Physical Sciences and Mathematics Commons^™

A Transister Quenching Circuit For Geiger Counter Tubes, Andrew M. Simko

Physics & Astronomy ETDs

This thesis attempt to provide a solution to a basic problem inherent in the operation of Geiger-Mueller counting tubes, that is, reduction of the insensitive time, or “dead time”, following the discharge. Many researchers, using various quenching gases for internal quenching and various vacuum tube circuits for external quenching, have succeeded in reducing the “dead time” significantly. Reduction of the insensitive time provides more efficient and accurate counting. The solutions presented in this thesis utilize transistor circuits instead of vacuum tube circuits for external quenching. In an extensive research of current literature, no attempts to transistorize a quenching circuit could …

A Correlation Between The Responses Of A Cherenkov Counter, And A Liquid Scintillator, To An Extensive Air Shower, John Wolcott

Physics & Astronomy ETDs

To date there have been no adequate measurements of the energy spectrum of high energy cosmic gamma-rays. This information can only be obtained from instrumentation located above the atmosphere. An experiment has been designed by Dr. Leavitt at the University of New Mexico to obtain this information. It is to be orbited in the S-17 Orbiting Solar Observatory.

Fast Neutron Induced Fission Of U238, Michael J. Bennett

Physics & Astronomy ETDs

This work describes an experimental study of the energetics of the fission of U²³⁸ performed with solid state detectors. The fissions were produced by fission-spectrum neutrons from a reactor. The procedure used for calibrating the detector response is described and the effects of some experimental uncertainties, such as pulse height defect and neutron emission, are discussed.

A Theoretical And "Experimental" Investigation Of One-Dimensional Molecular Distribution Functions, Samuel Blackman

Physics & Astronomy ETDs

The presence of long range forces and of various types of boundary conditions may be expected to cause deviations from the well known Maxwell-Boltzmann velocity distribution, resulting in a spatially dependent velocity distribution. One possible method for obtaining a theoretical spatially dependent velocity distribution is to attempt an approximate solution for Liouville's equation. This is done in this thesis. The effects of a long range repulsive force inversely proportional to the interparticle separation as well as the effects of three types of wall boundary conditions upon the velocity distributions of a one-dimensional set of ordered particles have also been investigated …

A Radio Frequency Power Oscillator And Impedance Matching Device., Charles D. Preston

Physics & Astronomy ETDs

Certain molecules, called “globular” molecules, when first solidified form what are called “plastic” crystals. They are called “globular” either because they may exhibit an approximate spherical symmetry about their center of structure or because they may be small enough or of such a shape as to appear spherically symmetric because of rotation. The first case might be exemplified by methane (CH4) which has the configuration of a regular tetrahedron. The second case might be exemplified by hydrogen chloride (HCL).

A Proposed Modification Of The Available Momentum Region In Thomas-Fermi Theory, John F. Barnes

Physics & Astronomy ETDs

The statistical model of the atom, first propounded by Fermi and Thomas has proved a most useful approximation to the self-consistent field method in calculating electron distributions and fields in atoms. Because of its relative simplicity, it has found wide application as a means of predicting properties of free atoms and of solids. The original theory has been the subject of many modifications and refinements, some of which are reviewed in this paper.

The Leakage Neutron Spectrum Of A Spherical Critical Assembly Of U233, Larry E. Bobisud

Physics & Astronomy ETDs

In this paper the spectrum of the neutrons escaping from a critical sphere of U²³³ is investigated experimentally and theoretically. The experimental investigation involved exposing a nuclear emulsion to the neutron flux and, after development, examining the details of the proton-recoil tracks visible in the emulsion.

On The Velocity Of Sound In Cubic Crystals, Stuart Fleming Hayes

Physics & Astronomy ETDs

The object of this inquiry is to examine the relation between plane wave sound velocities in cubic crystals and the elastic constants of such crystals. Leading directly into this an extensive treatment of the classical theory of elasticity as it pertains to the cubic system. An application of the results will be made by detailing a means for obtaining the elastic constants of plastic single-crystals from measurements of velocity made on poly crystalline specimens.

The Time Required For Nuclear Fission, William Earn Stein

Physics & Astronomy ETDs

The present work is concerned with the mean lifetime of compound nuclei formed in the fast-neutron-induced-fission process. A new method for the measurement of these lifetimes is proposed. The present method is based on the recoil of the compound nucleus following neutron capture and the secondary electrons emitted by fission fragments. Previous experimental and theoretical work concerning the secondary electron yields for fission fragments and other charged particles are reviewed. The importance of the higher energy electrons, the so-called delta rays, formed in the primary ionization process is considered. The subsequent secondary ionization produced by these delta rays provirles a …

The He3 + T Reactions., Darryl B. Smith

Physics & Astronomy ETDs

The energy distribution of the alpha particles and of protons frim the He3+ t reactions have been measured for 1.9-Mev incident tritons at laboratory angles of 30° for alpha, and both 30° and 90° for protons. Absolute cross selections are obtained. The spectra are discussed in terms of a model which assumes that uncorrelated three-body breakup and several two-stage processes all contribute independently to the cross section. The calculations based on this model are in excellent agreement with the observed spectral shapes. The neutron-proton correlation corresponding to the unbound singlet state of the deuteron is observed. The binding energy of …

The Energy Spectrum Of Gamma Rays Produced In Interstellar Matter By The Primary Cosmic Rays, Duquesne A. Wolf

Physics & Astronomy ETDs

With the advent of the launching of space exploration in the last decade there has been parallel scientific effort to determine the nature of cosmic radiation found in space.

This theoretical study has the objective of determining the energy spectrum of gamma rays produced in interstellar matter by the primary cosmic rays.

Multiple Scattering Of High Energy Electrons In A Cerenkov Counter, John Rehnberg

Physics & Astronomy ETDs

The purpose of this thesis is to present a procedure for calculating the fraction of high energy electrons incident on a Cerenkov counter which are scattered out of the region of detection.

With the assistance of Professor Christopher P. Leavitt of the University of New Mexico, a method of solving the above problem has been established. The method uses the theory of multiple scattering as described by Rossi and Greisen and a numerical integration technique to evaluate the effective or average scattering distribution function for the Cerenkov counter. A relationship is developed which can be programmed on a Bendix G-15 …

Calibration Of A Liquid Scintillator With Geiger-Mueller Counters, William F. Hartman

Physics & Astronomy ETDs

It was the purpose of this experiment to examine the difference in the density determinations and, since the Geiger tube threshold is much lower, to calibrate the liquid scintillator so that it is capable to determining the absolute particle density with greater accuracy.

Diffraction Of Spherical Scalar And Vector Waves At Axial Points Of A Circular Aperture And Disk, Keith Leon Mcdonald

Faculty Publications

The following work treats Kottler's saltus problem of diffraction of electromagnetic waves emitted by a Hertzian oscillator source and the analogous Kirchhoff's scalar problem of waves emitted by a point source. The medium is a homogeneous isotropic dielectric. In the vector case a new exact solution of the basic integrals is presented, at axial points only, (a) behind a circular aperture in a "black'' screen, and (b) behind its complementary "black'' disk. The relative time-averaged intensity of energy flow is plotted for the disk only. It is shown that the scalar theory predicts considerably larger values than the electromagnetic theory …

A Telemetric Compass, Paul Nelson Jr.

Physics & Astronomy ETDs

In certain types of experiments involving balloon-borne equipment it is desirable to know how the orientation of the apparatus varies with time. The author has investigated a method of telemetering azimuthal orientation from a balloon to the ground, and has constructed a protoype of a telemetering magnetic compass. The basis of the compass is a rotating-ring magnetometer of the type first described by Nielsen (1) and used by others (2,3,4) for various purposes. The output of this device consists of two a.c. signals, whose relative phase is determined by the orientation of the magnetometer with respect to the external magnetic …

Anisotropy Of The Cosmic-Ray Flux Caused By An Interplanetary Magnetic Field, Ronald R. Harrington

Physics & Astronomy ETDs

The purpose of this study is to investigate the possibility that this diurnal variation in cosmic-ray flux may be due to a general dipole-like magnetic field centered upon the sun.

A Study Of The Elastic Scattering Of 25-Mev He3 Ions From Various Nuclei, Dale D. Armstrong

Physics & Astronomy ETDs

The validity of the assumption of strong absorption as the basis for the description of the interaction of He³ ions and nuclei was not definitely established and probably cannot be established without the application of more sophisticated theories.

Origins Of Shock-Induced Luminescence In Quartz, William P. Brooks

Physics & Astronomy ETDs

Alpha quartz is a piezoelectric material. As such, it will yield voltage under stress. When shocked with high explosive systems, the material is also luminescent. This luminescence is quite intense and can be recorded on normal films at submicrosecond exposure times.

The luminescence appears in various patterns determined both by the explosive system used and by the orientation of the quartz.

Fused quartz exhibits luminescence to a lesser degree. Since fused quartz is not piezoelectric, it is helpful in the determination of the origin of the luminescence in crystalline alpha quartz.

This study of the origin of the luminescence in …

A Liquid Hydrogen Bubble Chamber Designed For Use As A Neutron Spectrometer, Edward R. Flynn

Physics & Astronomy ETDs

A liquid hydrogen bubble chamber for use as a neutron spectrometer has been constructed and operated. The chamber employs 90^o stereography and is expanded by a piston located in the liquid. The construction and operation of the chamber are described. A special measuring microscope for analyzing the data is described along with the associated electronics for digitizing the screws of this device. Reading rates of 60 proton recoils per hour have been obtained and the reading procedure is discussed. Preliminary results from a neutron-proton differential cross section measurement indicates a resolution of 5% may be obtained with 22 Mev …

A Satellite Ratemeter Circuit, Daniel P. Christman

Physics & Astronomy ETDs

It was proposed that an attempt be made to measure the directional energy of high-energy primary gamma radiations in space. The difficulties of such an effort are readily obvious. To escape the environmental air envelope of the earth and to lessen the interference of secondary radiations, an instrument package would have to placed into a known orbital trajectory.

A Telemetering Inclinometer, Robert G. Geil

Physics & Astronomy ETDs

In present day experiments in Atmospheric Physics, information from the experiment is sometimes telemetered to observers located at positions remote from the apparatus. To obtain data from the stratosphere an instrument package may be sent aloft suspended from balloons. It is often desirable to know the azimuthal orientation of the instrument package.

To achieve this purpose a rotating ring magnetometer has been developed at the University of New Mexico to measure azimuthal orientation using the earth's magnetic field for a reference. This is sufficient for many purposes. However, due to the wind currents the package suspended beneath the balloon may …

"Invariant Imbedding" And Wave Propagation In Inhomogeneous Media, Crawford J. Maccallum

Physics & Astronomy ETDs

We wish now to address ourselves to that problem which can be described in physical terms as the reflection and transmission of "waves" by and through some sort of "transition region" between two homogeneous media. At this stage we will work strictly within one dimension; later on this severe restriction will be somewhat eased. For simplicity of notation we will for the present give the transition region a finite thickness h; later on we will often allow h to become infinite when the disturbance due to the transition region dies away fast enough with distance.

A Note On K-Commutative Matrices, D. W. Robinson

Faculty Publications

Let A and B be square matrices over a field in which the minimum polynomial of A is completely reducible. It is shown that A is k commutative with respect to B for some non-negative integer k if and only if B commutes with every principal idempotent of A. The proof is brief, simplifying much of the previous study of k-commutative matrices. The result is also used to generalize some well-known theorems on finite matrix commutators that involve a complex matrix and its transposed complex conjugate.

Long-Range Particles From Nuclear Fission, Ralph A. Nobles

Physics & Astronomy ETDs

This work is concerned with experimental observations of the long-range particles which are occasionally emitted by fissioning nuclei. These particles are known to be principally alpha particles and are of interest because they are associated with the configuration of the nucleus at the crucial time of scission. Observations were made of the energy spectra of long-range particles by means of a thallium-activated multiple CsI crystal scintillator device.

A Calibration Method For Satellite Cerenkov Instrumentals, Robert E. Dekinder Jr.

Physics & Astronomy ETDs

The problem posed for this thesis is one of determining a method of calibrating a photomultiplier tube when it is contained in an orbiting instrumentation package. Since it is planned for the satellite to remain in orbit for about two years, a method to determine drift of the telemetered output versus the selected radiation input would be very desirable. This drift could arise from changes in the power supplied to the system, or by the telemetering or logic circuits changing characteristics from exposure to cosmic radiation. The situation requires that light of constant intensity be produced in the "field of …

The Wavelength Shifting Of Cerenkov Radiation, Philip A. Deutchman

Physics & Astronomy ETDs

The main interest in this paper is to study the effect of the florescent wavelength shifter "POPOP" with respect to Cerenkov radiation and to determine how the efficiency of a Cerenkov counter is affected.

Angular Distribution Of Electrons In Extensive Air Showers, Don D. Laniewski

Physics & Astronomy ETDs

Electrons are the main products of an extensive air shower and comprise approximately 90% of the shower. Since these electrons are the most numerous particles near the axis of a large shower and are not easily detected, extensive air showers are most easily studied by means of the electronic component. Thus, whatever concern there may be about the nucleonic cascade of which the electron is an outgrowth, it is necessary first to understand the development of the electronic component and is lateral and angular distribution. Also, for the correct analysis of any experimental data, it is of particular importance to …

An Analysis Of Bursting Bubbles At Liquid Surfaces, Keith James Gilbert

Physics & Astronomy ETDs

This phenomenon of the spray produced by bursting bubbles at liquid surfaces is certainly familiar to drinkers of carbonated soda pop, champagne and other effervescent liquids. This same phenomenon has been observed at ocean surfaces. Small bubbles, some of which originate at great depths, rise to the surface and break; tiny droplet is thrown upward from most of the imploding bubbles. Some of these droplets may be caught and carried into the atmosphere by winds sweeping along the surface. The droplets evaporate but leave small particles of salt suspended in the air; the particles then serve as condensation nuclei and …

Design Of An Instrument To Detect High Energy Photons At High Altitudes, Donald L. Evans

Physics & Astronomy ETDs

The purpose of this thesis is to design a high altitude instrument which will detect photons with an energy greater than 1 Bev, and which will discriminate between zenith and albedo radiation.

Absorbance Of The Oh Radical In A Specific Wavelength Interval Near 309a, Paul F. Bird

Physics & Astronomy ETDs

The absorbance of the OH radical as a function of optical density was studied by computing the absorbance for an incident radiation in the wavelength interval 3089A-3097A. The absorbance was studied for 3 different temperatures and various values of the parameters specifying the line shapes and magnitude of the spectral absorption coefficient.