Lateral distribution of charged particles in giant air showers above 1 EeV observed by AGASA

We have studied the lateral distribution of charged particles associated with giant air showers and the attenuation of the local particle density at 600 m from the core, S600, with atmospheric depth using data collected with the Akeno Giant Air Shower Array (AGASA). The lateral distribution at distances of more than 1 km from the core has been observed to be much steeper than that suggested by some of the earlier measurements. The shape of the lateral distribution function has been observed to depend on the zenith angle of showers but there is no significant evidence for the dependence on the primary energy, within the resolution of the array. The systematic errors in energy estimation due to the uncertainties in the lateral distribution and the attenuation length of S600 are smaller than statistical errors. These errors have been 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.