Multiple Secondary Effects of the Penetrating Cosmic Radiation at Sea Level

Abstract

The production of multiple secondary particles by cosmic rays under thick layers of lead has been studied with coincidence counters and with a cloud chamber. Part of the coincidences obtained under 15 cm of lead is attributed to groups of particles of atmospheric origin associated with extensive showers. The other part is due to a local effect produced in the lead by single penetrating particles. Among the particles emitted in these processes, some have the penetrating power of low energy mesons.