Development of Germanium (Ge) Ring Contact Detectors for Ge-based Neutrinoless Double-Beta Decay Experiment

The next generation neutrinoless double beta (0νββ) decay experiments aim to achieve the decay half-life of ~10²⁸ years. Germanium (Ge)-based experiment has great chance to achieve the discovery potential for this rare decay process due to its excellent energy resolution to reject 2νββ decay events. LEGEND-1000 prefers large-size detectors (>3 kg per detector), which will further reduce backgrounds, complexity, and cost. This talk will explore large-size detectors through conducting research and development (R&D) of Ge ring-contact (GeRC) detectors using high-purity Ge crystals grown at USD. The detector is designed between ORNL, UNC, and USD. We fabricate GeRC detectors at TAMU and test them at UNC. The GeRC detector technology can potentially increase the mass per Ge detector for LEGEND-1000. Due to the physical properties of Ge crystal and the geometric structure of the detector, the fabrication process is complex. At TAMU, we have overcome many difficulties and gained a lot of experience in making GeRC detectors. This talk will report some initial results about the GeRC detector fabricated at TAMU using the USD-grown crystals.