Cosmic ray muon flux at the Sanford Underground Laboratory at Homestake

Measuring the muon flux is important to the Sanford Underground Laboratory at Homestake, for which several low background experiments are being planned. The nearly vertical cosmic ray muon flux was measured in three locations at this laboratory: on the surface (1.149±0.017 x10-2 cm-2 s-1 sr-1), at the 800 ft (0.712 km w.e.) level (2.67±0.06 x10-6 cm-2 s-1 sr-1), and at the 2000 ft (1.78 km w.e.) level (2.56±0.25 x10-7 cm-2 s-1 sr-1). These fluxes agree well with model predictions.