Simulating NuDot: A Neutrinoless Double-Beta Decay Detector with Direction Reconstruction in Liquid Scintillator*

The theorized process of neutrinoless double-beta decay (0𝜈𝛽𝛽), in which the two antineutrinos emitted during a double-beta minus (𝛽−) decay annihilate with each other, could provide a mechanism to explain the matter-antimatter imbalance in the universe. Liquid scintillator-based 0𝜈𝛽𝛽 searches use isotropic scintillation light to measure the energy of the outgoing 𝛽− particles, searching for a peak at the predicted energy of the 0𝜈𝛽𝛽 decay. NuDot, a 1/2-ton research and development effort for the next generation of these detectors that is undergoing commissioning at Bates Laboratory. It will additionally use directional Cherenkov light to identify otherwise irreducible background events.

Cherenkov and scintillation signals will be distinguished by precise timing. A simulation of NuDot's geometry was made using the RAT-PAC package, a liquid scintillator framework built on top of the Geant4 particle physics engine. This simulation was used to guide the development of a timing calibration plan for NuDot's 211 photomultiplier tubes. Results from simulations of collimated source runs and the final calibration plan will be presented.