Improving nEXO Sensitivity with Radon Distillation

nEXO is a 5 tonne neutrino-less double beta (0vBB) experiment looking for this Standard Model forbidden decay in Xe-136. If these lepton number violating decay are observed it would mean that neutrinos are Majorana fermions, i.e. their own antiparticle. The nEXO experiment is designed to achieve a 1.35 x 10^28 year half-life sensitivity (at 90% confidence level), about 10 events in 10 years of running. In nEXO, liquefied enriched xenon (LXe) fills a single drift region time projection chamber with scintillation readout. The detector is built with ultra-low radioactivity materials, including an electroformed copper xenon vessel. The sensitivity of the experiment could be further increased by virtually eliminating radon dissolved in the LXe. A cryogenic distillation column that reduces the radon in xenon 100-fold would increase nEXO’s sensitivity to >1.7x10^28 years. We will report on the progress of R&D on cryogenic distillation of LXe ongoing at the SLAC National Accelerator Laboratory.