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Sep 2004

Volume 75, Issue 9, pp. 2787-3079

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back to top CONDENSED MATTER; MATERIALS

Bottom electrode crystallization method for heat treatments on thin films

E. Joanni, A. I. Mardare, C. C. Mardare, and M. B. Marques

Rev. Sci. Instrum. 75, 2950 (2004); http://dx.doi.org/10.1063/1.1783595 (5 pages) | Cited 1 time

Online Publication Date: 14 September 2004

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A simple method for crystallizing amorphous thin films was developed using platinum bottom electrodes as heating elements. A current was applied to tungsten wires in contact with the platinum and the temperature was measured using a type-K thermocouple. A proportional feedback algorithm was used for controlling the process. The performance of different platinum electrodes was studied. Pt films with different thicknesses were alternatively deposited over Ti and Zr at 700°C. Applying currents up to 2 A to the Pt films, the resistance dependence of temperature was studied. The maximum temperature, 675°C, was obtained when using 200 nm Pt films deposited at 700°C over Ti, with a power consumption of 16 W. The method was applied to the crystallization of PbZr0.52Ti0.48O3 thin films using Pt films deposited at 500°C over Ti and at 700°C over Zr. The results obtained for heat treatments at 650°C with 10°C/s heating and cooling rates showed a pure perovskite phase; the ferroelectric properties were comparable with those from films crystallized by rapid thermal annealing.
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77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
64.70.K- Solid-solid transitions
81.40.Gh Other heat and thermomechanical treatments
81.15.Fg Pulsed laser ablation deposition
77.80.Dj Domain structure; hysteresis
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology

Millisecond time resolution neutron reflection from a nematic liquid crystal

R. M. Dalgliesh, Y. G. J. Lau, R. M. Richardson, and D. J. Riley

Rev. Sci. Instrum. 75, 2955 (2004); http://dx.doi.org/10.1063/1.1783596 (5 pages)

Online Publication Date: 14 September 2004

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The director reorientation of the liquid crystal 4,4’ octyl cyanobiphenyl in the nematic phase under application of bursts of ac field have been observed using time-resolved neutron scattering in reflection geometry. The relaxation of the director has been shown to agree with existing theory, as determined by material and cell parameters. This result shows that it is possible to use neutron reflection measurements from buried interfaces to follow kinetic processes on a time scale comparable with the pulse length of the ISIS neutron source (20 ms).
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61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
61.05.fj Neutron reflectometry
back to top MICROSCOPY AND IMAGING

Optical tweezers and confocal microscopy for simultaneous three-dimensional manipulation and imaging in concentrated colloidal dispersions

Dirk L. J. Vossen, Astrid van der Horst, Marileen Dogterom, and Alfons van Blaaderen

Rev. Sci. Instrum. 75, 2960 (2004); http://dx.doi.org/10.1063/1.1784559 (11 pages) | Cited 46 times

Online Publication Date: 14 September 2004

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A setup is described for simultaneous three-dimensional manipulation and imaging inside a concentrated colloidal dispersion using (time-shared) optical tweezers and confocal microscopy. The use of two microscope objectives, one above and one below the sample, enables imaging to be completely decoupled from trapping. The instrument can be used in different trapping (inverted, upright, and counterpropagating) and imaging modes. Optical tweezers arrays, dynamically changeable and capable of trapping several hundreds of micrometer-sized particles, were created using acousto-optic deflectors. Several schemes are demonstrated to trap three-dimensional colloidal structures with optical tweezers. One combined a Pockels cell and polarizing beam splitters to create two trapping planes at different depths in the sample, in which the optical traps could be manipulated independently. Optical tweezers were used to manipulate collections of particles inside concentrated colloidal dispersions, allowing control over colloidal crystallization and melting. Furthermore, we show that selective trapping and manipulation of individual tracer particles inside a concentrated dispersion of host particles is possible as well. The tracer particles had a core–shell geometry with a high refractive index material core and a lower index material shell. The host particles consisted of the same material as the lower index shells and were fluorescently labeled. The tracer particles could be manipulated without exerting forces on the host particles because the mixture was dispersed in a solvent with the same refractive index as that of the host particles. Using counterpropagating tweezers strongly scattering particles that could not be trapped by conventional single-beam optical tweezers were trapped and manipulated.
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82.70.Dd Colloids
37.10.Vz Mechanical effects of light on atoms, molecules, and ions
07.60.Pb Conventional optical microscopes
78.20.hb Piezo-optical, elasto-optical, acousto-optical, and photoelastic effects
78.20.Jq Electro-optical effects
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.55.-m Photoluminescence, properties and materials
42.79.Fm Reflectors, beam splitters, and deflectors

Variable-temperature scanning optical and force microscope

P. S. Fodor, H. Zhu, N. G. Patil, and J. Jevy

Rev. Sci. Instrum. 75, 2971 (2004); http://dx.doi.org/10.1063/1.1784560 (5 pages) | Cited 5 times

Online Publication Date: 14 September 2004

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The implementation of a scanning microscope capable of working in confocal, atomic force and apertureless near field configurations is presented. The microscope is designed to operate in the temperature range 4–300 K, using conventional helium flow cryostats. In atomic force microscope (AFM) mode, the distance between the sample and an etched tungsten tip is controlled by a self-sensing piezoelectric tuning fork. The vertical position of both the AFM head and microscope objective can be accurately controlled using piezoelectric coarse approach motors. The scanning is performed using a compact XYZ stage, while the AFM and optical head are kept fixed, allowing scanning probe and optical measurements to be acquired simultaneously and in concert. The free optical axis of the microscope enables both reflection and transmission experiments to be performed.
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07.79.Fc Near-field scanning optical microscopes
68.37.Ps Atomic force microscopy (AFM)
07.79.Lh Atomic force microscopes
68.37.Uv Near-field scanning microscopy and spectroscopy
back to top ELECTRONICS; ELECTROMAGNETIC TECHNOLOGY; MICROWAVES

Projection ablation lithography cathode for high-current, relativistic magnetron

M. C. Jones, V. B. Neculaes, R. M. Gilgenbach, W. M. White, M. R. Lopez, Y. Y. Lau, T. A. Spencer, and D. Price

Rev. Sci. Instrum. 75, 2976 (2004); http://dx.doi.org/10.1063/1.1784561 (5 pages) | Cited 18 times

Online Publication Date: 14 September 2004

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Initial results are presented of an innovative cathode operating in a relativistic magnetron powered by an accelerator with parameters: −0.3 MV, 1–10 kA, and 0.5 μs pulse length. This cathode is fabricated by ablating a pattern on the cathode using a KrF laser. This projection ablation lithography (PAL) cathode has demonstrated fast current turn-on and microwave startup times have decreased from an average of 193 to 118 ns. The pulselength of 1 GHz microwave oscillation has increased from a 144 ns average to 217 ns. With these improvements in microwave startup and pulse length, the microwave power has approximately remained the same compared to the previously used cloth cathodes. A new triple-azimuthal emission region is tested as means of prebunching the electrons (“cathode priming”) into the three spokes desired for pi mode operation in a six-cavity magnetron. The Tri-PAL cathode priming results in the fastest startup and highest efficiency of relativistic magnetron microwave generation.
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84.40.Fe Microwave tubes (e.g., klystrons, magnetrons, traveling-wave, backward-wave tubes, etc.)
back to top NUCLEAR PHYSICS, FUSION AND PLASMAS

Hα detector system for the Helically Symmetric Experiment

S. P. Gerhardt, J. M. Canik, D. T. Anderson, and L. Owen

Rev. Sci. Instrum. 75, 2981 (2004); http://dx.doi.org/10.1063/1.1784562 (4 pages) | Cited 1 time

Online Publication Date: 14 September 2004

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A system of absolutely calibrated Hα detectors for neutral hydrogen monitoring has been designed and implemented for the Helically Symmetric eXperiment. An array of detectors at fixed poloidal angle but many toroidal angles yields a measurement of the toroidal asymmetry in Hα emission and is used for monitoring hydrogen recycling. A multichord array at the toroidal angle of the gas puff allows an accurate determination of neutral gas penetration. Preliminary neutral gas modeling allows for the estimation of the density of atomic and molecular hydrogen from the Hα emission, which are used for particle transport and flow damping studies.
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52.55.Jd Magnetic mirrors, gas dynamic traps
52.30.-q Plasma dynamics and flow
52.25.Fi Transport properties
52.55.Pi Fusion products effects (e.g., alpha-particles, etc.), fast particle effects
52.70.Nc Particle measurements
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
82.80.-d Chemical analysis and related physical methods of analysis
back to top THERMOMETRY; THERMAL DIFFUSIVITY; ACOUSTIC; PHOTOTHERMAL AND PHOTOACOUSTIC

Errors in thermochromic liquid crystal thermometry

Roland Wiberg and Noam Lior

Rev. Sci. Instrum. 75, 2985 (2004); http://dx.doi.org/10.1063/1.1777406 (10 pages) | Cited 11 times

Online Publication Date: 14 September 2004

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This article experimentally investigates and assesses the errors that may be incurred in the hue-based thermochromic liquid crystal thermochromic liquid crystal (TLC) method, and their causes. The errors include response time, hysteresis, aging, surrounding illumination disturbance, direct illumination and viewing angle, amount of light into the camera, TLC thickness, digital resolution of the image conversion system, and measurement noise. Some of the main conclusions are that: (1) The 3×8 bits digital representation of the red green and blue TLC color values produces a temperature measurement error of typically 1% of the TLC effective temperature range, (2) an eight-fold variation of the light intensity into the camera produced variations, which were not discernable from the digital resolution error, (3) this temperature depends on the TLC film thickness, and (4) thicker films are less susceptible to aging and thickness nonuniformities.
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07.20.Dt Thermometers
42.70.Df Liquid crystals
42.79.Kr Display devices, liquid-crystal devices
06.20.Dk Measurement and error theory
back to top NUCLEAR PHYSICS, FUSION AND PLASMAS

Observation of magnetohydrodynamic instability and direct measurement of local perturbed magnetic field using motional Stark effect diagnostic

R. J. Jayakumar, M. A. Makowski, S. L. Allen, M. E. Austin, A. M. Garofalo, R. J. LaHaye, H. Reimerdes, and T. L. Rhodes

Rev. Sci. Instrum. 75, 2995 (2004); http://dx.doi.org/10.1063/1.1785847 (7 pages) | Cited 6 times

Online Publication Date: 14 September 2004

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The local oscillating component of the poloidal magnetic field in plasma associated with magnetohydrodynamic (MHD) instabilities has been measured using the motional Stark effects (MSE) diagnostic on the DIII–D tokamark. The magnetic field perturbations associated with a resistive wall mode rotated by internal coils at 20 Hz was measured using the conventional MSE operation mode. These first observations of perturbations due to a MHD mode were obtained on multiple MSE channels covering a significant portion of the plasma and the radial profile of the amplitude of the perturbed field oscillations was obtained. The measured profile is similar to the profile of the amplitude of the electron temperature oscillation measured by electron cyclotron emission (ECE) measurements. In a new mode of measurement, the amplitude of a tearing mode rotating at a high frequency ( ∼ 7 kHz) was observed using the spectral analysis of high frequency MSE data on one channel. The spectrum consists of the harmonics of the light modulation employed in the MSE diagnostics, their mutual beat frequencies and their beat frequencies with the rotation frequency of the tearing mode. The value and time variation of the frequency of the observed perturbations is in good agreement with that measured by Mirnov probes and ECE. The article demonstrates that the MSE diagnostic can be used for observing low and high frequency phenomena such as MHD instabilities and electromagnetic turbulence.
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52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
52.55.Tn Ideal and resistive MHD modes; kinetic modes
52.65.Kj Magnetohydrodynamic and fluid equation
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.70.Ds Electric and magnetic measurements
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.55.Fa Tokamaks, spherical tokamaks
52.50.Qt Plasma heating by radio-frequency fields; ICR, ICP, helicons

Feasibility of a motional Stark effect system on the TCV tokamak

M. R. Siegrist, N. Hawkes, and H. Weisen

Rev. Sci. Instrum. 75, 3002 (2004); http://dx.doi.org/10.1063/1.1785848 (8 pages)

Online Publication Date: 14 September 2004

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This article presents a feasibility study for a motional Stark effect diagnostic on the TCV tokamak. A numerical simulation code has been used to identify the optimal port arrangement and geometrical layout. It predicts the expected measurement accuracy for a range of typical plasma scenarios. With the existing neutral particle injector and a detection system based on current day technology, it should be possible to determine the safety factor with an accuracy of the order of 5%. A vertically injected beam through the plasma center would allow to measure plasmas which are centered above the midplane, a common occurrence in connection with electron cyclotron resonance heating and electron cyclotron current drive experiments. In this case a new and ideally more powerful neutral beam injector would be required.
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52.55.Fa Tokamaks, spherical tokamaks
52.70.Nc Particle measurements
52.65.-y Plasma simulation
52.50.Gj Plasma heating by particle beams
back to top MICROSCOPY AND IMAGING

Mechanical effect of gold nanoparticles labeling used for biochemical sensor applications: A multimode analysis by means of SiNx micromechanical cantilever and bridge mass detectors

D. Saya, L. Nicu, M. Guirardel, Y. Tauran, and C. Bergaud

Rev. Sci. Instrum. 75, 3010 (2004); http://dx.doi.org/10.1063/1.1785849 (6 pages) | Cited 7 times

Online Publication Date: 14 September 2004

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The effect on mechanical properties of monolithic SiNx micromechanical cantilever and bridge by the adsorption of gold colloids is reported by measuring their resonance frequency shifts. It is experimentally demonstrated that higher resonance modes are more sensitive to the added mass than the fundamental resonance mode leading to increased sensitivity. This is even more significant with monolithic SiNx bridge resonators due to the tensile stress within the SiNx layer. Indeed, resonance frequencies are about ten times higher than calculation without taking into account the tensile stress which was estimated at 500 MPa. Another important result is that the adsorbed colloids do not produce significant change in the stiffness of the SiNx micromechanical resonators. Hence, it is pointed out that only the added mass of Au colloid contributes to the change in the mechanical characteristics of the resonators. Sensitivities up to 20 Hz/pg can be obtained with a minimum detectable density of gold colloids about 2.6×10−2 nanoparticles/μm2.
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85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
61.46.-w Structure of nanoscale materials
62.25.-g Mechanical properties of nanoscale systems
68.43.Mn Adsorption kinetics
82.70.Dd Colloids
07.10.Cm Micromechanical devices and systems
68.60.Bs Mechanical and acoustical properties
62.20.D- Elasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations
87.15.R- Reactions and kinetics
87.80.-y Biophysical techniques (research methods)
back to top GENERAL INSTRUMENTS

Evaluation of resolution of flexure parallel mechanisms for ultraprecision manipulation

Huy-Hoang Pham and I-Ming Chen

Rev. Sci. Instrum. 75, 3016 (2004); http://dx.doi.org/10.1063/1.1786351 (9 pages) | Cited 4 times

Online Publication Date: 14 September 2004

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A method for evaluating the resolution of ultraprecision manipulation systems based on the flexure parallel mechanism (FPM) is presented. The resolution of the open-loop system is theoretically determined by the resolution transmission from the actuated joints to the end–effector and the resolution of actuators. The method studies the definition of the resolution indicators that includes the global resolution transmission scale and the uniformity of resolution over the entire workspace of the flexure mechanism. The computational algorithm for the defined resolution indicators is established based on the sampling method. For illustration, the evaluation method is employed to gauge the resolution performance of a two-degree-of-freedom and a three-degree-of-freedom (3-DOF) planar FPM. To demonstrate its application for optimal design, we use this method for the development of a 3-DOF spatial translational FPM. An experiment is carried out to determine the resolution and the repeatability of the developed FPM and verify the proposed evaluation method. The result shows that the method is suitable for the design of FPM for any desired resolution.
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06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
07.07.Tw Servo and control equipment; robots
45.40.Ln Robotics
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
back to top CONDENSED MATTER; MATERIALS

Sputter erosion measurements of titanium and molybdenum by cavity ring-down spectroscopy

V. Surla, P. J. Wilbur, M. Johnson, J. D. Williams, and A. P. Yalin

Rev. Sci. Instrum. 75, 3025 (2004); http://dx.doi.org/10.1063/1.1786354 (6 pages) | Cited 4 times

Online Publication Date: 14 September 2004

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We report cavity ring-down spectroscopy measurements of the gas-phase number density of titanium and molybdenum sputtered by argon ions. A neodymium: yttrium–aluminum–garnet pumped optical parametric oscillator laser system is used to probe optical absorption features of titanium and molybdenum in the 375–400 nm region. For an 18 mA ion beam current, and 750 eV ions, we find that the spatially averaged number density of sputtered atoms is 6.4±0.6×108 and 5.1±0.5×108 cm−3, for titanium and molybdenum, respectively. The measured number densities exhibit the expected linear behavior versus beam current, and are in reasonable agreement with values found from a simple sputtering model. Our current configuration yields number density detection limits of ∼ 9×106 and ∼ 7×105 cm−3, for titanium and molybdenum, respectively. The technique may ultimately provide a means to measure sputter erosion rates, which are of particular importance for the electric propulsion field.
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42.62.Fi Laser spectroscopy
81.65.Kn Corrosion protection
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
07.60.Rd Visible and ultraviolet spectrometers
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
42.65.Yj Optical parametric oscillators and amplifiers
back to top MICROSCOPY AND IMAGING

Sub-pico-Newton shear-force feedback system in air and liquid for scanning probe microscopy

Philippe Giaccari, Omar Sqalli, and Hans G. Limberger

Rev. Sci. Instrum. 75, 3031 (2004); http://dx.doi.org/10.1063/1.1786335 (3 pages)

Online Publication Date: 14 September 2004

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Scanning near-field optical microscopy requires a performant sensor to measure the tip-to-sample distance. In this article, we report on a shear force detection scheme for scanning near-field optical microscopy applications. It is based on an all fiber low-coherence interferometer. This setup makes possible the measurements of the tip oscillation amplitude of less than 50 pm both in air and aqueous environment with a precision of 160 fm/Hz1/2, thus demonstrating the ability to perform topographic measurements both in air and in liquids with a resolution better than 1 nm in tip-sample distance. Stable feedback in air and fluids is obtained with tip-sample interaction forces below 1 pN.
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07.10.Pz Instruments for strain, force, and torque
07.79.Fc Near-field scanning optical microscopes
68.37.Uv Near-field scanning microscopy and spectroscopy
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
back to top PARTICLE SOURCES, OPTICS AND ACCELERATION; PARTICLE DETECTORS

Compact electron beam ion source with high-TC bulk superconductors

Nobuyuki Nakamura, Yoichi Nakai, Yasuyuki Kanai, Ken-ichiro Komaki, Atsumi Endo, and Yasunori Yamazaki

Rev. Sci. Instrum. 75, 3034 (2004); http://dx.doi.org/10.1063/1.1786336 (5 pages) | Cited 9 times

Online Publication Date: 14 September 2004

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We have developed an electron beam ion source (EBIS) assembling three rings made of high-TC superconductor as a solenoid coil, which enables us to construct a “table-top” EBIS operated at the liquid N2 temperature with a strong magnetic field. Optimizing a pulse field magnetization procedure, the assembly yielded a magnetic field as high as 0.8 T under a persistent mode, which stably lasted more than two days. An electron beam of 12 keV-50 mA was compressed to a current density of about 300 A/cm2 and guided by the magnetic field along the axis of the drift tube. After exiting the drift tube, the electron beam was decelerated to 2 keV and collected with an electron collector with an efficiency of more than 99%. We have succeeded in extracting highly charged ions such as Ar17+ and Xe42+.
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74.72.-h Cuprate superconductors
84.71.Ba Superconducting magnets; magnetic levitation devices
07.77.Ka Charged-particle beam sources and detectors
29.25.Ni Ion sources: positive and negative
74.25.Ha Magnetic properties including vortex structures and related phenomena
74.25.Sv Critical currents
back to top CHEMISTRY

Simple ortho-para hydrogen and para-ortho deuterium converter for matrix isolation spectroscopy

Lester Andrews and Xuefeng Wang

Rev. Sci. Instrum. 75, 3039 (2004); http://dx.doi.org/10.1063/1.1786332 (6 pages) | Cited 10 times

Online Publication Date: 14 September 2004

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A copper tube containing catalyst immersed in the cold gas above liquid helium is used to convert normal H2 and D2 to high purity J = 0 samples. The converted samples are sublimed directly from 12–16 K catalyst to the 4 K matrix substrate for recording infrared spectra. The decrease of infrared absorptions due to J = 1 isomer perturbations on the major J = 0 species bands show that solid samples >99% in the J = 0 species are formed. Such high purity p-H2 and o-D2 subjected to Tesla coil discharge during condensation at 4 K sustain a 2%–8% decrease in the J = 0 species population depending on the discharge pressure. We also show that orthodeuterium is an excellent matrix host.
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07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
33.20.Ea Infrared spectra
33.50.Hv Radiationless transitions, quenching
78.30.-j Infrared and Raman spectra
back to top GENERAL INSTRUMENTS

Simple force balance accelerometer/seismometer based on a tuning fork displacement sensor

D. Stuart-Watson and J. Tapson

Rev. Sci. Instrum. 75, 3045 (2004); http://dx.doi.org/10.1063/1.1786333 (5 pages) | Cited 4 times

Online Publication Date: 14 September 2004

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Seismometers and microelectromechanical system accelerometers use the force-balance principle to obtain measurements. In these instruments the displacement of a mass object by an unknown force is sensed using a very high-resolution displacement sensor. The position of the object is then stabilized by applying an equal and opposite force to it. The magnitude of the stabilizing force is easily measured, and is assumed to be equivalent to the unknown force. These systems are critically dependent on the displacement sensor. In this article we use a resonant quartz tuning fork as the sensor. The tuning fork is operated so that its oscillation is lightly damped by the proximity of the movable mass object. Changes in the position of the mass object cause changes in the phase of the fork’s resonance; this is used as the feedback variable in controlling the mass position. We have developed an acceleration sensor using this principle. The mass object is a piezoelectric bimorph diaphragm which is anchored around its perimeter, allowing direct electronic control of the displacement of its center. The tuning fork is brought very close to the diaphragm center, and is connected into a self-oscillating feedback circuit which has phase and amplitude as outputs. The diaphragm position is adjusted by a feedback loop, using phase as the feedback variable, to keep it in a constant position with respect to the tuning fork. The measured noise for this sensor is approximately 10.0 mg in a bandwidth of 100 Hz, which is substantially better than commercial systems of equivalent cost and size.
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07.10.Pz Instruments for strain, force, and torque
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
06.30.Gv Velocity, acceleration, and rotation
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
07.10.Cm Micromechanical devices and systems
back to top CHEMISTRY

A three-dimensional electron spin resonance microscope

Aharon Blank, Curt R. Dunnam, Peter P. Borbat, and Jack H. Freed

Rev. Sci. Instrum. 75, 3050 (2004); http://dx.doi.org/10.1063/1.1786353 (12 pages) | Cited 13 times

Online Publication Date: 15 September 2004

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An electron spin resonance (ESR) imaging system, capable of acquiring three-dimensional (3D) images with a resolution of ∼ 10×10×30 μm in a few minutes of acquisition, is presented. This ESR microscope employs a commercial continuous wave ESR spectrometer, working at 9.1 GHz, in conjunction with a miniature imaging probe (resonator+gradient coils), gradient current drivers, and control software. The system can acquire the image of a small ( ∼ 1.5×1.5×0.25 mm) sample either by the modulated field gradient method, the projection reconstruction method, or by a combination of the two. A short discussion regarding the resolution of the modulated field gradient method in two-dimensional (2D) and 3D imaging is given. Detailed descriptions of the various system components are provided, along with several examples of 2D and 3D images that demonstrate the capabilities of the system.
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07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques
07.05.Pj Image processing
back to top
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A multiparameter data acquisition system based on universal serial bus interface for electron momentum spectrometer

C. G. Ning, J. K. Deng, G. L. Su, H. Zhou, and X. G. Ren

Rev. Sci. Instrum. 75, 3062 (2004); http://dx.doi.org/10.1063/1.1781384 (3 pages) | Cited 11 times

Online Publication Date: 15 September 2004

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A versatile multiparameter data acquisition system based on universal serial bus (USB) interface was designed and has been used on the electron momentum spectromenter. Digitized data were first buffered in a FIFO memory in an event-by-event mode with a check bit, and then transferred to computer through the USB interface. USB interface combined with a microcontroller unit provides much flexibility for data acquisition and experimental controls. The operation performance of the system is demonstrated in the measurement of electron momentum spectra of CH2F2 molecules.
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07.81.+a Electron and ion spectrometers
07.05.Hd Data acquisition: hardware and software
07.05.Wr Computer interfaces
84.30.Sk Pulse and digital circuits

Rapid and convenient method for preparing masters for microcontact printing with 1–12 μm features

Lloyd W. Zilch, Ghaleb A. Husseini, Yit-Yian Lua, Michael V. Lee, Kevin R. Gertsch, Bennion R. Cannon, Robert M. Perry, Eric T. Sevy, Matthew C. Asplund, Adam T. Woolley, and Matthew R. Linford

Rev. Sci. Instrum. 75, 3065 (2004); http://dx.doi.org/10.1063/1.1781385 (3 pages) | Cited 6 times

Online Publication Date: 15 September 2004

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Mechanical scribing can be employed to create surfaces with recessed features. Through replica molding elastomeric copies of these scribed surfaces are created that function as stamps for microcontact printing. It is shown that this new method for creating masters for microcontact printing can be performed with a computer-controlled milling machine (CNC), making this method particularly straightforward and accessible to a large technical community that does not need to work in a particle free environment. Thus, no clean room, or other specialized equipment is required, as is commonly needed to prepare masters. Time-of-flight secondary ion mass spectrometry confirms surface pattering by this method. Finally, it is shown that feature size in the scribed master can be controlled by varying the force on the tip during scribing.
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81.16.Nd Micro- and nanolithography
81.20.Wk Machining, milling
81.10.Fq Growth from melts; zone melting and refining
07.10.Cm Micromechanical devices and systems
07.75.+h Mass spectrometers

Development of multicathode high flux metal ion plasma sources in Korea

Do-Yun Kim, Eui-Wan Lee, and Myoung-Bok Lee

Rev. Sci. Instrum. 75, 3068 (2004); http://dx.doi.org/10.1063/1.1783593 (3 pages)

Online Publication Date: 15 September 2004

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Multicathode high flux metal plasma ion sources were self-developed and its performance was proved to be appropriate for the high-purity ion implantation and thin-film deposition. As key results of self-design, a bipolar pulse power supply with a peak voltage of 250 V, a repetition rate of 20 Hz, and a pulse width of 100 μs showed an output current of 2 kA and an average power of 2 kW and the operational plasma flux of multicathode ion source was well sustained even at an ion current of about 5 A. A high-voltage pulse generator was employed as a trigger power supply producing a peak voltage of 12 kV, peak current of 50 A, and stable repetition rate of 20 Hz.
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52.50.Dg Plasma sources
52.77.Dq Plasma-based ion implantation and deposition
68.49.Sf Ion scattering from surfaces (charge transfer, sputtering, SIMS)
07.77.Ka Charged-particle beam sources and detectors

Phase boundary detection for dilution refrigerators

E. ter Haar and R. V. Martin

Rev. Sci. Instrum. 75, 3071 (2004); http://dx.doi.org/10.1063/1.1784568 (3 pages)

Online Publication Date: 15 September 2004

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We describe a device to conveniently measure the positions of the phase boundaries in a dilution refrigerator. We show how a simple modification of a standard capacitive level gauge (segmentation of one of the electrodes) permits a direct calibration of the capacitance versus phase boundary position. We compare this direct calibration with the indirect procedure that must be adopted for a conventional capacitive level gauge. The device facilitates the correct adjustment of the 3He/4He fraction in the dilution refrigerator.
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07.30.Dz Vacuum gauges
84.32.Tt Capacitors
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment
06.20.F- Units and standards
07.68.+m Photography, photographic instruments; xerography

Thermal contact conductance between solid interfaces under low temperature and vacuum

Youming Xiao, Heng Sun, Lie Xu, Haidong Feng, and Hongmei Zhu

Rev. Sci. Instrum. 75, 3074 (2004); http://dx.doi.org/10.1063/1.1786356 (3 pages) | Cited 3 times

Online Publication Date: 15 September 2004

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In this article, an experimental device used for thermal contact conductance tests under low temperature and vacuum was demonstrated in detail, which may be used to simulate the real environment of some solid materials, such as stainless steel, or aluminum in a space satellite. Thermal contact conductance experiments of stainless steel, of aluminum, and between stainless steel and aluminum were made for 0.02 Pa and 100–330 K. The relationships of thermal contact conductance to the contact loading pressure and to the temperature were measured. It is demonstrated that the thermal contact conductance between stainless steel, aluminum, between stainless steel, and aluminum contacts rises with the temperature increase of the contact interface, as well as the loading pressure increase of the contact interface. The thermal contact conductance of aluminum is larger than that of stainless steel for the same temperature and same loading pressure of the contact interface. The thermal contact conductance between stainless steel and aluminum is close to that between aluminum contacts at the same temperature and same loading pressure of the contact interface.
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07.20.-n Thermal instruments and apparatus

High performance laser shutter using a hard disk drive voice-coil actuator

L. P. Maguire, S. Szilagyi, and R. E. Scholten

Rev. Sci. Instrum. 75, 3077 (2004); http://dx.doi.org/10.1063/1.1786331 (3 pages) | Cited 12 times

Online Publication Date: 15 September 2004

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Voice-coil motors in computer hard disk drives are shown to make excellent mechanical shutters for light beams. Shutter speeds in excess of 10 mm/ms are attained, allowing switching of a focused beam in under 10 μs. Aperture size can be up to 32 mm. As little as 1 mW of power is required for shutter operation. The shutter can be driven with a sinusoidal signal to switch at up to 100 Hz. The shutter is also suitable for x-ray applications. Essentially no modification of the drive or actuator is required for most types of operation.
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85.70.Li Other magnetic recording and storage devices (including tapes, disks, and drums)
42.60.-v Laser optical systems: design and operation
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