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Dec 1950

Volume 21, Issue 12, pp. 945-1033

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Beta‐Ray Spectroscopes

E. Persico and C. Geoffrion

Rev. Sci. Instrum. 21, 945 (1950); http://dx.doi.org/10.1063/1.1745497 (26 pages) | Cited 20 times

Online Publication Date: 20 December 2004

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This paper is a review of the various types of beta‐ray spectrographs and spectrometers. The principal theoretical results as to the resolving power and luminosity attainable under various conditions are briefly related. Finally the construction and performance data of a number of instruments described in the literature are collected, and compared by means of a graphical representation.

An Orbit‐Bender to Assist Injection into Betatrons

Leverett Davis

Rev. Sci. Instrum. 21, 971 (1950); http://dx.doi.org/10.1063/1.1745498 (2 pages) | Cited 1 time

Online Publication Date: 20 December 2004

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It is suggested that the fraction of the beam in a betatron or synchrotron that is lost by striking the injector might be decreased by a suitable transient bending of the steady‐state orbit during injection.

An Improved Electrical Network for Determining the Eigenvalues and Eigenvectors of a Real Symmetric Matrix

Abraham Many

Rev. Sci. Instrum. 21, 972 (1950); http://dx.doi.org/10.1063/1.1745499 (3 pages) | Cited 3 times

Online Publication Date: 20 December 2004

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An electrical computor for determining the eigenvalues and eigenvectors of real symmetric matrices up to the tenth order is described. It is an enlarged and an improved form of a computor described in a previous paper. The time required for solution is considerably reduced, and the accuracy is ten times higher. The solution of a matrix of the tenth order takes four hours, as compared to a hundred hours by computational methods. The accuracy of the eigenvalues is about 0.01 percent of the difference between the greatest and smallest eigenvalues, and the accuracy of each eigenvector is better than one percent of its greatest component.

Distributed Coincidence Circuit

Clyde Wiegand

Rev. Sci. Instrum. 21, 975 (1950); http://dx.doi.org/10.1063/1.1745500 (2 pages) | Cited 8 times

Online Publication Date: 20 December 2004

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A coincidence circuit using the traveling wave principle as applied to distributed amplification is described. The resolving time is about 10−8 sec. when the device is used in connection with scintillation detectors.

A Continuously Sensitive Cloud Chamber

T. S. Needels and C. E. Nielsen

Rev. Sci. Instrum. 21, 976 (1950); http://dx.doi.org/10.1063/1.1745501 (2 pages) | Cited 20 times

Online Publication Date: 20 December 2004

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A particularly simple cloud chamber is described that is continuously sensitive to ion tracks. The chamber operates on the principle of vapor diffusion from a hot to a cold surface. The sensitive region is a shallow horizontal layer near the cold surface. The chamber has been placed in a magnetic field and curved tracks of β‐particles from a radioactive source have been photographed. Pictures of such electron tracks are shown.

A Semi‐Automatic Device for Analyzing Events in Nuclear Emulsions

Marietta Blau, Robert Rudin, and Seymour Lindenbaum

Rev. Sci. Instrum. 21, 978 (1950); http://dx.doi.org/10.1063/1.1745502 (8 pages) | Cited 7 times

Online Publication Date: 20 December 2004

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An apparatus is described the basic element of which is a microscope with a motor‐driven stage. The operator controls the direction and speed of motion by a steering wheel and an accelerator pedal and drives the track to be analyzed through a target. Range, grain density, and geometrical orientation of tracks, etc., are automatically recorded on charts. Methods of measurements and results are discussed.

A Double Thin Lens Beta‐Ray Spectrometer

C. M. Van Atta, Sydney D. Warshaw, Joses J. L. Chen, and Samuel I. Taimuty

Rev. Sci. Instrum. 21, 985 (1950); http://dx.doi.org/10.1063/1.1745503 (6 pages) | Cited 5 times

Online Publication Date: 20 December 2004

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The description of the performance of a double thin magnetic lens beta‐ray spectrometer is given. A detailed investigation of the separate distortions introduced by chamber misalignment, internal scattering, charged source and poor resolution has been made, and the results are presented qualitatively. An alignment procedure is presented, and also the arrangement of baffles to minimize scattering.

Continuously Sensitive Diffusion Cloud Chambers

E. W. Cowan

Rev. Sci. Instrum. 21, 991 (1950); http://dx.doi.org/10.1063/1.1745504 (6 pages) | Cited 24 times

Online Publication Date: 20 December 2004

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The following types of continuously sensitive diffusion cloud chamber have been built and successfully operated: a chamber designed to be photographed through the top for use with a particle accelerator; a chamber designed to be photographed from the side for cosmic‐ray studies; and a very simple chamber for demonstration purposes. The construction and best operating conditions are described.

A Rapid Method for Calculating and Using Platinum Thermohm Tables

R. A. Buerschaper

Rev. Sci. Instrum. 21, 996 (1950); http://dx.doi.org/10.1063/1.1745505 (3 pages) | Cited 1 time

Online Publication Date: 20 December 2004

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A method is described whereby resistance‐temperature tables can be calculated in a few hours using punched cards. The method is much simpler and quicker to use than the ``platinum temperature'' tables. An example is given for reducing resistance measurements to temperature and a method for checking bridge and thermohm drift with respect to the tables is proposed.

An Electronic Recording Analytical Balance

Idas W. Lohmann

Rev. Sci. Instrum. 21, 999 (1950); http://dx.doi.org/10.1063/1.1745506 (4 pages)

Online Publication Date: 20 December 2004

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An electronic recording analytical balance is described which is free of mechanical connections with the balance beam, direct reading, sensitive, and rapid. All mechanical and electrical contactors have been eliminated from the instrument proper, using electronic means as a substitute for mechanical. A relay and two cam‐operated microswitches are, however, used in the range extender. The construction is simple, being made up, for the most part, of available standard commercial units. For work requiring a continuous record of changes in weight with respect to time, the instrument should prove to be most valuable.

A Capacitance Bridge for High Frequencies

J. S. Mendousse, P. D. Goodman, and W. G. Cady

Rev. Sci. Instrum. 21, 1002 (1950); http://dx.doi.org/10.1063/1.1745479 (8 pages)

Online Publication Date: 20 December 2004

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A type of bridge for measurements at frequencies in the megacycle range is described, containing two fixed capacitors and a variable capacitor. The unknown impedance is connected in the fourth arm as a ``load.'' The unbalanced high frequency e.m.f. is rectified by a germanium crystal rectifier and measured as a small d.c. voltage. The bridge is ``balanced'' by varying the variable capacitance until the ratio of output d.c. to input h‐f voltage is at a minimum. The impedance of the variable capacitor is then numerically equal to that of the load.
In a second and perhaps more important application, the bridge is used for examining vibrational modes and measuring the Q of piezoelectric crystals or transducers. Here the variable capacitor is set at a fixed value equal to the parallel capacitance of the crystal, and the output voltage is observed, or recorded graphically, while the frequency is slowly varied over the resonance range. Some graphical records are shown, illustrating the performance of crystals at various frequencies and under different mechanical loads.
The theory of the bridge is given, and sources of error are discussed.

Transmission Line Reflection Doubling Amplifier

John Marshall

Rev. Sci. Instrum. 21, 1010 (1950); http://dx.doi.org/10.1063/1.1745480 (4 pages)

Online Publication Date: 20 December 2004

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A pulse amplifier has been constructed using voltage doubling by reflection at the open end of a transmission line. Cathode followers are used to couple the output of one line into the input of the next. An amplifier using in each stage the four triode units of two 6J6's in parallel driving 16 feet of 100‐ohm line has theoretically a voltage gain of 1.32 per stage. With appropriate grid series compensation the gain can be made constant, theoretically, to 100 megacycles. Experimentally the gain is 1.3 per stage with a rise time less than 6×10−9 sec. Below 50 volts, distortion is not serious for pulses shorter than twice the transmission time of the line. Pulses up to 150 volts can be handled by the amplifier.

A Frequency Meter for Microwave Spectroscopy

John D. Rogers, Henry L. Cox, and Paul G. Braunschweiger

Rev. Sci. Instrum. 21, 1014 (1950); http://dx.doi.org/10.1063/1.1745481 (2 pages) | Cited 2 times

Online Publication Date: 20 December 2004

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A frequency meter using known absorption lines as microwave frequency standards has been developed. By mixing signals of unknown microwave frequency fx, standard microwave frequency f0, and known radiofrequency signals nfc from a crystal‐controlled harmonic generator, it is possible to obtain a set of ``beat'' frequencies fr which can be detected by a calibrated radio receiver. From the relation
math
it is possible to determine values for the unknown microwave frequency fx. Tests on methanol absorption lines with ammonia lines as microwave frequency standards show that microwave frequencies can be determined to ±0.03 mc/sec. Advantages of this device over other frequency meters are discussed; the accuracy is ultimately limited by the uncertainties in the value of the standard frequency f0.

Apparatus for Concentration of He3 by Thermal Diffusion

O. F. Schuette, A. Zucker, and W. W. Watson

Rev. Sci. Instrum. 21, 1016 (1950); http://dx.doi.org/10.1063/1.1745482 (3 pages) | Cited 6 times

Online Publication Date: 20 December 2004

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A multistage thermal diffusion apparatus for the concentration of He3 is described. Included is a novel three‐stage, all‐metal column based on a G. E. Calrod heater. Concentration was carried only to a He3/He4 ratio of 0.05 percent, a factor of 3.3×103. The performance indicates the importance of having the hot wall in concentric cylinder columns made of metal of good thermal conductivity to minimize azimuthal temperature gradients which can markedly increase parasitic remixing of the gas if a metal such as stainless steel is used.

Gas Flow through the Mass Spectrometer Viscous Leak

R. E. Halsted and Alfred O. Nier

Rev. Sci. Instrum. 21, 1019 (1950); http://dx.doi.org/10.1063/1.1745483 (3 pages) | Cited 12 times

Online Publication Date: 20 December 2004

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An approximate expression for the flow of a binary gas mixture through a mass spectrometer ``viscous'' leak has been derived and compared with experimental data. The factors important in the design and use of the leak are determined from this result.
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Erratum. Tektronix Advertisement

Rev. Sci. Instrum. 21, 1021 (1950); http://dx.doi.org/10.1063/1.1745484 (1 page)

Online Publication Date: 20 December 2004

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The Tektronix advertisement in the July issue, publicizing their Type 514‐D Cathode Ray Oscilloscope, erroneously listed the sweep range as being ``.01 usec/cm to .01 sec/cm.'' This should have read ``.1 usec/cm to .01 sec/cm.'' They sincerely regret any inconvenience they might have caused to any of the readers of The Review of Scientific Instruments.
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Detection of Tritiated Compounds in Paper Chromatography

Irving Gray, Saburo Ikeda, Andrew A. Benson, and David Kritchevsky

Rev. Sci. Instrum. 21, 1022 (1950); http://dx.doi.org/10.1063/1.1745485 (1 page) | Cited 2 times

Online Publication Date: 20 December 2004

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A windowless tube has been developed which can be used to detect tritium activity on paper, glass, or aluminum. The tube is of glass, with a nichrome anode and a copper sulfide coated copper cathode, and utilizes a stream of helium saturated with alcohol. This device is convenient for detection of tritiated compounds in paper chromatography.
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A Simplified Percent Transmission Computer

A. L. McClellan and G. C. Pimentel

Rev. Sci. Instrum. 21, 1023 (1950); http://dx.doi.org/10.1063/1.1745486 (1 page)

Online Publication Date: 20 December 2004

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Abstract Unavailable

Note on Crystals Suitable for Double Crystal X‐Ray Spectroscopy in the Region 3 to 15A

S. T. Stephenson and D. L. Martin

Rev. Sci. Instrum. 21, 1023 (1950); http://dx.doi.org/10.1063/1.1745487 (2 pages)

Online Publication Date: 20 December 2004

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Abstract Unavailable

A Greaseless Gas Flow Valve

R. E. Honig

Rev. Sci. Instrum. 21, 1024 (1950); http://dx.doi.org/10.1063/1.1745488 (2 pages) | Cited 1 time

Online Publication Date: 20 December 2004

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Abstract Unavailable

Zero Inefficiency Anticoincidence Circuit

M. Degallier

Rev. Sci. Instrum. 21, 1025 (1950); http://dx.doi.org/10.1063/1.1745489 (1 page)

Online Publication Date: 20 December 2004

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Abstract Unavailable

Varying Nuclear Emulsion Sensitivity with Altitude

Arthur Beiser

Rev. Sci. Instrum. 21, 1025 (1950); http://dx.doi.org/10.1063/1.1745490 (2 pages)

Online Publication Date: 20 December 2004

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Abstract Unavailable

Cathode‐Follower Fallacies

Paul I. Richards

Rev. Sci. Instrum. 21, 1026 (1950); http://dx.doi.org/10.1063/1.1745491 (1 page)

Online Publication Date: 20 December 2004

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Abstract Unavailable

Electron Optical Disk

L. Marton and J. Arol Simpson

Rev. Sci. Instrum. 21, 1027 (1950); http://dx.doi.org/10.1063/1.1745492 (2 pages)

Online Publication Date: 20 December 2004

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See Also: Erratum

Abstract Unavailable

A New Method for the Measurement of Hall Coefficients

B. R. Russell and C. Wahlig

Rev. Sci. Instrum. 21, 1028 (1950); http://dx.doi.org/10.1063/1.1745493 (2 pages) | Cited 27 times

Online Publication Date: 20 December 2004

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See Also: Erratum

Abstract Unavailable
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