RSI Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue

Dec 1993

Volume 64, Issue 12, pp. 3357-3652

Page 1 of 2 Pages Next Page | Jump to Page

Image and sample geometry effects in SQUID magnetometers

Andrzej Zięba

Rev. Sci. Instrum. 64, 3357 (1993); http://dx.doi.org/10.1063/1.1144306 (19 pages) | Cited 13 times

Full Text: | Download PDF

Show Abstract
This review concerns the interpretation of the signal provided by SQUID magnetometers designed for measurements of magnetization and magnetic susceptibility. ‘‘Image effect’’ refers to the influence of superconducting elements in the vicinity of the sample and detection coil. Several exact and approximate methods are presented for calculation of how the device sensitivity G(r) varies with position r of a unit dipole sample in the presence of a superconducting shielding tube. In particular, the relative decrease of G(r) is approximately given by the third power of the ratio of the detection coil and shield diameters, and the effect of the shield’s finite length is found to be negligible in practical situations. A survey of complex detection coils (Helmholtz, saddle‐type, gradiometer, and second derivative coil) includes calculation of the optimum spacing of the Helmholtz pair in the presence of a superconducting cylinder. The image effects due to the properties of the SQUID circuit and the field‐dependent effects in high‐field SQUID magnetometers are also discussed. Change in the instrument calibration due to sample size, shape, and location is considered for arbitrary samples as well as for specific cases of small, medium, and very long samples. A spherical harmonic expansion of G(r) makes it possible to derive simple formulas describing sample geometry effects for medium‐sized samples with regular geometries (thin rod, cylinder, and rectangular parallelepiped). The results are compared to published experimental data.
Show PACS
85.25.Dq Superconducting quantum interference devices (SQUIDs)
07.55.-w Magnetic instruments and components

Fast‐rise, large‐volume, 1.7‐kG magnetic‐field coil

D. J. Weidman, M. J. Rhee, and R. F. Schneider

Rev. Sci. Instrum. 64, 3376 (1993); http://dx.doi.org/10.1063/1.1144307 (4 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
A one‐turn coil of 20 cm diameter and 30 cm length produces a field up to 1.7 kG with a rise time of 30 ns. The rate of rise of field, nearly 6 T/μs, is faster than for any other coil of this size. Powering the coil is a transformer‐charged pulse‐forming line machine operating at up to 28 kA, 280 kV without deleterious arcing. The field is uniform to 5% over the coil length, focusing an electron beam passing along its axis.
Show PACS
41.85.Lc Particle beam focusing and bending magnets, wiggler magnets, and quadrupoles
07.55.Db Generation of magnetic fields; magnets
85.70.-w Magnetic devices
84.32.Hh Inductors and coils; wiring
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables

Improved multipass optics for diode laser spectroscopy

T. A. Hu, E. L. Chappell, J. T. Munley, and S. W. Sharpe

Rev. Sci. Instrum. 64, 3380 (1993); http://dx.doi.org/10.1063/1.1144308 (4 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Feedback between optical elements can be a major source of noise when trying to attain high sensitivity in infrared absorption experiments. We find that a conventional White‐cell optical arrangement introduces étaloning fringes that modulate the peak‐to‐peak amplitude of our signals by 1 part in 16 666, a fractional change of 6×10−5. Although relatively small, this ‘‘noise’’ is systematic and adds coherently with averaging, obscuring interesting absorption features. An easily constructed multipass optical system suited for performing high‐resolution infrared spectroscopy in molecular beams is described. The design is based on a variation of the White cell and has been optimized for use with lead salt diode lasers. One of the key components in the improved design is the addition of an oscillating mirror for spoiling optical feedback generated by laser scatter and/or poor mode coupling of the laser to the multipass optics.
Show PACS
07.77.-n Atomic, molecular, and charged-particle sources and detectors
37.20.+j Atomic and molecular beam sources and techniques
33.20.Ea Infrared spectra
42.62.Fi Laser spectroscopy
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques

New high‐resolution phonon spectroscopy using impulsive stimulated Brillouin scattering

S. Kinoshita, Y. Shimada, W. Tsurumaki, M. Yamaguchi, and T. Yagi

Rev. Sci. Instrum. 64, 3384 (1993); http://dx.doi.org/10.1063/1.1144309 (10 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
Impulsive stimulated Brillouin scattering is applied to a new high‐resolution phonon spectroscopy, where phonons created by two crossing pump pulses are observed using diffraction of a cw probe light in both time and frequency domains. In time domain, real‐time behavior can be detected sensitively using a digital oscilloscope, while in frequency domain, measurements with high resolution are attainable by means of a spherical Fabry–Perot interferometer. Several examples of the measurements on liquid samples are demonstrated for clarifying various aspects of the phonon generation by the present method: the mechanism of the generation under pulsed light irradiation, the propagation of the generated phonon, the resonance excitation, and the interference with the other nonlinear optical processes. The relation with the ordinary light scattering is also discussed.
Show PACS
42.65.Es Stimulated Brillouin and Rayleigh scattering

Submillisecond response times of oxygen‐quenched luminescent coatings

Alan E. Baron, J. D. S. Danielson, Martin Gouterman, Jiang River Wan, James B. Callis, and Blair McLachlan

Rev. Sci. Instrum. 64, 3394 (1993); http://dx.doi.org/10.1063/1.1144310 (9 pages) | Cited 31 times

Full Text: | Download PDF

Show Abstract
An apparatus and data analysis methodology is described which allows determination of response time to oxygen concentration changes of luminescent oxygen sensor coatings. Utilizing a solenoid valve, a sample chamber creates a pressure jump from 0.1 to 700 Torr in 600 μs that is followed by 15 ms of ringing. An optical detection system measures the response of porphyrin‐based luminescent oxygen sensors to the pressure jump. The pressure in the chamber is measured simultaneously and independently with a piezoresistive pressure transducer. Data analysis techniques using nonlinear least‐squares and numerical convolution of the luminescent response to the pressure rise allow determination of response times of the oxygen sensor. The response to pressure jumps of several luminescent oxygen sensitive coatings designed for video luminescent barometry are measured with this computer‐controlled instrument. Several coatings were studied with response times of ∼2.5 s, ∼400 ms, 11 ms, 1.5 ms, and <25 μs. Studies of the system suggest that we can determine response times down to about 10 μs.
Show PACS
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
78.66.Qn Polymers; organic compounds

Improved recursive convolution integral for the analysis of fluorescence decay data: Local approximation of the apparatus response function by a general polynomial

J. Večeř, A. A. Kowalczyk, and R. E. Dale

Rev. Sci. Instrum. 64, 3403 (1993); http://dx.doi.org/10.1063/1.1144311 (10 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
An analytical solution of the recursion formula for convolution of a sum‐of‐exponentials fluorescence impulse (δ) response with an apparatus response (‘‘lamp’’) function approximated locally by a general polynomial of the nth degree is derived. The five lowest approximations are tested by comparison with properly simulated fluorescence evolution‐and‐decay data. These were obtained by analytical convolution of selected δ responses with an analytically defined apparatus function chosen closely to simulate typically observable flash‐lamp apparatus functions, taking account of the integration within channels inherent in the experimental collection of both ‘‘lamp’’ and fluorescence response curves. A precise comparison of the recovery of various test theoretical mono‐ and sum‐of‐exponentials impulse‐response parameters for the different approximations was attained by performing all calculations for both simulation and nonlinear least‐squares optimization analysis in double precision. The results highlight the advantages of using local higher‐order polynomial approximations under various circumstances. The improved time resolution in particular suggests more expedient regimes of data collection than heretofore possible.
Show PACS
07.05.Bx Computer systems: hardware, operating systems, computer languages, and utilities
87.64.K- Spectroscopy

Reconvolution analysis in time‐resolved fluorescence experiments—an alternative approach: Reference‐to‐excitation‐to‐fluorescence reconvolution

J. Večeř, A. A. Kowalczyk, L. Davenport, and R. E. Dale

Rev. Sci. Instrum. 64, 3413 (1993); http://dx.doi.org/10.1063/1.1144312 (12 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
A novel method for reconstructing the apparatus response function required for accurate detailed analysis of nanosecond time‐resolved fluorescence decay data is proposed and tested with properly constructed simulated data sets for a variety of pertinent cases, using the high‐accuracy convolution algorithm previously developed [J. Večeř, A. A. Kowalczyk, and R. E. Dale, Rev. Sci. Instrum. 64, xxx (1993)]. The veracity of recovery of test mono‐ and multiexponential decay responses by this method, involving the use of two appropriately chosen monoexponential reference decay responses, is shown to be essentially identical to that attainable with the ‘‘true’’ apparatus response function. The method is also demonstrated to exhibit significant advantages in a variety of situations over currently the most widely employed method of overcoming extant problems in the direct determination of an appropriate apparatus function: indirect analysis against a monoexponential reference decay response (δ‐function convolution method, F‐F deconvolution).  
Show PACS
07.05.Bx Computer systems: hardware, operating systems, computer languages, and utilities
87.64.K- Spectroscopy

Spectral resolution of diffuse luminescence by imaging with a position‐sensitive detector through a variable wavelength interference filter

G. David Mendenhall and Ronald H. Fleming

Rev. Sci. Instrum. 64, 3425 (1993); http://dx.doi.org/10.1063/1.1144263 (5 pages)

Full Text: | Download PDF

Show Abstract
The combination of a variable wavelength interference filter and a position‐sensitive photon‐counting detector provide spectra of low‐intensity luminescence. This method has been demonstrated on two luminescent materials, europium (II)‐doped barium fluorobromide [BaFBr/Eu(II)] and uranyl nitrate [UO2(NO3)2⋅6H2O]. Pixel‐by‐pixel division of a luminescence image taken through the filter by an image without the filter corrects for variations in image intensity. The intensity along the long axis of the filter after correction for detector sensitivity constitutes a luminescence emission spectrum. BaFBr/Eu(II) gave delayed emission with a maximum intensity at 395 nm, in reasonable agreement with the measured Eu 5d→4f fluorescence maximum that occurs at 389 nm. The same technique applied to UO2(NO3)2⋅6H2O gave peaks at 511, 539, 567, and ∼600 nm. These did not correspond to experimental fluorescence maxima due to differing self‐absorption effects.
Show PACS
07.60.Rd Visible and ultraviolet spectrometers
78.60.-b Other luminescence and radiative recombination

Optical design considerations and performance of a spectro‐streak apparatus for time‐resolved fluorescence spectroscopy

A. Wiessner and H. Staerk

Rev. Sci. Instrum. 64, 3430 (1993); http://dx.doi.org/10.1063/1.1144264 (10 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
A time‐resolved spectral photometer, i.e., an instrument for simultaneously measuring intensity, time, and wavelength (I‐t‐λ) is described. The ‘‘spectro‐streak’’ apparatus comprises a grating objective coupled to a commercial streak camera with 2‐ps resolution, a channel plate amplifier, a CCD camera, and a computer for data processing. The necessary calibration and correction procedures are discussed in detail; these are sweep nonlinearity correction, shading correction, geometric distortion correction, wavelength calibration, spectral intensity correction, and dispersion correction. The performance of the instrument is demonstrated with an example of current interest, the measurement of the solvatochromic dynamic Stokes shift of fluorescence from a charge‐transfer system in solution.
Show PACS
07.60.Rd Visible and ultraviolet spectrometers
07.68.+m Photography, photographic instruments; xerography
07.60.Dq Photometers, radiometers, and colorimeters
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

Flow cytometer for resolving signals from heterogeneous fluorescence emissions and quantifying lifetime in fluorochrome‐labeled cells/particles by phase‐sensitive detection

John A. Steinkamp, Thomas M. Yoshida, and John C. Martin

Rev. Sci. Instrum. 64, 3440 (1993); http://dx.doi.org/10.1063/1.1144265 (11 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
A phase‐sensitive flow cytometer has been developed that combines flow cytometry and fluorescence lifetime spectroscopy measurement principles to provide unique capabilities for making phase‐resolved measurements on fluorochrome‐labeled cells and particles. Stained cells are analyzed as they intersect a high‐frequency intensity‐modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using only a single‐channel optical detector. The detector output signals, which are phase shifted from a reference signal and amplitude demodulated, are processed by phase‐sensitive detection electronics to resolve signals from heterogeneous fluorescence emissions and quantify single‐component decay times. Results show signal phase shift and amplitude demodulation on fluorospheres; a detection limit threshold of 300–500 fluorescein molecules equivalence for excitation frequencies 1–30 MHz; a measurement precision (coefficient of variation) of 1.8% on alignment fluorospheres and 3.6% on cells stained for DNA content; the resolution of fluorescence signals from cells stained in combination with two fluorochromes, based on differences in their decay times; and the measurement of fluorescence lifetimes directly by the two‐phase ratio method.
Show PACS
87.80.-y Biophysical techniques (research methods)

A complete characterization of x‐ray polarization state by combination of single and multiple Bragg reflections

Qun Shen and K. D. Finkelstein

Rev. Sci. Instrum. 64, 3451 (1993); http://dx.doi.org/10.1063/1.1144266 (5 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
We present a simple method for complete determination of the x‐ray polarization state, using just one Bragg reflection from a single‐crystal analyzer. For the linear polarization components P1 and P2, we show that the usual method of using a 90° Bragg reflection can be extended to using any Bragg reflection with 2θ≠90°. For circular component P3, we use the intensity modulation profile in an azimuthal rotation caused by the phase‐sensitive interference around a multiple‐beam Bragg reflection. The combination of the two measurements allows a straightforward complete determination of x‐ray polarization, including an unpolarized component, in a broad applicable energy range.
Show PACS
41.50.+h X-ray beams and x-ray optics
07.85.-m X- and γ-ray instruments

A computer program to analyze x‐ray diffraction films

Jeffrey H. Nguyen and Raymond Jeanloz

Rev. Sci. Instrum. 64, 3456 (1993); http://dx.doi.org/10.1063/1.1144267 (6 pages) | Cited 20 times

Full Text: | Download PDF

Show Abstract
We have developed a Macintosh computer program to analyze Debye–Scherrer x‐ray powder diffraction films digitized with a conventional scanner. The program uses a fast derivatives‐free procedure to fit distorted ellipses corresponding to the diffraction rings on the film. These ellipses are collapsed into a one‐dimensional plot of intensity versus scattering angle, from which one can extract information about the diffraction pattern that would have been lost in visual reading. Moreover, uncertainties are decreased by a factor of ∼30 over visual reading, and the analysis of diffraction films is reduced to a matter of minutes.
Show PACS
61.05.C- X-ray diffraction and scattering

Production and metrology of 5 μm x‐ray apertures for 100 keV diffraction studies in the diamond anvil cell

Arthur L. Ruoff, Huan Luo, Craig Vanderborgh, Hui Xia, Keith Brister, and Volker Arnold

Rev. Sci. Instrum. 64, 3462 (1993); http://dx.doi.org/10.1063/1.1144268 (5 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
Microminiaturization of the diamond anvil tip is necessary in order to obtain multimegabar pressures. Because of this and the steep pressure gradients present tiny x‐ray beams are required. This paper describes the production and metrology of 5 μm x‐ray apertures for x‐ray diffraction studies to 100 keV in the diamond anvil cell. It is expected that this design will serve as the basis for 2 μm apertures.
Show PACS
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
07.85.-m X- and γ-ray instruments
61.05.cf X-ray scattering (including small-angle scattering)
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.

Gamma‐ray focusing concentrators for astrophysical observations by crystal diffraction in Laue geometry

S. Melone, O. Francescangeli, and R. Caciuffo

Rev. Sci. Instrum. 64, 3467 (1993); http://dx.doi.org/10.1063/1.1144269 (7 pages)

Full Text: | Download PDF

Show Abstract
The diffraction and optical properties of several crystal concentrator configurations which could be adopted in hard x‐ray astrophysical observations are discussed and compared in terms of effective area, focusing characteristics, and overall dimensions. First, a concentrator consisting of a set of circular rings covered with asymmetric mosaic crystals in Laue geometry is considered; focusing is achieved by an appropriate choice of the geometrical parameters and the asymmetry angles. Specific effective areas larger than 600 cm2 can be obtained in the energy range 120–190 keV by using Si (422) Bragg reflections in a device with a diameter of 2.5 m and a focal length of 13.5 m. Afterwards, a spherical‐zone crystal concentrator is analyzed where asymmetric Laue geometry leads to focusing. With a focal length of 8 m and Si (422) reflections, the mean effective area in the energy range 100–300 keV is about 6500 times larger than the focal spot while the separation power of the concentrator is of the order of 10 arcsec. Finally, a concentrator consisting of several coaxial focusing paraboloids is analyzed. The surfaces of the paraboloids are covered by mosaic crystal tiles with lattice planes disposed normally to the meridians. By using Ge crystals with a mosaic width of ≊350 μrad and assuming a focal length f=10 m with a total aperture 2α=16 deg, it is possible to obtain effective areas larger than 1000 cm2 for energies smaller than about 150 keV. On the other hand, the ratio between the mean effective area and the size of the focal spot in the energy range 200–500 keV is higher than 10 000.
Show PACS
95.55.Ka X- and γ-ray telescopes and instrumentation

Adapting a compact Mott spin polarimeter to a large commercial electron energy analyzer for spin‐polarized electron spectroscopy

Di‐Jing Huang, Jae‐Yong Lee, Jih‐Shih Suen, G. A. Mulhollan, A. B. Andrews, and J. L. Erskine

Rev. Sci. Instrum. 64, 3474 (1993); http://dx.doi.org/10.1063/1.1144270 (6 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
A modified Rice University‐type compact Mott spin polarimeter operating at 20 kV is adapted to a large commerical hemispherical electron energy analyzer. Normal energy analyzer functions are preserved via a retractable channeltron in the polarimeter acceleration column. In the spin‐detection mode, the polarimeter permits analysis of two orthogonal transverse spin‐polarization components. Electron trajectory analysis is used to optimize polarimeter lens column voltages in both normal and spin‐detection modes. Performance levels are established by experiments and significantly improved spin‐detection efficiency is shown to be accessible by changes in the polarimeter collection solid angle.
Show PACS
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
61.05.J- Electron diffraction and scattering

Inverse photoemission spectrometer using a BaF2 window for a low‐pass filter

N. Sanada, M. Shimomura, and Y. Fukuda

Rev. Sci. Instrum. 64, 3480 (1993); http://dx.doi.org/10.1063/1.1144271 (2 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
We have built a simple and high performance inverse photoemission spectrometer using a BaF2 window and a Cu–BeO electron multiplier with KBr as the photocathode for low‐ and high‐pass filters, respectively. It is found that using the BaF2 low‐pass filter improves the resolution by 0.2 eV to compare with SrF2. The intensity was reduced to a quarter of that with SrF2, although it is enough to obtain good inverse photoemission spectra.
Show PACS
07.60.Rd Visible and ultraviolet spectrometers
85.60.Gz Photodetectors (including infrared and CCD detectors)
71.20.-b Electron density of states and band structure of crystalline solids

Calibration method for the quantitative analysis of gas mixtures by means of multiphoton ionization mass spectrometry

U. Boesl, C. Weickhardt, S. Schmidt, H. Nagel, and E. W. Schlag

Rev. Sci. Instrum. 64, 3482 (1993); http://dx.doi.org/10.1063/1.1144272 (5 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
A technique for quantitative analysis of gas mixtures in a laser mass spectrometer is presented. It is based on the addition of two calibration gases with different orders of multiphoton ionization process to the sample gas. The ratio of the signals of these two internal standards serves as a sensor for the laser intensity within the ionization volume. Thus strongly fluctuating signals due to higher‐order multiphoton ionization can be normalized for every single laser shot. In addition, for such a relative measurement, effects of long‐term drifts of the apparatus are eliminated. Concentrations varying from a few ppm to several percent could be determined with an accuracy better than 10% at every single laser shot. Therefore this technique allows high time resolution.
Show PACS
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

Ion‐sputtering atomic beam source for high‐resolution laser spectroscopy of refractory elements

M. Wakasugi, W. G. Jin, T. T. Inamura, T. Murayama, T. Wakui, T. Kashiwabara, H. Katsuragawa, T. Ariga, T. Ishizuka, M. Koizumi, and I. Sugai

Rev. Sci. Instrum. 64, 3487 (1993); http://dx.doi.org/10.1063/1.1144457 (5 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
A high‐resolution laser spectroscopy system for refractory elements with an argon‐ion‐ sputtering atomic beam source was constructed, and it has been demonstrated that the sputtering method is extremely useful as an atomic beam source for high‐resolution laser spectroscopy to measure hyperfine structures and isotope shifts for refractory elements, such as Hf, Ta, and W. This source produced intense neutral atomic beams of more than 1010 atoms/s for these elements, and the yield was easily controlled by adjusting the argon‐ion current and the acceleration voltage. Resonance linewidths were 32, 66, and 48 MHz for Hf, Ta, and W, respectively, which are sufficient to measure the hyperfine structures and the isotope shifts in optical transitions. With this system, the signal‐to‐noise ratio reached more than 106. In addition, the temperature of the sputtered atoms found was rather low compared to the kinetic energy given to the atoms.
Show PACS
07.77.-n Atomic, molecular, and charged-particle sources and detectors
37.20.+j Atomic and molecular beam sources and techniques
32.70.Jz Line shapes, widths, and shifts
32.10.Fn Fine and hyperfine structure

Mathematical model for predicting the molecular intensity of a solenoid‐actuated pulsed beam source

B. S. Zou, M. P. Duduković, and P. L. Mills

Rev. Sci. Instrum. 64, 3492 (1993); http://dx.doi.org/10.1063/1.1144273 (7 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
A mathematical model for evaluating the molecular intensity produced by a solenoid‐actuated pulsed beam source is described. The particular source studied here is used to introduce reactant gas pulses at various user‐specified intervals into a fixed‐bed microreactor system for transient catalysis studies where quantification of the inlet pulse intensity is required for data analysis. The model equations which describe the beam source performance utilize relationships from one‐dimensional isentropic gas expansion, gas effusion through a small hole, and macroscopic mass balances around the valve orifice from which a closed‐form algebraic expression for the pulse intensity is obtained. The parameters in this expression represent observables which include the ideal gas specific heat capacity ratio, the stagnation properties of the gas in the supply chamber of the beam source, and the beam valve driver settings. Comparisons between experimental and predicted values for the pulse intensities, where the latter are of the order 1017 molecules per pulse, show excellent agreement.
Show PACS
07.77.-n Atomic, molecular, and charged-particle sources and detectors

Distinction between multicharged ion species with equal q/m

F. Aumayr, H. Kurz, HP. Winter, D. Schneider, M. A. Briere, and J. W. McDonald

Rev. Sci. Instrum. 64, 3499 (1993); http://dx.doi.org/10.1063/1.1144274 (4 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
We present a new technique for selective, highly sensitive, absolute detection of different multiply charged ion species with equal charge‐to‐mass ratios in mixed multicharged ion beams. This is achieved by exploiting the statistics of potential electron emission as induced by the ion beams on a clean metal surface. The applicability of the method is illustrated by way of different practical examples.
Show PACS
41.75.Ak Positive-ion beams
41.75.Cn Negative-ion beams
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Theoretical study of cylindrical energy analyzers for MeV range heavy‐ion beam probes

A. Fujisawa and Y. Hamada

Rev. Sci. Instrum. 64, 3503 (1993); http://dx.doi.org/10.1063/1.1144275 (12 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
A cylindrical energy analyzer with drift spaces is shown to have a second‐order focusing for beam incident angle when the deflection angle is properly chosen. The analyzer has a possibility to be applied to MeV range heavy‐ion beam probes, and will also be available for accurate particle energy measurements in many other fields.
Show PACS
52.70.Nc Particle measurements
41.85.Qg Particle beam analyzers, beam monitors, and Faraday cups
41.75.-i Charged-particle beams

A novel force microscope and point contact probe

S. P. Jarvis, A. Oral, T. P. Weihs, and J. B. Pethica

Rev. Sci. Instrum. 64, 3515 (1993); http://dx.doi.org/10.1063/1.1144276 (6 pages) | Cited 62 times

Full Text: | Download PDF

Show Abstract
The mechanical properties of very small volumes of material can vary greatly from bulk properties. These modified properties are of interest in many areas including the operation of atomic force microscopy (AFM), the study of adhesion and fracture, and the evaluation of electrical contact response. Despite the importance of these properties, AFM has not yet been successfully utilized for their investigation. Most existing AFMs still rely on the control and monitoring of displacements, with forces being inferred from spring constants. This would be fine if other interactions, such as those between the tip and the surface, were minor perturbations. However, this is frequently not the case, particularly for contact mode AFM. Hence very little is known about the forces applied in the contact and their affect on both the tip and the sample. In this article we describe an AFM probe where forces rather than displacements are applied to the tip. This allows absolute determination of contact compliance and hence provides a measure of the tip–surface interaction. As an example of its use we show quantitatively the effect of the adsorbed water and meniscus forces present in ambient probe microscopy.
Show PACS
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy

A bipolar amplifier for controlling piezo translator

Claudio Barchesi, Renato Generosi, and Antonio Cricenti

Rev. Sci. Instrum. 64, 3521 (1993); http://dx.doi.org/10.1063/1.1144472 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
A bipolar amplifier, optimized to control a piezo translator of a scanning tunneling microscope, is described. The apparatus is completely designed using discrete components and it offers a very simple solution to controlling movement of any piezo translator.
Show PACS
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
07.07.Tw Servo and control equipment; robots
85.50.-n Dielectric, ferroelectric, and piezoelectric devices

Ultrahigh vacuum atomic force microscope using a pantograph inchworm mechanism

Sumio Hosaka, Yukio Honda, Tsuyoshi Hasewaga, Tatsuharu Yamamoto, and Masayoshi Kondo

Rev. Sci. Instrum. 64, 3524 (1993); http://dx.doi.org/10.1063/1.1144277 (6 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
An ultrahigh vacuum atomic force microscope (UHV–AFM) with tunneling current detection has been developed. This microscope uses a new type of pantograph inchworm system. The features of the inchworm system are (i) operation of the clamp in normal clamping mode, (ii) an enlargement of the piezo device stroke for clamper stroke, and (iii) compact system for easy use. Our UHV–AFM has (i) six inchworm movements based on the new mechanism, and (ii) a sharp AFM probe whose tip is machined by a focused ion beam fabrication technique. UHV pressure experiments demonstrate that this system provides a contamination‐free surface and can observe atomic resolution AFM images of MoS2 and silicon carbide.
Show PACS
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy
68.35.B- Structure of clean surfaces (and surface reconstruction)

Scanning tunneling microscope data acquisition and control in visual basic

T. L. Porter

Rev. Sci. Instrum. 64, 3530 (1993); http://dx.doi.org/10.1063/1.1144278 (4 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
A general purpose data acquisition and control system for scanning tunneling microscopy (STM) using Visual Basic is presented. This Windows hosted Visual Basic environment is highly desirable for use in STM image manipulation, storage, and printing, but in its standard form is not suitable for most data acquisition and display applications. Many of the inherent limitations in the Visual Basic language have been overcome by the use of direct calls to the Windows Application Program Interface. In this paper, we describe a general Visual Basic STM user interface and control system, and the extensions to the language using the Windows API needed to implement this system.  
Show PACS
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
07.05.Hd Data acquisition: hardware and software
07.05.Kf Data analysis: algorithms and implementation; data management
07.05.Rm Data presentation and visualization: algorithms and implementation
Page 1 of 2 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close