Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 47

Full-Text Articles in Physics

Measurement Of Magnetic Field Gradients By The Hall Effect, Robert D. Redin, G. C. Danielson Dec 1955

Measurement Of Magnetic Field Gradients By The Hall Effect, Robert D. Redin, G. C. Danielson

Ames Laboratory ISC Technical Reports

A magnetic field gradient measuring device, which uses the Hall effect in germanium, has been constructed. The field sensitive element is a bar of germanium 1 mm by 1 mm by 12 mm with two sets of Hall leads attached 2 mm either side of its center. One hundred cycle alternating current flows in the long direction of the bar. In a magnetic field two 100 cycle Hall voltages are obtained. These voltages, which are proportional to the magnetic field strength at two points of the field 4 mm apart, are subtracted to give an output directly proportional to the ...


The Stress-Strain Characteristics Of Uranium, David A. Mccutchan, Glenn Murphy Dec 1955

The Stress-Strain Characteristics Of Uranium, David A. Mccutchan, Glenn Murphy

Ames Laboratory ISC Technical Reports

Tests were made in reversed loading and in repeated tensile loading on thirteen specimens of rolled, alpha-uranium at room temperature. Constant strain rates ranging from 0.0003 in./in./min. to 0.0060 in./in./min. were employed.


Temperature Coefficient Of Electrical Conductivity In The System Potassium Chloride - Zinc Chloride, R. A. Fleming, R. R. Duke Dec 1955

Temperature Coefficient Of Electrical Conductivity In The System Potassium Chloride - Zinc Chloride, R. A. Fleming, R. R. Duke

Ames Laboratory ISC Technical Reports

The phase diagram of the system KCl-ZnCl2 has been constructed. Values of specific conductivity and density have been determined at eight temperatures in the range 475-650°C. for a series of compositions covering the concentration range. From these data, equivalent conductivities were calculated. The temperature coefficient of conductivity as expressed by the activation energy of ionic migration was calculated at four temperatures for each mixture.


A Possible Method For Beam Extraction From An Alternating Gradient Synchrotron, Loren R. Mcmurray, Daniel J. Zaffarano Nov 1955

A Possible Method For Beam Extraction From An Alternating Gradient Synchrotron, Loren R. Mcmurray, Daniel J. Zaffarano

Ames Laboratory ISC Technical Reports

A mathematical analysis of the effects of perturbations upon the guide field of a circular alternating gradient synchrotron was made to determine the amount and type of perturbation which would make the horizontal motion unstable, but would not affect the vertical motion to the extent that it would become unstable. The purpose of the analysis was to determine if the technique of beam extraction developed by Hammer and Bureau for a conventional synchrotron would apply to an alternating gradient synchrotron.


Multi-Band Electrical Conduction, John Browning Gibson, Joseph M. Keller Aug 1955

Multi-Band Electrical Conduction, John Browning Gibson, Joseph M. Keller

Ames Laboratory ISC Technical Reports

Scattering amplitudes arising from lattice vibrations are calculated for electrons in a transition metal, with special reference to nickel. The potential in the crystal is treated as a deformable potential, with corrections to adjust the zero of potential and to include effects of the redistribution of charge during lattice vibration.


Comparative Yields Of Fe54(Γ, Pn)Mn52 And Fe54(Γ, 2n)Fe52, Raymond M. Henry, Don S. Martin Aug 1955

Comparative Yields Of Fe54(Γ, Pn)Mn52 And Fe54(Γ, 2n)Fe52, Raymond M. Henry, Don S. Martin

Ames Laboratory ISC Technical Reports

The relative rates of formation of four photonuclear reactions produced by 70 Mev X-ray irradiations of iron metal were measured. The reactions investigated were the Fe54( γ,pn)Mn52m, Fe54(γ,pn)Mn52, Fe54(γ,2n)Fe52 and Fe57(γ,p)Mn56. The manganese yields were determined by measuring the radioactive manganese chemically separated from the target material. It was found that the total (γ,pn) yield was about 19 times greater than the (γ,2n) yield. This result is explained in terms of the lmver threshold energy of the (γ,pn ...


Electrical Properties Of Magnesium Silicide And Magnesium Germanide, Charles R. Whitsett, G. C. Danielson Jul 1955

Electrical Properties Of Magnesium Silicide And Magnesium Germanide, Charles R. Whitsett, G. C. Danielson

Ames Laboratory ISC Technical Reports

Single crystals of Mg2Si and Mg2Ge, of high purity, on the order of 1 mm x 1 mm x 1 em in size were obtained, and measurements were made of their electrical resistivities and Hall coefficients in the temperature range 60°K- 1000°K. Both compounds behaved typically as excess impurity semiconductors and exhibited apparent intrinsic conduction above 450°K.


Measurement Of The Ionization Yield Of Low Energy Atomic Particles In Gases, Ralph Lowry, Glenn H. Miller Jun 1955

Measurement Of The Ionization Yield Of Low Energy Atomic Particles In Gases, Ralph Lowry, Glenn H. Miller

Ames Laboratory ISC Technical Reports

The purpose of this investigation was to study the total ionization yield of charged atomic particles in gases for energies in the range of a few to 250 kev. A large cylindrical ionization chamber was used for this study. The charged particles were selected from the kevatron beam by a magnetic and an electrostatic analyzer and entered the chamber by means of a 0.004 inch diameter open window. A differential pumping system permitted pressures up to 10 mm Hg to be maintained in the chamber. The chamber was alternately operated as a proportional counter and an ionization chamber to ...


Secondary Electron Emission Due To Positive Ion Bombardment, John W. Murdock, Glenn H. Miller Jun 1955

Secondary Electron Emission Due To Positive Ion Bombardment, John W. Murdock, Glenn H. Miller

Ames Laboratory ISC Technical Reports

Stray electrons were produced in the Ames Laboratory linear accelerator by the ion beam striking the target and various other parts of the accelerator. This experiment was done to determine if the stray electrons from parts of the accelerator other than the target could be reduced by using construction materials other than brass. Measurements of the number of electrons produced from several materials, however, indicated that there is no particular advantage in using other materials in place of brass.


Beta Spectra Of Some Short-Lived Nuclides, Laurence S. Ring Jr., D. J. Zaffarano Jun 1955

Beta Spectra Of Some Short-Lived Nuclides, Laurence S. Ring Jr., D. J. Zaffarano

Ames Laboratory ISC Technical Reports

The determination of the energy endpoints of the beta radiation spectra from the parent nuclides of 'mirror' pairs was undertaken utilizing an improved scintillation spectrometer as the means of detection. The Iowa State College 67 Mev synchrotron was used to create the short-lived parent nuclei, and a short pneumatic tube was used to transport the samples rapidly to the counting position.


Determination Of The Angular Spread Of The X-Ray Beam From The I. S. C. (70-Mev) Synchrotron, Guveren M. Anderson, D. J. Zaffarano Mar 1955

Determination Of The Angular Spread Of The X-Ray Beam From The I. S. C. (70-Mev) Synchrotron, Guveren M. Anderson, D. J. Zaffarano

Ames Laboratory ISC Technical Reports

The radioactivity produced in copper and carbon strips by irradiation with 66 Mev bremmstrahlung is used to determine the angular spread of the X-ray beam. The beam breadth at half maximum intensity indicated an angular spread of 2.03 +/- 0.03 degrees with copper, and a spread of 2.08 +/- 0.04 degrees with carbon detectors. These results are approximately eight per cent smaller than predicted by Schiff's theory for a target of tungsten, 5 mils thick.


Ratio Of Solid Velocity To Mixture Velocity In Slurry Flow, Richard J. Burian, Glenn Murphy Mar 1955

Ratio Of Solid Velocity To Mixture Velocity In Slurry Flow, Richard J. Burian, Glenn Murphy

Ames Laboratory ISC Technical Reports

The study consisted of two parts, a theoretical analysis of the problem and an experimental investigation under controlled conditions. The theoretical analysis resulted in an equation which expressed the velocity ratio in terms of dimensionless parameters representing the distribution of the particles in the mixture, the slip between the solid particles and the adjacent fluid, and the velocity distribution of the fluid in the conduit.


Preparation, Properties, And Analytical Applications Of Some Substituted Alicyclic Vic-Dioximes, Donald Thomas Hooker, Charles V. Banks Mar 1955

Preparation, Properties, And Analytical Applications Of Some Substituted Alicyclic Vic-Dioximes, Donald Thomas Hooker, Charles V. Banks

Ames Laboratory ISC Technical Reports

The application of organic analytical reagents to the determination of metallic ions has progressed rapidly in the last few decades. Many of these organic compounds have proved to be selective in their action and thereby make possible the determination of one or two ions in the presence of several others.


High Specific Radioactivities Of Osmium From Photonuclear Reactions, R. F. Mitchell, D. S. Martin Jan 1955

High Specific Radioactivities Of Osmium From Photonuclear Reactions, R. F. Mitchell, D. S. Martin

Ames Laboratory ISC Technical Reports

The investigation described in this thesis has included a study of the activities in iridium, osmium, and rhenium which were produced by photonuclear reactions in osmium and iridium. Osmium activities produced by slow neutron bombardment on osmium metal have also been investigated. During the course of these experiments a method of concentrating osmium activities by the Szilard-Chaimers process was discovered and was further developed.


Decay Schemes Of Cl-34 And Sc-47, R. T. Nichols, E. N. Jensen Dec 1954

Decay Schemes Of Cl-34 And Sc-47, R. T. Nichols, E. N. Jensen

Ames Laboratory ISC Technical Reports

Cl34 was obtained from a gamma reaction upon ordinary chlorine and its radiation to determine the decay scheme. Three positron components were separated from the beta spectrum of Cl34 obtained from an intermediate-image spectrometer. Coincidence beta spectra obtained with the use of the same instrument gave additional energy determinations for the two lower-energy beta groups as well as indicating the time relationships between the beta groups as well as indicating the time relationships between the beta ray and the gamma rays in Cl34. The low energy gamma ray in Cl34 was studied by means of its ...


Assignment Of Transition Multipole Orders From L Subshell Internal Conversion Coefficient Ratios, Harry F. Frissel, E. N. Jensen Dec 1954

Assignment Of Transition Multipole Orders From L Subshell Internal Conversion Coefficient Ratios, Harry F. Frissel, E. N. Jensen

Ames Laboratory ISC Technical Reports

Internal conversion coefficients, hereafter symbolized by ICCs, play an important role in the field .of nuclear physics. To date physicists are unable to describe adequately the structure of the nucleus. One of the tools being used to determine nuclear structure is that of internal conversion coefficients.


Decay Characteristics Of Some Short-Lived Nuclides Of Low Atomic Number, Raymond Milton Kline, D. J. Zaffarano Jul 1954

Decay Characteristics Of Some Short-Lived Nuclides Of Low Atomic Number, Raymond Milton Kline, D. J. Zaffarano

Ames Laboratory ISC Technical Reports

The short-lived activities in Cl-34, K38, Ca-39, Li-8, He-6, and O-15 formed by high energy bremmstrahlung irradiation have been examined, and some improved values for the half-lives of these nuclides are reported. A detailed description of the apparatus and procedure is included, together with a discussion of the weighted least mean square analysis used.


Photodisintegration Of Light Elements In Nuclear Emulsions, Raymond D. Cooper, D. J. Zaffarano Jul 1954

Photodisintegration Of Light Elements In Nuclear Emulsions, Raymond D. Cooper, D. J. Zaffarano

Ames Laboratory ISC Technical Reports

The cross-sections for the reactions C-12 (gamma, 3 alpha) and O-16 (gamma, 4 alpha) have been measured as a function of photon energy from threshold to 50 Mev, and agreement with known levels is good in the former case. New levels are observed in the region 23 to 30 Mev for the latter reaction. The cross section for the reaction N-14 (gamma, 2 alpha) is observed to peak at 25 Mev, with a long tail to 45 Mev. The reaction N-14 (gamma, np)3 alpha occurs at least four times as often as the reaction N-14 (gamma, d)3 alpha.


Variations Of Electrophotoluminescence Phenomena With Frequency Of Applied Field, Keith William Olson, G. C. Danielson Jun 1954

Variations Of Electrophotoluminescence Phenomena With Frequency Of Applied Field, Keith William Olson, G. C. Danielson

Ames Laboratory ISC Technical Reports

Luminescence is a general term which includes the many phenomena involving the absorption of energy by a substance and its re=emission as visible or near visible radiation. Photoluminescence implies excitation 7 by irradiation with electromagnetic radiation; cathodoluminescence implies excitation by electron bombardment; thermoluminescence or "glow" refers to additional excitation by heat of a phosphor previously irradiated at a low temperature; and electroluminescence implies excitation by an electric field. The most recently observed phenomena, and the subjects of this investigation are those included in the general term "electrophotoluminescence" which refers to the effect of an electric field on photoluminescence. Luminescence ...


The Tensile Properties Of Uranium In The Inelastic Range Of Stress, Robert Wells Lewis, Glenn Murphy Jun 1954

The Tensile Properties Of Uranium In The Inelastic Range Of Stress, Robert Wells Lewis, Glenn Murphy

Ames Laboratory ISC Technical Reports

Tensile tests were made on specimens of uranium at strain rates varying from 0.0003 min^-1 to 0.003 min^-1 and at temperatures from 25°C to 300°C to study the effect of these variables on the strain hardening of the metal. At room temperatures an increase tn yield strength of 100 per cent may be induced by a prior loading into the plastic range. Within the limits studied the effect of rate of strain upon strain hardening is negligible. Other factors being equal, the potential strain hardening decreases with an increase in temperature. The data are ...


Radioactive Disintegration Spectra Of Some Short-Lived Nuclides, Warren A. Hunt, D. J. Zaffarano Mar 1954

Radioactive Disintegration Spectra Of Some Short-Lived Nuclides, Warren A. Hunt, D. J. Zaffarano

Ames Laboratory ISC Technical Reports

The beta endpoint energies of several short=lived, low Z radioactive nuclides have been measured with an improved scintillation spectrometer. These values have been combined with recent half-life determinations to give the ft values.


Radiations From Cerium-141, James Jones Jr., Erling Jensen Jan 1954

Radiations From Cerium-141, James Jones Jr., Erling Jensen

Ames Laboratory ISC Technical Reports

Information obtained by examining radiations emitted from radioactive isotopes is of value in checking various nuclear theories. In this work, the radiations from ,Ce have been investigated; a tentative decay scheme is indicated which gives an assignment of energy levels, sequence of emission, total angular momentum, and parity.


The Half-Lives Of Some Short Lived Low Z Nuclei Formed By Photonuclear Reactions, Philip Phipps, D. J. Zaffarano Dec 1953

The Half-Lives Of Some Short Lived Low Z Nuclei Formed By Photonuclear Reactions, Philip Phipps, D. J. Zaffarano

Ames Laboratory ISC Technical Reports

The half-lives of several members of the "mirror" nuclei series have been measured, using improved scintillation counter detectors and a cycling apparatus which progams the synchrotron beam and several subsequent gated detectors in sequence repetitively. By the use of beta-ray energy discrimination, least squares fitting of decay curves, and by careful correction for background activities, the improved values listed in Table A were found.


Device For Detection And Identification Of Charged Particles From Photonuclear Reactions, Albert William Snyder, D. J. Zaffarano Dec 1953

Device For Detection And Identification Of Charged Particles From Photonuclear Reactions, Albert William Snyder, D. J. Zaffarano

Ames Laboratory ISC Technical Reports

A device is described which makes possible the determination of the energy spectrum of protons, alpha particles, or deuterons in the presence of other charged particles. Energy loss per unit path length (dE/dx) and total energy (E) are displayed in the form of voltage pulses of varying amplitudes in quadrature on an oscilloscope screen. The peaks of the pulses are intensitifed, resulting in hyperbolic loci for different types of particles. By masking the oscilloscope screen and using the moving film pulse height analysis technique developed in this laboratory, independent energy spectra may be obtained for each type of particle.


Transmission Of 0-5- Kilovolt Electrons By Thin Films With Applications To Beta-Ray Spectroscopy, Raymond O. Lane, D. J. Zaffarano Dec 1953

Transmission Of 0-5- Kilovolt Electrons By Thin Films With Applications To Beta-Ray Spectroscopy, Raymond O. Lane, D. J. Zaffarano

Ames Laboratory ISC Technical Reports

The penetration of electrons through matter has long been the subject of both theoretical and experimental investigations. Because of simplicity, the investigation frequently deals with a collimated beam of monoenergetic electrons incident normally upon a planar target. Two of the most useful measurements connected with such an experiment concern the range or depth of penetration of electrons in the target, and the intensity of the transmitted beam as a function of incident energy. One object of this research is to determine experimentally range-energy data for thin films. The other object is to measure the transmission of electrons by a thin ...


Ionization Yields Of Fission Fragments In Gases, Lloyd O. Herwig, Glenn Miller Dec 1953

Ionization Yields Of Fission Fragments In Gases, Lloyd O. Herwig, Glenn Miller

Ames Laboratory ISC Technical Reports

The present problem arises from a consideration of some of the experimental and theoretical results which were obtained previously, some of which will now be briefly mentioned. Fission fragment mass distributions which were derived from data obtained from double ionization chambers using argon plus carbon dioxide gases disagree with those obtained by means of radiochemical analysis of the fission products. Fission fragment velocity distributions which were also derived from double ionization chamber data disagree with those obtained from a direct measurement of velocities. Further, these double ionization chamber measurements of the total kinetic energy of fission give lower values than ...


Temperature Distribution In A Metal Cylinder Containing A Heat Source, Leon Pletke, Glenn Murphy Aug 1953

Temperature Distribution In A Metal Cylinder Containing A Heat Source, Leon Pletke, Glenn Murphy

Ames Laboratory ISC Technical Reports

The object of this reportt is to describe a method for finding the temperature distribution in a metal cylinder containing a heat source distributed in any manner throughout the cylinder. Specific solutions are given for cylinders with L/D ratios of 1, 2, 3, and ∞.

.


Heats Of Solution And Related Thermochemical Properties Of Some Rare Earth Metals And Chlorides, James P. Flynn, F. H. Spedding Jul 1953

Heats Of Solution And Related Thermochemical Properties Of Some Rare Earth Metals And Chlorides, James P. Flynn, F. H. Spedding

Ames Laboratory ISC Technical Reports

An isothermally jacketed calorimeter has been constructed to measure the changes in heat content accompanying the solution of some rare earth metals and compounds. To check the performance of the apparatus, the integral heats of solution of potassium nitrate in water at 25°C have been measured. The values corrected to infinite dilution by use of relative apparent molal heat content data in the literature give 8384 +/- 12 cals/mole. The result agrees well with the values reported by others.


The Molten-Metal-Fuel Reactor, F. H. Spedding Jun 1953

The Molten-Metal-Fuel Reactor, F. H. Spedding

Ames Laboratory ISC Technical Reports

Scientists who were engaged in the atomic program before the end of 1943 had pretty well outlined most of the types of reactors which are being discussed today. These outlines were usually quite general and merely sketched the theoretical possibility of building a particular type of reactor. Many of these discussions were not recorded, and the records of others are hard to find today since they are buried in the Project literature and have not been properly indexed. However, a careful search of reports such as the minutes of the Project Council and the weekly and monthly reports of the ...


A Beta-Ray Spectrometer For Coincidence Measurements, R. T. Nichols, A. V. Pohm, J. H. Talboy Jr., E. N. Jensen May 1953

A Beta-Ray Spectrometer For Coincidence Measurements, R. T. Nichols, A. V. Pohm, J. H. Talboy Jr., E. N. Jensen

Ames Laboratory ISC Technical Reports

An intermediate image beta-ray spectrometer has been constructed utilizing the focusing properties of a U-shaped magnetic field distribution. The construction and performance of the instrument are discussed. A transmission of ten percent has been attained with a resolution of about six percent. A scintillation spectrometer is used in conjunction with the intermediate image spectrometer for the purpose of making coincidence measurements.