The arrival time distribution of muons in extensive air showers

The time spread of muons within EAS has been determined by measuring the time of arrival of individual muons with respect to the extreme shower front with an accuracy of +or-10 ns. The integral time distributions averaged over a group of showers are presented as a function of shower parameters. For near vertical showers it is found that the 10%-90% time spread of muons increases from about 100 ns at an EAS core distance of 150 m to about 160 ns at 450 m. These results are shown to be in reasonable agreement with predictions based on model calculations.