UC Berkeley

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 a 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-2 s-1 sr-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 0.76±0.03 for liquid-scintillator targets.