Jump to Content
View Cart
Top 20 Most Read Articles
December 2008
The 20 articles with the most full-text downloads during the month, in descending order.
 |
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
|
||||
|
|
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
|
|||
|
|
Rev. Sci. Instrum. 79, 113702 (2008); http://dx.doi.org/10.1063/1.2992483 (7 pages) Online Publication Date: 5 November 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
A software package has been developed to implement the real time feedback control loop needed in scanning probe microscopy on a general purpose desktop computer of the current high-speed/multicore generation. The main features of the implementation of both the feedback loop and the control of the experiment on the same computer are discussed. The package can work with several general purpose data acquisition boards and can be extended in a modular way to further board models; timing performance has been tested with several hardware configurations and some applications common in scanning probe microscopy. The package is available under an Open Source license.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 79, 111301 (2008); http://dx.doi.org/10.1063/1.3005784 (14 pages) Online Publication Date: 20 November 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Destructive analyses of impregnated-cathode assemblies from an ion thruster life test were performed to characterize erosion and degradation after 30 472 h of operation. Post-test inspection of each cathode included examination of the emitter (insert), orifice plate, cathode tube, heater, anode assembly, insulator, and propellant isolator. The discharge-cathode assembly experienced significant erosion due to ion sputtering from the discharge plasma. The keeper electrode plate was removed and the heater and orifice plate were heavily eroded at the conclusion of the test. Had the test continued, these processes would likely have led to cathode failure. The discharge cathode insert experienced significant tungsten transport and temperature dependent barium oxide depletion within the matrix. Using barium depletion semiempirical relations developed by Palluel and Shroff, it is estimated that 25 000 h of operation remained in the discharge insert at the conclusion of the test. In contrast, the neutralizer insert exhibited significantly less tungsten transport and barium oxide depletion consistent with its lower current operation. The neutralizer was estimated to have 140 000 h of insert life remaining at the conclusion of the test. Neither insert had evidence of tungstate or oxide layer formation, previously known to have impeded cathode ignition and operation in similar long duration hollow-cathode tests. The neutralizer cathode was in excellent condition at the conclusion of the test with the exception of keeper tube erosion from direct plume-ion impingement, a previously underappreciated life-limiting mechanism. The most critical finding from the test was a power dependent deposition process within the neutralizer-cathode orifice. The process manifested at low-power operation and led to the production of energetic ions in the neutralizer plume, a potential life-limiting process for the neutralizer. Subsequent return of the engine and neutralizer operation to full-power removed the deposits and energetic ion production ceased.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 79, 114302 (2008); http://dx.doi.org/10.1063/1.3020704 (7 pages) Online Publication Date: 11 November 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
We have developed a portable high power ultrasound system with a very low output impedance amplifier circuit (less than 0.3 Ω) that can transfer more than 90% of the energy from a battery supply to the ultrasound transducer. The system can deliver therapeutic acoustical energy waves at lower voltages than those in conventional ultrasound systems because energy losses owing to a mismatched impedance are eliminated. The system can produce acoustic power outputs over the therapeutic range (greater then 50 W) from a PZT-4, 1.54 MHz, and 0.75 in diameter piezoelectric ceramic. It is lightweight, portable, and powered by a rechargeable battery. The portable therapeutic ultrasound unit has the potential to replace “plug-in” medical systems and rf amplifiers used in research. The system is capable of field service on its internal battery, making it especially useful for military, ambulatory, and remote medical applications.
|
|||
|
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
|
|||
|
|
Methods of single-molecule fluorescence spectroscopy and microscopy Rev. Sci. Instrum. 74, 3597 (2003); http://dx.doi.org/10.1063/1.1589587 (23 pages) Online Publication Date: 23 July 2003
Full Text:
|
Download PDF
|
||
|
Show Abstract
Optical spectroscopy at the ultimate limit of a single molecule has grown over the past dozen years into a powerful technique for exploring the individual nanoscale behavior of molecules in complex local environments. Observing a single molecule removes the usual ensemble average, allowing the exploration of hidden heterogeneity in complex condensed phases as well as direct observation of dynamical state changes arising from photophysics and photochemistry, without synchronization. This article reviews the experimental techniques of single-molecule fluorescence spectroscopy and microscopy with emphasis on studies at room temperature where the same single molecule is studied for an extended period. Key to successful single-molecule detection is the need to optimize signal-to-noise ratio, and the physical parameters affecting both signal and noise are described in detail. Four successful microscopic methods including the wide-field techniques of epifluorescence and total internal reflection, as well as confocal and near-field optical scanning microscopies are described. In order to extract the maximum amount of information from an experiment, a wide array of properties of the emission can be recorded, such as polarization, spectrum, degree of energy transfer, and spatial position. Whatever variable is measured, the time dependence of the parameter can yield information about excited state lifetimes, photochemistry, local environmental fluctuations, enzymatic activity, quantum optics, and many other dynamical effects. Due to the breadth of applications now appearing, single-molecule spectroscopy and microscopy may be viewed as useful new tools for the study of dynamics in complex systems, especially where ensemble averaging or lack of synchronization may obscure the details of the process under study. © 2003 American Institute of Physics. |
|||
|
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
|
|||
|
|
A compact all-fiber displacement interferometer for measuring the foil velocity driven by laser Rev. Sci. Instrum. 79, 113101 (2008); http://dx.doi.org/10.1063/1.3020700 (3 pages) Online Publication Date: 7 November 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
|||
|
Show Abstract
A compact all-fiber displacement interferometer (AFDI) system, working at 1550 nm, has been developed and tested, and its working fundamentals will be introduced in this letter. In contrast with other models of fiber-optic velocity interferometer system, AFDI adopts a single-mode optic fiber pigtail as the detect head, diameter of which is only 1 mm, to collect directly the reflect laser beam from the moving surface, which makes this instrument have some unique advantages in observing the point movements of a small flyer. Preliminary experiments using this instrument to measure the velocity history of a small aluminum thin foil driven by a nanosecond pulse laser were conducted successfully, the precise velocity history profile deduced from the sharp interference fringes and the nanometer resolution in displacement gives an eloquent proof of its eminent abilities. The field depth ( ∼ 2 mm) of our AFDI is a little smaller than the DISAR [
Weng et al., Appl. Phys. Lett. 89, 111101 (2006)
] system, but its compact structure makes it much convenient to operate. Further applications for multipoints velocity history measurements of small targets are under consideration.
|
||||
|
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
|
|||
|
|
Cantilever transducers as a platform for chemical and biological sensors Rev. Sci. Instrum. 75, 2229 (2004); http://dx.doi.org/10.1063/1.1763252 (25 pages) Online Publication Date: 21 June 2004
Full Text:
|
Download PDF
|
||
|
Show Abstract
Since the late 1980s there have been spectacular developments in micromechanical or microelectro-mechanical (MEMS) systems which have enabled the exploration of transduction modes that involve mechanical energy and are based primarily on mechanical phenomena. As a result an innovative family of chemical and biological sensors has emerged. In this article, we discuss sensors with transducers in a form of cantilevers. While MEMS represents a diverse family of designs, devices with simple cantilever configurations are especially attractive as transducers for chemical and biological sensors. The review deals with four important aspects of cantilever transducers: (i) operation principles and models; (ii) microfabrication; (iii) figures of merit; and (iv) applications of cantilever sensors. We also provide a brief analysis of historical predecessors of the modern cantilever sensors. © 2004 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
Time‐of‐Flight Mass Spectrometer with Improved Resolution Rev. Sci. Instrum. 26, 1150 (1955); http://dx.doi.org/10.1063/1.1715212 (8 pages) Online Publication Date: 29 December 2004
Full Text:
|
Download PDF
|
||
|
Show Abstract
A new type of ion gun is described which greatly improves the resolution of a nonmagnetic time‐of‐flight mass spectrometer. The focusing action of this gun is discussed and analyzed mathematically. The validity of the analysis and the practicability of the gun are demonstrated by the spectra obtained. The spectrometer is capable of measuring the relative abundance of adjacent masses well beyond 100 amu. |
|||
|
|
Rev. Sci. Instrum. 79, 113102 (2008); http://dx.doi.org/10.1063/1.3013123 (4 pages) Online Publication Date: 11 November 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Image plates (IPs) are a reusable recording media capable of detecting ionizing radiation, used to diagnose x-ray emission from laser-plasma experiments. Due to their superior performance characteristics in x-ray applications [
C. C. Bradford, W. W. Peppler, and J. T. Dobbins III, Med. Phys. 26, 27 (1999) and
J. Digit. Imaging. 12, 54 (1999)
], the Fuji Biological Analysis System (BAS) IPs are fielded on x-ray diagnostics for the HELEN laser by the Plasma Physics Department at AWE. The sensitivities of the Fuji BAS IPs have been absolutely calibrated for absolute measurements of x-ray intensity in the energy range of 0–100 keV. In addition, the Fuji BAS IP fading as a function of time was investigated. We report on the characterization of three Fuji BAS IP responses to x-rays using a radioactive source, and discrete x-ray line energies generated by the Excalibur soft x-ray facility and the Defense Radiological Standards Centre filter-fluorescer hard x-ray system at AWE.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 79, 113707 (2008); http://dx.doi.org/10.1063/1.3005484 (3 pages) Online Publication Date: 25 November 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
|||
|
Show Abstract
We describe the first lateral junction and fully low voltage scanning tunneling microscope, featuring very high precision, stability, compactness, and image quality (highly oriented pyrolytic graphite atomic resolution images). In its core, the tip and sample each sit on one of two parallel-mounted piezoelectric tube scanners so that the tip-sample gap is regulated along the scanners’ pairing direction. The scanner’s large lateral deflection provides a large gap regulation range even under low voltages, allowing exclusively using only low voltage (less than ±15 V) operational amplifiers to precisely implement the coarse (inertial slider) and fine approach, feedback control, and hence the entire electronics. Because the scanners are identical and adjacent, thermal drifts are minimal.
|
||||
|
Show PACS
|
||||
|
|
On the dynamics of piezoactuated positioning systems Rev. Sci. Instrum. 79, 116101 (2008); http://dx.doi.org/10.1063/1.2982238 (3 pages) Online Publication Date: 5 November 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Piezoelectric actuators (PEAs) are commercially available for producing extremely small displacements. If a PEA is used to drive a positioning mechanism, the combined dynamics is approximated empirically by that of a second-order system. However, the rationale for such an approximation is lacking in the literature, thus leaving some issues unaddressed, such as the scope of and the error associated with the approximation. This paper presents such a rationale for the second-order approximation and a method to quantify the error associated with the approximation, by employing the assumed mode method to solve the governing equation. For the experimental verification, step voltages of 48.2, 64.2, and 75.4 V were used to excite a prototype of the positioning system with a mass ratio of 24.7, 47.7, 87.5, 115.8, and 138.8, respectively; and the measured system step responses were compared to the ones simulated by using the second-order approximation. Also, it is illustrated that the error associated with the approximation can be well characterized and quantified by using the developed method.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 79, 126102 (2008); http://dx.doi.org/10.1063/1.3036985 (2 pages) Online Publication Date: 3 December 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
A circuit capable of measuring nanoampere currents while floating at voltages up to at least 25kV is described. The circuit relays its output to ground potential via an optical fiber. We particularly emphasize the design and construction techniques, which allow robust operation in the presence of high voltage spikes and discharges.
|
|||
|
Show PACS
|
|||
|
|
Calibration of rectangular atomic force microscope cantilevers Rev. Sci. Instrum. 70, 3967 (1999); http://dx.doi.org/10.1063/1.1150021 (3 pages)
Full Text:
|
Download PDF
|
||
|
Show Abstract
A method to determine the spring constant of a rectangular atomic force microscope cantilever is proposed that relies solely on the measurement of the resonant frequency and quality factor of the cantilever in fluid (typically air), and knowledge of its plan view dimensions. This method gives very good accuracy and improves upon the previous formulation by Sader et al. [Rev. Sci. Instrum. 66, 3789 (1995)] which, unlike the present method, requires knowledge of both the cantilever density and thickness. © 1999 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
Cryogenic current-in-plane tunneling apparatus Rev. Sci. Instrum. 79, 123902 (2008); http://dx.doi.org/10.1063/1.2972167 (8 pages) Online Publication Date: 4 December 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
|||||||||
|
Show Abstract
We have designed and fabricated a cryogenic variable-temperature current-in-plane tunneling apparatus to measure the magnetoresistive properties of unpatterned magnetic tunnel junction wafers as a function of temperature. The wafer is mounted on the cold finger of a liquid helium continuous flow cryostat. The temperature can be continuously varied between 7 and 330 K. We describe the design and fabrication of the micromachined silicon probe head that comprises a comb of 20 measuring and 4 leveling probes. The measuring probes are typically 0.7 μm wide and 1.2 μm thick, with lengths of 10, 7, and 4 μm, and a pitch that varies from 1.5 to 30 μm. The leveling probes are used in conjunction with a tilt stage to adjust the parallelism between the comb and the sample wafer during the approach of the probe head. The probe head is mounted on a nonmagnetic x-y stage, which can access a 22×22 mm2 area with a repeatability of ∼ 1 μm. The first measurements taken at room and cryogenic temperatures are shown.
|
||||||||||
|
Show PACS
|
||||||||||
|
|
Surface magneto-optic Kerr effect Rev. Sci. Instrum. 71, 1243 (2000); http://dx.doi.org/10.1063/1.1150496 (13 pages)
Full Text:
|
Download PDF
|
||
|
Show Abstract
The surface magneto-optic Kerr effect (SMOKE) has significantly impacted research on magnetic thin films. This is due to its sensitivity, local probing nature, and experimental simplicity. The polar and longitudinal Kerr effects are characterized by a complex rotation of the plane of polarization of linearly polarized incident light upon reflection from the surface of a ferromagnetic material. The rotation is directly related to the magnetization of the material within the probing region of the light. Light penetrates into metals >20 nm deep, but the SMOKE technique derives its surface sensitivity from the limited thickness of the deposited magnetic film, which can be as thin as one atomic layer. Basic principles, experimental arrangements, and applications of SMOKE are reviewed in order to acquaint the nonspecialist with the technique and place it into perspective. © 2000 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
A positron trap and beam apparatus for atomic and molecular scattering experiments Rev. Sci. Instrum. 79, 113105 (2008); http://dx.doi.org/10.1063/1.3030774 (5 pages) Online Publication Date: 21 November 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
An instrument has been designed and constructed to provide new insights into fundamental, low energy positron scattering processes. The design is based on the Surko trap system and produces a pulsed positron beam with an energy resolution of as good as 54 meV. The design and operation of the apparatus is explained, while the first experimental results from this apparatus have been demonstrated in recent publications.
|
|||
|
Show PACS
|
|||
This Publication
Scitation
Google Scholar
PubMed