Jump to Content
View Cart
Top 20 Most Read Articles
July 2010
The 20 articles with the most full-text downloads during the month, in descending order.
 |
Inductive conductivity tensor measurement for flowline or material samples Rev. Sci. Instrum. 81, 075102 (2010); http://dx.doi.org/10.1063/1.3449320 (9 pages) Online Publication Date: 2 July 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Present-day galvanic-based electrical conductivity measurements are hampered by limitations and necessary corrections, especially in the domain of geological core analysis. Low-accuracy techniques such as crucible, two-electrode, and four-electrode are constricted by current-path requirements, while high-accuracy techniques are time consuming and have limited domains of applicability. We present a novel apparatus capable of electrical conductivity tensor measurements in a noninvasive, noncontact, inductive manner with resolution from 5 mS/m. Inspired by the triaxial induction logging technology appearing in the oil patch today, our apparatus is naturally applicable in a novel way not only to anisotropic geological core analysis but also to arbitrary material samples and flowline systems.
|
|||
|
Show PACS
|
|||
|
|
WSXM: A software for scanning probe microscopy and a tool for nanotechnology Rev. Sci. Instrum. 78, 013705 (2007); http://dx.doi.org/10.1063/1.2432410 (8 pages) Online Publication Date: 31 January 2007
Full Text:
Read Online (HTML)
|
Download PDF
|
|||
|
Show Abstract
In this work we briefly describe the most relevant features of WSXM, a freeware scanning probe microscopy software based on MS-Windows. The article is structured in three different sections: The introduction is a perspective on the importance of software on scanning probe microscopy. The second section is devoted to describe the general structure of the application; in this section the capabilities of WSXM to read third party files are stressed. Finally, a detailed discussion of some relevant procedures of the software is carried out.
|
||||
|
Show PACS
|
||||
|
|
Multicomponent wavefield characterization with a novel scanning laser interferometer Rev. Sci. Instrum. 81, 073101 (2010); http://dx.doi.org/10.1063/1.3455213 (4 pages) Online Publication Date: 6 July 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
The in-plane component of the wavefield provides valuable information about media properties from seismology to nondestructive testing. A new compact scanning laser ultrasonic interferometer collects light scattered away from the angle of incidence to provide the absolute ultrasonic displacement for both the out-of-plane and an in-plane components. This new system is tested by measuring the radial and vertical polarization of a Rayleigh wave in an aluminum half-space. The estimated amplitude ratio of the horizontal and vertical displacement agrees well with the theoretical value. The phase difference exhibits a small bias between the two components due to a slightly different frequency response between the two processing channels of the prototype electronic circuitry.
|
|||
|
Show PACS
|
|||
|
|
A common-view disciplined oscillator Rev. Sci. Instrum. 81, 055110 (2010); http://dx.doi.org/10.1063/1.3430071 (6 pages) Online Publication Date: 24 May 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
This paper describes a common-view disciplined oscillator (CVDO) that locks to a reference time scale through the use of common-view global positioning system (GPS) satellite measurements. The CVDO employs a proportional-integral-derivative controller that obtains near real-time common-view GPS measurements from the internet and provides steering corrections to a local oscillator. A CVDO can be locked to any time scale that makes real-time common-view data available and can serve as a high-accuracy, self-calibrating frequency and time standard. Measurement results are presented where a CVDO is locked to UTC(NIST), the coordinated universal time scale maintained at the National Institute of Standards and Technology in Boulder, Colorado.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 81, 073704 (2010); http://dx.doi.org/10.1063/1.3458009 (5 pages) Online Publication Date: 14 July 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Frequency-modulation atomic force microscopy (FM-AFM) relies on an accurate tracking of the resonance frequency of a scanning probe. It is now used in environments ranging from ultrahigh vacuum to aqueous solutions, for slow and for fast imaging, with probes resonating from a few kilohertz up to several megahertz. Here we present a versatile experimental setup that detects amplitude, phase, and frequency of AFM probes for resonance frequencies up to 15 MHz and with >70 kHz maximum bandwidth for amplitude/phase detection. We provide generic parameter settings for variable-bandwidth frequency detection and test these using our setup. The signal-to-noise ratio of the frequency detector is sufficiently high to record atomic-resolution images of mica by FM-AFM in aqueous solution.
|
|||
|
Show PACS
|
|||
|
|
Multiple-scanning-probe tunneling microscope with nanoscale positional recognition function Rev. Sci. Instrum. 81, 073706 (2010); http://dx.doi.org/10.1063/1.3456990 (5 pages) Online Publication Date: 15 July 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Over the past decade, multiple-scanning-probe microscope systems with independently controlled probes have been developed for nanoscale electrical measurements. We developed a quadruple-scanning-probe tunneling microscope (QSPTM) that can determine and control the probe position through scanning-probe imaging. The difficulty of operating multiple probes with submicrometer precision drastically increases with the number of probes. To solve problems such as determining the relative positions of the probes and avoiding of contact between the probes, we adopted sample-scanning methods to obtain four images simultaneously and developed an original control system for QSPTM operation with a function of automatic positional recognition. These improvements make the QSPTM a more practical and useful instrument since four images can now be reliably produced, and consequently the positioning of the four probes becomes easier owing to the reduced chance of accidental contact between the probes.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 78, 031101 (2007); http://dx.doi.org/10.1063/1.2709758 (20 pages) Online Publication Date: 30 March 2007
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
The technique of atom probe tomography (APT) is reviewed with an emphasis on illustrating what is possible with the technique both now and in the future. APT delivers the highest spatial resolution (sub-0.3-nm) three-dimensional compositional information of any microscopy technique. Recently, APT has changed dramatically with new hardware configurations that greatly simplify the technique and improve the rate of data acquisition. In addition, new methods have been developed to fabricate suitable specimens from new classes of materials. Applications of APT have expanded from structural metals and alloys to thin multilayer films on planar substrates, dielectric films, semiconducting structures and devices, and ceramic materials. This trend toward a broader range of materials and applications is likely to continue.
|
|||
|
Show PACS
|
|||
|
|
High sensitivity magnetic imaging using an array of spins in diamond Rev. Sci. Instrum. 81, 043705 (2010); http://dx.doi.org/10.1063/1.3385689 (5 pages) Online Publication Date: 23 April 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
We present a solid state magnetic field imaging technique using a two-dimensional array of spins in diamond. The magnetic sensing spin array is made of nitrogen vacancy (NV) centers created at shallow depths. Their optical response is used for measuring external magnetic fields in close proximity. Optically detected magnetic resonance is read out from a 60×60 μm2 field of view in a multiplexed manner using a charge coupled device camera. We experimentally demonstrate full two-dimensional vector imaging of the magnetic field produced by a pair of current carrying microwires. The presented wide-field NV magnetometer offers, in addition to its high magnetic sensitivity and vector reconstruction, an unprecedented spatiotemporal resolution and functionality at room temperature.
|
|||
|
Show PACS
|
|||
|
|
A battery-based, low-noise voltage source Rev. Sci. Instrum. 81, 064706 (2010); http://dx.doi.org/10.1063/1.3455199 (7 pages) Online Publication Date: 30 June 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
A highly stable, low-noise voltage source was designed to improve the stability of the electrode bias voltages of a Penning trap. To avoid excess noise and ground loops, the voltage source is completely independent of the public electric network and uses a 12 V car battery to generate output voltages of ±15 and ±5 V. First, the dc supply voltage is converted into ac-voltage and gets amplified. Afterwards, the signal is rectified, filtered, and regulated to the desired output value. Each channel can deliver up to 1.5 A. The current as well as the battery voltage and the output voltages can be read out via a universal serial bus (USB) connection for monitoring purposes. With the presented design, a relative voltage stability of 7×10−7 over 6.5 h and a noise level equal or smaller than 30 nV/
 is achieved. |
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 81, 063107 (2010); http://dx.doi.org/10.1063/1.3441983 (5 pages) Online Publication Date: 17 June 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
An x-ray spectrometer devoted to dynamical studies of transient systems using the x-ray absorption fine spectroscopy technique is presented in this article. Using an ultrafast laser-induced x-ray source, this optical device based on a set of two potassium acid phthalate conical crystals allows the extraction of x-ray absorption near-edge spectroscopy structures following the Al absorption K edge. The proposed experimental protocol leads to a measurement of the absorption spectra free from any crystal reflectivity defaults and shot-to-shot x-ray spectral fluctuation. According to the detailed analysis of the experimental results, a spectral resolution of 0.7 eV rms and relative fluctuation lower than 1% rms are achieved, demonstrated to be limited by the statistics of photon counting on the x-ray detector.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 75, 2787 (2004); http://dx.doi.org/10.1063/1.1785844 (23 pages) Online Publication Date: 2 September 2004
Full Text:
|
Download PDF
|
||
|
Show Abstract
Since their invention just over 20 years ago, optical traps have emerged as a powerful tool with broad-reaching applications in biology and physics. Capabilities have evolved from simple manipulation to the application of calibrated forces on—and the measurement of nanometer-level displacements of—optically trapped objects. We review progress in the development of optical trapping apparatus, including instrument design considerations, position detection schemes and calibration techniques, with an emphasis on recent advances. We conclude with a brief summary of innovative optical trapping configurations and applications. |
|||
|
Show PACS
|
|||
|
|
Femtosecond pulse shaping using spatial light modulators Rev. Sci. Instrum. 71, 1929 (2000); http://dx.doi.org/10.1063/1.1150614 (32 pages)
Full Text:
|
Download PDF
|
||
|
Show Abstract
We review the field of femtosecond pulse shaping, in which Fourier synthesis methods are used to generate nearly arbitrarily shaped ultrafast optical wave forms according to user specification. An emphasis is placed on programmable pulse shaping methods based on the use of spatial light modulators. After outlining the fundamental principles of pulse shaping, we then present a detailed discussion of pulse shaping using several different types of spatial light modulators. Finally, new research directions in pulse shaping, and applications of pulse shaping to optical communications, biomedical optical imaging, high power laser amplifiers, quantum control, and laser-electron beam interactions are reviewed. © 2000 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
Photoacoustic imaging in biomedicine Rev. Sci. Instrum. 77, 041101 (2006); http://dx.doi.org/10.1063/1.2195024 (22 pages) Online Publication Date: 17 April 2006
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Photoacoustic imaging (also called optoacoustic or thermoacoustic imaging) has the potential to image animal or human organs, such as the breast and the brain, with simultaneous high contrast and high spatial resolution. This article provides an overview of the rapidly expanding field of photoacoustic imaging for biomedical applications. Imaging techniques, including depth profiling in layered media, scanning tomography with focused ultrasonic transducers, image forming with an acoustic lens, and computed tomography with unfocused transducers, are introduced. Special emphasis is placed on computed tomography, including reconstruction algorithms, spatial resolution, and related recent experiments. Promising biomedical applications are discussed throughout the text, including (1) tomographic imaging of the skin and other superficial organs by laser-induced photoacoustic microscopy, which offers the critical advantages, over current high-resolution optical imaging modalities, of deeper imaging depth and higher absorption contrasts, (2) breast cancer detection by near-infrared light or radio-frequency–wave-induced photoacoustic imaging, which has important potential for early detection, and (3) small animal imaging by laser-induced photoacoustic imaging, which measures unique optical absorption contrasts related to important biochemical information and provides better resolution in deep tissues than optical imaging.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 81, 075103 (2010); http://dx.doi.org/10.1063/1.3455217 (16 pages) Online Publication Date: 6 July 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Optical tweezers and atomic force microscope (AFM) cantilevers are often calibrated by fitting their experimental power spectra of Brownian motion. We demonstrate here that if this is done with typical weighted least-squares methods, the result is a bias of relative size between −2/n and +1/n on the value of the fitted diffusion coefficient. Here, n is the number of power spectra averaged over, so typical calibrations contain 10%–20% bias. Both the sign and the size of the bias depend on the weighting scheme applied. Hence, so do length-scale calibrations based on the diffusion coefficient. The fitted value for the characteristic frequency is not affected by this bias. For the AFM then, force measurements are not affected provided an independent length-scale calibration is available. For optical tweezers there is no such luck, since the spring constant is found as the ratio of the characteristic frequency and the diffusion coefficient. We give analytical results for the weight-dependent bias for the wide class of systems whose dynamics is described by a linear (integro)differential equation with additive noise, white or colored. Examples are optical tweezers with hydrodynamic self-interaction and aliasing, calibration of Ornstein–Uhlenbeck models in finance, models for cell migration in biology, etc. Because the bias takes the form of a simple multiplicative factor on the fitted amplitude (e.g. the diffusion coefficient), it is straightforward to remove and the user will need minimal modifications to his or her favorite least-squares fitting programs. Results are demonstrated and illustrated using synthetic data, so we can compare fits with known true values. We also fit some commonly occurring power spectra once-and-for-all in the sense that we give their parameter values and associated error bars as explicit functions of experimental power-spectral values.
|
|||
|
Show PACS
|
|||
|
|
Thermal exchange radius measurement: Application to nanowire thermal imaging Rev. Sci. Instrum. 81, 073701 (2010); http://dx.doi.org/10.1063/1.3455214 (5 pages) Online Publication Date: 2 July 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
In scanning thermal microscopy (SThM) techniques, the thermal exchange radius between tip and sample is a crucial parameter. Indeed, it limits the lateral spatial resolution but, in addition, an accurate value of this parameter is necessary for a precise identification of thermal properties. But until now, the thermal exchange radius is usually estimated but not measured. This paper presents an experimental procedure, based on the 3ω-SThM method, to measure its value. We apply this procedure to evaluate the thermal exchange radius of two commercial probes: the well-known Wollaston one and a new probe constituted of a palladium film on a SiO2 substrate. Finally, presenting silicon nanowire images, we clearly demonstrate that this new probe can reach a spatial resolution better than 100 nm whereas the Wollaston probe hardly reaches a submicronic spatial resolution.
|
|||
|
Show PACS
|
|||
|
|
Invited Article: High-pressure techniques for condensed matter physics at low temperature Rev. Sci. Instrum. 81, 041301 (2010); http://dx.doi.org/10.1063/1.3400212 (8 pages) Online Publication Date: 20 April 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Condensed matter experiments at high pressure accentuate the need for accurate pressure scales over a broad range of temperatures, as well as placing a premium on a homogeneous pressure environment. However, challenges remain in diamond anvil cell technology, including both the quality of various pressure transmitting media and the accuracy of secondary pressure scales at low temperature. We directly calibrate the ruby fluorescence R1 line shift with pressure at T = 4.5 K using high-resolution x-ray powder diffraction measurements of the silver lattice constant and its known equation of state up to P = 16 GPa. Our results reveal a ruby pressure scale at low temperatures that differs by 6% from the best available ruby scale at room T. We also use ruby fluorescence to characterize the pressure inhomogeneity and anisotropy in two representative and commonly used pressure media, helium and methanol:ethanol 4:1, under the same preparation conditions for pressures up to 20 GPa at T = 5 K. Contrary to the accepted wisdom, both media show equal levels of pressure inhomogeneity measured over the same area, with a consistent ΔP/P per unit area of ±1.8 %/(104 μm2) from 0 to 20 GPa. The helium medium shows an essentially constant deviatoric stress of 0.021±0.011 GPa up to 16 GPa, while the methanol:ethanol mixture shows a similar level of anisotropy up to 10 GPa, above which the anisotropy increases. The quality of both pressure media is further examined under the more stringent requirements of single crystal x-ray diffraction at cryogenic temperature. For such experiments we conclude that the ratio of sample-to-pressure chamber volume is a critical parameter in maintaining sample quality at high pressure, and may affect the choice of pressure medium.
|
|||
|
Show PACS
|
|||
|
|
Development of a multiplex fast-scan system for ultrafast time-resolved spectroscopy Rev. Sci. Instrum. 81, 063110 (2010); http://dx.doi.org/10.1063/1.3455809 (10 pages) Online Publication Date: 24 June 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
|||
|
Show Abstract
A fast-scan method was developed to obtain time-resolved signals with femtosecond resolution over a picosecond range on the fly and in real time. Traditional fast-scan methods collect data at each probe wavelength one by one, which is time consuming and thus not possible for the study of photofragile materials. In this work, we have developed a system that performs fast scans with multiplex detection. Ultrafast time-resolved spectroscopy was demonstrated using the newly developed system. Femtosecond laser pulses have been used for pump-probe studies of ultrafast processes in various materials, and both electronic relaxation and vibrational dynamics have been studied. However, experiments have been limited in sensitivity and reliability because they are affected by the long-term instability of the ultrashort laser pulses and by the fragility of the samples. The instability of the sources hinders precise determination of electronic decay dynamics and introduces systematic errors. The fragility of the samples reduces their amount or concentration, and can lead to contamination of the materials even if they were pure before the measurement. These effects make it difficult to obtain reproducible and reliable experimental data. In the present work, we have developed a fast-scan pump-probe spectroscopic system that can complete a set of measurements in less than 2 min. Quantitative estimates of the signal reproducibility demonstrate that these measurements provide higher reproducibility and reliability than conventional measurements.
|
||||
|
Show PACS
|
||||
|
|
Calibration of atomic‐force microscope tips Rev. Sci. Instrum. 64, 1868 (1993); http://dx.doi.org/10.1063/1.1143970 (6 pages)
Full Text:
|
Download PDF
|
||
|
Show Abstract
Images and force measurements taken by an atomic‐force microscope (AFM) depend greatly on the properties of the spring and tip used to probe the sample’s surface. In this article, we describe a simple, nondestructive procedure for measuring the force constant, resonant frequency, and quality factor of an AFM cantilever spring and the effective radius of curvature of an AFM tip. Our procedure uses the AFM itself and does not require additional equipment. |
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 81, 063706 (2010); http://dx.doi.org/10.1063/1.3455219 (8 pages) Online Publication Date: 25 June 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
The quartz tuning fork based probe {e.g.,
Akiyama et al. [Appl. Surf. Sci. 210, 18 (2003)]
}, termed “A-Probe,” is a self-sensing and self-actuating (exciting) probe for dynamic mode atomic force microscope (AFM) operation. It is an oscillatory force sensor consisting of the two discrete resonators. This paper presents the investigations on an improved A-Probe: its batch fabrication and assembly, mounting on an AFM head, electrical setup, characterization, and AFM imaging. The fundamental features of the A-Probe are electrically and optically characterized in “approach-withdraw” experiments. Further investigations include the frequency response of an A-Probe to small mechanical vibrations externally applied to the tip and the effective loading force yielding between the tip and the sample during the periodic contact. Imaging of an electronic chip, a compact disk stamper, carbon nanotubes, and Si beads is demonstrated with this probe at ambient conditions in the so-called frequency modulation mode. A special probe substrate, which can snap on a receptacle fixed on an AFM head, and a special holder including a preamplifier electronic are introduced. We hope that the implementation and characterization of the A-Probe described in this paper will provide hints for new scanning probe techniques.
|
|||
|
Show PACS
|
|||
|
|
Hot nanoindentation in inert environments Rev. Sci. Instrum. 81, 073901 (2010); http://dx.doi.org/10.1063/1.3436633 (13 pages) Online Publication Date: 1 July 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
An instrument capable of performing nanoindentation at temperatures up to 500 °C in inert atmospheres, including partial vacuum and gas near atmospheric pressures, is described. Technical issues associated with the technique (such as drift and noise) and the instrument (such as tip erosion and radiative heating of the transducer) are identified and addressed. Based on these considerations, preferred operation conditions are identified for testing on various materials. As a proof-of-concept demonstration, the hardness and elastic modulus of three materials are measured: fused silica (nonoxidizing), aluminum, and copper (both oxidizing). In all cases, the properties match reasonably well with published data acquired by more conventional test methods.
|
|||
|
Show PACS
|
|||
This Publication
Scitation
Google Scholar
PubMed