Malter-Driven Electron Emission as a Source of Noise in LXe TPCs

Abstract: Persistent single-electron emission ("hot spots") has been observed in multiple liquid xenon (LXe) time projection chambers (TPCs), often persisting long after ionizing events. Although typically discussed in operational terms, the behavior is consistent with Malter-type emission triggered by ion accumulation on resistive oxide surfaces. In this note, we discuss such effects and recommend material choices and design strategies to mitigate them in future detectors. This mechanism is especially relevant to experiments targeting ultra-low energy thresholds, where even small background emissions can limit sensitivity.