This thesis studies superradiance and subradiance in the normal modes of excitation of systems of resonant nuclei. The nuclei are treated as classical electric dipole oscillators interacting through their radiation fields. This coupling radically alters the radiative decay of the system relative to the decay of an isolated nucleus, and leads to both superradiant and subradiant states with strongly enhanced or suppressed radiative decay rates, and with normal mode frequencies which can be strongly shifted from the natural resonance frequency. This issue is of considerable current interest because it is now possible to create spatially coherent single exciton nuclear states by illuminating crystals containing resonant Mossbauer nuclei with synchrotron radiation pulses. The purpose of this thesis is to solve for the radiative eigenmodes in a system of nuclei and to investigate superradiance and subradiance both in the eigenmode solutions and in the synchrotron radiation produced nuclear exciton state.

This research is conducted as a R&D work for the PHENIX experiment of the relativistic heavy ion collider (RHIC) at Brookhaven National Laboratory (BNL), in an effort to develop a multi-wire proportional chamber (MWPC) using a new pixel cathode pad readout method. The pads are formed by linking the pixels in a special pattern and the image charge signals on the pads are read by highly integrated CMOS digital electronic chips with chip-on-board (COB) technology. Two prototype pixel pad chambers, PC1 and PC3, were designed and constructed. The chambers were tested with high energy particle beams at BNL. This work demonstrates the feasibility and affordability of constructing and operating the pixel pad chambers with large number of channels, using the technology adopted here. Good spatial resolutions equal to about one-half the cell dimensions both along and perpendicular to the wire direction ($4mm$ for PC1 and $8mm$ for PC3) have been achieved. Charged particle track reconstruction efficiency and other chamber characteristics are also discussed.

A new prototype of multiwire proportional chamber (MWPC) with pixel configurated pad cathode was built as a joint effort by McGill University, Lund University and Oak Ridge National Laboratory as part of the development of the tracking system of the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). This thesis first describes the implementation of a new readout electronics for the pad chambers. In this electronics, the charge of the pads is digitized using a preamplifier/shaper/discriminator integrated CMOS chip with adjustable threshold. All chips and components are mounted on specially designed 48-channel readout cards using chip-on-board (COB) technology. Using this new readout, the performance of the pad chamber is tested with cosmic rays and X-ray source. The prototype response, efficiency and gain are measured as functions of detector operating conditions. The operation of the chamber shows a very good stability over long periods of testing. Excellent efficiencies, above 99%, are observed in tests using discriminator thresholds between 2--4 fC, which represents 1--1.5% of the most probable anode charge produced at a normal anode voltage of 1850V. Under this conditions, the reconstructed hit patterns are relatively small. This is leading to a very good position resolution of about half of the cell size. An excellent description of chamber behavior was obtained using Monte Carlo simulations. showing that we can use these simulations to predict and optimize the performance of such chamber.

Thesis (Ph.D.)--Indiana University, Dept. of Physics, 2008. / Title from PDF t.p. (viewed on Jul 28, 2009). Source: Dissertation Abstracts International, Volume: 69-12, Section: B, page: 7573. Adviser: Michael Snow.

Thesis (M.S. in Physics)--Naval Postgraduate School, December 1990. / Thesis Advisor(s): Weaver, Wm. Bruce. Second Reader: Cleary, David D. "December 1990." Description based on title screen as viewed on March 29, 2010. DTIC Identifier(s): Atmosphere Models, Photons, Parameters, Photosphere, Theses. Author(s) subject terms: Simulation, Solar absorption lines, Radiative transfer theory. Includes bibliographical references (p. 56-57). Also available in print.

Thesis (Ph. D.)--Syracuse University, 2003. / "Publication number AAT 3113223."

Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.)--University of Tennessee. / "Date issued Aug 27 1962". Bibliography references : p. 125-133.

Thesis (Ph.D.)--Indiana University, Dept. of Physics, 2005. / Source: Dissertation Abstracts International, Volume: 66-08, Section: B, page: 4269. Adviser: Charles J. Horowitz. Title from dissertation home page (viewed Oct. 10, 2006).

Thesis (Ph.D.)--Indiana University, Dept. of Physics, 2006. / "Title from dissertation home page (viewed June 28, 2007)." Source: Dissertation Abstracts International, Volume: 67-06, Section: B, page: 3202. Adviser: Shyh-Yuan Lee.