The Search for Astrophysical Ultra-High Energy Neutrinos Using Radio Detection Techniques

Ultra-high energy (UHE) neutrino astronomy would allow for the highest energy observation of extragalactic sources and the observation of extremely distant sources in the universe. A flux of UHE neutrinos is expected from interactions of UHE cosmic-ray protons with the cosmic microwave background. The ANITA (ANtarctic Impulsive Transient Antenna) experiment. a NASA Long Duration Balloon omission, searches for radio emission arising from the Askaryan charge excess that develops in electromagnetic particle cascades induced by UHE neutrinos with energy greater than 1018 eV interacting in Antarctic ice. The second flight of the ANITA experiment launched on December 21st, 2008, and collected data for 31 days. In Chapters 2 and 3, I describe the ANITA-II instrument and the calibration of the instrument in detail. Chapters 4 and 5 contain a discussion of a blind analysis of ANITA-II data in which I find 2 surviving neutrino candidate events on a background (anthropogenic and thermal noise) of 0.97+/-0.42 events. I set the strongest limit to dare for 1018 -- 1021 eV cosmic neutrinos, excluding several current cosmogenic neutrino models. In Chapters 6 and 7, I investigate possibilities for next-generation experiments for radio detection of UHE neutrinos. In Chapter 6. I discuss the results of radio attenuation length measurements of rock salt taken at two different salt mines. Chapter 7 is a description of a simulation for a next-generation, ground-based experiment in Antarctica.