Photo-induced Charge Calibration R&D for nEXO

The 5-ton liquid xenon TPC of the nEXO experiment is designed to search for the elusive neutrinoless double beta decay of ¹³⁶Xe with a half-life sensitivity goal of >10²⁸ years. The challenging task of calibrating the detector, a monolithic 1.3 m diameter right cylinder involves the regular deployment of external radioactive sources and the occasional injection of ²²⁰Rn to understand the ionization and light response. Currently, there are several ongoing R&D efforts to incorporate additional calibration techniques to mitigate risk and to regularly monitor the drift electrons and the light response of silicon photomultipliers in liquid xenon. This presentation will explore the status and preliminary results from an ongoing project at the University of Massachusetts. The goal of this project is developing an optimal strategy to use multiple gold photocathodes to generate photoelectrons and to monitor the lifetime of the drifting electrons quasi-continuously in-situ in the TPC