LATERAL DISTRIBUTION OF CHARGED-PARTICLES IN GIANT AIR SHOWERS ABOVE 1-EEV OBSERVED BY AGASA

We have studied the lateral distribution of charged particles associat ed with giant air showers and the attenuation of the local particle de nsity at 600 m from the core, S600, with atmospheric depth using data collected with the Akeno Giant Air Shower Array (AGASA). The lateral d istribution at distances of more than 1 km from the core has been obse rved to be much steeper than that suggested by some of the earlier mea surements. The shape of the lateral distribution function has been obs erved to depend on the zenith angle of showers but there is no signifi cant evidence for the dependence on the primary energy, within the res olution of the array. The systematic errors in energy estimation due t o the uncertainties in the lateral distribution and the attenuation le ngth of S600 are smaller than statistical errors. These errors have be en estimated to be approximately 5% and approximately 3% respectively for near vertical showers with sec theta = 1.1, and approximately 10% and approximately 12% respectively for showers with sec theta = 1.4.