An Internal-Source Scanning Cryostat for HPGe Detectors

LEGEND is a next-generation search for neutrinoless double-beta decay in ⁷⁶Ge which will incorporate successful aspects of the current-generation experiments, the MAJORANA DEMONSTRATOR and GERDA. In addition to new detector designs, LEGEND will utilize the ⁷⁶Ge-enriched high-purity germanium (HPGe) detectors currently in use in MAJORANA and GERDA. The MAJORANA DEMONSTRATOR employs HPGe detectors of a P-type Point Contact (PPC) geometry. Passivated surfaces on the MAJORANA PPCs makes them susceptible to surface backgrounds, such as alphas, which can potentially contaminate the region of interest for neutrinoless double-beta decay. Understanding the detector response to these surface backgrounds is crucial in both current and next-generation ⁷⁶Ge neutrinoless double-beta decay searches. This talk will focus on R&D efforts underway to examine the response of the passivated surface of MAJORANA-style PPCs to surface backgrounds in dedicated test stands using collimated alpha, beta, and gamma sources.