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Feb 1987

Volume 58, Issue 2, pp. 167-321

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Large format imaging photon detector for astronomical spectroscopy

M. Clampin and R. P. Edwin

Rev. Sci. Instrum. 58, 167 (1987); http://dx.doi.org/10.1063/1.1139302 (7 pages) | Cited 1 time

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We describe the design and development of a large format 40‐mm active diameter imaging photon detector. The design comprises an S20 semitransparent photocathode proximity focused onto a stack of two microchannel plates clamped back to back having channel length to diameter ratios of 80:1. Event readout is facilitated by a circular arc terminated resistive anode. The theoretical performance of the design is discussed with reference to gain measurements of the microchannel plates. Experimental results give an optimum position resolution of 100 μm which is spatially nonuniform and degrades towards the edge of the imaging field. We discuss the role of signal processing in this nonuniformity and describe design modifications which would achieve optimum imaging performance.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
95.55.Sh Auxiliary and recording instruments; clocks and frequency standards
95.55.Qf Photometric, polarimetric, and spectroscopic instrumentation

New scanning transmission electron microscope microanalytical system

N. William Parker, Richard K. Mittleman, and Albert V. Crewe

Rev. Sci. Instrum. 58, 174 (1987); http://dx.doi.org/10.1063/1.1139655 (9 pages) | Cited 2 times

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We have designed and built an improved, dedicated analytical scanning transmission electron microscope (STEM). A novel feature of this microscope is a magnetic lens above the accelerating gun, allowing the specimen probe to achieve very high current densities while retaining the high spatial resolution of the STEM. Integrated with this microscope, we have also implemented an image processing system which allows rapid analysis of the digitized microscope output signals. This processing system also allows the graphic simulation of planar materials (such as intercalated graphite) to derive diffraction pattern simulations for comparison with the experimental data. An image database system allows over 2000 images to be easily managed.
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07.78.+s Electron, positron, and ion microscopes; electron diffractometers
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination

Apparatus for simultaneous light scattering and microscopic video observation: Application to the growth of a droplet pattern

F. Perrot and D. Beysens

Rev. Sci. Instrum. 58, 183 (1987); http://dx.doi.org/10.1063/1.1139303 (2 pages) | Cited 5 times

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A simple apparatus is described which allows the simultaneous microscopic observation of a pattern and the analysis of the light scattered by it at low angles using a single video image. Applications are found any time a spatial Fourier analysis is needed in addition to a simple visualization. As an example, we report a preliminary study of the growth of ‘‘breath figures’’—a pattern formed by the condensation of vapor blown onto a cold surface.
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42.87.-d Optical testing techniques
42.25.Fx Diffraction and scattering
78.20.-e Optical properties of bulk materials and thin films

Timing control unit for enhancing vidicon linearity in pulsed laser spectroscopy with the OMA 1205

Ralf Menzel

Rev. Sci. Instrum. 58, 185 (1987); http://dx.doi.org/10.1063/1.1139304 (4 pages) | Cited 3 times

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A special timing control unit to synchronize the OMA 1205 with a SIT vidicon for a pulsed laser apparatus has been developed. Under special timing conditions the range of linearity of the vidicon response can be enhanced by a factor of 25. The results for the vidicon response as a function of illumination intensity under the realistic conditions of a transient state measurement are presented together with reference data obtained without utilizing the unit. In both cases optimum linearity is achieved with counting rates of about 20 counts/shot only.
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07.60.Rd Visible and ultraviolet spectrometers
07.07.Hj Display and recording equipment, oscilloscopes, TV cameras, etc.
42.79.-e Optical elements, devices, and systems

Optical properties of the retroreflective array in spectroscopic instrumentation

Konan Peck and Michael D. Morris

Rev. Sci. Instrum. 58, 189 (1987); http://dx.doi.org/10.1063/1.1139305 (8 pages)

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The distribution of retroreflected light from an array of corner cube prisms is measured as a function of angle of incidence and beam collimation. The imaging properties of the array are compared to those of a plane mirror in the presence and absence of phase perturbations. The implications for the use of a retroreflective array in absorbance measuring instrumentation are discussed.
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42.79.Bh Lenses, prisms and mirrors
42.15.Eq Optical system design
42.87.-d Optical testing techniques

Simple electronic device for position‐sensitive detectors in VUV spectrometry

G. Chauvet, A. Brenac, and R. Baptist

Rev. Sci. Instrum. 58, 197 (1987); http://dx.doi.org/10.1063/1.1139306 (5 pages) | Cited 4 times

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This paper describes a simple and low‐cost electronic device which calculates the position of an incident VUV photon on a commercially available position‐sensitive detector composed of two multichannel plates and a resistive anode. The readout method used consists of a position‐time conversion during data acquisition and a subsequent transformation of the collected data by a personal computer (Apple IIe). Applications to VUV spectrometry in atomic physics, showing spectra of 400 Å width with a resolution of about 15 Å, bring out advantages and drawbacks of this system.
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07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
29.40.Gx Tracking and position-sensitive detectors

Position‐sensitive photodetector based on hydrogenated amorphous silicon p‐i‐n junctions

V. A. Chumak, M. Bertolotti, A. Ferrari, F. Bartoloni, and F. Evangelisti

Rev. Sci. Instrum. 58, 202 (1987); http://dx.doi.org/10.1063/1.1139307 (5 pages) | Cited 4 times

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A position‐sensitive photodetector is discussed using the transverse photoeffect and a particular geometry in a hydrogenated amorphous silicon (a‐Si:H) junction. A comparison with a more conventional device using the lateral photoeffect in a‐Si:H is made and it is shown that the new device has better characteristics.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
29.40.Wk Solid-state detectors
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors

Translation stage for a scanning x‐ray optical interferometer

P. Becker, P. Seyfried, and H. Siegert

Rev. Sci. Instrum. 58, 207 (1987); http://dx.doi.org/10.1063/1.1139308 (5 pages) | Cited 9 times

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A translation stage is described which allows rectilinear displacements of up to 200 μm with a load of 20 N. Lateral deviations from the rectilinear movement do not exceed a few nanometers. Tilts are reduced to a few nanoradians. By means of a piezoelectric drive, slow continuous motion with vibration amplitudes below 0.1 nm is achieved. Residual tilting errors due to machining tolerances and nonideal coupling of the drive are reduced to nrad levels by magnetic compensation elements which are remote controlled.
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07.85.-m X- and γ-ray instruments
07.10.-h Mechanical instruments and equipment

Thin‐film x‐ray analysis using the Read camera: A refinement of the technique

K. Tao and C. A. Hewett

Rev. Sci. Instrum. 58, 212 (1987); http://dx.doi.org/10.1063/1.1139309 (3 pages) | Cited 2 times

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The accuracy of lattice parameter determinations by Read camera x‐ray diffraction is shown to be strongly dependent on camera alignment. Alignment of the Read camera eliminates the main sources of error. Further improvement in analysis was achieved by constructing a collimator with a rectangular cross section. Analysis and testing showed that the rectangular collimator enhances the efficiency, resolution, precision, and peak‐to‐background intensity ratio for x‐ray analysis of thin films using the Read camera.
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61.05.cf X-ray scattering (including small-angle scattering)
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
07.85.-m X- and γ-ray instruments
68.35.B- Structure of clean surfaces (and surface reconstruction)

Extension to the 350‐kV negative ion injector for the JAERI tandem accelerator

Eisuke Minehara, Tadashi Yoshida, Shinichi Abe, Shuhei Kanazawa, Yoshihiro Tsukihashi, Katsuzo Horie, and Susumu Hanashima

Rev. Sci. Instrum. 58, 215 (1987); http://dx.doi.org/10.1063/1.1139310 (5 pages)

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An extension to the 350‐kV negative ion injector for the JAERI tandem accelerator was constructed to minimize loss of the beam time due to changing and tuning the ion sources, and to improve substantially the reliability and personal safety in the accelerator operation. Performance during the first operation over three months is reported and discussed in comparison with the previous performance.
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29.25.Lg Ion sources: polarized
29.25.Ni Ion sources: positive and negative
29.20.Ba Electrostatic accelerators
29.20.-c Accelerators

Focusing of multiply charged energetic ions using solenoidal B and radial E lenses

W. Z. Liu, R. Stern, and F. D. Becchetti

Rev. Sci. Instrum. 58, 220 (1987); http://dx.doi.org/10.1063/1.1139311 (3 pages) | Cited 3 times

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Several large‐solid‐angle devices for collecting, at a common focus, multiply charged heavy ions from nuclear reactions have been studied. These devices use axial magnetic fields (solenoids), radial electric fields (coaxial lenses), or a combination of these. Although each system has particular advantages and disadvantages, several designs appear promising for use as practical devices.
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41.75.Ak Positive-ion beams
41.75.Cn Negative-ion beams
41.60.-m Radiation by moving charges
52.70.Nc Particle measurements
29.90.+r Other topics in elementary-particle and nuclear physics experimental methods and instrumentation (restricted to new topics in section 29)

Extraction of H− and D− ions from a large magnetic multipole source

A. J. T. Holmes, L. M. Lea, A. F. Newman, and M. P. S. Nightingale

Rev. Sci. Instrum. 58, 223 (1987); http://dx.doi.org/10.1063/1.1139312 (12 pages) | Cited 37 times

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Results are presented on the production of H− ions in a large (55×31×20 cm3) magnetic multipole discharge, which is sufficiently large to act as the plasma generator for a neutral beam injector. H− ion current densities up to 57 mA/cm2 have been extracted in pulses up to 3 s in length at low energies. When the discharge is operated in deuterium, a maximum D− current density of 27 mA/cm2 is obtained. The scaling laws of the H− production are consistent with production by dissociative attachment to rovibrationally excited molecules and loss by mutual recombination.
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52.75.Di Ion and plasma propulsion
52.50.Gj Plasma heating by particle beams
52.80.Tn Other gas discharges
29.25.Lg Ion sources: polarized
29.25.Ni Ion sources: positive and negative

Operation of a Dudnikov type Penning source with LaB6 cathodes

K. N. Leung, G. J. DeVries, K. W. Ehlers, L. T. Jackson, J. W. Stearns, M. D. Williams, M. G. McHarg, D. P. Ball, W. T. Lewis, and P. W. Allison

Rev. Sci. Instrum. 58, 235 (1987); http://dx.doi.org/10.1063/1.1139313 (5 pages) | Cited 9 times

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The Dudnikov type Penning source has been operated successfully with low work function LaB6 cathodes in a cesium‐free discharge. It is found that the extracted H− current density is comparable to that of the cesium‐mode operation and H− current density of 350 mA/cm2 have been obtained for an arc current of 55 A. Discharge current as high as 100 A has also been achieved for short pulse durations. The H− yield is closely related to the source geometry and the applied magnetic field. Experimental results demonstrate that the majority of the H− ions extracted are formed by volume processes in this type of source operation.
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29.25.Lg Ion sources: polarized
29.25.Ni Ion sources: positive and negative
52.80.Sm Magnetoactive discharges (e.g., Penning discharges)

Simple time‐resolving Thomson spectrometer

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

Rev. Sci. Instrum. 58, 240 (1987); http://dx.doi.org/10.1063/1.1139314 (5 pages) | Cited 8 times

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We describe a simple time‐resolving Thomson spectrometer system which can provide the temporal information of ions produced by a pulsed source, in addition to the time‐integrated information. The electric field in a conventional spectrometer is modulated by a time‐varying field. It is shown that from the resulting spectrogram, the time‐resolved quantities associated with the ions can be deduced. Experimental results with plasma focus produced ions are given as an example.
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07.75.+h Mass spectrometers
29.25.Lg Ion sources: polarized
29.25.Ni Ion sources: positive and negative
29.30.-h Spectrometers and spectroscopic techniques
52.70.Nc Particle measurements

LEDs and laser diodes in schlieren optics methods

Janusz Pawliszyn

Rev. Sci. Instrum. 58, 245 (1987); http://dx.doi.org/10.1063/1.1139315 (4 pages) | Cited 10 times

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The pointing noise of light beams generated by light emitting diodes (LEDs) and laser diodes are investigated and compared with the stability of the He–Ne laser and the incandescent lamp beam. LEDs have superior pointing noise characteristics compared to other light sources with their angular position drift of only about 50 nrad.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Px Semiconductor lasers; laser diodes
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Schlieren method for measuring the particle density distribution in fusion plasma

G. Lisitano

Rev. Sci. Instrum. 58, 249 (1987); http://dx.doi.org/10.1063/1.1139316 (4 pages)

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This paper describes a measuring system which automatically selects and identifies angularly deflected electromagnetic rays of a pencil beam exploring a dispersive medium. The schlieren deflection is dependent on the refractivity gradient transverse to the ray path. This yields fairly localized measurement of material inhomogeneities. Applied for the first time to a tokamak plasma, this schlieren method yields fast time and good spatial resolution measurement of the particle density distribution. Without any need for data inversion this method also delivers monitor signals of the center‐core peak density and flattening of the parabolic particle density distribution. Schlieren measurements of magnetohydrodynamic particle density perturbation give an insight into plasma transport and collapse mechanisms.
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52.70.Gw Radio-frequency and microwave measurements
42.79.Mt Schlieren devices
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.55.Fa Tokamaks, spherical tokamaks

Optical multichannel analyzer‐based high‐resolution, multipoint spectroscopic apparatus

J. A. Antoniades and T. Peyser

Rev. Sci. Instrum. 58, 253 (1987); http://dx.doi.org/10.1063/1.1139317 (8 pages) | Cited 3 times

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A high‐wavelength resolution (Δλ≤0.02 Å) spectroscopic apparatus has been developed and applied to the measurements of spectral line profiles emitted by thermonuclear plasmas yielding important plasma parameters, such as ion temperature and fluid velocity. The experimental apparatus consists of a spectrometer, an optical multichannel analyzer (OMA), and a lens. It allows precise wavelength measurements (Δλerror≤0.02 Å) when a computer and a ThI electrodeless discharge lamp (EDL) are used to calibrate the instrument. The apparatus yields single‐shot space and time‐resolved spectra for radiation in the 2000–8000‐Å range.
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07.60.Rd Visible and ultraviolet spectrometers
52.70.Kz Optical (ultraviolet, visible, infrared) measurements

High gain, multiatmosphere CO2 laser amplifier

G. C. Stuart, H. Houtman, and J. Meyer

Rev. Sci. Instrum. 58, 261 (1987); http://dx.doi.org/10.1063/1.1139318 (4 pages) | Cited 7 times

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A novel TE discharge, 15‐mm aperture, multiatmosphere, CO2 laser amplifier is described, with measured electrical characteristics and gain measurements on the 9.294‐μm, 9R(16) line. The electrical circuit used in this amplifier is a realistic alternative to the Marx bank or conventional LC inversion circuit and, similarly, it would be useful for excitation of other gas lasers as well. This automatically preionized, double‐sided, fourfold LC inversion circuit uses only one spark gap, and it is shown to provide small‐signal gains of 5.7% cm−1, at 120 J l−1 atm−1 and 10 atm. The generalization to an n–stage device, which would be suitable for higher pressures, and larger apertures, is discussed.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.By Design of specific laser systems
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables
07.50.Ek Circuits and circuit components

All digital inelastic electron tunneling spectrometer utilizing the IEEE‐488 instrument bus and an IBM PC‐XT controller

K. W. Hipps

Rev. Sci. Instrum. 58, 265 (1987); http://dx.doi.org/10.1063/1.1139319 (4 pages) | Cited 5 times

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An easily assembled computer‐controlled tunneling spectrometer is described. Spectral acquisition time is user selectable over a wide range. Low‐resolution spectra may be taken rapidly (about 30s/scan) or very slow scans with long time exponential averaging may be chosen. Data are obtained using a two‐phase lock‐in in magnitude mode so that no phasing of the lock‐in amplifier is required. The advantages of this system are discussed and some representative data presented.
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07.78.+s Electron, positron, and ion microscopes; electron diffractometers
07.05.Hd Data acquisition: hardware and software
07.05.Kf Data analysis: algorithms and implementation; data management
07.05.Rm Data presentation and visualization: algorithms and implementation
07.05.Bx Computer systems: hardware, operating systems, computer languages, and utilities
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination

Precise measurement of dielectric properties at frequencies from 1 kHz to 100 MHz

Akira Kakimoto, Akihiro Etoh, Kaoru Hirano, and Satoshi Nonaka

Rev. Sci. Instrum. 58, 269 (1987); http://dx.doi.org/10.1063/1.1139320 (7 pages) | Cited 16 times

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This paper describes an improved apparatus to measure dielectric constants and dissipation factors using a resonance technique. The measurements can be made rapidly and accurately without appreciable systematic error in the wide frequency range from 1 kHz to 100 MHz. This apparatus uses the half power‐gap variation method or the half power‐varying gap‐immersion method for solid‐plate specimens and the solid‐plate displacement method for liquid specimens. The electrode system is 30 mm in diameter and has a shield ring to avoid the edge capacitance effect, guards against surface current leakage, and variable air capacitors to set the electrode gap at any arbitrary value. To detect a very small power loss, the resonance voltages in circuits with Q≂100 are stabilized to −86 dB at a constant ambient temperature. We use phase detectors so that the electrode gap and the voltage at resonance can easily be read from the digital panel meter and the digital voltmeter. No corrections are necessary even at a high frequency of 100 MHz. The accuracy of measurements made using the half power‐varying gap‐immersion method is within 0.2% for the dielectric constant and 3% for the dissipation factor without marked degradation over the entire frequency range.
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07.50.-e Electrical and electronic instruments and components
77.65.-j Piezoelectricity and electromechanical effects
77.22.Ch Permittivity (dielectric function)

Thin‐film bolometer with fast response

M. Regelsberger, R. Wernhardt, and M. Rosenberg

Rev. Sci. Instrum. 58, 276 (1987); http://dx.doi.org/10.1063/1.1139321 (3 pages) | Cited 1 time

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A short summary on recent developments in semiconducting temperature sensors is given. A thin‐film germanium resistor is described in detail, which is used for fast and accurate thermometry in a nonadiabatic microcalorimeter. The use of only standard vapor deposition techniques makes this sensor also available to research groups lacking access to semiconductor technology. The general good performance and its good mechanical properties have the potential of numerous applications in fast and accurate low‐temperature thermometry.
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07.20.Dt Thermometers
07.20.Fw Calorimeters
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment

New technique for producing highly uniform droplet streams over an extended range of disturbance wavenumbers

M. Orme and E. P. Muntz

Rev. Sci. Instrum. 58, 279 (1987); http://dx.doi.org/10.1063/1.1139322 (6 pages) | Cited 24 times

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A recent discovery about a well‐studied phenomenon leads to the formation of ultracoherent streams of liquid drops. A remarkably straightforward, although previously unreported, method of drop generation from capillary streams, which involves the imposition of an amplitude modulated sinusoidal carrier disturbance, is discussed. The amplitude‐modulated disturbance results in the production of highly stable droplet streams over a previously unattainable range of wavenumbers. A decrease in the speed variation of the drops within the stream, which is a result of the amplitude modulation, is demonstrated over a range of nondimensional wavenumbers from 0.4 to 0.04. The nondimensional wavenumber is the ratio of stream circumference to disturbance wavelength. It is suggested that amplitude modulating the capillary stream’s disturbance may also decrease the diameter variation of the drops.
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47.80.-v Instrumentation and measurement methods in fluid dynamics
68.03.Fg Evaporation and condensation of liquids

Adjustable speed and vibration‐free hydraulic system for Langmuir–Blodgett films deposition

G. Munger, L. Lorrain, G. Gagné, and R. M. Leblanc

Rev. Sci. Instrum. 58, 285 (1987); http://dx.doi.org/10.1063/1.1139323 (4 pages) | Cited 7 times

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Conventional apparatus for the dipping and raising of slides usually uses an electric motor with the slides fixed in a rigid holder. Most of the devices create a great deal of vibrations and this produces a nonuniform film deposition. We have used a new apparatus, which does not produce any vibrations of the slide, to build up Langmuir–Blodgett films. To move the slide, we employ a column of water and use the siphon principle, with speeds that can be varied between 3.0 and 120.0 mm min−1. An electronic circuit controls the automatic dipping and raising of the slide. A relay switches the solenoid valve to move the piston in the opposite direction. A machined Teflon trough and antivibration mount are used for the monolayer preparation. With this method, the deposition ratio usually obtained for the cadmium arachidate and chlorophyll a is 1.00±0.05. The absorption spectrum of multilayers of chlorophyll a give a linear relation between the absorbance at 680 nm and the number of layers up to 10. The nonlinear relation for the number of layers higher than 10 is explained by the presence of aggregates.
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06.60.Ei Sample preparation (including design of sample holders)
81.10.-h Methods of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Retrievable UHV effusion cell for investigation of low melting point metals on solid surfaces

T. Castro and R. Reifenberger

Rev. Sci. Instrum. 58, 289 (1987); http://dx.doi.org/10.1063/1.1139272 (4 pages) | Cited 2 times

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The design and performance of an effusion cell used to deposit low melting point metals under UHV conditions is described. A novel feature of the cell is a transfer rod and pretreatment chamber that allow for the rapid loading and retrieval of crucibles containing low melting point source elements. This feature of our cell makes it ideal for depositing the highly reactive alkali metals. The performance of the effusion cell is evaluated for the deposition of the metal potassium.
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81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
07.30.Hd Vacuum testing methods; leak detectors
06.60.Ei Sample preparation (including design of sample holders)

Helium‐filled proportional counter for low‐temperature operation (4.2–300 K) and its application to cryogenic resonance‐electron Mössbauer spectroscopy

Yasuhito Isozumi, Shunji Kishimoto, Rintaro Katano, and Hidekuni Takekoshi

Rev. Sci. Instrum. 58, 293 (1987); http://dx.doi.org/10.1063/1.1139273 (6 pages) | Cited 16 times

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The operation of a proportional counter filled with helium gas has been investigated at low temperatures down to 5 K. It has been found for the first time that a helium‐filled counter cooled at temperatures below 30 K works well in the proportional region, but with low gas gains (≤100). The operation at low temperatures (≤30 K) is attributed to the complete removal of impurities from helium gas as well as the extreme depression of the reaction frequency of metastable heliums. The absence of impurities results in eliminating the Penning effect, i.e., an ionization process of impurity atoms or molecules by collisions with metastable helium, which spreads electron avalanches in both space and time if helium gas contains a slight amount of impurities (1–103 ppm). Continuous discharges caused by the photoeffect of ultraviolet photons, which are mostly produced in decay channels of metastable helium, are thermally quenched at low temperatures below 30 K. The helium‐filled counter provides us with a new method to detect nuclear radiations at very low temperatures. The present counter technique has been successfully applied to the resonance‐electron Mössbauer spectroscopy near liquid‐helium temperature (∼5 K).
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29.40.Cs Gas-filled counters: ionization chambers, proportional, and avalanche counters
07.85.-m X- and γ-ray instruments
76.80.+y Mössbauer effect; other γ-ray spectroscopy
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