Daya Bay II and Future Reactor Experiments

Abstract

The observation of the large neutrino mixing angle sin22θ13 accelerates the experiments to measure the neutrino mass hierarchy and the CP phase. Daya Bay II, as a medium baseline reactor experiment, can measure the neutrino mass hierarchy independent of the CP phase. We study the sensitivity on the mass hierarchy and find the 3σ determination is possible after 6 years of running using a 20 kton detector with an energy resolution of 3%/ Evis at a 45-60 km baseline. In addition, Daya Bay II can measure the neutrino mixing parameters (Δm212,Δm312, and sin2θ12) with precision better than 1%. The possible site of Daya Bay II experiment is studied based on the locations of the reactor power plants. As a preliminary design, the detector contains liquid scintillator as target and uses photomultiplier tubes (PMTs) to collect the scintillation light. The technical challenges on the scintillator and PMTs are discussed.