Dissertation Defense: Elizabeth Boulton, Yale University, “Applications of Two-Phase Xenon Time Projection Chambers: Searching for Dark Matter and Special Nuclear Materials”

Event time: 
Friday, May 18, 2018 - 10:00am to 11:00am
Sloane Physics Laboratory (SPL), Room 56 See map
217 Prospect Street
New Haven, CT 06511
Event description: 

Over the past four decays, Liquid xenon has emerged as a popular medium for direct detection of dark matter. The Large Underground Xenon (LUX) experiment utilized a 300 kg two-phase xenon detector to set a world-leading limit on the WIMP spin-independent cross-section and WIMP mass parameter space with 332 live-days of data collection. This analysis proved especially challenging due to non-uniform, time-evolving drift fields during the WIMP search run, and it required the use of novel calibration systems and innovative analysis techniques. The LUX detector was also used to investigate properties of liquid xenon in order to further research beyond dark matter. Specifically xenon’s response to low- energy recoils O(< 5 keV) is not thoroughly understood, and yet it is vitally important to the search for axions, neutrino-less double beta decays, and the neutrino magnetic moment. To better understand this low energy regime, an 37Ar source (which produces low-energy, mono- energetic recoils) was developed and used to calibrate the detector. These measurements were compared to the 37Ar measurements in another two-phase xenon detector: the Particle Identification in Xenon at Yale (PIXeY) detector. Liquid xenon detectors excel at detecting rare events. In addition to searching for dark matter, this makes them potentially well suited for detecting the low decay rates of special nuclear materials (SNM). The PIXeY detector and the Compton-imaging Detector in Xenon (CoDeX), were used to investigate the feasibility of creating a two-phase xenon Compton-imager to detect SNM.

Thesis Advisor: Daniel McKinsey