Simulation Studies of the Directivity in Detection of Solar Neutrinos Using Deep Sea Water

摘要:
Cerenkov detector has its advantage to construct the reaction vertex and incident direction of the energetic particles, and thus to locate the emission source. We propose to measure the neutrino source by modular photomultiplier tube (PMT) array using  clean and transparent deep sea water as sensitive medium. The feasibility of the detection of solar neutrino is demonstrated by full simulation based on Geant4 packages. The production and transport of Cerenkov photons generated by the neutrino electron scattering are simulated. Houth transform method is applied to reconstruct the vertex and the direction of the high-speed electron,  as well as the incident direction of the neutrinos. The dominant background of gamma radiation from 40K in sea water can be suppressed by a factor of 10^7 if a threshold on the number of firing PMTs is introduced. The total reconstruction efficiency increases with the incident energy, reaching 25% for 6 MeV neutrino and 52% for 10 MeV neutrino, respectively. To locate an existing neutrino source, a certain number of neutrino events are required, depending on the background intensity above the threshold. The simulation results reveal how feasible to measure solar neutrino using deep sea water.