Measurements of Muon and Muon-induced Fluxes Using Gadolinium-Doped Liquid Scintillator at the China Jinping Underground Laboratory

摘要: We present the results of an experiment conducted to measure cosmic-ray muons and muon-induced fluxes at the China Jinping Underground Laboratory. Utilizing a 28-liter 0.5% gadolinium-doped liquid scintillator detector, which operated stably for 412 days in a 1-meter-thick polyethylene shielding, we reconstructed saturated signal pulses and pulse shape discrimination to facilitate measurements across a range starting from 0.2 MeV. The event rates incorporating mountain geometry effects for cosmic rays and their induced particles are derived. The experimental results show that cosmic ray muon flux is (3.64 ± 0.69(stat.) ± 0.25(syst.)) × 10^{-10} cm^{-2} s^{-1}, muon-induced electron flux is (5.59 ± 1.06(stat.) ± 0.40(syst.)) × 10^{-10} cm^{-2} s^{-1}, and the upper limit of the muon-induced neutron flux is 3.52 × 10^{-9} cm^{-2} s^{-1}. They indicated that no significant excess is observed at a 90% confidence-level, particularly no muon-induced neutrons above 10 MeVee is detected.