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Feb 1998

Volume 69, Issue 2, pp. 337-1203

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Development of a femtosecond diffuse reflectance spectroscopic system, evaluation of its temporal resolution, and applications to organic powder systems

Tsuyoshi Asahi, Akihiro Furube, Hiroshi Fukumura, Musubu Ichikawa, and Hiroshi Masuhara

Rev. Sci. Instrum. 69, 361 (1998); http://dx.doi.org/10.1063/1.1148668 (11 pages) | Cited 23 times

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An ultrafast time-resolved diffuse reflectance spectroscopic system has been developed as a potential instrument for analyzing photophysical and photochemical dynamics of light scattering materials such as powder and opaque suspension, using an amplified femtosecond Ti:sapphire laser as a light source. Transient absorption spectra of organic powder, covering the wavelength region from 400 to 760 nm, were precisely obtained by using a stable and bright femtosecond white-light continuum as a probe light. An ultrashort light pulse is temporally broadened owing to numerous times of refraction, reflection, and diffraction in scattering materials. This affects the temporal resolution of transient absorption measurements, which was examined and discussed in detail by using a simple numerical model with time-dependent light propagation of a short pulse. From the simulation and experimental results, it was shown that the temporal resolution of transient absorption measurement is less than a few ps under a certain measurement condition, although it strongly depends on the optical properties of the sample; scattering and absorption coefficients. Some applications to the analysis of excited dynamics of organic molecules in polymer latex and molecular microcrystalline powder are also demonstrated. © 1998 American Institute of Physics.
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07.60.Rd Visible and ultraviolet spectrometers
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
78.47.-p Spectroscopy of solid state dynamics

Noise characterization of a coherent tunable far infrared spectrometer

S. Viciani, F. Marin, and P. De Natale

Rev. Sci. Instrum. 69, 372 (1998); http://dx.doi.org/10.1063/1.1148669 (5 pages) | Cited 3 times

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The different noise contributions in a coherent tunable far infrared spectrometer were measured. On the basis of this quantitative analysis, several experimental schemes to enhance the sensitivity for spectroscopy in this spectral region are proposed. In particular, a full theoretical analysis for differential detection is developed. A double-detector scheme is theoretically analyzed and it is shown that a noise reduction of up to 17 dB is achievable with this configuration. The present work should make possible quantitative forecasting of sensitivity enhancement for new, different experimental configurations. © 1998 American Institute of Physics.
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07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
72.70.+m Noise processes and phenomena

A photospectrometer realized in a standard integrated circuit process

Michael L. Simpson, William B. Dress, M. Nance Ericson, Gerald E. Jellison, David N. Sitter, Alan L. Wintenberg, and David F. French

Rev. Sci. Instrum. 69, 377 (1998); http://dx.doi.org/10.1063/1.1148457 (7 pages) | Cited 4 times

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A photospectrometer has been realized in a standard integrated circuit (IC) process. Only the masks, materials, and fabrication steps inherent to this IC process were used (i.e., no post processing to add mechanical or optical devices for filtering). The spectrometer was composed of a set of 18 photodetectors with independent spectral responses. The responses of these devices were weighted and summed to form outputs proportional to the input optical power in discrete wavelength bands in the region from ∼ 400 to ∼ 1100 nm. With the solution space restricted to a 60 nm band, this instrument could resolve Gaussian input spectra (σ = 5 nm) with a peak-to-peak spacing of less than 15 nm. This device could easily be integrated with additional analog, digital, or wireless circuits to realize a true laboratory instrument on-a-chip. © 1998 American Institute of Physics.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
07.60.Dq Photometers, radiometers, and colorimeters
85.60.Dw Photodiodes; phototransistors; photoresistors
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
07.60.Rd Visible and ultraviolet spectrometers
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques

A fast detector using stacked avalanche photodiodes for x-ray diffraction experiments with synchrotron radiation

S. Kishimoto, N. Ishizawa, and T. P. Vaalsta

Rev. Sci. Instrum. 69, 384 (1998); http://dx.doi.org/10.1063/1.1148670 (8 pages) | Cited 10 times

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We have developed a fast detector using stacked avalanche photodiodes (APDs) for x-ray diffraction experiments with synchrotron radiation. This detector has four independent channels of APDs, and the detector efficiency has reached 55% in all for 16.53 keV x rays. Since the dead time of the counting system is shorter than 4 ns, output rates of up to 4.5×108 counts/s have been obtained for 16.53 keV x rays. The dynamic range is more than 1010 in the multibunch mode of a storage ring. Pulse-height measurements at output rates of up to 108 counts/s were successfully carried out by sequential single-channel discrimination. © 1998 American Institute of Physics.
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07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
61.05.C- X-ray diffraction and scattering
85.60.Dw Photodiodes; phototransistors; photoresistors

Continuum x-ray source as a calibration system for charge coupled devices

K. Hashimotodani, T. Toneri, S. Kitamoto, H. Tsunemi, K. Hayashida, E. Miyata, K. Katayama, T. Kohomura, R. Asakura, K. Koyama, K. Yamamoto, K. Miyaguchi, and H. Suzuki

Rev. Sci. Instrum. 69, 392 (1998); http://dx.doi.org/10.1063/1.1148671 (4 pages) | Cited 4 times

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We present x-ray spectra obtained by a charge coupled device (CCD) from an electron impacting x-ray source using several kinds of electron targets: Au, Al–bronze, Al, and pure Al. The x rays from the source are dispersed by a grating and the dispersed x rays are focused on the CCD. Owing to the fine spatial and moderate energy resolutions of the CCD, fine spectra with 2 eV energy resolution up to 2.2 keV are obtained. X rays from the pure Al target (99.999% purity) provide good continuum x rays except for Al K x rays. This continuum source is useful as a calibration source for low energy x-ray detectors. © 1998 American Institute of Physics.
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07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
42.79.Pw Imaging detectors and sensors
85.60.Gz Photodetectors (including infrared and CCD detectors)
06.20.F- Units and standards
07.85.Nc X-ray and γ-ray spectrometers

Measuring the instantaneous arrival times of a long series of consecutive photoevents

Dimitar V. Stoyanov

Rev. Sci. Instrum. 69, 396 (1998); http://dx.doi.org/10.1063/1.1148672 (6 pages) | Cited 3 times

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A novel technique for measuring the instantaneous arrival times of a long series of consecutive photoevents effective at shorter intrapulse intervals up to 10 ns with an accuracy of better than 1 ns has been developed and tested experimentally and by simulations. It is based on linear processing without dead time effects of detector pulses by excitation of a resonant system, analog/digital sampling, deconvolution, and calculation of single pulse centers and electric charges. The maximum number of processed photoevents exceeds 103 at 108 pulse rate. In an accumulation regime the method can be used for temporal profiling of the number of photocounts with very high resolutions up to 0.1 ns. This method covers the intermediate range of photon rates, where the well known techniques are ineffective. It can be applied for high order photon statistics, in lidar sensing, time-resolved spectroscopy, as well as in typical electronic measurements of instantaneous frequencies, periods etc. © 1998 American Institute of Physics.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
85.60.Ha Photomultipliers; phototubes and photocathodes
06.60.Jn High-speed techniques (microsecond to femtosecond)
06.30.Ft Time and frequency
84.30.Sk Pulse and digital circuits
42.50.Ar Photon statistics and coherence theory
07.60.Dq Photometers, radiometers, and colorimeters

Portable autocollimators using the laser diode and the position sensitive detector

Yeung J. Sohn, Jin H. Kwon, Ok S. Choe, and Tae B. Eom

Rev. Sci. Instrum. 69, 402 (1998); http://dx.doi.org/10.1063/1.1148673 (4 pages) | Cited 6 times

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We were able to simplify the structure of the autocollimators and enhance the performance by using one- and two-axis PSDs (position-sensitive detectors) which have spatial resolution of 0.1 and 2.5 μm, respectively, with little dependence on the spot size of incident beam and the visible laser diodes as the light source. Two kinds of portable autocollimators which can measure angles with resolutions 0.01″ and 0.1″, respectively, were made. They were calibrated by the reference angle generator which employed the laser interferometer. The characteristics of temporal stability were evaluated and the profile of a test surface was measured. © 1998 American Institute of Physics.
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42.79.Ag Apertures, collimators
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy
07.60.Ly Interferometers

Construction and characterization of a short pulse slit-jet source based upon the current loop-actuated design

Thomas Müller and Patrick H. Vaccaro

Rev. Sci. Instrum. 69, 406 (1998); http://dx.doi.org/10.1063/1.1148674 (6 pages) | Cited 5 times

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A pulsed slit-jet expansion source capable of generating moderate velocity-collimated pathlengths ( ∼ 1 cm) of rovibronically cooled target molecules for spectroscopic interrogation is described and characterized. Based upon the modification of a commercially available current loop-actuated design, this apparatus produces conductance-limited pulses of ⩽ 50 μs duration at repetition rates of up to 20 pps. The short temporal length of the emerging gas pulse greatly alleviates the demands imposed upon vacuum pumping systems and enables the use of higher stagnation pressures in the expansion process. © 1998 American Institute of Physics.
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37.20.+j Atomic and molecular beam sources and techniques
07.60.Rd Visible and ultraviolet spectrometers
47.40.Ki Supersonic and hypersonic flows
85.70.-w Magnetic devices

Ion optics for multiple charge exchange collisions determined by means of Monte Carlo simulation

T. Takeuchi, T. Yamagata, K. Yonehara, Y. Arimoto, and M. Tanaka

Rev. Sci. Instrum. 69, 412 (1998); http://dx.doi.org/10.1063/1.1148719 (6 pages)

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A novel type of polarized 3He ion source based on “electron pumping” was recently proposed. This ion source requires multiple electron capture and stripping collisions of 3He+ ions with polarized alkali atoms under a strong magnetic field (2–3 T). Since these processes may induce a serious increase in the emittance and reduction of polarized beam intensity, we investigated them in detail by using the Monte Carlo simulation. It was found that there is (1) increase in the emittance results not from angular broadening but from a beam size enlargement, (2) the phenomena under magnetic field B are simplified by a collisionless phenomenon under a weaker magnetic field (effective magnetic field) Beff defined by Beff ≃ (λ+0/(λ+0+λ0+))B, where λ+0 and λ0+ are mean free paths for 3He+ ions and 3He0 atoms traveling in the alkali vapor. © 1998 American Institute of Physics.
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29.25.Lg Ion sources: polarized
41.85.-p Beam optics
34.70.+e Charge transfer
02.70.Rr General statistical methods
07.77.Ka Charged-particle beam sources and detectors
29.25.Ni Ion sources: positive and negative

Kilovolt x-ray scattering from a plasma

Nigel C. Woolsey, David Riley, and Eran Nardi

Rev. Sci. Instrum. 69, 418 (1998); http://dx.doi.org/10.1063/1.1148675 (7 pages) | Cited 13 times

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We describe a diagnostic suitable for the investigation of strong coupling effects in a plasma. The diagnostic is based on x-ray scattering of kilovolt x rays from a plasma and the determination of total x-ray scattering cross sections. The first experimental results of the total scattering cross sections from a strongly coupled plasma measured with kilovolt x rays are presented. The scattering plasma is formed by radiatively heating an Al foil with soft x rays created by Au laser-conversion foil; the plasma is probed with Ti XXII 1s2–1s2p line x rays emitted from a second laser produced plasma. A detailed description of the scattering technique is presented and the potential of x-ray scattering as a diagnostic of strongly coupled plasmas is explored. © 1998 American Institute of Physics.
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52.70.La X-ray and γ-ray measurements
07.85.-m X- and γ-ray instruments

Measurement of plasma density using wavelet analysis of microwave reflectometer signal

L. G. Bruskin, A. Mase, T. Tokuzawa, N. Oyama, A. Itakura, and T. Tamano

Rev. Sci. Instrum. 69, 425 (1998); http://dx.doi.org/10.1063/1.1148676 (6 pages) | Cited 9 times

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A new method of plasma density profile reconstruction in microwave reflectometry is proposed and implemented on an X-mode broadband reflectometer of the GAMMA 10 mirror device with an ultrafast sweep rate of 10–20 μs. The proposed method makes use of the wavelet transform of the detected signal. Excellent resolution in the time-frequency domain, inherent to wavelet analysis, allows one to obtain a radial electron density profile for every frequency sweep. The electron density reconstruction algorithm, besides the wavelet transform of the reflectometer signal, also includes the calibration, profile initialization, and the solution of an integral equation, ultimately yielding the local values of the electron density. Calibration of the measured signal phase and profile initialization is performed using the independent results of microwave interferometry. Inversion of the integral equation is implemented utilizing the gradient method, numerically stable even for plasma regions with steep density gradients and density profile plateaus. A wavelet-based profile reconstruction algorithm is especially advantageous for monitoring transient plasma phenomena and fast processes, such as in pellet injection, ultrafast swept reflectometry, and short pulsed reflectometry. © 1998 American Institute of Physics.
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52.70.Gw Radio-frequency and microwave measurements
02.30.Uu Integral transforms
02.30.Vv Operational calculus
28.52.Av Theory, design, and computerized simulation
52.55.-s Magnetic confinement and equilibrium

A moving coil ac magnetic susceptometer

R. R. de Souza and C. J. Magon

Rev. Sci. Instrum. 69, 431 (1998); http://dx.doi.org/10.1063/1.1148677 (6 pages) | Cited 3 times

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A mutual inductance bridge which may be used for automatic measurement of ac magnetic susceptibilities from 4 K to room temperature at frequencies up to 1 kHz is described. An alternative and new arrangement of the probe is described in details. The coil set is kept at room temperature and moves in such a way to place the sample in the center of each of the secondary coils. The sample, motionless, has its temperature controlled by a helium flow refrigerator. Use of a magnetic shield minimizes coupling of the probe with nearby magnetic materials. The movement of the probe and the operation of the bridge are fully controlled by a personal computer. This probe has a sensitivity of 10−7 emu in an ac magnetic field of 8 G rms and frequency of 100 Hz. The frequency range employed can easily be extended to 10 kHz without seriously affecting the accuracy of the measurements. © 1998 American Institute of Physics.
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07.55.Jg Magnetometers for susceptibility, magnetic moment, and magnetization measurements
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment

A simple chemical etching technique for reproducible fabrication of robust scanning near-field fiber probes

Yung-Hui Chuang, Kuo-Gung Sun, Chia-Jen Wang, J. Y. Huang, and Ci-Ling Pan

Rev. Sci. Instrum. 69, 437 (1998); http://dx.doi.org/10.1063/1.1148678 (3 pages) | Cited 14 times

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A two-step chemical etching procedure has been developed for fabricating probes used by scanning near-field optical microscopy. These probes have two tapered regions which can be reproducibly constructed with a wide range of cone angles. The shape of the probe allows it to be used over sample surfaces with deep and narrow regions. Furthermore, our method can be applied to silica glass fibers which are commercially available. To demonstrate, we used these tips to acquire the near-field optical image of a thin layer of polystyrene spheres. Intensity interference patterns were observed. The demonstrated in-plane resolution was estimated to be about 250 nm. This is mainly limited by the diameter of the metal-coated tip. The transmission efficiency of the tip is better than 10−4. © 1998 American Institute of Physics.
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07.79.Fc Near-field scanning optical microscopes
07.60.Vg Fiber-optic instruments
42.81.Bm Fabrication, cladding, and splicing
81.65.Cf Surface cleaning, etching, patterning
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 new surface science in situ transmission and reflection electron microscope

M. T. Marshall, M. L. McDonald, X. Tong, M. Yeadon, and J. M. Gibson

Rev. Sci. Instrum. 69, 440 (1998); http://dx.doi.org/10.1063/1.1148679 (8 pages) | Cited 11 times

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We describe an ultrahigh vacuum instrument for transmission electron microscopy and reflection electron microscopy for the study of surfaces and thin film growth. The focus of previous experiments was on the high spatial resolution (<3 Å) generally associated with microscopy, at the cost of controlled growth and characterization. We have taken a different approach. It has been shown that most experiments using diffraction and diffraction contrast imaging can be performed well at poorer resolution (∼20 Å), including the imaging of monatomic steps and monolayer coverages. The instrument is designed for best control of growth and vacuum, with sacrifices in optical resolution, which is theoretically ∼2 nm. The instrument is called SHEBA (surface high-energy electron beam apparatus). We can examine a ∼ 1 cm2 sample in both transmission electron microscopy and reflection electron microscopy, in situ with well-controlled molecular beam epitaxy (MBE) growth capabilities, well characterized vacuum, and surface characterization by Auger spectroscopy and low-energy electron diffraction. Preliminary experiments of cobalt on silicon have shown MBE growth rates ranging from 1.5 monolayers per hour to 18.3 monolayers per hour depending on the temperature of the evaporation source. Using SHEBA for a reactive MBE experiment has provided the first direct evidence of the formation of aluminum nitride by nitridation of basal plane sapphire. The most serious design problems were stray magnetic fields and mechanical vibrations. These have been overcome and allow a spatial resolution of <10 nm. The instrument is expected to be very valuable in studies of film growth. © 1998 American Institute of Physics.
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68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
07.30.Kf Vacuum chambers, auxiliary apparatus, and materials

A compact superconducting magnet for magnetic resonance microscopy

Stuart Crozier and David M. Doddrell

Rev. Sci. Instrum. 69, 448 (1998); http://dx.doi.org/10.1063/1.1148680 (4 pages) | Cited 2 times

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Magnetic resonance microscopy (MRM) depends on the use of high field, superconducting magnet systems for its operation. The magnets that are conventionally used are those that were initially designed for chemical structural analysis work. A novel, compact magnet designed specifically for MRM is presented here, and while preserving high field, high homogeneity conditions, has a length less than one-third that of conventional systems. This enables much better access to samples, an important consideration in many MRM experiments. As the homogeneity of a magnet is strongly dependent on its length, novel geometries and optimization techniques are required to meet the requirements of MRM in a compact system. An important outcome of the stochastic optimization performed in this work, is that the use used of a thin superconducting solenoid surrounded by counterwound disk windings provides a mechanism for drastic length reductions over conventional magnet designs. © 1998 American Institute of Physics.
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07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques
84.71.Ba Superconducting magnets; magnetic levitation devices
02.60.Pn Numerical optimization

Differential displacement measurement using scanning x-ray beams

Howard A. Canistraro, Eric H. Jordan, and Douglas M. Pease

Rev. Sci. Instrum. 69, 452 (1998); http://dx.doi.org/10.1063/1.1148681 (5 pages) | Cited 1 time

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A noncontacting method for measuring mechanical strain between two fiducial marks has been developed for use where environmental conditions would be disruptive to methods utilizing optical light. A silicon 111 Johansson crystal is used for this application where Mo Kα radiation is used to fluoresce fiducial markers made of yittria-stabilized zirconia. This substance is used for a thermal barrier coating in gas turbine engines and the technology for applying this material to withstand long term high temperature exposure is highly developed. The current system has a displacement repeatability of better than 0.1 μm which is not limited by counting statistics, but rather determined by mechanical considerations. © 1998 American Institute of Physics.
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07.10.Pz Instruments for strain, force, and torque
81.70.-q Methods of materials testing and analysis
07.85.-m X- and γ-ray instruments
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)

Broad band and absolute measurement of transient dynamic normal velocity of surface

Byoung-Geuk Kim, Manabu Enoki, and Teruo Kishi

Rev. Sci. Instrum. 69, 457 (1998); http://dx.doi.org/10.1063/1.1148682 (3 pages)

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Broad band direct sensing of the transient dynamic normal velocity of an object surface and evaluating its absolute value were realized by using a sensor fabricated with a piezoelectric polyvinylidene fluoride film and a polyvinyl chloride (PVC) back load and a PVC wear plate. The transient output signal from the sensor obtained by a test employing a well-defined steplike force, at the epicenter of a steel plate, showed very good agreement with the dynamic normal velocity calculated by using a Green’s function and a simulated source function. The output was proportional to the dynamic normal velocity of the surface, and the frequency-dependent sensitivity for the velocity was flat within a deviation of ±3.8 dB for the average in the frequency range up to 2 MHz. The transient dynamic normal velocity of the surface could be absolutely determined by using a sensor calibrated by theoretical one. © 1998 American Institute of Physics.
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06.30.Gv Velocity, acceleration, and rotation
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
43.38.Fx Piezoelectric and ferroelectric transducers
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)

Optical deflection setup for stress measurements in thin films

M. Bicker, U. von Hülsen, U. Laudahn, A. Pundt, and U. Geyer

Rev. Sci. Instrum. 69, 460 (1998); http://dx.doi.org/10.1063/1.1148721 (3 pages) | Cited 13 times

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We demonstrate an optical two-beam deflection setup for in situ stress measurements in thin films. By using improved position sensitive photodetectors we reach a resolution of better than 10−4 m−1 for substrate curvature measurement at a bandwidth of 1 kHz, with a relatively short optical path of 0.53 m and without employing a lock-in technique. © 1998 American Institute of Physics.
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83.85.Ei Optical methods; rheo-optics
42.79.Fm Reflectors, beam splitters, and deflectors
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy
83.85.Lq Normal stress difference measurements
68.60.Bs Mechanical and acoustical properties
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
85.60.Gz Photodetectors (including infrared and CCD detectors)

A tensile stage to study thin polymer films in an environmental scanning electron microscope

V. Thomas and A. Wolfenden

Rev. Sci. Instrum. 69, 463 (1998); http://dx.doi.org/10.1063/1.1148720 (3 pages) | Cited 1 time

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An economical and easily constructed tensile stage to study thin polymer films in an environmental scanning electron microscope has been developed. Surface features of the film and the morphology in the vicinity of a crack tip while under stress may be studied using this stage. The construction, sample mounting technique, and some of the photomicrographs obtained using this tensile stage have been illustrated and described. © 1998 American Institute of Physics.
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81.70.Bt Mechanical testing, impact tests, static and dynamic loads
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
06.60.Ei Sample preparation (including design of sample holders)
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)
68.60.Bs Mechanical and acoustical properties
68.55.-a Thin film structure and morphology

Automated measuring instrument of the surface electric potential and potential distribution

S. Sakalauskas and A. Sodeika

Rev. Sci. Instrum. 69, 466 (1998); http://dx.doi.org/10.1063/1.1148683 (3 pages) | Cited 3 times

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An automated measuring instrument of the surface electric potential and its distribution was presented. The schematic instrument diagram, metrological assessment, the relation of measured voltage with the sample electrophysical parameters are discussed. Possibilities of measuring instruments are demonstrated by some physical investigations. © 1998 American Institute of Physics.
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84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)

A novel sensitive method of surface impedance measurement for small samples

C. C. Chin

Rev. Sci. Instrum. 69, 469 (1998); http://dx.doi.org/10.1063/1.1148684 (5 pages)

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We propose a novel sensitive method of surface impedance measurement for small samples utilizing a YIG delay line. We will give a full analysis of the relationship between the phase and amplitude of the signals to surface impedance. The sensitivity of this method will be fully addressed. The dispersion relations of magnetostatic waves guided by lossy ground planes will also be given as byproducts of the above analysis. © 1998 American Institute of Physics.
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84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)
75.70.Rf Surface magnetism
85.70.Ec Magnetostrictive, magnetoacoustic, and magnetostatic devices

Large area deposition of YBa2Cu3O7−x films by pulsed laser ablation

B. Schey, T. Bollmeier, M. Kuhn, W. Biegel, and B. Stritzker

Rev. Sci. Instrum. 69, 474 (1998); http://dx.doi.org/10.1063/1.1148685 (3 pages) | Cited 7 times

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A special patented design is built up to produce homogeneous YBa2Cu3O7−x (YBCO) films by pulsed laser deposition (PLD) over areas as large as 7×20 cm2. The use of a line focus (8 cm) reduces the substrate movement to one dimension. The demands on plasma homogenization, substrate scanning and film temperature during the deposition process for large area PLD are discussed and their technical realization is presented. First results of 1×1 cm2 YBCO films at different positions on the substrate holder (11×28 cm2) show homogeneous deposition conditions. The transition temperatures of the deposited YBCO thin films on 1×1 cm2 SrTiO3 substrates are TC = 89 K with critical currents of 4×106 A/cm2 at T = 77 K. The structural properties of these films (χmin = 4.5%) indicate also their high crystalline quality. The variation of film thickness perpendicular to the scanning direction is less than ±9% and along the scanning direction ±7%. © 1998 American Institute of Physics.
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81.15.Fg Pulsed laser ablation deposition
68.55.-a Thin film structure and morphology
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors
74.62.Bf Effects of material synthesis, crystal structure, and chemical composition

Single-input double-tuned circuit for double resonance nuclear magnetic resonance experiments

Sanlin Hu, Jeffrey A. Reimer, and Alexis T. Bell

Rev. Sci. Instrum. 69, 477 (1998); http://dx.doi.org/10.1063/1.1148458 (2 pages) | Cited 7 times

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A single-input double-tuned probe was designed for double resonance nuclear magnetic resonance (NMR) experiments, in which high radio frequency power irradiations were achieved at two closely spaced frequencies (such as 26.1 MHz for 27Al and 28.4 MHz for 65Cu). The efficiency of the probe for both nuclei was determined to be about 80%, compared to that obtained with a single-tuned probe. The probe was used successfully for 27Al–65Cu SEDOR experiments to derive the internuclear distance between Al and Cu in Cu-ZSM-5 zeolite. The circuit is ideal for SEDOR-type double resonance NMR experiments, when high power irradiation is required for nuclei with closely spaced resonance frequencies. © 1998 American Institute of Physics.
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07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques
76.70.Fz Double nuclear magnetic resonance (DNMR), dynamical nuclear polarization
61.05.Qr Magnetic resonance techniques; Mössbauer spectroscopy (for structure determination only)
76.60.-k Nuclear magnetic resonance and relaxation

Nuclear magnetic resonance in a diamond anvil cell at very high pressures

Michael G. Pravica and Isaac F. Silvera

Rev. Sci. Instrum. 69, 479 (1998); http://dx.doi.org/10.1063/1.1148686 (6 pages) | Cited 15 times

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We describe a novel design to study the nuclear magnetic resonance (NMR) properties of materials at high pressure in a diamond anvil cell. A split gasket is used to pressurize the sample and a single turn coil couples the rf field with the sample. Due to the large filling factor, this method has a significantly increased sensitivity compared to previously used techniques and should allow NMR study of materials in a diamond anvil cell into the megabar region. We demonstrate the system with a measurement of the spin-lattice relaxation (T1) of cyclohexane as a function of pressure at 79 K up to 9.7 GPa. We have also pressurized a sample of hydrogen to 26 GPa. © 1998 American Institute of Physics.
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07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
76.60.Es Relaxation effects

Ion beam source for soft-landing deposition

J. P. Biesecker, G. B. Ellison, H. Wang, M. J. Iedema, A. A. Tsekouras, and J. P. Cowin

Rev. Sci. Instrum. 69, 485 (1998); http://dx.doi.org/10.1063/1.1148459 (11 pages) | Cited 7 times

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“Soft-landing” deposition of molecular ions on various surfaces is important in making exotic radicals, modeling electrochemical double layers, and studying aqueous ion interactions. We have built a new mass-selected ion beam source for soft-landing deposition, designed to produce either positive or negative ions, including ions that depend on ion-neutral reactions (e.g., H3O+ and NH4+). The ionizer is a free jet crossed by an electron beam, producing a wide variety of positive and negative ions. The simple, short-length, planar ion deceleration minimizes defocusing and space charge effects. It currently delivers mass-selected ions with energies down to about 1 eV and currents of about 10 nA. The design allows easy maintenance. The performance of the ion beam compares favorably with previous low-energy positive ion systems. © 1998 American Institute of Physics.
Show PACS
07.77.Ka Charged-particle beam sources and detectors
29.25.Ni Ion sources: positive and negative
34.90.+q Other topics in atomic and molecular collision processes and interactions (restricted to new topics in section 34)
81.15.Jj Ion and electron beam-assisted deposition; ion plating
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