RICE Limits on the Diffuse Ultra-High Energy Neutrino Flux

New limits are presented on ultrahigh-energy neutrino fluxes above 1017 eV based on data collected by the Radio Ice Cherenkov Experiment (RICE) at the South Pole from 1999-2005. The estimation of backgrounds, procedures used for the dedicated neutrino search, and our Monte Carlo simulation are discussed. An enlarged data set and a more detailed study of hadronic showers results in a sensitivity improvement of more than one order of magnitude compared to our previously published results. Examination of the full RICE data set yields zero acceptable neutrino candidates, and 95% confidence level limits are presented that rule out the most intense flux model projections