Electron Density Distribution near Large Air Shower Axes at Sea Level

Abstract

A large, multiple-wire ionization chamber has been used to sample 20 separate areas of the plane of observation to obtain detailed "profiles" of the structure of large air showers within about 2 meters of their axes. Interpretation of the data is based on (1) quantitative calculations of the transition effect in 0.305 radiation lengths of dural, and (2) a semiquantitative discussion of the fluctuations in the lateral-distribution function. Lateral distribution functions for electrons and photons of various energies have been calculated for $r<\mathrm{}10\mathrm{}$ meters at the shower maximum and the function for electrons of all energies turns out to be essentially equal to the one given by Molière. No drastic revision of the calculated distribution function is indicated by the data, but a flatter distribution than that calculated is not ruled out. Evidence for a multiple-core structure in a small percentage of cases is presented.