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Feb 2010

Volume 81, Issue 2, Articles (02xxxx)

Issue Cover Spotlight Figure

Rev. Sci. Instrum. 81, 021301 (2010); http://dx.doi.org/10.1063/1.3314284 (20 pages)

Chanyut Kolitawong, A. Jeffrey Giacomin, and Leann M. Johnson

Whereas many local pressure transducers are commercially available, shear stress transducers are normally custom made. This photograph illustrates a shear stress transducer designed at McGill University for tracking shear stress accurately in time in viscoelastic liquids, including molten plastics such as polyolefins.

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Invited Article: Local shear stress transduction

Chanyut Kolitawong, A. Jeffrey Giacomin, and Leann M. Johnson

Rev. Sci. Instrum. 81, 021301 (2010); http://dx.doi.org/10.1063/1.3314284 (20 pages) | Cited 2 times

Online Publication Date: 24 February 2010

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This is a comprehensive review of local direct measurement shear stress transducers. Transducers are first classified by their movement, measuring mode, and mechanism. These categories are then subclassified into active or passive movement, static or dynamic measuring mode, and rotational or translational mechanisms. Over 80 transducers are reviewed and tabulated. Finally, sources of transducer error are analyzed. Primary sources of error are transducer and housing misalignment, material ingress around the active face, active face roughness, and the effects of temperature gradients when making measurements on surfaces where temperature gradients develop.
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07.07.Mp Transducers
46.80.+j Measurement methods and techniques in continuum mechanics of solids
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back to top Optics; Atoms and Molecules; Spectroscopy; Photon Detectors

Variable-wavelength frequency-domain terahertz ellipsometry

T. Hofmann, C. M. Herzinger, A. Boosalis, T. E. Tiwald, J. A. Woollam, and M. Schubert

Rev. Sci. Instrum. 81, 023101 (2010); http://dx.doi.org/10.1063/1.3297902 (7 pages) | Cited 15 times

Online Publication Date: 2 February 2010

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We report an experimental setup for wavelength-tunable frequency-domain ellipsometric measurements in the terahertz spectral range from 0.2 to 1.5 THz employing a desktop-based backward wave oscillator source. The instrument allows for variable angles of incidence between 30° and 90° and operates in a polarizer-sample-rotating analyzer scheme. The backward wave oscillator source has a tunable base frequency of 107–177 GHz and is augmented with a set of Schottky diode frequency multipliers in order to extend the spectral range to 1.5 THz. We use an odd-bounce image rotation system in combination with a wire grid polarizer to prepare the input polarization state. A highly phosphorous-doped Si substrate serves as a first sample model system. We show that the ellipsometric data obtained with our novel terahertz ellipsometer can be well described within the classical Drude model, which at the same time is in perfect agreement with midinfrared ellipsometry data obtained from the same sample for comparison. The analysis of the terahertz ellipsometric data of a low phosphorous-doped n-type Si substrate demonstrates that ellipsometry in the terahertz spectral range allows the determination of free charge-carrier properties for electron concentrations as low as 8×1014 cm−3.
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07.60.Fs Polarimeters and ellipsometers
84.40.Fe Microwave tubes (e.g., klystrons, magnetrons, traveling-wave, backward-wave tubes, etc.)
42.79.Ci Filters, zone plates, and polarizers

Multifunctional integrating sphere setup for luminous flux measurements of light emitting diodes

Tuomas Poikonen, Pasi Manninen, Petri Kärhä, and Erkki Ikonen

Rev. Sci. Instrum. 81, 023102 (2010); http://dx.doi.org/10.1063/1.3285263 (7 pages)

Online Publication Date: 2 February 2010

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A multifunctional setup based on the absolute integrating sphere method for measuring luminous flux of light emitting diodes (LEDs) is presented. The total luminous flux in 2π and 4π geometries and partial luminous flux with variable cone angle can be measured with the same custom-made integrating sphere. The number and area of ports and baffles of the sphere was minimized. The sphere has three ports: a main port, a detector port, and an auxiliary port, located in the same hemisphere. The other hemisphere is free of ports. The main port is used for the calibration of the sphere as well as for the LED under test. Only one absolute calibration of the integrating sphere photometer is needed for measuring LEDs in all three geometries. The spatial nonuniformity correction is needed only for LEDs with low directivity or having significant minor beams. The expanded uncertainty (k = 2) for the measurement setup varies between 1.2% and 4.6% depending on the measurement geometry, color, and the angular spread of the LED light beam. A complete calibration procedure of the constructed integrating sphere photometer is presented as well as comparison measurements with a goniophotometer.
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85.60.Jb Light-emitting devices
07.60.Dq Photometers, radiometers, and colorimeters

Microfluidic refractometer with integrated optical fibers and end-facet transmission gratings

Lei Lei, Hao Li, Jian Shi, and Yong Chen

Rev. Sci. Instrum. 81, 023103 (2010); http://dx.doi.org/10.1063/1.3280226 (4 pages) | Cited 5 times

Online Publication Date: 2 February 2010

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We demonstrated a microfluidic refractometer with an integrated high resolution transmission grating. This grating was fabricated by UV nanoimprinting on the end facet of a multimode optical fiber which was then placed in the plan of the microfluidic device and perpendicular to a microchannel. On the opposite side of the channel, three cleaved optical fibers were added for the light collection of the zeroth and the ± first diffraction orders. A white light source was used for illumination and the diffraction beams were analyzed with a minispectrometer. The transmission grating was merged in the sample solution of the channel, providing a refractive index-dependent diffraction efficiency. As expected, the diffraction efficiency of the zeroth and the ± first diffraction orders are different, both being reliable for the refractive index monitoring. Such a white source and multibeam diffraction analysis also allows monitoring the sample absorption or fluorescence, thereby providing a more accurate determination of the sample refraction index.
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42.81.-i Fiber optics
42.79.Dj Gratings

Laser-plasma debris from a rotating cryogenic–solid-Xe target

Sho Amano, Yutaka Inaoka, Hiroki Hiraishi, Shuji Miyamoto, and Takayasu Mochizuki

Rev. Sci. Instrum. 81, 023104 (2010); http://dx.doi.org/10.1063/1.3293461 (6 pages) | Cited 3 times

Online Publication Date: 5 February 2010

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We investigate the characteristics of laser plasma debris that is responsible for damaging optics. The debris is composed of fast ions, neutral particles, and fragments, and originates from a solid Xe target on a rotating drum that we developed as an extreme ultraviolet (EUV) source. The ice fragments appear to be a problem most notably with solid Xe targets; however, we find that the damage induced by Xe ice fragments can be avoided by simply reducing the laser pulse energy. We find the number of fast neutral particles to be an order of magnitude less than the number of ions, and we clarify that the plasma debris is primarily composed of fast ions. In addition, we find that the number of fast ions having a few dozen keV of energy decreases when using the rotating target compared with the rest target. We attribute this to a gas curtain effect from the Xe gas localized at the rotating target surface. We estimate the sputtering rate of the Mo/Si mirror, which is caused primarily by the fast ions, to be 104 nm/1×106 shots at 190 mm from the source plasma and at an 11.25° angle from the incident laser beam. Up to the 1×106 shots exposure, remarkable degradation of the mirror reflectivity is not observed though the sputtering damages the mirror. Mitigation of the ions by using gas and/or magnetic fields will further improve the mirror lifetime. By comparing with a liquid jet Xe target, we conclude that the sputtering rate per conversion efficiency when using the solid Xe targets on the rotating drum is the same as that when using the liquid Xe targets. The high conversion efficiency of 0.9% in the rotating drum solid Xe target makes this technique useful for developing laser plasma EUV sources.
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52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
42.79.Bh Lenses, prisms and mirrors
52.50.Dg Plasma sources

X-ray polarimeter with a transmission multilayer

Shunji Kitamoto, Hiroshi Murakami, Youich Shishido, Norimitsu Gotoh, Takuma Shibata, Kousuke Saito, Takeshi Watanabe, Jun’ichi Kanai, Eri Takenaka, Kenta Nagasaki, Masaki Yoshida, Dai Takei, and Mikio Morii

Rev. Sci. Instrum. 81, 023105 (2010); http://dx.doi.org/10.1063/1.3294330 (5 pages) | Cited 1 time

Online Publication Date: 5 February 2010

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We fabricated a novel x-ray polarimeter with a transmission multilayer and measured its performance with synchrotron radiation. A self standing multilayer with seven Mo/Si bilayers was installed with an incident angle of 45° in front of a back-illuminated CCD. The multilayer can be rotated around the normal direction of the CCD keeping an incident angle of 45°. This polarimeter can be easily installed along the optical axis of x-ray optics. By using the CCD as a photon counting detector with a moderate energy resolution, the polarization of photons in a designed energy band can be measured along with the image. At high photon energies, where the multilayer is transparent, the polarimeter can be used for imaging and spectroscopic observations. We confirmed a modulation factor of 45% with 45% and 17% transmission for P- and S-polarization, respectively.
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07.85.-m X- and γ-ray instruments
07.60.Fs Polarimeters and ellipsometers

Improved piezoelectric actuators for use in high-speed pulsed valves

David L. Proctor, Daniel R. Albert, and H. Floyd Davis

Rev. Sci. Instrum. 81, 023106 (2010); http://dx.doi.org/10.1063/1.3309777 (6 pages) | Cited 1 time

Online Publication Date: 16 February 2010

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We describe the assembly of piezoelectric actuators suitable for use in Proch–Trickl pulsed gas valves employed in pulsed molecular beam experiments. In their simplest form, these actuators have performance equal to and resistance to chemical attack far superior to the recently discontinued commercial actuator around which the valve was originally designed. New actuators have been designed employing several different dual piezo configurations. The dual piezo design reliably produces shorter pulses than the original actuator, resulting in reduced gas consumption and lower average source chamber pressures for a given backing pressure and pulse rate. By electrically isolating the actuator assembly, active adjustment of the closed position may be achieved by simple addition of a continuous voltage bias.
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37.20.+j Atomic and molecular beam sources and techniques
85.50.-n Dielectric, ferroelectric, and piezoelectric devices

Production of a coherent pair of light beams with a microwave frequency difference from a single extended-cavity diode laser

Sin Hyuk Yim and D. Cho

Rev. Sci. Instrum. 81, 023107 (2010); http://dx.doi.org/10.1063/1.3309782 (4 pages) | Cited 3 times

Online Publication Date: 19 February 2010

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We produced a pair of coherent laser beams with a 3-GHz frequency difference by optically phase locking two modes from a single, multimode extended-cavity diode laser. This method is complementary to either a direct modulation or an optical phase locking of two independent lasers. A large differential frequency shift between the two modes of the laser allows efficient phase locking. We developed a simple theory to account for the large differential frequency shift. Allan deviation of the beat frequency when the two modes are phase-locked drops as an inverse of the measurement time and it reaches 10−14 when the time is 1 h. Coherent population trapping spectroscopy of Rb atoms using the phase-locked beams resulted in a spectrum as narrow as that of the case using direct modulation by a stable frequency synthesizer.
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42.60.Fc Modulation, tuning, and mode locking
42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.50.Wk Mechanical effects of light on material media, microstructures and particles
42.60.By Design of specific laser systems
back to top Particle Sources, Optics and Acceleration; Particle Detectors

Design and development of a radio frequency quadrupole linac postaccelerator for the Variable Energy Cyclotron Center rare ion beam project

S. Dechoudhury, V. Naik, M. Mondal, A. Chatterjee, H. K. Pandey, T. K. Mandi, A. Bandyopadhyay, P. Karmakar, S. Bhattacharjee, P. S. Chouhan, S. Ali, S. C. L. Srivastava, and A. Chakrabarti

Rev. Sci. Instrum. 81, 023301 (2010); http://dx.doi.org/10.1063/1.3280175 (6 pages) | Cited 4 times

Online Publication Date: 2 February 2010

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A four-rod type heavy-ion radio frequency quadrupole (RFQ) linac has been designed, constructed, and tested for the rare ion beam (RIB) facility project at VECC. Designed for cw operation, this RFQ is the first postaccelerator in the RIB beam line. It will accelerate A/q ≤ 14 heavy ions coming from the ion source to the energy of around 100 keV/u for subsequent acceleration in a number of Interdigital H-Linac. Operating at a resonance frequency of 37.83 MHz, maximum intervane voltage of around 54 kV will be needed to achieve the final energy over a vane length of 3.12 m for a power loss of 35 kW. In the first beam tests, transmission efficiency of about 90% was measured at the QQ focus after the RFQ for O5+ beam. In this article the design of the RFQ including the effect of vane modulation on the rf characteristics and results of beam tests will be presented.
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29.20.Ej Linear accelerators
29.25.Ni Ion sources: positive and negative
41.75.Ak Positive-ion beams
29.27.Eg Beam handling; beam transport
29.27.Bd Beam dynamics; collective effects and instabilities

Electron proportional gas counter for linear and elliptical Mössbauer polarimetry

F. Tanczikó, Sz. Sajti, L. Deák, D. G. Merkel, G. Endrőczi, D. L. Nagy, L. Bottyán, W. Olszewski, and K. Szymański

Rev. Sci. Instrum. 81, 023302 (2010); http://dx.doi.org/10.1063/1.3294425 (8 pages)

Online Publication Date: 2 February 2010

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Design, characterization, and selected applications of a novel electron detector dedicated to conventional perpendicular- and low-angle-incidence conversion electron Mössbauer spectroscopy are presented. The setup is suitable for varying the incident angle and external magnetic fields on Mössbauer source and absorber. Test experiments were performed on α-mathe films using a conventional single-line matho(Rh) and magnetically split, matho(α-Fe) Mössbauer sources. The integral “blackness effect” in conversion-electron Mössbauer spectra of mathe isotope-enriched absorbers is demonstrated and shown to be pronounced at shallow angles of incidence. In order to determine the alignment and sign of the hyperfine field in an isotope-enriched absorber, the blackness effect is accounted for in a semiempirical way by using single-line source/absorber experimental relative intensities determined independently. This method works with high accuracy for linear polarimetry; however it is only a rough approximation in the case of nearly circular polarimetry.
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29.40.Cs Gas-filled counters: ionization chambers, proportional, and avalanche counters

Investigations of the emittance and brightness of ion beams from an electron beam ion source of the Dresden EBIS type

Alexandra Silze, Erik Ritter, Günter Zschornack, Andreas Schwan, and Falk Ullmann

Rev. Sci. Instrum. 81, 023303 (2010); http://dx.doi.org/10.1063/1.3284512 (5 pages) | Cited 5 times

Online Publication Date: 4 February 2010

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We have characterized ion beams extracted from the Dresden EBIS-A, a compact room-temperature electron beam ion source (EBIS) with a permanent magnet system for electron beam compression, using a pepper-pot emittance meter. The EBIS-A is the precursor to the Dresden EBIS-SC in which the permanent magnets have been replaced by superconducting solenoids for the use of the source in high-ion-current applications such as heavy-ion cancer therapy. Beam emittance and brightness values were calculated from data sets acquired for a variety of source parameters, in leaky as well as pulsed ion extraction mode. With box shaped pulses of C4+ ions at an energy of 39 keV root mean square emittances of 1–4 mm mrad and a brightness of 10 nA mm−2 mrad−2 were achieved. The results meet the expectations for high quality ion beams generated by an electron beam ion source.
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29.25.Ni Ion sources: positive and negative
29.25.Bx Electron sources
87.56.-v Radiation therapy equipment
87.53.Jw Therapeutic applications, including brachytherapy

A multichannel time-of-flight system for observation of energetic ions of multispecies generated from relativistic laser plasma

K. Matsukado, M. Fujimoto, H. Takahashi, Y. Kawada, S. Ohsuka, and S. Aoshima

Rev. Sci. Instrum. 81, 023304 (2010); http://dx.doi.org/10.1063/1.3309781 (5 pages)

Online Publication Date: 17 February 2010

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A multichannel time-of-flight (TOF) system was constructed to observe the ions generated from relativistic laser plasma, where the ions have polychromatic energies and multiple species. The TOF system is composed of a ten-channel scintillation detector array and an electromagnet that generates a magnetic field of 0–1.24 T. The magnet field enables us to analyze protons, deuterons, and full-stripped carbon ions to 50, 25, and 150 MeV, respectively. The system experimentally identified protons of 0.27–1.6 MeV energy and ions of a half specific charge (deuterons of 0.3–0.8 MeV and full-stripped carbons of 1.8–4.8 MeV). The measured TOF values agree well with the calculated values within the designed accuracy; ±2.5 ns for protons and ±5 ns for the others (d or C6+) on each detector channel. Comparison of ion numbers detected by a track detector (CR-39) and the TOF system enabled us to obtain the number of ions detected on each scintillation counter with less than 16% error.
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52.70.Ds Electric and magnetic measurements
52.25.Tx Emission, absorption, and scattering of particles
52.27.Ny Relativistic plasmas
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
29.30.Aj Charged-particle spectrometers: electric and magnetic
29.40.Mc Scintillation detectors
back to top Nuclear Physics, Fusion and Plasmas

High speed infrared camera diagnostic for heat flux measurement in NSTX

J.-W. Ahn, R. Maingi, D. Mastrovito, and A. L. Roquemore

Rev. Sci. Instrum. 81, 023501 (2010); http://dx.doi.org/10.1063/1.3297899 (4 pages) | Cited 13 times

Online Publication Date: 3 February 2010

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A new high speed infrared camera has been successfully implemented and produced first set of heat flux measurements on the lower divertor tiles in the NSTX tokamak. High spatial and temporal resolutions, 6.4 mm and 1.6–6.3 kHz, respectively, enable us to investigate detailed structure of heat flux deposition pattern caused by transient events such as edge localized modes. A comparison of the data with a slow infrared camera viewing the same region of interest shows good agreement between the two independent measurements. Data analysis for various plasma conditions is in progress.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.55.Fa Tokamaks, spherical tokamaks

Miniature shock tube for laser driven shocks

Michel Busquet, Patrice Barroso, Thierry Melse, and Daniel Bauduin

Rev. Sci. Instrum. 81, 023502 (2010); http://dx.doi.org/10.1063/1.3301431 (5 pages) | Cited 6 times

Online Publication Date: 12 February 2010

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We describe in this paper the design of a miniature shock tube (smaller than 1 cm3) that can be placed in a vacuum vessel and allows transverse optical probing and longitudinal backside extreme ultraviolet emission spectroscopy in the 100–500 Å range. Typical application is the study of laser launched radiative shocks, in the framework of what is called “laboratory astrophysics.”
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47.40.Nm Shock wave interactions and shock effects
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Straightforward correction for the astigmatism of a Czerny–Turner spectrometer

C. Chrystal, K. H. Burrell, and N. A. Pablant

Rev. Sci. Instrum. 81, 023503 (2010); http://dx.doi.org/10.1063/1.3309792 (5 pages) | Cited 4 times

Online Publication Date: 16 February 2010

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We describe a simple and inexpensive method, which corrects the astigmatism of a Czerny–Turner spectrometer. Initial characterization of the astigmatism for a particular Czerny–Turner spectrometer was performed and the design of the corrective optic is described. The optic is a thin piece of glass, which is used as a one-dimensional waveguide between the light source and the spectrometer such that the sagittal and tangential focal planes are brought to the same position. This method is demonstrated to work well between 360 and 900 nm for an f/4.7 spectrometer. With appropriate materials, corrections for longer and shorter wavelengths should also be possible. When using an inexpensive glass plate, light intensity lost with this method is approximately 12%. Improved surface finish should reduce this loss.
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07.60.Rd Visible and ultraviolet spectrometers
42.79.Gn Optical waveguides and couplers
42.70.Ce Glasses, quartz
42.15.Fr Aberrations
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques

A calorimetric probe for plasma diagnostics

Marc Stahl, Thomas Trottenberg, and Holger Kersten

Rev. Sci. Instrum. 81, 023504 (2010); http://dx.doi.org/10.1063/1.3276707 (4 pages) | Cited 18 times

Online Publication Date: 19 February 2010

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A calorimetric probe for plasma diagnostics is presented, which allows measurements of the power taken by a test substrate. The substrate can be biased and used as an electric probe in order to obtain information about the composition of the total heating power. A new calibration technique for calorimetric probes, which uses monoenergetic electrons at low pressure, has been developed for an improved accuracy. The use of the probe is exemplified with an experiment where both energetic neutral atoms and ions heat the test substrate.
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52.70.-m Plasma diagnostic techniques and instrumentation

A universal support vector machines based method for automatic event location in waveforms and video-movies: Applications to massive nuclear fusion databases

J. Vega, A. Murari, and S. González

Rev. Sci. Instrum. 81, 023505 (2010); http://dx.doi.org/10.1063/1.3302629 (11 pages) | Cited 1 time

Online Publication Date: 19 February 2010

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Big physics experiments can collect terabytes (even petabytes) of data under continuous or long pulse basis. The measurement systems that follow the temporal evolution of physical quantities translate their observations into very large time-series data and video-movies. This article describes a universal and automatic technique to recognize and locate inside waveforms and video-films both signal segments with data of potential interest for specific investigations and singular events. The method is based on regression estimations of the signals using support vector machines. A reduced number of the samples is shown as outliers in the regression process and these samples allow the identification of both special signatures and singular points. Results are given with the database of the JET fusion device: location of sawteeth in soft x-ray signals to automate the plasma incremental diffusivity computation, identification of plasma disruptive behaviors with its automatic time instant determination, and, finally, recognition of potential interesting plasma events from infrared video-movies.
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02.30.-f Function theory, analysis

Simple filtered repetitively pulsed vacuum arc plasma source

Yu. Chekh, I. S. Zhirkov, and M. P. Delplancke-Ogletree

Rev. Sci. Instrum. 81, 023506 (2010); http://dx.doi.org/10.1063/1.3310096 (4 pages)

Online Publication Date: 19 February 2010

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A very simple design of cathodic filtered vacuum arc plasma source is proposed. The source without filter has only four components and none of them require precise machining. The source operates in a repetitively pulsed regime, and for laboratory experiments it can be used without water cooling. Despite the simple construction, the source provides high ion current at the filter outlet reaching 2.5% of 400 A arc current, revealing stable operation in a wide pressure range from high vacuum to oxygen pressure up to more than 10−2 mbar. There is no need in complicated power supply system for this plasma source, only one power supply can be used to ignite the arc, to provide the current for the arc itself, to generate the magnetic field in the filter, and provide its positive electric biasing without any additional high power resistance.
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52.59.Tb Moderate-intensity beams
52.50.Dg Plasma sources
52.25.Fi Transport properties
52.80.Mg Arcs; sparks; lightning; atmospheric electricity

Hydrogen atomic pair-ion production on catalyst surface

W. Oohara and O. Fukumasa

Rev. Sci. Instrum. 81, 023507 (2010); http://dx.doi.org/10.1063/1.3314902 (6 pages) | Cited 3 times

Online Publication Date: 25 February 2010

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To generate a hydrogen pair-ion plasma consisting of only hydrogen atomic pair ions, i.e., H+ and H− ions, the efficient production of pair ions is required. When discharged hydrogen plasma is irradiated to a Ni catalyst, pair ions are produced on the catalyst surface. It is clarified that hydrogen chemisorption on the catalyst affects pair-ion production.
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52.50.Dg Plasma sources
52.25.Jm Ionization of plasmas
52.27.Ep Electron-positron plasmas
52.40.Hf Plasma-material interactions; boundary layer effects
back to top Microscopy and Imaging

A new flexible scatterometer for critical dimension metrology

Matthias Wurm, Frank Pilarski, and Bernd Bodermann

Rev. Sci. Instrum. 81, 023701 (2010); http://dx.doi.org/10.1063/1.3280160 (8 pages) | Cited 4 times

Online Publication Date: 2 February 2010

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At Physikalisch-Technische Bundesanstalt, the National Metrology Institute of Germany, a new type of deep ultraviolet scatterometer has been developed and set up. The concept of the system is very variable and versatile, so that many different types of measurements, e.g., classical scatterometry, ellipsometric scatterometry, polarization-dependent reflectometry, and ellipsometry can be performed. The main application is the characterization of linewidth/critical dimension (CD), grating period (pitch), and edge profile of periodically nanostructured surfaces mainly, but not only, on photomasks. Different operation wavelength between 840 and 193 nm can be used, giving also access to a variety of different at-wavelength metrology connected with state-of-the-art photolithography. It allows to adapt and to vary the measurand and measurement geometry to optimize the sensitivity and the unambiguity for the measurement problem. In this paper the concept, design, and performance of the system is described in detail. First measurement examples are shown and current and future applications are discussed.
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07.60.Hv Refractometers and reflectometers
07.60.Fs Polarimeters and ellipsometers
85.40.Hp Lithography, masks and pattern transfer

Automated coregistered imaging using a hand-held probe-based optical imager

Steven Regalado, Sarah J. Erickson, Banghe Zhu, Jiajia Ge, and Anuradha Godavarty

Rev. Sci. Instrum. 81, 023702 (2010); http://dx.doi.org/10.1063/1.3271019 (10 pages) | Cited 5 times

Online Publication Date: 2 February 2010

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multimedia

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Near-infrared optical imaging holds a promise as a noninvasive technology toward cancer diagnostics and other tissue imaging applications. In recent years, hand-held based imagers are of great interest toward the clinical translation of the technology. However hand-held imagers developed to date are typically designed to obtain surface images and not tomography information due to lack of coregistration facilities. Herein, a recently developed hand-held probe-based optical imager in our Optical Imaging Laboratory has been implemented with novel coregistration facilities toward real-time and tomographic imaging of tissue phantoms. Continuous-wave fluorescence-enhanced optical imaging studies were performed using an intensified charge coupled device camera based imaging system in order to demonstrate the feasibility of automated coregistered imaging of flat phantom surfaces, using a flexible probe that can also contour to curvatures. Three-dimensional fluorescence tomographic reconstructions were also demonstrated using coregistered frequency-domain measurements obtained using the hand-held based optical imager. It was also observed from preliminary studies on cubical phantoms that multiple coregistered scans differentiated deeper targets ( ∼ 3 cm) from artifacts that were not feasible from a single coregistered scan, demonstrating the possibility of improved target depth detectability in the future.
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87.85.Ox Biomedical instrumentation and transducers, including micro-electro-mechanical systems (MEMS)
87.63.L- Visual imaging
42.79.Pw Imaging detectors and sensors
87.19.xj Cancer

A low noise all-fiber interferometer for high resolution frequency modulated atomic force microscopy imaging in liquids

Haider I. Rasool, Paul R. Wilkinson, Adam Z. Stieg, and James K. Gimzewski

Rev. Sci. Instrum. 81, 023703 (2010); http://dx.doi.org/10.1063/1.3297901 (10 pages) | Cited 8 times

Online Publication Date: 2 February 2010

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We have developed a low noise all-fiber interferometer for use as the deflection sensor in liquid environment frequency modulated atomic force microscopy (FM-AFM). A detailed description and rationale for the choice of the critical components are provided along with the design of a simple alignment assembly. The optimization of the deflection sensor toward achieving the highest possible sensitivity and lowest deflection noise density is discussed in the context of an ideal interference cavity. Based on the provided analysis we have achieved deflection noise densities of 2 fm/math on commercially available cantilevers in both ambient and liquid environments. The low noise interferometer works without the need for differential detection, special focusing lenses, or polarization sensitive optics, dramatically simplifying measurements. True atomic resolution imaging of muscovite mica by FM-AFM in water is demonstrated using the developed deflection sensor.
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07.60.Ly Interferometers
07.60.Vg Fiber-optic instruments
42.81.Pa Sensors, gyros
68.37.Ps Atomic force microscopy (AFM)
07.79.Lh Atomic force microscopes

A compact multipurpose nanomanipulator for use inside a scanning electron microscope

E. C. Heeres, A. J. Katan, M. H. van Es, A. F. Beker, M. Hesselberth, D. J. van der Zalm, and T. H. Oosterkamp

Rev. Sci. Instrum. 81, 023704 (2010); http://dx.doi.org/10.1063/1.3271033 (4 pages) | Cited 8 times

Online Publication Date: 5 February 2010

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A compact, two-stage nanomanipulator was designed and built for use inside a scanning electron microscope. It consists of a fine stage employing piezostacks that provide a 15 μm range in three dimensions and a coarse stage based on commercially available stick-slip motors. Besides the fabrication of enhanced probes for scanning probe microscopy and the enhancement of electron field emitters, other novel manipulation processes were developed, such as locating, picking up, and positioning small nanostructures with an accuracy of ∼ 10 nm. In combination with in situ I-V experiments, welding, and etching, this results in a multipurpose nanofactory, enabling a new range of experiments.
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07.78.+s Electron, positron, and ion microscopes; electron diffractometers
07.79.-v Scanning probe microscopes and components
81.16.Ta Atom manipulation

Intermittent contact scanning nonlinear dielectric microscopy

Yoshiomi Hiranaga and Yasuo Cho

Rev. Sci. Instrum. 81, 023705 (2010); http://dx.doi.org/10.1063/1.3274138 (5 pages) | Cited 1 time

Online Publication Date: 8 February 2010

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Intermittent contact scanning nonlinear dielectric microscopy (IC-SNDM) was developed as a novel technique for surface topography measurements and observation of domain structures. Domain structures on ferroelectric single crystals were observed with nanoscale resolution using IC-SNDM. The reproducibility of measurements was improved in comparison to a conventional SNDM operated under contact mode, because the tip and/or sample damage are reduced when using intermittent contact mode. The minimum loading force of the probe to provide basic performance was experimentally determined for IC-SNDM.
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77.80.Dj Domain structure; hysteresis
07.79.-v Scanning probe microscopes and components

Permanent magnet desktop magnetic resonance imaging system with microfabricated multiturn gradient coils for microflow imaging in capillary tubes

Ramin S. Sahebjavaher, Konrad Walus, and Boris Stoeber

Rev. Sci. Instrum. 81, 023706 (2010); http://dx.doi.org/10.1063/1.3280171 (9 pages) | Cited 2 times

Online Publication Date: 11 February 2010

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A prototype for a desktop high-resolution magnetic resonance imaging (MRI) velocimetry instrument to characterize flow fields in a capillary tube is demonstrated. This inexpensive compact system is achieved with a 0.6 T permanent magnetic configuration (Larmor frequency of 25 MHz) and temperature compensation using off-the-shelf NdFeB permanent magnets. A triaxial gradient module with microfabricated copper coils using a lithographic fabrication process has been developed. This gradient module is capable of generating fast-switching gradients (<100 μs) with amplitudes up to 1.7 T/m using custom made current amplifiers, and was optimized for microflow imaging. The radio frequency probe is integrated with the gradient module and is driven by custom electronics. A two-dimensional (2D) cross-sectional static image of the inside of a capillary tube with an inner diameter of 1.67 mm is acquired at an in-plane spatial resolution of better than 40 μm. Time-of-flight flow measurements were also obtained using this MRI system to measure the velocity profile of water flowing at average velocities of above 50 mm/s. The flow profile for slower flow velocities was obtained using phase-encoded techniques, which provides quantitative velocity information in 2D.
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47.85.Np Fluidics
47.55.nb Capillary and thermocapillary flows
47.60.Dx Flows in ducts and channels
47.61.-k Micro- and nano- scale flow phenomena
47.80.Jk Flow visualization and imaging
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