bluuebunny/crossref_metadata_2025 huggingface dataset:
Automatic operation of a superconducting magnetic susceptibility instrument for biological samples
Authors: Owen Charles S. , Nadler Wolfgang
Published: March 2003

A commercial superconducting SQUID-based instrument for the measurement of magnetic susceptibility has been interfaced to a programmable desktop calculator for the automatic measurment of the temperature dependence of the sample magnetization M. Under program control the temperature is altered by an amount ΔT and the magnetization is monitored. When a stable reading for M indicates that the sample has reached thermal equilibrium, the change in magnetization, ΔM, is recorded and a new temperature is set. After data acquisition, the average values of ΔM for each ΔT are summed to give the temperature-dependent paramagnetism M (T) and plotted on an associated plotter.
Application of a superconducting susceptometer to biological samples
Authors: Owen C. S. , Jaffe E. K. , Wilson D. F.
Published: March 2003

A commercially available superconducting instrument for measurments of magnetic susceptibility has been applied to low-temperature measurements on frozen aqueous samples of biological interest. The performance of the instrument is discussed and procedures are described for calibration of the instrument using aqueous standard solutions in the same sample tubes that are used for unknown samples.
Method for accumulating high-resolution optical spectra by repetitive photoelectric scanning
Authors: Fülöp G. F. , O Chun-Sing , Stroke H. H.
Published: March 2003

We describe a variable speed (20–1000 μm/s) photoelectric scanning method for high-resolution optical spectra. The particular feature of our method is that we use an optical linear encoder and store the data from multiple scans in a multichannel analyzer. This results in significant improvement in signal-to-noise over single scans. Although commerically available vidicon tubes or image dissectors have the advantage of simultaneously recording the complete spectrum, our system has the advantage of high positional repeatability (1 μm) and is consequently suitable for high-resolution spectroscopy.
Performance of a spiralled continuous electron multiplier in a magnetic field
Authors: Chenevert Thomas L. , Zitzewitz Paul W.
Published: March 2003

The gain and detection efficiency of a spiralled electron multiplier (Spiraltron) have been measured in a magnetic field. Results are presented as a function of field strength and angle between the field and detector. The multiplier is useful in fields as high as 900 G, considerably higher than the limit that has been obtained on a Channeltron curved electron multiplier.
Instrumental sensitivity in soft x-ray appearance potential spectroscopy
Authors: Lee R. N.
Published: March 2003

The signal-to-noise performance of SXAPS instruments is analyzed. It is found that energy detectors are intrinsically superior to quantum detectors in SXAPS. The use of an aluminum filter with a quantum detector improves its signal-to-noise in the energy range just below the aluminum K absorption edge but does not bring its performance up to the level of an unfiltered energy detector. The use of x-ray filtration with an energy detector does not improve its performance at any energy and seriously degrades performance in regions of low filter transmission. Both types of detector have a greater sensitivity to the bremsstrahlung background than to the appearance potential structure of interest.
Study of seal tightness under pressure
Authors: Paureau J.
Published: March 2003

The equation of plastic flow of high-pressure metal-plated seals on conical plugs is established and verified experimentally in the 10 kilobar range. The mechanism of tightness is analyzed and the condition of tightness is established with the help of the equation of the plastic flow of seals. Cases are considered in which plastic flow is controlled either by the friction of the seals on the bearing surfaces, or by the conicity of the plug. It is shown that the work hardening of plated metals in the first case, and base metals in the second, may seriously limit the performances of the seals. For cells equipped with biconical plugs, in which plastic flow is controlled by both friction and the conicity of the plugs, it is concluded that base and plating materials must exhibit the smallest strain hardening rates possible. For such devices, it is emphazised that the maximum pressure to be reached is equal to two or three times the tensile strength of the base materials. It is shown that seals plated with soft metals (In, Pb) have to be used for low-temperatures applications. A review of most common metals which could be used as base and plating metals is given.
Device for automatic thermal conductivity measurements
Authors: Julia Y. H. , Renaud J. F. , Ferrand D. J. , Malbrunot P. F.
Published: March 2003

The present measurement techniques, adapted to the transient hot-wire method for absolute thermal conductivity determination, allow the realization of a simple apparatus giving automatically precise digital data. It can be connected to a printer or, better, to a computer unit. This device has been tested with a liquid cell and satisfactory agreement with published values was obtained.
Fast-dump reactor: An apparatus to study coal dissolution at short reaction times
Authors: Alkidas A. C. , Plett E. G. , Summerfield M.
Published: March 2003

A new design for a reactor is described for studying the dissolution of coal in organic solvents at short reaction times. This reactor utilizes a gas pressure forced injection system to permit rapid injection, and a movable reaction chamber floor to allow the discharge of the reactants for rapid quenching. Dissolution studies have been performed at reaction temperatures of up 470 °C and pressures of up to 115 atm. Quenching times of the reactants of the order of 1 sec are achieved routinely. Typical results are presented to show the versatility of the apparatus.
High performance SIMS system
Authors: Dawson P. H. , Redhead P. A.
Published: March 2003

The performance of a high-sensitivity secondary ion mass spectrometer is described. The spectrometer is used for studies of gas–surface interactions and operates under ultrahigh vacuum conditions with a mass-analyzed primary beam of low energy. The secondary ion detection system incorporates a retardation/acceleration energy analyzer with a large acceptance angle and a central stop which improves the signal/noise ratio. The analyzer emittance was designed to match the acceptance of a quadrupole mass filter. A calibration procedure is used to correct for the velocity discrimination of the quadrupole mass analyzer. Some applications to SIMS and to electron-induced desorption are illustrated.
Optically isolated high-voltage trigger system
Authors: Henins Ivars , Kelly Michael S.
Published: March 2003

An optically isolated high-voltage trigger system has been built to eliminate ground loop and electromagnetic interference problems in the triggering of a pulsed high-voltage plasma experiment. In this system fast-rising light pulses are generated at the trigger source and transmitted through 20 m long glass fiber optics cables to detectors, which trigger 7-kV pulsers used to drive high-voltage spark gap switches. The 7-kV pulsers are battery powered and may be floated to the potentials existing on the spark gaps.
Source for negative halogen ions
Authors: Kashihira N. , Vietzke E. , Zellermann G.
Published: March 2003

A simple and inexpensive ion source has been developed for collision dynamic studies. The negative halogen ions are produced by negative surface ionization at a hot surface of LaB6. Because of the selectivity of this ionization process mass selection is not necessary. Emission densities of 10−4 A/cm2 at an energy spread of 0.55 eV are obtained.
Passive image dissector for time-resolved ir spectroscopy
Authors: Baldis H. A. , Burnett N. H. , Richardson M. C.
Published: March 2003

A passive image dissection technique is described which is capable of switching adjustable slices of a linear ir image onto a single-element detector with a fixed time delay between successive samples. The device allows good spatial resolution with state-of-the-art detectivity and temporal resolution. The dissector has been employed in combination with a grating spectrograph to study the spectrum of backscattered radiation from CO2 laser-produced plasmas, with 25 spectral channels and grating-limited spectral channel width.
In vivo extensometer for measurement of the biomechanical properties of human skin
Authors: Thacker J. G. , Iachetta F. A. , Allaire P. E. , Edgerton M. T. , Rodeheaver G. T. , Edlich R. F.
Published: March 2003

A skin extensometer has been developed to provide in vivo quasistatic elastic measurements of human skin. The instrument incorporates two double-cantilevered beams to produce uniaxial loads on the skin. The device provides clinical information that aids the surgeon in the design of incisions and excisions.
Simplified apparatus for detecting solid state transformations by ac induction at elevated temperatures
Authors: Valenzuela Javier , Miller A. E.
Published: March 2003

An apparatus for detecting solid state phase transformations in the 30–1200 °C temperature range has been designed and constructed. In this simple but sensitive apparatus, detection is based on the changes in magnetic permeability and/or electrical resistivity accompanying the solid state reaction.
Photomultiplier power supply using high-frequency transmission
Authors: Gonda Tsunemi , Kimoto Kiyoshi
Published: March 2003

A very stable power supply for a photomultiplier is described that uses high frequency to transmit the error signal.
Simple system using one-crystal composite oscillator for internal friction and modulus measurements
Authors: Schwarz R. B.
Published: March 2003

The three-component composite oscillator, which has separate drive and detect transducers, is widely used in internal friction experiments for obtaining simultaneous decrement, modulus, and strain amplitude measurements. Some disadvantages of this system for measurements at low temperatures are discussed. A new system is described that uses a single-quartz composite resonator as part of the feedback loop in a simple electrical oscillator circuit. This method provides accurate measurements and is far simpler than many of the systems previously proposed. It offers definite advantages for applications at low temperatures or when the sample has to be located inside a reactor facility.
Technique for producing ultrathin polypropylene films
Authors: Barrus D. M. , Blake R. L.
Published: March 2003

A method is described for stretching commercially available polypropylene film to thicknesses in the range 0.2–1.0 μm. Such films are used as windows for soft x-ray proportional counters, gas absorption cells, energy-loss nuclear detectors, and high vacuum isolation.
Circulated-liquid calorimeter for the detection of high-power and high-energy pulsed laser signals
Authors: Fisk G. A. , Gusinow M. A.
Published: March 2003

The design, construction, calibration, and testing of a circulated-liquid volume absorption calorimeter are described. The device is designed to operate at input irradiance/energy combinations at which surface absorption calorimeters are damaged. It has been tested with pulsed laser signals at the several-hundred-joule input level at two widely separated wavelengths and should function well at the multikilojoule level.
High energy ion analyzer for laser-produced plasma studies
Authors: Decoste R. , Ripin B. H.
Published: March 2003

A simple electrostatic-deflection multichannel time-of-flight ion analyzer optimized to study high energy ion species from laser-produced plasmas is described. For this application moderate species and energy resolution over a wide dynamic energy range is desirable. The analyzer was designed to achieve a dynamic energy range from 1 to 1000 keV with a 15 kV power supply. Design considerations are presented together with some typical experimental results.
Transient capacitance deep level spectrometry instrumentation
Authors: Miller M. D. , Patterson D. R.
Published: March 2003

Instrumentation is described which allows rapid, sensitive survey measurements of deep impurities in semiconductors by monitoring the temperature dependence of the capacitance transient arising from pulsed reverse bias of a p–n junction or Schottky barrier.
Baseline corrector for boxcar integrator instruments and its application to plasma chromatography
Authors: Lawless P. A. , Spangler G. E.
Published: March 2003

A circuit is described for correcting the baseline drift of boxcar integrator instruments, specifically a plasma chromatograph. The circuit is divided into three parts: timing, modulation, an demodulation. The timing circuit derives a trigger pulse and a low-frequency modulation pulse from the power line frequency. The modulation circuit imposes external gate-time determination on the internal timing of the plasma chromatograph. The demodulation circuit uses voltage-to-frequency conversion and multichannel scaling. The technique is general and useful for other drifting baseline situations.
Technique for producing uniform charged drops of cryogenic liquids
Authors: Woosley J. P. , Turnbull R. J.
Published: March 2003

We have investigated and developed a reliable method to produce uniformly charged liquid nitrogen drops. An apparatus has been built which is capable of producing and charging drops in the 200 μ diameter range. Rayleigh’s method of uniform droplet production, which consists of breaking up a smooth liquid jet into uniform drops by an acoustic wave, is used. The diameter of the drops is controlled by the inside diameter of the nozzle and the frequency of the acoustic wave. Charges injected into the jet through field emission or field ionization subsequently end up on the drops, thereby producing uniformly charged drops. The charge per drop is determined by the amount of charge injected into the jet and by the number of drops produced per second. The maximum charge which could be placed on a single drop without impairing its integrity was one-fifth of its Rayleigh limit. The method described here could be applied to other insulating cryogenic liquids such as liquid hydrogen.
Chemically enhanced opening switch for generating high-voltage pulses
Authors: Friedman M. , Ury M.
Published: March 2003

A new approach to the problem of developing an opening switch is described. The switch (fuse) consists of an aluminum foil immersed in water. Heat transfer processes and chemical reactions between the Al and water determine switch performance. Six kilojoules of electrical energy were handled by the switch, and voltages of up to 100 kV were generated across the switch electrodes.
X-ray streak camera for observation of tightly pinched relativistic electron beams
Authors: Johnson David J.
Published: March 2003

A pinhole camera is coupled with a Pilot-B scintillator and image-intensified TRW streak camera to study pinched electron beam profiles via observation of anode target bremsstrahlung. Streak intensification is achieved with an EMI image intensifier operated at a gain of up to 106 which allows optimizing the pinhole configuration so that resolution is simultaneously limited by photon-counting statistics and pinhole geometry. The pinhole used is one-dimensional and is fabricated by inserting uranium shims with hyperbolic curved edges between two 5-cm-thick lead blocks. The loss of spatial resolution due to the x-ray transmission through the perimeter of the pinhole is calculated and a streak photograph of a Gamble I pinched beam interacting with a brass anode is presented.
Electromechanical high-pressure torsion apparatus
Authors: Pae K. D. , Silano A. A.
Published: March 2003

An apparatus for carrying out torsional shear tests of polymers under hydrostatic pressure environment at variable rotational speeds has been developed and tested. The apparatus is capable of containing pressures up to 7 kilobars and producing rotational speeds to 1000 rpm. A number of important and unique features have been incorporated into the design of the apparatus. The apparatus consists of two interconnected thick-walled cylinders, one for testing and the other for pressure compensation. The rotation rate is automatically maintained at a constant level throughout a test by a feedback amplifier circuit. The magnitude of the applied torque is detected by a load cell mounted within the torque shaft, unexposed to the pressure medium and unaffected by the friction in the seals. The angular displacement is sensed both internally and externally, respectively, by an electrically activated contact point moving over a toothed wheel mounted on the rotating end of the specimen and by a rotary variable differential transformer (RVDT). The signals from the torsion cell, the rotary contact point, and the RVDT are monitored and recorded by an integrated electronic system. The shear stress–strain diagrams of a polymer, polypropylene (PP), have been obtained at various pressures. The data show the dependence of elastic and plastic behaviors of PP on hydrostatic pressure.
Adaptation of an ion microprobe for ion bombardment of liquid metals
Authors: Fischer Albert K. , Steidl David V. , Johnson Carl E.
Published: March 2003

A technique involving a new substage assembly was developed to permit an ion microprobe mass analyzer (IMMA) to be used as an ion bombardment facility for molten metals (lithium) without harm to the instrument from the hot, reactive samples.
Time-of-flight velocity selection using pulsed tunable laser fluorescence detection
Authors: Pasternack Louise , Dagdigian Paul J.
Published: March 2003

A time-of-flight velocity selection method utilizing pulsed tunable laser fluorescence detection is described. The flight time is determined by the delay between the time when a pulse of particles is let through a chopper slit and when a pulsed dye laser is fired. The method is illustrated by velocity analyses of the Na thermal decomposition product in a NaCl beam and of a Ca atomic beam.
FET Q switch for pulsed NMR
Authors: Conradi Mark S.
Published: March 2003

A Q switch which shortens the ringing time in pulsed NMR equipment is described. It uses a field-effect transistor as the Q-switching element. A convenient method of generating the control signal is shown. The device performs well and is simple to construct and adjust.
Spectrograph suitable for the mass and energy analysis of space plasmas over the energy range 0.1–10 keV
Authors: Moore T. E.
Published: March 2003

The design and performance of a small, high resolution ion mass–energy spectrograph are described. By utilizing a second-order double-focusing field geometry, mass resolution sufficient to separate energetic space plasma ions such as C+, N+, and O+ has been achieved. The instrument responds to ions over a wide range of parameters (0.1–10 keV, 1–200 amu) and has a sufficient sensitivity for rocket or satellite measurements of space plasma ion populations (geometric factor ∼10−4E0 cm2 sr keV). Sample mass spectra are displayed to show the laboratory prototype’s response to artificially generated beams containing a variety of energetic ions. Plans for future development are briefly discussed.
Calibration of marginal oscillator sensitivity for use in ICR spectrometry
Authors: Anicich V. G. , Huntress W. T.
Published: March 2003

A new design of a Q-spoiler, a constant reference load, is introduced and evaluated. The device is useful in the calibration of a marginal oscillator’s relative sensitivity variations with frequency. In a capacitive divider design, the loading of the marginal oscillator with respect to frequency is largely dependent on the choice of components. The new design uses a large resistance and compensates for the resistor’s capacitance by switching between the resistor and another leg of the circuit that has a matched capacitance.
Compact TEA N2 laser
Authors: Bergmann Ernest E.
Published: March 2003

A novel pulsed uv laser that operates with pure N2 at 1 atm pressure is described. The length of the laser channel is only 25 cm, yet the laser is capable of producing over 0.5 MW peak power with less than 20 kV supplied to the circuit. Its simple construction should encourage widespread duplication.
Automatic screw identification using spatial filtering
Authors: Indebetouw G.
Published: March 2003

A simple optical probe is described which enables one to control in real time the parameters (length and thread caliber) of screws entering an automatic assembly line. The information needed for the identification of a type of screw is extracted from the image and the optical spatial spectrum of the screw with the aid of simple binary masks.
The Photicon
Authors: Kellogg E. , Murray S. , Briel U. , Bardas D.
Published: March 2003

We report on the performance of a new type of imaging optical detector which we call the Photicon. It uses a conventional semitransparent photocathode, imaging electrostatic optics, microchannel plates, and a crossed wire grid position-sensitive charge detector. Single photon events produce a digital word giving the position of the event. An image can be accumulated in a memory array, or stored serially with each event’s time of occurrence recorded with 10−6-sec precision. Spatial resolution of σ≃20 μm has been achieved so far in a 25-mm-diam active area detector.
Optical isolation operational amplifier
Authors: Chou N. J. , Castellano A.
Published: March 2003

The paper describes an optical isolation operational amplifier designed to measure electrical current in the 10−11–10−6 A range at ±1000 V.
Device for pure shear deformation of single crystals
Authors: von Alpen U. , Doukhan J. C.
Published: March 2003

c glide in tellurium single crystals cannot be studied by conventional uniaxial tests because slip on other glide systems cannot be suppressed, and because these systems are also active. We have developed a shearing device which allows this study to be performed. This attachment and the first results are described. The device can be used for problems such as the study of cross slip mechanisms, because it forces the deformation to occur in a given glide plane.
Auto-increment circuit for a digital pulse programmer
Authors: Adduci D. J. , Hornung P. A. , Torgeson D. R.
Published: March 2003

A circuit is described which will automatically advance the time spacings between groups of pulses of a digital pulse programmer controlling a pulse nuclear magnetic resonance spectrometer. The automatically incremented spacings of the pulse groups is particularly useful in spin-lattice relaxation time measurements in either a single-passage analog recording of transient signal information or multiple-passage digital (signal-averaging) recordings. Circuitry for operation in these two modes is presented. This auto-increment circuitry has been used in conjunction with the digital pulse programmer described by Conway and Cotts (preceding paper).
Use of precise binary diffusion coefficients to calibrate two-bulb cells instead of using the standard end correction for the connecting tube
Authors: Arora P. S. , Shankland Ian R. , Bell T. N. , Yabsley M. A. , Dunlop Peter J.
Published: March 2003

Precise binary diffusion coefficients, 𝒟12, at 300 K have been used to show that the end correction which is normally applied to the connecting tubes of two-bulb cells is not precise enough when an accuracy of 0.1% in 𝒟12 is required. However, two-bulb cells may be calibrated with the standard diffusion coefficients reported in this paper.
Ionizer for cluster ion accelerators
Authors: Henkes Wolfgang , Hoffman Volker , Mikosch Falk
Published: March 2003

The design and performance of a cluster ionizer of the Bayard–Alpert type which is intended to be used in cluster accelerators is described. Positive cluster ions are formed from neutral hydrogen clusters with an efficiency of up to 80%. The mean size of clusters can be reduced by an order of magnitude by multiple ionization followed by splitting into charged fragments due to the repulsion between the individual charges. The fraction of the electrical current carried by cluster ions exceeds 90% of the total ion current. At low particle density two modes of operation are found. The ’’normal’’ mode A with high efficiency is characterized by space charge compensation of the primary electrons. In mode B this compensation is missing and the efficiency drops to less than 20% of that of mode A.
System for automatically tracking white blood cells
Authors: Greene F. M. , Barnes Frank S.
Published: March 2003

An instrument is described that enables a high-power, phase contrast microscope to automatically follow the movements of individual white blood cells in vitro. The system also generates a recording of the cells’ movement over a period of up to several hours.
Reduction of polarizing radiometer data
Authors: Walraven Robert L.
Published: March 2003

Excellent agreement with data taken with a polarizing radiometer is obtained when the data are fit with a form containing constant, first harmonic, second harmonic, and slope terms. The data may be reduced rapidly by a single matrix multiplication using a technique described in this article.
Inexpensive recording thermometer
Authors: Jackman A. P. , Noble R. D. , Bonouvrie H. J.
Published: March 2003

Monitoring of water temperature is widespread, due to its importance as a water quality parameter. This paper describes a simple, accurate, and inexpensive recording temperature monitor based on a thermistor temperature sensor. A special resistance bridge circuit is incorporated whose output is extremely linear with temperature. The output of the bridge network is converted to a frequency signal which can be recorded on an inexpensive cassette recorder. The entire system, capable of recording up to 9 days’ data, is powered by two 6-V lead–acid motorcycle batteries.
Focusing properties of an anode-controlled telefocus keV electron gun
Authors: Schiewe B. , Schmoranzer H. , Wollenweber P.
Published: March 2003

A new design of a triode telefocus keV electron gun is presented, of which the focal distance can be varied during operation of the gun by axially adjusting the anode. The dependence of the maximum beam current density on geometrical and electrical quantities has been investigated in the neighborhood of the beam crossover, yielding the basic data for optimizing the gun performance under given experimental boundary conditions. At a crossover distance of 0.27 m a beam width (FWHM) of 65 μm corresponding to a current density of 3.1×104 A m−2 was attained at an acceleration voltage of 17.5 kV.
Method for ensuring comparable temperatures in biological experiments using multiple incubators
Authors: Greenebaum B. , Marron M. T. , Goodman E. M.
Published: March 2003

We describe a method for overcoming the tendency of four separately controlled incubators to drift apart in temperature. One incubator acts as a master temperature control; the control circuits of the others sense and eliminate temperature differences between the master and the other incubators.
Thermoelectric power measurements using analog subtraction
Authors: Eklund P. C. , Mabatah A. K.
Published: March 2003

A simple, inexpensive analog subtraction circuit for measuring the Seebeck coefficient of semiconductors as a function of temperature is described. The circuit and an X-Y plotter are the only electronics needed to acquire the data. An accuracy of better than 1% can be achieved.
Small-volume, inclined, falling-ball viscometer
Authors: Geils R. H. , Keezer R. C.
Published: March 2003

A simple viscometry technique is described, suitable for use at high temperature and/or pressure. A typical viscometer consists merely of a short sealed metal or glass tube containing the sample and an appropriate ball. A simple analysis of the problem is given for Newtonian fluids and the unknown constants fitted experimentally so that absolute viscosities can be obtained. The technique has been used successfully on liquid volumes of 6 cm3 above 1000°C, the limit being set by the vapor pressure which the ampoule could withstand.
Simply actuated closure for a pressure vessel: design for use to trap deep-sea animals
Authors: Yayanos A. Aristides
Published: March 2003

A pressure vessel is described that can be closed by a single translational motion within 1 sec. The vessel is a key component of a trap for small marine animals and operates automatically on the sea floor. As the vessel descends to the sea floor, it is subjected both internally and externally to the high pressures of the deep sea. The mechanism for closing the pressure vessel on the sea floor is activated by the timed release of the ballast which was used to sink the trap. As it rises to the sea surface, the internal pressure of the vessel remains near the value present on the sea floor. The pressure vessel has been used in simulated ocean deployments and in the deep ocean (9500 m) with a 75%–85% retention of the deep-sea pressure. Nearly 100% retention of pressure can be achieved by using an accumulator filled with a gas.
Wide-band optical–mechanical system for measuring acoustic emissions at high temperature and pressure
Authors: Blacic J. D. , Hagman R. L.
Published: March 2003

We have designed an optical–mechanical system for measuring acoustic emissions at high temperature and pressure over the frequency range dc–4 MHz. This is accomplished by measuring with a laser interferometer the strain of an elastic column on which the test sample rests and which is contained within the pressurized volume. Interferometer fringe motion is detected and, by means of quadrature logic, converted to a linear analog signal proportional to stress on a test sample.
Simple single-coil double resonance NMR probe for solid state studies
Authors: Stoll M. E. , Vega A. J. , Vaughan R. W.
Published: March 2003

A single-coil (solenoid), nuclear magnetic double resonance sample probe, suited for a wide variety of solid state studies, is described. It was designed to be used in double resonance experiments where it is necessary to generate intense rf magnetic fields (rotating components with amplitudes ∼50 G) at two widely spaced frequencies and simultaneously to detect microvolt-level signals. Designs for operation over the 12–270 MHz frequency range are discussed.
Iodine laser energy profile measurments at 1.315 μm by using hypersensitized photographic plates
Authors: Farcy J. C. , Beaupere D.
Published: March 2003

It is demonstrated that type IZ hypersensitized photographic plates can be efficiently used at 1.315 μm. This method is used and discussed to characterize a single transverse mode iodine oscillator.
Versatile grazing incidence spectromonochromator for the xuv region
Authors: Jaeglé P. , Dhez P. , Wuilleumier F.
Published: March 2003

A new type of grazing incidence spectromonochromator, which can serve equally the need of synchrotron radiation research and plasma research, is presented. Making use of the Rowland circle mounting, it is based on the two-grating principle that proved to be very efficient in separating higher orders in a previous prototype. A new mechanical system, well adapted to the current possible uses, has been incorporated. The apparatus can work as a spectrograph or as a monochromator, with one or two gratings, with a mobile or a fixed exit slit. In the spectrograph mode it can be used either with a photographic chamber or with a photoelectric detector. The incidence angle on each grating can be varied continuously and the gratings can be easily changed and readjusted entirely with visible light. The adaptation of the apparatus to the synchrotron radiation emitted by the ACO storage ring is described and the first results of tests, concerning mainly its order-sorting capability, its resolution, and the absolute flux of photons available, are presented.
In-cavity hot cell for use with sequence CO2 lasers
Authors: Berger W. , Siemsen K. , Reid J.
Published: March 2003

A technique is described for approximately doubling the number of laser lines obtainable from cw CO2 lasers. This technique involves the use of an in-cavity cell containing hot CO2. Construction details are given of a suitable cell which attains gas temperatures as high as 500° C.
Generator of droplet tracers for holographic flow visualization in water tunnels
Authors: Charwat A. F.
Published: March 2003

This paper describes the design and performance of a drop generator intended for use in generating near-neutrally buoyant liquid tracers for holographic visualization of complex flows in water tunnels.
Effect of emission aperture shape upon ion optics
Authors: Grisham L. R. , Tsai C. C. , Whealton J. H. , Stirling W. L.
Published: March 2003

Several different axisymmetric aperture shapes have been studied, experimentally and theoretically, for use in the plasma electrode employed in extracting ions from a plasma. Compared to a cylindrical bore aperture, a class of shapes opening away from the source plasma resulted in smaller beam divergence (due to reduced aberration fields), while a class opening toward the source plasma resulted in higher beam power density at optimum divergence. The minimum half-width-half-maximum divergence obtained for the former class was 0.57° at a beam energy of 27 kV, as compared to 1° obtained for a conventional cylindrical bore aperture.
Differential calorimeter for measurement of absorbed energy in laser-produced plasmas
Authors: Pelah Israel , Hauer Allan
Published: March 2003

Accurate estimates of the amount of optical energy absorbed by a target are an important diagnostic of laser-induced fusion experiments. Measurements of the total energy blown off of a target in the form of charged particles is one method of evaluating the percentage of optical absorption. We have developed a special calorimetric device that is suitable for the measurements of the total flux of both charged particles and x rays. These devices provide high sensitivity to ions and x rays while maintaining good discrimination against scattered light.
Simple waveguide reflection maser with broad tunability
Authors: Flesner Larry D. , Schultz Sheldon , Clauss Robert
Published: March 2003

The design and performance of a simple two-stage reflection maser for use between 9 and 10 GHz are described. The maser is used to improve the sensitivity of a transmission electron spin resonance spectrometer. A ruby-filled waveguide structure permits broad tunability and straightforward construction. All microwave components except the ruby section are at room temperature.
Temperature measurement error due to the effects of time varying magnetic fields on thermocouples with ferromagnetic thermoelements
Authors: McDonald D. W.
Published: March 2003

Thermocouples with ferromagnetic thermoelements (iron, Alumel, Nisil) are used extensively in industry. We have observed the generation of voltage spikes within ferromagnetic wires when the wires are placed in an alternating magnetic field. This effect has implications for thermocouple thermometry, where it was first observed. For example, the voltage generated by this phenomenon will contaminate the thermocouple thermal emf, resulting in temperature measurement error.
On-line display aids for the automated measuring of bubble chamber film at Fermilab energies
Authors: Jacques P. F. , Badiak R. , Ou T. C. , Plano R. J. , Sanders H. , Stamer P. E. , Watts T. L.
Published: March 2003

An operator uses a new video display with separately adjustable magnifications along the x and y axes to assist the measuring of Fermilab 76.2-cm bubble chamber film by our computer controlled measuring device (PEPR). The differential magnification enlarges angles and curvatures of the many fast-forward tracks present in events of energy 100 GeV or greater. The display is used by the PEPR operator to view complicated events and guide the computer track measurement and to make manual measurements of obscured tracks which are too difficult for the automatic system to handle. We present results on 2900 events containing neutral strange particles and gamma conversions in π− p collisions at 147 GeV/c.
Production of H-atom and O-atom beams by a cooled microwave discharge source
Authors: Ding A. , Karlau J. , Weise J.
Published: March 2003

A beam of hydrogen and oxygen atoms in the thermal energy range was produced by microwave discharge. The microwave apparatus was used inside a vacuum chamber and therefore required a cooling system. We observed a typical dissociation efficiency of 0.63 from the hydrogen discharge and of 0.73 from a mixture of hydrogen and argon. After coating with concentrated ortho-phosphoric acid, a hydrogen dissociation efficiency as high as 0.82 could be observed. The fraction of dissociated oxygen molecules was measured to be 0.33.
Erosion rate measurements using an acoustic technique
Authors: Sutherland H. J. , Kent L. A.
Published: March 2003

An acoustic technique, based on a pulse–echo ultrasonic method, is used to monitor, as a function of time, the relative position of an interface between two materials. The instrumentation and the techniques for its use are discussed. The technique is illustrated by monitoring the movement of an ice–flame interface and a concrete–plasma interface.
Magnetic field modulation technique for the study of hot carrier oscillatory magnetoresistance phenomena
Authors: Kahlert H. , Seiler D. G.
Published: March 2003

A new experimental technique is reported which allows the detection of the oscillatory components of the magnetoresistance of semiconductors subject to high electric fields, where the pulse length must be in the submicrosecond region in order to avoid lattice heating. It uses a combination of sampling and magnetic field modulation techniques. Its capability of resolving hot-electron magnetophonon structure in n–InSb at 77 and 4.2 K for up to N=10 Landau level spacings is demonstrated.
Control system for the analytical processing of stereo images
Authors: Real R. R. , Lau K. K.
Published: March 2003

Control aspects of a precision computer controlled stereoscope and plotter built for analytically studying stereo images are described. A discussion of stereo correlation and instrument response precedes details of the control computer and servo system. In conclusion, there is a short description of some of the devices that can be used with the instrument as an aid to data reduction from stereo imagery.
Determination of magnetic domain structure by Fraunhofer diffraction
Authors: Ruf Ralph R. , Gambino R. J.
Published: March 2003

Ferrofluid decorated magnetic domain patterns diffract light like a diffraction grating. The resulting patterns are influenced by the size and structure of the individual domains providing a convenient measure of these properties.
Photo-acoustic spectroscopy of solids
Authors: Rosencwaig Allan
Published: March 2003

A method is presented by which photo-acoustic spectroscopy of solids may be performed. Criteria for the light sources, sample chambers, and data acquisition systems are discussed. The dependence of the photo-acoustic signal on various experimental parameters is explored, and some of the applications of this new technique are discussed.
Current regulated sweep unit for superconducting solenoids
Authors: Everett P. M.
Published: March 2003

A circuit is presented that controls a voltage programmable power supply and causes the current through a superconducting solenoid to vary either inversely or linearly with time. The circuit regulates the solenoid current and allows for a finite portion of the power supply current to shunt the solenoid.
Cotton fiber specimen clamps for x-ray angle—tensile measurements
Authors: Krowicki R. S. , Worley S. , Elliott P. W.
Published: March 2003

The specifications for clamps which can be used to obtain the x-ray angle and tensile measurements of the same specimen of cotton fibers are presented. The tenacity of flat bundles of cotton fibers when these clamps are used is compared with that when Pressley clamps are used.
Modified technique for dynamic surface pressure and relaxation measurements at the air–water interface
Authors: Tabak S. A. , Notter R. H.
Published: March 2003

A modified Wilhelmy surface balance design is presented which permits the use of both ’’dam’’ and ’’ribbon’’ compression barriers in the measurement of surface pressure behavior. Both kinds of barrier are interchangeable in a single-surface balance trough, and this allows utilization of the strong points of each. Both barrier designs give rise to a linear surface area change upon compression, although the recessed dam barrier results in a more regularly shaped surface. The ribbon barrier, on the other hand, gives a completely contained surface free from barrier leakage artifacts. The utility of both barrier designs is demonstrated by dynamic surface pressure–area (π-A) and relaxation experiments on dipalmitoyl lecithin (DPL) monolayers at 23 and 37 °C. The dual barrier design is shown to optimize the potential for the unambiguous interpretation of dynamic surface pressure measurements for this highly important component of pulmonary surfactant.
Modification of a commercial admittance bridge to measure large conductances
Authors: Berberian John G.
Published: March 2003

The modification of the commercial General Radio 1615 admittance bridge to measure high conductances is presented in detail. The restriction of limited phase angle at constant resolution in either component of admittance is removed by this modification. In addition to increasing the conductance range by a factor of 100 over the original specification, the conductance circuitry has been arranged to permit a ten-to-one internal comparison between the conductance standards. When the voltage scaling transformer is used, a maximum conductance of 11.11 mmho can be measured at somewhat reduced accuracy. Design criteria for the conductance unit’s construction are presented. The usable frequency of the instrument is extended from 10 to 100 kHz, and data reflecting the accuracy of measurements of conductances are presented.
Comment on the equivalent noise bandwidth approximation
Authors: Kittel Peter
Published: March 2003

There is an ambiguity when the equivalent noise bandwidth (ENBW) is used to calculate the response to noise of an ac voltmeter. This difficulty can be overcome by a more complete definition of the ENBW.
Air-lock system for the transfer of reactive samples to the Philips EM 300S electron microscope
Authors: Solliard C. , Rappaz M.
Published: March 2003

An air-look system has been developed in order to transfer reactive samples under vacuum from any preparation facility to the high-resolution stage of the Philips EM 300S electron microscope. The system has been tested using the highly hygroscopic material strontium chloride prepared in the form of small particles. Based on the shape of the particles and the associated diffraction pattern, it has been shown that the air-lock transfer system effectively prevents hydration in the case of small SrCl2 particles.
Pulsed ion cyclotron resonance mass spectrometer for studying ion–molecule reactions
Authors: McIver Robert T.
Published: March 2003

A pulsed ion cyclotron resonance mass spectrometer utilizes the cyclotron resonance principle for mass analysis of ions trapped at low pressures by electric and magnetic fields. Both mass analysis and ion trapping are accomplished in a one-region device called a trapped ion analyzer cell. A pulsing sequence is described which allows for generation of ions by electron impact, reaction with added gases, and mass analysis of the products of ion–molecule reactions. Methods are described for measuring rate constants and equilibrium constants for ion–molecule reactions. The high ion trapping efficiency and open geometry of the analyzer cell make it well suited for studying the interaction of laser radiation with gaseous ions and may also be useful for high-accuracy isotope ration mass spectrometry.
Regulator for controlling liquid helium bath near 4.2 K
Authors: Gamble T. D. , Goubau W. M. , Ketchen M. B. , Clarke J.
Published: March 2003

A simple regulator for stabilizing the temperature of a liquid 4He bath near 4.2 K is described. The device controls the pressure of the 4He gas, and achieves a stability of ±50 μK for the hold-time of the cryostat.
Study of the piston-rotation technique for piston-cylinder devices
Authors: Wolbarst A. B. , Clark J. B. , Richter P. W.
Published: March 2003

In piston-cylinder studies of reconstructive phase transitions, piston rotation plays a more subtle role than has previously been thought. Rotation of the piston not only relieves sliding friction, but also helps to activate sluggish transformations. This suggests modification of the traditionally accepted volumetric technique, and of the standard interpretation of data.
Microparticle accelerator of unique design
Authors: Vedder James F.
Published: March 2003

A microparticle accelator of unique design, which produces high-velocity, micrometer-sized projectiles of any cohesive material, is described. In the source, an electrodynamic levitator, single particles are charged by ion bombardment in high vacuum. The vertical accelerator has four drift tubes, each initially at a high negative voltage. After injection of the projectile, each tube is grounded in turn at a time determined by the voltage and charge/mass ratio to give four acceleration stages with a total voltage equivalent to about 1.7 MV. The delay times may be set manually or controlled automatically by the particle’s charge/mass ratio measured in the source by the operator just before ejection. At the entrance to the accelerator, the particle generates a signal that initiates the timing sequence. In the target chamber, detectors record the passage of the particle and provide information on charge, velocity, and position. Trajectories usually pass within a 1-mm-radius circle 1 m below the fourth drift tube. Velocities between 0.5 and 15 km/s have been attained with projectiles of various materials and shapes for cratering studies and calibration of micrometeoroid detectors. About 20 projectiles per day can be accelerated.
Optimization and performance of electrostatic particle analyzers
Authors: Jones R.
Published: March 2003

Experiment and simple theory provide a description of the performance of planar gridded electrostatic particle analyzers in magnetoplasma.
Automated apparatus for evaporation and i
n s
i
t
u measurements of multiple thin films
Authors: Clark William H. , Brient S. John , Longbrake R. L. , Graves J. Elon
Published: March 2003

We describe a system for vacuum deposition which measures as well as controls substrate temperature, film thickness, and rate of evaporation. By measuring the resonant frequency of a quartz crystal oscillator which has been calibrated for thickness, we produce films of 11 different thicknesses in a single evaporation. The system is then capable of immediately initiating four-probe resistivity measurements on the evaporated films every 90 s, allowing the measurement of rapid structural changes. The system is calculator-based and interfacing is achieved with plug-in compatible instrumentation using the IEEE standard 488-1975 interface bus.
Fast and simple photometric signal processing unit
Authors: Kriz̆an M. , Grubić M.
Published: March 2003

A simple and fast photometric signal processing unit has been constructed using some of the commonly available linear and digital integrated circuits. A common mode rejection ratio of 75 dB, based on the subtraction of the output and reference signal, and a rise time of 0.2 μs have been achieved with this instrument.
Single line CCD camera to improve positioning
Authors: Nyssen M. , Vounckx R. , Cornelis J.
Published: March 2003

This article describes an opto-electronic device that allows on-line visualization of the optical intensity function along a strip. The use of a linear optical charge-coupled device (CCD) array eliminates all moving parts. This makes adaptation to a standard microscope possible without modifications. The setup described here is essential where precise positioning of a reference graticule on diffuse lines must be performed.