The CAGE Scanner: Developing PSD Techniques for LEGEND-1000

The LEGEND experiment is searching for 0νββ decay in high-purity germanium detectors enriched in ⁷⁶Ge. LEGEND-1000, a next-generation ton-scale experiment, targets a sensitivity that would fully cover the inverted mass hierarchy parameter space, reaching discovery sensitivity to half lives exceeding 10²⁸ years. To achieve sufficiently low background for this search, LEGEND combines the passive shielding of the underground laboratory of LNGS, a liquid argon scintillation detector, and powerful HPGe pulse shape discrimination (PSD) techniques. This talk will discuss preliminary results from the Collimated Alphas, Gammas, and Electrons (CAGE) Scanner, a test stand at UW that aims to better understand surface events in germanium detectors, which are a leading background risk, and the development of new pulse shape parameters designed to effectively mitigate this background source.