<p> Astrophysical environments probe matter in ways impossible on Earth. In particular, matter in compact objects are extraordinarily dense. In this thesis we discuss two phenomena that may occur at high density. </p><p> First, we study toroidal topological solitons called vortons, which can occur in the kaon-condensed color-flavor-locked phase of high-density quark matter, a candidate phase for the core of some neutron stars. We show that vortons have a large radius compared to their thickness if their electrical charge is on the order of 10⁴ times the fundamental charge. We show that shielding of electric fields by electrons dramatically reduces the size of a vorton. </p><p> Second, we study an unusual phase of degenerate electrons and nonrelativistic Bose-condensed helium nuclei that may exist in helium white dwarfs. We show that this phase supports a previously-unknown gapless mode, known as the half-sound, that radically alters the material's specific heat, and can annihilate into neutrinos. We provide evidence that this neutrino radiation is negligible compared to the star's surface photoemission.</p>

We designed and built a large gas Threshold Cherenkov Counter at the Bonner Nuclear Laboratory of Rice University to be used in Fermilab-experiment E-704. We tested and calibrated the detector with an electron beam of 30 GeV/c, at Fermi National Accelerator Laboratory. The efficiency curves for the two different gases Helium and Nitrogen are presented, together with the design, characteristics and performance of the detector. An average collection efficiency of N$\sb\circ$ = 95 cm$\sp{-1}$ was achieved.

The Liquid Droplet Radiator is a proposed lightweight radiator for the dissipation of waste heat generated by power plants in space. The hot working fluid is sprayed into space as coherent streams of tiny, discrete droplets, which then cool by transient radiative heat transfer, and are later collected for recirculation. An improved, hybrid trial function is presented for the solution by Galerkin's method of the equation of radiative transfer, which governs the emission, scattering, and absorption within the layer formed by the droplet streams. The trial function compensates for the effects of the particular solution corresponding to the inhomogeneous source term. The method of analysis is demonstrated for a source function having a polynomial profile. The improved-profile Galerkin solution is then applied to a non-dimensional analysis of gray, isotropically, scattering droplet layers which are asymmetrically heated by normal, isotropic, external radiation. The analysis identifies a critical value for the magnitude of external radiation. Droplet layers exposed to external radiation greater than this critical value will heat initially, and then either recover and cool, or for magnitudes sufficiently stronger than the critical value will achieve a state of equilibrium.

Heat transfer in a radiatively participating medium involves higher coupling than is typical for pure conduction and/or convection problems. Consequently, standard discretizing techniques such as partitioning regions of a finite volume domain on separate processors are inefficient. Additionally, standard angular decompositions may introduce discontinuities into the solution which are difficult to model accurately. A scalable method for parallelizing the radiative transport equation is presented. A standard discrete ordinates formulation is used to transform the integro-differential equation into a system of partial differential equations. The resulting system of equations is then solved by an optimal grid-independent, sequential-function approach that captures discontinuities accurately without additional user interaction. Results for one- and two-dimensional cases are given.

Collinear fast-beam laser spectroscopy is a method of studying atomic and ionic hyperfine structure where a particle beam and a laser beam are superposed along the same line. Such a facility exists at ISAC, TRIUMF, Vancouver, BC, and was designed especially for polarising radioactive beams of alkali metals. / In order to produce polarised fluorine for the use in NMR, the hyperfine structure of the 3s 4P 5/2 and 3p 4D 7/2 states has to be known. The hyperfine coefficients for those two levels are measured for the first time to be A = 2645.6(6) MHz and A = 1565.6(4)MHz respectively. The 3p 4D5/2 state is also studied to measure the metastable atom fraction and its hyperfine constant is measured to be A = 1148(5)MHz. / A study of lanthanum ions is also carried out. Spectra for the 6 s2 1S0 to 5 d6p Do13 transition are measured with stable 139La to evaluate the sensitivity of the equipment and with radioactive 139La for preliminary commissioning of the isotope shift study.

Thesis (Ph.D.)--University of California, San Francisco, 2007. / Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7476. Adviser: Jean Pouliot.

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acase@tulane.edu

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