bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic Recorder for Nuclear Pulses
Authors: Cavanagh P. E. , Boyce D. A.
Published: February 2005

A simple reliable process is described for recording the amplitudes of individual pulses on magnetic tape. This enables the pulse analysis to be performed after the experiment, and under optimum conditions. Low counting rates may be recorded with the tape moving slowly, and then speeded up on playback, so that, for example, a twenty-four hour run may occupy only seven minutes analyzer time. The recording process is strictly linear over a range of signal/rms noise of up to 300/1. A maximum rate of 4000 pps may be recorded. The resolution varies with pulse amplitude, but, over the upper two-thirds of the linear range the relative spread assumes a very nearly constant value of about 3%.

A further development is described in which gated time coincident pulses are recorded simultaneously on twin tracks of the same tape. In data gathering power this system is better than an array of thirty conventional thirty channel pulse analyzers. It may also be applied to the simultaneous recording for separate analysis of the outputs of up to about ten independent detectors.
Constant Stress Creep Apparatus
Authors: Boettner Raymond C. , Robertson W. D.
Published: February 2005

A simple creep apparatus for approximating a constant stress in tensile specimens of large cross sections, where large applied loads are required, is described. The apparatus consists of a lever with a large built-in mechanical advantage, together with means for removal of incremental weights from the applied load.
Slide Rule for Radiographic Analysis
Authors: Lundberg Bruno , Henke Burton L.
Published: February 2005

A simple slide rule has been developed which will permit a rapid and accurate determination of radiographic sample transmission, of absorption index, μm, and of the photographic film density corresponding to the direct x-ray beam by means of a single setting of the sliding scale.
Fast Detector of Heavy Particles
Authors: Stein W. E. , Leachman R. B.
Published: February 2005

A fast, high-efficiency detector of heavy particles that results in negligible changes in the velocity and direction of the detected particles has been built. The detector consists of an electron accelerator and a scintillator that responds to delta particles emitted by the passage of each particle through a thin foil. For fission fragments, time resolutions of 3×10−9 sec, with efficiencies greater than 95%, have been obtained. The fragment velocity loss in traversing the thinnest foils used was less than 1%.
Thermal Contact and Insulation below 1°K
Authors: Wheatley J. C. , Griffing D. F. , Estle T. L.
Published: February 2005

Experiments on rapid thermal contact with a single crystal of ferric ammonium alum are discussed and the heat flow rates fitted to the empirical formula Q̇=½aA(THn−TCn). Thermal links of crystalline quartz and 99.999% copper and bonding agents of GE 7031-Toluene and Apiezon J oil were used and gave substantially the same results with a≅104 erg/(sec cm2 K°n) and n≅2.5. The heat flow rates have also been measured for a strand of No. 40 copper wire 55 mm long, and for a bundle of ten glass tubes, each 50 mm long, 2.0 mm diameter, and 0.19-mm wall thickness. These data were fitted to the formula Q̇=BTHn. For the copper and for a single glass tube one finds, respectively, B=28 and 0.95 erg/(sec K°n) and n=1.7 and 2.6. Solid and gaseous conduction, radiation, and vibration, the four main problems in thermal insulation below 1°K, have also been studied. Guiding principles have been established for the design of sample holders yielding reproducibly low heat leaks. A sample holder is discussed in which an ultimate heat leak of 1.6 erg/min was obtained. The techniques developed have been applied to the design and construction of a simple two-stage adiabatic demagnetization apparatus for use with single crystals.
Intermediate-Image Pair Spectrometer
Authors: Alburger David E.
Published: February 2005

An iron-free intermediate-image beta-ray spectrometer has been constructed having a momentum spread (full width at half-maximum) for a point source of conversion electrons continuously variable between limits of 0.5% and 4% with corresponding transmissions of 1% and 8% of 4π, respectively. The line half-width contribution due to source size is 0.3% per mm of diameter. At a power dissipation of 100 kw the spectrometer focuses electrons of 9-Mev energy allowing positron-electron pair lines corresponding to transitions of up to 19 Mev to be measured using a double-crystal statistical-separation detector together with a fast coincidence circuit. In tests with the 6-Mev nuclear transition in O16 using a Van de Graaff beam spot 1 mm in diameter the momentum half-width of the pair line can be varied from 0.56% to 2.5% with corresponding absolute transmissions of 0.07 to 6.3 pair counts per 105 source transitions, respectively. The energy of this transition has been determined as 6.065±0.009 Mev. Electron-gamma and electron-electron coincidence measurements on radioactive sources may be made with the spectrometer in conjunction with crystal detectors placed near the source.
Peak Pulse Brightness Photometer
Authors: Wijnberg Louis
Published: February 2005

A photometer is described for measuring the peak brightness of light flashes 0.3 μsec in duration and 10−3 in.2 in cross-sectional area. A telescope and beamsplitter arrangement permits convenient and rapid aiming. The light flashes are sensed by an RCA 931-A multiplier phototube, and the resultant electrical signals are transmitted to a pulse lengthener with appropriate 0.1-μsec rise time circuitry. A single transient will fully deflect the output meter for a period of five seconds.
Negative Hydrogen Ion Source
Authors: Phillips J. A. , Tuck J. L.
Published: February 2005

An rf ion source of conventional type is shown to yield a current of 2.2 μa of negative hydrogen ions. This is accomplished by charge exchange of the positive ions emerging from the plasma with the neutral gas in the probe channel. The negative ion beam is well focused, and the performance of the source is 0.22 μa/cc at NTP/hour. The differential equations for the above charge exchange process are set down and solved, and found to be consistent with the observations to within an order of magnitude using published cross sections. The theory also predicts a sizable neutral beam (∼60 μa) of energy 2–3 kev. According to the equations and the published positive ion performance of these sources, many times larger negative hydrogen ion yields should be obtainable if required.
Pulse Counting Photometer for Microspectroscopy
Authors: Thornburg Wayne
Published: February 2005

A photometer for recording the absorption spectra of microscopic samples in the visible and ultraviolet regions is described. Light intensities are measured by counting the pulse output of a cooled photomultiplier tube. Double-beam operation is achieved through the use of a rotary shutter and a gating circuit which sorts the beams into separate scaling channels. Optimum signal-to-noise levels are obtained by pulse-height discrimination. In typical operation the noise level is approximately 20 photoelectrons per minute, the signal level at 100% transmission is approximately 20 000 photoelectrons per minute, and approximately 50 absorption points are recorded per hour at an accuracy of ±1%. The system minimizes the errors which result from fluctuations in light source intensity, amplifier drift, and variations in photomultiplier plate voltage so that accuracies of ±0.1% can be achieved with the photometer (but not with the microspectrometer). With appropriate correction for noise and resolving time the system can be operated over four decades of light intensity. Application of this type of photometer to other spectrographic problems is suggested and representative data are presented.
High-Energy Neutron Detectors Employing Liquid Scintillators
Authors: Christie E. R. , Feld B. T. , Odian A. C. , Stein P. C. , Wattenberg A.
Published: February 2005

Two liquid scintillation type neutron detectors with efficiencies of the order of 5% for counting 130-Mev neutrons have been studied. A fairly monoenergetic source of neutrons was obtained from the photodisintegration of deuterons. Estimates were made of the efficiencies of the counters as a function of bias. Experiments indicate: (1) an appreciable effect of the products of neutron reactions with carbon; (2) the efficiency can be more accurately predicted for a small counter although the behavior of large counters can be qualitatively predicted; (3) the attenuation due to a lead shield in the beam depends upon the neutron energy, the bias, and the geometry; (4) lead shielding on the sides is relatively unimportant if kept thin.
Tritium Gas Target for Neutron Production
Authors: Johnson C. H. , Banta H. E.
Published: February 2005

This paper reports a self-contained tritium gas target including beam collimator, target cell, and gas reservoir which has been used for the production of neutrons from the T(d,n)He4 and T(p,n)He3 reactions. Beam collimators are 0.14-in. tantalum apertures aligned in precision 1-in. tubing to assure accurate beam measurement. The gas cell is 516 in. diam and may be any length less than 3 in. The target window is a 0.00005-in. nickel foil soldered on a ¼-in. i.d. re-entrant tube. Tritium is supplied from a uranium-tritide oven; hydrogen-tritium exchange is minimized by the use of nonhydrogenous materials. A discussion is given of handling of tritium. The target will tolerate a 1 μamp beam of 2-Mev deuterons for several days without foil damage.
Simple Sensitive Electrical Pressure Gauge
Authors: Sancier Kenneth M. , Richeson William
Published: February 2005

A simple, sensitive, electrical pressure measurement device has been constructed which is capable of measuring and recording absolute or differential pressures of corrosive materials of isolated systems. A linear variable differential transformer attached to a sylphon bellows indicates differential pressure across the bellows or serves as a null indicator when an unknown pressure on one side of the bellows is balanced with a gas of measurable pressure on the other side. In order to prevent inelastic deformation, the motion of the of the bellows is limited to 60 mm Hg, although larger pressure differentials can be measured. The sensitivity is independent of temperature and pressure and the device can be compensated for temperature. Absolute pressures and small differential pressures can be measured to ±0.02 mm Hg with an input signal of 2 kc, and to ±0.005 mm Hg with an input signal of 10 kc. A vacuum tube voltmeter with a full scale of 1 millivolt is used as the output indicator.
Low-Frequency Power Spectrum Analyzer
Authors: Firle Tomas E.
Published: February 2005

A system used to obtain power spectra for the frequency range from 0.00006 to 0.02 cps is described. The instruments shifts the low frequencies into the audio range where they are analyzed with an electronic audio-frequency wave analyzer. The frequency shift is achieved by recording the low-frequency phenomenon on photographic film in the form of a variable-area recording. The film is played back at a greatly increased rate, modulating a phototube current which is fed into an analyzer. Speed-up ratios, i.e., multiplications in frequency, of more than 500 000 times have been attained.
Scintillation Spectrometry Using Long Light Guides
Authors: Tove P. A.
Published: February 2005

The attenuation of different types of light guides used with scintillation counters has been measured. The detrimental effect of the guides in scintillation spectrometry has been studied.
Fast-Closing Vacuum Valve
Authors: Knudsen Arthur W.
Published: February 2005

A swinging-gate type valve with associated triggering mechanism is employed as a protective device for quickly stopping a sudden accidental inrush of air to a vacuum system. The electrical triggering mechanism uses no vacuum tubes. For a large inrush of air, the valve will close in less than 0.01 sec.
High-Speed Scaling with a Decade-Counter Tube
Authors: Porat D. I.
Published: February 2005

A E1T decade-counter tube is used in conjunction with an energy-storage counting circuit. The stray capacitance at the anode of the decade tube serves as the energy storage element, while the stabilizing characteristic of the tube itself makes the circuit completely aperiodic. A secondary-emission tube, type EFP60, produces a 0.15-μsec high current pulse for resetting the decade counter to zero at each tenth input pulse. Double-pulse resolution of <1 μsec and a continuous rate of above 106 pps have been achieved.
Constant Current Source for Direct Current Arcs
Authors: Van Der Walt N. T.
Published: February 2005

A method is described by means of which the direct current of a spectrochemical arc is kept constant at any value between ½ and 20½ amp in steps of ½ amp, independent of arc gap or the material to be excited. The principle involved is phase control on the grids of thyratrons and the design features which affect this particular application are discussed.
Rapid-Closing Electronically-Operated Shutter
Authors: Edgerton Harold E. , Strabala Francis I.
Published: February 2005

A shutter that closes quickly for capping drum cameras is described. A density of 3 is obtained in about 30 μsec by the sudden evaporation of a network grid of small lead wires. Energy for the evaporation and control of the operation instant are accomplished by a charged capacitor and a series hydrogen thryatron respectively.
Hydrogen Bubble Chamber Used for Low-Energy Meson Scattering
Authors: Nagle D. E. , Hildebrand R. H. , Plano R. J.
Published: February 2005

A 2.5×2.5×10-cm hydrogen bubble chamber has been developed for experiments on the scattering of particles from the 450 Mev synchrocyclotron. Seventy-five thousand pictures have been taken at the rate of one every two seconds and are being scanned at the rate of two thousand per day. The average track length per picture is about one gram per square centimeter. The characteristics of the bubble chamber are described and examples of the pictures are shown.
Photoelectric Angular Error Sensors
Authors: Nidey R. A. , Stacey D. S.
Published: February 2005

A technique is described for the accurate measurement of angular errors using photoelectric detectors. Utilizing two types of rugged, compact cartridges, a wide range of characteristic curves may be synthesized. Examples of various systems are shown, including one for a high accuracy servo. The latter has a coverage of 360 degrees, a null accuracy of one minute, and is in current use in Aerobee Rockets.
Analog Computer for the Differential Equation y″+f(x)y+g(x)=0
Authors: Bodenstedt Erwin
Published: February 2005

A high precision electromechanical analog computer is described. The mechanical system is a torsion pendulum. Programmed torques provide an equation of motion which is identical to the equation: y″+f(x)y+g(x)=0. The solutions are obtained by recording the motion by means of a recording camera. The analog computer is used to study the betatron oscillations and the effects of resonances for the strong-focusing Cornell synchrotron.
Development of a Vibrating-Coil Magnetometer
Authors: Smith D. O.
Published: February 2005

The vibrating-coil magnetometer measures the magnetization of a small sample of magnetic material placed in an external magnetizing field by converting the dipole field of the sample into an ac electrical signal. To allow space for temperature- or pressure-generating apparatus around the sample, the measurement is made at distances up to 2 cm from the sample. The measurement is continuous and can be recorded on a chart as a function of time, temperature, crystallographic orientation, or magnetizing field. The present stable sensitivity is such as to provide one percent accuracy for a dipole moment of 8.56×10−4 amp-m2 (the saturation moment at room temperature of a nickel sphere 1.5 mm in diameter).
Magnetically Operated Vacuum Valve
Authors: Fisher P.
Published: February 2005

A magnetic vacuum valve is described which isolates a vacuum system from its mechanical pump should a power failure occur. Also, during the isolation process, air is let into the backing pump. The valve is characterized by low cost, low power consumption, simplicity, and reliability of operation.
Simplified Radio-Frequency Ion Source
Authors: Allison S. K. , Norbeck E.
Published: February 2005

The quartz or glass sheathed cylindrical cathode probe of the conventional rf ion source has been eliminated. The conventional glass pad electron beam ``back stop'' has been replaced by nonfracturing porcelain. Commerical Pyrex pipe has been used in the construction of the glass thimble in which the plasma is formed, and the thimble sealed to the base with O-ring pressure seals. The anode probe is removable for ease in cleaning. The source produces 300 μa of H+; it also produces 200 μa of He+, and at low operating gas pressures, usable amounts of He++, as large as a few tenths of a percent of the He+ output.
Simple, Rapid Sputtering Apparatus
Authors: Belser Richard B. , Hicklin Walter H.
Published: February 2005

A simple sputtering apparatus that consistently deposits opaque films of nickel and the noble metals in 3 to 10 min has been made. The chamber is constructed from a standard Pyrex pipe reducer. By use of a large-diameter aluminum rod as the cathode support and a hemispherical aluminum shell as a shield for the pump orifice and base plate, the glow discharge has been confined primarily to the volume between the cathode and the work stand. The efficiency of the coating unit has thereby been increased. Films of nickel, iridium, ruthenium, and osmium formed on glass or quartz substrates were very adherent and were not readily scratched with a steel scribe.
Simultaneous Measurements of Density, Viscosity, and Electric Conductivity of Melts
Authors: Mackenzie J. D.
Published: February 2005

An apparatus is described for the simultaneous measurements of density, viscosity, and electric conductivity of ionic liquids at high temperatures. Density is simply measured by the suspension of a platinum bob in the melt contained in a platinum crucible situated inside a vertical tube furnace. The bob is suspended by a platinum wire attached to one arm of an analytical balance. Upward or downward motion of the bob in the melt is produced by changing the weights on one pan of the balance. The velocity of the bob, directly dependent on the viscosity of the melt, is calibrated against a standard liquid from 10 to 10 000 poise. By using the suspension and the crucible as the two electrodes, the apparatus becomes a conductance cell. The corrections in density measurements due to surface tension are eliminated by the use of two bobs of different dimensions but similar suspension wires. This furnishes not only duplicate viscosity results but also two cell-constants for electric conductance. Vacuum fusion is possible in the same apparatus.
Tritium Survey Instruments
Authors: Driver G. E.
Published: February 2005

Portable counters for the detection of surface and air tritium contamination are described. The surface monitor uses a sponge rubber seal to the surface with an argon-methane counting mixture being admitted during measurements. The air monitor mixes methane with the air before counting, and is capable of detecting a tritium concentration of 10−5 mc/cc of air.
Convection Type Manometer
Authors: Johnson J. B.
Published: February 2005

A manometer is described which depends on heat convection rather than molecular heat conduction. Its range may be from a few mm of Hg to atmospheric pressure or more. Its performance for various conditions is explored, including its possible use as an inclinometer.
High Sensitivity Ballistic Fluxmeter
Authors: Pohm A. V. , Rubens Sidney M.
Published: February 2005

The sensitivity of a ballistic galvanometer, used as a fluxmeter, can be considerably increased when it is employed for measuring flux changes which occur in a time which is much less than the damping time, in the case of a highly damped galvanometer, or the period of oscillation for a slightly damped one. This is accomplished by mechanically opening a switch in the galvanometer test coil circuit a short time after the flux change is completed thereby leaving the galvanometer either critically or lightly damped as desired. By use of this method gain in flux sensitivity of 56 has been obtained with a critically damped Leeds and Northrup Type 2290 galvanometer. With the critical damping resistance removed, the gain is 152. Such a ballistic fluxmeter is well suited for measuring the ferromagnetic properties of very small toroidal cores frequently employed in computers, etc.
Pressure Regulator for a Low-Pressure Continuous-Flow Ionization Chamber
Authors: Lowry Ralph A. , Osher John E. , Miller Glenn H.
Published: February 2005

A description is given of an automatic pressure-regulating device for a continuous-flow ionization chamber operated in the pressure range of 1 to 10 mm Hg. The pressure monitor consisted of an oil manometer, a light source, and two phototubes arranged whereby any small change in pressure gave rise to a corresponding electrical signal. This signal was used to control the power to a thermal gas flow valve. The regulator was capable of maintaining the pressure constant to within 0.03 mm Hg for a period of at least 24 hr.
Automatic Respiratory Valve
Authors: Clark James , Reif Arnold E. , Van Ness Bradford
Published: February 2005

An automatic, electronically controlled respiratory cycling valve is described. This valve was designed for use in aerosol inhalation experiments with humans or dogs and is characterized by a low dead space (27 cc) and by wide channels for air flow (minimum dimension 1.3 cm). The valve is automatically operated by respiratory pressure changes in the order of 3 mm water.
Improved Freeze-Drying and Embedding Apparatus for Frozen Tissues
Authors: Emmart E. W. , Crisp L. R.
Published: February 2005

An improved freeze-drying and embedding apparatus has been constructed in which the design of the component parts make possible the drying of tissue under vacuum at any selected temperature between −78° and −20°C. The efficiency of operation of the equipment, with the minimum attention of the operator, is largely dependent not only upon the construction of its component parts, but upon the introduction of a solenoid automatically controlled value for the flow of water to the diffusion pump; the design of drying chamber; the Teflon coupling and offset construction of the shaft of the paraffin cup; and, the introduction of gauges which afford the direct reading of temperature and vacuum. In addition, the efficient and readily accessible set of switches, dials, and stopcocks are so arranged that gauges may be read and manipulations made from one position.
Electrostatic Particle Size Analyzer
Authors: Yoshikawa Herbert H. , Swartz George A. , MacWaters John T. , Fite Wade L.
Published: February 2005

This paper comprises the theoretical analysis and physical description of an Electrostatic Particle Size Analyzer (EPSA) for determining the particle size distribution of aerosols in the 1- to 20-micron size range. Included are photographs and histograms illustrating the size separation attained and also a histogram of the particle size distribution in the general aerosol as determined by use of the instrument.
Wide Amplitude String Galvanometer for Direct Recording
Authors: Browder Lewis B.
Published: February 2005

By employing an Einthoven or string galvanometer rather than the usual D'Arsonval galvanometer in a direct-writing oscillograph a considerable reduction in inertia of the moving element is obtained. The use of compliant end supports makes possible very large deflections so that a 10-cm long string having a resonant frequency of 230 cps can be made to move through an amplitude of 2.5 cm. The nonlinearity associated with the large amplitude can be corrected by shaping of the magnetic field, and electromagnetic damping of the order of critical or less is obtainable.
Micromanometer of High Sensitivity
Authors: Lynn Scott , Corcoran W. H. , Sage B. H.
Published: February 2005

A sensitive micromanometer based on the observation of the movement of a bubble of air in a precisionbore, horizontal capillary tube was constructed. The sensitivity was varied by connecting different-sized chambers which had nominal diameters of 1, 2, and 3 in. The sensitivity could be varied between 2×10−5 in. and 2×10−6 in. of manometer fluid.
Transit-Time Accelerometer
Authors: Jones L. M.
Published: February 2005

An omnidirectional transit-time accelerometer, developed for measuring the drag acceleration of spheres dropped from rockets, is described. The ambient density and temperature of air may be calculated from the drag acceleration. In the device, a bobbin is periodically caged and released within a cavity. The time for the bobbin to traverse the distance to the cavity, which distance is the same in any direction, is telemetered and measured. The accelerometer range is about 5×10−3 to 5 g. Systematic errors and standard deviations over the range are about 1%. The accelerometer was used successfully in a rocket flight in which the drag acceleration of a 7-in. diam sphere was measured.
Method for Eliminating Omegatron Radial Field Errors or for Direct Measurement of Mass Ratios
Authors: Woodford Hugh J. , Gardner John H.
Published: February 2005

An omegatron having two pairs of ion-accelerating plates instead of one and using resonance absorption detection has been used successfully to obtain simultaneous cyclotron resonances of two different ion species in the same field. When used in conjunction with a nuclear resonance probe, the method effectively eliminates errors due to perturbing radial electric fields in the omegatron; alternatively, if radial electric fields are considered negligible, the method permits the direct measurement of mass ratios.
Balloon-Borne System for Tracking the Sun
Authors: Edwards Howard D. , Goddard A. , Juza M. , Maher T. , Speck F.
Published: February 2005

A balloon-borne system for tracking the sun both in elevation and azimuth is described. The system weighs approximately 125 lb and is capable of ``pointing'' as much as 20 lb of payload at a predetermined position in the sky. Power requirements are 20 w. An accuracy in pointing of ±15 min of arc has been achieved. At some sacrifice in simplicity, this accuracy could perhaps be improved to ±5 min. Results of two flights, each attaining an altitude in excess of 100 000 ft, are given.
Aural Electrocardiograms
Authors: Gemant Andrew , Burch D. C. , Miller E. B.
Published: February 2005

In heart surgery the need arises for electrocardiograms that would not require visual attention. This aim has been achieved by converting the voltage wave pattern into a sound pattern of varying pitch; the latter is an exact reproduction of the voltage wave. The apparatus used for the conversion is described. Its performance on humans as subjects was found satisfactory.
Direct Recording Instrument for the Study of Clotting Phenomena
Authors: Gilson Warren E. , Morrison Peter R.
Published: February 2005

The instrument described provides a direct recording optical method of studying clotting phenomena without mechanical disturbance to the clotting system, by ``ink-writer'' recording of the response of a photo-multiplier cell to the light scattered by the system.
Device for Applying Compression to Small Crystals
Authors: Rapperport Eugene J.
Published: February 2005

The design of an apparatus for applying uniaxial compression to specimens with cross sections up to ¼ inch square is described. One feature of the apparatus is the construction of the force transmitting linkage. This linkage was designed to minimize the transmission of shear forces, and thus to avoid bending moments on the samples. The apparatus enables the compressive forces acting on the samples to be determined to within 0.1%.
``Black Ball'': A Device for Measuring Atmospheric Infrared Radiation
Authors: Gergen John L.
Published: February 2005

The problem of the atmospheric infrared heat balance has been solved graphically and analytically, but almost no experimental evidence exists to verify the calculations. The ``Black Ball'' is a device which can be flown on an ordinary radiosonde and indicates a temperature which is related to the total incident infrared flux at any point. The actually observed temperatures must be corrected for convection effects and thermal time constants. Construction and correction data are presented in this paper.
Recoil Type Neutron Spectrometer for 0.05 to 1 Mev
Authors: Perlow Gilbert J.
Published: February 2005

A neutron energy spectrometer is described, suitable for the region 50 kev to 1 Mev. Hydrogen recoils from CH4 in a proportional counter are collimated and enter a second counter. The sum of the pulse heights is analyzed whenever a coincidence occurs. A third counter in anticoincidence discriminates against cases in which all the energy is not lost in the first two. With the collimation used the energy spread is ∼10% and the efficiency an approximately linear function of energy, being 10−5 at 180 kev.
Machine for the Production of Microelectrodes
Authors: Winsbury G. J.
Published: February 2005

A description is given of a machine designed to produce microelectrodes from a standard 3-mm Pyrex glass tube. The glass tube is heated by a platinum coil and drawn into microelectrodes by a vertical two-stage pull. The first pull is by gravity and the second by an electromagnet. The operation is entirely automatic. After the machine is switched on adjustable microswitches control the sequence of operation and finally switch the machine off when the microelectrodes are drawn. Two identical microelectrodes are produced per minute. The microelectrode tip diameters may be varied from 0.5 to 10 μ. The taper towards the tip may also be varied within wide limits to suit different experiments.

Advantages of the machine over earlier microelectrode pullers are discussed together with a description of a rapid method of filling microelectrodes with conducting solutions.
Helium-Cooled Liquid Hydrogen-Deuterium Target
Authors: Janes G. S. , Hyman L. G. , Strumski C. J.
Published: February 2005

A thin-walled liquid hydrogen-deuterium target has been developed which makes use of the boil-off vapors from liquid helium as a coolant. Approximately three liters of liquid helium are required to condense the hydrogen and 0.13 liter per hour thereafter.
Gas-Flow Proportional Counter for Soft X-Ray Detection
Authors: Hendee C. F. , Fine S. , Brown W. B.
Published: February 2005

One of the major problems of analysis in the soft x-ray region is the limitation due to low transmission of the window materials of sealed-off x-ray detectors. This paper describes the properties and use of a gas-flow proportional counter system for the x-ray analysis of elements in the third period of the periodic table, with special reference to aluminum and silicon. The use of gases flowing continuously through the counter at atmospheric pressure in conjunction with helium also at atmospheric pressure in the optical path permits the use of ultra-thin nonvacuum-tight windows with high transmission in this region. Comparative data, obtained on a Norelco fluorescence spectrometer, show a tenfold increase in counting efficiency for AlKα over detectors previously available for this application.
Generator of Linearly Varying Voltage
Authors: Levinson John
Published: February 2005

An all-electronic generator is described which provides a voltage which varies linearly with time between adjustable positive and negative limits. Such a generator lends itself well to the automatic recording of current-dependent phenomena. Linear variation is obtained on both the rising and falling half-cycles, so that complete reversal of slow processes may be assured. The maximum current provided in either direction is 3 amps. The limit is determined by the number of output tubes connected in parallel. Cycling periods up to 1 min in length are provided.
Ultrasonic Intensity Meter
Authors: Wiederhielm Curt A.
Published: February 2005

A calorimetric method for measuring ultrasonic intensities is described. By the use of agar, the formation of standing waves and the disturbance of the ultrasonic field being measured is avoided. Intensities in a small area can be measured, making it possible to get valid readings of peak intensities in a large nonuniform ultrasonic field.
``Glo-Ball'' Development
Authors: Steinhaus James F.
Published: February 2005

The term ``glo-ball'' is used to designate a small, thin-walled, partially evacuated glass sphere containing helium, used for investigating electric field distributions in rf resonant cavities. Ionization, or firing, of the gas in the glo-ball indicates a given potential gradient across it; in field investigations a monitoring loop is used to record the voltage required in the cavity to produce this ionization. Glo-balls were developed specifically for their application to linear accelerators.

Experiments were conducted to provide a method of making glo-balls, under controlled conditions with known constituents, that would have a stable and relatively low firing gradient.

Factors associated with the making of a glo-ball were determined, and a spectroscopic analysis identified the gas components. It is now possible to make a ball that fires at a minimum voltage gradient with excellent stability. Other characteristics of the glo-ball pertinent to its use as a field-measuring device were investigated.
Nonlinear Response of NaI(Tl) to Photons
Authors: Engelkemeir D.
Published: February 2005

A study of the response of the sodium iodide scintillation counter to photons in the energy range from 10 to 1500 kev has shown the presence of a significant nonlinearity. Response curves are given for a number of crystals of different dimensions.
Recording Magnetic-Resonance Spectrometer
Authors: Strandberg M. W. P. , Tinkham M. , Solt I. H. , Davis C. F.
Published: February 2005

Apparatus especially designed for studying electron paramagnetic resonance is described and discussed. A magnet of novel yokeless design is presented. Field stabilization and modulation procedure is considered. The microwave sample cavity is analyzed to determine conditions for optimum operation. The klystron stabilization problem is examined. Appropriate lumped circuits for low-frequency operation are described. The signal amplification and presentation system is treated in detail.
Recording Decay of Electron Density in Ionized Gases
Authors: Deakins G. E. , Crain C. M.
Published: February 2005

This paper describes a method for the measurement and photographic recording of electron density loss in an ionized gas utilizing a microwave system operating near 9400 Mc. The region between initial density level (upon removal of a 24.5-Mc ionizing voltage) and 500 μsec later was investigated. Examples of results obtained for commercial neon using this method of measurement are included. In general, it was observed that for commerical neon 90% of the electron density loss occurred within the first 250 μsec after removal of the ionizing voltage. The equipment used along with photographs of the arrangment, and the results obtained are discussed briefly.
Apparatus for Friction Studies at High Vacuum
Authors: Johnson Virgil R. , Vaughn George W. , Lavik Melvin T.
Published: February 2005

A friction test apparatus has been developed which permits accurate measurements under high vacuum. Sliding motion inside the vacuum chamber is accomplished by magnetic coupling through the chamber wall. The lag angle between the magnets, observed by means of stroboscopic illumination, measures the friction. Calibration of the magnetic coupling is obtained from the period of oscillation of the driven magnet with respect to the driving magnet.
Neutron Reflecting Mirrors for Determining Coherent Scattering Cross Sections
Authors: Heindl C. J. , Ruderman I. W. , Ostrowski J. M. , Ligenza J. R. , Gardner D. M.
Published: February 2005

Mirrors suitable for determining coherent cross sections by the neutron reflection technique are prepared by evaporating a sample on a flat electrochemically polished vanadium plate. Samples of separated isotopes as small as 20 mg may be used.
Mass Synchrometer
Authors: Smith Lincoln G. , Damm C. C.
Published: February 2005

A novel mass spectrometer with which masses of ions are determined in terms of high harmonics of their cyclotron frequencies is described from both experimental and theoretical viewpoints. Half-width resolution is adjustable electrically over a range of values presently between 10 000 and 25 000 at all mass numbers below 250. By means of a highly precise technique of matching peaks, relative doublet separations in frequency (Δf/f) exactly equal to those in mass (ΔM/M) are determined with great ease and accuracy on a ratio scaler. Masses have been determined with an accuracy of better than one part in 107, which is comparable with the best yielded by conventional instruments. Measurements should be of particular importance, even if of no greater precision than others, because the very different techniques employed make unlikely the occurrence of unsuspected systematic errors of the same nature as in other work. Sources of systematic error are discussed. It is believed that most of these have been eliminated, though avoidance of the not uncommon errors caused by differences in orbit distributions in doublets involving ions formed by dissociation has so far led to such large reductions of intensity as to restrict greatly the number of such important doublets for which reliable data have been obtainable. The synchrometer is apparently at a disadvantage to some deflection-type spectrometers in the matter of intensity, to some extent in principle and to a greater extent (to date) in practice. This disadvantage is enhanced by the difficulties of using an electron multiplier for detecting ions in strong magnetic fields. It is believed that the latter difficulties are not insuperable and it seems reasonable to expect that further work on increasing the intensity and improving the focusing of ions from the source will greatly enhance the number of results obtained. The possibilities of using the instrument for analytical purposes are interesting but so far largely unexplored.
Argonne 256-Channel Pulse-Height Analyzer
Authors: Schumann Robert W. , McMahon James P.
Published: February 2005

A 256-channel pulse-height analyzer using a magnetic core memory is now in use at the Argonne National Laboratory. This analyzer uses a form of the Wilkinson method of generating numbers in response to input pulses. These numbers are proportional to the amplitudes of the input pulses, and correspond to the channel numbers into which the individual counts are to be recorded. The digital data processing circuits comprise a simple computer, with an internal memory which can store 256 sixteen digit binary numbers. A cathode-ray tube display of the data in the form of a plot of counts versus channel number is available during and after operation. Permanent readout is in the form of a similar curve traced by a recording potentiometer. Printed decimal readout is also available. The normal average analyzer dead time is 80 μsec, and pulse rates in excess of 5 million per minute at the input circuit can be tolerated without appreciable data distortion.
1024-Channel Neutron Time-of-Flight Analyzer
Authors: Schumann Robert W.
Published: February 2005

A 1024-channel time-of-flight analyzer for recording data obtained in neutron time-of-flight experiments has been placed in operation at the Argonne National Laboratory. Channel widths are adjustable from ½ μsec to essentially any higher value. The analyzer dead time is 16 μsec following each recorded count. The storage circuits may be divided into two sections for recording events detected by two separate counters. The analyzer may also be divided into four groups of 256 channels each. These groups may be independently located in any time region up to 4096×T, where T is the channel width in use. Readout is by means of simultaneous teletype punched tape and analog pen recording. There is a linear cathode ray tube display of counts vs channel number. The device uses a magnetic core memory system similar to that used in the 256 channel pulse height analyzer described in the preceding article.
Apparatus for Obtaining Heating and Cooling Curves
Authors: Burkardt Lohr A. , McEwan William S. , Pitman Hayden W.
Published: February 2005

The apparatus described here permits the study of phase diagrams either by heating or cooling. One temperature control circuit permits a preset temperature gradient, either positive or negative, to be maintained between the sample and bath with the temperature of the bath being controlled by that of the sample. The appearance or disappearance of solids in the sample is followed by measurement of the light transmission of the sample. A second control circuit provides constant bath temperatures. A step-wise approach to the liquidus point, with the light transmission used to indicate the establishment of equilibrium between solid and liquid at each step, offers a means of determining this point under equilibrium conditions.
Faraday-Cup Monitors for High-Energy Electron Beams
Authors: Brown K. L. , Tautfest G. W.
Published: February 2005

Two Faraday-cup electron collectors have been developed which are capable of measuring the absolute integrated beam current of the Stanford linear accelerators to better than 0.5% at electron energies ranging from 4 to 300 Mev. A description of these instruments is given and complete design criteria are offered which allow the extension of the range to Bev energies.
Correction for Phosphor Backscattering in Electron Scintillation Spectrometry
Authors: Freedman M. S. , Novey T. B. , Porter F. T. , Wagner F.
Published: February 2005

An iterative numerical integration procedure has been developed to correct both beta spectra and differential beta-gamma directional correlations for the effects of finite instrument energy resolution including the effect of backscattering from a scintillation detector.

The method has been tested and found to reproduce the true spectral shape in the cases of Re186, Au198, Tl204, and to allow separation of composite beta spectra as in the case of W187. Application of the method is limited to maximum beta energies exceeding 200 kev.
Adiabatic Solution Calorimeter
Authors: Benson G. C. , Goddard E. D. , Hoeve C. A. J.
Published: February 2005

The solution calorimeter described previously [Rev. Sci. Instr. 26, 477 (1955)] has been modified by using an electrically heated shield for the adiabatic control. In this way the response time has been decreased by a factor of ten which greatly facilitates operation of the control. Under steady conditions the fluctuation in temperature between the calorimeter and its surroundings has been reduced from ±0.002 to ±0.001°C max. The calorimeter has a working range of 10° to 50°C.
Apparatus for Preparing Metal Powders Under Protective Atmospheres
Authors: Nurnberg H. L. , Domagala R. F. , Levinson D. W.
Published: February 2005

An apparatus originally conceived for directly preparing capillaries of powders of reactive alloys for x-ray study inspired the present device. The unit is simply a hermetically sealed chamber which is provided with a drive mechanism at the top, specimen and sight ports at the sides, and a funnel at the bottom. The drive mechanism is used to rapidly rotate a rotary cutter. Particles of any desired size are produced by a suitable choice of cutter and screen. The unit is extremely effective in its original role but has been used to prepare small quantities of powders of reactive alloys for other purposes, and is a versatile research tool.
Apparatus for Measuring Human Body Volume
Authors: Siri William E.
Published: February 2005

A means for measuring the density or the volume of the whole body is essential to reliable estimates of fat in humans. Although Archimedes' principle has often been employed to determine density directly, a method that is less demanding on the subject has been developed for measuring body volume. The apparatus is a closed-circuit system consisting of two chambers and utilizing a gas-dilution principle. With the subject in one chamber and helium in the other, the gases in the system are mixed. The helium concentration, measured by thermal conductivity, is related to the tissue volume displacement of the subject. The standard deviation in volume determination is estimated as ±0.12 liter.
Scanning Electrometer for Electron Microscopy
Authors: Bahr G. F. , Carlsson L. , Lomakka G.
Published: February 2005

For direct measurements of electron intensities in the image plane of the RCA electron microscope a scanning electrometer device has been designed. It consists of a probe and preamplifier, a mechanical drive, an amplifier, and a recording unit. A linear resolution of 0.06 to 0.92 μ is achieved. Sensitivity range is 10−12−10−11 amp.
Improved Demountable Crystallographic Rotating Anode X-Ray Tube
Authors: Taylor A.
Published: February 2005

An improved four-window demountable rotating anode x-ray tube fitted with rapidly interchangeable targets has been constructed. Compactness equal to that of a standard sealed-off tube has been achieved by the use of an improved re-entrant vacuum seal and bearing assembly. By employing peripherally directed water cooling in the anode behind the focal spot and a full wave rectified high tension supply, it has been possible to obtain greatly improved performance. With a copper target five inches in diameter rotating at 1000 rpm and with a focal spot 8×0.5 mm, the continuous load at 50 kv was 120 ma without any signs of target erosion.
Mechanically Sealed Beryllium Windows for Permanently Evacuated X-Ray Tubes
Authors: Perry John T.
Published: February 2005

A new type of permanently evacuated x-ray tube with a mechanically sealed low absorption beryllium window has been developed. The construction and low-voltage x-ray output measurements of this tube are presented and discussed.
Recording, Photometric Particle-Size Analyzer
Authors: Talvitie N. A. , Paulus H. J.
Published: February 2005

A recording, photometric particle-size analyzer has been developed which is useful in comparing the particle-size distributions of dusts in the subsieve range. The instrument follows the progress of the sedimentation of a suspension by means of a collimated beam. Provision for continuously varying the sedimentation depth allows analysis of the entire range within 1 hr. The optical system and temperature control were designed to increase the accuracy of analysis of the finer particles. A simplified system is given for calibrating the sedimentation curves in terms of particle size.
Optical Aspect System for Rockets
Authors: Kupperian James E. , Kreplin Robert W.
Published: February 2005

A simple electro-optical aspect system for use in upper air research rockets is described. Observations of the earth's albedo or night air glow along with observations of celestial bodies provide data from which the rocket's aspect is determined. A mechanical computer is described which greatly simplified aspect data reduction.