bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetization and a Superconducting Solenoid
Authors: Aron Paul R.
Published: February 2005

The relationship of the magnetization of Nb-25% Zr superconducting alloy and the magnetic field of a solenoid constructed of this material is discussed. Measurements of the magnetic field as a function of current, induced magnetic moment, history-dependent remanent moment, and other related properties are described. An approximate method of computing the magnitudes of these effects is discussed and the results are shown to agree with measurements. The coil critical current Ic is related to the short sample Ic, and the discrepancy is discussed in terms of the magnetization of Nb-Zr.
Microscopic Chamber for Simultaneous Measurement of Motility and Respiration of Spermatozoa
Authors: Rikmenspoel Robert
Published: February 2005

A system is described which enables the simultaneous measurement of respiration and motility of spermatozoa. Additions can be made to the sperm suspension during the experiment. Noise and drift of the oxygen electrode are small enough to permit respiration measurements on suspensions containing (1 to 2)×107 sperm/cc.
Electronic Analyzer for Measuring Velocities and the Concentration of Spermatozoa
Authors: Rikmenspoel Robert
Published: February 2005

An electronic system is described herein which analyzes signals obtained from photoelectric measurements of bull spermatozoa. The system allows the average velocity and the concentration of the sperm to be obtained. Measurements of average velocities in the range 50 to 150 μ/sec with an accuracy of 7%, and concentration up to 3×107 cells/cc with 15% accuracy are reported.
Power Calorimetry of Fast-Particle Beams
Authors: Chambers E. S.
Published: February 2005

Equations are developed for the temperature behavior of a target struck by a particle beam. The temperature change is obtained as a function of time for given beam power, heat capacity, and conductivity. Using thermistors to measure temperature difference, a calorimetric target was developed with a sensitivity of about 5 μW. Such a detector is capable of comparing ion and neutral beams.
Internal Hydrogen Targets for Heavy Liquid Bubble Chamber
Authors: Carlino L. , Musset P. , Quéru P. , Duthil R. , Garin J. M. , Marquet M.
Published: February 2005

Insertion of a liquid hydrogen target into a heavy liquid bubble chamber combines some of the advantages of the hydrogen bubble chamber (production on free proton) with that of the heavy liquid bubble chamber (detection and measurement of neutral particles). Two different targets adapted to experiments with 8 GeV/c π− and 16 GeV/c π− are described. They have been used successfully for two experimental runs, which provided 350 000 photographs, in the École Polytechnique 1-m bubble chamber.
Description of a Device Used to Measure Ion Beam Emittance
Authors: Rose P. H. , Bastide R. P. , Brooks N. B. , Airey J. , Wittkower A. B.
Published: February 2005

The beam emittance was measured by an instrument consisting of a slowly moving sampling aperture located in front of a rapidly moving pickup wire. The position of the aperture and the difference between the position of the wire and that of the aperture were impressed upon the x and y plates, respectively, of a storage oscilloscope. Each time the pickup wire passed through the beam sampled by the aperture, a signal was produced. The width of this signal, which depended upon the convergence or divergence of the beam sampled, was used to pulse-brighten the oscilloscope. (In this way an area was plotted on the oscilloscope which was directly proportional to the beam emittance.)
Bunching of a Beam of 20-keV Neutral Hydrogen Atoms
Authors: Rose P. H. , Wittkower A. B. , Brooks N. B. , Bastide R. P. , Legros M.
Published: February 2005

A beam of 20-keV neutral hydrogen atoms was formed by electron attachment in a hydrogen gas canal. Prior to neutralization, the protons were velocity modulated by applying an accelerating voltage to the neutralizing canal, thereby requiring only a single gap to produce bunching. The flight time of the neutral atoms, between the buncher and a target, was over 2 μsec. A minimum width of 3.7 nsec (full-width at half-height) was observed on a sampling oscilloscope and a bunching factor (peak intensity in the bunch over dc intensity) of 37 was obtained. The minimum bunch width has been related to the time spreads introduced by the energy spread of the protons from the ion source and by energy straggling in the charge-changing process.
Absolute Velocity Gauge for Nuclear Particle Beams
Authors: Seagrave J. D. , Brolley J. E. , Beery J. G.
Published: February 2005

An instrument for determining the energies of accelerator particle beams in the 0–9 MeV range has been built in the form of a coaxial cylindrical cavity. It has been used to establish data points in the vicinity of the Coulomb-nuclear interference minimum in p-p scattering at 382.43 keV, with an accuracy of better than one part in 104 in energy. This is an order-of-magnitude higher precision than has been achieved previously with this technique. The collimated particle beam passes through 0.46-mm gaps separated by the 125-cm length of a hollow inner cylinder made of Invar. The beam is intensity modulated at 72 Mc, and the cavity is tuned to the modulation frequency. As the beam energy is adjusted until the particle transit time is an odd half-multiple of the cavity period, and the shunt capacitors at opposite ends are adjusted for equal and opposite electromagnetic signals across the two gaps, a sharp null occurs in the signal picked up by an antenna in the cavity. The Q was 4000. The 19F(p,αγ)16O resonance was relocated at 340.45±0.04 keV, with an order-of-magnitude increase in precision.
Field Ion Microscopy with an External Image Intensifier
Authors: McLane S. B. , Müller E. W. , Nishikawa O.
Published: February 2005

The exposure time of field ion micrographs at normalized pressure and voltage represents a figure of merit for comparison of various intensifier systems. External image intensification with a commercial RCA tube reduces the exposure time by a factor of more than 104, allowing recording of helium ion images in 1/1000 sec and standard speed motion pictures of neon ion images. Fast field evaporating metals can now be observed dynamically, and gold and copper photographs are shown as examples. The intrinsic noise of the image intensifier is not disturbing. A flicker effect is observed in the helium ion image of a stable tungsten surface at 21 °K in the presence of a small amount of water vapor. The fluctuations depend upon the local field strength; they disappear with increasing field, increasing temperature, or with the addition of a trace of neon to the imaging gas. The flicker effect is probably due to desorption of water molecules by the impact of imaging gas atoms.
Apparatus for Measurement of Peltier Coefficients
Authors: Lancia Frederick N. , McGervey John D.
Published: February 2005

An apparatus is described to measure the Peltier coefficient (P) at 0°C of materials exhibiting rather large values. The Peltier heat is calculated from volume changes of ice-water mixtures confined at the ends of the sample under investigation. Measurements performed on Bi-Te alloys are compared with Seebeck coefficients (S) using Kelvin's second relation P = ST, where T is the absolute temperature.
Magnetic-Field Spectrum Analyzer
Authors: Greenstein L. J. , Shaifer T. R. , Epstein M.
Published: February 2005

A magnetic-field spectrum analyzer has been designed and constructed which utilizes the Hall effect in indium antimonide. The magnetic field probe consists of a Hall element mounted between two ferrite flux collectors and energized by a current of linearly varying frequency which sweeps the magnetic field spectrum through a filter of 10 cps bandwith. The instrument is characterized by high sensitivity and a large dynamic range, and is designed to measure field components from 0.5 μG to 1 G in the range of 0–1000 cps. The magnetic-field spectrum is displayed on a cathode-ray tube which, together with all the other electronics, is housed in a portable cabinet. Internal circuitry is provided for accurate amplitude and frequency calibration of the instrument.
Inexpensive Automatic Recording Mössbauer Spectrometer
Authors: Lipkin J. , Schechter B. , Shtrikman S. , Treves D.
Published: February 2005

An automatic recording constant velocity Mössbauer spectrometer for 57Fe is described. The motor and the velocity sensor are integrated in a specially designed electromechanical unit. Feedback is used to make the velocity proportional to an input voltage. Recorded linewidths only 25% larger than the natural width are obtained.
Vibrating Wire Viscometer
Authors: Tough J. T. , McCormick W. D. , Dash J. G.
Published: February 2005

The damping of transverse vibrations of a wire in a viscous fluid is the basis for a viscometer of high precision and versatility. A solution to the hydrodynamic problem is indicated, and shown to be valid for a wide range of physical parameters. The device is simple in operation and design, adaptable to various decay constant measuring techniques, and requires only a small volume of sample fluid. The viscosity of liquid helium II between 1.10°K and the lambda point has been measured with this technique, and shows a mean scatter of about 2%. This technique is particularly appropriate for fluids of low viscosity.
Machine for Producing Square Torsion Pulses of Microsecond Duration
Authors: Pope D. P. , Vreeland T. , Wood D. S.
Published: February 2005

A dynamic torsion testing machine has been built for the purpose of applying a known constant shear stress to a 12.7-mm-diam cylindrical test specimen for very short periods of time. The shear stress at the surface of the specimen rises from zero to any desired value in the range 0 to 3000 psi, within a period of 4 to 6 μsec. The time at constant stress varies linearly with axial position from the free end of the specimen ranging from 0 to about 500 μsec. The stress is removed within a period of 4 to 6 μsec and for short specimens it remains essentially zero thereafter. This machine has been developed for the measurement of dislocation velocities up to 25 m/sec in metal single crystals.
New Technique for Designing Fast Rise Transistor Pulse Amplifiers
Authors: Rush Charles J.
Published: February 2005

A unique fast amplifier configuration is presented. With this configuration a design for a given gain and risetime can be accomplished using transistor parameters normally given on the manufacturer's data sheet. A five-stage amplifier having a gain of 1580 and a risetime of 3.05 nsec was built using the technique presented here.
Fraction Collector for Distillation Columns Operating at Reduced Pressure
Authors: Van Swaay M.
Published: February 2005

A fraction collector for distillation columns operating at reduced pressure is described. With the apparatus, fractions of known volume can be automatically collected in collecting vessels closed with serum caps under controlled atmosphere or under vacuum. The collecting vessels are accessible at all times for further analysis of the distillate. The design is based on the use of a piston pump that ejects collected fractions into the collecting vessels via a pressure-relief valve and a needle and septum connection. Operating power for the pump is derived from a pneumatic ram. The entire operating cycle of the apparatus is controlled by feedback mechanisms.
Simple Aneroid Calorimeter with Replaceable Reaction Cells
Authors: Gunn Stuart R.
Published: February 2005

An isothermally jacketed copper block calorimeter with removable glass reaction cells used for measurement of heats of gaseous reactions from 25 to 150°C is described. Design considerations are discussed. Thermistor thermometry was employed at 150°; normalization of the data is treated.
Diamagnetic Gaussmeter
Authors: Mendelsohn L. I.
Published: February 2005

A gaussmeter is described that incorporates a diamagnetic rotor of pyrolytic graphite. The torque developed by this rotor in a magnetic field stems from its anisotropic susceptibility. Analysis and experiment show that the crest rotor torque varies as the square of the applied field. The gaussmeter scale, then, is expanded for the higher field values. The 35 kG full scale instrument described will allow direct measurement of high flux densities with greater precision than was heretofore possible with gaussmeters incorporating ferromagnetic rotors.
Technique for Measuring the Electrical Conductivity of Wakes of Projectiles at Hypersonic Speeds
Authors: Koritz H. E. , Keck J. C.
Published: February 2005

A technique is described for measuring the electrical conductivity of hypersonic wakes and any conducting medium by measurement of the Joule losses produced by the oscillating magnetic field of a circular coil surrounding it. The apparatus consists of a symmetrical rf bridge, two arms of which contain identical coils. A conducting medium inserted into one of the coils unbalances the bridge, changing the apparent impedance of the coil. Although the apparatus was designed specifically to investigate the conductivity of hypersonic wakes, it has also been used to measure the conductivity of electrolytic solutions, electrical discharges, flames, and plasmas produced in shock tubes. The measurements on electrolytic solutions gave results in satisfactory agreement with their known conductivities and provided a convenient check on the calibration of the apparatus. The shock tube measurements were made in air and agreed well with the results of Lamb and Lin [L. Lamb and S. C. Lin, J. Appl. Phys. 28, 754 (1957)]. Results of the measurements of the conductivity of electrolytic solutions, shock tube heated plasmas, and hypersonic wakes of 0.22-in.-diam nylon spheres in argon are presented.
Apparatus for Measuring Characteristics of Superconducting Tunnel Junctions
Authors: Rogers J. S. , Adler J. G. , Woods S. B.
Published: February 2005

Much information about the density of electron states in a superconductor may be obtained using electron tunneling techniques. It is of particular interest to measure the normalized dynamic conductance of superconducting tunnel junctions as a function of applied voltage. This quantity is the ratio of the dynamic conductance (di/dv)s when one or both metallic members of the tunnel junction are in the superconducting state, to the dynamic conductance (di/dv)n when both members are normal. A new method has been developed which enables measurements to be made of (di/dv)s/(di/dv)n to a few parts in ten thousand. With this method only a bridge circuit, a galvanometer amplifier, and an oscilloscope are used. The galvanometer amplifier has a passband from dc to a few cps and an input noise voltage of about 3×10−8 rms V. The circuits of the bridge and amplifier are presented and analyzed. The operation of the circuits for measuring the characteristics of low resistance specimens (≲500Ω) is described.
Two Versions of a Sliding Bar Vacuum Lock
Authors: Boerboom A. J. H. , De Jongh A. P. , Kistemaker J.
Published: February 2005

Two versions are described of a sliding bar vacuum lock for the introduction of solid samples into the ion source of a mass spectrometer. Sealing is obtained by three stage differential pumping without the use of gaskets. The first version, having a bar diameter of 25 mm, can be used up to 2-kV accelerating voltage. The second one, having a 50-mm diameter, is double acting and can be used up to 15 kV.
Effective Thickness of Two Birefringent Crystals for the Study of Natural Birefringence
Authors: Ziauddin M. , Narasimhamurty T. S.
Published: February 2005

A new optical technique using a birefringent compensator has been developed to study the natural birefringence of calcite and ADP. Experimental results are compared with those obtained by the usual banded spectrum technique. Application of this method for very highly birefringent substances is indicated.
Sliding Photometer Head for the Microspectrophotometer
Authors: Evans William L.
Published: February 2005

A sliding photometer head for a microspectrophotometer is described and illustrated in detail. This apparatus consists of a stationary table, a sliding photocell mount, and an adapter ring for the measuring ocular. The photocell mount is easily separated from the supporting stationary table which attaches to a photomicrographic bellows extension. Adjustable screws permit critical alignment. The relative simplicity, durability, ease of alignment, and ease of removal of the head from the microspectrophotometer constitute advantages of this apparatus.
Torsion Pendulum Photometer
Authors: Stimler M. , Slawsky Z. I. , Grantham R. E.
Published: February 2005

An instrument is described for making fundamental measurements of high energies of pulsed laser beams. The principle of operation is the transfer of beam-photon momentum to angular momentum of a double-reflecting ballistic torsional pendulum. The operating pressure is below 5×10−5 mm Hg. The sensitivity is 2.55±0.04 cm/J, and damping of initial oscillations before making a measurement is not required. In addition to providing the capability of simultaneous energy measurement and use of a laser beam, the measurements made with this instrument appear to be more accurate than with a commercial calorimeter used for comparison.
Alpha Particle Energy Resolution in a Liquid Scintillator
Authors: Horrocks Donald L.
Published: February 2005

The resolution of alpha particles of different energies with a liquid scintillator system has been studied for alpha particle energies of 4–7 MeV. In this work the best obtained value of the energy spread, the full width at half-maximum, of the pulse height distributions was 0.058 times the energy of the exciting alpha particle. The pulse height-energy relation for alpha particles between 4 and 7 MeV was shown to be essentially linear but not directly proportional. The quenching effects of ethyl alcohol and di(2-ethylhexyl) phosphoric acid were measured. The linewidth and relative pulse height response of the liquid scintillator system for alpha particle excitation were studied as a function of the height and cross sectional area of the sample.
Nonlinear Twin-T Network for Capacitive Transducers
Authors: Lion Kurt S.
Published: February 2005

A circuit is described which converts the capacitance variation of a capacitive transducer into analogous voltage and current signals. Direct current output voltages of the order of 10 V and dc currents in the milliampere range are obtained for a variation of capacitance of 10 pF. At maximum sensitivity, the output is practically independent of variations of the source frequency. Sensitivities of the order of 1000 V/in. can be obtained when used with transducers for the measurement of small displacements.
Fabry-Perot Dilatometer
Authors: Bottom Virgil E.
Published: February 2005

A dilatometer based upon the principle of the Fabry-Perot interferometer is described. The device is capable of measuring displacements as small as 10−7 cm or less. The measurements are made directly in terms of the wavelength of a spectral line such as the green line of 198Hg. No calibration of the apparatus is required, and it is not necessary to know the distance between the mirrors or the focal length of the lens which forms the fringes. Neither is it necessary to know the calibration of the micrometer eyepiece so long as it may be assumed that the screw is regular. The instrument should be useful for measuring magnetostriction, piezoelectric, electrostriction, and thermal expansion coefficients, especially when small samples must be used.
Correlation of I–V Characteristic with Noise for Ion Drifted p-i-n Junction Particle Detectors
Authors: Monteith Larry K.
Published: February 2005

This paper describes a technique for achieving minimum noise in a p-i-n particle detector. The reverse saturation current of the detector and its relative noise are correlated for different surface treatments. The data show that the reverse current at the detector operating voltage is not a sufficient measure of relative noise. The relative noise can be predicted from the reverse current at two to three times the operating voltage.
Ceramic Double Cell for Crystal Growth by Fused Salt Electrolysis
Authors: Kunnmann W. , Ferretti A.
Published: February 2005

A ceramic double cell for the electrolytic growth of single crystals is described. The cell is easily fabricated from low cost commercially available materials.
Design of 3He-Filled Fast Proportional Counters
Authors: Friedes J. L. , Chrien R. E.
Published: February 2005

Electron drift velocity measurements have been made on helium, helium-CO2, and helium-CH4 mixtures in order to determine the optimum design parameters for 3He-filled proportional counters. It is shown that small (<1-in.-diam) counters with neutron detecting efficiencies of greater than 1% at 1 keV and with jitter times of less than 1 μsec are practical. Calculated and measured jitter times for several counters are compared.
Low Frequency Superregenerative Oscillator Design for the Detection of Broad-Line Nuclear Magnetic Resonances
Authors: Narath Albert , O'Sullivan W. J. , Robinson W. A. , Simmons W. W.
Published: February 2005

Two superregenerative nuclear magnetic resonance detectors are described which have proved useful for the detection of broad resonances. These oscillators are capable of sensitive operation at radio frequencies as low as 2.5 Mc and quench frequencies ranging from about 50 kc near 3 Mc to 120 kc at 10 Mc. In the one case for which a comparison was made, the sensitivity of the superregenerative oscillator design was found to be comparable to that of a crossed-coil spectrometer operating under optimum conditions.
Making and Testing Small Surface Thermocouples for Fast Response
Authors: Kovács Ákos , Mesler Russell B.
Published: February 2005

Using a 200-J flashtube as a high intensity transient heat source, the response of a surface thermocouple as a function of the size and the type of junction was observed. Very thin surface junctions gave an abnormally high surface temperature during the initial temperature rise. Thick junctions gave a temperature response similar to that of a thermocouple embedded at some depth from the surface. The correlation of the observed surface temperatures to the measured heat flux showed good agreement between the experimental observations and the theoretical predictions.
Distance Detector Manometer for Measurement and Control of Liquid Helium Temperatures in Magnetic Fields
Authors: Hornung E. W. , Brodale G. E.
Published: February 2005

An accurate device for measuring and controlling the pressure of a liquid helium bath is described. The device makes use of distance detectors which sense the levels of mercury in a manometer and adjust heat to the helium bath to keep the pressure constant. The device, unlike those using resistors as a sensing element, gives highly accurate control in the presence of changing magnetic fields. The manometer is also useful for general pressure measurements, giving rapid, accurate, and easily read results.
Multiplate Shower Counter for High Energy Gamma Rays
Authors: Homma S. , Kikuchi R. , Kitagaki T.
Published: February 2005

A type of total absorption photon counter was constructed and calibrated. It is a multiplate shower detector composed of seventeen 10-mm-thick sheets of plastic scintillator, sandwiched by sixteen 3-mm-thick sheets of lead. The total radiation length of the counter is 9.5 radiation lengths. The scintillation light produced in the plastic sheets is detected by four phototubes. The two counters constructed were calibrated by using electrons over the energy range from 60–600 MeV, and they showed the same characteristics. The energy response of the output pulse height from either counter is nearly proportional to the energy of incident electrons over the range studied, and the energy spread of the counter, defined by the full-width of the distribution at the half-maximum, ΔE over E, is about 30% at 600 MeV and proportional to E−1/2.
Simple Electron Diffraction Camera for the Examination of Alkali Antimonide Photoelectric Films
Authors: McCarroll W. H. , Simon R. E.
Published: February 2005

A simple and inexpensive electron diffraction apparatus has been built which can be used for the preparation of photocathodes and the subsequent examination of their patterns under conditions of high vacuum necessary for the preservation of photoelectric sensitivity. The tube consists essentially of an oscilloscope-type envelope with a high voltage display kinescope electron gun assembly and a side arm in which the photoelectric film can be prepared. The sample can then be moved in front of the electron beam, and the resultant electron diffraction pattern is displayed on a phosphor screen. Up to five cathodes can be prepared and examined separately in the same tube. Several sensitive photocathodes have been prepared and their diffraction patterns examined. The technique has been particularly useful for following the formation of multialkali cathodes of the type Na2KSb from the deposition of the initial antimony layer to the final sensitive photocathode surface.
Automatic Plotting of Spin-Wave Instability Threshold Data
Authors: Purnhagen Tom G.
Published: February 2005

A method for automatically plotting spin-wave instability threshold data (butterfly curves) is described. The plotting system uses a servo loop to lock the power level of a microwave signal at the spin-wave instability threshold level while the applied magnetic field is swept. Typical data obtained using this method are presented and compared with data taken manually, and general agreement is noted.
Speer Carbon Resistors as Thermometers for Use Below 1°K
Authors: Black W. C. , Roach W. R. , Wheatley J. C.
Published: February 2005

A survey has been made of the properties of certain resistors made by the Speer Carbon Company to determine whether they might be suitable for resistance thermometry below 1°K. It is found that resistors of grade 1002 in various nominal resistance values from 100–500 Ω are the most suitable for very low temperature work. Resistors of the same nominal size matched at room temperature and at 4°K have rather similar characteristics down to 0.02–0.03°K. The resistors may also be baked at a sufficiently high temperature to allow them to be sealed into apparatus using thermocuring epoxy resins. A magnetic field perpendicular to the axis of the resistors decreases the resistance at constant temperature.
Direct Glass-Metal Seals
Authors: Gifford F. E. , Dolenga Arthur
Published: February 2005

Direct glass-metal seals have been developed for use in tubes containing hot alkali vapors. Six types of glasses (Corning code Nos. 7052, 7056, 7720, 3320, 1720, 7740) in conjunction with three types of metals (tungsten, molybdenum, and Kovar) were employed in this study. Combinations of glasses and metals previously considered incompatible by other sealing methods were successfully united by utilizing this technique. Tubes made with these seals have been thermally cycled and they remained vacuum tight.
Fast InSb PEM Detectors for Optical Maser Studies to 7 μ
Authors: Zitter R. N.
Published: February 2005

An indium antimonide photoelectromagnetic (PEM) detector, operating at room temperature, has shown capabilities as a fast demodulator for optical maser studies at wavelengths up to 7 μ, well beyond the spectral range of phototubes and Ge or Si photodiodes. The detector responds to modulation frequencies of at least 150 Mc, and the use of more highly doped material could result in speeds up to 1 kMc. Construction is simple, no bias current is required, and detector response should be linear even for large incident intensities; the main disadvantage is the relatively small amount of output power and the consequent necessity of low noise amplifiers. An important application is the study of the high gain transitions in xenon and neon lasers.
New Shear Apparatus for Temperatures of 1000°C and Pressures of 50 Kilobars
Authors: Riecker R. E.
Published: February 2005

A new shear press capable of simultaneous pressures and temperatures of 50 kbar and 1000°C incorporates a 5-kW high frequency induction heater, 300-ton hydraulic jack, ½-hp motor, and 3-pinion gear train for strain rates of 0.01–10 rph, and tungsten carbide ball-type anvils faced to diameters of ¼-1 in. The press, designed to simulate earth depths of 30–200 km, determines shear strength, viscosity, and internal friction data for rock and mineral samples of lower crust and upper mantle composition under geophysically realistic conditions of high temperature and pressure.
Achromatic Translation System for Charged Particle Beams
Authors: Swenson D. A.
Published: February 2005

An assembly of bending magnets and magnetic quadrupole lenses was found which causes the axis of a beam of charged particles of momenta p±Δp to be shifted from its original axis to a parallel line displaced from its original axis by a distance d. A study of this transport system demonstrates that it is possible to choose the parameters of the system in such a way that the entire system has an acceptable effect on the transverse motion of the beam, and so that the system is achromatic to first order in Δp/p. A typical transport system is given, and results are presented in graphical form for a range of parameters encompassing the typical values.
Damping of a Resistive Wall Beam Instability in the Cosmotron
Authors: Barton M. Q. , Cottingham J. G. , Tranis A.
Published: February 2005

In several particle accelerators the growth of coherent axial betatron oscillations has been observed. In the Cosmotron these oscillations have been damped by an electronic system which detects the axial beam position and applies a signal of proper strength and phase to a set of deflection electrodes.
Performance Studies of a Quadrupole Mass Filter
Authors: Brubaker Wilson M. , Tuul Johannes
Published: February 2005

The transmission efficiency and the resolving power of a quadrupole mass filter have been investigated as functions of entrance aperture size and frequency of excitation. The aperture size was varied from 10 to 40% of the rod diameter, and the frequency of excitation from 0.87 to 1.7 Mc. Larger transmitted ion currents at lower transmission efficiencies are observed with the larger aperture sizes. Higher resolution is obtained more readily with smaller apertures and higher frequencies.
Supersonic Annular Nozzle as a Differential Barrier
Authors: Stallings Charles H. , Martin David H.
Published: February 2005

Supersonic annular nozzles were used as a means of maintaining vacuum pressure differentials between two points, without the use of solid barriers or small constrictions as a mechanism for injection of ion beams into gases. Ambient atmospheric air was expanded into a small stilling chamber; this air was then expanded so as to form an annular supersonic stream in a chamber which was pumped by a six-stage steam jet ejector. With a center opening of 1.25 in. diameter and the air stream expanding into 15 mTorr, an optimized nozzle will produce, under small loads, a pressure of 3 mTorr upstream of the opening. With a nozzle of center opening 0.5 in. in diameter expanded into 15 mTorr, an upstream pressure of 0.9 mTorr can be maintained.
Ultraviolet Lamp for the Generation of Intense, Constant-Shape Pulses in the Subnanosecond Region
Authors: D'Alessio Juan T. , Ludwig Peter K. , Burton Milton
Published: February 2005

A commonly available mercury contact relay is modified to make a uv lamp which yields a spark with approximately 100 times the intensity of the original relay and with constant characteristic risetime of 0.4 nsec, decay time of 0.55 nsec, and half-width of 0.5 nsec. The lamp can be used not only for fluorescence decay-time studies, but also for electrical applications in the subnanosecond region. It has been operated in the range 3 to 50 000 pulses per second.
Acoustical Liquid Drop Holder
Authors: Hanson A. R. , Domich E. G. , Adams H. S.
Published: February 2005

An acoustical liquid drop holder is described in which radiation pressure is used to support, at rest, drops in the diameter range of 100–3000 μ. The theory of King is applied to give a qualitative explanation of its performance. Design features of a piezoelectric ultrasonic vibrator are discussed. The support of liquid drops in a shock tube is given as an application of the drop holder.
Spark Chamber and Magnet System for Photographing Cosmic-Ray Tracks at Balloon Altitudes
Authors: DeShong James A. , Daniels Robert E. , Hildebrand Roger H. , Meyer Peter
Published: February 2005

A spark chamber system, consisting of five spark chambers and a deflection magnet, is used to photograph tracks of cosmic-ray electrons at 130 000 feet. Four trajectory spark chambers display the deflected particle track from which particle energy and sign may be determined for magnetic rigidities up to about 2 BV. A tantalum plate spark chamber at the exit detects electrons by production of cascade showers.
Vapor Pressure Measurements at High Temperatures Using a Recording Microbalance
Authors: Zavitsanos P. D.
Published: February 2005

A fast technique for measuring vapor pressures at high temperatures has been developed. It consists of measuring the rate of effusion from a Knudsen cell by continuously monitoring the weight of a collector with a recording microbalance. Electron bombardment heating was employed and accurate temperature control was achieved by automatically adjusting the filament current so that the emission current remained constant. Its utility was demonstrated by measuring the vapor pressure of silver. It is shown that the measured vapor pressure and heat of sublimation are in excellent agreement with the best literature values.
X-Ray Diffraction Camera Using Polaroid Film
Authors: Schmidt P. H. , Spencer E. G.
Published: February 2005

A description is given of a camera, holder, and technique which were developed for high speed back-reflection Laue photography using Polaroid film. The exposure-development sequence is 1 to 2 min, a time which is negligible compared to the time required for standard wet-processed x-ray films. Several cameras have been constructed and now are being used extensively on a routine basis. Typical results are described and possible further improvements are discussed.
Sensitive Method for the Measurement of Nonlinearity of Electrical Conduction
Authors: Skov Charles E. , Pearlstein Edgar
Published: February 2005

If an ac potential V=V0 (cosωt+cos2ωt) is applied to an element whose current-voltage relationship can be expressed as I=aV+bV2+cV3+…, there will be a dc component of the current proportional to the coefficient c. Equations are developed and apparatus is described for using this fact to measure deviations from Ohm's law. Experimental results are presented which show that the method and apparatus are capable of measuring these deviations at least down to one part in 108.
Twenty-One Centimeter Traveling-Wave Maser for the Harvard Radio Telescope
Authors: Hensel M. L. , Treacy E. B.
Published: February 2005

A traveling-wave maser tunable over the frequency range of 1340 to 1430 Mc has been developed and constructed for use in radio astronomical research. It uses ruby as the maser material and a comb as the slow-wave structure. The net gain exceeds 30 dB over most of its tuning range, while the average instantaneous bandwidth is about 11 Mc. It has been designed for operation at 4.2°K.
Technique for Measuring Self-Absorption of Spectral Lines in Plasmas
Authors: Dickerman P. J. , Deuel R. W.
Published: February 2005

The instrumentation requirements for determining the self-absorption of spectral lines in a radiating gaseous system have been studied using a two-path method with an argon arc plasma. By observing lines with known transition probabilities, it is possible to check the system using a direct comparison of theoretical and experimental absorption coefficients. Results for 13 argon lines in the near-infrared suggest an experimental procedure that can be used, in general, provided the source possesses cylindrical symmetry.
Coplanar Aperture Lens
Authors: Heil Hans , Wagner William G.
Published: February 2005

The focal length, the position of the principal plane and of the virtual image, as well as the spherical aberration constant for the coplanar aperture lens (which consists of a cathode in the form of a disk and an anode occupying the rest of the plane of the cathode) have been measured in the electrolytic tank trajectory tracer and calculated analytically. Such a lens is an essential element of electron energy spectrometers of the retarding potential type. The knowledge of the spherical aberration constant permits the design of a two-lens system for an analyzer, in which the aberrations of the two lenses cancel partially. The effects of lens aberrations on the energy resolution of the instrument are calculable with the aid of the optical constants and, accordingly, the design may be optimized.
High Voltage Flash Photolysis Lamp
Authors: Lindqvist Lars
Published: February 2005

A condensed discharge flash photolysis light source is described. A short flash duration time (``1/e-time'' 3 μsec at 1450 J, 10 μsec at 7200 J) was obtained by the use of high voltage capacitors (40 kV), and by dissipating the capacitor energy in four flash tubes (length, 20 cm each) connected in series for easy triggering. The characteristics of flash tubes at high discharge voltages are studied, in particular with respect to the ``afterglow'' effect.
Lifetime of Helium-Neon Lasers
Authors: Turner R. , Baird K. M. , Taylor M. J. , Van Der Hoeven C. J.
Published: February 2005

Experiments have been performed in order to ascertain the factors affecting the lifetime of an rf excited, internal reflector, helium-neon laser oscillating at λ6328 Å. Using the results of the experiment it has been found possible to make practical lasers of simple design having lifetimes of over 1000 h operation. This performance has been achieved by improving the reflectors and by adjusting discharge conditions and gas filling to optimum.
Method of Continuous Shock Front Position Measurement
Authors: Heusinkveld M. , Holzer F.
Published: February 2005

A method (called ``slifer'') for continuously measuring the position of a shock front in a solid, opaque medium has been developed. The sensing element is a shorted transmission line which forms part of the inductance of an oscillator. As the stress wave moves along the line, it crushes the cable progressively, thus changing the cable inductance and the oscillator frequency. The oscillator output is recorded as a function of time. This frequency record is converted to uncrushed cable length, and finally to a position versus time relation.
Novel Method of Measuring Elastic and Anelastic Properties of Solids
Authors: Fraser D. B. , LeCraw R. C.
Published: February 2005

A technique has been devised whereby the elastic and anelastic properties of solids can be measured both as a function of frequency and temperature. A small sphere, of the order of a few millimeters in diameter, is placed without bonding on a shear mode transducer. The transducer is driven with a pulse at one of the sphere's resonant frequencies and the free decay of the sphere's vibrations is observed by switching the transducer to a receiver. From the decay of the vibrations, the internal friction Q−1 may be calculated. Various modes may be excited and from comparison with the computed mode spectra of an isotropic solid, the Lamé constants, λ and μ, and Poisson's ratio may be calculated directly. Measurements have been made over a range of temperatures from 1.4 to near 400°K, the present upper limit being set by the solder connections to the transducer. Several materials have been tested and the results for two single-crystal nonmagnetic garnet spheres are given as representative of the capabilities of the technique for reasonably isotropic substances. The values of Q−1 for these garnets lie between 3×10−7 and 2×10−5 at a frequency of approximately 2 Mc.
Simple Determination of the Angular Deviation Between a Prepared Crystal Surface and the Crystal Plane
Authors: Lange F. F.
Published: February 2005

A method is described to measure the angular deviation between a prepared crystal surface and the crystallographic plane in question. The method employs a simple device used in conjunction with a Laue camera, thus eliminating cumbersome optical techniques prevalent in other methods. The deviation angle can be determined directly from the Laue photograph by a simple calculation.
Time-Shared Time-of-Flight Analysis by Computer
Authors: Chrien R. E. , Rankowitz S. , Spinrad R. J.
Published: February 2005

A time-shared computer-centered data collection system has been placed into operation at the Brookhaven Graphite Research Reactor. The system provides simultaneous data collection and sorting for two physically unrelated neutron time-of-flight experiments in time-share with a general computation facility. A general purpose stored-program digital computer with a 4096 word, 24-bit memory is the heart of the system. The computer system provides, for the ``fast neutron chopper'' experiment, a 1024-channel time analyzer for total or partial neutron cross section experiments, three elapsed-time clocks, three total events scalers, two monitor scalers, and a chopper tachometer. At the same time, for the ``slow neutron chopper'' experiment, the system provides a 256-channel time analyzer, a clock, a total events scaler, a monitor scaler, and a chopper tachometer. The two experiments are independent of one another and are controlled by the typing of four-letter mnemonic codes on the system typewriter. A live cathode-ray tube display of either experiment is present at all times except when the time-shared computational facility is being used. Connections between the computer and the external analog-to-digital converters are made on a patchboard, allowing convenient control of data format. The system has been designed to facilitate expansion to multiparameter data handling.
Cube-Root Coordinate Color-Difference Computer
Authors: Faulhaber M. E. , Schnelle P. D.
Published: February 2005

An electromechanical analog computer is described which automatically converts tristimulus values directly to visually compatible color differences, ΔL, Δa, Δb, and ΔE, in the cube-root coordinate system. The range of this computer is suitable for color arrangement and formulation purposes, and its accuracy and reproducibility meet the requirements for critical industrial color control applications. The equations solved by the computer are derived from the cube-root coordinate system; analog methods for generating these equations are outlined; typical operating procedures are illustrated; and technical specifications are detailed.
New Type of Flux Meter for the Measurement of High Magnetic Fields at Low Temperatures
Authors: Houck J. R. , Bowers R.
Published: February 2005

A flux meter is described which is convenient for high field measurements at low temperatures. The device is based on a magnetoplasma resonance and produces an audio-frequency signal whose frequency is proportional to the magnetic field. The device has a linearity of better than 1% between 10 and 80 kG.
Electrostatic Torsion Balance for Magnetic Film Measurements
Authors: Siegle W. T. , Beam W. R.
Published: February 2005

An automatic torsion balance has been built for measurement of magnetic film properties. The use of electrostatically generated restoring torques results in a substantial simplification of the suspension system over previous arrangements. Furthermore, the reduced sensitivity of this system to background vibrations has made the attainment of 3×10−4 dyn-cm sensitivity fairly simple.
Reference Tables for Platinum 20% Rhodium/Platinum 5% Rhodium Thermocouples
Authors: Bedford R. E.
Published: February 2005

Reference tables have been set up for platinum 20% rhodium/platinum 5% rhodium thermocouples over the temperature range 0–1800°C based on measurements made in air with thirteen thermocouples from four wire lots. The thermocouples were calibrated by comparison with standard platinum 10% rhodium/platinum thermocouples from 0 to 1500°C; by freezing point determinations of zinc, antimony, silver, and gold; by melting point determinations of palladium and platinum by the wire method; by comparison with an optical pyrometer from 1200 to 1800°C; and by intercomparisons (with each other) from 0 to 1750°C. The accuracy obtained in the use of the tables is discussed, and data relating to the stability and reproducibility of these thermocouples is presented. Expanded versions of the tables are available as NRC Report No. 7930. A description of a high temperature vacuum furnace is given in the Appendix.
Electrical Conductivity Cell for Organic Semiconductors
Authors: LaFlamme Paul M.
Published: February 2005

This report describes the construction, calibration, and performance of a simple electrical conductivity cell for use in measuring the electrical conductivity: temperature relationship of organic semiconductors and related materials. The cell allows operation in a vacuum or inert gas atmosphere over a temperature range adequate to make rapid and reliable measurements of ρ, ρ0, and Δ EG for powdered organic semiconductor samples. Resistivities in the range of 1<ρ<108 Ω-cm may be measured with an estimated error of ±1.2%.
Relativistic Equations and Tables for Ion Energy Determination by the Crossover Technique
Authors: Smythe Rodman
Published: February 2005

A relativistically exact equation is derived for the scattering angle at which ions elastically scattered from one kind of nuclei have the same energy as they do when inelastically scattered from heavier nuclei. Tables are presented for protons, deuterons, and alpha particles using the 4.433- and 9.629-MeV levels of 12C. The tables include incident energies from approximately 5 to 60 MeV.
Double-Probe Method for Unstable Plasmas
Authors: Chen Francis F.
Published: February 2005

In order to check the accuracy of electron temperature measurements by the Langmuir probe method in a plasma with large fluctuations in space potential, a method has been used which employs a floating probe in addition to the usual biased probe. The results show that the oscillations do not noticeably affect temperatures found by the standard method, so that it is not usually necessary to use this two-probe time-resolved method even in the presence of fairly large oscillations. Furthermore, the usefulness of this method in the case of an inhomogeneous plasma is illustrated.
Angle Measuring Interferometer
Authors: Marzolf John G. , J. S.
Published: February 2005

A cube-corner angle-measuring interferometer has been developed which reproduces angles up to 30° with a precision of 0.01″. The angular dependence of the interference order rigorously follows a sine law and any angle in the range of the interferometer may be measured with an accuracy which is limited only by the error in the full scale calibration angle. Theory, construction details, and alignment and calibration procedures are given. The instrument is insensitive to both translation and tilting of the axis of rotation. As constructed the instrument had a range of ±15°, and suggested improvements should increase this to ±20° or more. The 0.01″ precision is not a limitation inherent in design, but was due both to imperfections in available optical parts and to building vibration.
Apparatus for X-Ray Diffraction Studies of Confined Fluids
Authors: Honeywell W. I. , Knobler C. M. , Smith B. L. , Pings C. J.
Published: February 2005

An apparatus is described for studies of the x-ray diffraction of liquids in the temperature range 80–300°K and at pressures up to 100 atm. The device is compatible with a commercial goniometer and is usable in both Debye-Scherrer and parafocusing geometries.
Internal Pulse Amplification in Silicon p-n Junction Radiation Detection Junctions
Authors: Huth Gerald C. , Trice James B. , McKinney Russell A.
Published: February 2005

Internal pulse amplification in silicon p-n junction radiation detectors has been observed in the energy range from 0.05 to 1.0 MeV incident. The detectors are operated in the preavalanche region with significant multiplication occurring at internal electric field values of greater than 150 kV/cm. Pulse resetimes as fast as 4 nsec have been measured for internally amplified pulses.