We have measured the muon flux and production rate of muon-induced neutrons
at a depth of 611 m water equivalent. Our apparatus comprises three layers of
crossed plastic scintillator hodoscopes for tracking the incident cosmic-ray
muons and 760 L of gadolinium-doped liquid scintillator for producing and
detecting neutrons. The vertical muon intensity was measured to be Iμ=(5.7±0.6)×10−6 cm−2s−1sr−1. The yield of
muon-induced neutrons in the liquid scintillator was determined to be Yn=(1.19±0.08(stat)±0.21(syst))×10−4
neutrons/(μ⋅g⋅cm−2). A fit to the recently measured neutron
yields at different depths gave a mean muon energy dependence of ⟨Eμ⟩0.76±0.03 for liquid-scintillator targets.Comment: 14 pages, 17 figures, 3 table