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Aug 1951

Volume 22, Issue 8, pp. 551-658

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A Comprehensive Counting System for Nuclear Physics Research Part IV. Introduction to Pulse Amplitude Analyzers

N. F. Moody, W. J. Battell, W. D. Howell, and R. H. Taplin

Rev. Sci. Instrum. 22, 551 (1951); http://dx.doi.org/10.1063/1.1746003 (13 pages) | Cited 5 times

Online Publication Date: 20 December 2004

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In scientific research, pulse amplitude or temporal distribution is often the analog of the phenomenon under investigation. Particularly is this true in nuclear studies, where pulse amplitude can be made proportional to energy and classification on an amplitude basis yields the energy spectrum. The present paper gives an outline of pulse amplitude analyzing equipment and indicates that for pulse widths of one microsecond and larger, as distinct from those in the millimicrosecond region, the thermionic diode leaves little to be desired as a voltage discriminating element.

The Lorentz Factor for the Buerger Precession Method

Jürg Waser

Rev. Sci. Instrum. 22, 563 (1951); http://dx.doi.org/10.1063/1.1746004 (4 pages) | Cited 14 times

Online Publication Date: 20 December 2004

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The Lorentz factor for the Buerger precession method is derived. It turns out that the angular velocity of the motion of the reciprocal lattice through the sphere of reflection is not uniform as hitherto accepted. The Lorentz factor thus depends explicitly on all three cylindrical coordinates ξ, ζ, τ of the reciprocal lattice point under consideration and not on only as ξ and ζ.

Lorentz and Polarization Correction for the Buerger Precession Method

Jürg Waser

Rev. Sci. Instrum. 22, 567 (1951); http://dx.doi.org/10.1063/1.1746005 (2 pages) | Cited 21 times

Online Publication Date: 20 December 2004

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The reciprocal of the product of the Lorentz factor and the polarization factor is calculated for the zero level and math = 30∘.

Forced Betatron Oscillation in a Synchrotron with Straight Sections

Nelson M. Blachman

Rev. Sci. Instrum. 22, 569 (1951); http://dx.doi.org/10.1063/1.1746006 (3 pages) | Cited 1 time

Online Publication Date: 20 December 2004

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The effect of azimuthal variation in the height of the magnetic median plane on the vertical oscillations of a particle in a synchrotron having four straight sections is studied, particularly in the neighborhood of resonance between the frequency of these oscillations and the frequency of revolution. It is found that fourier analysis, which is needed in the case of a circular magnet, is replaced by analysis using modified sine and cosine functions. This investigation also applies to the effect on the radial betatron oscillations of azimuthal variation in the equilibrium radius.

Calorimetric Determination of the Energy Flux of 22.5‐Mev X‐Rays

J. S. Laughlin and J. W. Beattie

Rev. Sci. Instrum. 22, 572 (1951); http://dx.doi.org/10.1063/1.1746007 (3 pages) | Cited 4 times

Online Publication Date: 20 December 2004

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A sensitive method of calorimetrically measuring the energy flux of an x‐ray beam is described. Thermistors are employed as the temperature‐sensitive elements and are embedded in the irradiated material in a calorimeter. Details and results of the application of this technique to a betatron x‐ray beam are described. This method can be applied to x‐ray beams of other energies and does not require high intensities.

An Automatic Plate Counter

Jerome L. Lerner and Donald F. Uecker

Rev. Sci. Instrum. 22, 575 (1951); http://dx.doi.org/10.1063/1.1746008 (4 pages)

Online Publication Date: 20 December 2004

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A versatile counter that automatically sorts sample plates into several groups according to the radioactivity of the plates is described. Details are given for a counter specifically intended to minimize the tedious job of counting decontaminated plates for background.

Pulsed Air Core Series Disk Generator for Production of High Magnetic Fields

Robert I. Strough and Erwin F. Shrader

Rev. Sci. Instrum. 22, 578 (1951); http://dx.doi.org/10.1063/1.1746009 (5 pages) | Cited 2 times

Online Publication Date: 20 December 2004

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The possibility of the efficient storage of large amounts of energy and its subsequent rapid conversion into useful electromagnetic energy has been studied. Efficient and economical storage of energy is possible in the form of kinetic energy of rotation. Conversion of energy stored in this manner into electromagnetic energy has been accomplished by using the rotating mass as the armature of a series wound homopolar generator. A successful prototype generator has been built and its performance compared with the theoretical operation of such a device. The prototype generator was capable of storing 29,000 joules when operating at 20,000 rpm. When it is operated under short circuit conditions, a current pulse of 56,000 amperes maximum is obtained in the single‐turn series field coil. Liquid mercury brushes were developed especially for this generator, since very low circuit resistance is required for self‐excited operation. The starting of the flow of mercury in the brush system serves to start the generator in operation. The possible further development and uses of this generator are discussed.

Analysis of Errors in Measuring Thermal Conductivity of Insulating Materials

Edward V. Somers and Joseph A. Cyphers

Rev. Sci. Instrum. 22, 583 (1951); http://dx.doi.org/10.1063/1.1746010 (4 pages) | Cited 14 times

Online Publication Date: 20 December 2004

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Thermal conductivity measurements made by the guarded‐hot‐plate method are subject to error from heat loss by convection at the exposed edges of the sample. Analytical solutions are found and plotted to show the maximum errors for square and round samples in apparatus of various dimensions.

Loop‐Line Windowless Flow Geiger Counter

P. E. Damon

Rev. Sci. Instrum. 22, 587 (1951); http://dx.doi.org/10.1063/1.1746011 (3 pages)

Online Publication Date: 20 December 2004

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The instrument described is of simple and rugged design. The anode is a wire loop, and the cathode includes a grounded line wire which electrically shields the sample. The line wire, when properly placed, provides greater stability and freedom from spurious effects due to the accumulation of a charge on the sample. The geometry is essentially 2π. The instrument may be used for the counting of alpha‐ as well as soft beta‐particles. It is self‐shielded.

An Apparatus for Measuring the Rates of Some Rapid Reactions

C. Dana McKinney and Martin Kilpatrick

Rev. Sci. Instrum. 22, 590 (1951); http://dx.doi.org/10.1063/1.1746012 (8 pages) | Cited 1 time

Online Publication Date: 20 December 2004

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As a means of studying the kinetics of rapid reactions in which a gas is evolved, a constant volume reactor has been designed. This reactor employs a static technique in which the reaction is followed by the increase in pressure as the gas is evolved. The apparatus is capable of contacting 1 ml of one reactant with 25 ml of a second reactant and obtaining effective mixing in less than 10 milliseconds.
The pressure‐sensitive device is a strain gauge, the output of which is plotted as a function of time by a cathode‐ray oscilloscope. The apparatus was tested for complete mixing and desaturation of the gas from the liquid phase by means of a reaction known to be very fast. The reaction chosen was the homogeneous reaction between the permanganate ion and hydrogen peroxide in acid solution.
The reaction between lithium borohydride and sulfuric acid was found to have a half‐time of approximately one second. The half‐time of the reaction between sodium‐potassium alloy and ethanol was only a few milliseconds. The reactions of aluminum borohydride and ethylaluminum sesquihydride with water and with acids also were studied.

Continuous Purification of Hydrogen in a Large Electron‐Pulse Chamber

W. N. English

Rev. Sci. Instrum. 22, 598 (1951); http://dx.doi.org/10.1063/1.1746013 (3 pages)

Online Publication Date: 20 December 2004

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A hot uranium purifier for hydrogen (or deuterium) has been constructed which will remove relatively large amounts of negative ion forming impurities such as O2, Cl2, H2O, thus permitting electron pulse collection without any elaborate outgassing procedure. The method has been tested at 6 atmospheres hydrogen pressure by observing the pulse distribution from a Pu239 α‐source in the chamber and plotting the ``most‐probable‐pulse‐amplitude'' against purifying time. A ``purifying time constant'' of about two days was obtained.

A Dee Biasing System for a Frequency Modulated Cyclotron

L. L. Davenport, L. Lavetelli, R. A. Mack, A. J. Pote, and N. F. Ramsey

Rev. Sci. Instrum. 22, 601 (1951); http://dx.doi.org/10.1063/1.1746014 (4 pages)

Online Publication Date: 20 December 2004

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The requirements that must be met by a satisfactory dee biasing system are outlined. A successful and simple means of meeting these requirements is described.

A Microphotometric Area Determinator

Harvey Walker and Quentin Van Winkle

Rev. Sci. Instrum. 22, 604 (1951); http://dx.doi.org/10.1063/1.1746015 (3 pages)

Online Publication Date: 20 December 2004

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The Knorr‐Albers microphotometer has been modified to permit the application of the trapezoidal rule to the measurement of the true areas of photographically recorded figures of irregular shape. These modifications include a vertical plate‐elevating mechanism and a timer controlled by a cam and roller microswitch.

Analysis of High Energy Proton Spectra by Means of a Stack of Photographic Plates

Darcy Walker

Rev. Sci. Instrum. 22, 607 (1951); http://dx.doi.org/10.1063/1.1746016 (5 pages) | Cited 1 time

Online Publication Date: 20 December 2004

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Stacks of photographic plates have been used to analyze the continuous spectrum of high energy protons emitted by a carbon target bombarded with γ‐rays from an electron synchrotron. The planes of successive plates in a stack lay at 30° to a line through plate and target centers, and the plates were interleaved with aluminum absorbers. The numbers of proton tracks per square cm in the emulsions of successive plates yield an integral spectrum of the protons. Protons with energies up to more than 120 Mev were present when the synchrotron was operated at 195 Mev. The effects of multiple scattering of the protons in the stacks are discussed, and it is shown how the tracks of protons originating from the target can be distinguished clearly from a background of randomly oriented tracks.
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Erratum: A Wide Range Mechano‐Electronic Transducer for Physiological Applications

S. A. Talbot, J. L. Lilienthal, J. Beser, and L. W. Reynolds

Rev. Sci. Instrum. 22, 611 (1951); http://dx.doi.org/10.1063/1.1746017 (1 page)

Online Publication Date: 20 December 2004

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Abstract Unavailable

Magnet Current Stabilizer

H. S. Sommers, P. R. Weiss, and W. Halpern

Rev. Sci. Instrum. 22, 612 (1951); http://dx.doi.org/10.1063/1.1746018 (7 pages) | Cited 8 times

Online Publication Date: 20 December 2004

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The design and performance of a feedback amplifier for the precision control of the current through a 40‐kw magnet is described. The system uses the difference between the IR drop in a standard resistor and a preset potentiometer voltage to control the current. The principal components are a high gain vibrator amplifier and a stabilized power amplifier incorporating a commercial motor‐generator set. Current fluctuations are kept below one part in a million.
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Rapid and Sensitive Spectrophotometry. I. The Accelerated and Stopped‐Flow Methods for the Measurement of the Reaction Kinetics and Spectra of Unstable Compounds in the Visible Region of the Spectrum

Britton Chance

Rev. Sci. Instrum. 22, 619 (1951); http://dx.doi.org/10.1063/1.1746019 (9 pages) | Cited 43 times

Online Publication Date: 20 December 2004

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The present form of the accelerated and stopped flow methods for the measurement of the reaction kinetics and spectra of intermediate compounds in biochemical reactions is described. This apparatus gives satisfactory records with only a few tenths of a cubic centimeter of 2×10−7M iron enzyme solution and covers a time range from a few milliseconds to several minutes. The wavelength range is 370 to 600 mμ, and the spectral interval is 7.5 mμ. The error in optical density measurement is about 1×10−5 corresponding to a signal‐to‐noise ratio of 5×104 for a response time of 1 sec over the wavelength range of 380–580 mμ. The present performance and range of usefulness considerably exceed that reported previously.

Rapid and Sensitive Spectrophotometry. II. A Stopped‐Flow Attachment for a Stabilized Quartz Spectrophotometer

Britton Chance and Victor Legallais

Rev. Sci. Instrum. 22, 627 (1951); http://dx.doi.org/10.1063/1.1746020 (8 pages) | Cited 7 times

Online Publication Date: 20 December 2004

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The stabilization of the light sources and the photocell circuits of a quartz spectrophotometer and the design of suitable stopped flow apparatuses are described. The latter have been designed for 1.6‐ and 10‐mm optical paths and have been shown to give rapid mixing (<0.1 sec). Errors of optical density measurement are diminished by rectangular observation tubes, and errors of extinction coefficients are minimized by a narrow spectral interval (less than 2 mμ from 230–600 mμ). The error of optical density caused by the photoelectric circuits is about 1×10−4 for a response time (10–90 percent) of 1 sec. The application of this apparatus to the measurement of rapid chemical reactions in the visible and ultraviolet regions is described.

Rapid and Sensitive Spectrophotometry. III. A Double Beam Apparatus

Britton Chance

Rev. Sci. Instrum. 22, 634 (1951); http://dx.doi.org/10.1063/1.1746021 (5 pages) | Cited 80 times

Online Publication Date: 20 December 2004

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An apparatus for accurately timing the sequence of spectroscopic events in turbid suspensions of the cytochrome oxidase system has been developed. This apparatus measures simultaneously small optical density changes occurring at two wavelengths in the visible region with a small spectral interval in spite of the large scattering of light by the heart muscle suspensions. The cross talk between the two channels corresponds to an optical density change of less than 5×10−4. Transients arising from the modulation and demodulation processes cause no difficulty. The error of optical measurements caused by the noise level in the photocurrent is 2×10−4 for a rise time (10–90 percent) of 1 sec. Some typical experimental results are included.

Scintillation Detector for the Localization of Radioactive Concentrations in Vivo

William B. Ittner and M. Ter‐Pogossian

Rev. Sci. Instrum. 22, 638 (1951); http://dx.doi.org/10.1063/1.1746022 (4 pages)

Online Publication Date: 20 December 2004

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A radiation detection instrument, employing a large naphthalene‐anthracene crystal and a concentric conical collimator, for the localization of radioactive concentrations at a distance is described. A simplified method of obtaining the general outline of volumetric distributions of radioiodine is presented.

A Magnetic Float Method for Determining the Densities of Solutions

D. A. MacInnes, Margaret O. Dayhoff, and B. Roger Ray

Rev. Sci. Instrum. 22, 642 (1951); http://dx.doi.org/10.1063/1.1746023 (5 pages) | Cited 12 times

Online Publication Date: 20 December 2004

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A method for determining the densities of liquids is described in which a float containing a magnet is utilized. The conditions under which the submerged float would remain poised are found by adding weights and by observing the effect of currents through a solenoid. The method may be adapted to the measurement of the densities of solutions at a series of increasing concentrations by forming the solutions directly in the vessel containing the float.

A Scintillation Counter for the Relative Determination of X‐Ray Intensities in Radiological Work

Michel Ter‐Pogossian and William B. Ittner

Rev. Sci. Instrum. 22, 646 (1951); http://dx.doi.org/10.1063/1.1746024 (3 pages) | Cited 1 time

Online Publication Date: 20 December 2004

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An instrument is described for determining accurately the intensity of an x‐radiation by direct reading. This instrument consists in a small potassium iodide crystal which fluoresces under the action of high energy photons. The light thus emitted is ``piped'' by means of a Lucite rod to a photomultiplier tube. The current generated in the tube is measured by a microammeter.
A series of tests on the energy dependence of this detector are reported. It is concluded that the instrument described is suitable for the determination of isodose charts.

Vibrating Plate Transducers for Frequency Studies of the Breakdown Rate of Biological Cells

Eugene Ackerman

Rev. Sci. Instrum. 22, 649 (1951); http://dx.doi.org/10.1063/1.1746025 (3 pages) | Cited 2 times

Online Publication Date: 20 December 2004

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Transducers are described giving audio outputs greater than 0.1 watt/cm2, sufficient for cellular disruption. A method of measuring the spatial average of the transducer velocity amplitude is discussed. The apparatus is suitable for studies of the effect of frequency and velocity amplitude on the breakdown rate of biological cells.

Notice

Rev. Sci. Instrum. 22, 651 (1951); http://dx.doi.org/10.1063/1.1746026 (1 page)

Online Publication Date: 20 December 2004

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Abstract Unavailable
back to top New Instruments

New Instruments

W. A. Wildhack

Rev. Sci. Instrum. 22, 652 (1951); http://dx.doi.org/10.1063/1.1746027 (7 pages)

Online Publication Date: 20 December 2004

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Abstract Unavailable
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