Study of a mini-array for the Linsley effect in cosmic-ray air showers

The arrival-time distribution of shower particles far from the core has been measured as a function of shower axis distance at the Akeno Observatory by a cluster of 64 scintillators (total area 16 m2) located near the centre of the 1 km2 array. More than 3500 1 km2 array events and about 300 20 km2 array events have been analysed. From a measurement of time spread, the shower axis distance can be determined with an uncertainty of 25 to 30% with this detector system. The resulting uncertainty in shower size, including a 60% uncertainty in particle density measurement, is 120 to 140%. The resultant smearing of changes in slope of the frequency spectrum of incident showers is calculated. (author)