bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nomographs for the Determination of Wavelength for Highest Angle X-Ray Diffraction
Authors: Muldawer L. , Feder R. 
Published: February 2005

A single operation technique is presented for the determination of wavelength for highest angle diffraction of cubic materials. This method makes use of a chart with the lattice parameter as ordinate and (λ/2 sinθ) as abscissa, lines being drawn for each (h2+k2+l2).
For noncubic materials, a chart is prepared with lattice spacing as ordinate and (1/sinθ) as abscissa, lines being drawn for each wavelength. Separate settings must be made for each spacing in this second case.
Automatic Balance for Measurement of the Strength of Glass Fibers
Authors: Sinclair David 
Published: February 2005

The semiautomatic balance used to measure the tensile strength and Young's modulus of glass fibers when bent into a loop has been made fully automatic. A differential transformer and servomotor are used to apply chain-weight as the tension in the looped fiber is increased by the loading motor.
All measurements needed to calculate the tensile strength and Young's modulus are automatically recorded on the drum chart driven by the loading motor. The maximum tensile stress in the looped fiber at the instant of break is proportional to the vertical motion of the recording pen, and the maximum strain is proportional to the rotation of the drum.
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.
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.
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.
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.
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.
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.
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.
Ion Phase Measurements on the Birmingham Cyclotron
Authors: Konrad M. 
Published: February 2005

The ion phase in the internal beam of the Birmingham cyclotron at distances from the ion source from 8 mm up to 69 cm has been determined by measurements of the target current waveform. The equipment consisted of a screened target and a specially built oscilloscope based on the sampling technique. The results obtained are discussed and compared with theory.
Ions are grouped in phase at early stages of acceleration over approximately 20 electrical degrees, which is about 5 times larger than predicted by the uniform electric field approximation. At later stages the measured phase changes are in good agreement with Rose's equation.
Vernier Chronotron
Authors: Lefevre Harlan W. , Russell James T. 
Published: February 2005

The instrument described is a multichannel time interval analyzer with digital output for use in the millimicrosecond region. The analyzer consists of two circulating transmission lines with a single fast coincidence circuit between them and associated gating circuits. Each circulating line is a precisely trimmed coaxial cable with its ends joined by a two-stage noninverting saturating amplifier. A circulating pulse delivers time marks to the input of the coincidence circuit. By making the circulation periods of the two lines slightly different, the time marks are made to arrive at slightly different frequencies. The instrument is a true vernier. To measure an interval it is only necessary to count the number of circulations before coincidence and multiply by the difference in circulation period of the lines. A commercial 256-channel magnetic core memory is used for storage.
The circuit of the instrument is described. A method is described for predicting circulation threshold, growth to equilibrium, and equilibrium amplitude of a circulating pulse from the amplifier transfer characteristic. Data are presented which indicate the linearity, stability, and time resolution of the instrument.
High-Q Stark Cavity Absorption Cell for Microwave Spectrometers
Authors: Dymanus A. 
Published: February 2005

Design considerations, description, and some data on the performance are given of a large pillbox-shaped Stark cavity absorption cell for the 1.25-cm wavelength region. The cavity can be used in any TE0m1 mode with m ranging from about 5 to about 12 and its most prominent features are: high loaded Q factor (∼5×103−104), good electric insulation (at pressures below 4×10−2 mm Hg Stark voltages up to 3000 v can be applied), low Stark field inhomogeneity (diameter to length ratio 15–20), large band width (from about 18 to about 28 kMc), and low mode density. No cross-mode resonances occur and the only undesired modes excited appreciably are the TE2m1 ones. When used in transmission only the TE0m1 modes couple to the output.
The cavity can be used at the same time as a reference cavity of a Pound-type klystron frequency stabilizer. The klystron frequency will then automatically follow the resonance frequency of the cavity over a frequency interval up to 400 Mc.
Cosmic-Ray Instrumentation in the First U. S. Earth Satellite
Authors: Ludwig George H. 
Published: February 2005

The first U. S. satellite, 1958 Alpha (Explorer I) carried instrumentation to measure cosmic-ray intensity, micrometeorite impacts, and temperatures within the satellite. The instrumentation was designed with emphasis on conservation of electrical power, on stable and reliable operation, on operation over a wide range of temperatures, and on compactness and mechanical ruggedness.
The cosmic-ray instrumentation in 1958 Alpha operated according to expectations, providing several hundred recordings of data received during transits over ground stations. These data led to the discovery of a belt of high-intensity radiation around the earth.
Volume and Index Measurements of Blood Cells with a Recording Diffractometer
Authors: Polanyi Michael L. 
Published: February 2005

The measurement of the diameter and index of refraction of spheres whose diameter is larger than the wavelength of the light used and whose index, relative to the surround, is close to unity is described. The measurements are based on the angular position of the first dark ring and first bright ring in the Fraunhofer diffraction pattern.
The instrument is of novel design, its main advantages being that all the light scattered under a given angle is used in the measurement and that the peaks and valleys in the recorded graph are very prominent and easy to locate. The resolving power of the instrument is inversely proportional to the diffracting angle. The use of the Van de Hulst approximate diffraction theory for obtaining the diameter and the index of the diffracting spheres from the recorded diffraction pattern is described in detail. Application to the measurement of human blood cells, the main purpose of this work, is also completely worked out and experimental results are given. Very good agreement between the mean cell hemoglobin as measured with the standard procedures and the one described here has been found.
Techniques of Cathode Temperature Measurements as Applied to Commercial Cathode-Ray Tubes
Authors: Coppola P. P. 
Published: February 2005

Thermocouple, optical pyrometer, and retarding potential techniques for the measurement of cathode temperatures in commercial cathode-ray tubes have been investigated to determine their relative merits, limitations, and corrections.
The thermocouple method is accurate and reliable provided necessary lead loss corrections are made. Application of this method to commercial tubes is limited by the expense involved. The optical pyrometer method is questionable when applied to an oxide-cathode coating due to considerable spread in spectral emissivity data; however, the method is reliable when applied to the cathode base nickel. The retarding potential method shows good correlation to the other methods and is directly applicable to commercial tubes with no modifications required. However, limitations are imposed by a number of factors, notably the stability of cathode emission and leakage current levels.
Economical Liquid Helium Cryostat and other Cryogenic Apparatus
Authors: Whitehouse J. E. , Callcott T. A. , Naber J. A. , Raby J. S. 
Published: February 2005

A liquid helium cryostat which is inexpensive and simple to build is described. Its main features originate from the use of spherical metal floats arranged concentrically to form the body of the vessel. The tailpiece used with the cryostat provides for liquid helium to circulate in the sample holder. A mechanical valve allows the flow of liquid to be interrupted so that temperatures above 4.2°K may be maintained. A typical combination of cryostat and tailpiece has a capacity for 2 liters of liquid helium and will store this charge for nearly 4 days.
A liquid nitrogen vacuum system cold trap and a liquid helium transfer tube are also described. The former also features the use of metal floats in its construction. The transfer tube has a degree of flexibility and a very small outer diameter.
A Sensitive Direct Current Electrical Integrator
Authors: Gilbert R. W. 
Published: February 2005

A permanent magnet-movable coil d.c. instrument mechanism is used as an oscillating relay for time integration of d.c. potential. It is operated in conjunction with an input-reversing relay and a vacuum tube circuit to promote oscillation, the frequency of which is proportional to the input potential, and the number of oscillations is related to the potential-time integral.
In operation the accuracy of integration is within 1 percent over an input-level ratio of over 100. And the energy demand from the source of input is comparable or less than that required to operate conventional d.c. indicating instruments.
New Meters Employing Light-Sensitive Cells for the Measurement of Erythemal Energy
Authors: Kerr George P. 
Published: February 2005

The applications of some well-known principles to the measurement of erythemal energy with light-sensitive cells are described. In one meter described the differential current of two cells is registered, and by selection of the proper filter for each cell, this current can be made a measure of the intensity of radiant energy weighted approximately according to its erythemal efficiency.
In the other meter, the radiant energy to be measured is incident on a filter which transmits ultraviolet energy but absorbs visible energy almost completely. A phosphor having a suitable spectral sensitivity is then activated, and the resulting fluorescent light is transmitted to the cell through filters which totally absorb ultraviolet energy. The spectral response of the device is then almost identical to that of the phosphor.
Quantitative data are presented on the spectral and absolute sensitivities of the meters.
Studies of Thermal Injury. VIII. Automatic Recording Caloric Applicator and Skin-Tissue and Skin-Surface Thermocouples
Authors: Henriques F. C. 
Published: February 2005

An automatic recording caloric applicator is described and evaluated. This apparatus enables the skin surface to be brought immediately to and maintained at a constant, predetermined temperature. Further, it continuously records the rate of the perpendicular flow of heat through this skin site during the entire heat exposure.
A 120×0.04-cm stainless-steel hypodermic needle thermocouple is described and evaluated. This instrument was designed to enable a 10- to 25-cm lateral penetration of cutaneous and subcutaneous tissue and, therefore, is especially suited to the measurement of temperature changes within a skin site subjected to the caloric applicator. In view of its small diameter, maneuverability, accuracy, and non-fragility, this trocar is well suited for the measurement of tissue temperatures in general.
A 0.05-mm wire thermocouple of simple design, which was constructed to measure ``true'' skin-surface temperature, is described and evaluated.
A Counter for Low Energy Ionizing Particles
Authors: Thomas H. C. , Underwood N. 
Published: February 2005

A counter which combines large solid angle, low operating voltage, ease of changing source, and ability to detect particles of very low energy is described.
By means of a revolving plate a sample may be rotated to a position inside the counting chamber through which helium is slowly passing. A large solid angle with low operating voltage is achieved by placing side by side several semicylindrical cathodes whose central wires are electrically connected.
Fe55, which has a half-life of four years, was used as a sample with which to examine the operational characteristics of the counter.
The Photo-Multiplier Radiation Detector
Authors: Marshall Fitz-Hugh , Coltman J. W. , Bennett A. I. 
Published: February 2005

The photo-multiplier radiation detector consists of a commercial multiplier photo-tube arranged to register the scintillations produced in a fluorescent screen by radiation quanta. The signal pulses thus obtained are large for alpha-particles and other high velocity ions, much weaker for x-rays, gamma-rays, and high velocity electrons. The method is limited by the presence of noise pulses caused by electrons thermally emitted at the photo-cathode; signal pulses can be discriminated from noise pulses only to the extent that their amplitudes are greater. Satisfactory detection of the weaker signal pulses has been accomplished by careful attention to (1) selection of photo-tubes, (2) choice of fluorescent screen, (3) efficient collection of light, and (4) proper circuit design.
The new detector is especially suited to narrow-beam measurements where high counting rates are desired. However, it compares favorably with conventional detectors even when low counting rates and weak signal pulses are involved. The detector is rugged and fast, requires no special thin-window technique, and shows high efficiency. The primary detecting medium, being a solid, has high absorption and is well defined in position.
This article includes full construction details, an analysis of performance characteristics, particularly with weak signal pulses, and numerous suggestions for further improvement.
A Proton-Controlled Magnetic Field Regulator
Authors: Packard Martin E. 
Published: February 2005

A magnetic field discriminator is described which uses the nuclear induction signal from protons to give a ±75-volt change of d.c. voltage for a ±0.3-gauss change in magnetic field without using direct coupled amplifiers.
An ordinary degenerative current regulator with the addition of information from the magnetic field discriminator will control a magnetic field to within 0.02 gauss for a 10 percent line voltage change or for normal changes in magnet geometry.
The magnitude of the magnetic field is maintained in terms of a frequency, the value of which gives the absolute magnitude of the magnetic field.
Some Geiger-Müller and Proportional Counters of Spherical Shape
Authors: Salvini Giorgio 
Published: February 2005

A Geiger-Müller counter with a spherically shaped cathode is described. The pulse shape from this counter is similar to that of cylindrical counters. It may be used satisfactorily in ordinary coincidence work.
Some of the counters, slightly modified to avoid spurious discharge, were filled with boron trifluoride and used as proportional counters for detection of neutrons.