bluuebunny/crossref_metadata_2025 huggingface dataset:
Eddy-Current Phenomena in the Cosmotron
Authors: Blewett M. Hildred
Published: February 2005

In the Cosmotron magnet, eddy currents in the half-inch laminations cause no serious effects except for a small increase in n value at injection time. This increase needs no correction since it is compensated by the reversed slope of the remanent field. Analyses of eddy-current effects in other metallic components of the Cosmotron are included, for example, in the pole-face windings and in the stainless steel vacuum chamber. Serious shifts in the magnetic median surface result from eddy currents that arise when either inner or outer vertical wall of the vacuum chamber is misaligned.
Calculation of the Protons' Radial Oscillations at Injection
Authors: Courant E. D. , Sternheimer R. M.
Published: February 2005

The radial paths of the first two revolutions after injection have been calculated for variations in injection timing, injection position, and initial angular direction. Graphs of some typical cases are included.
Photocathode Uniformity and Resolution of Scintillation Spectrometers
Authors: Godlove T. F. , Wadey W. G.
Published: February 2005

Sixteen photomultiplier tubes have been studied to determine the relation between the uniformity of their photocathodes and the resolution obtained from a γ-ray scintillation spectrometer using each of them. The sensitivity contours of the tubes have been plotted. The resolution was found to be related to the average sensitivity but could be improved by concentrating the light on the most sensitive part of the photocathode. Techniques for studying sensitivity with an artificial light flasher are described.
The Calibration of the Slotted Section for Precision Microwave Measurements
Authors: Oliner Arthur A.
Published: February 2005

The basic slotted section measurements of VSWR and the location of the voltage minimum are affected by the variety of errors inherent in the slotted section. Considered here are those effects, important for precision measurements, introduced by discontinuities due to the end of the slot, and due to possible adaptors, coupling elements, bead supports, etc., and by the presence of the slot in creating a guide wavelength and characteristic impedance slightly different from that of a guide without a slot. A calibration procedure is presented which compensates rigorously for these effects in a simple fashion.
Precision Measurement of Uniformity of Materials by Gamma-Ray Transmission
Authors: Berman Arthur I. , Harris John N.
Published: February 2005

The uniformity of the product of thickness and density (i.e., mass per unit area) of materials of constant mass absorption coefficient is determined by measurements of the variation in gamma-ray transmission. The radiation is detected with a scintillation detector and vibrating-reed electrometer. For a given incident intensity, maximum sensitivity is attained when a source is chosen which emits gamma rays whose mean free path in the material under investigation equals the thickness, assuming the detector response is a slowly varying function of quantum energy. This optimum condition for cobalt-60 radiation obtains for thicknesses of 3, 1, and ½ in. of Al, Fe, and U, respectively; using a one-curie source, variations of 0.01 percent in the uniformity of plates of these thicknesses have been measured. The method may be applied also to the scanning of curved surfaces and extended materials where the source and detector cannot permanently be fixed with respect to each other. For this latter case, the problem of compensating for the effect of misalignment of source and detector is considered.
Measurement of Pressure Transients
Authors: Eckenrode Robert T. , Kirshner Howard A.
Published: February 2005

A general review of fluid pressure transient measurement and instrumentation is presented. The review is designed to acquaint the reader with the basic problems encountered in transient measurement and to discuss the various types of pressure gauges available. The measurement problems include such topics as frequency response, thermal and electrical stability, calibration techniques, and interpretability of results. Some of the more important gauge types covered are mechanical, piezoelectric, condenser, strain, inductance, and optical. The discussion of these gauges includes a critical evaluation of the important characteristics of each, followed by a table comparing them with each other on the basis of these characteristics. With this background, the choice of a gauge best suited for a particular transient measurement problem should be facilitated.
A Logarithmic Barometer
Authors: Yngve Victor H.
Published: February 2005

The design of a barometer is described which achieves a logarithmic response over a wide range of pressures by the use of two fluids and a tube of varying cross section. Application of the principle to barometers with other useful nonlinear scales is discussed.
A Precision Multiple-Mercury-Column Manometer
Authors: Roebuck J. R. , Ibser H. W.
Published: February 2005

The 200-atmos mercury manometer described in previous papers is studied experimentally and revised, especially by removing the mercury reservoirs from the measuring system. A rotating loaded piston is used to provide a constant test pressure, and details as to its construction and use are given, as also for the toluene pump, valves, unions, Invar tape, and cathetometers. The temperature control of the manometer and the management of its fluids are described. The barostat piston was known to vary 2 to 3 parts per 104 in. cross section. By means of a screw-driven plunger the barostat was held manually at the same vertical position during each of a series of 8 readings of the barostat pressure. The maximum divergence from the mean of the series is 0.83 part per 104, and the average of the absolute values of the divergences from the mean is 0.30 part per 10. It is concluded that the manometer can be relied on to measure a pressure of about 200 atmos to within 1 part in 104.
Noise Discriminator for Periodic Signals
Authors: Conger Robert L. , Schilberg Lloyd E.
Published: February 2005

An electronic apparatus has been designed which can separate random noise, 60 cps pickup, and other disturbances from a periodic signal of any wave form, including a square-wave form, with little distortion of the shape of the periodic signal, provided the frequency of the disturbance is not a multiple of the signal frequency. This noise discriminator is not a filter in the morphological sense, but an instrument which synthesizes a new signal built up of the fundamental and higher harmonics of the input signal. The output has the same shape as the noise-free portion of the input but is at a much lower frequency.
Adsorption Studies on Clay Minerals. III. A Torsion Pendulum Adsorption Balance
Authors: Gelewitz Edmund W. , Thomas Henry C.
Published: February 2005

The construction, operation, and inherent errors of a quartz fiber torsion pendulum balance are described. Determinations of the period of the pendulum with an accuracy of 50 μsec are easily possible. These determinations make possible the indirect weighing of a two-gram sample to 0.1 mg.
An Apparatus for the Measurement of Systolic and Diastolic Pressures
Authors: Landsman Robert M.
Published: February 2005

Two electronic voltmeters are used to present the systolic and diastolic blood pressure. One of these voltmeters is the peak reading type to show the systolic pressure, the other is a modified peak reading voltmeter which presents the diastolic pressure. This unit is applicable to any system which converts pressure to a varying dc voltage.
Subharmonic Crystal Oscillators
Authors: Thompson Moody O. , Tschiegg Carroll E. , Greenspan Martin
Published: February 2005

Relaxation oscillators are described of which the fundamental frequency is a high-order (up to 10 000) subharmonic of the frequency of a quartz crystal which serves as the controlling element. Except for the addition of the crystal, the circuits are no more complicated than conventional ones.
A Forward Angle Light Scattering Camera for Determining Size Distribution in Aerosols
Authors: Lee Pui-Kum , La Mer Victor K.
Published: February 2005

The light scattered in the near forward direction from individual dioctyl phthalate (DOP) droplets flowing in a thin stream of known thickness and illuminated by a high intensity electronic flash tube is recorded photographically for the determination of number concentration and size-frequency distribution. The photos are taken slightly off-focus so that the pin-point images at focus are expanded into diffraction patterns. The optical density of each pattern is used as a measure of its droplet size.

The correlation between optical density and droplet size was determined with a series of aerosol preparations of known size and of size distribution characterized by a standard deviation which is about 10 percent of the mean. This correlation permits the translation of the measured frequency curve for optical density into a size-frequency distribution. The method has been checked by determining the size-frequency distribution of synthetic mixtures of known size. The reliable range of measurement extends from 0.12 to 0.50 μ radius.
New Method of Determining Ultrasonic Wavelength in Liquid
Authors: Yamamoto Nobuyoshi
Published: February 2005

A method for the rapid measurement of the velocity of sound in liquids is described. An ultrasonic grating is established in the liquid under investigation. Light from a narrow slit is diffracted in passing through the liquid. It is shown that the wavelength of the sound can be measured by widening the slit until one order of the diffraction spectrum connects with the next. Results of measurements on several liquids are compared with those of other investigators.
A Mass Indicator Using a Vibrating Coil Magnetometer
Authors: Caldecourt V. J. , Adler S. E.
Published: February 2005

A vibrating coil magnetometer has been developed which provides precise and continuous indication of the strength of a magnetic field. The device is used on a sector mass spectrometer to obtain both visual mass indication and spectra calibration in the mass range of 2–400.
A Simple High-Temperature Microwave Spectrograph
Authors: Tate P. A. , Strandberg M. W. P.
Published: February 2005

A microwave absorption cell of simple construction has been designed to work in the temperature range of 600°C to 1000°C. The cell consists of a piece of stainless steel wave guide equipped with a Stark septum and enclosed in a Vycor envelope. The furnace and temperature control equipment used with the cell are described. Electronic detection equipment is similar to that used with other Stark-modulation microwave spectrographs.
Thin-Wire Thermometer for Radiosondes
Authors: Piccard Jean , Larsen Harold , Blomstrand John
Published: February 2005

It is shown that the thinner the thermometer element of a sounding balloon, the smaller the errors due to radiations from the sun and the earth. Such a thin wire thermometer made from white gold wire as described herein, was delivered March 20, 1941, to the U. S. Weather Bureau. The instrument sends off its findings by radio signals in Morse code. A very efficient vibration absorber for the instrument is described.
Apparatus for X-Ray Diffraction Studies of Metals under Controlled Stress at Elevated Temperature
Authors: Birks L. S.
Published: February 2005

A Geiger-counter x-ray spectrometer was constructed for the dynamic study of phase changes and other phenomena in metals under controlled stress conditions at elevated temperatures. Temperature could be controlled from room temperature to the melting point of steel, and stress was independently varied from zero stress to the breaking stress of stainless steel. Applications included isothermal and athermal transformation studies under tensile stress in pearlite, bainite, and martensite.
Relay Time-Division Multiplier
Authors: Korn Granino A. , Korn Theresa M.
Published: February 2005

This paper describes the theory and design of a new low-cost analog multiplier suitable for use with the dc analog computers now widely applied as differential analyzers and equation solvers. The new multiplier comprises a simple relay circuit utilizing the time-division principle. The multiplier accepts input voltages of both signs and is capable of multiplication to within an accuracy of 3.5 percent of full scale at zero frequency and 7 percent of full scale through the frequency range between 0 and 10 cycles per second. Greater accuracy is possible through sacrifices in the useful frequency range. The dynamic range of input and output voltages is −80 volt to +80 volts. The multiplier circuit proper contains no vacuum tubes, servomechanisms, or power supplies but utilizes one of the operational amplifiers of the dc analog computer with which it is used.
An Integrating and Differentiating Bar-Magnet Velocity Meter for Use in Ballistocardiography
Authors: Perls Thomas A. , Kissinger Charles W.
Published: February 2005

An integrating and differentiating bar-magnet velocity meter is described. Design criteria are presented for integrators and differentiators to meet given specifications of frequency response. In the design of the differentiator, use is made of a small amount of resonance magnification in a suitably damped series-resonant circuit. Test procedures are described for determinations of frequency response, sensitivity, and linear range of the instrument. Examples are given of sensitivity adjustment and installation procedures for use of this instrument in ballistocardiography. A ``60 cps hum compensator'' is used to cancel out any objectionable 60-cycle pickup from the power line.
Diffusion Cloud Chambers for Cosmotron Experiments
Authors: Fowler W. B. , Shutt R. P. , Thorndike A. M. , Whittemore W. L.
Published: February 2005

Two diffusion cloud chambers operating with H2 or He at pressures up to 300 lb/in.2 have been built primarily for use at the cosmotron. One is a 16-in. diameter chamber operated in a 10 500 gauss field. The other chamber has an effective length of 6 ft, width of 11 in., and no magnetic field. Photographs obtained with the long chamber are scanned in a special projector, which foreshortens beam tracks so that up to 75 percent of scanning time per event is saved. Beams of protons, neutrons, and mesons suitable for experiments with these chambers have been obtained. A considerable number of nuclear interactions of beam particles in the cloud chamber gas have been observed. Angles, densities, and momenta of secondary particles have been measured with acceptable accuracy. Consequently these cloud chambers provide a useful tool for the study of high-energy nuclear interactions.
New Sensitive Piezoelectric Detector
Authors: Pepinsky R. , Baecklund J. , Diamant H. , Perdok W. G.
Published: February 2005

A highly sensitive Giebe-Scheibe apparatus for piezoelectric detection is described, incorporating the frequency sweeping technique of Perdok and van Suchtelen. Provision is made for observations over wide temperature ranges.
An Electron Interferometer
Authors: Marton L. , Simpson J. Arol , Suddeth J. A.
Published: February 2005

An interferometer of the amplitude-splitting type has been constructed which operates with electron beams and produces a system of fringes in the viewing instrument. The appearance of the fringes may be varied at will by introducing changes in one of the (electron) optical paths. The instrument utilizes crystalline diffraction for beam splitting and recombining.
An Improved Halide Ion-Sensitive Sampling Surface for Water Aerosols
Authors: Farlow Neil H.
Published: February 2005

An improved type of transparent film sampling surface is presented for 25μ to 400μ diameter water droplets which contain halide ion concentrations greater than 0.5 percent by weight. A preliminary calibration of droplet size vs film spot size has been constructed. From the calibration data an experimental estimate is made of the chloride ion sensitivity per drop size on the film.
Electron-Bombardment Ion Source for Mass Spectrometry of Solids
Authors: Cameron A. E.
Published: February 2005

An ion source structure is described which is specifically designed for slow electron ionization of vapors of salts. This may be used up to 550°C. The ion chambers are rapidly interchangeable and memory effects between samples are undetectable over moderate changes in concentration. Some of the characteristics of this source are discussed and its advantages indicated.
Moving-Strip Fourier Analyzer
Authors: Grenville-Wells H. J.
Published: February 2005

A device embodying Robertson's principle of movable strips is described for performing two-dimensional Fourier summations of the type ΣHΣKF(hk)[cos2π(hX+kY)] without first rearranging them in the form ΣHΣKF(hk)[cos2πhX·cos2πkY−sin2πhX·sin2πkY]. The same strips can be used to evaluate sine summations and some three-dimensional summations directly. The electron density can be readily calculated at selected individual points in the projection. Summations can also be completed by means of masks. The operation of the device, which can accomodate values of F(hk) = ± (1 to 99), h= −15 to +15, k=0 to 15 for X, Y = 1/36 of the repeat distance, is described, and illustrated by an example.
Airborne Infrared Spectrograph
Authors: Hargens C. W.
Published: February 2005

An airborne infrared spectrograph has recently been completed in which electronic techniques are used in novel ways to record 10 spectral samples and the total radiation signal for the wavelengths between 1 and 25 microns. The rapid operation of the sensing and recording systems makes it possible to obtain the complete analysis each 0.08 second together with other pertinent data.
Isothermal Jacket Microcalorimeter for Heat Effects of Long Duration
Authors: Gordon Paul
Published: February 2005

A Borelius type isothermal jacket microcalorimeter has been designed and constructed. It consists essentially of a vapor thermostat providing a constant temperature environment about a chamber containing the specimen and measuring device, the latter being a high-sensitivity differential thermopile. With one set of thermopile junctions kept at constant temperature by contact with the environment, and the other set arranged to vary in temperature with the specimen, a heat effect in the specimen is measured by following the difference in temperature across the thermopile as a function of time. Calibration of the apparatus is carried out by using the Peltier heat developed at the junction of a thermocouple located in an axial hole in the specimen. With an argon atmosphere in the specimen chamber, the limit of detection is a heat flow of 0.003 gram-calories per hour. The absolute accuracy of the determinations depends upon the particular conditions of a given run, but is usually in the vicinity of 2 to 5 percent.
Apparatus for Measuring the Elastic Moduli and Internal Friction of Solids from 1.7 to above 77°K and Some Values for α-Quartz
Authors: Fine M. E.
Published: February 2005

Apparatus for measuring the moduli and internal friction of solids at temperatures from 1.7 to above 77°K is described. The resonant piezoelectric method with quartz transducers is used. The frequency range is 30 to 450 kc/sec. For calibration variously oriented quartz crystals were measured over this temperature range and the values are given.
Design and Operation of Evapor-ion Pumps
Authors: Davis Robert H. , Divatia Ajay S.
Published: February 2005

A new type of high vacuum pump has been developed which makes possible the elimination of organic vapors and high vapor pressure materials from vacuum systems, without using coolant traps or baffles. This pump utilizes the gettering action of continuously evaporated titanium in conjunction with ion pumping. Some pumping speeds achieved are: 7000–8000 liters/sec at 3×10−6 mm of Hg for hydrogen, 6500–7500 liters/sec at 1.5×10−6 mm for nitrogen and oxygen, approximately 9 liters/sec at 4×10−6 mm for argon, and approximately 4 liters/sec at 3×10−5 mm for helium. The lowest pressure obtainable is about 2×10−7 mm of Hg. Dependence of pumping speeds on the temperature of the gettering surface, the pressure and the rate of evaporation of titanium is given.
High-Intensity Ion Source
Authors: Mills C. B. , Barnett C. F.
Published: February 2005

An ion source that does not require a filament has been developed for use in the cyclotron. Positive ions, from an oscillatory region within a hollow anode, bombard the cathodes at the ends and maintain them at emission temperatures. The source aperture is a lateral slit, 332×214in., in the wall of the anode. With a 10 kv (dc) accelerating potential, stable hydrogen ion beams of 330 ma (82 percent protons) have been obtained. Ion output increases as hydrogen gas feed is increased from 1 to 12 cc/min (N.T.P.). The average proton production efficiency has been 20 percent.
Variable-Frequency Microwave Cavity Spectrometer
Authors: Collier Robert J.
Published: February 2005

A variable-frequency, resonant cavity spectrometer was developed for the investigation of molecular gases in the 10-cm spectral region. Either Stark or Zeeman modulation could be applied. A single coaxial cavity, operated in the TEM mode, served as the Stark or Zeeman modulation cell and as the frequency tuning and stabilizing mechanism. The rf power transmitted through the cavity was detected by a bolometer and the signal component at the fundamental modulation frequency amplified and passed to a phase sensitive detector. The minimum detectable absorption coefficient for the spectrometer was determined to be αmin = 1×10−10 cm−1.
Solid Angle Subtended by a Circular Aperture
Authors: Garrett Milan Wayne
Published: February 2005

Methods for calculating the solid angle subtended by a circle at an off-axis point are correlated and the rates of convergence of available series are compared. Averages over a plane surface or a cylindrical volume are derived from an analogy that permits the use of existing tables of mutual inductances. Rates of variation, for displacement or rotation of the source, and the technique of computing from the zonal harmonic series are briefly discussed.
Liquid Level Indicator for Condensed Gases at Low Temperatures
Authors: Williams W. E. , Maxwell E.
Published: February 2005

The instrument described here is designed to measure, indicate, record, and control the level of liquefied gases inside a closed vessel. It is especially designed for use at low temperatures with liquefied gases such as nitrogen, oxygen, hydrogen, and helium. It operates on a capacitance principle, and makes use of the difference in dielectric constants of the liquid and vapor. The sensing element is a cylindrical capacitor whose capacitance is a function of the height of the liquid column. The sensing capacitor is one element of an automatically balanced bridge which both indicates and records the liquid level. An over-all accuracy of ±1.0 percent has been obtained. The sensitivity is adequate for use where the difference in dielectric constants of the liquid and vapor is 0.05 or greater. The instrument also incorporates a control function and supplies a controlled air pressure to a pneumatically operated valve for maintaining the level at a predetermined point.
A DC Comparison Radiometer
Authors: Selove W.
Published: February 2005

A radiometer is described which like the switching type cancels gain fluctuation effects by a comparison method, but which has approximately 3 db greater sensitivity.
Cyclotron Oscillators and the Shifting Inter-Dee Ground Surface
Authors: Schmidt F. H. , Jakobson M. J.
Published: February 2005

It is shown that the push-pull mode of oscillation of a conventional two-dee cyclotron can be described in terms of a ground potential surface between the dees. Unbalance in dee voltages arising from changes in capacitance or inductance of one dee system can be interpreted as a shift of the position of the ground surface. The predictions of the theory have been checked experimentally. The effects on a self-excited type of cyclotron oscillator are discussed. The principal value of the concept is that it enables the cyclotron operator to predict easily the electrical implications of a particular adjustment.
A Specimen Heater for Electron Diffraction
Authors: Picard R. G. , Dornfeld E. G.
Published: February 2005

An electric specimen heater for diffraction studies at temperatures up to 1500°F is described. Specimens up to ½-inch square may be heated by the element which fits in the vacuum chamber upon the regular stage of an RCA-Type EMD-2 diffraction camera. The principal problem is the reduction of stray magnetic fields from heater wires to a negligible value. This is achieved by using low current in high-resistance wire and reverse winding the heater coils. Radiation and conduction losses are cut to a minimum by enclosing the heater element in ``LAVA'' except for a window over which the specimen is mounted. Dc power is taken from the power supply for the valving system.
A Neutron-Sensitive Ionization Chamber with Electrically Adjusted Gamma Compensation
Authors: McCreary H. S. , Bayard Robert T.
Published: February 2005

The use of neutron-sensitive ionization chambers for neutron flux measurement in nuclear reactors is discussed along with the limitation in neutron detection range because of the gamma-ray background in which the chamber must operate. Means of extending this range are also discussed and a new type of compensated ionization chamber is described. The compensation adjustment of this new chamber is made electrically rather than mechanically as in prior compensated chambers. The extension in neutron detection range over that of an uncompensated chamber is of the order of two decades. Frequent adjustment of the compensation is not necessary since the drift is small over a long period of time.
Electronic Flowmeter System
Authors: Kalmus Henry P.
Published: February 2005

A flowmeter system is described which gives continuous readings of flow velocity, with a fast rate of response. The ``upstream-downstream'' method is used in which velocity of a fluid is determined by measuring the phase difference between an upstream and downstream ultrasonic wave of, say, 100 000 cycles. The functions of the transmitting and receiving transducers are interchanged at a fast rate, say 100 cycles per second, allowing the use of a synchronous rectifier. In this way, no long time stability of the phasemeter is required so that very small flow rates can be measured. Velocities as low as 0.1 cm/sec were successfully measured. A special commutator switch with very low transfer capacitance and, as an alternative, an electronic switch are described. The transducers used are barium titanate crystals mounted in a manner so that their contact with the fluid is avoided.
A Semi-Automatic Electrical Manometer Designed to Calibrate a Mach-Zehnder Interferometer System for the Recording of Transient Pressure Changes
Authors: Embleton T. F. W.
Published: February 2005

A pressure-sensitive element is described which provides an electrical output proportional to the pressure difference existing on the two sides of the element. By means of an electrically conducting lead in each arm of a U-tube manometer the liquid (mercury) represents the contact point of a potentiometer; under the influence of an applied pressure this contact point is moved electrically. In the application described, the variation of light intensity at a point in the fringe system of an optical interferometer is calibrated as a function of density or pressure changes occurring in one of the interfering light beams.
A Multichannel Pulse-Height Analysis System Utilizing a 35-mm Film Record
Authors: Hunt Warren A. , Rhinehart Wayne , Weber John , Zaffarano D. J.
Published: February 2005

A system is described for obtaining quantitative amplitude distribution data for events which can be displayed as proportional voltage pulses for visual observation on a cathode-ray oscilloscope. The use of a circuit which intensifies the top of each flattened pulse during display permits photographing the events as dots on a moving 35-mm film at rates of 20 000 per sec or greater. An automatic electromechanical ``reader'' is described which will scan the resulting film and produce a printed record of the number of events in each of 100 discrete ``channels'' with an accuracy comparable to the best available from other ``kicksorting'' schemes. A spectrum of over 500 000 events can be recorded on 100 feet of film.
An Electronic Voltage Integrator
Authors: Madey Richard , Farly George
Published: February 2005

An electronic voltage integrator has been used in the magnetic measurements program of the Berkeley Radiation Laboratory since 1948. The device can explore magnetic fields in the range from 500 to 15 000 gauss to an accuracy of better than one percent. The heart of the integrator consists of a direct coupled high gain amplifier that is connected in a ``feedback time constant'' circuit. The amplifier uses the cascode connection, the filament drift compensation circuit of Miller, and an internal positive feedback adjustment for ``infinite'' gain. Some other features of the integrator amplifier include low grid current operation, large linear output range, and provision for adjustment of the input and the output voltages to zero potential when no signal is present.
Achromatic Beam Translation Systems for Use with the Linear Accelerator
Authors: Panofsky Wolfgang K. H. , McIntyre J. A.
Published: February 2005

The beam of a linear accelerator has desirable properties regarding its geometry but frequently contains secondaries produced in the machine and has an unsuitable energy spectrum.

Two systems have been designed which translate the accelerator beam without energy dispersion. In the one system, now in operation, the emergent beam has an ``energy focus,'' i.e., a point at which the initial beam geometry is reproduced independent of energy. The second system is designed to produce a beam translated but otherwise unmodified in geometry, independent of beam energy to the first order.

Both systems permit easy control of energy width and produce a beam free from secondaries.
A Device for Determining Relative Stopping Powers for Natural Alpha Particles
Authors: Ellis R. Hobart
Published: February 2005

A device is described by which the stopping power for polonium alpha particles of thin solid or liquid films can be compared with that of gases. An optical system measures film thickness, and the relative stopping power is inferred from the decrease of range which results when a thin film is inserted across a beam of alpha particles.

The device has been used with polystyrene and acetylene and a relative stopping power of 0.99±0.02 is observed.
Techniques for Processing Thick Nuclear Emulsions
Authors: Stiller Bertram , Shapiro Maurice M. , O'Dell Francis W.
Published: February 2005

Techniques are described for the ``eradication'' and processing of thick electron-sensitive nuclear emulsions, and for handling ``pellicles.'' 400-micron and 600-micron emulsions, eradicated by a method which preserves their sensitivity to minimum-ionization particles, exhibit marked reduction in track distortion, as well as in background. A modified procedure for uniform development of thick emulsions by the temperature-cycling method gives a favorable ratio of grain density to background. Countermeasures against stripping of thick emulsions from their glass base have proved efficacious over a 3-year period.

A stack of emulsions without glass support (``pellicles'') provides a large sensitive volume in which tracks can be readily followed from one layer to the next. The lateral swelling (∼25 percent) during processing, which discouraged the application of this technique, was overcome by the authors [Phys. Rev. 85, 712 (1952)] in 1951. They evolved a successful method for mounting thick, stripped emulsions onto glass after exposure, but prior to processing, so that the pellicles can be developed as ordinary plates. Since then, additional experience has been gained in the application of pellicle stacks to high-energy physics. Our procedures lead to emulsions free from lateral swelling, free from blistering, and characterized by a level of distortion sufficiently low to permit multiple scattering measurement even on fairly ``stiff'' tracks. The advantages and limitations of this technique, its possible applications, details of the mounting procedure, and methods of following tracks from layer to layer are discussed.
Concentration of a Cyclotron Beam by Strong Focusing Lenses
Authors: Shull F. B. , MacFarland C. E. , Bretscher M. M.
Published: February 2005

A pair of strong focusing magnetic lenses has been used to concentrate a part of the external beam from the Washington University cyclotron. The lenses focus the beam at distances up to more than four meters beyond the end of the cyclotron. This produces approximately an eightfold improvement in beam intensity.
A Calorimeter for Rapid Determination of Heat Loss and Heat Production in Laboratory Animals
Authors: Lawton Richard W. , Prouty Lawrence R. , Hardy James D.
Published: February 2005

A rapid calorimeter of the gradient type, suitable for laboratory animals, has been built and tested. A thin gradient layer (0.015-inch woven glass tape) of relatively high thermal conductivity is used to line the walls of the calorimeter. The heat flow rate across the gradient layer is measured by means of 2152 copper-constantan thermal junctions wired in series. With an input of 1 kcal/hour, 83.26 μv output is obtained. Total response time of the instrument together with the animal holder and metabolic equipment in place is of the order of 10–12 minutes. Heat loss by vaporization is measured by electric hygrometer sensing elements. Heat production is determined by a continual analysis of oxygen consumption using a Pauling analyzer. Heat loss, heat production, and rectal, skin, air, and wall temperatures are continuously recorded. Electric and alcohol calibrations and preliminary observations on monkeys are presented. The calorimeter should make possible critical experiments on thermoregulatory mechanisms of animals.
An Electronic Cardiac Defibrillator and Pacemaker
Authors: McCombs Rollin K. , Herrod Chester E. , Mackay R. Stuart
Published: February 2005

There is described an instrument which has been devised to stop ventricular fibrillation and to restore rhythmical beating of the heart in standstill. The instrument provides 60-cycle sinusoidal pulses continuously variable from 0 to 3 amperes in intensity and from 0.01 to 1.0 second in duration. A single pulse may be delivered for defibrillation, or regularly repeating pulses, from 20 to 120 per minute, may be delivered for instituting rhythmical beating of the arrested heart. The time intervals produced are quite independent of line voltage and tube changes. Suitable provision is made for the protection of the operator from accidental short circuit to ground. Clinical use of the instrument has been restricted to defibrillation, where it has proven successful.
Simple, Automatic, Continuous-Recording Respirometer
Authors: Brown Frank A.
Published: February 2005

A new type of respirometer is described. The method involves a ``diver'' which is composed of a rigid respiratory chamber containing a CO2 absorbent and an O2-containing collapsible sack feeding O2 into the chamber by way of a capillary tube. As O2 is used by the organism in the respiratory chamber, replacement O2 arrives from the collapsible sack thereby decreasing the buoyancy of the system. The change in buoyancy is recorded on a kymograph drum by an ink-recording spring scale. The method has been put in practice using 50 ml Soxhlet distilling flasks with rubber stoppers penetrated by 27-gauge hypodermic needles as the respiratory chamber and sections of Saran tubing (Visking Corporation of Chicago) with an O2 capacity of 40–50 ml attached to the stopper as the collapsible sacks. Recording spring scales with variable ranges from 2 to 20 g which have served satisfactorily for measuring natural variations in rates of O2 consumption for certain small animals are described.
Vortex Burner—A Useful Tool for Studying the Flame Stability of Gaseous Fuels and Fuel Mixtures
Authors: Kurz Philip F.
Published: February 2005

A vortex burner has been developed that permits direct comparison of flame stability of fast-burning and of slow-burning gaseous fuels and their mixtures.

In this burner, air is introduced tangentially into a chamber to generate a vortex. The vortex is then accelerated by means of a converging nozzle which directs the air into a throat section where fuel is injected radially from ports in the periphery of the throat. The flame is stabilized in space in a divergent, pressure-recovery section and burns as a whirling inverted cone.

Flame stability is independent of tangential velocity at any given air rate. However, changes in other parameters, such as throat diameter and length of the pressure-recovery section, do have an effect on flame stability.

The results of these investigations with the vortex burner suggest that further studies with longer recovery sections are of interest. Likewise, the effect of gas temperature on flame stability will be studied.
A Linear Motion X-Ray Spectrometer
Authors: Hanson H. P. , Schrader H. W.
Published: February 2005

A single crystal x-ray spectrometer has been constructed in which the change in Bragg angle is effected through a linear rather than angular motion of the crystal. In certain measurement problems this design offers advantages over the conventional type from a standpoint of versatility and ease of alignment.
The Production of 320-Mev Deuterons by He3 Stripping
Authors: Ise John , Pyle Robert V. , Hicks Donald A. , Main Robert M.
Published: February 2005

Deuterons can be accelerated in the 184-in. cyclotron to 190 Mev. To produce higher-energy deuterons, doubly charged He3 ions are accelerated to 493 Mev, and a fraction of them are stripped in an internal target, yielding deuterons with an average energy of 330 Mev. A current of 5×10−13 ampere is obtained in the experimental ``cave'' external to the cyclotron shielding. Range measurements indicate that these deuterons have an average energy of about 320 Mev.

The high cost of He3 necessitates an efficient gas-recovery system. The exhaust from the cyclotron diffusion pump is passed through activated charcoal traps which are cooled to liquid-nitrogen temperatures, and the gas that is not adsorbed (presumably helium) is returned to the cyclotron source. The loss from all causes is 0.8 cc/hour.
Absorption Spectroscopy of Explosions
Authors: Hanst Philip L. , Myerson Albert L.
Published: February 2005

The Norrish-Porter flash technique of ultraviolet spectroscopy has been adapted to the study of explosions induced by the thermal energy of the reacting gases at the temperature of mixing. The light emitted by the reacting gases during the induction period is used to actuate the flash source by means of a phototube and its associated electronic circuit. The concentrations of free radicals and other short-lived molecular species can be studied as a function of time.
A Reflection Goniometer for the Microscope
Authors: Rankin Bayard
Published: February 2005

An instrument is described which measures angles accurately and rapidly under the microscope. A mathematical model displays the principles involved. It is shown that accuracy is achieved with an ``optical lever arm'' which moves when the eyepiece rotates, the arm's being comparable to a 25-cm mechanical arm attached to the outside of the eyepiece. Rapid measurements are possible by the reading of relative positions of the ``optical arm'' on an illuminated scale which appears superimposed over the microscope field of view. The design and limitations of a practical, working instrument are discussed.
The University of Washington Sixty-Inch Cyclotron
Authors: Schmidt F. H. , Farwell G. W. , Henderson J. E. , Morgan T. J. , Streib J. F.
Published: February 2005

The new constant frequency 60-inch cyclotron at the University of Washington is described. Its principle mechanical features are the following: (1) A 20-inch diffusion pump is placed close to the vacuum chamber in order to provide high pumping speed; (2) The rf conductors are almost free of unsoldered joints in order to provide a high ``Q'' circuit; (3) The positions of the shorting ``spiders'' can be readily changed without breaking the vacuum; (4) The dees and dee stems are removable as one unit from the vacuum envelope; (5) The cyclotron vacuum chamber is constructed of welded aluminum alloy in order to reduce accumulated radioactivity; (6) A unique side-loading target chamber can be used for ordinary bombardments without disturbing apparatus more remote from the cyclotron; (7) The exit strip and other parts of the dee system subject to beam erosion are made of graphite.

The oscillator uses a single ML-5681 tube in a grounded-grid self-excited circuit. A 2-kw frequency-modulated booster oscillator drives the main oscillator above the ``multipactoring'' threshold. A cathode bias resistor is used in place of the familiar constant-current network. Ions are drawn out of the dees by means of a dc-biased rf deflector. Four degrees of freedom of the deflector are adjustable from the console.

An account is given of the major troubles encountered and the steps taken to achieve satisfactory operation. The cyclotron produces external beams of 125 to 200 μa at a nominal deuteron energy of 21 Mev with an oscillator power input of 100–125 kw.
An Electric Field Meter with Extended Frequency Range
Authors: Smith L. G.
Published: February 2005

The frequency range of a field meter of the field mill type has been extended by applying a system of balanced modulation. This is achieved by incorporating two complementary sets of stators. The amplified signals from the stators are detected in a clamping circuit. In the instrument which is described, the frequency range extends to 22 kcps although the modulation frequency is 120 cps.

The method by which the frequency range has been extended can be adapted to other instruments employing mechanical modulation.
The Radio-Frequency Fine Structure of the Photon Beam from the Berkeley Synchrotron
Authors: Madey Richard , Bandtel Kenneth C. , Frank Wilson J.
Published: February 2005

The full energy spread-out bremsstrahlung beam of the Berkeley synchrotron was shown to be emitted in sharp bursts with the 47.7-Mc/sec frequency of the electrons in the doughnut. A two-counter telescope, located about 20 inches away from a one-fourth inch thick lead target and about 20 degrees from the photon beam direction, was used to measure an accidental coincidence counting rate as a function of the length of delay line in one input to the coincidence circuit. When the length of delay cable was chosen equal to integral multiples of the period of the radio-frequency oscillator, the coincidence counting rate was of the order of 100 counts per unit of integrated beam; on the other hand, when the length of delay line was chosen to be equal to one-half of odd integral multiples of the period of the radio-frequency oscillator, the coincidence counting rate was less than about two counts per unit of integrated beam.

An estimate of the width of a single pulse of photons can be obtained from the measurement by unfolding a Gaussian resolution function of the coincidence circuit. If the time variation of the intensity of the photon beam is assumed to be a Gaussian function, then the rms value of that Gaussian is found to be less than 1.5×10−9 second.

A calculation by Lloyd Smith indicates that the measured radio-frequency fine structure should provide a rather accurate picture of the phase-stable bunch of electrons at the end of the acceleration period.
Mechanical Analog Computer for Reading Electron Diffraction Patterns
Authors: McMillan W. R.
Published: February 2005

An instrument, employing the principle of a slide multiplier, has been constructed for reading electron diffraction patterns and computing the corresponding crystal lattice spacings. The constant of the electron diffraction camera can have a value of from zero to 5.000 A cm, and the instrument can record ``dhkl'' spacings from 0.600 to 7.000 A. These spacings are printed, together with estimated line intensities, on adding machine paper. The instrument decreases the possibility of accidental error in copying numbers, and also eliminates considerable fatigue when many patterns have to be read.
Two Ion Sources for the Production of Multiply Charged Nitrogen Ions
Authors: Jones Royce J. , Zucker Alexander
Published: February 2005

Two ion sources have been developed for the production of milliamperes of N+, N2+, N3+, and N4+ ions. Under good operating conditions, 28 ma of N3+ and 10 ma of N4+ are produced. Details of source construction are given and a method for analyzing the source output is presented. Characteristics of both sources as a function of arc current and arc voltage are investigated.
A New Apparatus for the Partitioning of Expired Air of Small Animals
Authors: Palm Paul E. , Cook Kenneth M. , Brown Jack H. U. , Hatch Theodore
Published: February 2005

A mechanical respirator with synchronized respiratory partitioning valve for guinea pigs is described. This apparatus is used for the separate determination of dust retention in the upper respiratory tract and deep lung spaces. The partitioning valve separates the exhaled air into three fractions beginning with the earliest portion of upper respiratory air and continuing to the terminal fraction of deep lung air. The same volumetric fractions from successive exhalations are collected over a test period of any practical duration. In principle, the apparatus is similar to one previously described (Rev. Sci. Instr. 22, 81, 1951) for the study of dust retention in human lungs.
A Stable Wide-Range DC Amplifier
Authors: Offner Franklin F.
Published: February 2005

A versatile high-gain dc amplifier for biological applications is described. Its features include differential push-pull operation with a rejection ratio greater than 1000; response from zero to beyond 30 kc with a maximum gain of about 2.5×106; optional control of high- and low-frequency cutoff (the dc gain can be reduced to 1 percent of the mid-band gain). For applications requiring exceptional stability, an automatic rebalancing circuit is provided which resets the zero of the amplifier at intervals of about 5 seconds. The equipment is ac-operated.
Regenerative Deflection as a Parametrically Excited Resonance Phenomenon
Authors: Barden S. E.
Published: February 2005

The phenomenon termed regenerative deflection is treated as a resonance mechanism forming only one of a larger class of similar mechanisms. Conditions of optimum coupling to promote the growth of radial oscillations are described, and the results of some numerical calculations are given. The causes of the axial spreading of the beam during the extraction period are analyzed, and methods of reducing such spreading are discussed. An electrodynamic system for creating the coupling inhomogeneities is also described.
Shorting and Field Corrections in Hall Measurements
Authors: Flanagan W. F. , Flinn P. A. , Averbach B. L.
Published: February 2005

A method is given for correcting the measured Hall voltage for shorting by the current contacts and for inhomogeneities in the applied magnetic field. This method is applied to measurements of the Hall coefficient in gold-silver alloys.
A Laboratory Arc-Melting Furnace
Authors: Nielsen Morris L. , Johns I. B.
Published: February 2005

Using a glass resin kettle as enclosure, and an inverted-J electrode, a small arc-melting furnace was designed for conveniently melting metals under an inert atmosphere.