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Dec 1988

Volume 59, Issue 12, pp. 2535-2629


Cryogenic bathysphere for rapid variable‐temperature characterization of high‐Tc superconductors

John Moreland, Y. Li, R. Folsom, and T. E. Capobianco

Rev. Sci. Instrum. 59, 2535 (1988); http://dx.doi.org/10.1063/1.1139893 (4 pages) | Cited 2 times

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A bathysphere consisting of an inverted Dewar flask for submersible operation in cryogenic fluids is used to measure the resistance of superconductors, including high‐Tc superconducting copper oxides, as a function of temperature from 4 to 300 K. We describe the cryostat incorporating the bathysphere and present data on NbTi (44% Ti) and YBa2Cu3O7−δ with respective superconducting transitions temperatures of 9.5 and 91.5 K. There are several advantages of the bathysphere method. The cryostat is of simple, compact design easily adapted to high‐field applications where magnet bore size is a limiting factor. The sample and thermometer are thermolyzed in the dry vapor trapped at the top of the bathysphere. Temperature can be varied rapidly from 300 to 4 K at a rate of 1 K min with less than a 0.1 K thermal lag between the sample and thermometer.
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07.50.-e Electrical and electronic instruments and components
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment
06.60.Ei Sample preparation (including design of sample holders)

New densimeter for cryogenic fluids by magnetic levitation of a high‐Tc superconductor

K. Fujii, M. Takenaka, and K. Nara

Rev. Sci. Instrum. 59, 2539 (1988); http://dx.doi.org/10.1063/1.1139894 (5 pages) | Cited 8 times

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A new magnetic densimeter for cryogenic fluids has been developed by adapting a magnetic levitation of a high‐Tc superconductor. In this instrument, a superconducting material made of Y–Ba–Cu–O is sealed in a hollow glass buoy, and a stable levitation of the buoy is carried out with the Meissner effect of the superconductor simply by placing the buoy in the fluid above a ring‐shaped permanent magnet. The fluid density is obtained from the magnetic force required to levitate the buoy in the fluid. To measure this force, the magnet is suspended from an electronic balance and the reaction force acting on the magnet is determined directly as a change of the apparent weight of the magnet. Details are given of the theoretical calculation of the force acting on the superconductor in the magnetic field and of the construction of the apparatus. The measurements of the saturated liquid density of nitrogen have shown a standard deviation of 0.014%. The total uncertainty of the measurements is estimated to be less than 0.06%. The results agree with reliable literature values within the experimental uncertainty.
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07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment
62.10.+s Mechanical properties of liquids
06.30.Dr Mass and density
07.55.Db Generation of magnetic fields; magnets
85.70.-w Magnetic devices

Cavity ring‐down optical spectrometer for absorption measurements using pulsed laser sources

Anthony O’Keefe and David A. G. Deacon

Rev. Sci. Instrum. 59, 2544 (1988); http://dx.doi.org/10.1063/1.1139895 (8 pages) | Cited 503 times

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We have developed a technique which allows optical absorption measurements to be made using a pulsed light source and offers a sensitivity significantly greater than that attained using stabilized continuous light sources. The technique is based upon the measurement of the rate of absorption rather than the magnitude of absorption of a light pulse confined within a closed optical cavity. The decay of the light intensity within the cavity is a simple exponential with loss components due to mirror loss, broadband scatter (Rayleigh, Mie), and molecular absorption. Narrowband absorption spectra are recorded by scanning the output of a pulsed laser (which is injected into the optical cavity) through an absorption resonance. We have demonstrated the sensitivity of this technique by measuring several bands in the very weak forbidden b1Σg−X3Σg transition in gaseous molecular oxygen. Absorption signals of less than 1 part in 106 can be detected.
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07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
07.60.Rd Visible and ultraviolet spectrometers
06.60.Ei Sample preparation (including design of sample holders)
42.72.-g Optical sources and standards
07.77.-n Atomic, molecular, and charged-particle sources and detectors
37.20.+j Atomic and molecular beam sources and techniques

Longitudinal discharge N2 laser with automatic preionization using an LC inversion circuit

H. Furuhashi and T. Goto

Rev. Sci. Instrum. 59, 2552 (1988); http://dx.doi.org/10.1063/1.1139896 (5 pages) | Cited 2 times

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A four‐segmented longitudinal discharge low pressure N2 laser (337 nm) is reported in which automatic spark preionization and an LC inversion‐charge transfer excitation circuit are employed. Its laser output power was nearly doubled when the techniques developed here were used. The characteristics of the peak laser output powers are interpreted qualitatively, with the electron densities calculated from the observed discharge voltages and currents.
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42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Lt Gas lasers including excimer and metal-vapor lasers

Performance of a microscopic imaging ellipsometer

D. Beaglehole

Rev. Sci. Instrum. 59, 2557 (1988); http://dx.doi.org/10.1063/1.1139897 (3 pages) | Cited 36 times

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A microscopic imaging ellipsometer has been constructed based on use of a CCD camera and framegrabber board in a PC computer. The performance (sensitivity and speed) are described.
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07.60.Fs Polarimeters and ellipsometers
42.15.Eq Optical system design
42.87.-d Optical testing techniques
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
07.05.Bx Computer systems: hardware, operating systems, computer languages, and utilities

Versatile apparatus for low‐energy and hyperthermal energy ion scattering spectroscopies

R. L. McEachern, D. L. Adler, D. M. Goodstein, G. A. Kimmel, B. R. Litt, D. R. Peale, and B. H. Cooper

Rev. Sci. Instrum. 59, 2560 (1988); http://dx.doi.org/10.1063/1.1139898 (8 pages) | Cited 26 times

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We have designed and constructed an apparatus that combines hyperthermal energy ion scattering (<100 eV) with low‐energy ion scattering (a few hundred eV to several keV). The UHV scattering chamber possesses a full range of sample preparation and characterization capabilities, including LEED, Auger spectroscopy, a Kelvin probe for work function measurements, and facilities for gas or alkali‐metal deposition. The differentially pumped beamline provides well‐collimated, monoenergetic beams of gas or alkali‐metal ions ranging in energy from <10 eV to 10 keV. To illustrate the qualitative changes in the scattering behavior observed over this range, we present experimental results for Na+ scattered off the Cu(110) surface with the incident ion energy ranging from 56 eV to 4 keV. We also show a comparison between 1 keV K+ and 1 keV Ar+ scattered from the same surface.
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07.78.+s Electron, positron, and ion microscopes; electron diffractometers
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

X‐ray diffractometer stage for in situ structural analysis of thin films

R. W. Johnson and W. L. Johnson

Rev. Sci. Instrum. 59, 2568 (1988); http://dx.doi.org/10.1063/1.1139899 (5 pages) | Cited 2 times

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A theta‐two theta x‐ray diffractometer stage has been developed for in situ structural characterization of thin‐film samples. This stage integrates an ultrahigh vacuum dc ion‐beam thin‐film sample preparation chamber with the Siemens D500 x‐ray diffractometer. In vacuo sample translation and manipulation is provided. The stage incorporates resistive heating to 900 K and liquid nitrogen cooling to 150 K. The sample theta rotation is transmitted into the vacuum chamber by a rotary feedthrough. X rays enter the vacuum chamber through a beryllium window with allowed reflection angles from 0 to +168° two‐theta.
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61.05.C- X-ray diffraction and scattering
07.10.-h Mechanical instruments and equipment
06.60.Ei Sample preparation (including design of sample holders)

Personal computer based Fourier transform ion cyclotron resonance mass spectrometer

Shenheng Guan and Patrick R. Jones

Rev. Sci. Instrum. 59, 2573 (1988); http://dx.doi.org/10.1063/1.1139900 (4 pages) | Cited 3 times

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An IBM PC AT compatible computer is used to host the interface of a Fourier transform ion cyclotron resonance mass spectrometer or FTMS. A common fast memory bank for both ion‐excitation waveform and data acquisition is reserved in the computer’s system memory space. All the digital electronics circuitry is assembled on an IBM PC AT extension board. Neither an external frequency synthesizer nor a waveform digitizer is needed. Ion‐excitation waveforms can be generated in either frequency‐sweeping or inverse‐Fourier transform modes. Both excitation and data acquisition can be carried out at eight megawords per second.
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07.75.+h Mass spectrometers
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

Broadband microwave absorption spectrometer for liquid media

Pritish Mukherjee, Timothy R. Gosnell, and Irving J. Bigio

Rev. Sci. Instrum. 59, 2577 (1988); http://dx.doi.org/10.1063/1.1139901 (6 pages) | Cited 1 time

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A broadband, continuous‐sweep microwave spectrometer has been constructed for measurements of the absorption coefficient of aqueous solutions and other liquid media. The spectrometer makes use of the phase fluctuation optical heterodyne technique, which provides a direct measure of the microwave power deposited in the sample. Consequently, in contrast to the standard dielectrometric techniques that indirectly determine the absorption coefficient via separate measurements of the real and imaginary parts of the dielectric constant, this spectrometer directly measures the microwave absorption coefficient. Broadband spectra are obtained using a transmission line to couple microwave power into the liquid sample. The absorption spectrum for deionized water in the range 3–20 GHz is presented as an example and shows excellent agreement with calculated values of the absorption coefficient based on previously published dielectric data.
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07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
07.60.Rd Visible and ultraviolet spectrometers
78.70.Gq Microwave and radio-frequency interactions
78.47.-p Spectroscopy of solid state dynamics

Study of pressure distributions in a megabar diamond indentor cell

Hector E. Lorenzana, H. Boppart, and Isaac F. Silvera

Rev. Sci. Instrum. 59, 2583 (1988); http://dx.doi.org/10.1063/1.1139902 (9 pages) | Cited 7 times

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We have studied pressure distributions and area of contact as a function of load in a diamond indentor cell consisting of a flat diamond plate and diamond indentors of two different radii of curvature. The measurements were conducted with type Ia, IIa, and uncharacterized diamonds. Samples investigated were either ruby or ruby on a tantalum foil. In both cases, the ruby fluorescence was used to determine the pressure distributions. Previous suggestions that the elastic Hertzian solutions are applicable for plastic samples are not supported by these data. We conclude with comments on the prospects of the system for experimental high‐pressure research.
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07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells

Diamond anvil cell and loading system for liquid CO2

Michael Baggen, Ron Manuputy, Ruud Scheltema, and Ad Lagendijk

Rev. Sci. Instrum. 59, 2592 (1988); http://dx.doi.org/10.1063/1.1139903 (4 pages) | Cited 7 times

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A diamond anvil cell designed for optical experiments at low temperatures is described. The design is focused on alignment stability and accurate pressure adjustment. To fill the cell with liquid CO2 a special technique is employed, combining features from high‐pressure and cryogenic‐loading procedures. The method has a short cycle time and does not require the use of gas compressors.
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07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment

Heated cell for electron beam pumped VUV experiments

T. Petersen, P. Millar, L. Frey, F. K. Tittel, W. L. Wilson, R. Sauerbrey, and P. J. Wisoff

Rev. Sci. Instrum. 59, 2596 (1988); http://dx.doi.org/10.1063/1.1139904 (4 pages) | Cited 2 times

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The design of a high‐temperature cell appropriate for electron beam pumping of species emitting in the vacuum ultraviolet is described. The apparatus is capable of maintaining a temperature as high as 750 °C at a cell pressure of up to 6 atm which is suitable for a variety of investigations of atomic and molecular vapors, such as alkali metals and alkali‐metal, rare‐gas mixtures. The performance of this apparatus with rubidium vapor in a buffer gas is described.
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07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
06.60.Ei Sample preparation (including design of sample holders)
07.20.Ka High-temperature instrumentation; pyrometers
42.72.-g Optical sources and standards

Ceramic probe for measuring the thermal conductivity of an electrically conductive liquid by the transient hot wire method

Shin Nakamura, Taketoshi Hibiya, and Fumio Yamamoto

Rev. Sci. Instrum. 59, 2600 (1988); http://dx.doi.org/10.1063/1.1139905 (4 pages) | Cited 12 times

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A new ceramic probe has been developed for measuring the thermal conductivity of an electrically conductive liquid by using the transient hot wire method. A wire was fabricated on a 10‐mm‐thick alumina substrate using a co‐firing technique. To avoid leakage of the current to the liquid, the metallized wire was insulated with a 60‐μm‐thick alumina layer. Also developed for this probe is a method of compensating for the measurement error caused by increases in the resistance of metallized electrodes. The thermal conductivity of mercury was measured with this probe at temperatures of 300–382 K.
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07.50.-e Electrical and electronic instruments and components
07.20.-n Thermal instruments and apparatus
65.20.-w Thermal properties of liquids
65.40.gd Entropy

Techniques for measuring small changes in the orientation of the easy axis in permalloy films

Kees J. Eijkel, Poul de Haan, and René M. de Ridder

Rev. Sci. Instrum. 59, 2604 (1988); http://dx.doi.org/10.1063/1.1139906 (5 pages)

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It is well known that the orientation of the easy axis in permalloy can be affected by annealing. The need in our research for detailed information of the behavior of the easy‐axis orientation in the temperature range from room temperature to 100 °C and the absence of measurement techniques to derive this information, led to the development of two new measurement techniques: (1) an adapted version of the Crowther method for measuring dispersion in easy‐axis orientation combined with the optical Kerr technique and (2) a new measurement technique for determining the orientation of the easy axis combined with a galvanomagnetic method for determining magnetization direction. Both methods give detailed information on the behavior of the easy‐axis orientation as a function of temperature. The resolution of both methods is 0.01° and may be increased, especially for the optical method. The optical method imposes few restrictions on film geometry and may be used, e.g., during a fabrication process. The easy‐axis behavior can be observed locally. The galvanomagnetic technique requires four electrical contacts on the film. The easy‐axis behavior is averaged over the total current‐carrying area. This method can be used for observing the behavior of the easy axis in encapsulated devices.
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75.70.-i Magnetic properties of thin films, surfaces, and interfaces
78.20.Ls Magneto-optical effects
07.55.-w Magnetic instruments and components
81.40.Rs Electrical and magnetic properties related to treatment conditions

Novel automated micro batch analyzer

Jamal A. Sweileh, Jorge L. Lopez, and Purnendu K. Dasgupta

Rev. Sci. Instrum. 59, 2609 (1988); http://dx.doi.org/10.1063/1.1139907 (7 pages) | Cited 2 times

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An automated micro batch analyzer (AMBA) system is described. The sample is introduced into an air‐tight reaction chamber (a polypropylene microcentrifuge tube) by a loop injector made from two three‐way valves by flowing gas. Reagents/diluents are introduced into the chamber from pneumatically pressurized reservoirs provided with on‐off valves. A microprocessor‐controlled timer controls valve status and thus provides control of delivered volumes. Gas bubbles are introduced through the bottom of the chamber to perform mixing; the mixed liquid is then discharged into an optical detector via a bubble gate by superincumbent pressure. The bubble gate allows the data‐acquisition system to collect data only when liquid is actually in the detection cell. For simple fast reactions, throughput rates of 210 samples/h could be obtained.
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82.80.Kq Energy-conversion spectro-analytical methods (e.g., photoacoustic, photothermal, and optogalvanic spectroscopic methods)
07.77.-n Atomic, molecular, and charged-particle sources and detectors
37.20.+j Atomic and molecular beam sources and techniques
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
07.05.Bx Computer systems: hardware, operating systems, computer languages, and utilities

Investigation of leaks in fiberglass‐reinforced pressure vessels by direct observation of hollow fibers in glass cloth

J. McAdams

Rev. Sci. Instrum. 59, 2616 (1988); http://dx.doi.org/10.1063/1.1139908 (2 pages)

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A simple method of visual observation of hollow fibers within fiberglass cloth has been developed. This visualization can aid in determining the contribution these fibers make toward leaks observed in fiberglass‐reinforced epoxy resin pressure or vacuum vessels. Photographs and frequency data of these hollow fibers are provided.
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42.87.-d Optical testing techniques
42.81.Wg Other fiber-optical devices
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Note on the precision cementing of small optical components

A. W. Hartman

Rev. Sci. Instrum. 59, 2617 (1988); http://dx.doi.org/10.1063/1.1139909 (2 pages) | Cited 2 times

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When optical or mechanical components are cemented to a substrate that exhibits errors in surface figure or tilt angle, the possibility exists that these errors will propagate to the work piece. If the cement layer thickness shrinks by a given fraction p, during setting of the cement the error propagation will occur at the same fraction causing losses in flatness, tilt angle, etc. These losses can be reduced to near‐harmless levels (by a fraction p2) by adopting a two‐stage cementing process, involving an intermediate substrate.
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06.60.Vz Workshop procedures (welding, machining, lubrication, bearings, etc.)
07.10.-h Mechanical instruments and equipment

Simple, demountable, cryogenic, vacuum seal

P. Snell, R. R. Turkington, and R. Harris‐Lowe

Rev. Sci. Instrum. 59, 2618 (1988); http://dx.doi.org/10.1063/1.1140263 (2 pages)

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In this note, we describe the fabrication of a simple, reliable, demountable, vacuum seal which can function in the presence of superfluid helium and withstand temperature cycling to room temperature.
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07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment
07.30.Kf Vacuum chambers, auxiliary apparatus, and materials

Nonlinearity corrections for amplitude measurement from Hadamard sums application to a rotating polarizer ellipsometer

Gilbert Zalczer

Rev. Sci. Instrum. 59, 2620 (1988); http://dx.doi.org/10.1063/1.1139910 (2 pages) | Cited 3 times

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In a perfect system, the amplitude of a sinusoidal signal superimposed on a constant background can be determined from Hadamard sums. The simple computation described here allows us to correct a quadratic nonlinearity in the signal detection. Using this procedure, a commercial rotating‐polarizer ellipsometer could be safely operated with signal levels increased by a factor of 15.
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07.60.Fs Polarimeters and ellipsometers
74.20.-z Theories and models of superconducting state
63.10.+a General theory

Automated system for measurement of the effective surface‐charge decay rate of unshielded electrets

Irvin G. Clator

Rev. Sci. Instrum. 59, 2621 (1988); http://dx.doi.org/10.1063/1.1140226 (2 pages)

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A rotating probe assembly suitable for effective surface‐charge decay‐rate measurements is described. Utilizing computer acquistion of data, low resolution charge distribution measurements can be made.
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07.50.-e Electrical and electronic instruments and components
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
81.70.-q Methods of materials testing and analysis

Apparatus for making A/B superlattice Langmuir–Blodgett films

B. Lin, J. B. Peng, P. Dutta, J. B. Ketterson, and G. Wong

Rev. Sci. Instrum. 59, 2623 (1988); http://dx.doi.org/10.1063/1.1140274 (2 pages)

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We report a modification recently made to a Langmuir–Blodgett superlattice apparatus previously described in this journal. The modification permits the preparation of so‐called A/B superlattices consisting of the sequence ABAB⋅⋅⋅, where A and B are monolayers of two different film‐forming molecules deposited into a multilayer structure.
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81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Simple interface between electrochemical systems and FTIR spectrometers

R. Holze, U. Freisenich, and W. Stach

Rev. Sci. Instrum. 59, 2625 (1988); http://dx.doi.org/10.1063/1.1140227 (2 pages) | Cited 2 times

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An electronic interface connecting the potentiostat of an electrochemical measurement system to a Fourier transform infrared (FTIR) spectrometer as used for in situ IR reflection absorption studies is described. It makes use of readily available components, is installed without any changes in the hardware of the spectrometer or the potentiostat, and allows fast and reliable spectroelectrochemical measurements.
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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
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

Simple method of measuring vibration amplitudes at better than nanometer sensitivity

T. J. Greaves and F. L. Curzon

Rev. Sci. Instrum. 59, 2626 (1988); http://dx.doi.org/10.1063/1.1140228 (3 pages)

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See Also: Erratum

Show Abstract
It is shown that vibrations driven at fixed frequencies of a few kilohertz can be studied, with displacement sensitivities in the nanometer range, by thermally modulating the length of one arm of a Michelson interferometer, and analyzing the photomultiplier output with a sampling oscilloscope and a spectrum analyzer. This method of measurement has the advantage that the high sensitivity can be attained without a constant temperature enclosure for the interferometer.
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06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
07.60.Ly Interferometers

Applications for an ultraprecise mass spectrometer requested

E. Koets

Rev. Sci. Instrum. 59, 2629 (1988); http://dx.doi.org/10.1063/1.1140229 (1 page) | Cited 1 time

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A mass spectrometer with a potential error in the 10−12 range (i.e., 1 meV/amu) is inactive now. The machine will be scrapped soon, unless suitable applications (and funding) are found or an interested institute acquires the instrument.
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07.75.+h Mass spectrometers
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
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