Mean Free Path of High-Energy Nucleons in the Atmosphere

Abstract

An altitude-variation experiment to determine the absorption mean free path in the atmosphere of high-energy nucleons of the cosmic radiation has been performed using a large ionization chamber and associated counter trays. It is estimated that the nucleons studied in this experiment range in energy from 200 to 2000 Bev, which is a higher energy region than has been investigated previously in similar experiments. The absorption mean free path for protons is found to be 125±9 g/${\mathrm{cm}}^2$ and for neutrons 105±8 g/${\mathrm{cm}}^2$, and the charged-to-neutral ratio is 1.54±0.15. These values are in good agreement with previous altitude variation experiments. There seems to be no change in the mean free path with energy.