Mean Free Path of the High EnergyNComponent of Cosmic Radiation

The mean free path of charged particles that produce penetrating showers has been measured in carbon, sulfur, and iron. Preliminary measurements with carbon were carried out at 130-m elevation and the mean free path obtained was 89±{}12 g/cm². Measurements at 2765-m elevation gave mean free paths in carbon, sulfur, and iron of 65±{}5, 76±{}7, and 115±{}12 g/cm², respectively. The carbon data were used to get an estimate of the mean free path in nuclear matter of high energy nucleons.