Physical Sciences and Mathematics Commons^™

Application Of Shower Theory To High Energy Total Absorption Čerenkov Radiation Counter, Frederick Young

Physics & Astronomy ETDs

Theoretical calculations describing the performance of a Čerenkov counter designed as a total absorption gamma ray spectrometer for the energy range 100-1000 Msv are presented, using approximation "A" from the standard shower theory, and R. Wilson's quasi-analytical method of cascade shower analysis.

Study Of Fission Neutron Spectra With High-Energy Activation Detectors, James A. Grundl

Physics & Astronomy ETDs

The energy spectra of neutrons from the fission of U235, U233, and Pu239 have been studied with seven high-energy activation detectors covering the range 0.6 to 16 Mev. Interpretation is in terms of the Maxwellian spectral function E^1/2 exp(-E/T). By means of a unique cavity arrangement within a moderator to obtain pure thermal-neutron-induced fission neutrons, the average energies of the three spectra are found to be in the ratios

U235: U233: Pu239= (1): (1.016+or-0.003): (1.039+or-0.003).

Differences between the normalized spectra are most pronounced at high energies as exemplified by the relative Pu239:U235 flux ratios 1.17+or-0.013 for 611 Mev.

The Diffraction Of Polarized Light From A Laser By A Straight Edge, Robert Lawrence Berger

Physics & Astronomy ETDs

The purpose of this experiment was to determine the effect of the polarized light from a highly coherent light source on the diffraction pattern of a metallic straight edge.

Neuron-Proton Scattering At 23.6 Mev, Jerome G. Beery

Physics & Astronomy ETDs

The angular distribution for neutron-proton scattering was measured at a neutron energy of m3.6 MeV. The measurement was made using the Los Alamos Variable Energy Cyclotron and a liquid hydrogen bubble chamber. The angular distribution was normalized to a total n-p cross section of 408 mb.

Review Of The Physical Aspects Of Osmotic Pressure, Joseph F. Goffaux

Physics & Astronomy ETDs

It should be mentioned that this paper deals mostly with the work done by others and only a certain portion is original. The student wishes to state that he is presenting a thesis that would be considered theoretical and not empirical. The history of the work done in the field of osmotic pressure is treated at length and much of the theory used by the experimenters is derived. Many periodicals carry the papers written by the scientists of osmotic pressure and some of these men have spent perhaps fifteen of twenty years on their experiments.

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 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 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 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 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.