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 Degree Discipline: Physics
Gamma Rays from Cs¹³³ by Inelastic Scattering of Neutrons

Gamma Rays from Cs¹³³ by Inelastic Scattering of Neutrons

Date: August 1960
Creator: McDonald, Perry Frank
Description: The purpose of this investigation was to observe the excited states of the Cs¹³³ nucleus when neutrons are inelastically scattered from the nucleus.
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Gamma Rays from Neutron Excitation of Cs133

Gamma Rays from Neutron Excitation of Cs133

Date: January 1959
Creator: Lamb, Billy Leonard
Description: This thesis explores gamma rays from neutron excitation of Cs133.
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Gamma Rays Resulting from Neutron Scattering in Cesium

Gamma Rays Resulting from Neutron Scattering in Cesium

Date: January 1967
Creator: McAnally, Michael A.
Description: The purpose of this investigation was to attempt to resolve the energy levels of Cs133 that can be excited by inelastic scattering of 14 Mev neutrons.
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Growing carbon nanotubes by chemical vapor deposition technique.

Growing carbon nanotubes by chemical vapor deposition technique.

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Date: May 2000
Creator: Rajan, Harihar V.
Description: Carbon nanotubes were synthesized in the laboratory using chemical vapor deposition at different methane concentration. I found that a methane concentration of 4 sccm was ideal for well recognizable carbon nanotubes. A higher concentration led to fewer nanotube growth and silicon carbide structure. Coating the sample first with Fe(NO3)3 created a catalyst base on the substrate for the nanotube to adhere and grow on.
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Growth and Characterization of β-Iron Disilicide, β-Iron Silicon Germanide, and Osmium Silicides

Growth and Characterization of β-Iron Disilicide, β-Iron Silicon Germanide, and Osmium Silicides

Date: August 2009
Creator: Cottier, Ryan James
Description: The semiconducting silicides offer significant potential for use in optoelectronic devices. Full implementation of the materials, however, requires the ability to tailor the energy gap and band structure to permit the synthesis of heterojunctions. One promising approach is to alloy the silicides with Ge. As part of an investigation into the synthesis of semiconducting silicide heterostructures, a series of β-Fe(Si1−xGex)2 epilayer samples, with nominal alloy content in the range 0 < x < 0.15, have been prepared by molecular beam epitaxy on Si(100). I present results of the epitaxial and crystalline quality of the films, as determined by reflection high-energy electron diffraction, Rutherford backscattering spectroscopy, and double crystal x-ray diffraction, and of the band gap dependence on the alloy composition, as determined by Fourier transform infrared spectroscopy. A reduction in band gap was observed with increasing Ge content, in agreement with previous theoretical predictions. However Ge segregation was also observed in β-Fe(Si1−xGex)2 epilayers when x > 0.04. Osmium silicide films have been grown by molecular beam epitaxy on Si(100). The silicides have been grown using e-beam evaporation sources for both Os and Si onto Si(100) substrates at varying growth rates and temperatures ranging from 600-700ºC. The resulting films have been ...
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Gurevich Magnetomorphic Oscillations in Single Crystals of Aluminum at Helium Temperatures

Gurevich Magnetomorphic Oscillations in Single Crystals of Aluminum at Helium Temperatures

Date: August 1967
Creator: Mollenkopf, Howard Charles
Description: The Sondheimer theory was tested by looking for oscillatory phenomena in a group of single crystals representing a range in dimensions from matchbox geometry to thin-film geometry. The single crystals were identical with respect to impurity content, strain, orientation, surface condition, and probe placement.
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High Efficiency High Power Blue Laser by Resonant Doubling in PPKTP

High Efficiency High Power Blue Laser by Resonant Doubling in PPKTP

Date: August 2011
Creator: Danekar, Koustubh
Description: I developed a high power blue laser for use in scientific and technical applications (eg. precision spectroscopy, semiconductor inspection, flow cytometry, etc). It is linearly polarized, single longitudinal and single transverse mode, and a convenient fiber coupled continuous wave (cw) laser source. My technique employs external cavity frequency doubling and provides better power and beam quality than commercially available blue diode lasers. I use a fiber Bragg grating (FBG) stabilized infrared (IR) semiconductor laser source with a polarization maintaining (PM) fiber coupled output. Using a custom made optical and mechanical design this output is coupled with a mode matching efficiency of 96% into the doubling cavity. With this carefully designed and optimized cavity, measurements were carried out at various fundamental input powers. A net efficie ncy of 81 % with an output power of 680 mW at 486 nm was obtained using 840 mW of IR input. Also I report an 87.5 % net efficiency in coupling of blue light from servo locked cavity into a single mode PM fiber. Thus I have demonstrated a total fiber to fiber efficiency of 71% can be achieved in our approach using periodically poled potassium titanyl phosphate (PPKTP). To obtain these results, all ...
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Homogeneous Canonical Formalism and Relativistic Wave Equations

Homogeneous Canonical Formalism and Relativistic Wave Equations

Date: January 1967
Creator: Jackson, Albert A.
Description: This thesis presents a development of classical canonical formalism and the usual transition schema to quantum dynamics. The question of transition from relativistic mechanics to relativistic quantum dynamics is answered by developing a homogeneous formalism which is relativistically invariant. Using this formalism the Klein-Gordon equation is derived as the relativistic analog of the Schroedinger equation. Using this formalism further, a method of generating other relativistic equations (with spin) is presented.
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The Interactions of Plasma with Low-k Dielectrics: Fundamental Damage and Protection Mechanisms

The Interactions of Plasma with Low-k Dielectrics: Fundamental Damage and Protection Mechanisms

Date: August 2011
Creator: Behera, Swayambhu Prasad
Description: Nanoporous low-k dielectrics are used for integrated circuit interconnects to reduce the propagation delays, and cross talk noise between metal wires as an alternative material for SiO2. These materials, typically organosilicate glass (OSG) films, are exposed to oxygen plasmas during photoresist stripping and related processes which substantially damage the film by abstracting carbon, incorporating O and OH, eventually leading to significantly increased k values. Systematic studies have been performed to understand the oxygen plasma-induced damage mechanisms on different low-k OSG films of various porosity and pore interconnectedness. Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy and atomic force microscopy are used to understand the damage kinetics of O radicals, ultraviolet photons and charged species, and possible ways to control the carbon loss from the film. FTIR results demonstrate that O radical present in the plasma is primarily responsible for carbon abstraction and this is governed by diffusion mechanism involving interconnected film nanopores. The loss of carbon from the film can be controlled by closing the pore interconnections, He plasma pretreatment is an effective way to control the damage at longer exposure by closing the connections between the pores.
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An Investigation for Gamma Rays Resulting from the Bombardment of As75 with 14 Mev Neutrons

An Investigation for Gamma Rays Resulting from the Bombardment of As75 with 14 Mev Neutrons

Date: 1957
Creator: Givens, Wyatt Wendell
Description: It is the purpose of this paper to set forth the method and results of studying the gamma rays resulting from the bombardment of As75 with approximately 14 Mev neutrons. The source of these neutrons was the H3(d,n)He4 reaction. The deuterons of 325 Kev energy were obtained from a Van de Graff electrostatic accelerator. A NaI scintillation spectrometer was used to determine the gamma-ray energies.
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