, S. J. Tracy, A. J. Schramm, S. W. Tozer, V. F. Correa, S. T. Hannahs, T. P. Murphy, E. C. Palm, A. H. Lacerda, S. L. Bud’ko, P. C. Canfield, J. L. Smith, J. C. Lashley, et al.

Rev. Sci. Instrum. 77, 123907 (2006); http://dx.doi.org/10.1063/1.2403088 (8 pages) | Cited 26 times

Online Publication Date: 28 December 2006

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We describe the design, construction, calibration, and operation of a relatively simple differential capacitive dilatometer suitable for measurements of thermal expansion and magnetostriction from 300 to below 1 K with a low-temperature resolution of about 0.05 Å. The design is characterized by an open architecture permitting measurements on small samples with a variety of shapes. Dilatometers of this design have operated successfully with a commercial physical property measurement system, with several types of cryogenic refrigeration systems, in vacuum, in helium exchange gas, and while immersed in liquid helium (magnetostriction only) to temperatures of 30 mK and in magnetic fields to 45 T.
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07.10.-h Mechanical instruments and equipment
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
06.20.fb Standards and calibration
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In situ small angle x-ray scattering, wide angle x-ray scattering, and Raman spectroscopy of microwave synthesis

G. A. Tompsett, B. Panzarella, W. C. Conner, K. S. Yngvesson, F. Lu, S. L. Suib, K. W. Jones, and S. Bennett

Rev. Sci. Instrum. 77, 124101 (2006); http://dx.doi.org/10.1063/1.2390630 (10 pages) | Cited 3 times

Online Publication Date: 13 December 2006

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Recent studies in microwave chemistry have proven many enhancements in reaction rates and selectivities. Most dramatic are several zeolite syntheses where over an order of magnitude more rapid rates are often, but not always, found. The reasons for these enhancements are not understood in part because in situ spectroscopies under microwave exposure are problematic. Thus, techniques have been slow to develop. This study describes a novel system with which x-ray scattering and Raman studies can be performed in situ during exposure to microwave radiation. The mechanisms and rates for the syntheses of zeolites or other microwave syntheses can be studied dynamically in this manner. A 2.45 GHz waveguide system operating in single pass or as a tuned cavity was developed through which an x-ray beam and/or a Raman laser could probe a synthesis solution and the appropriate scattering are studied. The X10A beamline at Brookhaven National Synchrotron Light Source was used for these studies.
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07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
78.70.Ck X-ray scattering
81.20.-n Methods of materials synthesis and materials processing
82.33.Jx Reactions in zeolites
82.40.-g Chemical kinetics and reactions: special regimes and techniques
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