bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Charged Particles with Gas Scintillation Counters
Authors: Nobles Ralph A.
Published: February 2005

A study has been made of the pulse heights obtained from α particles in a gas scintillation counter using argon, krypton, and xenon. Measurements were made with an RCA-6342 photomultiplier viewing the scintillations directly and also with the aid of a quaterphenyl wavelength shifter. Pulse heights from xenon were about 10 times as great as those from argon and 3.6 times those from krypton. The gain in pulse height with a wavelength shifter was about a factor of 15 for each gas. The rise time of the light pulses was of the order of one mμsec or less. Pulse height was found to be a linear function of energy for protons, deuterons, and helium ions in a xenon counter with a wavelength shifter. The pulse height was independent of the type of particle producing the scintillations and depended only on the energy lost in the counter.
Fast Rise Pulse Generator with High Pulse Repetition Frequency
Authors: Dorn Clifford G.
Published: February 2005

A mercury selector switch designed for use in telemetering may be modified by using high-frequency techniques to make a fast rise time pulse generator with high pulse repetition rates. The pulse rise times are less than 0.002 μsec at repetition rates in excess of 10 kc with peak pulse power of 50 watts.
High-Temperature Vacuum Furnace for Tensile Testing
Authors: Smith E. A. , Guard R. W.
Published: February 2005

A resistance furnace using a tantalum tube heater has been constructed for tensile testing wire specimens of metals that require protection from the atmosphere, at temperatures up to 1600°C. Specimens of molybdenum and tungsten have been successfully tested in the range from 1000° to 1600°C.
Continuous Measurement of Deuterium Concentration in Hydrogen by Means of Thermal Conductivity
Authors: Silvestri M. , Adorni N.
Published: February 2005

A continuous analytical device for the measurement of deuterium concentration in hydrogen gas is described, based on differences in the thermal conductivities of the hydrogen isotopic molecules and the use of a Gow-Mac thermal conductivity unit. Calibration of the apparatus in the range 0–2.5% D/(D+H) was performed, showing that accuracy of the order of 1/10 000 can easily be achieved with well-purified gases.
Zone Reflection Camera for Studying Crystal Imperfections by the Schulz Technique
Authors: Wei C. T.
Published: February 2005

An x-ray diffraction camera for studying imperfections in single crystals by means of the Schulz technique is described. This camera provides a convenient way for aligning the crystal and for indexing the various reflections. The latter is necessary in studying the crystallography of the imperfections. Sub-boundaries and local lattice curvature with disorientation of 1 min of arc have been detected.
Automatic Measurement of Phase Retardation for Radome Analysis
Authors: Kofoid Melvin J.
Published: February 2005

A microwave interferometer has been developed for measuring the phase retardation of a wave passing through a radome wall. The instrument is used to analyze radomes which are subsequently corrected so that the phase retardations are of the desired values everywhere. High accuracy is required in the measurements. Automatic balancing of the interferometer is employed so that continuous measurements can be made.
Nonblocking Double-Line Linear Pulse Amplifier
Authors: Fairstein Edward
Published: February 2005

A linear amplifier with a 1.2-μsec clipping time and a gain of 50 000 suitable for scintillation spectrometry is described. Low-energy photoelectric peaks can be resolved under conditions in which the unwanted background has a rate in excess of 100 000 cps and has components 40 times more energetic than the desired spectrum. No shift in the energy axis is observed under these conditions.

The amplifier consists of a White cathode follower preamplifier, three feedback groups, and a White cathode follower output stage. Each of the three feedback groups contains four stages, three of which are amplifiers. Blocking is eliminated by the use of grid resistors low in value compared to the preceding stage plate load resistors. This feedback group configuration is also more linear by an order of magnitude than the conventional configuration. It is shown how RLC coupling between White cathode follower halves can conserve power supply voltage.

It is shown how a cable correctly terminated at the transmitting end rather than at the receiving end can eliminate the difficulties usually associated with the use of a long cable between preamplifier and main amplifier.
Studies with a Three-Dee Three-Phase Proton Cyclotron
Authors: Ruby Lawrence , Heusinkveld Myron , Jakobson Mark , Smith Bob H. , Wright Byron T.
Published: February 2005

As part of the program to investigate the properties of the Thomas cyclotron, a 20-in. diam proton cyclotron was constructed. In such a three-dee three-phase system it is possible to accelerate protons, deuterons, and tritons at the same setting of frequency and magnetic field but on different modes of the rf. For stable operation in the proper mode and with balanced voltages, it has been found necessary to provide both phase servos and amplifier efficiency servos. The dees could not be servoed individually until the inter-dee capacity was neutralized. Under such conditions it was possible to attain steadily 6.0 ma of protons at 1.0 Mev in the forward mode and 6.5 ma of deuterons at 0.5 Mev in the reverse mode.
Nonuniform Fields in Cycloidal-Focusing Mass Spectrometers
Authors: Robinson Charles F.
Published: February 2005

In a cycloidal-focusing mass spectrometer, nonuniformities in the magnetic and electric fields may cause either an actual deterioration of the image quality or merely a shift in the focal point. The latter effect is the more usual one and it can be compensated easily.
Cyclotron Instrumentation for Nuclear Spectroscopy at Medium Resolution in Energy
Authors: Bach D. R. , Childs W. J. , Hockney R. W. , Hough P. V. C. , Parkinson W. C.
Published: February 2005

The instrumentation for the magnetic focusing and analysis of the external beam of the Michigan cyclotron is described. It provides to a scattering chamber in an adjacent room a beam of deuterons of a few tenths microampere monoenergetic to within 15 kev at a mean energy of 7.8 Mev. A double-focusing analyzer magnet of mean radius one meter, focuses reaction products of magnetic rigidity less than or equal to that of a 20-Mev proton. At the optimum energy resolution of the system, proton groups from (d,p) reactions differing in Q by about 20 kev can be resolved. Particles can be observed over a continuum of angles from −7° to +112° relative to the incident beam. The determination of reaction energies and the measurement of relative differential cross sections are discussed.
Calculator for Some rf Problems in Accelerator Design
Authors: MacKenzie K. R.
Published: February 2005

A simple mechanical calculator has been developed for solving the transmission line equations when the characteristic impedance is a variable. The speed of computation is some two orders of magnitude faster than analytical methods. The theoretical basis is described and also the way in which it can be used. Some representative problems, which have benefited by use of the calculator, are discussed.
Nonlinear Amplifier Design for Pulse-Height Analyzers
Authors: Hutchinson G. W.
Published: February 2005

The ratio of maximum to minimum pulse sizes which can be simultaneously recorded by a kick sorter is limited by the curvature of the characteristic of its biased amplifier over a finite region of input potentials. The extent of this region can be reduced from a few volts to about 10 millivolts by including the nonlinear elements of the amplifier in its negative feedback loop. An amplifier is described which embodies this principle and also provides a discriminator and gate circuit.
Filamentary Subminiature Scalers
Authors: Harris C. C. , Bell P. R.
Published: February 2005

In order to reduce the power requirements and heat dissipation in multichannel pulse-height analyzers with parallel digital storage, we have devised and tested a low-wattage scale-of-two employing filamentary subminiature tubes. These units are designed for use in scales of 16 or 32 and exhibit great reliability and long life. The resolving time is 5 μsec with grid-catching diodes and 13 μsec unaided. For greater reliability in very long cascades and for battery operation, a Higinbotham version has been devised. Both designs promise extremely long life and may be useful wherever bistable switching circuits are used.
Light Shifter for Čerenkov Radiation
Authors: Heiberg E. , Marshall J.
Published: February 2005

Measurements are reported of the use of luminescent materials as a light shifter for Čerenkov radiation, with the object of increasing the pulse height from Čerenkov light observed by a photomultiplier tube. By this process the directional properties of the Čerenkov light are essentially lost.
Microscope for Large Nuclear Plates
Authors: Zorn G. T.
Published: February 2005

A precision microscope which may be used with all sizes of nuclear plates up to 10×16 in. has been constructed. Its simplicity of construction, and flexibility and ease of use recommend its general design.
Photometric Ionization Measurements in a Multiplate Cloud Chamber
Authors: Caldwell David O. , Pal Yash
Published: February 2005

A method has been developed for determining photometrically the ionization of multiplate cloud chamber tracks. A simple, projection type of photometer is used to measure the track opacity, from which the ionization of the track is obtained by comparison with the opacity of a track of known ionization. The ratio of the properly normalized opacities of the two tracks is related to the ratio of their ionizations by a simple power law. The technique has been employed, with geometric residual range determinations, to find particle masses. It also has been used, when the mass is known, to ascertain the residual range in the plate in which a particle stops. By determining both the ionization and the change in ionization occurring in a plate traversal, both the mass and the residual range of particles have been found. Specific applications include a determination of the range of the secondaries from Kμ2 and Kπ2 decays, and a measurement of the mass of a particle which releases more than 1.6 Bev on stopping. The latter is found to have a mass consistent with its being an antiproton.
Preparatory and Air-Driven Micromanipulators for Electrophysiology
Authors: Békésy G. v.
Published: February 2005

A little trick is described, which facilitates the carrying out of anatomical or physiological preparations that are extremely delicate to handle with free hands. It consists mainly in a support and a screwdriver acting as a lever to reduce the movements of the hands.

For very fine micromanipulations, where even touching the operating table must be avoided, an air-driven micromanipulator has been built, in which a small air-driven turbine rotates the adjusting screws of the manipulator. Movement in various directions can be performed by pressing keys which open air pressure valves. All the movements can be programmed in advance by means of prepunched holes in a paper strip of the type used in teletype systems.
High Temperature Modification of the Beckman DU Spectrophotometer
Authors: Sundheim Benson R. , Greenberg Jacob
Published: February 2005

A modification of the Beckman DU spectrophotometer is described which is capable of observing absorption spectra of liquid systems up to 650°C.
Conversion of Quantum Counting Rate to Roentgens
Authors: Kohler T. R. , Parrish William
Published: February 2005

Expressions are derived relating counting rate measured with quantum detectors to the dosage rate in roentgens. The number of quanta/cm2 per roentgen is strongly energy dependent. In the x-ray region 5 to 50 kv, however, the variation of the quantum counting efficiency with wavelength of some counters (e.g., argon Geiger counter) matches fairly closely the energy dependence factor, and hence such detectors can be used as r-meters.
Square-Wave Electromagnetic Flowmeter Design
Authors: Denison A. B. , Spencer M. P.
Published: February 2005

The square-wave principle for electromagnetic flow recording offers several theoretical advantages over the dc or ac systems, particularly for blood flow recording from intact vessels. The degree to which these advantages may be obtained in practice depends upon the extent to which the equipment meets the specific requirements of the principle. This paper considers the objectives that should be considered in design and construction of a practical equipment.
Compton Backscattered Photons in Precision Proportional Counter Spectrometry
Authors: Fink R. W. , Robinson B. L.
Published: February 2005

The importance of Compton backscattering in gas proportional spectrometry in the energy range 10 to 100 kev is pointed out. If the backscattered photons are unresolved from the main peak, a large error may be introduced under certain conditions in absolute and relative intensity measurements based on theoretical quantum efficiency (geometry×absorption); if the backscattered peak is resolved, failure to recognize its origin may result in the ``discovery'' of a new gamma ray. The effect is especially pronounced when a collimator is used to establish geometry; for example, the intensity of backscattered photons can amount to as much as half the intensity of the main peak at 46.5 kev with a ¼-in. diameter collimator.
Influence of Magnetic and Electric Field Distribution on the Operation of the Omegatron
Authors: Brubaker Wilson M. , Perkins George D.
Published: February 2005

The operation of an omegatron is discussed with polyphase electric excitation. Use is then made of this analysis to investigate the ionic trajectories in an omegatron in which the natural frequency of the ion is a function of the orbital radius. This circumstance comes about from either the influence of space charge or from the use of a magnetic field which decreases with increasing radius.

The nonuniform magnetic field and the radial electric field can enhance the resolving power. It also influences the peak shape, causing the sides to be nearly vertical.

Trapping of the ions is essential for satisfactory operation of the omegatron. Two experimentally proven means of accomplishing trapping are presented.
Stark Modulation Atomic Clock
Authors: Takahashi I. , Ogawa T. , Yamano M. , Hirai A. , Takeyama M.
Published: February 2005

An atomic clock utilizing the Stark effect has been designed and constructed. In this clock, the error caused by the reflections in the microwave circuits has been successfully reduced to within the error by random noises, and the authors are sure of its possibility of long time operation. The accuracy has been estimated to be about 5×10−9 from observation of the received frequency of the standard station JJY, and comparison with the frequency of a quartz chronometer. The various components of this clock are described in detail, and the theoretical limits of the accuracy are also discussed.
Analysis of Phase-Shift Controlled Thermoregulator Circuits
Authors: Brooks A. A.
Published: February 2005

The power sensitivity and the line voltage variation effects of a phase-shifting thermoregulator making use of a thermal element in a Wheatstone bridge and a grid-controlled thyratron are expressed in terms of the circuit parameters. The conditions for line voltage variation compensation are derived and the calculated results are found to be in good agreement with the experimental value.
Electromechanical Crystal Structure Factor Computer
Authors: Van Der Walt N. T.
Published: February 2005

An electromechanical device is described for computing the two-dimensional structure factor formulas, ∑ r=1Nfr{sincos}2πhur{sincos}2πkvr  and   ∑ r=1Nfr{sincos}2π(hur+kvr).fr, ur, vr are fractional and may be fed in to the third decimal place; h and k may vary from −20 to +20. Each term in the series is computed individually to an accuracy of approximately ½% and is automatically added to the existing sum whilst the next term is being computed. The speed of computation is generally equal to the speed with which the variables of each term are fed into the computer. The machine makes use of ``magslip'' resolvers for computation of the trigonometrical functions.
Rotating Probe Electrometer
Authors: Devins J. C. , Reynolds S. I.
Published: February 2005

A new type of scanning electrometer is described which is capable of measuring the charge on areas as small as 0.3 cm2 at a rate fast enough to show changes in charge distribution on a dielectric surface within intervals of the order of 30 msec. The minimum charge density which can be measured is about 0.6×10−9 coulomb cm−2. Resolution of charged areas of the order of one millimeter apart is possible. This provides a new tool for studying the distribution of surface charges in detail.
High Transmission Mechanical Neutron-Monochromator for Filtering of Higher Order Reflections
Authors: Holt N.
Published: February 2005

The construction of a mechanical neutron monochromator for the cold neutron region with 80% transmission is described. The apparatus is specially designed to be used in connection with a neutron crystal spectrometer for filtering out higher order reflections by placing it between the crystal and the counter. An experimental test of the machine has been performed by measuring the gold cross section and the neutron intensity as a function of the angular velocity of the rotor for a certain wavelength. The result shows that no higher order neutrons are transmitted.
Servomechanism for the Regulation of Blood Pressure
Authors: Sager Naomi , Waite John H. , Poppell J. William , Howland William S.
Published: February 2005

A blood pressure regulator for use in cases of shock, hypotensive anesthesia, and in medical research is described. The difference between measured and reference values of blood pressure is used to control the infusion rate of drugs acting on the cardiovascular system. Although the system is inherently nonlinear, it is stable when operated with restricted gain.
Periodic Sampling Logarithmic Amplifier
Authors: Nettel Stephen J.
Published: February 2005

The logarithmic response of the amplifier described in this paper is derived by extracting an output proportional to the time required for the voltage across a parallel resistance condenser combination to decay to a small fixed value. The input voltage is sampled with a 400-cy converter. Accordingly, the amplifier is restricted to a resolving time of 1/400th of a second. A logarithmic response over four decades with a deviation of less than 1% of the maximum output is secured. The immediate purpose of the amplifier is to aid in the study of the transients associated with photocells.
Conversion of an Infrared Spectrophotometer Incorporating a Memory System to Double Beam Operation
Authors: Kruse K. M. M.
Published: February 2005

The conversion of a Beckman IR2-T infrared spectrophotometer to double beam operation, using as many units of the original instrument as possible, is described. The Brown recorder incorporated in the original system is used as a ratio recorder by applying the reference signal to the slide wire input. A compensation method for signal intermodulation, previously not used in similar systems, is described and some technical difficulties are pointed out.
Gas Scintillation Counter
Authors: Sayres A. , Wu C. S.
Published: February 2005

A systematic investigation of the optimum conditions for the design and operation of a gas scintillation counter has been made. The gases studied were xenon, krypton, argon, helium, and various gas mixtures. Both a 6292 and a quartz window K1306 phototube were used with and without quaterphenyl as a wavelength shifter. Under optimum conditions an energy spread of less than 4% is obtainable for the Po210 α particles. The application of the gas scintillation counter as a fast ``slow neutron detector,'' using the reaction B10(n,α)Li7, and its usefulness as a fast fission detector have been examined and discussed.
Apparatus for Measuring Very Low Interfacial Tensions
Authors: Jennings H. Y.
Published: February 2005

A pendent drop apparatus for rapidly measuring very low interfacial tensions is described. Interfacial tensions as low as 0.001 d/cm have been measured at 25°C in a water-oil system. These measurements were made possible through the combined use of small drop-forming tips, long working distance objectives, electronic flash illumination and Polaroid Land film. Examples of measurements on water-oil systems are given. The apparatus is designed to provide interfacial tension data as a function of temperature. In addition, the method permits the measurement of interfacial tension as a function of the age of the interface.
Optical Autocorrelation Measurement of Two-Dimensional Random Patterns
Authors: Kovásznay Leslie S. G. , Arman Ali
Published: February 2005

A function of two independent variables can be regarded as an image. Using a novel optical technique, the autocorrelation coefficient of such a function is formed as another image. The working principle of the instrument is based on geometrical optics alone, however, the basic equipment was further improved by adopting electronic scanning techniques. Test plates with prescribed autocorrelation functions were made, the equipment was experimentally tested, and was found to operate to satisfaction.
Mach-Zehnder Interferometer for Diffusion Measurements in Volatile Liquid Systems
Authors: Caldwell C. S. , Hall J. R. , Babb A. L.
Published: February 2005

The constructional details and method of operation of an optical diffusiometer are described. The apparatus makes use of a Mach-Zehnder-type interferometer, which has not previously been employed for the study of diffusion in liquid systems. The apparatus has been developed for the study of liquid systems whose components are volatile organic solvents. For this purpose a diffusion cell of novel design has been constructed. The diffusiometer has been checked using the system sucrose-water at 25°C and values of the diffusion coefficient found over six determinations are within 0.2% of the reported value. With volatile liquids, the accuracy claimed is only 1%, although duplicates usually agreed to within 0.5%.
New Method for Measuring Linear Compressibility of Solids
Authors: Reitzel J. , Simon I. , Walker J. A.
Published: February 2005

An apparatus is described for measuring linear compressibility of rods and tubes under hydrostatic pressures to 4000 kg/cm2 and temperatures to 260°C. The measurements are made by means of a linear-differential transformer located on the outside of the nonmagnetic high-pressure container. The differential transformer makes it possible to determine the position of a small iron cylinder affixed to the sample. Compressibility of vitreous silica determined by this method was obtained as −ΔV/V=p(26.43–0.0049t) ×10−7+p2(21.8–0.040t)×10−12; compressibility is expressed in relative volume change, p in kg/cm2 and t in °C.
Space Charge Neutralization in the Ionizing Beam of a Mass Spectrometer
Authors: Plumlee R. H.
Published: February 2005

A mass spectrometer ion source structure and its mode of operation are described by which the resolved ion current produced from a given gas concentration in the ionizing chamber can be made one to two orders of magnitude larger than is usually obtained in conventional mass spectrometer ion sources. This structure employs an ionizing chamber whose walls are electrically insulated from each other so they can operate at separate potentials which permit positive ions to be trapped in the ionizing electron beam. The resulting partial neutralization of the electronic space-charge allows the use of a higher current density ionizing beam and also increases the effective ionizing volume from which a stable ion current can be extracted. Inherently this mode of operation produces more fragmentation species because it increases the probability of several successive electron impacts on each particle.
Cryogenic Electromagnets. I. Feasibility Study
Authors: Laquer Henry L. , Hammel Edward F.
Published: February 2005

Electromagnets have been built for continuous operation in liquid hydrogen. A steady field of 62 000 oersted, corresponding to a power dissipation of 15 kw has been obtained in freely boiling hydrogen with a coil 5 in. long, 2.5 in. internal diameter, and 7.5 in. external diameter.

Some of the mechanical, electrical, heat transfer, economical, and safety problems encountered in this work are discussed.
Twin Cavity for NH3 Masers
Authors: Bonanomi J. , Herrmann J. , De Prins J. , Kartaschoff P.
Published: February 2005

A system of two coupled cavities is described replacing the single cavity of an NH3 maser. Using this system the curve of the oscillation frequency against cavity temperature presents a plateau, thus reducing considerably the ``pulling'' effects of the cavity.
Continuous-Recording Laboratory Thermobalance
Authors: Bartlett E. S. , Williams D. N.
Published: February 2005

Instrumentation for continuous, automatic recording of weight change in laboratory tests was constructed. Sensitivity and accuracy of the instrument permitted transcription of weight change rates from 3 to 70 mgs per min. Suggestions for instrument design for measurement of oxidation rates in the order of 0.1 mg per hour are presented.
New Integrating Circuit and Electrical Analog for Transient Diffusion and Flow
Authors: Macdonald J. Ross
Published: February 2005

A circuit for the electrical simulation of transient diffusion and flow of material between two volumes is described. It allows such processes to be simulated even when forward and reverse transfer rates between the two volumes are unequal. When the reverse rate is zero, the circuit functions as a very-high-input-impedance integrator of wide dynamic range and high accuracy. The circuit will integrate the current through a given resistor, even when this resistor is time varying or nonlinear. For voltage integration, it can have a minimum input impedance approaching 109 ohms.
Sampling Oscilloscope for Statistically Varying Pulses
Authors: Sugarman Robert
Published: February 2005

A sampling oscilloscope is described with a 10 to 90% rise time of 5.6×10−10 sec. Maximum useful sweep speed is about 10−10 sec/in.; maximum useful sensitivity about 15 mv/in. These are limited solely by the peak time jitter of 2×10−11 sec, and apparent input peak noise of about 300 μv. Unlike prior sampling devices, pulses of constant or random repetition rate are displayed with equal facility. The usual time jitter associated with the display of random pulse heights is eliminated by selecting for display only those pulses that fall within a kicksorter channel. The average wave form of pulses with moderately irregular shapes is particularly easy to measure.
Deviations from One-Dimensional Heat Flow in Guarded Hot-Plate Measurements
Authors: Woodside William
Published: February 2005

A theoretical analysis is made of the error in thermal conductivity, measured by the guarded hot-plate apparatus, resulting from a temperature difference, or unbalance, between the test area and guard ring. The solution is obtained by the application of two successive Schwarz transformations, the assumptions having been verified by relaxation calculations. An expression is derived for the error heat flow in the test specimens. The agreement between calculated and measured values of the error heat flow for three different hot plates for which experimental data are available is 5% or better. It is therefore now possible to calculate the maximum tolerable unbalance to achieve any desired accuracy in thermal conductivity measured by the guarded hot plate.
Aerodynamic Heating Simulator for Transducer Development
Authors: Masters Joseph I. , Cohen Milton S.
Published: February 2005

A laboratory technique for the quantitative environmental testing and comparison of various types of subsurface transducers is described. Such transducers are currently in use to determine the transient surface temperature response to intense surface heating of a metal slab that is a good heat conductor. The simulator provides surface heating whose uniformity is estimated to be within about 3% of the heating rate over an area of 1 in.2 with flux capability exceeding 1500 w/cm2. (Surface melting of a semi-infinite slab of pure copper occurs in less than 10 sec at this rate.) Because the method of heating is electric, a shaped surface heat pulse may be produced by programing an input Variac. An important feature of the device is its symmetry which permits identical heating of two opposing surfaces simultaneously.
Seals for Pressures to 10 000 Atmospheres
Authors: Daniels W. B. , Hruschka A. A.
Published: February 2005

This note discusses the use of ``armored'' O-ring seals for the pressure range to 10 000 atmospheres. In addition, a simple high-pressure pump piston seal and a proprietary surface treatment to reduce liability of galling of steel parts are described.
Mass Spectrometer for the Study of Ion-Molecule Collision Processes
Authors: Wells G. F. , Melton C. E.
Published: February 2005

A controlled pressure mass spectrometer for the study of ion-molecule collision processes is described. A pressure ratio of 200 to 1 can be maintained between the ion chamber and the analyzer tube by means of differential pumping. Ion beams of the sample gas undergo collision reactions with molecules of the same or other gases in the analyzer tube.
Variable Resistance Bicycle Ergometer for Performance of Recumbent Exercise
Authors: Sancetta Salvatore M. , Carleton Richard J.
Published: February 2005

The construction and performance details of a simple and economical bicycle ergometer for performance of controlled recumbent exercise incident to human physiological experiments are reported. Bicycle sprockets are geared by a chain drive to the shaft of a 6-volt automotive generator, which has been transformed into an eddy current dynamometer, suitably mounted on the chassis via separate external bearings. This permits free forward rotation of the external casing and measurement of the downward thrust of a torque arm (welded to the casing) on an overhead-suspended spring balance. Absorbed power (work required to operate the pedals) is varied electrically by passing a 110 ac power source through variable voltage and stepdown transformers (output range selection 0 to 20 v) and a rectifier into the generator. At rotational speeds of 40 rpm (metronome timed) the work range may be selected from 340 to 5741 ft-lb per min, with increments as low as 42 ft-lb. The apparatus provides 95% linearity through the 360-deg cycle at rotational speeds of 30 to 60 rpm in a work range of 340 to 5100 ft-lb per min.
Plane Parallel Plate Transmission Line Stark Microwave Spectrograph
Authors: Marshall S. A. , Weber J.
Published: February 2005

A parallel plane transmission system is described for use in high Stark field microwave spectroscopy. The planes of the system are optically flat silvered glass plates and are separated by plane parallel fused quartz spacers. The instrument gives intense sharp lines out to Stark field strengths of the order of 25 statvolts/cm.
Use of Coiled Capillaries in a Convenient Laboratory Flowmeter
Authors: Powell H. N. , Browne W. G.
Published: February 2005

With coiled capillaries the basic simplicity of the Hagen-Poiseuille flow equation can be retained at flow rates which are not achievable with straight capillaries. This fact lends itself to the design of flow metering systems (for liquids or gases) which appear to be intrinsically more reliable and accurate than many other types of systems, and which require only commonly available laboratory apparatus. One such metering system for gases is briefly described.
Construction and Performance of a High-Speed Cinemicrograph
Authors: Courtney-Pratt J. S. , Huggins Charles M.
Published: February 2005

This report describes the construction and performance of a high-speed cinemicrograph capable of producing a series of 200 pictures at 100 000 frames per second. The basic principle of this ``image-dissecting'' camera consists of reproducing each scene in half-tone (i.e., breaking the picture up into an array of widely-spaced dots) and interspersing succeeding frames on the same composite plate by moving the plate one dot diameter between successive frames. After processing, the frames are ``played back'' in sequence.

The technique of image dissection is further improved by the use of a plate of small, spherical lenslets to produce the dot structure. This advance considerably increases the light-gathering power and ultimate top speed of the camera, making it possible to do high-speed cinemicrography using a commercial Vickers projection microscope for magnifications up to 2000× with various illumination techniques.

The ciné record so produced is of quite high quality; each frame conveys about the same information as a standard 16-mm ciné frame. Some examples of ``movie'' scenes are shown for visual comparison.
Small Induction Motor and Bearings for Operation in Liquid Helium
Authors: Donnelly R. J.
Published: February 2005

Small Teflon and Kel-F bearings have been developed which operate in the temperature range below 80°K. They have been used to modify a commercially available induction motor for operation directly in a bath of liquid helium.
Accurate Measurement of Gas Solubility
Authors: Cook M. W. , Hanson D. N.
Published: February 2005

An apparatus and a technique accurate and reproducible to 0.1%, have been developed for measuring the solubility of gases in liquids. The criteria necessary for measurements of this accuracy have been established and examined individually in order to provide a systematic approach to the design of gas solubility apparatus.
Electron Model Fixed Field Alternating Gradient Accelerator
Authors: Cole F. T. , Haxby R. O. , Jones L. W. , Pruett C. H. , Terwilliger K. M.
Published: February 2005

A radial sector FFAG accelerator has been constructed and successfully operated. In this 8-sector accelerator electrons are betatron accelerated from 25 to 400 kev using both continuous and pulsed injection. The number of radial betatron oscillations per revolution may be varied from 2.3 to 3 and the number of vertical oscillations per revolution from 1 to 3. Calculations of these oscillation frequencies using various approximations are described and discussed. These frequencies have been measured statically with the unaccelerated beam and dynamically using an rf perturbing voltage on the accelerated beam. Results of these calculations and experiments are in satisfactory agreement. Effects of misalignments have been measured and are in close agreement with calculations presented. A survey has been made over a large area of the betatron oscillation stability region. The effects of the many resonances observed are in good qualitative agreement with theory.
Radiocarbon Dating with Liquid CO2 as Diluent in a Scintillation Solution
Authors: Barendsen G. W.
Published: February 2005

The use of the scintillation technique for radiocarbon dating has until now been retarded by the difficulties encountered in the chemical procedure. This paper shows it to be feasible to use the carbon dioxide obtained by combustion of the sample, without any further chemical conversion, as a diluent in a scintillation solution. Up to 80% by weight and possibly more liquid carbon dioxide can be dissolved in toluene+5 g/l diphenyloxazole (PPO). However, the presence of CO2 in the scintillator interferes somewhat with the light emission in such a way that the decrease in pulse height, as compared with pure toluene+5 g/l PPO, is 50% for 20% by weight dissolved CO2. This limits the percentage of CO2 that can be used effectively to about 30%.

The counting rate due to modern carbon is 9.1 c/min, and the background is 15.5 c/min. Measurements indicate however that both these figures can be improved considerably, so as to make this technique at least comparable with the gas-counting technique.
Millimicrosecond Time-to-Pulse-Height Converter Using an rf Vernier
Authors: Chase R. L. , Higinbotham W. A.
Published: February 2005

A time-to-pulse-height converter is described which uses an rf vernier technique to facilitate the timing of an event with respect to the phase of a high-frequency clock. The event starts an oscillator whose frequency differs only slightly from that of the reference clock. The phase of the low-frequency beat note is used as an index of the phase of the clock at the time the event occurred.

The system is particularly adaptable to studying fast neutron velocity distributions when the neutron pulses are produced at high repetition rates. It uses a minimum of fast circuit elements, is useful over almost the entire period between pulses at 20 Mc and higher, and gives unambiguous results. The performance with random pulses and with neutron groups has been studied with a 100-channel pulse-height analyzer.
Vactroller—A Laboratory Vacuum Controller
Authors: Penther C. J.
Published: February 2005

Pirani gauges are used in an ac bridge circuit to sense deviation from the set point, and with the aid of a porportional leak valve, control the pressure of laboratory-scale vacuum systems over the range of 0.1 to 10 000 μ of Hg. Pressure fluctuations from the controller action are negligible and stability of ±1% has been obtained over long periods without operator attention. Set point is easily adjustable by panel control knob. Commercial components are used except for the leak valve which is of special construction.
Boron-Loaded Liquid Scintillation Neutron Detectors
Authors: Bollinger Lowell M. , Thomas George E.
Published: February 2005

The general problems involved in constructing boron-loaded liquid scintillation neutron detectors are considered. The characteristics of particular counters which have been successfully used in neutron transmission measurements by the time-of-flight method are then described. The design of these counters was guided by the results of a Monte Carlo study of neutron capture in a boron-poisoned medium. This calculation gives the probability of neutron capture as a function of neutron energy, counter thickness, and time. The calculated results are compared with experimentally determined efficiencies. The advantages and problems encountered in using the boron-loaded liquid scintillator with the Argonne fast neutron chopper are discussed.
Field Stabilizer for High-Resolution Nuclear Magnetic Resonance
Authors: Primas H. , Günthard Hs.H.
Published: February 2005

Theory of design and construction of a field stabilizer for high-resolution nuclear magnetic resonance spectrometers is described. Achievable time stability is 1:108. A voltage induced by field variations in suitably located coils is amplified by a galvanometer amplifier, integrated, and fed back to a system of coils biasing the field. The feedback ratio is 70 db from dc up to 0.2 cps. The stabilizer allows measurement of nuclear magnetic resonance signals with resolution of 108 under field conditions, independent of field fluctuations produced by temperature variations and stray fields.
Designing for Safety in Hydrogen Bubble Chambers
Authors: Hernandez H. Paul , Mark John W. , Watt Robert D.
Published: February 2005

The principal hazards of operating a liquid hydrogen bubble chamber are failure of equipment (due to overpressure) and uncontrolled escape of hydrogen gas, which may cause an explosion. If safety considerations are incorporated in planning from the job beginning, components can be designed to reduce or eliminate the probability of accidents arising from the known hazards.

The degree of safety, the hydrogen safety-vent system, and the hazards, and operation of the liquid hydrogen bubble chambers at UCRL are discussed.
Bubble Chamber Pressure Gauge
Authors: Linlor William I. , Kerns Quentin A. , Mark John W.
Published: February 2005

A description is given of the mechanical gauge and electrical circuit employed for measuring millisecond pressure pulses in a liquid hydrogen bubble chamber, in a pulsed magnetic field region.

The pressure pulse produces a deflection of a diaphragm that acts as one electrode of a capacitor. The change in capacitance is measured in an electrical circuit by comparison with a reference capacitor.

A common source feeds two cables, one of which is terminated by the pressure-measuring capacitor (``transducer''), the other by the adjustable comparison unit. Pulses from the common source are reflected from the two terminations, and their difference is amplified and displayed. The circuit employed is such that the distributed capacitance of the cables does not affect the sensitivity of the system. Hence, the interconnecting cables are not limited in length up to several thousand feet.

The frequency-response limit is about 10 kc for units currently used, because of the diaphragm characteristics. Steady-pressure calibration can be employed in order to determine the pressure and output relation.
Measurement of Neutron Spectra by Use of Nuclear Emulsions Loaded with Li6 Glass Specks
Authors: Roberts J. H. , Kinney F. E.
Published: February 2005

Type E1 Ilford emulsions loaded with specks of Li6 glass were studied for the measurement of neutron spectra from ∼50 to 1000 kev. The method is independent of the neutron directions. Resolutions of about 200 kev were obtained. Calibrations were made by exposure to monoergic neutrons at several energies, and the method was tested by neutron spectra determined independently from fission and ``long counter'' data. The theory of the reduction of track data to neutron spectra is given. The results look promising for application to the measurement of neutron spectra in fast critical assemblies and for similar problems.
Low-Field Nuclear Magnetic Resonance Spectrometer
Authors: Mitchell R. W. , Eisner M.
Published: February 2005

A nuclear magnetic resonance spectrometer has been constructed and its performance at 12 and 43 gauss is discussed. The magnetic field is obtained with an end corrected solenoid powered by batteries. The best resolution obtained is 10 microgauss at 12 gauss and 20 microgauss at 43 gauss over a 30 cm3 sample. A twin-T bridge and a synchronous detector are employed for the nuclear resonance detection. Some of the measurements for which this instrument is suited are described and the results of relaxation time measurements for ethanol-water mixtures are presented.
Dipmeter Curve Comparator, an Optical Aid to the Interpretation of Dipmeter Data
Authors: Ferre Maurice , Kinnaird Richard
Published: February 2005

An optical instrument has been designed to eliminate the printing and shifting of dipmeter logs for dip calculations. The instrument comprises sliding and rotating mirrors and provides two differently colored images. Depth shift between curves thus can be determined easily and accurately.
Fade-Canceling Zero Beat Indicator for Reception of Standard Radio-Frequencies
Authors: Blume Richard J.
Published: February 2005

A simple circuit is described which enables a local secondary frequency standard to be set quickly to a definite zero beat with a received short-wave standard frequency signal, without the usual uncertainty due to amplitude fading of the short-wave signal. In principle, two identical receivers, both fed by the same antenna, are used. One receiver picks up WWV, for example, and a weak signal from the local standard. The other picks up WWV either alone or together with a second weak signal from the local standard which is 180° out of phase with the first. The outputs of the detectors of the two receivers are subtracted, leaving only the beat note, which is recorded on a strip chart. In practice, one unmodified AM receiver is used on a time-sharing basis by means of a chopper. The band width of the device may be made much less than one cycle per second, and therefore, it is particularly useful when the WWV signal is reasonably stable in phase but far too weak for an audible zero beat to be achieved. Alternatively, the device may be regarded as a simple means of observing fast Doppler shifts of a received standard frequency signal. A schematic diagram and sample recorder charts are included.
Scintillation Camera
Authors: Anger Hal O.
Published: February 2005

A new and more sensitive gamma-ray camera for visualizing sources of radioactivity is described. It consists of a lead shield with a pinhole aperture, a scintillating crystal within the shield viewed by a bank of seven photomultiplier tubes, a signal matrix circuit, a pulse-height selector, and a cathode-ray oscilloscope. Scintillations that fall in a certain range of brightness, such as the photopeak scintillations from a gamma-ray-emitting isotope, are reproduced as point flashes of light on the cathode-ray tube screen in approximately the same relative positions as the original scintillations in the crystal. A time exposure of the screen is taken with an oscilloscope camera, during which time a gamma-ray image of the subject is formed from the flashes that occur. One of many medical and industrial uses is described, namely the visualization of the thyroid gland with I131.
Film Thickness Determination from Substrate X-Ray Reflections
Authors: Keating D. T. , Kammerer O. F.
Published: February 2005

A method is given for the determination of the thickness of films using x-rays diffracted from the substrate. The x-rays pass through the film and are diffracted by the substrate back to the counter, the intensity being reduced by absorption due to the double transmission through the film. No assumptions need be made about the substrate reflection. Unknown conditions of the substrate are eliminated by measurement of the intensity of two orders of a reflection, or measurement of the intensity of a reflection using two different incident radiations. The method is suitable for all types of film, and is particularly useful in measurements of films containing elements of the substrate for which cases x-ray fluorescence techniques are of little value. The procedure is illustrated with a measurement of the thickness of zirconium nitride on a zirconium substrate.
Recording Microwave Hygrometer
Authors: Magee J. B. , Crain C. M.
Published: February 2005

This paper describes a rapid response microwave hygrometer for continuously recording the water vapor pressure of atmospheric air over a wide ambient range. The principle employed involves the measurement by means of a cavity resonator of the contribution of water vapor to the refractive index of atmospheric air. The device described also has potential application to the continuous measurement of the degree of contamination of one gas (or of gas mixtures) by another gas (or gases).
Method of Canceling Energy Fluctuations of a Van de Graaff Ion Beam
Authors: Parks P. B. , Newson H. W. , Williamson R. M.
Published: February 2005

A varying correction voltage is applied to the target which cancels beam energy fluctuations. This correction voltage is a known, constant multiple of a small, variable voltage which must be applied to the outer plate of an electrostatic analyzer to keep the beam centered at the analyzer image slits. The beam current at the analyzer image slits provides the signal which, when amplified by an electronic device called the Homogenizer, drives both the outer analyzer plate and the target. The energy spread is reduced to 250±120 ev and is probably due only to the ion source. If the HH+ beam is put through the analyzer, the unlimited H+ beam also has an energy spread of 250 ev. The 1.76-Mev C13(p,γ) and 0.992-Mev Al27(p,γ) resonances were used to test performance. Our data are consistent with Γ(C13) = 75 ev and Γ(Al27) = 100 ev. The upper limit for the C13 width is 150 ev.