Speaker
Description
nEXO is a next-generation search for the neutrinoless double beta decay (0𝜈𝛽𝛽) of 136Xe using a 5-tonne, monolithic liquid xenon time projection chamber (TPC). To optimize the event reconstruction and energy resolution of the TPC, calibrations are needed to map the position- and time- dependent detector response. We will describe recent work studying the feasibility of neutron-activated 127Xe as a monoenergetic source that can be dissolved directly in the liquid xenon, providing uniform calibrations of the entire detector. The 36.3 day half-life of 127Xe and its small 𝑄-value compared to that of 136Xe 0𝜈𝛽𝛽 would allow a small activity to be maintained continuously in the detector during normal operations without introducing additional backgrounds, thereby enabling in-situ calibration and monitoring of the detector response. We describe an experimental demonstration of such a source in a prototype liquid xenon TPC, as well as simulations to model possible calibrations in nEXO. We show that a 127Xe source can achieve the precision required to meet nEXO's energy resolution targets, maximizing nEXO's sensitivity to neutrinoless double beta decay.
