Development of a Xe-127 calibration source for nEXO

We study a possible calibration technique for the nEXO experiment using a Xe-127 electron capture source. nEXO is a next-generation search for neutrinoless double beta decay (0 nu beta beta) that will use a 5-tonne, monolithic liquid xenon time projection chamber (TPC). The xenon, used both as source and detection medium, will be enriched to 90% in Xe-136. To optimize the event reconstruction and energy resolution, calibrations are needed to map the position- and time-dependent detector response. The 36.3 day half-life of Xe-127 and its small Q-value compared to that of Xe-136 0 nu beta beta 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. In this work we describe a process for producing the source and preliminary experimental tests. We then use simulations to project the precision with which such a source could calibrate spatial corrections to the light and charge response of the nEXO TPC.