Muons in large extensive air showers

The responses of shielded scintillators and flash tubes to muons in EAS have been compared. At low densities (< 3 m-2) precise agreement is obtained but at higher densities the flash tubes tend to saturate. Experimental mean muon density lateral distributions as derived from different arrays show good agreement and indicate that such muon studies provide an accurate method of calibrating the EAS arrays relative to each other. An attempt to detect EAS fluctuations by sampling the muons with a 12 m2 detector shows the difficulty of this technique. However, by selecting the 10% of showers with densities 1.5 sigma above average density a significant anisotropy in celestial co-ordinates of the arrival direction of 'muon-rich' showers is observed. The implication of such an anisotropy (approximately 13 hr RA) is pointed out. (orig.)