Experiments on the Average Characteristics of Cascade Showers Produced in Lead by 500- and 1000-MeV Electrons

Abstract

The average number and the energy spectrum of shower electrons present under various thicknesses of lead were obtained with the aid of multiplate and magnetic cloud chambers. The relation between observed track length and incident electron energy was found to be incident energy (MeV) = (23.6±1.6)×track length (radiation lengths). The observed number of shower electrons with energy greater than 10 MeV is in good agreement with that predicted by recent Monte Carlo calculations; however, low-energy electrons (not included in the calculations) were found to be a large fraction of those present at large depths. Measured probabilities $p_n$ that exactly $n$ electrons emerge from the lower surface of a 0.75-radiation-length lead plate when one electron is incident from above are given as a function of incident electron energy.