bluuebunny/crossref_metadata_2025 huggingface dataset:
A Thermal Gradient Method for the Study of Crystal Structure and Its Application to Order-Disorder Research
Authors: Newkirk John B.
Published: February 2005

A new method has been developed for studying the effect of temperature on the crystal structure of metals and alloys. In this method, a long wire specimen is held for a desired period of time in a known thermal gradient and is subsequently quenched and examined at room temperature by x-ray diffraction. A special x-ray camera is used, by means of which any point along the length of the specimen can be irradiated. The diffracted rays are registered on a cylindrical film in the usual way. This technique offers substantial savings in treating time and has the advantage of subjecting the specimen to all temperatures within the range of treatment.

The method has been applied to the study of ordering phenomena in several binary systems. Debye-Scherrer evidence for the existence of divariant equilibrium between ordered and disordered phases, has been found in several alloys of nonstoichiometric composition. A study of the copper-gold system has yielded data which allow the quantitative location of the (order+disorder) field boundaries near CuAu.
Instrumentation and Experimental Procedure for Studies of Electron Ejection by Ions and Ionization by Electron Impact
Authors: Hagstrum Homer D.
Published: February 2005

Four different instruments are described in this paper. Three have been or are being used in studies of electron ejection from metal surfaces by positive ions. A fourth has been used in the study of the ion optics employed and in studies of ionization and dissociation of diatomic molecules by electron impact. Basic design features and performance characteristics are discussed with particular emphasis placed upon the steps taken to assure proper ion-beam characteristics at the final focus. Experimental procedures are also described among which those having to do with the vacuum and adsorption of gas on the target are considered to be especially important. Auxiliary apparatus and the determinations of contact potential and work function are discussed briefly. The interpretation of data obtained with these instruments is also examined.
Electric Hygrometer of Small Dimensions
Authors: Brastad W. A. , Borchardt L. F.
Published: February 2005

An electric hygrometer of the Dunmore type has been constructed so reduced in size as to fit inside the end of a hypodermic needle. A special indicating circuit is required because of the small current permissible across the hygroscopic film. Relative humidities associated with surfaces as small as 0.001 square inch have been measured.
On the Use of X-Ray Film for the Quantitative Measurement of Diffraction Line Intensities
Authors: Beu Karl E.
Published: February 2005

The use of x-ray film for making quantitative measurements on diffraction lines or peaks is limited primarily by its granularity. The granularity characteristics of two typical commercial x-ray films were examined in terms of microphotometer records to help determine optimum conditions for detecting and measuring the intensities of small diffraction peaks as well as resolving the peaks. A criterion is suggested which relates film development conditions and film speed with the microphotometer scanning area required on the film in order to obtain these optimum conditions. Using this criterion, peak intensity measurements can be reproduced to about ±1 percent and integrated intensities to ±½ percent, or better.
Improvements in Design and Construction of Quartz Helix Balances
Authors: Ernsberger F. M. , Drew C. M.
Published: February 2005

The methods previously used for drawing quartz fiber and winding the fiber into helical springs may be considerably simplified by using a machinist's lathe for both operations. This makes available all the necessary mechanical motions, without constructing special units for the purpose. Fiber may be drawn uniformly to any predetermined diameter between 1.6 and 10 mils and wound with any desired coil diameter and pitch.

In the section on helix design, the performance of a helical balance is analyzed quantitatively in terms of its sensitivity, load capacity, and loaded length. It is shown that an optimum relationship exists between these characteristics, and a method is developed for specifying the dimensions of the helical balance which will give optimum performance in a given application.
Harmonic Synchronous Rectification in Double-Beam Photometry
Authors: Oberly J. J.
Published: February 2005

The properties of linearity and phase discrimination of synchronous rectifiers have been widely used in photometry and other electronic applications. A third property—discrimination against harmonically related frequencies—can be used to improve the separation of signals heretofore accomplished by phase discrimination. The principle is analyzed with particular reference to double-beam photometry, and data obtained by modifying an existing double-beam photometer are reported. Harmonic synchronous rectification should be especially useful when only very little ``cross-talk'' can be tolerated or when the relative phase of signals and rectifiers cannot be maintained conveniently with the accuracy demanded by the single-frequency system.
Range-Energy Relations for Alpha-Particles and Deuterons in the Kodak NTB Emulsion
Authors: Gailar O. , Seidlitz L. , Bleuler E. , Tendam D. J.
Published: February 2005

Range-energy relations for alpha-particles (3–18 Mev) and deuterons (2–9 Mev) in the Kodak NTB emulsion have been determined. Natural alpha-emitters and particles accelerated in the Purdue University cyclotron were used. Cameras for use with the cyclotron and with Po and Th sources are described. In the energy interval investigated the ranges in the NTB emulsion are practically identical with those found in the Ilford B1 and C2 emulsions. They agree also with the ranges previously reported in dry Kodak NTA emulsion but are as much as 10 percent shorter than those reported for the latter emulsion when exposed under ``ordinary'' humidity conditions.
A High Sensitivity Fission Counter
Authors: Baer William , Bayard Robert T.
Published: February 2005

The design and performance of a sensitive rugged fission counter is described. The counter detects thermal neutrons by means of U235 fission. The sensitivity of the counter is 0.7 count/neutron·cm−2 for a background counting rate of 5 counts/sec. The useful range is 10 to 2×105 neutrons/cm2·sec, and the counter will operate over this range in the presence of 1010 gamma rays/cm2·sec.
A Vacuum Lock for Routine Solid Analyses with a Mass Spectrometer
Authors: Stevens Charles M.
Published: February 2005

A vacuum lock for rapid introduction of solid samples into a mass spectrometer is described. Analyses of the highest resolution requiring high vacuum can be made in five to ten minutes following the introduction of the sample. With an analysis time of about one hour using a surface ionization type of source, six to eight samples can be run in an eight-hour day. The unit is incorporated in a 12-in. 60° mass spectrometer.
A High Transmission Slow Neutron Velocity Selector
Authors: Dash J. G. , Sommers H. S.
Published: February 2005

A high intensity neutron monochromator for the subthermal energy region is described. The instrument utilizes the velocity selectivity of a rotating helix. A complete analysis is made of the instrument resolution for several practical constructions. For wavelengths longer than one angstrom, a mechanical selector may yield resolutions of 1.0 to 0.1 and fractional transmissions of 60 percent. Design and tests of a selector are described and compared with the theory.
A Barometer Element for Radio-Sondes
Authors: Neher H. V.
Published: February 2005

The barometer unit described herein has proven to be extremely reliable when used on balloon flights to high altitudes. It consists of an aneroid element which moves an arm, making a series of contacts with no mechanical amplification involved. Working on the digital principle it gives its information when certain definite pressures have been reached.
An Automatic Ionization Chamber
Authors: Neher H. V.
Published: February 2005

The ionization chamber described herein has the following characteristics: 1. It recharges itself after having collected a definite charge. 2. It generates a pulse at the instant of recharging that is easily amplified electronically. 3. The constant of the ionization chamber is independent of the constants of vacuum tubes but does depend on the constancy of a quartz fiber, the pressure of the gas, and the potential of the charging battery. It has been successfully used to measure cosmic-ray ionization at balloon altitudes both in the United States and in northern Greenland.
A Recording Mercurial Manometer for the Pressure Range 0–760 mm of Mercury
Authors: Svec Harry J. , Gibbs Dale S.
Published: February 2005

A recording mercurial manometer which covers the range 0–760 mm of Hg is presented. A Nichrome V or Chromel A resistance wire is concentrically positioned in the mercury column of a large bulb manometer. The resistance of this wire is part of a direct current bridge circuit with a recording potentiometer as the balance indicating device. An electrical circuit which is designed to handle a variety of experimental conditions is presented.
A High Speed Product Integrator
Authors: Macnee A. B.
Published: February 2005

A method of employing the components of a high speed analog computer to evaluate product integrals is presented. Kernel functions of two variables are obtained with time as the variable of integration and the position of ganged potentiometers as the parametric variable. High speed multipliers, function generators, adders, and integrators permit the evaluation of a one-hundred point product integral curve every 1.67 seconds. This curve is displayed on a cathode-ray tube screen having a long persistence P-7 phosphor. Examples of sine and cosine transforms evaluated with the product integrator are given. The observed errors range from 1 to 10 percent, depending upon the problem.
The Cockcroft-Walton Voltage Multiplying Circuit
Authors: Everhart Edgar , Lorrain Paul
Published: February 2005

The conventional Cockcroft-Walton voltage multiplying circuit is studied considering it as a transmission line. It is shown that, even when no direct current is drawn from the high voltage electrode, there is an important loss in output voltage caused by circulating currents in the stray capacitances. This loss of voltage is independent of the supply frequency. Formulas are developed for the voltage efficiency resulting from a given choice of capacitor size and number of stages.

Two modifications of the Cockcroft-Walton circuit which improve the voltage efficiency are suggested and analyzed. The first of these involves a loading coil at the high voltage end of the line. The second involves the addition of inductors in series with each of the capacitors of the circuit.
An Automatic Controller for Radiofrequency Induction-Heating Units
Authors: Theron J. J.
Published: February 2005

A simple, rugged, and adaptable device for regulating the power provided by an industrial rf generator for induction heating is described. An rf voltage picked up by a small coil near the work coil is rectified, opposed by an adjustable dc reference voltage, and the difference-voltage fed to a commercial chopper-type dc amplifier and servo motor. The motor drives the power-controlling element of the generator in such a direction as to reduce the error signal to zero. Regulation of temperature within ±½ degree at 1000°C has been achieved where system is not disturbed in any way.
On the Detection of High Energy Particles with a Fast Coincidence System
Authors: Strauch Karl
Published: February 2005

A coincidence system is described that includes a fast diode bridge coincidence circuit of the type used by Neher. A discussion is given of the properties of such a system that are desired for its use in the detection of particles with a continuous energy spectrum. The adjustment and testing of the system for a given experiment are considered in detail. Finally, the performance of a proton telescope utilizing five fast coincidence channels is described.
The Characteristics of the Synchrotron Beam
Authors: Camac Morton
Published: February 2005

Measurements were made on the characteristics of the synchrotron electron beam at the time of the target irradiation. The orbit of the beam expanded from its synchronous accelerating orbit and irradiated individually a variety of copper targets. There were two sets of measurements. In the first the bremsstrahlung beam intensity was measured. From these data the average number of beam traversals of each target was calculated. In the second set the target was removed from the vacuum system after a bombardment and cut into sections. The induced radioactivity of the individual pieces was measured. Information was obtained on the radial penetration of the target and the radial and vertical oscillations of the beam both before and after the target irradiation. The width of the synchrotron beam was 0.1 inch vertically and 0.14 inch radially. The radial penetration of the target by the primary beam decreased almost exponentially with the intensity dropping by a factor of 2 in about 0.0025 inch.
Direct Measurement of Images in the Electron Microscope
Authors: Froula H.
Published: February 2005

A method and a working model are described for making rapid, moderately accurate measurements of images directly on the fluorescent screen of an electron microscope without the usual intermediate photography. A shadow of variable magnitude is cast over part of the image. By means of an external control, the size of the shadow is adjusted to match the unknown dimension of the image. Calibrations on the control then indicate the magnitude of this dimension.
A Step Wedge for Sensitometry with the Electron Microscope
Authors: Hamilton J.
Published: February 2005

A new method of making intensity-scale electron exposures on a photographic emulsion directly in the electron microscope is described. A microscopic, variable-thickness step wedge for modulating the electron-beam intensity is prepared by a multiple shadowing technique applied to a simple microscopic specimen. An electron exposure through this wedge, in the specimen position of the microscope, gives an enlarged stepped image on the test emulsion which can be read on a conventional densitometer. Comparison exposures are made simultaneously on an emulsion of known characteristics and an unknown test emulsion. Thus, the contrast and the sensitivity of the test emulsion relative to that of the emulsion selected as a standard can be determined quickly and accurately. Also, the characteristics of graininess and sharpness of the test emulsion can readily be evaluated.
An Eighty-Channel Velocity Selector for Neutrons
Authors: Gatti Emilio
Published: February 2005

Sequential switching of the eighty channels of the instrument (each 0.5, 5 or 50 μsec in width) is obtained by photomultipliers coupled to a cathode-ray tube screen.
Absolute Beta-Counting of Gases Containing P-32 Using End-Window Geiger-Müller Tubes
Authors: Rosen Fred D. , Davis Wallace
Published: February 2005

Techniques for absolute beta-counting of corrosive gases containing P-32 have been developed and applied to the determination of the vapor pressure of PF5. Standard, end-window G-M tubes were used; the PF5 was contained in a separate gas cell having an aluminum window and body. Various factors required to convert counting rates to disintegration rates were determined; accuracy of the product of these was evaluated by comparison counting. Absolute activity values that were derived from gas counting data and an equation for the vapor pressure of PF5 agreed with the activity measured from counting solid samples within 1.0 percent. The methods here developed are applicable to other phosphorus compounds as well as to other elements having gaseous derivatives and β-particle energies in excess of 0.5 Mev.
A Low Temperature Bath for Constant Temperature Studies
Authors: Vajda John , Hart Donald P.
Published: February 2005

This article describes the construction and operation of a low temperature bath which the authors used for low temperature impact testing. Its simplicity, economical operation, and close temperature control make it applicable to other uses in the field of low temperature studies.
Nomograms Used in Analysis of Data in the Reaction Li6(n,α)H3
Authors: Boas Mary L.
Published: February 2005

Several nomograms and similar computational devices have been found useful in the analysis and interpretation of data from the reaction Li6(n,α)H3 in photographic emulsions. Three of these are discussed here: (1) a slide rule to determine from measurements on a track with the triton in a small forward cone, what the track length would have been if the triton had gone exactly forward; (2) a nomogram to determine the true alpha-triton angle from its measured projection in the plane of the emulsion; (3) a device for determining, from measurements on a track, the angle between the emulsion and the incident neutron giving rise to the track.
A Thermistor Bridge Correlator
Authors: Anderson Victor C. , Rudnick Philip
Published: February 2005

A circuit is described for the measurement of a correlation coefficient between two continuous signals. The method depends on an accurate mean square element which is obtained through the i2r heating of a thermistor. Relatively simple circuit features give accuracy to about 1 percent, even though the resistance of the thermistor varies by about 25 percent between zero and full input.
The Application of the Laplace Transformation and a Mechanical Harmonic Synthesizer in the Analysis of Electric Circuits
Authors: Schwetman Herbert D. , Brown S. Leroy
Published: February 2005

The purpose of this research was to demonstrate the applicability of a mechanical harmonic synthesizer to the solution of the operational equation related to the analysis of electric circuits. Specifically, the machine has been used to determine the roots of the polynomial in s (the derivative operator) found in the denominator of the equation ik = Ek(s)/D(s). In order to achieve this purpose, the mesh currents of several electric circuits, in which the numerical values of the circuit elements were known, were computed by use of the Laplace transformation method in conjunction with the mechanical harmonic synthesizer. In designing a circuit to demonstrate a specified method, it was observed that the character of the roots of the polynomials could be predicted by use of the facts which follow: 1. For every mesh that consists of R-C elements or R-L elements there is one real root. 2. For every mesh that consists of R-L-C elements there are: a. At least one real root when R/2>(L/C)½; b. Two real roots when R/2 = (L/C)½; c. Two conjugate complex roots when R/2<(L/C)½ where R, L, and C are the effective values of the resistance, inductance, and capacitance of the elements in the mesh.
A High Vacuum High Speed Ion Pump
Authors: Foster John S. , Lawrence E. O. , Lofgren E. J.
Published: February 2005

A vacuum pump based on the properties of a magnetically collimated electric discharge is described. It has a speed in the range 3000 to 7000 liters a second and a base pressure in the order of 10−6 mm.
A Method of Measuring Short Beta-Decay Lifetimes
Authors: Thorn R. N. , Waniek R. W.
Published: February 2005

A new method has been developed for the measurement of short beta-decay life-times using the internal beam of the Harvard 95-inch F.M. cyclotron. Targets are irradiated at different proton energies, and the decaying activities are detected inside the tank by a scintillation crystal-Lucite pipe arrangement connected with a fast recording system.
Low Voltage 14-Mev Neutron Source
Authors: Forbes S. G. , Graves E. R. , Little R. N.
Published: February 2005

A compact accelerator has been built which utilizes tritium targets bombarded by deuterons. A neutron source strength of 108 neutrons per second was achieved. It was possible by using a relatively low accelerating voltage of about 100 kilovolts to arrange the whole assembly so that it could easily be transported from one location to another.
Apparatus for Rapid Determination of Liquid-Liquid and Liquid-Solid Equilibria Involving Corrosive Materials
Authors: Davis W. , Conley L. L. , Rutledge G. P.
Published: February 2005

An apparatus has been built for measurement of temperatures at which phase changes (precipitation of solid or liquid from a homogeneous solution) are visually observed to occur. This apparatus was constructed for use with corrosive chemicals, such as anhydrous hydrogen fluoride, which are contained in a Fluorothene tube. The tube has appropriate thermal shielding and is shaken vigorously to allow relatively large rates of heating and cooling. Precisions of temperature measurement in the order ±0.5°C are attainable.
Instrumentation for Measuring Changes in Phase of Ionospheric Echoes
Authors: Jones Robert E.
Published: February 2005

A method is described for detecting changes in the phase under the envelope of radio pulse echoes reflected from the ionosphere and for making a continuous record of the variations of this phase with time. The system is essentially a frequency convertor, radio-frequency interferometer, and recorder.
Gray Wedge Pulse-Height Analysis
Authors: Bernstein W. , Chase R. L. , Schardt A. W.
Published: February 2005

A photographic method of pulse-height analysis equivalent in performance to a 50-channel electronic analyzer is described. The basic principle is that pulses from the spectrometer amplifier are stretched and then displayed upon the screen of an oscilloscope and photographed through a gray wedge. The experimental error in the determination of counting rates is 5 percent and absolute activity calibration is easily made. The instrument is compact, semiportable, inexpensive, and easy to maintain.
The Determination of Photon Flux for Energies between 150 and 300 Mev
Authors: Edwards P. D. , Kerst D. W.
Published: February 2005

A calorimetric method of determining photon flux is described. Absolute calibration was performed with an improved Pb block calorimeter using thermistors as temperature-sensitive elements. Five-minute irradiations were employed with a maximum of 33 milliwatts emerging from a 0.5-in. collimator placed at 115 cm from the betatron target. A secondary standard was developed for the purpose of determining bremsstrahlung flux. This secondary standard was a 4-in. diameter, parallel plate ionization chamber consisting of a 0.016-in. Al center foil separated by 0.052-in. air gaps from 0.25-in. Cu front and back plates and adapted for use with a Victoreen M-70 electrometer. With corrections described, the results, in ergs/esu per cm air (NTP), are 7340 at 300 Mev, 6370 at 250 Mev, 5720 at 200 Mev, and 5370 at 150 Mev. Calibration of Victoreen thimbles with various types of converter were also made.
Electrometer Triode Follower
Authors: Krakauer Stewart
Published: February 2005

A simple circuit for use in conjunction with electrometer tubes is described. This configuration provides for a reduction in the input capacitance of the circuit to a value in the order of 0.05 (Cgk+Cgp) of the electrometer tube. At the same time linearity is improved. These qualities are achieved through causing both the cathode and the plate potentials of the electrometer tube to follow its grid. No critical compensating adjustments are required. This circuit is particularly suitable as a preamplifier for electrophysiological measurements.
Stereoscopic Cameras for Use with a Wilson Cloud Chamber
Authors: Allen K. R. , Lipsicas M. , Williams W. F. , Fotheringham D.
Published: February 2005

A design of stereoscopic cameras for use in investigating large angle scattering phenomena with a Wilson cloud chamber has been developed. Duplication of projection systems was adopted in order to enable the analysis of tracks to be shared between two teams working simultaneously. It was required that the reprojected images of the two pairs of cameras should be identical to within close limits, in addition to the usual requirements of a high order of accuracy of reprojection of each camera. Tests described in the paper showed that the reprojection was accurate to at least ±0.5 mm, which is within the allowed tolerances of the experiments envisaged. No observable differences were found between the reprojected images of the two pairs of cameras.
A Needle Valve Type of Variable Gas Leak for Mass Spectrometers
Authors: Babelay E. F. , Smith L. A.
Published: February 2005

A high vacuum needle valve may be used as an adjustable leak for regulating the flow rate of gas samples to a mass spectrometer, when the valve is equipped with a wedge and lever system providing very sensitive control of the needle position. Flow through the leak is molecular at spectrometer pressures, but mass flow may be secured by inserting a capillary tube between the sample and the leak. The leak may be closed completely, thereby simplifying the design of the sample inlet system.
Large Thin-Wall Geiger Counter
Authors: Sugihara Thomas T. , Wolfgang Richard L. , Libby W. F.
Published: February 2005

A new thin-wall Geiger counter of large area sensitive to soft beta-radiation has been developed. The sensitive area can be as large as desired and the wall thin enough for C14 (2 mg/cm2). The cylindrical geometry renders the counter especially suitable for accurate assays of large solid samples of low specific activity and low energy.
Membrane Apparatus for Analogic Experiments
Authors: Schneider Paul J. , Cambel Ali B.
Published: February 2005

This paper describes a membrane apparatus which has been used successfully in obtaining analogic soap-film solutions to boundary-value field problems in which either the Poisson or the Laplace partial-differential equation must be satisfied.
An Improved Fast Scaler
Authors: Schoenwetter H. K.
Published: February 2005

A fast scale of four has been developed in which the emphasis has been on reliability. Since the scale of two units employ diode clamping to limit the plate and grid voltage excursions, the most important requirements are (1) proper choice of grid clamping voltages, (2) the grid swing without grid clamping should be considerably larger than and symmetrical about that obtained with grid clamping. To satisfy these and other requirements, metallic film precision resistors are used extensively, and the critical bias voltages are controlled by compensating networks. The resolving time for 3 or more evenly spaced trigger pulses is about 0.06 microsecond. Pulse heights ranging from 6 to 15 volts may be used.
The Electronic Complex Plane Scanner
Authors: Ragazzini John R. , Reynolds Gibson
Published: February 2005

The electronic complex plane scanner is an electronic analog computer which scans the complex plane electrically by running a point along the imaginary axis. By so doing, the magnitude of a system function represented by its poles and zeros is obtained. This is accomplished by multiplying ac voltages representing the distances from the poles to the running point, multiplying the distances from the zeros to the running point, and then dividing the latter product by the former product. This process is mechanized by means of logarithmic networks. By adding a real perturbation to the path of the running point, a perturbation of the magnitude of the system function results. The latter perturbation is shown to be proportional to the phase slope. The computing process is done at a high speed so that it is possible to devise various types of oscillographic displays. One form in which both magnitude and phase slope are simultaneously displayed as a function of frequency is described in this paper.
An Instrument for the Production of Microelectrodes Used in Electrophysiological Studies
Authors: Alexander J. T. , Nastuk W. L.
Published: February 2005

The membrane potential of single muscle fibers may be measured using an internal microelectrode of tip diameter less than 0.5μ. Previously such microelectrodes could only be prepared manually and this method has certain disadvantages. The problem has been overcome through the use of an instrument for which details of design, construction, and operation are given. In principle, a 35-mm length of Pyrex tubing of outside diameter 2 mm and inside diameter 1.3 mm is heated from a surrounding electrically energized platinum coil. At the start, 100-g force is applied to the tubing in the longitudinal direction by means of a solenoid and plunger arrangement. As the tubing softens its length is extended by 5 mm whereupon the automatic application of 1700-g force draws the tubing apart thus forming two micropipettes. The dimensions and electrolytic resistance of typical microelectrodes manufactured with the aid of the instrument are presented.
The Measurement of Distortion in Nuclear Emulsions
Authors: Caulton Martin
Published: February 2005

A quantitative study of distortion in nuclear emulsions, based on a method of measuring and calculating distortion to known accuracy, has been made. The method has been applied to a study of variations in fixing washing and drying procedures. Distortion reduction up to one-half was found to occur with the use of a concentrated sodium sulfate hypo solution. The reduction of vertical shrinkage and the use of thicker emulsions also appear to reduce distortion. The method of distortion measurement is accurate to better than 10 percent using sea-level cosmic-ray background tracks as a distortion indicator.
Double Focusing of Charged Particles by a System of Two Magnets with Nonuniform Fields
Authors: Sternheimer R. M.
Published: February 2005

Equations are obtained for the focusing by a system of two magnets with nonuniform fields such that n>0 in the first magnet and n<0 in the second. For each magnet a lens equation is set up, and then the system of the two magnets is itself treated as a thick lens. It is shown that for very large n, there is in general one object distance for which double focusing takes place. The theory is also applied to deflecting systems with moderate values of n, and it is shown that the entrance and exit angles can be reduced to values of the order of 20° even for small deflections (20°) of the charged particle.
The Theory of the Fixed Frequency Cyclotron
Authors: Cohen Bernard L.
Published: February 2005

The theory of the fixed frequency cyclotron is developed and illustrated at each step with numerical results for an example. The conditions for ion transmission with respect to horizontal motion are derived, and it is shown that they are satisfied by all ions in most cyclotrons. A more correct and more complete focusing formula than that found in the literature is derived and used to integrate the vertical motion. It is characterized by a region in which the net force is defocusing causing the ions to diverge exponentially from the median plane.

The theory is applied to find the maximum energy attainable as a function of dee voltage and magnetic field fall-off. The problem of orbital precession is treated quite generally, and equations for calculating the center of curvature as a function of time are derived. Some considerations in the magnetic field design are presented. A proof is given that ions experience strong radial grouping. The effect of ion source ``feelers'' is discussed.
Measurements of Scintillation Lifetimes
Authors: Phillips H. Bruce , Swank Robert K.
Published: February 2005

A pulsed x-ray method for measuring the decay time of luminescence of organic scintillators is described. The design of the x-ray tube and the arrangement of the accompanying electrical apparatus is outlined. Particular care was taken to minimize the time dispersion effect of the apparatus and to increase the pulse size of the scintillation in order that statistical fluctuations would be minimized. The luminescence decay curves for anthracene, stilbene, and diphenylacetylene scintillators are shown.
Molecular Models of Amino Acids, Peptides, and Proteins
Authors: Corey Robert B. , Pauling Linus
Published: February 2005

A set of accurate scale models has been developed for use in studies of the structures of amino acids, peptides, and proteins. Models representing atoms or groups of atoms built from hard wood to the scale 1 in.=1A are connected by a clamping device which maintains desired molecular configurations. These accurate models have been used as substitutes for calculation in investigations of the probable configuration of the polypeptide chain in proteins. Analogous models constructed of rubber-like plastic to the scale 1 in.=2A and connected by snap fasteners are designed for qualitative studies of protein structure.
The Adaptation of the Norelco High-Angle Spectrometer to the Measurement of the X-Ray Diffraction of Fibers
Authors: Irvin Barbara , Breazeale F. B.
Published: February 2005

The use of the North American Philips spectrometer for the radial and azimuthal scanning of the transmitted x-ray diffraction of rayon tire yarns involved a change in the slit system from convergent to divergent, design of a rotating sample holder, a reproducible sample preparation and positioning, and calibration and control checks which guarantee that the x-ray intensity remain constant to ±2 percent as automatically recorded by the rate meter. Typical data are presented and compared with data obtained photographically.
Recent Developments in the Production of Halogen-Quenched Geiger-Müller Counting Tubes
Authors: Clark L. B.
Published: February 2005

Geiger-Müller tubes have been constructed which use visibly transparent nonmetallic electrically conducting films as cathodes. These tubes have the following advantages: (1) a long plateau; (2) no photosensitivity; (3) an almost indefinite operating life; (4) immunity from damage arising from heavy discharges; (5) straightforward filling procedure devoid of any ``passivising'' or saturating techniques; (6) good response to ionizing radiation throughout the length of the counter; (7) freedom from use of critical materials such as copper or stainless steel No. 446 which require special cleaning and polishing procedures.
Apparatus for Crystal Pulling in Vacuum Using a Graphite Resistance Furnace
Authors: Lehovec K. , Soled J. , Koch R. , MacDonald A. , Stearns C.
Published: February 2005

A vacuum furnace is described for use in pulling large single crystals of germanium from a melt. The heating element in this furnace is a resistance heated split graphite cylinder.
A Fast Neutron Coincidence Spectrometer
Authors: Chagnon Paul R. , Madansky Leon , Owen George E.
Published: February 2005

A fast neutron coincidence spectrometer of high efficiency has been constructed applicable to the approximate energy range of 1 Mev to 20 Mev. Design considerations and the working model are discussed.

To illustrate the operation of such an instrument, the line spectra of the gamma-rays from Co60 and of 3.3- Mev D-D Neutrons are presented. Discrimination between gamma-rays and neutrons is obtained by utilizing the difference in the time of flight of the two particles. In conclusion possible improvements are suggested.
An Inexpensive Recording Differential Manometer Suitable for Reaction Kinetics Measurements
Authors: Thomas George R. , Lichtin Norman N.
Published: February 2005

A differential manometer which photographically records pressure as a function of time is described. A fluorescent lamp in conjunction with a simple louver system provides a sharp image of the interface between indicator liquid and gas. The instrument can be used to study reactions whose half-lives range from a few seconds to several hours.
On Energy Resolution with Proportional Counters
Authors: Hurst G. S. , Ritchie R. H.
Published: February 2005

The shape of a proportional counter pulse due to an extended track of ionization is determined, before and after passing through a linear pulse amplifier, for various values of track extension and positive ion collection time. It is found that the maximum height of the amplifier output pulse is essentially independent of the length and orientation of the track in the counter, provided the time of collection of the outermost electrons is not longer than the amplifier time constant.
Construction of a Universal Electron Diffraction Microscope and its Optical Features
Authors: Tanaka Kenzo , Hashimoto Hatsujiro
Published: February 2005

A universal electron diffraction microscope, as we call it, consists of three stage electron lens and two specimen chambers and functions both as an electron microscope and as an electron diffraction unit. This instrument can be used in the following seven ways:

(1) Electron microscope; range of magnification between 800 and 20 000 times can be covered continuously.

(2) Electron microdiffraction unit; electron diffraction pattern characteristic of any small area of a specimen under microscopic observation can be revealed by a switch.

(3) Dark-field electron microscopic image.

(4) High-resolution electron diffraction unit.

(5) Effective camera length of electron diffraction is variable from 0 to 250 cm.

(6) Shadow micrographs of the specimen used in (4) can be directly obtained.

(7) Shadow microdiffraction (probe diffraction); dark-field microscopic image appears in each diffraction spot.

The specimen in the second chamber can be heated at any temperature up to about 800°C and on which two kinds of substances can be evaporated, and this evaporation gun can also be used for charge neutralization.
A Sensitive Respirometer for the Measurement of Rapid Changes in Metabolism of Oxygen
Authors: Connelly C. M. , Bronk D. W. , Brink F.
Published: February 2005

A respirometer used to study the oxygen metabolism of peripheral nerve is described. The theory of its operation and its operating characteristics are given. The respirometer consists essentially of the nerve trunk itself, placed symmetrically across the tip of a polarized platinum microelectrode which is flush with the floor of the chamber. The sides of the nerve are exposed to moist gas of known oxygen content; the top surface of the nerve is covered. The current to the platinum electrode measures the concentration of oxygen in the nerve at the electrode tip. In the steady state the oxygen concentration near the electrode is determined by: (1) the configuration of the system, (2) the oxygen content of the gas phase, (3) the diffusion coefficient of oxygen in the tissue, and (4) the rate of oxygen consumption by the tissue. Starting from the steady state, any change in rate of oxygen uptake may be followed directly during the first 45 to 60 seconds of such a change; during this time the change is equal to the negative of the rate of change of oxygen concentration at the electrode tip. Slow, prolonged changes in respiratory rate may be followed, within limitations determined by the diffusion characteristics of the system and by slow drift in electrode calibration. It is estimated that changes in rate of oxygen uptake as small as 0.3 mm3 O2/cc hr (0.6 percent of the rate of uptake by resting frog nerve) can be reproducibly detected.
A Micro Glass Electrode for Continuous Recording of Brain pH in Situ
Authors: Sonnenschein R. R. , Walker R. M. , Stein S. N.
Published: February 2005

To measure pH of brain and other tissues in situ, a micro glass electrode in capillary form was devised. The technique of fabrication and characteristics are described. Performance in the brain of the cat is briefly discussed.
An Electrical Analog for Analysis of Compartmental Biological Systems
Authors: Brownell G. L. , Cavicchi R. V. , Perry K. E.
Published: February 2005

An electrical analog for analysis of compartmental biological systems is described and the theory discussed. Biological models may be simulated by an electrical network, and voltage curves from five of the six compartments may be observed simultaneously on the face of an oscilloscope. These voltage curves bear a scale relationship to the specific activity curves of the biological model. Applications are discussed.
The Cosmotron—A Review
Authors: Blewett M. Hildred
Published: February 2005

A description of the Brookhaven Cosmotron is followed by a resumé, component by component, of its design. The necessary dovetailing in the construction is outlined in a chronology of the fabrication, assembly, and testing of the units. A summary of the preliminary operation of the accelerator includes injection and acceleration tests. In an appendix, figures on personnel are included with a table of the basic parameters of the Cosmotron.
Magnet. Part II—Magnetic Measurements
Authors: Green G. K. , Kassner R. R. , Moore W. H. , Smith L. W.
Published: February 2005

Techniques have been developed for the precise measurement of magnetic field shapes of both steady-state and time-varying fields. A series of measurements was used to refine the design of the Cosmotron magnet and to examine the effects on field shape of many parts of component equipment. Measurements of the fields of the Cosmotron magnet have been made in detail; they indicate a field shape that conforms to the design requirements. Measurements on the magnet show good agreement with model predictions.
Magnet. Part IV—Testing Program for the Individual Blocks of the Magnet
Authors: Blewett M. H. , Kelly J. M. , Moore W. H.
Published: February 2005

The 288 blocks that constitute the Cosmotron magnet were tested, individually, to determine their magnetic characteristics. These measurements were used to arrange the blocks in an order that would minimize azimuthal harmonics. The remanent field was the only magnetic parameter that showed appreciable deviations.
Magnet. Part V—Coil
Authors: Kosh J. A. , Livingston M. S.
Published: February 2005

The exciting winding of the Cosmotron magnet contains 48 turns that carry a peak current of 7000 amp. The design, particularly of the special construction required at the ends of the magnet quadrants, is described. The sequence of processes is enumerated for the fabrication and assembly. After preliminary shakedown, periodic tests have shown no leaks to date.
Magnet. Part VI—Power Supply
Authors: Green G. K. , Shelton E. E.
Published: February 2005

The power for the Cosmotron magnet is supplied by a 1750-hp 13 800-volt induction motor that drives a 21 000-kva 12-phase ac generator and a 43-ton flywheel, rotating at approximately 900 rpm. The generator output is rectified through 24 double-grid ignitrons which also act as inverters returning most of the magnetic energy of the coil to the rotating set.
Pole-Face Windings. Part I—Design
Authors: Blewett J. P. , Blewett M. H. , Moore W. H. , Smith L. W.
Published: February 2005

At fields over 10 000 gauss the effects of saturation in the Cosmotron magnet cause deterioration of the field pattern which rapidly becomes serious enough to cause complete loss of the proton beam. This pattern can be restored adequately up to 14 000 gauss by passing current through single-layer windings on the faces of the magnet poles. Peak correction current required at 14 000 gauss is about 300 amp per radial inch of each winding. The pole-face winding returns are so arranged that the winding is almost completely decoupled from the main magnetizing winding. The windings and their power supplies are in place but are not yet energized. Several turns of the winding are used in a self-powered correction for the distortion of the magnetic median surface at injection fields.
Pole-Face Windings. Part II—Fabrication
Authors: Mede John J.
Published: February 2005

The pole-face windings, for correction of saturation effects in the Cosmotron magnet, were wrapped in Fiberglas tape and then cast in a polyester-resin laminate. The process of fabrication and the materials used for casting are described.
Radio-Frequency System. Part I—Design Principles
Authors: Blewett John P.
Published: February 2005

The Cosmotron rf system must supply a 2000-volt radio-frequency accelerating signal across an insulated gap in the vacuum chamber. During the one-second accelerating cycle the frequency must vary from about 370 kc to 4.2 Mc at a rate determined by the rate of change of the field in the gap of the Cosmotron magnet. Frequency is swept in an oscillator whose resonant circuit includes a ferrite-loaded saturable inductor. The impedance of the gap and its associated shield is maintained by ferrite loading. A description is included of the sequence of control and switching operations in the rf system during a complete Cosmotron cycle.
Radio-Frequency System. Part III—Power Amplifier
Authors: Plotkin M. , Yuan L. C. L.
Published: February 2005

The 2-volt signal from the low-level swept oscillator in the Cosmotron frequency-control system is amplified to 2000 volts, for application at the accelerating gap, by two units. The first, the intermediate-level system, includes the functions of gating and a.v.c. The second, the high-level unit, is a push-pull broad-band amplifier capable of an output of 150 kw. The gap voltage is maintained constant by an a.v.c. system operated from a detector directly across the accelerating gap. Metering, protection, and control techniques are described.
Radio-Frequency System. Part V—Properties of Ferromagnetic Ferrites
Authors: Blewett J. P. , Blewett M. H. , Plotkin M.
Published: February 2005

Ferromagnetic ferrites are used in numerous applications in the Cosmotron. For example, in the accelerating unit over a ton of ferrite is included. During the design of the Cosmotron, much information was required about the various electrical and magnetic properties of ferrites. Since this information was not available, a detailed program of investigation of ferrite properties has been carried out. Results are presented of dielectric properties and of magnetic properties as functions of frequency, dc and ac field strengths, and temperature. A general discussion is included of the behavior of electromagnetic waves in ferrite structures.
Injection System. Part II—Injection Optics
Authors: Cottingham J. G. , Moore W. H. , Rogers E. J. , Turner C. M.
Published: February 2005

The injection optical system, through which the 3.6-Mev proton beam from the Van de Graaff accelerator enters the Cosmotron, consists primarily of a deflecting magnet and an electrostatic inflector in which the beam is deflected through angles of 25° and 30°, respectively. Viewing and detecting mechanisms are available for studies of alignment and ion optics. The ion optical properties of the system have been studied in detail; parameters have been chosen which yield an injected beam, parallel in the horizontal plane and diverging within an angle of 0.003 radian in the vertical plane.
Revision of Gas Scattering Theory
Authors: Courant E. D.
Published: February 2005

Previous estimates of the loss of protons through gas scattering are revised to include effects of scattering through angles large enough for immediate particle loss. In multiple-scattering theory, overestimates of loss may occur through use of the Born approximation. Appropriate corrections are discussed.
The Control System. Part I—Central Control and Wiring
Authors: Green G. K. , Kassner R. R.
Published: February 2005

Control circuits for the Cosmotron radiate from a central control room and master terminal box. Remote control, indication, and protective monitoring of all components are provided on a central control console. Extensive interlocks are necessary to protect equipment. Programming circuits automatically control the sequence of events during the operating cycle. The central control system provides integration of the components of the accelerator into a working entity.
The Control System. Part III—Peaking Strips
Authors: Giordano S. , Green G. K. , Rogers E. J.
Published: February 2005

Precise markers, indicating predetermined magnetic field strengths, are produced by fine, high-permeability, wires in the stray field of the Cosmotron magnet. Control is obtained by regulation of the currents through bias solenoids that surround the wire peaking strips.
The Cosmotron Building
Authors: Stoughton L. D.
Published: February 2005

Three wings house the Cosmotron and its associated equipment, offices for personnel, and design laboratories and shops. The facilities in this building, including the cooling-water systems are described.