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Elastic Scattering Of 1.33 Mev Gamma Rays From Lead, William Jack Merrow

Masters Theses

No abstract provided.

Elastic Scattering Of 1.33 Mev Gamma Rays From Uranium, David Rood Schwandt

Masters Theses

No abstract provided.

Fabrication Of Lithium Drifted Germanium Detectors Of Planar Structures, Khin M. Yin

Masters Theses

No abstract provided.

Lattice Dynamics And Second-Order Raman Spectrum Of Naf, John R. Hardy, A. M. Karo, I. W. Morrison, C. T. Sennett, J. P. Russell

John R. Hardy Papers

The second-order Raman spectrum of NaF has been measured using an argon laser source. For a light beam incident along the [010] direction, polarized along the [001] direction, and viewed along the [100] direction, the scattered radiation is almost completely polarized. It is shown theoretically that it is possible to account for the polarization and the detailed shape of the observed spectrum within the experimental resolution using a Raman polarizability tensor whose second derivatives with respect to nuclear displacements depend only on the positions of first neighbors in the crystal, provided one uses the phonon frequencies derived from a deformation …

Multiple Charge States, Hyperfine Interactions, And Relaxation Processes Of Fe In 57Co-Doped Mgo, J. Chappert, Richard B. Frankel, A. Misetich, N. A. Blum

Physics

The Mössbauer spectra of cobalt-57-doped magnesium oxide have been studied between 1.3 and 550°K in external magnetic fields of up to 135 kOe for both single-crystal and polycrystalline samples. At room temperature and zero external magnetic field, the velocity spectrum is composed of three single lines, attributed to monovalent, divalent, and trivalent iron. In certain samples, for T2+ line undergoes a transition to a quadrupole doublet with a splitting ΔE_Q=0.30±0.02 mm/sec, while in certain other samples, annealed differently, no doublet is observed down to 1.5°K. The first case is in quantitative agreement with a random-strain model …

A Shock Tube Study Of Recombination In The Lean Hydrogen-Oxygen Reaction Based On The Infrared Emission From Water Vapor, Larry S. Blair

Physics & Astronomy ETDs

ABSTRACT

Recombination in the hydrogen-oxygen reaction has been studied by monitoring the growth of infrared emission at 2.7 microns from water vapor as it is formed behind incident shock waves. Experiments were carried out in gas mixtures with hydrogen-to-oxygen ratios between 1.0 and 0.33 and temperatures between 1435° and 1868°K. Reactants were diluted with 92-98% argon. The validity of the transparent gas approxi­mation (emission intensity proportional to (H20]) and the relationship between emission intensity and temperature were established by cali­bration experiments in which mixtures of water vapor and argon were shock-heated to temperatures between 1328° and 1982°K. Analysis of H20-emission …

Pulsed Nmr By Tone-Burst Generation, David C. Look, Donald R. Locker

Physics Faculty Publications

No abstract provided.

Local Moment Formation And Resistivity Minima In Coal Alloys, G.R. Caskey, David J. Sellmyer

David Sellmyer Publications

Measurements of electrical resistivity, thermoelectric power, and magnetoresistance have been made from 1.4° to 300°K in alloys of 48%–57% cobalt in aluminum. At the equiatomic composition, CoAl has the CsCl structure. Resistance minima were observed in the vicinity of 30°K for cobalt concentrations between 50.4% and 51.5%. Below the resistance minima there is a temperature region where the dependence is approximately logarithmic before it saturates at about 1.4°K. The depth of the minima [ρ(1.4°K)– ρ( T_min)] and the thermopower at 4.2°K both show rather sharp peaks as a function of concentration in the vicinity of 50.5% cobalt. The …

Meteorological Effects On Cosmic Rays At Albuquerque, New Mexico., David Nason Glidden

Physics & Astronomy ETDs

Ground-based observations of cosmic-ray intensity have the disadvantage of being more sensitive to variations of atmospheric temperature and pressure than to the more interesting variations in the primary cosmic radiation. It is, therefore, imperative to correct the recorded cosmic-ray intensity for variations of atmospheric origin before studies can be made of the smaller variations of the primary cosmic ray intensity.

In this thesis an attempt has been made to remove the variations of atmospheric origin from the cosmic-ray intensity recorded simultaneously by a neutron monitor and a meson telescope located at Albuquerque, New Mexico. It was found that the neutron …

Electron Energy Dissipation, E. J. Kobetich, Robert Katz

Robert Katz Publications

A new algorithm for the computation of the energy dissipated by normally incident, monoenergetic electron beams, provides good agreement with experimental data and with the computations of Spencer.

Quasifree Knockout Of Deuterons In The ⁶Li(Α,Αd)⁴He Reaction At 23.6 Mev, K. Bähr, T. Becker, Oleksa-Myron Bilaniuk, R. Jahr

Physics & Astronomy Faculty Works

α−d correlations in quasi-elastic scattering of 23.6-MeV α particles on the deuteron cluster of the ⁶Li target were measured in and off the principal reaction plane. Despite the low c.m. energy of 14.2 MeV, the impulse approximation provides a reasonable description of the quasifree process. Computations were based on the asymptotic α−d S-state wave function and on the cluster-model wave function of ⁶Li. Insensitivity of the fits to the details of the ⁶Li cluster-model wave function indicates an extreme surface reaction mechanism. The full width at half-maximum of the spectator momentum distribution was found to be 48±6 MeV/c. By comparing …

Projected Hartree Product Wavefunctions. Ii. General Considerations Of Young Operators, Gordon A. Gallup

Gordon Gallup Publications

A discussion is given of the forms of two specific and one general Young operator for the irreducible representations of S_n important for fermion space functions. Comparisons are made of the projected Hartree product version of Löwdon's projected Hartree–Fock method with CI calculations. ©1969 American Institute of Physics

Projected Hartree Product Wavefunctions. Iii. Comparison With The Ci Method For H2, R.C. Morrison, Gordon A. Gallup

Gordon Gallup Publications

Calculations of the energy of H₂ have been performed using both the projected Hartree–Fock (PHF) method and a full CI method in the same basis for comparison of the two methods. It is discovered that PHF can account for 86% of the correlation energy, whereas CI will account for 88% of the correlation energy. ©1969 American Institute of Physics

Absence Of Induced Magnetic Fields At Gd Nuclei In Gdfe2, H. Maletta, Richard B. Frankel, W. Henning, R. L. Mössbauer

Physics

Measurements of the magnetic hyperfine field at ¹¹⁵Gd in GdFe₂ in external magnetic fields reveal the absence of induced magnetic fields, in disagreement with other reported data.

Application Of The Method Of Lattice Statics To Vacancies In Na, K, Rb, And Cs, John W. Flocken, John R. Hardy

John R. Hardy Papers

We have calculated the lattice distortion produced by a single vacancy in Na, K, Rb, and Cs. The calculations have been carried out using the technique of lattice statics, which is based on the Fourier transformation of the direct-space equilibrium equations, making consistent use of discrete lattice theory. Three distinct types of potential have been used to describe the interactions between the host atoms. The first of these applies only to sodium, and contains an ion-electron-ion term derived from the measured phonon dispersion curves. The second applies only to potassium, and has been similarly obtained. The third is based on …

Quadrupole Moment Of 57FeM, J. Chappert, Richard B. Frankel, A. Misetich, N. A. Blum

Physics

The quadrupole splitting induced by a magnetic field at low temperatures has been measured by Mössbauer spectroscopy for Fe²⁺ in MgO; a value of +0.21 ± 0.03 barn for the quadrupole moment of ⁵⁷Fe^m is obtained.

Summation Over Feynman Histories In Polar Coordinates, David Peak, A Inomata

All Physics Faculty Publications

Use of polar coordinates is examined in performing summation over all Feynman histories. Several relationships for the Lagrangian path integral and the Hamiltonian path integral are derived in the central‐force problem. Applications are made for a harmonic oscillator, a charged particle in a uniform magnetic field, a particle in an inverse‐square potential, and a rigid rotator. Transformations from Cartesian to polar coordinates in path integrals are rather different from those in ordinary calculus and this complicates evaluation of path integrals in polars. However, it is observed that for systems of central symmetry use of polars is often advantageous over Cartesians.

Equilibrium Concentration Of Impurity-Vacancy Complexes, Robert Fuller, H.B. Rosenstock

Robert G. Fuller Publications

In recent years the transport properties of alkali halide crystals have been discussed in terms of fi ve defects, i.e. isolated anion vacancies, isolated cation vacancies, isolated impurity ions, nearest neighbor vacancies of opposite electric charge (divacancies), and nearest neighbor impurity- vacancy complexes [1]. Originally these defects were treated as noninteracting particles located at appropriate lattice sites (the presence of divacancies and complexes was not assumed) and the defect concentrations were obtained from statistical mechanics. Subsequently the defects were allowed to interact with oppositely charged defects located at nearest neighbor lattice sites and the concentrations of divacancies and complexes were …

A Determination Of The Speed Of Light By The Phase-Shift Method, John Rogers, Ronnie Mcmillan, Robert Pickett, Richard A. Anderson

Physics Faculty Research & Creative Works

A low-frequency, phase-shift method for the measurement of the speed of light has been developed. This technique gives results commensurate with other advanced laboratory methods. One advantage of this technique is that the apparatus is of reasonable size and most of the circuitry involves widely known amateur radio techniques. Furthermore, our use of a low modulating frequency permits use of the solid-state, electro-optical light shutter. This eliminates the rather dangerous liquid Kerr cell, thus making our apparatus more acceptable to application in the undergraduate advanced laboratory. From a pedagogical point of view, the student is allowed to use and become …

A Study Of The Evaporation Rates Of Small Freely Falling Water Droplets, Hugh Alan Duguid

Masters Theses

"The evaporation rates of small (radium 3-9µ), freely falling water droplets were determined. the droplets, produced in a diffusion cloud chamber, were allowed to fall through air of known relative humidity (95-100%) and at three ambient temperatures (25C, 30C, and 35C) in a vertical drift tube. the rates of evaporation were ascertained by recording the drop positions on film at fixed time intervals. The results are compared with several existing theories, and are found to lie between the formulation of Kinzer and Gunn, and the quasistationary theory based on Maxwell's equation"--Abstract, page ii.

A Survey Of The Methods For Producing Extremely Low Temperatures, Patricia M. Boise

Departmental Honors & Graduate Capstone Projects

A Survey of the Methods for Producing Extremely Low Temperatures

Vapor Phase Clustering Model For Water, Richard W. Bolander

Doctoral Dissertations

"Although nucleation phenomena are among the most widespread of all naturally occurring phenomena, even the simplest of nucleation processes, homogeneous nucleation, is poorly understood, particularly the homogeneous nucleation of liquid droplets from water vapor. Homogeneous nucleation involves only molecules of a single substance and does not include the complicating effects due to a substrate or piece of foreign matter. The semiphenomenological liquid drop theories developed nearly three decades ago differ in relatively minor details, with the crucial element of the theory being the derivation of the free energy of formation of the clusters. The clusters are viewed as well-defined incompressible …

A.C. Hall Effect Measurements On Very High Resistivity Materials Exhibiting Electrode Polarization, James Dale Boyd

Doctoral Dissertations

"A variable frequency, a.c. Hall effect measurement technique has been designed for mobility studies in very high resistivity (>10⁹ ohm·cm) materials exhibiting electrode space charge polarization effects. It incorporates a neutralized input capacitance preamplifier detector which reduces the total input shunting capacitance, including the sample interelectrode capacitances, to a very low, definable value (<0.1 pf) and thereby provides very high and well defined a.c. detector input impedances (4 x 10⁹ and 7 x 10⁹ ohms at 600 and 200 Hz, respectively). Lumped parameter equivalent circuits have been defined to approximate the electrical behavior of sample materials in the measurement configuration. These equivalent circuits, together with independent measurements of the detector input and sample impedances, allow one to correct the detected Hall voltage and obtain the true value from which mobility data may be derived. The validity of these circuits has been established by independent a.c. and d.c. measurements on photoconductive CdS (dark resistivity >10¹⁰ ohm·cm) which exhibited maximum differences of less than 4%. The existing literature has been critically reviewed and the measurement criteria established by this study have been applied to resolve differences in reported data and to suggest improvements in the resolution of previously employed experimental …

A Study Of The Energy Loss Spectra Induced By Impact Of 23-125 Kev Protons On Helium Atoms, Franklin Dean Schowengerdt

Doctoral Dissertations

"Results of a study of the inelastic energy loss spectra induced by the impact of protons on gaseous helium at energies of 25 to 125 keV are reported. The spectra were obtained by sending an accelerated beam of protons through a chamber containing the helium target gas, mass-analyzing the forward-scattered beam, then decelerating the beam to a low, well-defined energy for energy analysis and detection. The accelerating potential was varied to produce the spectra. An energy resolution of 2 eV was obtained. Apparent differential cross sections and absolute total cross sections were obtained from the spectra. Total cross sections for …

Low-Lying Levels In Some Spherical And Rotational Nuclides By Coulomb Excitation And Radiative Capture Of Thermal Neutrons, Donald Allan Mcclure

Doctoral Dissertations

"The work presented in this dissertation was performed in order to obtain additional information on the level schemes and decay properties of several nuclei in an attempt to explain the observations in terms of an applicable nuclear model. Various nuclear models are discussed in Section II. A general review from the classical point of view of the Coulomb excitation reaction is discussed in Section III and the thermal-neutron-capture reaction is outlined in Section IV. The experimental equipment and procedure is discussed in Section V in which the ramper method of energy determination is outlined. This method allows the measurement of …

MöSsbauer Effect Studies Of Ferroelectric Phase Transitions In The Pbzro₃ - Pbtio₃ - Bifeo₃ Ternary System, James P. Canner

Doctoral Dissertations

"The Mössbauer Effect was used to measure the phase transitions in the following ferroelectric compounds: 95% PbZ4₀.₈Ti₀.₂ - 5% BiFeO₃ [and] 95% PbZ4₀.₇Ti₀.₃ - 5% BiFeO₃ and in the antiferroelectric compound: 95% PbZrO₃ - 5% BiFeO₃. The parameters obtained were the area under the resonance peak, the isomer shift, and the electric quadrupole splitting, all as a function of temperature. The ionicity, electric field gradient, and Debye temperature were determined for room temperature. The data are discussed in terms of the lattice vibration model of ferroelectrics and antiferroelectrics, and the structural phase transitions as recently defined for these compounds. The …

Radiative Lifetime Of The B¹Σ⁺ And B³Σ⁺ States Of Carbon Monoxide, John Robert Rogers

Doctoral Dissertations

"The radiative lifetimes of the B¹Σ⁺ and b³Σ⁺ excited states of carbon monoxide were measured at six different pressures: 10, 25, 50, 75, 100, and 125 microns of Hg. The lifetimes were obtained by observation of the radiative decay of the (0,0), (0,1), (0,2), and (1,1) bands of the Angstrom system and the radiative decay of the (0,1), (0,2), (0,3), and (0,4) bands of the Third Positive system. No pressure dependence of the lifetimes was observed for either system. The average lifetime of the v' = 0 vibrational level of the B¹Σ⁺ state was found to be 24.4 x 10⁻⁹ …

The Statistics Of Finite, One Dimensional Lattice Fluids, John Roger Glaese

Doctoral Dissertations

"A one dimensional lattice fluid in which particles are allowed to assume only discrete positions is proposed. Particles are free to move from one lattice site to another interacting through a variety of potentials, including the Lennard-Jones type. The model allows the partition function to be evaluated as a discrete sum over the allowable configurations. Both the canonical ensemble and grand ensemble are treated by computer and a third, the pressure ensemble, is considered and shown to be useful in the theoretical treatment of lattice systems. The thermodynamic behavior of various systems is investigated in both the canonical and grand …

Infrared Cooling Near Atmospheric Temperature Inversions And Absorber Concentration Variations, Joey Keith Tuttle

Masters Theses

"Cooling due to infrared radiation near temperature inversions is investigated. Temperature inversions tend to hold pollution below the inversion level. The pollution itself may contribute to the stability of the inversion by selectively cooling certain portions of the atmosphere. A method is developed for evaluating infrared cooling rates at discreet points in the atmosphere. Several sample calculations are given to demonstrate the effects of variations of absorber concentration and lapse rate"--Abstract, page i.

An Experimental Comparison Of Various Nuclei Counters, Joel William Mansell

Masters Theses

"A series of simultaneous nuclei concentration measurements, with four different nuclei counters, have been made. these counters were a Pollak and a Gardner counter supplied by Mr. Paul Allee of the Environmental Science Services Administration, Boulder, Colorado, and a Pollak and a G.E. counter supplied; by Mr. Norman White of the National Center for Air Pollution Control, Cincinnati, Ohio. In the absence of any knowledge of the absolute concentrations in the samples, the data for each of the individual counters have been compared to the averages computed from all four counters. The results of these comparisons indicate the following: (1) …