Lateral distribution of muon pairs in underground cosmic ray showers

The lateral distribution of cosmic-ray muon showers underground has been studied by measuring the separations between about 5000 pairs of muons. Results are presented in terms of a counting rate for an equivalent pair of one metre-square detectors beneath 2500 hg cm-2 rock and orientated at 45 degrees zenith. For separations from 0 to 50 m an approximately exponential dependence of the counting rate on detector separation is observed which decreases by a factor e in of the order of 10 m.