bluuebunny/crossref_metadata_2025 huggingface dataset:
An Electrical Computer for the Solution of Linear Simultaneous Equations
Authors: Many Abraham , Oppenheim Uri , Amitsur Shimshon
Published: February 2005

An electrical computer, consisting of coils and condensers, for solving symmetrical simultaneous linear equations is described. It employs the network for diagonalizing matrices already described in two previous papers. The theory of the network, taking into account losses in the coils and errors in adjusting the condensers, is developed. By applying a simple correction to the measured solutions, the errors due to the losses in the coils are eliminated. The accuracy, which then depends only on the accuracy of adjustment of the condensers, is usually a few parts in a thousand.
Very Accurate Measurement of Fringe Shifts in an Optical Interferometer Study of Gas Flow
Authors: Werner Frank D. , Leadon Bernard M.
Published: February 2005

A new means of measuring fringe shifts for certain types of interferograms has been devised, and experimental tests indicate that accuracy of better than one five-hundreth of the fringe separation is possible. The method and tests of its accuracy for a simple case of parallel fringes are described. The method eliminates concern over refraction effects in interferograms of a class of gas flows. Among certain measurements with the interferometer which are expected to be greatly facilitated by use of this technique, is the measurement of the density distribution within a low density shock wave front. Some other applications are suggested.
An Automatic Recording Slide-Back Peak Voltmeter
Authors: Ammerman Charles R.
Published: February 2005

A circuit is described for recording the peak voltage of an intermittent signal. An automatic slide-back voltmeter is used, driven by a motor to reduce speed of response. Advantages of the circuit are illustrated by test measurements.
Experimental Technique Used to Measure Transient Waves through Solids
Authors: Allen William A. , McCrary Clyde L.
Published: February 2005

An experimental technique, based upon the principle of the optical lever, has been used to measure surface oscillations as small as 10μ in amplitude on a thick circular plate, while it deforms under explosive attack. The transient behavior of the plate was determined by means of a long focal-length, sweeping-image camera with a writing speed of 4 mm/μsec. In comparison with the Hopkinson method, the technique yields more information of equivalent, or greater, accuracy. Equations are derived that have been used in the analysis of the experimental data. Experimental results are given as an indication of the precision of the technique.
I. Deflection Constants of the DC Galvanometer at a Specified Damping; II. Improved Solutions of the Unbalanced Bridge Circuit
Authors: Andress Philip M.
Published: February 2005

In Part I derivation is given of the current and emf deflection constants of the galvanometer, and the application is shown of these constants to a short method of calculating deflections at critical damping. An analogous method is also shown for calculating deflections at a specified damping other than critical. Part II includes a presentation and proof of basic formulas with correction factors for calculation of available current or available emf at the galvanometer terminals of the unbalanced Wheatstone bridge and of the current through the galvanometer branch. The applicability of these formulas to the Kelvin double bridge is shown, also their applicability to the single bridge when the unbalance is caused by deviations in more than one arm. Criteria are stated for combining bridge and galvanometer, and a new rule is presented for determining the preferred location of galvanometer and battery in a Wheatstone bridge.
A Machine for Tensile Testing at Controlled Temperatures and Constant True Strain Rates
Authors: Bartholomew E. L. , Krystyan K. J. , Millar D. A. J. , Wulff J.
Published: February 2005

The stress required for the plastic deformation of a metal at elevated temperatures depends on both temperature and strain rate. In order to determine mechanical properties at high temperatures, both these quantities must be known and controlled. Otherwise stress cannot be expressed as a unique function of strain. The machine described in this paper performs short time tensile tests at constant temperature and constant true strain rate. It automatically measures and controls the minimum diameter of a cylindrical specimen which is pulled in a constant temperature furnace. A cam drive establishes the required exponential variation of diameter with time, and, by means of an optical comparator and error-operated servo, the testing machine pulls the specimen at the required rate. Load is determined by measuring the deflection of weigh-bars in series with the specimen. Since true strain increases linearly with time, a true stress, true strain curve can be plotted from yield to fracture.

The information obtainable with this machine should be of considerable value in hot-working research, and will complement that available from creep and stress rupture tests.
Metal Ebulliometers for Vapor Pressure Measurement
Authors: Oliver George D. , Grisard J. W.
Published: February 2005

Apparatus and methods are described for the measurement of the vapor pressure of materials, especially corrosive liquid, over the entire liquid range. The first method consisted of measuring the pressure registered on a mercury manometer by helium, which acted as a buffer between the manometer and a single boiling point tube. In the second method, two metal boiling point tubes were connected to a common pressure system. The boiling temperature of the test liquid in one tube was compared directly with the boiling temperature of water in the other. Pressure values were interpolated from steam tables. The data obtained with both systems were compared with accepted data.
Ethylene and Ethyl Alcohol as Quenching Agents in External-Cathode Geiger Counters
Authors: Chasson Robert L. , MacKnight Merritt L.
Published: February 2005

The manufacturing yield of acceptable external-cathode counters has been found to be 67 percent with ethylene-argon filling and 94 percent with ethyl alcohol-argon filling. Over 90 percent of the tubes that did not perform well with ethylene-argon performed well when refilled with alcohol-argon. A total of 444 counters enter into these statistics. Twenty rejected ethylene tubes were alternately refilled and tested with alcohol-argon and ethylene-argon. Results of several of such test cycles showed repeated success with alcohol and failure with ethylene. Deterioration of quality with counting-age was extremely nonuniform for ethylene tubes, and at the end of their useful lifetime they displayed extreme multiple-pulsing but no serious damage to the plateau slope. A temporary return to normal operating characteristics was observed for these tubes after inactive periods. This behavior is explained in terms of the Paetow effect.
A Betatron Monitor and Integrator
Authors: England R. D. , Ogle W. E.
Published: February 2005

A monitor and integrator for use with a betatron are described. Both instruments are based on scintillation type detectors, using 931-A photomultipliers. The monitor presents the filtered output current of the photomultiplier directly on a microammeter. The integrator charges a capacitor with the output of the photomultiplier, fires a thyratron at a preset voltage level, then recycles. Difficulties in eliminating leakage currents and obtaining a linear response in the integrator are described.
A New External Objective Aperture Centering and Interchanging Device for the RCA EMU Electron Microscope
Authors: Bishop Francis W.
Published: February 2005

A device which quickly interchanges and centers up to seven objective apertures in the electron microscope has been described. It consists of a platinum-iridium, aperture-carrying tongue which may be moved longitudinally and laterally through a sylphon bellows arrangement. The interchanging and centering of an aperture takes only seconds since its position can be observed on the final viewing screen. It is believed that these apertures remain cleaner over a much longer time than in the usual aperture arrangement since they are retracted to a shielded position until actually used and only one of seven apertures is in the beam at any one time. With no aperture in place the entire specimen screen may be scanned at low magnification so that the search for suitable fields is simplified. Then the proper aperture for the degree of contrast desired is moved into place and exposures are made in the usual way. The device has greatly simplified the use of objective apertures in the electron microscope.
A Fourier Analyzer
Authors: McDonal F. J.
Published: February 2005

An analog computer which provides Fourier analyses of transients encountered in seismic research is described. The integral ∫F(t) sinωtdt is evaluated by analog computer elements which perform the generation of the functions F(t) and sinωt, multiply the two functions, and integrate the product. The function F(t) is generated from a variable area recording on film by a photocell and amplifier system simultaneously with the generation of the sine function, sinωt, by mechanical means. Multiplication of these two functions is performed by the potentiometer method, and integration is accomplished by servo integrators The instrument also includes control and calibration equipment which facilitates rapid and accurate analyses.
An Improved “Lock-In” Amplifier
Authors: Cox Henry L.
Published: February 2005

An improved “lock-in” amplifier or synchronous switch is described. A sinusoidal reference voltage drives a square-wave generator, the output of which is applied to the anodes of a pair of diodes. The input is applied to the cathodes of the pair of diodes. The dc voltage developed between the two cathodes is observed on a vacuum-tube voltmeter. This dc output voltage is directly proportional to the signal voltage, and is, to a large degree, independent of the general noise level at the input, the reference voltage amplitude, and the tube parameters.
A Method of Control of a Predetermined Flow Rate
Authors: Reamer H. H. , Sage B. H.
Published: February 2005

The accurate control and determination of small rates of displacement of fluids are of interest in many experiments. Such problems are of particular importance in nonequilibrium investigations involving diffusion, flow of fluids, and other studies in which time is a primary variable. A relatively simple device for the predetermination and control of the rate of displacement of fluids at atmospheric and elevated pressures is described. It is believed that the rate of displacement may be maintained at a prescribed value with an uncertainty of not more than 0.05 percent and the error in the actual value of the rate is not more than twice as great.
Methods of Obtaining High Vacuum by Ionization. Construction of an ``Electronic Pump''
Authors: Schwarz Helmut
Published: February 2005

Calculations on the possibility of obtaining high vacuum in an electrical discharge are given. It is shown that in a simple dc gas discharge practically no real pumping action is possible; in such a discharge only clean-up, i.e., electrical adsorption, may be observed. A real pumping action only results if it is possible to get within a tube, such a high ion current by special arrangements that the number of ionized gas molecules transported with this current in one direction is greater than the number of gas molecules that will diffuse back in the opposite direction. An electronic high vacuum pump of real pumping action has been built; it starts pumping at about 10−3 mm Hg and gives an ultimate pressure lower than 5×10−6 mm Hg.
Evaluation of Particle Loss Due to Multiple Scattering in Foils
Authors: Dickinson W. C. , Dodder D. C.
Published: February 2005

A graphical integration method is described for the determination of the fraction of a parallel beam of charged particles which is scattered out of a detector when a foil is interposed before the detector. For the case of circular foils and detectors with common normal axes a generalized graph of percentage particle loss is given which illustrates that, although the loss may be quite large, rather small variations of the experimental parameters can greatly reduce it.
An Improved Historadiographic Apparatus
Authors: Clemmons J. J. , Aprison M. H.
Published: February 2005

An instrument is described for quantitative historadiography, a method whereby the mass of biological structures as small as one micron in diameter can be determined. The improved apparatus enables ten historadiographs to be taken within an hour. The versatility of the apparatus and the ease of operation suggest a wide application for its use in pathology and histochemistry.
Surface Ionization Source Using Multiple Filaments
Authors: Inghram Mark G. , Chupka William A.
Published: February 2005

A new multiple filament surface ionization source has been developed for mass spectrometry which for several of the elements is many times more efficient than the usual single filament surface ionization source. Emission from the source can be shifted from the oxide to the metal position or vice versa by appropriate adjustment of temperatures. Because of the high efficiency of the source it is possible to look at the sample during a number of successive evaporations. Use of this source should eliminate the necessity of using electron multiplier ion detection for some elements.
An Animal Respirator for Use in Electrically Shielded Rooms
Authors: Wing Kempton G. , Dengler Oskar E.
Published: February 2005

A portable respirator is described which operates with a sufficiently low level of noise and electrical disturbance to permit its use with sensitive electronic equipment in electrophysiological studies of the auditory and other systems. It is operated by a plastic shaft passing through the wall of an electrically shielded room to a portable driving mechanism outside. It may be used with room air or other gases without admixture of room air. Respiratory minute volume is fixed for each animal by adjusting the stroke length of the pump and selecting a suitable drive speed. The animal may be placed in any position for access to any part of its body. Dead-space air and rebreathing are determined by the design and timing of a 3-way valve and by the length of tubing from pump to animal.
An Aerosol Analyzer
Authors: Masters Joseph I.
Published: February 2005

Described is a simple device for measuring the total mass and total charge of a powder cloud. The instrument consists of a sensitive electrometer circuit and a metallic collection chamber. The powder is collected on a filter paper sealed between two aluminum tubes which, if their length is three times greater than their diameter, provides sufficient shielding of the charge collected on the filter paper to justify assumption of an ``Ice Pail.'' The shielding error is less than 0.5 percent. A null-reading circuit is used with a Cenco electrometer. The necessary counter voltage for the null-reading circuit is supplied by a potentiometer circuit, and a vacuum-tube voltmeter is used to measure the voltage. Because it is desired to obtain explicitly the mass and charge of a given cloud of particles rather than the ratio of charge to mass, enough mass must be collected for weighing and, in addition, the total charge measured. This is to be accomplished without disturbing appreciably the normal flow rate of powder from the aerosol generator.
Effect of Space Charge on Saturation Properties of Ionization Chambers
Authors: Lapsley A. C.
Published: February 2005

Experiments on cylindrical ionization chambers operating at high-current densities showed that more voltage was required to produce saturation when the central electrode was negative than when it was positive with respect to the outer cylinder. An analysis is made which indicates this phenomenon might be explained by the positive ion space charge. Under the condition of uniform ionization density within the chamber, a relation is developed for the ratio of voltages required to overcome the space charge for the two collection polarities. Also, approximate analyses are made for the cases of the ionizing particles originating at the surface of either electrode. There is only rough agreement between the calculations and experimental data.
A High-Intensity Pulsed Ion Source
Authors: Gow J. D. , Foster J. S.
Published: February 2005

A pulsed cold cathode ion source, giving peak proton currents in excess of one milliampere and average currents up to 50 microamperes, is described. The source is based on the Penning discharge using axial extraction of the ions. Some discussion of the discharge mechanism and the role of the cathode material is included. Installation and operation of this source in the Berkeley 4-mv Van de Graaff and its performance in that machine is discussed.
A Pulsed Mass Spectrometer with Time Dispersion
Authors: Wolff M. M. , Stephens W. E.
Published: February 2005

An improved design of a pulsed mass spectrometer using linear time of flight analysis has been completed. A peak width of two mass units at mass 40 has been achieved as well as a linear mass scale.
Design and Performance of a Radio-Frequency Ion Source
Authors: Goodwin Lester K.
Published: February 2005

Tests were made on a 27-megacycle, inductively coupled, radio-frequency ion source standardized in design for use at the Los Alamos Scientific Laboratory. Total deuteron beam current and probe current characteristics were found, in tests made before installation, as a function of gas pressure of the discharge, rf power input, probe voltage, and extraction system geometry to determine the best values of these variables to use. These characteristics showed a maximum total beam current of 600 μa to be obtained with roughly 200 watts of rf power input. Tests made after installation in an accelerator gave 92 percent monatomic deuteron beams of up to 80 percent the strength found under similar conditions in the tests made before installation. A platinum-coated envelope gave a triatomic beam of about one-eighth the strength of the monatomic beam obtained with an uncoated envelope. The source has been used at 150-psi external pressure in a Van de Graaff tank.
Apparatus for Nuclear Magnetic Resonance
Authors: Gutowsky H. S. , Meyer L. H. , McClure R. E.
Published: February 2005

Apparatus and procedures are described for the high-resolution measurement of resonance shifts and for the observation of broad line shapes. Included are a discussion of magnet design and a summary of empirical results obtained in the construction and field homogenization of two large permanent magnets. Narrow, complex resonance lines, with components separated by as little as a milligauss, are resolved by a combination of homogeneous applied magnetic field, small samples, and slow-sweep field modulation. Broad absorption line shapes are plotted at fixed frequency by a system incorporating a regenerative oscillator, a narrow band amplifier, a recording potentiometer, and an electronic control for varying the applied magnetic field linearly in time. A simple cryostat provides stable temperatures from 85° to 500°K. In the case of samples with short spin-lattice relaxation times, such as the metals, improved signal-to-noise ratios are obtained by adjusting the oscillator to super-regenerative operation and observing the frequency modulation associated with the dispersive component of the resonance.
A Vacuum Anemometer
Authors: Trevoy D. J. , Torpey W. A.
Published: February 2005

A vacuum anemometer is described for indicating or measuring the streaming of gases and vapors in vacuum. The device is particularly useful for measuring the projective vapor emission from liquid surfaces and the flow of gas through pipes, for instance, between a vessel and a pump. The anemometer consists of a propeller mounted on a shaft supported by jeweled bearings, the propeller being driven by the stream of gas. To measure the speed of the propeller, a small ac generator is incorporated in the device, and the output is indicated by an electronic voltmeter. Under conditions of heavy electrical braking, it is shown that the speed is directly proportional to the pressure, independent of the nature of the gas and of its molecular weight. The instrument is rugged, insensitive to vibration, stable, and readily calibrated. It has low inertia and responds rapidly to a change in the momentum of the stream of incident molecules. Sources of error are discussed and typical performance data are reported.
An Improved Cuvette Densitometer for Cardiac Output Determination by the Dye-Dilution Method
Authors: Gilford S. R. , Gregg D. E. , Shadle O. W. , Ferguson T. B. , Marzetta L. A.
Published: February 2005

This paper is concerned with the development of an improved form of cuvette densitometer used in the measurement of cardiac output by the dye-dilution method.

In this method the output is calculated from the relationship expressing rate of dilution of a dye introduced in the heart as a function of flow rate. The role of the densitometer is that of recording the time-concentration function of the dye in blood. This recording is made as whole blood is led in a continuous flow from a peripheral artery of the subject through the transparent cuvette of the densitometer.

The densitometer to be described is an improvement over previous units in its stability, sensitivity, size, and convenience of application. A complete description of the principles of operation, circuit details, mechanical arrangement, and performance characteristics is included along with recommendations for future improvements.
Magnet. Part III—Mechanical Design, Fabrication, and Erection
Authors: Meyer R. A. , Moore W. H.
Published: February 2005

The mechanical details of the structure of the Cosmotron magnet and its supports are outlined. Details of the manufacturing processes and the final assembly are included.
Radio-Frequency System. Part II—Frequency Control
Authors: Blewett J. P. , Rogers E. J. , Swartz C. E.
Published: February 2005

Frequency control in the Cosmotron is based on a signal derived from a pickup loop in the magnet gap. This signal is integrated electronically and is then distorted in a nonlinear network to yield a control voltage for the saturable-core oscillator. System constants are chosen such that the oscillator frequency has, at all times, the value associated with the instantaneous Cosmotron magnetic field. Dynamic frequency is measured by counting cycles for one millisecond at any desired time during the cycle. Tests on the present system indicate that it is adequate, but that several simplifications are possible.
Injection System. Part I—Van de Graaff Accelerator
Authors: Rogers E. J. , Turner C. M.
Published: February 2005

Protons, for injection into the Cosmotron, are accelerated to about 3.6 Mev in a horizontal, pressurized Van de Graaff accelerator built by the High Voltage Engineering Corporation of Cambridge, Massachusetts. The machine is rated at 4 Mev, peak. A pulsed ion source is included in the high-voltage terminal and is pulsed by an external circuit linked to the ion source through a light beam and photocell. Pulsed ion output includes about 1 ma of protons. The terminal voltage is stabilized to 1 part in 2000 by a servo loop that includes a deflection magnet, split-plate collector, and grid-controlled corona discharge.
Vacuum System. Part I—Vacuum Chamber
Authors: Jacobus D. D. , Polk I. J.
Published: February 2005

Details are given of the design, fabrication, and assembly, of the Cosmotron's vacuum chamber. Four quadrant-length units, each shaped to fit the magnet's curvature, are joined by expansion joints to stainless steel straight-section boxes that house special component equipment. In the quadrant sections, the inner and outer walls are 1-in. thick, solid, low-permeability stainless steel; to minimize eddy currents, the top and bottom parts consist of separated, stainless steel bars. An airtight cover of Myvaseal rubber is stretched over the top and bottom of the complete quadrant section. Tests on other models are discussed; outgassing measurements on several materials are included. Gaskets in the system are Myvaseal, and measurements on its properties and techniques for its use are described.
Variable Field Beta-Ray Spectrometer-Spectrograph
Authors: Katz Robert , Lee Milford R.
Published: February 2005

The design and performance of a high source type, 180° focusing, variable field, beta-ray spectrometer-spectrograph are described. Some details regarding the measurement of magnetic field, the construction of end-window Geiger counters, and the preparation and thickness measurement of thin Formvar counter windows are also discussed.
Wind Tunnel Tests on Seven Aerovanes
Authors: Mazzarella Daniel A.
Published: February 2005

Each of the Aerovanes used on the 420-ft meteorology tower at Brookhaven has been tested in one or more wind tunnels. An equation of motion is defined. Comparisons are offered in terms of the period of each instrument and its damping coefficient. Other comparisons include starting speeds, stopping speeds, and the effects of aging and unbalance on the performance of Aerovane propellers.

The effect of yaw on the readings of windmill-type anemometers has been investigated further. An expression is given for the relationship between true speed, indicated speed, and angular displacement.

The recovery time of an Aerovane propeller from rest can be expressed as a hyperbolic function of speed.
Cyclotron Techniques for Radiation Damage Studies
Authors: Yockey H. P. , Andrew A. , Fillmore F. L. , Glasgow L. E. , D'A Hunt C. , Pepper J. H.
Published: February 2005

This report describes the methods and equipment developed for the irradiation of materials under controlled conditions on the 60-inch Berkeley cyclotron. Descriptions are given of the components of equipment for use in the temperature range from −195°C to 2000°C. These include target boxes which accurately locate the specimens to be irradiated in the cyclotron beam, a cold helium circulating system which is used to cool targets to about −195°C, and a servo temperature controller which automatically regulates the temperature of targets. Typical targets are described along with the conditions of irradiation. The method of determining the spatial distribution of the irradiation intensity is also given.
Apparatus for Measuring Relative Blood Viscosity
Authors: Swank Roy L. , Roth John G.
Published: February 2005

A method for measuring blood viscosity which can be applied to small quantities of blood containing no anticoagulant, and which can be repeated at several minute intervals is described. The method utilized an old principle of measuring time of flow of a fixed quantity of blood (0.1 ml) through a fixed capillary tube (hypodermic needle with a bore approximating 0.3 mm), using a fixed negative pressure of 100 mm of mercury. The needle and pipette which come into contact with the blood are maintained at a temperature of 37°C±0.5°C. The blood is drawn into a 2-ml siliconed syringe through a size 20 siliconed intravenous needle. The calibrated capillary tube is then inserted through the tip of the syringe and negative pressure applied. The time of flow is measured with a stop clock to 0.1 second. Duplicate measurements on the same sample of blood can be made in less than 30 seconds. A high vacuum pump is included with the apparatus to clean and dry the needles and calibrated pipette immediately after each measurement. The relative viscosity of the blood is then computed by dividing the time for flow of 0.1 ml of blood by the time for flow of water at the same temperatures.
Equipotential Plotting Table
Authors: Dahlin E. B.
Published: February 2005

The author has constructed an equipotential plotting equipment of the same principle as used by Murray and Hollway [J. Appl. Phys. 24, 110 (1953)]. The electrolytic field of an ordinary paper with electrodes painted upon it with graphite dispersion is mapped with a probe. The electrodes are fed with dc of 1000 volts. Due to the high resistivity of the paper (about 104 megohms/sq), polarization is of no importance. The position of a desired equipotential line can be found easily with an accuracy of 0.1 mm at an interelectrode space of about 300 mm.

The papers used have proved to have some undesirable qualities that decrease the accuracy unless special precautions are made. The most important errors are the variations of the paper thickness across the surface and the nonisotropic conductivity of some kinds of paper. When measuring currents (the analog for flux) it was necessary to avoid errors caused by the great change of conductivity of the paper at different atmospheric humidity. Normal variations of the humidity proved to change the conductivity by a factor of four.
Photoelectric Comparator for Measuring Oscillograms
Authors: Phillips H. Bruce
Published: February 2005

A device for measuring photographic oscillogram coordinates is described. By means of a photoelectric balancing technique the instrument allows the locating of the ``middle'' of a photographic line with an error of the order of a few microns. The ``middle'' of a line is defined by the instrument as being the point of equal transmission, which is the location on the line at which there are equal amounts of light transmitted on each side. Since the photoelectric comparator is a null device, nervous strain on the operator is greatly reduced.
Operating Characteristics of a High Yield Rf Ion Source
Authors: Eubank Harold P. , Peck Russell A. , Truell Rohn
Published: February 2005

An rf ion source has been constructed, which yields up to 15 ma of hydrogen ion current consisting of 80–90 percent protons. The ion current yield has been studied as a function of rf power and frequency, gas pressure, and dc (extracting) voltage. These relationships are correlated with internal phenomena of the gas discharge and of ion extraction therefrom.
Production of Doubly Charged Helium Ions
Authors: Bittner John W.
Published: February 2005

A 0.6 μa beam of He++ ions has been produced and accelerated to 7.6 Mev in an electrostatic generator. The He++ ion source, contained in the high voltage electrode of the generator, consists of a second small 400 kv electrostatic generator driven by the upper belt pulley of the main machine. He+ ions obtained from a low voltage arc type ion source in the dome of the small generator pass through a region of low pressure gas to become doubly ionized before entering the main accelerating tube of the large generator.
An Electron Current and Energy Regulator for Mass Spectrometer Ion Sources
Authors: Hutchison Dwight A. , Wolff Jay R.
Published: February 2005

An improved electron current and energy regulator for mass spectrometer ion sources is described. The improvements over previous regulator circuits consist of (a) a two kilocycle filament excitation supply which allows improved filament emission control and (b) a method of controlling the filament to shield voltage over a wide range of electron energies. Data on isotope ratio measurements are provided to show the increased stability over that of previous regulators.
Characteristics of an Electron Multiplier in the Detection of Positive Ions
Authors: Barnett C. F. , Evans G. E. , Stier P. M.
Published: February 2005

An Allen type electron multiplier has been studied to determine its feasibility as a quantitative detector of positive ions. Results are presented showing the gain or efficiency as a function of aging, pressure, dynode voltage, and input current. Also, the gain is presented for several positive ions (H+, H2+, He+, N+, Ne+, N2+, A+) in the energy range from 5 to 250 kev.
Quantitative Pole Figures for Sheet Material by the Reflection Technique
Authors: Mueller Melvin H. , Knott Harold W.
Published: February 2005

A method is described for obtaining quantitative pole figures for sheet material by the use of the reflection technique only. Seven different sections of the sample are used for obtaining the data for one quadrant of the pole figure which makes it possible to obtain adequate resolution of very close reflections. One section is prepared from a single piece of the sheet. The other six sections are made up of a number of small pieces of the sheet mounted in a jig in order to form a plane surface at an angle of 45° or 90° to the surface of the sheet. These jigs are mounted on a special table for the modified Schulz reflection specimen holder. Intensity data are obtained automatically for a number of different positions on the pole figure defined by φ and α. The method of plotting this intensity data is shown which results in quantitative pole figures with contour intensity lines.
Efficient, Fast, Energy Sensitive γ-Ray Counters for Use above 50 Mev
Authors: Pugh G. E. , Frisch D. H. , Gomez R.
Published: February 2005

Two energy-sensitive gamma-ray counters which have been used in experiments above 50 Mev are described. One counter uses a low Z scintillating liquid to measure the energy loss of an electron pair; the other uses high Z material to develop a shower which is sampled with scintillating plastic sheets. Curves of the experimental performance are included.
Diffusion of Gases through Nickel and Design of a Convenient Leak for Hydrogen and Deuterium
Authors: Landecker K. , Gray A. J.
Published: February 2005

The diffusion of gases through thin-walled nickel tubing (cathode tubing) has been investigated in the temperature range 200–1000°C. It was found that at the most thoroughly examined temperature of 500°C and at a pressure difference of 1 atmos, hydrogen and deuterium diffuse through this tubing about 2000 times faster than any of the other gases tried. The design of a hydrogen and deuterium leak is described which is easy to construct and to operate. The tubing does not appear to deteriorate because of crystallization as is experienced with palladium tubing.
Two New Electronic Analog Multipliers
Authors: Meyer Maurice A. , Fuller Harrison W.
Published: February 2005

This paper describes two new four-quadrant analog multipliers which have some advantages over other designs which have been reported earlier. A satisfactory balanced modulator which is necessary for both designs is described in some detail. The first multiplier uses a modified double amplitude modulation scheme applying the recent work of Sternberg and Kaufman on the two-frequency modulation product problem. The test multiplier has a frequency response from dc to 30 kc for either input. The accuracy is ±0.5 percent of full scale at full-scale output, and ±0.2 percent of full scale at one-tenth of full-scale output. The dc drift stability of the output is ±0.15 percent of full scale, and the scale factor stability is ±1 percent of full scale over a period of several hours. The second multiplier uses successive phase modulation and amplitude modulation of a carrier. A description of the method and a discussion of error sources are given. The performance of this multiplier is in general inferior to that of the first.
Programming a Digital Computer for Cell Counting and Sizing
Authors: Welkowitz Walter
Published: February 2005

A method is presented for programming a digital computer, used in conjunction with a television scanning system, to count and size solidly and contrastingly stained cells of different shapes and sizes as found on slides prepared for histological study. When the operating times of the program are considered, it is found that machine counting and sizing is very much faster than a manual performance of the same operations. A program prepared in accordance with the method presented operated satisfactorily on the Illiac digital computer.
High-Speed Turbine-Driven Rotating Mirrors
Authors: Buck Willard E.
Published: February 2005

A rotating mirror is the basic element in the highest-speed cameras of both the framing and sweeping image types. The factor of merit of these cameras is determined mainly by the peripheral speed of the mirror. The turbine drive described here will spin the best-quality steel mirror up to its bursting speed. Flat mirrors with faces 17.5 mm wide by 21 mm perpendicular to the rotational axis are operated regularly at 10 000 rps. A camera designed to use these turbines and to take pictures at the rate of 3 500 000 fps, (frames per second) with an exposure time of 0.1 μsec, is illustrated.
A Scintillation Pair Spectrometer
Authors: West Harry I. , Mann L. G.
Published: February 2005

A scintillation pair spectrometer involving the use of three NaI(Tl) crystals has been developed which has a high rejection of all unwanted pulses. As in the usual scintillation pair spectrometer, the gamma rays pass into a center crystal and the pair events are selected by detecting the two annihilation quanta in two side crystals. High rejection of unwanted coincidences is obtained by using a cathode-ray tube differential discriminator set on the photoelectron peaks of the annihilation quanta in the side crystals, along with coincidence circuits of moderately good resolution (0.15 μsec). In this way pair distributions from Na24 (1.38 and 2.76 Mev) and Co60 (1.17 and 1.33) have been observed with almost no background. The apparatus has also been found useful in many other scintillation counter applications involving energy differentiation and coincidence counting.
Detection of 2.5-Mev Neutrons with a Single-Crystal Scintillation Counter
Authors: Segel Ralph E. , Swartz C. D. , Owen George E.
Published: February 2005

The spectrum of pulse heights from a stilbene scintillation counter exposed to approximately monoenergetic neutrons is subject to a number of inherent distortions. It is shown that the neutron energy and intensity can be determined rather simply by proper analysis of the experimental data. The reduction of background by various types of collimation is described.
Image-Converter Camera for Studies of Explosive Phenomena
Authors: Gibson F. C. , Bowser M. L. , Ramaley C. W. , Scott F. H.
Published: February 2005

A single-frame camera is described which uses a pulsed image-converter tube as a shutter to give 10−7-second exposures. The image-converter tube converts an optical image into an electron image and reconverts it into an optical image; gating or deflection in the electron phase is easily accomplished. Circuits and methods for application to single-frame photography of high explosive phenomena are given and representative photographs are shown.
Test Cell for Measuring the Dielectric Strength of Elastomeric Materials in Air
Authors: Reynolds Stanley I.
Published: February 2005

A special test cell using standard ASTM electrodes is described for measuring the dielectric strength of small specimens of elastomeric materials in air, up to a peak voltage of 50 kilovolts. The test cell is constructed so that samples can be measured in a stretched or unstretched state. A dial micrometer automatically measures the thickness of the samples in test position. Results of alternating current tests on GRS electrical grade rubber are given.
A Technique of Soldering to Thin Metal Films
Authors: Belser Richard B.
Published: February 2005

In the past, soldering to thin metal films on glass or quartz substrates has normally been accomplished by suitably reinforcing the film at the soldering point with a thicker underlying film. This performance is necessary in order to prevent tin-lead solders and commonly used fluxes from destroying the film and to give better adhesion to the substrate. It has been found that by using the metal indium and certain of its alloys as a solder, without a flux, adherence to thin metal films may be readily obtained without destruction of the film. Since indium also adheres to glass, quartz, ceramics, and silicious minerals, the strength of the joint is not determined by the strength or adherence of the metal film but by the strength of the indium-glass or indium-quartz bond. Thus, films of only a few angstroms in thickness may be soldered without damage, with good mechanical strength and electrical contact. The strength of the bond is usually about 500 pounds per square inch. This technique has been found most useful in studying the resistivities of thin metal films and in the mounting of metal-coated piezoelectric crystals. Soldered connections have been made to films of 18 metals including aluminum, titanium, and zirconium.
New Instrument for Rapid Evaluation of Time-Displacement Curves
Authors: Maier Karl W.
Published: February 2005

An instrument is described which makes possible universal evaluation of time-displacement records with regard to velocity and kinetic energy, acceleration and accelerating force, time, and displacement. It consists of a measuring device for reading distances, angles, and second derivatives, and a slide rule for direct conversion of the measured values into the desired values. The instrument can be attached to a standard drafting machine of a drawing board. It has many advantages over the present methods of evaluation; no lines need to be drawn on the record, and the instrument permits much more rapid evaluation with fewer errors and can be used by less highly trained personnel.
A Fast-Compression Magnetic Cloud Chamber and Some Auxiliary Control Circuits
Authors: Emigh C. R.
Published: February 2005

The primary considerations which were employed in the design of a cloud chamber for a recent experiment were to incorporate into its characteristics as high a magnetic field strength and as short a cycle time as practical, and a sequencing control circuit which would be both simple to adjust and reliable over long periods of data-taking time. A description is given of the important constructional details of the cloud chamber as well as a discussion of the more important auxiliary circuits. These are: the control circuits for the diesel-driven generator which supplies the current for the cloud-chamber field coils, the pulsed light system for photographic illumination, and the temperature regulating circuit for the cloud chamber.
An Oscillographic Method for Determining Velocities of Detonation in Explosives
Authors: Gibson Frank C.
Published: February 2005

The method and apparatus are described for determining velocities of detonation over one to five adjacent segments of an explosive charge. Time intervals are determined to the nearest 0.1 microsecond, which permits an accuracy of the order of 1 percent where distances of 10 centimeters are employed in 7000 m/sec explosives. Representative data are included to show the accuracy of the method as well as application techniques.
Determination of Heat Capacity by Pulse Heating
Authors: Pochapsky T. E.
Published: February 2005

A description is given of apparatus used to measure the heat capacity of metal wires by pulsed heating. The electrical energy supplied to the wire is determined with respect to a platinum standard while the temperature rise is determined from the change in resistance and the measured temperature coefficient of resistance. A maximum error of 5 percent in the specific heat might be expected with the apparatus as built, but the results agree with most published data to within a few percent in the range 0°C to 650°C.
Electron Transit Times in Geiger Counters
Authors: Heirtzler James R.
Published: February 2005

The transit time of an electron between the cylinder and the central wire of a self-quenching Geiger counter has been measured as a function of several counter parameters. The partial pressure, total pressure, and nature of the filling mixture were varied. The measured times are presented in graphic form.
An Apparatus for the Determination of the Solidus Temperatures of High-Melting Alloys
Authors: Oriani R. A. , Jones T. S.
Published: February 2005

An apparatus has been developed for the determination of the melting temperatures of alloys up to 2200°C, which attains blackbody conditions for the temperature measurements and precludes the possibility of contamination from a refractory container. Its operation has been checked by melting gold, nickel, iron, titanium, platinum, zirconium, and rhodium with an average reproducibility of ±5° and an average deviation from the recognized melting points of 5°C. The melting point of pure vanadium has been determined as 1919±2°C.
Measurement of Angular Distributions of Nuclear Reaction Products with an Internal Cyclotron Beam
Authors: Cohen B. L. , Neidigh R. V.
Published: February 2005

Angular distributions of elastically-scattered protons, and of deuterons, tritons, and alpha particles from (p,d), (p,t), and (p,α) reactions are being measured with the internal 22-Mev proton beam of the Oak Ridge National Laboratory 86-in. cyclotron. The particles are detected by observing the activities induced by them—Cu(p,n)→38 min for protons, Pb(d,p)→3.3 hr for detuerons, Co(t,p)→1.6 hr for tritons, and P(α,n)→34 min for alphas. Energy discrimination is obtained by absorbers. The energy and energy distribution of the incident beam are found by measuring the excitation function for Cu(p,n) and comparing with published data. The angle of incidence and its inhomogeneity are determined by beam-locating experiments, and checked by the Rutherford law for elastic scattering from heavy elements at small angles. The current is monitored by neutron counters, and measured by counting the activity in the target after bombardment. This is calibrated in a separate run against the published Cu(p,n) cross section. The background is reduced (to <5 percent at most angles) by various types of carbon shielding. Several projects based on these methods have been carried out using the ORNL 86-Inch Cyclotron, and extensions to other types of measurements are in progress.
Lens System Producing Unequal Magnification in Two Mutually Perpendicular Directions
Authors: Buchele Donald R. , Goossens Herman R.
Published: February 2005

A camera lens system, applicable to a schlieren optical system, is described, that yields an image in which the magnification perpendicular to the airflow is much greater than the magnification parallel to the airflow. Examination of boundary layer development along an airfoil surface is thereby facilitated. Optical design formulas are given and illustrated by an example in which a 24-to-1 ratio of magnifications is obtained without loss of schlieren sensitivity and without noticeable aberrations.
A Transmission Čerenkov Counter
Authors: Lindenbaum Seymour J. , Pevsner Aihud
Published: February 2005

A high efficiency transmission-type Čerenkov counter is described for use in counter telescope work. Range curves for liquids of different indices of refraction are presented.
Simple Equipment and Techniques for a Small Cryogenics Laboratory
Authors: Rasor N. S.
Published: February 2005

Simple techniques and easily constructed equipment are described for a small cryogenics laboratory utilizing a commercial helium liquefier. Emphasis is placed on simplicity and availability rather than on high accuracy and efficiency in low-temperature work. Accessories for a Collins liquefier and a commercial liquid-helium storage container are described. Techniques used for reaching and measuring intermediate temperatures are outlined, along with a description of two portable cryostats. A small mica and Pyrex platinum resistance thermometer has been developed, and its relatively simple fabrication is described.
Solid Angle Subtended by a Circular Aperture at Point and Spread Sources: Formulas and Some Tables
Authors: Jaffey Arthur H.
Published: February 2005

Some formulas for the calculation of the solid angle subtended by a circular aperture at an isotropically emitting point or spread source are presented as well as three tables of solid-angle values.
The Type 6218 Beam Deflection Tube as a Complex Pulse Generator
Authors: Enslein Kurt
Published: February 2005

The type 6218 tube provides a simple means of obtaining pulses with very fast rise time, unlimited, as heretofore, to 150 pps as in mercury-switch pulsers. It also provides a means of generating double or n pulses of variable separation at repetition rates limited only by the separation of the pulses. Circuits permitting the use of the tube, as well as wave forms produced are given.
Thermoregulator for a Liquid Helium Bath
Authors: Boyle Willard S. , Brown James B.
Published: February 2005

A simple device is described for holding the temperature of any part of a liquid helium bath constant to within ±3×10−5°K under normal conditions.