RSI Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

Aug 1950

Volume 21, Issue 8, pp. 681-778


The Measurement of Rates of Flow of Gases by Wet Test Meters

Robert L. Burwell, Max Metlay, and Frank W. Pfohl

Rev. Sci. Instrum. 21, 681 (1950); http://dx.doi.org/10.1063/1.1745690 (2 pages)

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
Rates of flow of gases may be measured to an accuracy of better than 0.1 percent with properly modified and operated wet test meters. The period of a single rotation is measured by an electric stop clock. The instrument is not an absolute one but must be calibrated by a meter prover. A suitable prover is described. Within rather wide limits the calibration is independent of flow rate. The instrument may be used for direct measurement or for calibrating other types of flow meters.

Solution of Simultaneous Equations through Use of the A.C. Network Calculator

L. M. Haupt

Rev. Sci. Instrum. 21, 683 (1950); http://dx.doi.org/10.1063/1.1745691 (4 pages) | Cited 1 time

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
Kirchhoff's law equations may be written for any electrical network. Conversely, it is usually possible to find an electrical network whose Kirchhoff law equations are similar to the given set of simultaneous equations. The solution to the equations may then be found by measuring the corresponding quantities in this analogous network. The a.c. network calculator is adaptable to this method of solving equations. Presented here are the fundamentals of finding the correct electrical network for a given set of simultaneous equations.

Arithmetic Operations in a Binary Computer

Robert F. Shaw

Rev. Sci. Instrum. 21, 687 (1950); http://dx.doi.org/10.1063/1.1745692 (7 pages) | Cited 1 time

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
The application of binary arithmetic in the computing circuits of a high speed digital computer is discussed in detail. The discussion covers, with numerous examples, the use of complements to represent negative numbers, the corrections necessary in the multiplication process as a result of the use of complements, and additional modifications of the process to simplify mechanization. A special division method well‐adapted to automatic computer use is described, and round‐off procedures are noted briefly. The article is concluded with a discussion of the storage of negative numbers as absolute values with a sign rather than in complement form.

A Recording Polarimeter

Gabor B. Levy, Philip Schwed, and David Fergus

Rev. Sci. Instrum. 21, 693 (1950); http://dx.doi.org/10.1063/1.1745693 (6 pages) | Cited 7 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
A recording polarimeter has been constructed. The principle of operation is essentially the replacement of an operator in conventional visual polarimetry by a photoelectric servo system. A photo‐multiplier tube is used which, in conjunction with a mechanical chopping system, delivers an alternating current signal proportional to the unbalance. The latter is filtered and amplified and actuates a servo mechanism. The precision of the system is ±0.005° for static balance and the speed about 0.5° per minute. Hence the arrangement compares favorably with ordinary visual operation. The construction of the instrument is discussed briefly and its performance is illustrated by examples.

High Pressure Ionization Chamber Counters and Their Use

R. Wilson, L. Beghian, C. H. Collie, H. Halban, and G. R. Bishop

Rev. Sci. Instrum. 21, 699 (1950); http://dx.doi.org/10.1063/1.1745694 (7 pages) | Cited 5 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
Certain new developments in ionization chamber technique are described. Ionization chamber counters have been designed to operate with fillings of H2, D2, or CH4 to pressures of 35 atoms. with simple filling techniques. The design, characteristics, and uses of these counters are described.

The Chalk River Single Crystal Neutron Spectrometer

D. G. Hurst, A. J. Pressesky, and P. R. Tunnicliffe

Rev. Sci. Instrum. 21, 705 (1950); http://dx.doi.org/10.1063/1.1745695 (8 pages) | Cited 10 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
A single crystal neutron spectrometer has been constructed which shows improvement in resolution and intensity over previously described instruments. This has been made possible by the high flux available from the Chalk River heavy water reactor. The instrument can be operated automatically.
Mechanical design, crystals, resolution and the contamination of the spectrum by higher orders are discussed.

Ring Focus in a Thin Magnetic‐Lens Beta‐Ray Spectrometer

Joseph M. Keller, Ernest Koenigsberg, and Arthur Paskin

Rev. Sci. Instrum. 21, 713 (1950); http://dx.doi.org/10.1063/1.1745696 (9 pages) | Cited 13 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
The paths of electrons in a thin magnetic‐lens type of spectrometer are described by a non‐linear differential equation. The equation was numerically integrated to obtain a set of electron trajectories originating from a point source on the axis of the instrument. Trajectories for off‐axis sources were approximated. On the basis of these trajectories, the location and some properties of ring focus were studied. Theoretically calculated line shapes are compared for axial and ring focus. For reasonable values of resolution, the transmission of the spectrometer would be roughly doubled by performing the momentum discrimination by a ring focus baffle instead of by a small counter on the axis.

Lens Tester for Photographic Lenses

F. G. Back

Rev. Sci. Instrum. 21, 722 (1950); http://dx.doi.org/10.1063/1.1745697 (3 pages)

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
Testing lenses, particularly photographic lenses, in a simple, fast, and accurate manner is quite a difficult problem. One of the solutions to this problem is a lens tester which is basically a modified autocollimator with a built‐in color filter arranged in conjunction with an assembly unit consisting of an adjustable microscreen and a lens holder. This latter unit may be rotated about an axis perpendicular to the optical axis of the instrument, giving an immediate reading of the tangential and sagittal foci. By means of this instrument it is possible to determine: (1) the flange focal distance, (2) the shift of axial focus with respect to the lens aperture, (3) longitudinal chromatic aberration, (4) tangential and sagittal foci for any angular distance from the axis and for any aperture, and (5) all these readings for various color bands. This new instrument makes possible the immediate reading of the results without further computation. The determination of the nodal point and the focal length for extra‐axial aberrations is unnecessary. Built‐in color filters allow testing for chromatic aberrations. Because of a special microscreen and reflection‐free beam splitter arrangement, this instrument gives satisfactory readings also for small apertures.

Improvements in Mass Spectrometers for the Measurement of Small Differences in Isotope Abundance Ratios

C. R. McKinney, J. M. McCrea, S. Epstein, H. A. Allen, and H. C. Urey

Rev. Sci. Instrum. 21, 724 (1950); http://dx.doi.org/10.1063/1.1745698 (7 pages) | Cited 147 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
A Nier‐type mass spectrometer and its associated electronic units have been constructed for the purpose of measuring small variations in the abundances of oxygen of mass 18 and of carbon of mass 13 in carbon dioxide, and of oxygen of mass 18 in oxygen gas, to an accuracy of ±0.01 percent of the abundance of these isotopes.
The electronic units of the necessary stability for this degree of accuracy are described. A gas feed system is described which permits fast alternate introduction of the sample of gas to be analyzed and a standard gas into the mass spectrometer. All measurements of the variation in the abundance of the oxygen and carbon isotopes are made with reference to a standard.

Vacuum Tests of Rubber, Lead, and Teflon Gaskets and Vinyl Acetate Joints

Robert W. Cloud and Sanborn F. Philp

Rev. Sci. Instrum. 21, 731 (1950); http://dx.doi.org/10.1063/1.1745699 (3 pages) | Cited 3 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
Rubber, Teflon, and vinyl acetate sealed systems are compared, by an approximately quantitative method, with a lead gasket sealed system which is shown to give off negligible gas at room temperature. Rubber is shown to evolve relatively large amounts of gas with an apparent vapor pressure above a micron at room temperature and about 0.1 micron at liquid air temperature. Continuous pumping for several days produces no improvement, nor does the use of metal‐to‐metal joints. Vinyl acetate joints are shown to improve with pumping over a period of several days, reaching a condition exhibiting an ``apparent vapor pressure'' of 5×10−7 mm of mercury, or less, at room temperature. Heating to 45°C raises the apparent vapor pressure to the 10−5 mm range, and heating to 100° raises the apparent vapor pressure to the micron range. If this behavior is caused by the vapor pressure of the vinyl acetate itself, continued baking in vacuum will, of course, produce no improvement.

Boron Trifluoride Proportional Counters

I. L. Fowler and P. R. Tunnicliffe

Rev. Sci. Instrum. 21, 734 (1950); http://dx.doi.org/10.1063/1.1745700 (7 pages) | Cited 13 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
Boron trifluoride proportional counters of calculable efficiency for neutron beam measurements are described. It has been found possible to obtain excellent pulse‐size distributions with a filling of 60 cm of purified BF3 by ``soaking'' the counters for a long time (up to three months) with BF3 before putting in the final filling. These fillings are stable. Fillings of less than 5 cm BF3 made up to 50 cm with argon have also been studied. With these fillings the pulse‐size distributions are very good for both beam and total irradiation conditions. A discussion of the counter efficiencies with particular reference to end correction is given.

The Design of a Magnetic Focusing Coincidence Spectrometer

C. M. Fowler and R. G. Shreffler

Rev. Sci. Instrum. 21, 740 (1950); http://dx.doi.org/10.1063/1.1745701 (7 pages) | Cited 7 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
Design and operating features are described for a semi‐circular magnetic focusing coincidence spectrometer. The primary function of the spectrometer is that of determining whether or not two different radiations from a radioactive sample are in the same branch of the nuclear decay scheme. Although the instrument is designed primarily for studies between conversion electron groups, it is also suitable for studies between conversion groups and beta‐spectra.
A feature of the instrument is its extraordinarily good coincidence resolving power. Applications of the spectrometer to two activities are briefly discussed, and an explanation of the high resolving power is given.

A High—Low Temperature Microscope Stage

R. E. Cech

Rev. Sci. Instrum. 21, 747 (1950); http://dx.doi.org/10.1063/1.1745702 (3 pages) | Cited 9 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
A microscope stage has been designed and constructed which permits microscopic observation of metal specimens from the temperature of liquid nitrogen to an upper temperature usually determined by the melting point of the specimen.
The stage consists of a vacuum‐tight water or liquid nitrogen‐cooled copper chamber in which a specimen is heated by passage of an electric current. A quartz window in the chamber permits ``at temperature'' observation of the specimen. Operation of this stage is described.

Random Coincidence Rates with Unsteady Sources

R. M. Littauer

Rev. Sci. Instrum. 21, 750 (1950); http://dx.doi.org/10.1063/1.1745703 (3 pages) | Cited 4 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
The random coincidence rate between two sets of pulses can be measured by delaying one of the sets through a time greater than twice the resolving time of the coincidence detector, thus destroying all true coincidences. A circuit using this principle for supervising the random rate continuously is described.

Absolute Determination of the Emission Rate of Beta‐Rays

R. K. Clark

Rev. Sci. Instrum. 21, 753 (1950); http://dx.doi.org/10.1063/1.1745704 (7 pages)

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
A technique for the absolute determination of the rate of disintegration of beta‐particle emitters is described. The method consists of measuring the rate at which charge is carried away from the active material by the emitted electrons. The effects of ionization are eliminated by placing the material in a high vacuum. The effects of the surroundings (excluding the parts required to support the active material) are reduced by using a tank of large dimensions, and the magnitude of these effects is determined by the use of supplementary surrounding surfaces with various potentials applied to them. Some information is obtained about the effects of the source supporting structures by placing over the active side of the source supporting foil a cover foil identical to it. It is shown that this technique makes possible the measurement of beta‐ray activities with high accuracy.

Electronic Pile Simulator

P. R. Bell and H. A. Straus

Rev. Sci. Instrum. 21, 760 (1950); http://dx.doi.org/10.1063/1.1745705 (4 pages) | Cited 4 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
A device has been made that follows the same set of kinetic equations as a chain‐reacting pile. The voltage output varies as a function of time as the neutron flux would vary in a pile. A potentiometer varies the effective multiplication factor and can be considered as a control rod. Five delayed neutron periods are simulated. A high precision electronic integrator is used, and the instrument is capable of an accuracy much better than one percent.
back to top
RSS Feeds

An Infra‐Red Microspectrometer for Biological Research

Darwin L. Wood

Rev. Sci. Instrum. 21, 764 (1950); http://dx.doi.org/10.1063/1.1745706 (3 pages) | Cited 3 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
The apparatus herein described consists of a totally reflecting microscope of numerical aperture 0.6 coupled with a Perkin‐Elmer Model 12C infra‐red prism spectrometer. The combination makes possible the recording of infra‐red spectra of individual cells of biological materials over the familiar range from 1 to 15μ, and has been particularly designed for the study of muscle fibers. The techniques for producing aspheric optics used in the microscope are discussed. Some preliminary performance data are given.

Modification of the Apparatus Used for the Baldes Thermoelectric Method of Measuring Osmotic Pressure

V. Everett Kinsey

Rev. Sci. Instrum. 21, 767 (1950); http://dx.doi.org/10.1063/1.1745707 (2 pages) | Cited 1 time

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Show Abstract
The apparatus employed with the Baldes method for determining osmotic pressure has been modified by substituting a breaker‐type d.c.‐a.c. amplifier for a sensitive galvanometer, thereby permitting its use under conditions where galvanometers are impractical. Precise temperature control of the water bath in which the thermoelements are immersed has been shown to be unnecessary provided the bath is stirred vigorously. A switch made from one block of electrolytically pure copper provides a satisfactory current‐reversing mechanism with low interfering contact potentials arising from non‐thermostated portions of the circuit.
back to top Laboratory and Shop Notes

The Temperature Coefficient of Resistance of Tin Oxide‐Coated Electrically Conducting Glass between 1° and 300°K

D. N. Lyon and T. H. Geballe

Rev. Sci. Instrum. 21, 769 (1950); http://dx.doi.org/10.1063/1.1745708 (2 pages) | Cited 3 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Abstract Unavailable

Improving Differential Amplifier Rejection Ratios

Richard McFee

Rev. Sci. Instrum. 21, 770 (1950); http://dx.doi.org/10.1063/1.1745709 (2 pages) | Cited 1 time

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Abstract Unavailable

Voltage Stabilizer for 200 Kv Acceleration

J. T. Dewan

Rev. Sci. Instrum. 21, 771 (1950); http://dx.doi.org/10.1063/1.1745710 (2 pages) | Cited 2 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Abstract Unavailable

A Mass Indicator

V. J. Caldecourt

Rev. Sci. Instrum. 21, 772 (1950); http://dx.doi.org/10.1063/1.1745711 (1 page) | Cited 4 times

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Abstract Unavailable

Packless Valve Flow Regulator

Walter Rose

Rev. Sci. Instrum. 21, 772 (1950); http://dx.doi.org/10.1063/1.1745712 (2 pages)

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Abstract Unavailable
back to top New Instruments

New Instruments

W. A. Wildhack

Rev. Sci. Instrum. 21, 773 (1950); http://dx.doi.org/10.1063/1.1745713 (5 pages)

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Abstract Unavailable
back to top New Materials

New Materials

Forest K. Harris

Rev. Sci. Instrum. 21, 777 (1950); http://dx.doi.org/10.1063/1.1745714 (2 pages)

Online Publication Date: 20 December 2004

Full Text: | Download PDF

Abstract Unavailable
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close