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UBC Theses and Dissertations

A linear Paul trap for barium tagging of neutrinoless double beta decay in nEXO Lan, Yang


nEXO is the next-generation Enriched Xenon Observatory searching for neutrinoless double beta decay (0νββ) in ¹³⁶Xe. If observed, 0νββ will validate the neutrino to be its own anti-particle and determine the absolute mass scale of the neutrinos. nEXO's sensitivity is limited by the background level. Barium tagging is the ultimate background rejection method using the coincidence detection of ¹³⁶Ba as the daughter nucleus. A linear Paul trap (LPT) is needed for the barium tagging concept in nEXO or a future gaseous experiment. The theory of an ideal LPT was studied from first principles to obtain analytical solutions of the trapped ions and to validate a simulation method. Then simulations were done to optimize the design of a realistic final LPT. Meanwhile, prototypes of key components of the LPT were built for the experimental developments. A prototype of the LPT's quadrupole mass filter (QMF) achieved mass resolving power m/Δm around 140 and exceeded its requirement. A 3D printed prototype of the novel ion cooler demonstrated successful ion cooling, trapping and ejection. Based on the progress with the prototypes, improvements were made to the design of the final setup. The final LPT will be installed between an RF funnel and a high precision mass spectrometer for barium tagging of nEXO.

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