Andrey Elagin
(University of Chicago)

Directional Liquid Scintillator Detector for Neutrinoless Double-Beta Decay

Observation of neutrinoless double-beta decay (0νßß-decay) would establish that the neutrino is a Majorana particle. I will briefly review the history, experimental challenges, and current status of searches for this rare nuclear process. I will then discuss an idea of using fast photo-detectors in a large liquid scintillator detector to search for 0νββ-decay. Selection of early photons using fast photo-detectors separates prompt direc- tional Cherenkov light from delayed isotropic scintillation light. Electrons from 0νββ-decay are often exceed Cherenkov threshold in liquid scintillator. This leads to the possibility to reconstruct event topology of 0νßß-decay candidate events by analyzing spatial distribution of early photons. Using a simulation of 6.5 m radius liquid scintillator detector with 100 ps resolution photo-detectors, I will show that a spherical harmonics analysis of early photons provides a discriminating power between two track 0νßß-decay and single track 8B solar neutrino event topologies. Large-Area Picosecond Photo-Detector (LAPPD™) is an attractive option of photo-detector with sufficient time resolution. LAPPD™ is a 20×20 cm2 thin, planar, glass-body detector with two Micro-Channel Plates in a chevron geometry with 8º bias angle. With a complete detector system approximating the detector design, we have measured a gain of up to 2×107 of-flight resolution of ∼60 ps, differential time resolution of ∼5 ps, and spatial resolution of better than 1 mm in two dimensions. I will conclude by discussing the development of LAPPD™.