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

Flickr Twitter UniPHY Group iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue

Dec 2002

Volume 73, Issue 12, pp. 4057-4404

Page 1 of 2 Pages Next Page | Jump to Page
back to top
RSS Feeds

Inverse problem theory in the optical depth profilometry of thin films

J. F. Power

Rev. Sci. Instrum. 73, 4057 (2002); http://dx.doi.org/10.1063/1.1517054 (85 pages) | Cited 11 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
The problem of nondestructive measurement of composition with depth on the scale of ∼0.1–500 μm, in polymers and related materials, has many applications in traditional and recent areas of thin film processing. This article reviews the optical depth profilometry techniques operating on this scale based on optical absorption, photoluminescence, elastic, and inelastic scattering. These methods include photoacoustic and photothermal imaging (including pulsed laser opto–acoustic profiling), attenuated total reflectance infrared, integrated optical spectroscopy methods (based on excitation of planar waveguide structures), confocal scanning microscopy, and the recent technique of light profile microscopy. The profiling of planar structures is emphasized. A common element of all of these methods is that depth mapping requires the solution of a linear inverse problem, where a map of the sample properties is mathematically reconstructed from a set of experimental measurements. This problem is to some extent ill conditioned in some or all regimes of measurement, with the result that depth maps may show sensitivity to data errors. A method is presented for assessing performance of the above experimental depth profilometry techniques in terms of ill conditioning as indicated by: spatial resolution, sensitivity to data errors, and apparent multiplicity of solutions. This method is applied a priori given a knowledge of the linear response theory and measurement parameters Application is made to individual profiling techniques, the performance of each in applications is reviewed, and an inter-comparison is made based on the conditioning of the inverse problem. © 2002 American Institute of Physics.
Show PACS
82.80.Kq Energy-conversion spectro-analytical methods (e.g., photoacoustic, photothermal, and optogalvanic spectroscopic methods)
01.30.Rr Surveys and tutorial papers; resource letters
02.30.Zz Inverse problems
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
back to top
RSS Feeds
back to top OPTICS; ATOMS and MOLECULES; SPECTROSCOPY; PHOTON DETECTORS

Frequency locking to a high-finesse Fabry–Perot cavity of a frequency doubled Nd:YAG laser used as the optical phase modulator

M. Bregant, G. Cantatore, F. Della Valle, G. Ruoso, and G. Zavattini

Rev. Sci. Instrum. 73, 4142 (2002); http://dx.doi.org/10.1063/1.1519933 (3 pages) | Cited 2 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
We report on the frequency locking of a frequency doubled Nd:YAG laser to a 45 000 finesse, 87-cm-long, Fabry–Perot cavity using a modified form of the Pound–Drever–Hall technique. Necessary signals, such as light phase modulation and frequency correction feedback, are fed directly to the infrared pump laser. This is sufficient to achieve a stable locking of the 532 nm visible beam to the cavity, also showing that the doubling process does not degrade laser performances. © 2002 American Institute of Physics.
Show PACS
42.60.Fc Modulation, tuning, and mode locking
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Rz Doped-insulator lasers and other solid state lasers
42.79.Hp Optical processors, correlators, and modulators
FREE

A compact versatile femtosecond spectrometer

V. Nagarajan, E. Johnson, P. Schellenberg, W. Parson, and R. Windeler

Rev. Sci. Instrum. 73, 4145 (2002); http://dx.doi.org/10.1063/1.1518142 (5 pages) | Cited 14 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A compact apparatus for femtosecond pump–probe experiments is described. The apparatus is based on a cavity-dumped titanium:sapphire laser. Probe pulses are generated by focusing weak (∼1 nJ) pulses into a microstructure fiber that produces broadband continuum pulses with high efficiency. With the pump pulses compressed and probe pulses uncompressed, the rise time of the pump–probe signals is <100 fs. The 830 nm pump pulses are also frequency doubled to generate light for excitation at 415 nm. The versatility of the spectrometer is demonstrated by exciting molecules at either 830 or 415 nm, and probing at wavelengths ranging from 500 to 950 nm. Some results on the green fluorescent protein are presented. © 2002 American Institute of Physics.
Show PACS
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
07.60.Rd Visible and ultraviolet spectrometers
07.57.-c Infrared, submillimeter wave, microwave and radiowave instruments and equipment
07.60.-j Optical instruments and equipment
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Picosecond laser-pump, x-ray probe spectroscopy of GaAs

B. W. Adams, M. F. DeCamp, E. M. Dufresne, and D. A. Reis

Rev. Sci. Instrum. 73, 4150 (2002); http://dx.doi.org/10.1063/1.1516849 (7 pages) | Cited 5 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A laser-pump, x-ray probe spectroscopic experiment is described, and the results are shown. The Ga Kα x-ray fluorescence following x-ray absorption, at the Ga K absorption edge was measured, and its increase due to excitation with subpicosecond pulses of laser light at 4.6 eV photon energy was determined. The x-ray absorption, and thus the fluorescence, is increased for about 200 ps after the laser pulse because additional final states for the x-ray absorption are cleared in the valence band by the laser excitation. The technique could eventually lead to a femtosecond pump-probe spectroscopy with an absolute reference energy level and also to a femtosecond x-ray detector. This is of particular importance to future short-pulse x-ray sources, such as free-electron lasers. © 2002 American Institute of Physics.
Show PACS
78.70.Dm X-ray absorption spectra
78.47.-p Spectroscopy of solid state dynamics
78.70.En X-ray emission spectra and fluorescence

An undulator-based spherical grating monochromator beamline for low energy electron-molecule scattering experiments

Søren V. Hoffmann, Stuart L. Lunt, Nykola C. Jones, David Field, and Jean-Pierre Ziesel

Rev. Sci. Instrum. 73, 4157 (2002); http://dx.doi.org/10.1063/1.1517143 (7 pages) | Cited 17 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A new synchrotron radiation undulator beamline, SGM2, with an energy range of 12–20 eV, has been commissioned on the ASTRID storage ring at the University of Aarhus. Using a spherical grating monochromator, the beamline is presently optimized for an energy of 15.76 eV (78.65 nm), for the 3p5(2P1/2)11s resonance in argon, for use in electron-molecule scattering experiments. Using this beamline in conjunction with an electron-molecule scattering apparatus, a beam of electrons down to kinetic energies of a few meV with a resolution of ∼1 meV full width at half maximum is routinely produced. © 2002 American Institute of Physics.
Show PACS
07.85.Qe Synchrotron radiation instrumentation
07.77.-n Atomic, molecular, and charged-particle sources and detectors
34.80.Bm Elastic scattering
42.79.Dj Gratings

A single-photon detector for the measurement of optical activity in the deep sea

F. Ameli, M. Bonori, C. Coluzza, R. Masullo, M. Petruccetti, F. Massa, and L. Pappalardo

Rev. Sci. Instrum. 73, 4164 (2002); http://dx.doi.org/10.1063/1.1515359 (5 pages) | Cited 3 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A module was constructed for the measurement of deep sea optical activity at a sensitivity level of a single photoelectron. We describe the features of the module and a method for calibrating it. The average sensitivity in the interval from 350 to 500 nm is 0.89 Hz/(photons cm−2 s−1), where Hz is the rate detected by the module. © 2002 American Institute of Physics.
Show PACS
93.85.-q Instruments and techniques for geophysical research: Exploration geophysics
85.60.Gz Photodetectors (including infrared and CCD detectors)
78.20.Ek Optical activity
06.20.F- Units and standards

Operation of a single mode external-cavity laser diode array near 780 nm

S. B. Bayram and T. E. Chupp

Rev. Sci. Instrum. 73, 4169 (2002); http://dx.doi.org/10.1063/1.1516848 (3 pages) | Cited 9 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
We have narrowed the spectral bandwidth of a commercial 2 W laser diode array to be less than 120 MHz near 780 nm. The external-cavity laser diode array system is a standard double-pass Littman–Metcalf configuration operating on a dominant single longitudinal mode. © 2002 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
back to top PARTICLE SOURCES, OPTICS and ACCELERATION; PARTICLE DETECTORS

Role of a metal–dielectric structure for the high-charge-state-ion production in electron cyclotron resonance ion sources

L. Schächter, S. Dobrescu, and K. E. Stiebing

Rev. Sci. Instrum. 73, 4172 (2002); http://dx.doi.org/10.1063/1.1519937 (4 pages) | Cited 4 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
The influence of a metal–dielectric (MD) cylindrical structure, covering the radial walls of the plasma chamber of an electron cyclotron resonance ion source (ECRIS), on the production of highly charged ions is discussed. Its influence on the main plasma parameters (plasma potential, electron density, and electron temperatures) was investigated using the Langmuir probe method. An increase of these parameters was observed when the MD structure was inserted into the plasma chamber of the Frankfurt 14 GHz ECRIS. In addition, the plasma potential was measured independently by determining the offset extraction voltage at zero magnetic field of the magnetic 90° analyzer field with high precision. Good agreement with the Langmuir probe results was obtained. The main influence of the MD structure is characterized by a significant increase of the plasma potential. This indicates that the MD structure helps to increase lifetimes of both, electrons as well as ions. The ion lifetime is known to be one of the essential parameters to influence the production of highly charged ions. © 2002 American Institute of Physics.
Show PACS
52.50.Dg Plasma sources
52.25.-b Plasma properties
52.40.Hf Plasma-material interactions; boundary layer effects
52.70.Ds Electric and magnetic measurements
52.25.Fi Transport properties
52.50.Qt Plasma heating by radio-frequency fields; ICR, ICP, helicons

Characterization of multiterawatt laser-solid interactions for proton acceleration

P. McKenna, K. W. D. Ledingham, I. Spencer, T. McCany, R. P. Singhal, C. Ziener, P. S. Foster, E. J. Divall, C. J. Hooker, D. Neely, A. J. Langley, R. J. Clarke, P. A. Norreys, K. Krushelnick, and E. L. Clark

Rev. Sci. Instrum. 73, 4176 (2002); http://dx.doi.org/10.1063/1.1516855 (9 pages) | Cited 26 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A comprehensive characterization of experimental parameters in a study of proton acceleration by short-pulse laser–solid interactions at intensities up to 1019 W cm−2 is reported. Laser pulse and prepulse conditions were measured, with a contrast ratio of the order of 10−6 obtained. The focused laser intensity was experimentally calibrated using a time-of-flight spectrometer to resolve the stages of ionization of a target gas. By comparing the measured ion yields with predictions of an atomic tunneling ionization model a factor of 1.5 uncertainty in the focused intensity was determined. Drive mechanisms for mounting solid targets with thickness in the range of 0.2 to 125 μm have been developed for use with high-repetition rate lasers. A retro-focus imaging system has also been implemented to position the target relative to the laser focus. The techniques have been applied to study proton acceleration as a function of various laser and target parameters. Measurements of the energy distribution of protons as a function of laser intensity are presented for both mylar and Al targets. A maximum proton energy of 1.5 MeV was observed. A compilation of recent results from a number of laser systems on the conversion efficiency of laser energy to protons is discussed. By comparison, an efficiency of about 0.7% for the present study is encouraging for future tabletop-laser-based ion acceleration. © 2002 American Institute of Physics.
Show PACS
52.38.Kd Laser-plasma acceleration of electrons and ions
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
29.20.-c Accelerators

“Linearizing” an ion cyclotron resonance cell

S. E. Barlow and Mark D. Tinkle

Rev. Sci. Instrum. 73, 4185 (2002); http://dx.doi.org/10.1063/1.1518787 (16 pages) | Cited 13 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
We describe an ion cyclotron resonance (ICR) mass spectrometer that we have built. The design of the instrument was guided in large measure by theoretical consideration; in particular we wished to investigate the effects of improved electrostatic linearity on ICR performance. We found, for instance, that the trap’s performance as a mass spectrometer is essentially independent of the trapping potential. By studying both cyclotron and magnetron modes we were able to characterize both the trap and the magnet. Further, we were able to separate effects of image charge from space charge; this gave us measurements of ion number and ion cloud shape. Finally, we show that the instrument readily provides accurate mass measurements with minimal calibration. © 2002 American Institute of Physics.
Show PACS
07.75.+h Mass spectrometers
06.30.Dr Mass and density

Two-dimensional imaging of neutral alkali atom samples using surface ionization

Katharina Christandl, Gregory P. Lafyatis, Andrei Modoran, and Tung-Hsiu Shih

Rev. Sci. Instrum. 73, 4201 (2002); http://dx.doi.org/10.1063/1.1518149 (5 pages)

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
We describe the design and characterization of a high resolution, high efficiency detector for two-dimensional imaging of neutral atoms. Incident atoms are surface-ionized by a tungsten-coated hot ribbon and the resulting ions are accelerated into a microchannel plate detector with a phosphor screen output. With this design we can detect individual alkali and other low ionization potential atoms and molecules with a spatial resolution of ∼ 20 μm. We find backgrounds on the order of 30 Hz over an active detection region of 20 mm2, a time response of ⩽ 1/30 s, and a detection efficiency of ∼ 50%. This detector can be used to image cold as well as thermal atomic or molecular beams. © 2002 American Institute of Physics.
Show PACS
07.77.-n Atomic, molecular, and charged-particle sources and detectors
42.79.Ls Scanners, image intensifiers, and image converters
85.60.Ha Photomultipliers; phototubes and photocathodes

Application of a time-resolved event counting technique in velocity map imaging

L. Dinu, A. T. J. B. Eppink, F. Rosca-Pruna, H. L. Offerhaus, W. J. van der Zande, and M. J. J. Vrakking

Rev. Sci. Instrum. 73, 4206 (2002); http://dx.doi.org/10.1063/1.1520732 (8 pages) | Cited 20 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
We illustrate the use of a three-dimensional (x,y,t) charge-coupled-device (CCD) camera detection system in an ion imaging experiment. The time measurement is based on the decay characteristics of the phosphor screen, which is recorded in two successive images by a double exposure CCD camera. The strength of the method is illustrated in a velocity map imaging experiment on iodine molecules that are ionized and dissociated by intense femtosecond laser pulses. Singly and doubly charged iodine fragments are detected and their (x,y) coordinates and arrival time are recorded in an event counting routine. We estimate the time resolution of the system to be 1.3 ns. We show that the fragment velocity distribution derived from the (x,y,t) data is similar and in some conditions more accurate than the distribution obtained by a mathematical inversion of the (x,y) data only. This principle of detection can be used in all situations in which inversion methods are impossible, for example, when the particle distribution does not have an axis of symmetry. © 2002 American Institute of Physics.
Show PACS
42.79.Pw Imaging detectors and sensors
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
06.60.Jn High-speed techniques (microsecond to femtosecond)

Crossed-beam two-photon readout system for three-dimensional radiation dosimeters

Joon Myong Song, Brian M. Cullum, Joel Mobley, James S. Bogard, Marko Moscovitch, Gary W. Phillips, and Tuan Vo-Dinh

Rev. Sci. Instrum. 73, 4214 (2002); http://dx.doi.org/10.1063/1.1518789 (4 pages) | Cited 1 time

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
Three-dimensional optical random access memory (3D ORAM) materials with enormous capacity and fast access speed have shown a great potential in overcoming limitations of access and storage capacity in current memory devices. As another useful development of this 3D ORAM, we have shown the application of 3D ORAM materials as a practical dosimeter. The local heating of the polymer matrix by the deposited energy of ionizing radiation is thought to contribute to the conversion of the fluorescent photochromic dye to a nonfluorescent form. The two-photon readout system is very useful in tracking the interactions of energy of ionizing radiation deposited in a polymer matrix. However, the polymer fracturing that has occurred during two-photon readout has been an obstacle in utilization of 3D ORAM materials as a dosimeter. In this work, we further evaluated the readout system using a high-energy variable attenuator in order to prevent polymer fracturing due to the strong absorption of the 1064 nm beam by the polymer matrix. Through adjustment of the 1064 nm beam intensity using this attenuator, two-photon excited fluorescence of anthracene-doped 3D ORAM materials could be obtained without polymer fracturing. As a result of this improved procedure, a highly spatially resolved fluorescence image of anthracene-doped 3D ORAM material could be observed with the two-photon readout system. © 2002 American Institute of Physics.
Show PACS
29.40.-n Radiation detectors
42.70.Jk Polymers and organics
78.55.Kz Solid organic materials
back to top NUCLEAR PHYSICS, FUSION and PLASMAS

Generation and control of field-aligned flow velocity shear in a fully ionized collisionless plasma

T. Kaneko, Y. Odaka, E. Tada, and R. Hatakeyama

Rev. Sci. Instrum. 73, 4218 (2002); http://dx.doi.org/10.1063/1.1518791 (5 pages) | Cited 15 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A modified plasma-synthesis method is developed in order to actively control an ion flow energy along magnetic-field lines, where ion and electron emitters of the same diameter are oppositely set at cylindrical machine ends and the ion emitter is concentrically segmented into three sections. The field-aligned ion flows with radially different energies, or ion flow velocity shears, are generated in a radially uniform plasma potential when each section of the segmented ion emitter is individually biased at a positive value above the plasma potential. © 2002 American Institute of Physics.
Show PACS
52.30.-q Plasma dynamics and flow

Thomson scattering diagnostic of solid density plasmas using x-ray lasers

H. A. Baldis, J. Dunn, M. E. Foord, and W. Rozmus

Rev. Sci. Instrum. 73, 4223 (2002); http://dx.doi.org/10.1063/1.1515386 (6 pages) | Cited 8 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
In this article, we demonstrate through calculations and theoretical analysis the first application of an x-ray laser for probing hot, high-density plasmas (ne ≥ 1023 cm−3) using a Ni-like transient collisional excitation x-ray laser as a probe. Theoretical predictions are used to diagnose the electron temperature in short-pulse (500 fs) laser-produced plasmas. The threshold power of the x-ray probe is estimated by comparing theoretical scattering levels with plasma thermal emission. The necessary spectral resolution of the instrument sufficient for resolving electron temperature is given. Effects of the electron heat flow on the ion-acoustic fluctuation spectra are presented. The outlook for these and next generation experiments are discussed. © 2002 American Institute of Physics.
Show PACS
52.70.La X-ray and γ-ray measurements
42.55.Vc X- and γ-ray lasers
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.65.-y Plasma simulation

Imaging system for low-density plasma by heterodyne interferometer with fan beam microwave

H. Ito, N. Yugami, Y. Nishida, and W. Sakai

Rev. Sci. Instrum. 73, 4229 (2002); http://dx.doi.org/10.1063/1.1516833 (3 pages) | Cited 2 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A microwave imaging system based on a heterodyne interferometer has been developed to measure the spatial distribution of the plasma density without introducing any direct disturbance to the plasma by employing a diode array scattering technique. The imaging system with the use of a fan beam microwave for a radar system demonstrates the principle of the technique by placing finite-size dielectric phantoms instead of the plasma between the horn antenna and the diode antenna array. Experimental results show that very good image of the objects can be reconstructed and the system is equivalent to popularly known multichannel imaging system. As a result, it is possible to make simple, low-cost, and compact microwave interferometer for measuring the spatial distribution of the plasma density. © 2002 American Institute of Physics.
Show PACS
52.70.Gw Radio-frequency and microwave measurements

Probe measurements of ion energy distribution in magnetized plasmas

S. V. Ratynskaia, V. I. Demidov, and K. Rypdal

Rev. Sci. Instrum. 73, 4232 (2002); http://dx.doi.org/10.1063/1.1516854 (5 pages) | Cited 6 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A probe method for measurement of the ion energy distribution in magnetized plasmas is proposed. A cylindrical probe with end plugs is oriented parallel to the magnetic field and used to reduce the electron contribution to the total probe current. The contribution of ions to the second derivative of the total current is identified by experiments with different probe orientation and strength of the magnetic field. The ion density obtained from the measured ion energy distribution is in good agreement with the electron density obtained from measured electron energy distribution. © 2002 American Institute of Physics.
Show PACS
52.70.Ds Electric and magnetic measurements
52.25.Xz Magnetized plasmas

First measurement of neutron emission profile on JT-60U using Stilbene neutron detector with neutron-gamma discrimination

M. Ishikawa, T. Nishitani, A. Morioka, M. Takechi, K. Shinohara, M. Shimada, Y. Miura, M. Nagami, and Yu. A. Kaschuck

Rev. Sci. Instrum. 73, 4237 (2002); http://dx.doi.org/10.1063/1.1518145 (6 pages) | Cited 14 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
This article describes a diagnostic for measuring neutron emission profile in JT-60U. The Stilbene neutron detector, developed by TRINITI laboratory in Russia, has been installed on the JT-60U Tokamak to measure the neutron emission profile for the first time. The Stilbene neutron detector is a detector which combines a Stilbene crystal scintillator with a neutron-gamma pulse shape discrimination circuit, with a very compact size. Performance tests were carried out using neutron and gamma-ray source prior to installation on JT-60U. Good gamma suppression of the Stilbene neutron detector was verified. Though the neutron emission profile obtained by Stilbene neutron detectors has error of 30% in innermost channel with a calculation using measured plasma parameters, there is an agreement within 10% error in the other channels. © 2002 American Institute of Physics.
Show PACS
29.40.Mc Scintillation detectors
28.52.Lf Components and instrumentation
89.30.Jj Nuclear fusion power

Measurements of the nonthermal x-ray emission in the T-10 tokamak using CdTe detectors

P. V. Savrukhin

Rev. Sci. Instrum. 73, 4243 (2002); http://dx.doi.org/10.1063/1.1519938 (3 pages) | Cited 3 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A diagnostic technique based on sets of CdTe detectors is used for measurements of spatial localization and temporal evolution of the nonthermal (Eγ up to 150 keV) x-ray emission in plasma with high density in the T-10 tokamak. Various types of x-ray bursts observed during the density limit disruption appear as a result of the forward bremsstrahlung due to nonthermal electron interaction with the residual plasma as well as to nonuniform interaction of the runaway electrons with the plasma-facing constructions. © 2002 American Institute of Physics.
Show PACS
52.70.La X-ray and γ-ray measurements
52.55.Fa Tokamaks, spherical tokamaks
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.40.Hf Plasma-material interactions; boundary layer effects
07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
back to top MICROSCOPY and IMAGING

Submicrometer-resolution three-dimensional imaging with hard x-ray imaging microtomography

Akihisa Takeuchi, Kentaro Uesugi, Hidekazu Takano, and Yoshio Suzuki

Rev. Sci. Instrum. 73, 4246 (2002); http://dx.doi.org/10.1063/1.1515385 (4 pages) | Cited 13 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
An x-ray microtomography method combined with hard x-ray imaging microscopy was developed that has a potential spatial resolution of the order of 10–100 nm. The system consists of a high-brilliance undulator source of SPring-8, a beam diffuser plate to reduce the coherence of the illumination, a high-precision rotating sample stage, a Fresnel zone plate objective, and a high-resolution x-ray imaging detector. The three-dimensional images of several samples were observed and successfully reconstructed with a pitch pattern of 0.6 μm. © 2002 American Institute of Physics.
Show PACS
07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
42.79.Ci Filters, zone plates, and polarizers

Monolayer topography resolution achieved in a scanning near-field optical microscope

T. Plake, M. Ramsteiner, and H. T. Grahn

Rev. Sci. Instrum. 73, 4250 (2002); http://dx.doi.org/10.1063/1.1519936 (4 pages)

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A low-temperature scanning near-field optical microscope has been adapted to achieve a high topographical sensitivity. This setup allows us to resolve morphological features on semiconductor surfaces of monolayer height, which is demonstrated for two different material systems, monolayer steps on an epitaxial GaN film and growth islands in a GaAs single quantum well (SQW) structure. Complementary photoluminescence measurements for the SQW structure reveal the potential of combining high-resolution topography with spatially resolved optical spectroscopy for investigating semiconductor nanostructures. © 2002 American Institute of Physics.
Show PACS
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
68.37.Uv Near-field scanning microscopy and spectroscopy
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.-a Thin film structure and morphology
68.65.Fg Quantum wells
78.67.De Quantum wells
78.55.Cr III-V semiconductors

Electrochemical preparation of cobalt tips for scanning tunneling microscopy

Cristiano Albonetti, Ilaria Bergenti, Massimiliano Cavallini, Valentin Dediu, Massimiliano Massi, Jean-François Moulin, and Fabio Biscarini

Rev. Sci. Instrum. 73, 4254 (2002); http://dx.doi.org/10.1063/1.1518127 (3 pages) | Cited 8 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
Here we describe a straightforward electrochemical method for fabricating sharp cobalt tips. Such tips are particularly useful for those scanning tunneling microscopy (STM) experiments where the focus is on magnetic properties of the surface and the spin polarized (SP) tunneling current is the relevant property, such as in SPSTM and SP scanning tunneling spectroscopy. © 2002 American Institute of Physics.
Show PACS
07.79.Cz Scanning tunneling microscopes
82.45.-h Electrochemistry and electrophoresis
back to top CONDENSED MATTER; MATERIALS

High-resolution scattering apparatus for surface studies

L. Pedemonte, A. Gussoni, R. Tatarek, and G. Bracco

Rev. Sci. Instrum. 73, 4257 (2002); http://dx.doi.org/10.1063/1.1517147 (7 pages) | Cited 7 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A high-resolution apparatus designed to study the structural and dynamical surface properties is described. The apparatus combines the thermal energy He atom- and the low energy ion-scattering techniques both with time-of-flight detection of the scattered fraction. The energy spread of the supersonic He beam is less than 100 μeV at source temperatures below 35 K. The source temperature can be varied between 22 and 300 K to perform elastic, inelastic, and quasielastic scattering studies over a broad range of incident energies. The scattered beam is detected by a homemade quadrupole mass spectrometer designed to have high efficiency for He. The ion source works between 2 and 5 keV and the ion beam is mass selected by a Wien filter which also separates the transmitted ions from fast neutral species. The beam is detected at a scattering angle of 160° and therefore neutral impact collision ion scattering spectroscopy studies can be performed. The base pressure in the target chamber is in the 10−11 mbar range. The capabilities of the apparatus are tested, and the evolution of surface disorder on Ag(110) up to 800 K is characterized.© 2002 American Institute of Physics.
Show PACS
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.49.Sf Ion scattering from surfaces (charge transfer, sputtering, SIMS)
68.49.Bc Atom scattering from surfaces (diffraction and energy transfer)

Surface domain imaging in external magnetic fields

G. Steierl, G. Liu, D. Iorgov, and J. Kirschner

Rev. Sci. Instrum. 73, 4264 (2002); http://dx.doi.org/10.1063/1.1520729 (6 pages) | Cited 2 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
We report on experimental advances in scanning electron microscopy with polarization analysis that allow the observation of ferromagnetic domains in external magnetic fields of about 0.1 T. This is achieved by using a modified electron optics that produces a magnetic field at the sample surface that is spatially confined on the length scale of 0.1 mm. During imaging, primary and secondary electrons pass through the magnetic field without significant disturbance. We demonstrate that the primary electron beam may be used to keep track of the generated magnetic field. As an exemplary application, the switching processes of rectangular Permalloy elements are analyzed. © 2002 American Institute of Physics.
Show PACS
75.70.Rf Surface magnetism
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
75.60.Ch Domain walls and domain structure

A uniaxial tensile stress apparatus for temperature-dependent magnetotransport and optical studies of thin films

A. C. H. Rowe, K. Fasanella, D. R. Hines, T. Zhou, and S. A. Solin

Rev. Sci. Instrum. 73, 4270 (2002); http://dx.doi.org/10.1063/1.1516852 (7 pages) | Cited 3 times

Online Publication Date: 21 November 2002

Full Text: | Download PDF

Show Abstract
A mechanical apparatus for the application of variable uniaxial tensile stress to thin films grown on bulk material has been designed for use in measuring the electrical and/or optical properties of a thin layer over a temperature range 4.2 K<T<300 K, and in magnetic fields up to 7 T. The induced strain is measured with a resolution of 0.0015% by monitoring the position of a laser beam reflected off the surface of the strained sample. The use of the apparatus is demonstrated on n-type InSb layers grown on GaAs where the uniaxial tensile stress is applied in the [001] direction. At 300 K and strains of up to 0.05%, an increase in the conductivity of approximately 3.5% is observed, most of which (∼2.5%) is the result of an increase in the carrier concentration. The remaining 1% is due to an increase in the carrier mobility. Using band-structure k⋅p theory and the deformation potential parameters obtained from optical spectroscopy measurements under uniaxial compression, these observations are shown to be well described by a reduction in both the fundamental band gap and the carrier effective mass with increasing tensile strain. © 2002 American Institute of Physics.
Show PACS
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
73.61.Ey III-V semiconductors
78.66.Fd III-V semiconductors
07.10.Pz Instruments for strain, force, and torque
78.20.hb Piezo-optical, elasto-optical, acousto-optical, and photoelastic effects
71.20.Nr Semiconductor compounds
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
Page 1 of 2 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. Mathematical analysis of coaxial disk cellular shear loading devices
  2. Femtosecond pulse shaping using spatial light modulators
  3. Calibration of rectangular atomic force microscope cantilevers
  4. Advances in the transient dc photocurrent technique for excited state dipole moment measurements
  5. The development of an electron cyclotron resonance ion source for the heavy ion research facility in Lanzhou
Go to AIP Home
Copyright © American Institute of Physics
close