Physics Commons^™

Angular Distributions Of Conversion Electrons From Oriented Ce137M Nuclei, Richard B. Frankel, D. A. Shirley, N. J. Stone

Physics

The angular distributions of K- and of (L+M)-conversion electrons from oriented Ce^137m nuclei were observed. Precise simultaneous intensity measurements of conversion electrons and γ rays from the same sample provided an accurate, direct determination of the particle parameters b₂ associated with the 255-keV isomeric transition in Ce¹³⁷. The K-electron result, b₂=1.061 (18), is in excellent agreement with a theoretical prediction based on a "point nucleus" model. Techniques and parameters in this experiment, the first of its kind, are discussed. A more careful determination of the temperature dependence of …

Observation Of Autoionization Levels In He By Positive Ion Bombardment, M. Eugene Rudd

M. Eugene Rudd Publications

Certain highly excited energy levels in helium have been observed optically and by inelastic electron scattering, and have been calculated theoretically. Reported here is the observation of these levels by the measurement of the energy spectrum of electrons emitted after bombardment with protons and hydrogen molecular ions. Some of the states show up clearly by this method which are weak or absent in the other techniques. Berry has previously observed autoionization of helium by this method, but his measurements lacked the resolution necessary to identify the states.

Investigations Of Neutron Collimators And Detector Systems Used In A Neutron-Capture Internal-Conversion Apparatus, William Charles Johnston

Masters Theses

Preface

During the past six decades considerable effort has been devoted to investigating and explaining the phenomena associated with the atomic nucleus. However, many important features of the nucleus still are not understood. Among these are such fundamental aspects as the structural composition of the nucleus, the nature of the forces between nucleons, and several of the basic processes that occur among the nuclear constituents. The goal of nuclear physics is to construct a unified theory which is able to explain all nuclear phenomena.

The experimentalist contributes toward this objective by gathering and classifying extensive amounts of experimental data in …

The Atmospheric Neutron Spectrum At High Altitudes, Michael Sydor

Physics & Astronomy ETDs

A measurement of neutron flux in the range 30 -130 Mev at altitudes of 10, 670 feet and 100,000 feet was performed with a directionally sensitive proton recoil detector. The detector consisted of two counters of scintillator plastic which measured dE/dx and energy of proton recoils originating in a third plastic scintillator. Charged particles were eliminated by a guard counter. Energy calibration was performed with charged cosmic ray particles; efficiency and angular sensitivity were calculated. The angular response was checked at 10,670 feet, where a reasonable angular distribution of cosmic ray neutrons could be assumed.

Four balloon flights to 100,000 …

Phase-Space Occupation Of Electron, Proton, And Photon Beams, Robert Katz, Basil Curnutte Jr.

Robert Katz Publications

The intensities of known electron, proton, and photon beams are compared to the intensity of a saturated beam of fermions, providing direct experimental evidence for the boson nature of photons.

A Ti-Hg Collision Cross Section, Edward E. Stepp, Richard A. Anderson

Physics Faculty Research & Creative Works

The lifetime of the 6³P₁ state of Hg was observed as a function of Tl density at two different Hg pressures. From these data it appears that at high Tl densities the lifetime of the 6³P₁ state of Hg is controlled by collisions with Tl atoms. Using this assumption and simple gas kinetic theory, a cross section for these collisions was calculated.

Angular Correlation Of Co60, Henry Kuhlman

Masters Theses

Chapter I

Introduction

The probability that a radioactive nucleus will emit a gama ray may depend on the angle between the nuclear spin axis and the direction of emission. The radiation pattern of a sample of randomly oriented nuclei is isotropic. An anisotropic pattern may be observed if the nuclear spin axes are aligned.

A Measurement Of The Spin Relaxation Time Of Optically Pumped Rubidium Vapor, Robert Oliver Breault

Masters Theses

Chapter I

The Problem and Atomic Energy Levels

In 1949 Francis Bitter proposed a method for optcally detecting radio frequency resonance. That same year Alfred Kastler, Fcole Normale Superiéure, Paris, France, introduced a technique, which he called "Optical Pumping", of concentrating atoms in some of the Zeeman sublevels of one of the hyperfine state levels of the ground state. These two experiments are the basis of research involving optical methods of atomic orientation and of magnetic resonance.

Force-On-The-Wall Calculations For One-Dimensional Dense Gases With Intermolecular Potentials., Thomas Daniel Butler

Physics & Astronomy ETDs

The theoretical study of dense gases with strong intermolecular forces is impeded by lack of sufficient experimental which to compare predictions of the properties. High speed computers can supply this information by calculating the detailed dynamics of molecular assemblages, thereby taking the place of an actual physical experiment. This information supplied by the computers not only can test the validity of existing theories, but also it can indicate directions for possible im­provement in the theoretical approximations.

In order to show the adaptability of computers to this task, this thesis deals with the theoretical and computer-experimental study of the force exerted …

The Diffraction Of Polarized Light By A Conducting Straight Edge In The Geometrical Shadow, Richard W. Morris

Physics & Astronomy ETDs

Theory predicts that the diffraction pattern of a conduction straight edge will show deviations from the diffraction pattern of a non-conductor, and further, that these deviations will depend upon the polarization of the incident light. In this experiment the diffraction of polarized, coherent light from a monochromatic source by a metallic straight edge was studied in a region near the edge of the geometrical shadow. Two orientations of the polarization were used: one with the E vector of the polarized light parallel to the diffracting edge, and the other with the E vector perpendicular to the diffracting edge. Three different …

Determination Of The Orientation Of Air-Borne Instrumentation, David G. Miller

Physics & Astronomy ETDs

Air-borne devices have been used as a means of observation and collection of information in meteorology and atmospheric physics for many years. Only in recent years, however, has the increasing use of such devices been made for astronomical observations. A balloon-borne telescope at 80,000 to 100,000 feet, for example, has many advantages: the distortion, absorption and scattering of light by the atmosphere and the dependence on weather conditions, which plagues earthbound observations, are essentially eliminated. It seems apparent that astronomical observation will eventually be able to be made only by air­borne or satellite observatories. The decline in usefulness of the …

Single Crystals Of "Globular Molecules" From The Melt, Charles A. Aeby

Physics & Astronomy ETDs

This thesis is an investigation of the possibility of growing single crystals of dl-camphene, d-camphor, and cyclohexanol. These are organic compounds, characterized by "globular molecules", which form plastic crystals immediately below their melting point. Single crystals were desired in order to study, by ultra-sound techniques, properties pertinent to the evaluation of the elastic constants of these crystals. Primary emphasis was placed on growing crystals of dl-camphene, since it is conveniently handled at room temperatures.

Methods of growth from the melt were chosen because of the relatively fast growth rates, compared to vapor or solution techniques. Secondary considerations were simplicity of …

Large Angle Scattering Of Polarized Light By A Straight Edge, Theodore S. Fahlen

Physics & Astronomy ETDs

The purpose of this experiment was to observe the light diffracted into the geometrical shadow of a sharp and a blunt metallic straight edge using a polarized, very intense, highly coherent light source. The light source used was a ruby laser, and a Nicol prism was used to linearly polarize the laser light. Two polarizations of the laser beam were used: One with the E vector of the incident beam oriented parallel to the edge of the straight edge, and the other with the E vector oriented perpendicular to the edge. One photomultiplier tube was used to monitor the pulsed …

Phase Changes In Solid Cyclohexanol, William T. Griffith

Physics & Astronomy ETDs

Cyclohexanol is one of a group of organic compounds which exist in a “plastic crystal" solid phase, which is intermediate in its properties between the liquid phase and the solid phases stable at lower temperatures. It has been well established that the odd properties of the plastic crystal phase are due to the relatively unhindered rotation of the molecules about their lattice positions. At temperatures often considerably below the freezing point, these compounds undergo a solid-solid phase transformation in which this rotational freedom is lost. The heats and entropies of transformation at this lower transition point are generally larger than …

Deflection Of An Electron Beam By Photons, Danning W. Bloom '64

Honors Projects

The purpose of this paper was to review information, both experimental and theoretical, concerning the momentum carried by light and its effect on free electrons.

On The Calculation Of Multicenter Two-Electron Repulsion Integrals Involving Slater Functions, Russell A. Bonham, Jerry Peacher, Henry L. Cox

Physics Faculty Research & Creative Works

Integral transforms are used to evaluate many-center two-electron repulsion integrals involving Slater s-type functions. The reduction of a general four-center integral of this type to a form convenient for computational purposes is presented. The technique described has the important advantage that all lesser many-center and one-center integrals can be obtained from the four-center case by proper choice of constants. The form of the result is such that simple single-precision numerical techniques yield rapid and accurate evaluations of many-center integrals. Several numerical examples are presented.

The Effect Of Cesium Vapor On The Emission Characteristics Of Uranium Carbide At Elevated Pressures, Philip W. Kidd

Physics & Astronomy ETDs

The saturated emission current from uranium carbide in the presence of cesium vapor were measured for four different bath temperatures: 167˚C, 197˚C, 227˚C, and 250˚C (the cesium arrival rates μ_a, in atoms/cm², were 3x10¹⁸, 1x10¹⁹, 3x10¹⁹ and 6x10¹⁹). The measurements were made with a “plasma anode” type tube immersed in a constant temperature oil bath. The design of the tube is shown, and the electronic circuitry is given with an explanation of the method of measurement. The experimental data for “electron emission vs 1000/T” was plotted for the experimental …

Resonant Absorption Studies With Eu151, D. A. Shirley, Richard B. Frankel, H. H. Wickman

Physics

No abstract provided.

An Introduction To The Special Theory Of Relativity, Robert Katz

Robert Katz Publications

It is the purpose of this book to provide an introduction to the Special Theory of Relativity which is accessible to any student who has had an introduction to general physics and some slight acquaintance with the calculus. Much of the material is at a level suitable for high school students who have had advanced placement in physics and mathematics. Since some of the exposition, particularly part of Chapter 6, is presented here in book form for the first time, even terminal graduate students in physics may find the material profitable.

The Galilean Transformation
The Inertial Frame, 9; The Galilean …

Self Diffusion In Sodium Single Crystals, Aiyawar Rama Murthy

Master's Theses

The diffusion coefficients of sodium tracers in single crystals of pure sodium were measured as a function of temperature over a range of 20-41^oC. The relation D=D_o exp (-Q/RT) was found with Q 11,000 +/- 170 cal/mole and D_o 0.313 +/- 0.018 cm²/sec. These values may be compared with Q=10,450 cal/mole and D_o=0.242 cm²/sec. reported for polycrystalline sodium.

A New Determination Of The Homogeneous Nucleation Rate Of Water In Helium, Edward Francis Allard

Doctoral Dissertations

"The object of this investigation is to apply the best known cloud chamber techniques to the study of condensation phenomena, directed mainly toward the development of a precise method for the determination of homogeneous nucleation rates. A secondary object is to investigate the properties of re-evaporation nuclei so that adequate precautions may be taken to eliminate their detrimental effect in the homogeneous nucleation experiments"--Statement of Problem, page 10.

Hemispherical Spectral Emittance Of Ablation Chars, Carbon, And Zirconia To 3,700 Degrees K, Robert Gale Wilson

Dissertations, Theses, and Masters Projects

No abstract provided.

The Omegatron In Ultra High Vacuum Partial Pressure Analysis, James Mclure Bradford

Dissertations, Theses, and Masters Projects

No abstract provided.

Construction And Test Of Equipment For Use In Ultrasonic Pulse Echo Studies., Charles Joseph Reinheimer

Masters Theses

"An ultrasonic pulse generator was constructed with a variable pulse width ranging from 4 microseconds to 10 milliseconds and a repetition period varying from 15 milliseconds to 5 seconds. The oscillator had an almost continuous range from 500 kilocycles to 18 megacycles per second.

Its applicability in studies of internal friction of metals was demonstrated with a single crystal aluminum sample"-- Abstract, p. vi

A Study Of The Effect Of The Crystal Orientation On The Internal Friction Of Magnesium Single Crystals., Robert Ray Nothdurft

Masters Theses

"The method of growing, etching, and cutting magnesium single crystals is described in some detail. Ten single crystals of magnesium of different orientations were prepared and studied. The internal friction and relative Young’s modulus were measured for each specimen as a function of applied stress on a quartz composite oscillator. The effect of the orientation on the strain amplitude independent decrement, the strain amplitude dependent decrement and the ratio of the strain amplitude dependent decrement to the relative Young's modulus is compared to the theory of the pinned dislocation model of Granato and Lücke"--Abstract, p. ii

On The Kirkwood Superposition Approximation, Russell V. Cochran Jr.

Doctoral Dissertations

"When the Kirkwood superposition approximation for the triplet distribution function is used in the Born-Green equation for the pair distribution function of a liquid, the fourth virial coefficient is given incorrectly. In view of this, two suggestions for improving the approximation have been investigated. A suggestion, due to G.H.A. Cole, that better results could be obtained by using a second-order integro-differential equation of the Born-Green type with the superposition approximation used for both the triplet and quadruplet distribution functions has been investigated, and results for a hard-sphere model show that this method gives considerably less reliable results than those obtained …

Floating Potential Curves, Charles Frederick Bender

University of the Pacific Theses and Dissertations

A new method for molecular calculations was applied to the hydrogen molecule ion. Energies were calculated at different internuclear separations and simple energy differences were found. The method used was an approximate one which included two basic approximations: the use of Gaussian wave functions and the one-center method. The one-center method gives a good approximation for the electronic energies but does not give near-atomic electron densities. The title "Floating Potential Curves" comes from the fact that the Gaussian wave functions give good potential curves over a restricted region, but these curves are not oriented correctly with respect to the minimum …

The Dielectric Properties Of Thallium Nitrate., Gene E. Gowins

Masters Theses

"The purpose of this research was to investigate the dielectric behavior of thallous nitrate and to determine whether it belongs to space group Pbnm or to Pbn2.

The growing of single crystals of thallous nitrate which are suitable for dielectric measurements is difficult because the crystals are prone to initiate a dendritic growth habit. In the present work single crystals of thallous nitrate were obtained, however, by slow evaporation of an aqueous solution at 55 degrees centigrade. The crystals were plates, not larger than 8 x 8 x 2 mm, whose principal faces were subsequently indentifled as (001) planes. The …

Aging Of The Dielectric Properties Of Some Perovskite Ceramics, Hector Troche-Maldonado

Masters Theses

"The effect of aging upon the dielectric constant and the dissipation factor were investigated for a number of lead titanate zirconate ceramics of varying composition. The ceramics investigated have a perovskite type structure. The materials chosen all have tetragonal symmetry at room temperature but are close in composition to materials of rhombohedral symmetry.

Empirical relations were determined for each specimen giving the rate of aging of the dielectric constant (K) and loss factor in terms of the frequency (f) and the elapsed time (t). The range of frequency was l kcps to l mcps; the range of elapsed time was …

An Investigation Of The Sensitized Fluorescence Of The Mercury-Sodium And The Cesium-Rubidium Systems., Joseph Edward Hueser

Masters Theses

"The experimental apparatus and techniques used for the study of sensitized fluorescence are discussed. In this study both glass and metal absorption cells were employed. Included also is a discussion of the transitions which 11 occur in the mercury-sodium and the cesium-rubidium systems, which were the two systems investigated. Both photographic and photometric techniques were used as means of detecting the sensitized fluorescence. The actual experimental apparatus used are discussed together with conclusions to be drawn and recommendations to be made from the individual experiments. The purpose of the experiments was to better understand the energy exchange processes in a …