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May 2006

Volume 77, Issue 5, Articles (05xxxx)

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Determination of the absolute fluence profile in pulsed laser processing using melt-induced phase changes in an amorphous silicon thin film

J. P. Leonard

Rev. Sci. Instrum. 77, 053101 (2006); http://dx.doi.org/10.1063/1.2198727 (6 pages) | Cited 3 times

Online Publication Date: 5 May 2006

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A simple silicon-based thin film multilayer configuration is used to obtain measurements of beam profiles in a pulsed excimer projection system with fluence levels similar to melt-mediated materials processing. Abrupt transitions between amorphous and polycrystalline phases are found at the onset of melting, and at the attainment of complete melting in a thin silicon film encapsulated between SiO2 layers. When combined with a standard technique for absolute determination of fluence under flood irradiation using bulk melting of silicon, a device for measurement of the two-dimensional absolute fluence profile is realized. With this technique fluence profiles can be estimated within ±25 mJ/cm2 at a lateral spatial resolution of 0.5 μm.
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42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.62.-b Laser applications
64.70.D- Solid-liquid transitions
42.55.Lt Gas lasers including excimer and metal-vapor lasers
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.82.Fk Semiconductors
79.20.Ds Laser-beam impact phenomena

Resonant inelastic hard x-ray scattering with diced analyzer crystals and position-sensitive detectors

S. Huotari, F. Albergamo, Gy. Vankó, R. Verbeni, and G. Monaco

Rev. Sci. Instrum. 77, 053102 (2006); http://dx.doi.org/10.1063/1.2198805 (6 pages) | Cited 9 times

Online Publication Date: 9 May 2006

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A novel design of a high-resolution spectrometer is proposed for emission spectroscopy and resonant inelastic hard x-ray scattering applications. The spectrometer is based on a Rowland circle geometry with a diced analyzer crystal and a position-sensitive detector. The individual flat crystallites of the diced analyzer introduce a well-defined linear position-energy relationship within the analyzer focus. This effect can be exploited to measure emission spectra with an unprecedented resolution. For demonstration, a spectrometer was constructed using a diced Si(553) analyzer working at the Cu K edge with an intrinsic resolution of 60 meV. With the proposed design, spectrometers operating at the K edges of 3d transition metals can have intrinsic resolutions below 100 meV even with analyzer crystals not working in Bragg-backscattering conditions.
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07.85.Nc X-ray and γ-ray spectrometers

Hartmann-Shack wave front measurements for real time determination of laser beam propagation parameters

B. Schäfer, M. Lübbecke, and K. Mann

Rev. Sci. Instrum. 77, 053103 (2006); http://dx.doi.org/10.1063/1.2198795 (8 pages) | Cited 4 times

Online Publication Date: 18 May 2006

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The suitability of the Hartmann-Shack technique for the determination of the propagation parameters of a laser beam is faced against the well known caustic approach according to the ISO 11146 standard. A He–Ne laser (543 nm) was chosen as test beam, both in its fundamental mode as well as after intentional distortion, introducing a moderate amount of spherical aberration. Results are given for the most important beam parameters M2, divergence, and beam widths, indicating an agreement of better than 10% and for adapted beam diameter <5%. Furthermore, the theoretical background, pros and cons, as well as some features of the software implementation for the Hartmann-Shack sensor are briefly reviewed.
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07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
06.20.fb Standards and calibration
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Near-infrared Fourier transform photoluminescence spectrometer with tunable excitation for the study of single-walled carbon nanotubes

Timothy J. McDonald, Marcus Jones, Chaiwat Engtrakul, Randy J. Ellingson, Garry Rumbles, and Michael J. Heben

Rev. Sci. Instrum. 77, 053104 (2006); http://dx.doi.org/10.1063/1.2198748 (6 pages) | Cited 3 times

Online Publication Date: 19 May 2006

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A fast, sensitive, automated Fourier transform (FT) photoluminescence (PL) spectrometer with tunable excitation has been developed for analyzing carbon nanotube suspensions over a wide spectral range. A commercially available spectrometer was modified by the addition of a tunable excitation source, custom collection optics, and computer software to provide control and automated data collection. The apparatus enables excitation from 400 to 1100 nm and detection from 825 to 1700 nm, permitting the analysis of virtually all semiconducting single-walled nanotubes (SWNTs), including those produced by the high pressure carbon monoxide conversion and laser processes. The FT approach provides an excellent combination of high sensitivity and fast measurement. The speed advantage exists because the entire emission spectrum is collected simultaneously, while the sensitivity advantage stems from the high optical throughput. The high sensitivity is demonstrated in the measurement of very dilute SWNT suspensions and the observation of novel spectral features, and the speed is demonstrated by measuring the real-time changes in the SWNT PL during rebundling. This contribution describes the assembly of components, the methods for automating data collection, and the procedures for correcting the wavelength-dependent excitation intensity and the interferometer and detector responses.
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07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
78.67.Ch Nanotubes
78.55.Hx Other solid inorganic materials

Energy calibration of superconducting transition edge sensors for x-ray detection using pulse analysis

C. Hollerith, B. Simmnacher, R. Weiland, F. v. Feilitzsch, C. Isaila, J. Jochum, W. Potzel, J. Höhne, K. Phelan, D. Wernicke, and T. May

Rev. Sci. Instrum. 77, 053105 (2006); http://dx.doi.org/10.1063/1.2202911 (6 pages) | Cited 2 times

Online Publication Date: 26 May 2006

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Transition edge sensors (TESs) have been developed to be used as high-resolution x-ray detectors. They show excellent energy resolution and can be used in many applications. TESs are a special kind of calorimeters that can determine small temperature changes after x-ray absorption. Such a temperature change causes a strong resistance change (superconducting to normal-conducting phase transition) that can be measured. The energy calibration of a TES based spectrometer is problematic due to the nonlinear behavior of the detector response. In this article, a method is introduced to calibrate the energy scale of TES spectra. This is accomplished by calculating the energy dependence of the response of the detector operated in electrothermal feedback mode. Using this method a calibration accuracy of a few eV for an x-ray energy of 6 keV can be achieved. Examples of energy dispersive x-ray spectroscopy (EDS) measurements demonstrate the high quality of this method for everyday use of TES EDS detectors in material analysis. However, because the method relies only on a few very general assumptions, it should also be useful for other kinds of TES detectors.
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07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
07.20.Fw Calorimeters
07.85.Nc X-ray and γ-ray spectrometers
78.70.Dm X-ray absorption spectra
82.80.Ej X-ray, Mössbauer, and other γ-ray spectroscopic analysis methods

Area-scan camera for terahertz holography

David Crawley, Stafford Withington, and Jelena Obradovic

Rev. Sci. Instrum. 77, 053106 (2006); http://dx.doi.org/10.1063/1.2185547 (4 pages) | Cited 5 times

Online Publication Date: 26 May 2006

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Terahertz technology has shown great promise in recent years with a large number of applications being demonstrated, as well improvements in detectors, sources, imaging schemes. Many of the proposed applications, however, will require compact imaging systems that have the capability to capture two- or three-dimensional images. We propose an area-scan configuration that has the potential to meet this need that could be used to generate three-dimensional images through holographic techniques. We present data that verify the feasibility of our scheme.
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42.40.Kw Holographic interferometry; other holographic techniques
42.79.Pw Imaging detectors and sensors
07.57.-c Infrared, submillimeter wave, microwave and radiowave instruments and equipment

Heterodyne double-channel polarimeter for mapping birefringence and thickness of flat glass panels

Vladimir V. Protopopov, Sunghoon Cho, Kwangso Kim, Sukwon Lee, Hyuk Kim, and Daesuk Kim

Rev. Sci. Instrum. 77, 053107 (2006); http://dx.doi.org/10.1063/1.2202916 (6 pages) | Cited 2 times

Online Publication Date: 30 May 2006

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A new cross-polarized heterodyne optical technique is developed for two-dimensional (2D) simultaneous mapping of both birefringence and thickness variations in large flat glass panels commonly used in liquid-crystal displays (LCDs). Weak depolarization of a linearly polarized probe beam due to glass birefringence is detected by means of heterodyne mixing of the two cross-polarized and frequency shifted waves generated by Zeeman-type laser. Amplitude variations of the transmitted laser beam due to interference of the partial waves reflected from the both sides of a sample provide information about glass thickness. Measurements are being performed at the intermediate frequency of 2.3 MHz, providing several orders of magnitude higher speed of data acquisition with respect to traditional polarimeters. That high speed of measurements makes it possible to perform quality assessment of LCD glass panels not only in few randomly chosen points as it was in common practice before but to obtain entire 2D maps of both birefringence and thickness variations with millimeter scale spatial resolution. The medium-scale prototype of the LCD glass inspection system is developed and tested. Design and performance of the prototype are described.
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07.60.Fs Polarimeters and ellipsometers
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
42.79.Kr Display devices, liquid-crystal devices
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
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Response of a delta-doped charge-coupled device to low energy protons and nitrogen ions

S. T. Lepri, Shouleh Nikzad, T. Jones, J. Blacksberg, and T. H. Zurbuchen

Rev. Sci. Instrum. 77, 053301 (2006); http://dx.doi.org/10.1063/1.2198829 (9 pages) | Cited 2 times

Online Publication Date: 19 May 2006

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We present the results of a study of the response of a delta-doped charge-coupled device (CCD) exposed to ions with energies less than 10 keV. The study of ions in the solar wind, the majority having energies in the 1–5 keV range, has proven to be vital in understanding the solar atmosphere and the near Earth space environment. Delta-doped CCD technology has essentially removed the dead layer of the silicon detector. Using the delta-doped detector, we are able to detect H+ and N+ ions with energies ranging from 1 to 10 keV in the laboratory. This is a remarkable improvement in the low energy detection threshold over conventional solid-state detectors, such as those used in space sensors, one example being the solar wind ion composition spectrometer (SWICS) on the Advanced Composition Explorer spacecraft, which can only detect ions with energies greater than 30 keV because of the solid-state detector’s minimum energy threshold. Because this threshold is much higher than the average energy of the solar wind ions, the SWICS instrument employs a bulky high voltage postacceleration stage that accelerates ions above the 30 keV detection threshold. This stage is massive, exposes the instrument to hazardous high voltages, and is therefore problematic both in terms of price and its impact on spacecraft resources. Adaptation of delta-doping technology in future space missions may be successful in reducing the need for heavy postacceleration stages allowing for miniaturization of space-borne ion detectors.
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29.40.Gx Tracking and position-sensitive detectors
96.60.Vg Particle emission, solar wind
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Dispersion interferometer based on a CO2 laser for TEXTOR and burning plasma experiments

P. A. Bagryansky, A. D. Khilchenko, A. N. Kvashnin, A. A. Lizunov, R. V. Voskoboynikov, A. L. Solomakhin, and H. R. Koslowski

Rev. Sci. Instrum. 77, 053501 (2006); http://dx.doi.org/10.1063/1.2202922 (7 pages) | Cited 13 times

Online Publication Date: 26 May 2006

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A dispersion interferometer based on a continuous-wave CO2 laser source (λ = 9.57 μm) with double plasma passage for measurements of the line-integrated electron density in the TEXTOR tokamak and the GDT linear system has been developed and tested in experiments. A sensitivity of 〈nel〉min = 2×1017 m−2 and a temporal resolution of 1 ms have been achieved. The interferometer does not need any rigid frame for vibration insulation. Its basic components are installed compactly on an optical bench placed on a stable support outside of the torus. The possibility for the development of a multichannel dispersion interferometer for the next generation of fusion devices (e.g., W7-X, ITER) is discussed.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.55.Fa Tokamaks, spherical tokamaks
52.25.-b Plasma properties
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Lateral force calibration in atomic force microscopy: A new lateral force calibration method and general guidelines for optimization

Rachel J. Cannara, Michael Eglin, and Robert W. Carpick

Rev. Sci. Instrum. 77, 053701 (2006); http://dx.doi.org/10.1063/1.2198768 (11 pages) | Cited 28 times

Online Publication Date: 5 May 2006

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Proper force calibration is a critical step in atomic and lateral force microscopies (AFM/LFM). The recently published torsional Sader method [ C. P. Green et al., Rev. Sci. Instrum. 75, 1988 (2004) ] facilitates the calculation of torsional spring constants of rectangular AFM cantilevers by eliminating the need to obtain information or make assumptions regarding the cantilever’s material properties and thickness, both of which are difficult to measure. Complete force calibration of the lateral signal in LFM requires measurement of the lateral signal deflection sensitivity as well. In this article, we introduce a complete lateral force calibration procedure that employs the torsional Sader method and does not require making contact between the tip and any sample. In this method, a colloidal sphere is attached to a “test” cantilever of the same width, but different length and material as the “target” cantilever of interest. The lateral signal sensitivity is calibrated by loading the colloidal sphere laterally against a vertical sidewall. The signal sensitivity for the target cantilever is then corrected for the tip length, total signal strength, and in-plane bending of the cantilevers. We discuss the advantages and disadvantages of this approach in comparison with the other established lateral force calibration techniques, and make a direct comparison with the “wedge” calibration method. The methods agree to within 5%. The propagation of errors is explicitly considered for both methods and the sources of disagreement discussed. Finally, we show that the lateral signal sensitivity is substantially reduced when the laser spot is not centered on the detector.
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07.79.Lh Atomic force microscopes
06.20.fb Standards and calibration
07.10.Pz Instruments for strain, force, and torque

Compact UHV system for fabrication and in situ analysis of electron beam deposited structures using a focused low energy electron beam

Y. Kakefuda, Y. Yamashita, K. Mukai, and J. Yoshinobu

Rev. Sci. Instrum. 77, 053702 (2006); http://dx.doi.org/10.1063/1.2198810 (5 pages) | Cited 4 times

Online Publication Date: 5 May 2006

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A compact UHV system was developed in order to fabricate and analyze micro- and nanostructures on surfaces in situ. The system includes a low energy electron gun which provides a minimum spot size of ∼ 25 nm in a diameter using electrostatic lenses, a cylindrical mirror analyzer for Auger electron spectroscopy (AES) and electron energy loss spectroscopy (EELS), a low energy electron diffraction (LEED) optics, and a scintillation counter for scanning electron microscopy. Thus, we can analyze electronic states of specific microstructures on surfaces. In addition, we can fabricate microscopic structures artificially by means of scanning a focused electron beam. In this article, first we show the performance of the present analysis system. Next, we provide an example of the fabrication of iron microstructures by electron-induced deposition of iron pentacarbonyl [Fe(CO)5]. We successfully analyzed the amount and chemical states of deposited iron by AES in situ. We also investigated coverage dependence of electronic structure and surface periodic structure by EELS and LEED measurements, respectively. Thus, this system enables us to fabricate and analyze microscopic structures on surfaces in situ.
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07.30.-t Vacuum apparatus
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
41.85.Ne Electrostatic lenses, septa
61.05.jh Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)

Control of microcantilevers in dynamic force microscopy using time delayed feedback

Kohei Yamasue and Takashi Hikihara

Rev. Sci. Instrum. 77, 053703 (2006); http://dx.doi.org/10.1063/1.2200747 (6 pages) | Cited 7 times

Online Publication Date: 16 May 2006

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It has been recently shown that microcantilever sensors in dynamic force microscopes possibly exhibit chaotic oscillations due to the nonlinear tip-sample interaction force. In this article, we propose elimination of the chaotic oscillations using the time delayed feedback control method, which has an ability to stabilize unstable periodic orbits embedded in chaotic attractors. An extended operating range of the microscopes is numerically estimated by stability analysis of the target periodic oscillation. We also discuss an improved transient response of oscillation, which allows us to accelerate the scanning rate of the microscopes without reducing their force sensitivity.
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07.10.Cm Micromechanical devices and systems
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
07.79.Lh Atomic force microscopes

Direct tip-position control using magnetic actuation for achieving fast scanning in tapping mode atomic force microscopy

G. R. Jayanth, Younkoo Jeong, and Chia-Hsiang Menq

Rev. Sci. Instrum. 77, 053704 (2006); http://dx.doi.org/10.1063/1.2200874 (7 pages) | Cited 9 times

Online Publication Date: 19 May 2006

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This article presents the development of a faster control loop for oscillation amplitude regulation in tapping mode operation of atomic force microscopy. Two techniques in relation to actuation and measurement are developed, that together significantly increase the bandwidth of the control loop. Firstly, magnetic actuation is employed to directly control the tip position of the cantilever to improve both the speed and the dynamics of the positioning system. Secondly, the signal path for oscillation amplitude regulation is separated from that for topography estimation in order to eliminate measurement delay that degrades the performance of the feedback loop. As a result, the phase-crossover frequency and gain margin of the control system are both increased, leading to a faster and more stable system. Two experiments are performed, one in air and the other in aqueous solution, to compare the developed control system with a commercial one and demonstrate the improvement. The results verify that the combination of the two techniques along with other existing methods eliminates all limitations associated with the instrument for the purpose of oscillation amplitude regulation, which is therewith dictated by the bandwidth of the cantilever.
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07.79.Lh Atomic force microscopes
02.30.Yy Control theory

Observation of low-temperature object by phase-contrast x-ray imaging: Nondestructive imaging of air clathrate hydrates at 233 K

Satoshi Takeya, Kazumasa Honda, Akio Yoneyama, Yasuharu Hirai, Junichi Okuyama, Takeo Hondoh, Kazuyuki Hyodo, and Tohoru Takeda

Rev. Sci. Instrum. 77, 053705 (2006); http://dx.doi.org/10.1063/1.2200751 (4 pages) | Cited 4 times

Online Publication Date: 26 May 2006

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A cryochamber and a liquid cell that are designed for nondestructive three dimensional observations and arranged in a two-crystal x-ray interferometer expand the use of phase-contrast x-ray imaging that could only be performed at room temperature in previous studies to a new temperature range of 190 K to room temperature. The methyl acetate in the liquid cell prevents undesirable sample outline contrasts and enables internal observations. Both a nondestructive observation and a highly accurate absolute density of the materials under low-temperature conditions can be obtained with a single measurement using this new technique. A three dimensional x-ray computed tomography (x-ray CT) of the air clathrate hydrate in the hexagonal ice drilled from Dome Fuji in Antarctica is shown, and the density of the air hydrate is estimated to be 0.937(3) g/cm3 at 233 K.
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07.85.-m X- and γ-ray instruments
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment

Measurement of the absolute separation for atomic force microscopy measurements in the presence of adsorbed polymer

Clayton T. McKee, Wade K. J. Mosse, and William A. Ducker

Rev. Sci. Instrum. 77, 053706 (2006); http://dx.doi.org/10.1063/1.2202929 (6 pages)

Online Publication Date: 26 May 2006

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We demonstrate that the absolute separation between an atomic force microscope (AFM) tip and a solid substrate can be measured in the presence of an irreversibly adsorbed polymer film. The separation is obtained from the analysis of a scattered evanescent wave that is generated at the surface of the solid. By comparing our scattering measurements to conventional AFM measurements, we also show an example where a conventional AFM measurement gives the incorrect force-distance profile. We validate the measurement of separation from scattering by examining the force-separation profile in the presence of surfactant solution. This validation is possible because the tip can be used to desorb the surfactant film that forms in surfactant solution, so we are able to measure both the scattering and the cantilever deflection when the tip is in contact with the solid substrate. The main limitation of our technique now is the lack of a rigorous method for predicting the intensity of scattering from the tip in contact with a solid that is coated with a film.
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07.79.Lh Atomic force microscopes
68.37.Ps Atomic force microscopy (AFM)
68.43.Mn Adsorption kinetics
82.70.Uv Surfactants, micellar solutions, vesicles, lamellae, amphiphilic systems, (hydrophilic and hydrophobic interactions)
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Noncontact surface tension and viscosity measurements of molten oxides with a pressurized hybrid electrostatic-aerodynamic levitator

Takehiko Ishikawa, Jianding Yu, and Paul-François Paradis

Rev. Sci. Instrum. 77, 053901 (2006); http://dx.doi.org/10.1063/1.2198787 (4 pages) | Cited 3 times

Online Publication Date: 3 May 2006

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In order to measure the surface tension and the viscosity of molten oxides, the oscillation drop technique has been applied on a pressurized hybrid electrostatic-aerodynamic levitator. To suppress the electrical discharge between the top and bottom electrodes, the drop excitation method which has been used with high vacuum electrostatic levitators has been modified. As a demonstration, the surface tension and viscosity of liquid BaTiO3 were measured using this new method. Over the 1500–2000 K interval, the surface tension was measured as γ(T) = 349−0.03 (T−Tm) (10−3 N/m), where Tm = 1893 K is the melting temperature. Similarly, the viscosity was determined as η(T) = 0.53 exp[5.35×104/(RT)](10−3 Pa s) over the same temperature interval.
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47.80.-v Instrumentation and measurement methods in fluid dynamics
68.03.Cd Surface tension and related phenomena
66.20.-d Viscosity of liquids; diffusive momentum transport
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
64.70.D- Solid-liquid transitions

New composite reed vibration method to measure the mechanical spectra of liquids

X. N. Ying, Y. H. Yuan, L. Zhang, Y. N. Huang, Y. N. Wang, X. L. Wang, D. S. Zhou, and G. Xue

Rev. Sci. Instrum. 77, 053902 (2006); http://dx.doi.org/10.1063/1.2198833 (12 pages) | Cited 6 times

Online Publication Date: 10 May 2006

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A new experimental method describing the determination of the mechanical spectra (complex Young’s modulus Y* = Y′+iY″ versus temperature) of materials from the liquid to the glassy state, including the glass transition, is reported. The conventional vibration-reed method developed for solids is extended to composite systems consisting of a reed substrate and a deposited material. Mathematical expressions for the evaluation of the mechanical spectrum of the deposited material are obtained by solving either directly the vibrating equation of the nonuniform reed, or that of an equivalent uniform reed, with new length and stiffness, using a coordinate transformation. The mechanical spectra of glycerol and 1,2-propanediol carbonate covering the liquid and the glassy state are presented as examples in this work. The glass transitions of these two kinds of materials, as well as the recrystallization, melting and, evaporation processes of 1,2-propanediol carbonate, are identified in the respective spectra.
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07.10.Fq Vibration isolation
46.80.+j Measurement methods and techniques in continuum mechanics of solids
81.40.Jj Elasticity and anelasticity, stress-strain relations
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
64.70.D- Solid-liquid transitions
64.70.F- Liquid-vapor transitions

Levitation apparatus for neutron diffraction investigations on high temperature liquids

Louis Hennet, Irina Pozdnyakova, Aleksei Bytchkov, Viviana Cristiglio, Pierre Palleau, Henry E. Fischer, Gabriel J. Cuello, Mark Johnson, Philippe Melin, Didier Zanghi, Séverine Brassamin, Jean-François Brun, David L. Price, and Marie-Louise Saboungi

Rev. Sci. Instrum. 77, 053903 (2006); http://dx.doi.org/10.1063/1.2200756 (7 pages) | Cited 14 times

Online Publication Date: 19 May 2006

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We describe a new high temperature environment based on aerodynamic levitation and laser heating designed for neutron scattering experiments up to 3000 °C. The sample is heated to the desired temperature with three CO2 lasers from different directions in order to obtain a homogeneous temperature distribution. The apparent temperature of the sample is measured with an optical pyrometer, and two video cameras are employed to monitor the sample behavior during heating. The levitation setup is enclosed in a vacuum-tight chamber, enabling a high degree of gas purity and a reproducible sample environment for structural investigations on both oxide and metallic melts. High-quality neutron diffraction data have been obtained on liquid Y3Al5O12 and ZrNi alloy for relatively short counting times (1.5 h).
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61.05.fg Neutron scattering (including small-angle scattering)
61.05.fm Neutron diffraction
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
81.40.Gh Other heat and thermomechanical treatments

Facile, nanoresolution translation setup for the growth of organic crystal meta-nitroaniline by Bridgman technique

M. Jayaprakasan, V. Kannan, R. Bairava Ganesh, and P. Ramasamy

Rev. Sci. Instrum. 77, 053904 (2006); http://dx.doi.org/10.1063/1.2202930 (5 pages)

Online Publication Date: 22 May 2006

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A nanoresolution translation setup for Bridgman technique was designed and employed for the growth of organic crystal meta-nitroaniline using stepper motor. Ultrasmooth and vibration-free translation was accomplished in microstepping mode. Linear translation of 40 nm per microstep has been achieved. A potential molecular organic crystal meta-nitroaniline of 18 mm diameter and 80 mm length has been successfully grown with good optical quality. Ultraviolet-visible-near-infrared spectra showed excellent transmission from 1100 to 520 nm. Etching studies reveal lower defect density.
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81.10.Fq Growth from melts; zone melting and refining
78.40.Me Organic compounds and polymers
78.30.Jw Organic compounds, polymers
81.65.Cf Surface cleaning, etching, patterning
61.72.-y Defects and impurities in crystals; microstructure

Dual-frequency ferromagnetic resonance

Y. Guan and W. E. Bailey

Rev. Sci. Instrum. 77, 053905 (2006); http://dx.doi.org/10.1063/1.2204907 (3 pages) | Cited 2 times

Online Publication Date: 30 May 2006

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We describe a new experimental technique to investigate coupling effects between different layers or modes in ferromagnetic resonance (FMR). Dual FMR frequencies are excited (2–8 GHz) simultaneously and detected selectively in a broadband rf circuit using lock-in amplifier detection at separate modulation frequencies.
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06.30.Ka Basic electromagnetic quantities
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
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Wideband measurement of shear induced birefringence by quadrupole method

M. Hosoda, K. Horii, H. Nomura, and K. Sakai

Rev. Sci. Instrum. 77, 054101 (2006); http://dx.doi.org/10.1063/1.2200764 (4 pages) | Cited 1 time

Online Publication Date: 22 May 2006

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We developed a new method for the measurement of the dynamic birefringence induced by the alternating shear deformation in fluid samples. A quadrupole piezoactuator generates the pure shear deformation in the frequency range from 1 Hz to 5 kHz and causes the molecular orientation, or the anisotropic conformation of polymers and molecular associations, which is observed by the optical ellipsometry technique. The spectrum of the shear-induced birefringence observed for the isotropic phase of the liquid crystal p‐n-hexyl p′-cyanobiphenyl (6CB) shows linear dependence on the frequency up to 5 kHz, corroborating the effective band of the experimental system. The sensitivity of the system was demonstrated by the quantitative measurement of the birefringence for the isotropic phase of p‐n-pentyl p′-cyanobiphenyl (5CB). The system was also applied to the aqueous solution of the worm such as micelles and the result shows the relaxation of shear induced birefringence at around 10 Hz, which agrees well with the previous reports.
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62.10.+s Mechanical properties of liquids
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
61.30.Eb Experimental determinations of smectic, nematic, cholesteric, and other structures
61.30.Vx Polymer liquid crystals
78.20.Fm Birefringence

Molecular beam mass spectrometer equipped with a catalytic wall reactor for in situ studies in high temperature catalysis research

R. Horn, K. Ihmann, J. Ihmann, F. C. Jentoft, M. Geske, A. Taha, K. Pelzer, and R. Schlögl

Rev. Sci. Instrum. 77, 054102 (2006); http://dx.doi.org/10.1063/1.2200872 (9 pages) | Cited 1 time

Online Publication Date: 24 May 2006

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A newly developed apparatus combining a molecular beam mass spectrometer and a catalytic wall reactor is described. The setup has been developed for in situ studies of high temperature catalytic reactions (>1000 °C), which involve besides surface reactions also gas phase reactions in their mechanism. The goal is to identify gas phase radicals by threshold ionization. A tubular reactor, made from the catalytic material, is positioned in a vacuum chamber. Expansion of the gas through a 100 μm sampling orifice in the reactor wall into differentially pumped nozzle, skimmer, and collimator chambers leads to the formation of a molecular beam. A quadrupole mass spectrometer with electron impact ion source designed for molecular beam inlet and threshold ionization measurements is used as the analyzer. The sampling time from nozzle to detector is estimated to be less than 10 ms. A detection time resolution of up to 20 ms can be reached. The temperature of the reactor is measured by pyrometry. Besides a detailed description of the setup components and the physical background of the method, this article presents measurements showing the performance of the apparatus. After deriving the shape and width of the energy spread of the ionizing electrons from measurements on N2 and He we estimated the detection limit in threshold ionization measurements using binary mixtures of CO in N2 to be in the range of several hundreds of ppm. Mass spectra and threshold ionization measurements recorded during catalytic partial oxidation of methane at 1250 °C on a Pt catalyst are presented. The detection of CH3∙ radicals is successfully demonstrated.
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82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
82.30.Cf Atom and radical reactions; chain reactions; molecule-molecule reactions

Efficient stimulated Raman pumping for quantum state resolved surface reactivity measurements

Plinio Maroni, Dimitrios Papageorgopoulos, Amanz Ruf, Rainer D. Beck, and Thomas R. Rizzo

Rev. Sci. Instrum. 77, 054103 (2006); http://dx.doi.org/10.1063/1.2200876 (6 pages) | Cited 6 times

Online Publication Date: 24 May 2006

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We describe the use of stimulated Raman pumping in a molecular beam to perform quantum state resolved gas-surface reactivity measurements for molecules prepared in totally symmetric vibrational states. Vibrational states of homonuclear diatomics as well as totally symmetric vibrations of polyatomic molecules cannot be prepared by direct infrared excitation but are accessible through stimulated Raman pumping by two laser fields when the difference between the incident laser frequencies matches the vibration. We generate a suitable resonant pair of high-energy pump and Stokes laser beams in an injection seeded Raman amplifier filled with the sample gas and equipped with internal gas recirculation. The ability to partially saturate the Raman pumping process in the molecular beam is used to quantify the fraction of vibrationally excited molecules in the irradiated volume, which is needed for quantitative reactivity measurements. We illustrate the method with state resolved reactivity measurements for CH4, prepared in its symmetric C–H stretch vibration on a Ni(100) single crystal surface.
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42.65.Dr Stimulated Raman scattering; CARS
42.65.Es Stimulated Brillouin and Rayleigh scattering
33.80.Be Level crossing and optical pumping
33.15.Mt Rotation, vibration, and vibration-rotation constants
33.80.Rv Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)

High throughput screening of electrocatalysts for fuel cell applications

Mark Prochaska, Jing Jin, Dominic Rochefort, Lin Zhuang, Francis J. DiSalvo, Héctor D. Abruña, and R. B. van Dover

Rev. Sci. Instrum. 77, 054104 (2006); http://dx.doi.org/10.1063/1.2202919 (8 pages) | Cited 13 times

Online Publication Date: 26 May 2006

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We describe methodologies for the generation and screening of combinatorial libraries of electrocatalyst materials for fuel cell applications, generated by cosputtering of three elements onto a Si substrate coated with a Ta adhesion underlayer. Screening was carried out via a fluorescence assay as well as by scanning electrochemical microscopy. Whereas the former provided rapid qualitative screening with limited spatial resolution, the latter provided high spatial resolution. The fluorescence screening method was tested on Pt, PtBi, PtPb, and PtRu nanoparticles, while both methods were tested on a film containing a Pt–Bi–Pb ternary composition spread.
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82.45.Jn Surface structure, reactivity and catalysis
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
82.47.-a Applied electrochemistry
78.55.Hx Other solid inorganic materials
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
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NMR high-resolution magic angle spinning rotor design for quantification of metabolic concentrations

R. Holly, A. Damyanovich, and H. Peemoeller

Rev. Sci. Instrum. 77, 054301 (2006); http://dx.doi.org/10.1063/1.2198728 (4 pages) | Cited 1 time

Online Publication Date: 4 May 2006

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A new high-resolution magic angle spinning nuclear magnetic resonance technique is presented to obtain absolute metabolite concentrations of solutions. The magnetic resonance spectrum of the sample under investigation and an internal reference are acquired simultaneously, ensuring both spectra are obtained under the same experimental conditions. The robustness of the technique is demonstrated using a solution of creatine, and it is shown that the technique can obtain solution concentrations to within 7% or better.
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87.64.K- Spectroscopy
87.14.E- Proteins
87.15.M- Spectra of biomolecules
87.15.N- Properties of solutions of macromolecules
36.20.Kd Electronic structure and spectra
33.25.+k Nuclear resonance and relaxation
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