Toward Background-Free Methods to Search For Majorana Neutrinos in Xenon Gas
Abstract
Since the observation of double beta decay 33 years ago the search for neu- trinoless double beta decay has been underway. This is due to the fact that a robust observation of neutrinoless double beta decay is currently the most sen- sitive method to determine the Majorana nature of the neutrino. Such searches have been at the forefront for developing new methods and techniques that are required for observing such rare processes.
The detection of the single barium ion produced as a result of the double beta decay of 136Xe would enable a new class of ultra-low background neutrinoless double beta decay experiments. However, despite 19 years of R&D, a credible method to collect and identify individual barium ions in bulk xenon has remained elusive.
This dissertation is comprised of four-parts, which focus on new experi- mental methods and techniques in order to reduce or eliminate backgrounds completely, and the impact such advancements would have on experimental sensitivity to neutrinoless double beta decay.
Part I motivates the search for neutrinoless double beta decay. Starting from the origins of the neutrino mass and how it is possibly connected to the matter anti-matter asymmetry observed today.
Part II concerns the NEXT experimental program and focuses on the operat- ing principles of gaseous xenon radiation detectors and their advantages.
Part III explores the fundamentals of gas physics with a focus on enhancing current detectors performance.
Part IV illustrates the advancements made in detecting the daughter ion, which include the development of a novel microscopy technique.