WIDG Seminar: Gulden (Joule) Othman, UNC, “CAGE Scanner: Investigating Surface Backgrounds in HPGe Detectors for Neutrinoless Double-Beta Decay Searches”

LEGEND is a next-generation search for neutrinoless double-beta decay in 76Ge. It will incorporate successful aspects of two 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 used in MAJORANA and GERDA. Passivated surfaces and thin dead layers on these detectors make them susceptible to surface backgrounds, such as from alphas and betas, 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. The CAGE (Collimated Alphas, Gammas, and Electrons) scanner is currently being constructed at the Center for Experimental Nuclear and Particle Astrophysics (CENPA) at the University of Washington. CAGE is an internal-source scanning cryostat designed to study the passivated surface of HPGe detectors using collimated alpha, beta, and gamma sources. This talk will focus on the design, simulations, and current construction status of the CAGE scanner for a first scan with a MAJORANA-style p-type point contact detector.